diff --git a/src/vnet.am b/src/vnet.am
index d6a5d52..040a4cd 100644
--- a/src/vnet.am
+++ b/src/vnet.am
@@ -917,16 +917,22 @@
 libvnet_la_SOURCES +=				\
   vnet/devices/virtio/device.c			\
   vnet/devices/virtio/node.c			\
-  vnet/devices/virtio/vhost-user.c		\
+  vnet/devices/virtio/vhost_user.c		\
+  vnet/devices/virtio/vhost_user_input.c	\
+  vnet/devices/virtio/vhost_user_output.c	\
   vnet/devices/virtio/vhost_user_api.c		\
   vnet/devices/virtio/virtio.c
 
 
 nobase_include_HEADERS +=			\
   vnet/devices/virtio/virtio.h			\
-  vnet/devices/virtio/vhost-user.h		\
+  vnet/devices/virtio/vhost_user.h		\
   vnet/devices/virtio/vhost_user.api.h
 
+libvnet_multiversioning_sources +=		\
+  vnet/devices/virtio/vhost_user_input.c	\
+  vnet/devices/virtio/vhost_user_output.c
+
 API_FILES += vnet/devices/virtio/vhost_user.api
 
 ########################################
diff --git a/src/vnet/devices/virtio/vhost-user.c b/src/vnet/devices/virtio/vhost-user.c
deleted file mode 100644
index f6406d4..0000000
--- a/src/vnet/devices/virtio/vhost-user.c
+++ /dev/null
@@ -1,3758 +0,0 @@
-/*
- *------------------------------------------------------------------
- * vhost.c - vhost-user
- *
- * Copyright (c) 2014 Cisco and/or its affiliates.
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at:
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *------------------------------------------------------------------
- */
-
-#include <fcntl.h>		/* for open */
-#include <sys/ioctl.h>
-#include <sys/socket.h>
-#include <sys/un.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <sys/uio.h>		/* for iovec */
-#include <netinet/in.h>
-#include <sys/vfs.h>
-
-#include <linux/if_arp.h>
-#include <linux/if_tun.h>
-
-#include <vlib/vlib.h>
-#include <vlib/unix/unix.h>
-
-#include <vnet/ip/ip.h>
-
-#include <vnet/ethernet/ethernet.h>
-#include <vnet/devices/devices.h>
-#include <vnet/feature/feature.h>
-
-#include <vnet/devices/virtio/vhost-user.h>
-
-/**
- * @file
- * @brief vHost User Device Driver.
- *
- * This file contains the source code for vHost User interface.
- */
-
-
-#define VHOST_DEBUG_VQ 0
-
-#define DBG_SOCK(args...)			\
-  {						\
-    vhost_user_main_t *_vum = &vhost_user_main; \
-    if (_vum->debug)				\
-      clib_warning(args);			\
-  };
-
-#if VHOST_DEBUG_VQ == 1
-#define DBG_VQ(args...) clib_warning(args);
-#else
-#define DBG_VQ(args...)
-#endif
-
-/*
- * When an RX queue is down but active, received packets
- * must be discarded. This value controls up to how many
- * packets will be discarded during each round.
- */
-#define VHOST_USER_DOWN_DISCARD_COUNT 256
-
-/*
- * When the number of available buffers gets under this threshold,
- * RX node will start discarding packets.
- */
-#define VHOST_USER_RX_BUFFER_STARVATION 32
-
-/*
- * On the receive side, the host should free descriptors as soon
- * as possible in order to avoid TX drop in the VM.
- * This value controls the number of copy operations that are stacked
- * before copy is done for all and descriptors are given back to
- * the guest.
- * The value 64 was obtained by testing (48 and 128 were not as good).
- */
-#define VHOST_USER_RX_COPY_THRESHOLD 64
-/*
- * On the transmit side, we keep processing the buffers from vlib in the while
- * loop and prepare the copy order to be executed later. However, the static
- * array which we keep the copy order is limited to VHOST_USER_COPY_ARRAY_N
- * entries. In order to not corrupt memory, we have to do the copy when the
- * static array reaches the copy threshold. We subtract 40 in case the code
- * goes into the inner loop for a maximum of 64k frames which may require
- * more array entries.
- */
-#define VHOST_USER_TX_COPY_THRESHOLD (VHOST_USER_COPY_ARRAY_N - 40)
-
-#define UNIX_GET_FD(unixfd_idx) ({ \
-    typeof(unixfd_idx) __unixfd_idx = (unixfd_idx); \
-    (__unixfd_idx != ~0) ? \
-	pool_elt_at_index (file_main.file_pool, \
-			   __unixfd_idx)->file_descriptor : -1; })
-
-#define foreach_virtio_trace_flags \
-  _ (SIMPLE_CHAINED, 0, "Simple descriptor chaining") \
-  _ (SINGLE_DESC,  1, "Single descriptor packet") \
-  _ (INDIRECT, 2, "Indirect descriptor") \
-  _ (MAP_ERROR, 4, "Memory mapping error")
-
-typedef enum
-{
-#define _(n,i,s) VIRTIO_TRACE_F_##n,
-  foreach_virtio_trace_flags
-#undef _
-} virtio_trace_flag_t;
-
-vlib_node_registration_t vhost_user_input_node;
-
-#define foreach_vhost_user_tx_func_error      \
-  _(NONE, "no error")  \
-  _(NOT_READY, "vhost vring not ready")  \
-  _(DOWN, "vhost interface is down")  \
-  _(PKT_DROP_NOBUF, "tx packet drops (no available descriptors)")  \
-  _(PKT_DROP_NOMRG, "tx packet drops (cannot merge descriptors)")  \
-  _(MMAP_FAIL, "mmap failure") \
-  _(INDIRECT_OVERFLOW, "indirect descriptor table overflow")
-
-typedef enum
-{
-#define _(f,s) VHOST_USER_TX_FUNC_ERROR_##f,
-  foreach_vhost_user_tx_func_error
-#undef _
-    VHOST_USER_TX_FUNC_N_ERROR,
-} vhost_user_tx_func_error_t;
-
-static char *vhost_user_tx_func_error_strings[] = {
-#define _(n,s) s,
-  foreach_vhost_user_tx_func_error
-#undef _
-};
-
-#define foreach_vhost_user_input_func_error      \
-  _(NO_ERROR, "no error")  \
-  _(NO_BUFFER, "no available buffer")  \
-  _(MMAP_FAIL, "mmap failure")  \
-  _(INDIRECT_OVERFLOW, "indirect descriptor overflows table")  \
-  _(UNDERSIZED_FRAME, "undersized ethernet frame received (< 14 bytes)") \
-  _(FULL_RX_QUEUE, "full rx queue (possible driver tx drop)")
-
-typedef enum
-{
-#define _(f,s) VHOST_USER_INPUT_FUNC_ERROR_##f,
-  foreach_vhost_user_input_func_error
-#undef _
-    VHOST_USER_INPUT_FUNC_N_ERROR,
-} vhost_user_input_func_error_t;
-
-static char *vhost_user_input_func_error_strings[] = {
-#define _(n,s) s,
-  foreach_vhost_user_input_func_error
-#undef _
-};
-
-/* *INDENT-OFF* */
-static vhost_user_main_t vhost_user_main = {
-  .mtu_bytes = 1518,
-};
-
-VNET_HW_INTERFACE_CLASS (vhost_interface_class, static) = {
-  .name = "vhost-user",
-};
-/* *INDENT-ON* */
-
-static u8 *
-format_vhost_user_interface_name (u8 * s, va_list * args)
-{
-  u32 i = va_arg (*args, u32);
-  u32 show_dev_instance = ~0;
-  vhost_user_main_t *vum = &vhost_user_main;
-
-  if (i < vec_len (vum->show_dev_instance_by_real_dev_instance))
-    show_dev_instance = vum->show_dev_instance_by_real_dev_instance[i];
-
-  if (show_dev_instance != ~0)
-    i = show_dev_instance;
-
-  s = format (s, "VirtualEthernet0/0/%d", i);
-  return s;
-}
-
-static int
-vhost_user_name_renumber (vnet_hw_interface_t * hi, u32 new_dev_instance)
-{
-  // FIXME: check if the new dev instance is already used
-  vhost_user_main_t *vum = &vhost_user_main;
-  vec_validate_init_empty (vum->show_dev_instance_by_real_dev_instance,
-			   hi->dev_instance, ~0);
-
-  vum->show_dev_instance_by_real_dev_instance[hi->dev_instance] =
-    new_dev_instance;
-
-  DBG_SOCK ("renumbered vhost-user interface dev_instance %d to %d",
-	    hi->dev_instance, new_dev_instance);
-
-  return 0;
-}
-
-static_always_inline void *
-map_guest_mem (vhost_user_intf_t * vui, uword addr, u32 * hint)
-{
-  int i = *hint;
-  if (PREDICT_TRUE ((vui->regions[i].guest_phys_addr <= addr) &&
-		    ((vui->regions[i].guest_phys_addr +
-		      vui->regions[i].memory_size) > addr)))
-    {
-      return (void *) (vui->region_mmap_addr[i] + addr -
-		       vui->regions[i].guest_phys_addr);
-    }
-#if __SSE4_2__
-  __m128i rl, rh, al, ah, r;
-  al = _mm_set1_epi64x (addr + 1);
-  ah = _mm_set1_epi64x (addr);
-
-  rl = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_lo[0]);
-  rl = _mm_cmpgt_epi64 (al, rl);
-  rh = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_hi[0]);
-  rh = _mm_cmpgt_epi64 (rh, ah);
-  r = _mm_and_si128 (rl, rh);
-
-  rl = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_lo[2]);
-  rl = _mm_cmpgt_epi64 (al, rl);
-  rh = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_hi[2]);
-  rh = _mm_cmpgt_epi64 (rh, ah);
-  r = _mm_blend_epi16 (r, _mm_and_si128 (rl, rh), 0x22);
-
-  rl = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_lo[4]);
-  rl = _mm_cmpgt_epi64 (al, rl);
-  rh = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_hi[4]);
-  rh = _mm_cmpgt_epi64 (rh, ah);
-  r = _mm_blend_epi16 (r, _mm_and_si128 (rl, rh), 0x44);
-
-  rl = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_lo[6]);
-  rl = _mm_cmpgt_epi64 (al, rl);
-  rh = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_hi[6]);
-  rh = _mm_cmpgt_epi64 (rh, ah);
-  r = _mm_blend_epi16 (r, _mm_and_si128 (rl, rh), 0x88);
-
-  r = _mm_shuffle_epi8 (r, _mm_set_epi64x (0, 0x0e060c040a020800));
-  i = count_trailing_zeros (_mm_movemask_epi8 (r) |
-			    (1 << VHOST_MEMORY_MAX_NREGIONS));
-
-  if (i < vui->nregions)
-    {
-      *hint = i;
-      return (void *) (vui->region_mmap_addr[i] + addr -
-		       vui->regions[i].guest_phys_addr);
-    }
-#elif __aarch64__ && __ARM_NEON
-  uint64x2_t al, ah, rl, rh, r;
-  uint32_t u32 = 0;
-
-  al = vdupq_n_u64 (addr + 1);
-  ah = vdupq_n_u64 (addr);
-
-  /*First Iteration */
-  rl = vld1q_u64 (&vui->region_guest_addr_lo[0]);
-  rl = vcgtq_u64 (al, rl);
-  rh = vld1q_u64 (&vui->region_guest_addr_hi[0]);
-  rh = vcgtq_u64 (rh, ah);
-  r = vandq_u64 (rl, rh);
-  u32 |= (vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 0) & 0x1);
-  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 8) & 0x1) << 1);
-
-  if (u32)
-    {
-      i = count_trailing_zeros (u32);
-      goto vhost_map_guest_mem_done;
-    }
-
-  /*Second Iteration */
-  rl = vld1q_u64 (&vui->region_guest_addr_lo[2]);
-  rl = vcgtq_u64 (al, rl);
-  rh = vld1q_u64 (&vui->region_guest_addr_hi[2]);
-  rh = vcgtq_u64 (rh, ah);
-  r = vandq_u64 (rl, rh);
-  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 0) & 0x1) << 2);
-  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 8) & 0x1) << 3);
-
-  if (u32)
-    {
-      i = count_trailing_zeros (u32);
-      goto vhost_map_guest_mem_done;
-    }
-
-  /*Third Iteration */
-  rl = vld1q_u64 (&vui->region_guest_addr_lo[4]);
-  rl = vcgtq_u64 (al, rl);
-  rh = vld1q_u64 (&vui->region_guest_addr_hi[4]);
-  rh = vcgtq_u64 (rh, ah);
-  r = vandq_u64 (rl, rh);
-  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 0) & 0x1) << 4);
-  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 8) & 0x1) << 5);
-
-  if (u32)
-    {
-      i = count_trailing_zeros (u32);
-      goto vhost_map_guest_mem_done;
-    }
-
-  /*Fourth Iteration */
-  rl = vld1q_u64 (&vui->region_guest_addr_lo[6]);
-  rl = vcgtq_u64 (al, rl);
-  rh = vld1q_u64 (&vui->region_guest_addr_hi[6]);
-  rh = vcgtq_u64 (rh, ah);
-  r = vandq_u64 (rl, rh);
-  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 0) & 0x1) << 6);
-  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 8) & 0x1) << 7);
-
-  i = count_trailing_zeros (u32 | (1 << VHOST_MEMORY_MAX_NREGIONS));
-
-vhost_map_guest_mem_done:
-  if (i < vui->nregions)
-    {
-      *hint = i;
-      return (void *) (vui->region_mmap_addr[i] + addr -
-		       vui->regions[i].guest_phys_addr);
-    }
-#else
-  for (i = 0; i < vui->nregions; i++)
-    {
-      if ((vui->regions[i].guest_phys_addr <= addr) &&
-	  ((vui->regions[i].guest_phys_addr + vui->regions[i].memory_size) >
-	   addr))
-	{
-	  *hint = i;
-	  return (void *) (vui->region_mmap_addr[i] + addr -
-			   vui->regions[i].guest_phys_addr);
-	}
-    }
-#endif
-  DBG_VQ ("failed to map guest mem addr %llx", addr);
-  *hint = 0;
-  return 0;
-}
-
-static inline void *
-map_user_mem (vhost_user_intf_t * vui, uword addr)
-{
-  int i;
-  for (i = 0; i < vui->nregions; i++)
-    {
-      if ((vui->regions[i].userspace_addr <= addr) &&
-	  ((vui->regions[i].userspace_addr + vui->regions[i].memory_size) >
-	   addr))
-	{
-	  return (void *) (vui->region_mmap_addr[i] + addr -
-			   vui->regions[i].userspace_addr);
-	}
-    }
-  return 0;
-}
-
-static long
-get_huge_page_size (int fd)
-{
-  struct statfs s;
-  fstatfs (fd, &s);
-  return s.f_bsize;
-}
-
-static void
-unmap_all_mem_regions (vhost_user_intf_t * vui)
-{
-  int i, r;
-  for (i = 0; i < vui->nregions; i++)
-    {
-      if (vui->region_mmap_addr[i] != MAP_FAILED)
-	{
-
-	  long page_sz = get_huge_page_size (vui->region_mmap_fd[i]);
-
-	  ssize_t map_sz = (vui->regions[i].memory_size +
-			    vui->regions[i].mmap_offset +
-			    page_sz - 1) & ~(page_sz - 1);
-
-	  r =
-	    munmap (vui->region_mmap_addr[i] - vui->regions[i].mmap_offset,
-		    map_sz);
-
-	  DBG_SOCK
-	    ("unmap memory region %d addr 0x%lx len 0x%lx page_sz 0x%x", i,
-	     vui->region_mmap_addr[i], map_sz, page_sz);
-
-	  vui->region_mmap_addr[i] = MAP_FAILED;
-
-	  if (r == -1)
-	    {
-	      clib_warning ("failed to unmap memory region (errno %d)",
-			    errno);
-	    }
-	  close (vui->region_mmap_fd[i]);
-	}
-    }
-  vui->nregions = 0;
-}
-
-static void
-vhost_user_tx_thread_placement (vhost_user_intf_t * vui)
-{
-  //Let's try to assign one queue to each thread
-  u32 qid = 0;
-  u32 thread_index = 0;
-  vui->use_tx_spinlock = 0;
-  while (1)
-    {
-      for (qid = 0; qid < VHOST_VRING_MAX_N / 2; qid++)
-	{
-	  vhost_user_vring_t *rxvq = &vui->vrings[VHOST_VRING_IDX_RX (qid)];
-	  if (!rxvq->started || !rxvq->enabled)
-	    continue;
-
-	  vui->per_cpu_tx_qid[thread_index] = qid;
-	  thread_index++;
-	  if (thread_index == vlib_get_thread_main ()->n_vlib_mains)
-	    return;
-	}
-      //We need to loop, meaning the spinlock has to be used
-      vui->use_tx_spinlock = 1;
-      if (thread_index == 0)
-	{
-	  //Could not find a single valid one
-	  for (thread_index = 0;
-	       thread_index < vlib_get_thread_main ()->n_vlib_mains;
-	       thread_index++)
-	    {
-	      vui->per_cpu_tx_qid[thread_index] = 0;
-	    }
-	  return;
-	}
-    }
-}
-
-/**
- * @brief Unassign existing interface/queue to thread mappings and re-assign
- * new interface/queue to thread mappings
- */
-static void
-vhost_user_rx_thread_placement ()
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui;
-  vhost_user_vring_t *txvq;
-  vnet_main_t *vnm = vnet_get_main ();
-  u32 qid;
-  int rv;
-  u16 *queue;
-
-  // Scrap all existing mappings for all interfaces/queues
-  /* *INDENT-OFF* */
-  pool_foreach (vui, vum->vhost_user_interfaces, {
-      vec_foreach (queue, vui->rx_queues)
-	{
-	  rv = vnet_hw_interface_unassign_rx_thread (vnm, vui->hw_if_index,
-						     *queue);
-	  if (rv)
-	    clib_warning ("Warning: unable to unassign interface %d, "
-			  "queue %d: rc=%d", vui->hw_if_index, *queue, rv);
-	}
-      vec_reset_length (vui->rx_queues);
-  });
-  /* *INDENT-ON* */
-
-  // Create the rx_queues for all interfaces
-  /* *INDENT-OFF* */
-  pool_foreach (vui, vum->vhost_user_interfaces, {
-      for (qid = 0; qid < VHOST_VRING_MAX_N / 2; qid++)
-	{
-	  txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)];
-	  if (txvq->started)
-	    {
-	      if (txvq->mode == VNET_HW_INTERFACE_RX_MODE_UNKNOWN)
-		/* Set polling as the default */
-		txvq->mode = VNET_HW_INTERFACE_RX_MODE_POLLING;
-	      vec_add1 (vui->rx_queues, qid);
-	    }
-	}
-  });
-  /* *INDENT-ON* */
-
-  // Assign new mappings for all interfaces/queues
-  /* *INDENT-OFF* */
-  pool_foreach (vui, vum->vhost_user_interfaces, {
-      vnet_hw_interface_set_input_node (vnm, vui->hw_if_index,
-					vhost_user_input_node.index);
-      vec_foreach (queue, vui->rx_queues)
-	{
-	  vnet_hw_interface_assign_rx_thread (vnm, vui->hw_if_index, *queue,
-					      ~0);
-	  txvq = &vui->vrings[VHOST_VRING_IDX_TX (*queue)];
-	  rv = vnet_hw_interface_set_rx_mode (vnm, vui->hw_if_index, *queue,
-					      txvq->mode);
-	  if (rv)
-	    clib_warning ("Warning: unable to set rx mode for interface %d, "
-			  "queue %d: rc=%d", vui->hw_if_index, *queue, rv);
-	}
-  });
-  /* *INDENT-ON* */
-}
-
-/** @brief Returns whether at least one TX and one RX vring are enabled */
-int
-vhost_user_intf_ready (vhost_user_intf_t * vui)
-{
-  int i, found[2] = { };	//RX + TX
-
-  for (i = 0; i < VHOST_VRING_MAX_N; i++)
-    if (vui->vrings[i].started && vui->vrings[i].enabled)
-      found[i & 1] = 1;
-
-  return found[0] && found[1];
-}
-
-static void
-vhost_user_update_iface_state (vhost_user_intf_t * vui)
-{
-  /* if we have pointers to descriptor table, go up */
-  int is_up = vhost_user_intf_ready (vui);
-  if (is_up != vui->is_up)
-    {
-      DBG_SOCK ("interface %d %s", vui->sw_if_index,
-		is_up ? "ready" : "down");
-      vnet_hw_interface_set_flags (vnet_get_main (), vui->hw_if_index,
-				   is_up ? VNET_HW_INTERFACE_FLAG_LINK_UP :
-				   0);
-      vui->is_up = is_up;
-    }
-  vhost_user_rx_thread_placement ();
-  vhost_user_tx_thread_placement (vui);
-}
-
-static void
-vhost_user_set_interrupt_pending (vhost_user_intf_t * vui, u32 ifq)
-{
-  u32 qid;
-  vnet_main_t *vnm = vnet_get_main ();
-
-  qid = ifq & 0xff;
-  if ((qid & 1) == 0)
-    /* Only care about the odd number, or TX, virtqueue */
-    return;
-
-  if (vhost_user_intf_ready (vui))
-    // qid >> 1 is to convert virtqueue number to vring queue index
-    vnet_device_input_set_interrupt_pending (vnm, vui->hw_if_index, qid >> 1);
-}
-
-static clib_error_t *
-vhost_user_callfd_read_ready (clib_file_t * uf)
-{
-  __attribute__ ((unused)) int n;
-  u8 buff[8];
-
-  n = read (uf->file_descriptor, ((char *) &buff), 8);
-
-  return 0;
-}
-
-static clib_error_t *
-vhost_user_kickfd_read_ready (clib_file_t * uf)
-{
-  __attribute__ ((unused)) int n;
-  u8 buff[8];
-  vhost_user_intf_t *vui =
-    pool_elt_at_index (vhost_user_main.vhost_user_interfaces,
-		       uf->private_data >> 8);
-  u32 qid = uf->private_data & 0xff;
-
-  n = read (uf->file_descriptor, ((char *) &buff), 8);
-  DBG_SOCK ("if %d KICK queue %d", uf->private_data >> 8, qid);
-  if (!vui->vrings[qid].started ||
-      (vhost_user_intf_ready (vui) != vui->is_up))
-    {
-      vlib_worker_thread_barrier_sync (vlib_get_main ());
-      vui->vrings[qid].started = 1;
-      vhost_user_update_iface_state (vui);
-      vlib_worker_thread_barrier_release (vlib_get_main ());
-    }
-
-  vhost_user_set_interrupt_pending (vui, uf->private_data);
-  return 0;
-}
-
-/**
- * @brief Try once to lock the vring
- * @return 0 on success, non-zero on failure.
- */
-static inline int
-vhost_user_vring_try_lock (vhost_user_intf_t * vui, u32 qid)
-{
-  return __sync_lock_test_and_set (vui->vring_locks[qid], 1);
-}
-
-/**
- * @brief Spin until the vring is successfully locked
- */
-static inline void
-vhost_user_vring_lock (vhost_user_intf_t * vui, u32 qid)
-{
-  while (vhost_user_vring_try_lock (vui, qid))
-    ;
-}
-
-/**
- * @brief Unlock the vring lock
- */
-static inline void
-vhost_user_vring_unlock (vhost_user_intf_t * vui, u32 qid)
-{
-  *vui->vring_locks[qid] = 0;
-}
-
-static inline void
-vhost_user_vring_init (vhost_user_intf_t * vui, u32 qid)
-{
-  vhost_user_vring_t *vring = &vui->vrings[qid];
-  memset (vring, 0, sizeof (*vring));
-  vring->kickfd_idx = ~0;
-  vring->callfd_idx = ~0;
-  vring->errfd = -1;
-
-  /*
-   * We have a bug with some qemu 2.5, and this may be a fix.
-   * Feel like interpretation holy text, but this is from vhost-user.txt.
-   * "
-   * One queue pair is enabled initially. More queues are enabled
-   * dynamically, by sending message VHOST_USER_SET_VRING_ENABLE.
-   * "
-   * Don't know who's right, but this is what DPDK does.
-   */
-  if (qid == 0 || qid == 1)
-    vring->enabled = 1;
-}
-
-static inline void
-vhost_user_vring_close (vhost_user_intf_t * vui, u32 qid)
-{
-  vhost_user_vring_t *vring = &vui->vrings[qid];
-  if (vring->kickfd_idx != ~0)
-    {
-      clib_file_t *uf = pool_elt_at_index (file_main.file_pool,
-					   vring->kickfd_idx);
-      clib_file_del (&file_main, uf);
-      vring->kickfd_idx = ~0;
-    }
-  if (vring->callfd_idx != ~0)
-    {
-      clib_file_t *uf = pool_elt_at_index (file_main.file_pool,
-					   vring->callfd_idx);
-      clib_file_del (&file_main, uf);
-      vring->callfd_idx = ~0;
-    }
-  if (vring->errfd != -1)
-    {
-      close (vring->errfd);
-      vring->errfd = -1;
-    }
-  vhost_user_vring_init (vui, qid);
-}
-
-static inline void
-vhost_user_if_disconnect (vhost_user_intf_t * vui)
-{
-  vnet_main_t *vnm = vnet_get_main ();
-  int q;
-
-  vnet_hw_interface_set_flags (vnm, vui->hw_if_index, 0);
-
-  if (vui->clib_file_index != ~0)
-    {
-      clib_file_del (&file_main, file_main.file_pool + vui->clib_file_index);
-      vui->clib_file_index = ~0;
-    }
-
-  vui->is_up = 0;
-
-  for (q = 0; q < VHOST_VRING_MAX_N; q++)
-    vhost_user_vring_close (vui, q);
-
-  unmap_all_mem_regions (vui);
-  DBG_SOCK ("interface ifindex %d disconnected", vui->sw_if_index);
-}
-
-#define VHOST_LOG_PAGE 0x1000
-static_always_inline void
-vhost_user_log_dirty_pages_2 (vhost_user_intf_t * vui,
-			      u64 addr, u64 len, u8 is_host_address)
-{
-  if (PREDICT_TRUE (vui->log_base_addr == 0
-		    || !(vui->features & (1 << FEAT_VHOST_F_LOG_ALL))))
-    {
-      return;
-    }
-  if (is_host_address)
-    {
-      addr = pointer_to_uword (map_user_mem (vui, (uword) addr));
-    }
-  if (PREDICT_FALSE ((addr + len - 1) / VHOST_LOG_PAGE / 8 >= vui->log_size))
-    {
-      DBG_SOCK ("vhost_user_log_dirty_pages(): out of range\n");
-      return;
-    }
-
-  CLIB_MEMORY_BARRIER ();
-  u64 page = addr / VHOST_LOG_PAGE;
-  while (page * VHOST_LOG_PAGE < addr + len)
-    {
-      ((u8 *) vui->log_base_addr)[page / 8] |= 1 << page % 8;
-      page++;
-    }
-}
-
-static_always_inline void
-vhost_user_log_dirty_pages (vhost_user_intf_t * vui, u64 addr, u64 len)
-{
-  vhost_user_log_dirty_pages_2 (vui, addr, len, 0);
-}
-
-#define vhost_user_log_dirty_ring(vui, vq, member) \
-  if (PREDICT_FALSE(vq->log_used)) { \
-    vhost_user_log_dirty_pages(vui, vq->log_guest_addr + STRUCT_OFFSET_OF(vring_used_t, member), \
-                             sizeof(vq->used->member)); \
-  }
-
-static clib_error_t *
-vhost_user_socket_read (clib_file_t * uf)
-{
-  int n, i;
-  int fd, number_of_fds = 0;
-  int fds[VHOST_MEMORY_MAX_NREGIONS];
-  vhost_user_msg_t msg;
-  struct msghdr mh;
-  struct iovec iov[1];
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui;
-  struct cmsghdr *cmsg;
-  u8 q;
-  clib_file_t template = { 0 };
-  vnet_main_t *vnm = vnet_get_main ();
-
-  vui = pool_elt_at_index (vum->vhost_user_interfaces, uf->private_data);
-
-  char control[CMSG_SPACE (VHOST_MEMORY_MAX_NREGIONS * sizeof (int))];
-
-  memset (&mh, 0, sizeof (mh));
-  memset (control, 0, sizeof (control));
-
-  for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++)
-    fds[i] = -1;
-
-  /* set the payload */
-  iov[0].iov_base = (void *) &msg;
-  iov[0].iov_len = VHOST_USER_MSG_HDR_SZ;
-
-  mh.msg_iov = iov;
-  mh.msg_iovlen = 1;
-  mh.msg_control = control;
-  mh.msg_controllen = sizeof (control);
-
-  n = recvmsg (uf->file_descriptor, &mh, 0);
-
-  /* Stop workers to avoid end of the world */
-  vlib_worker_thread_barrier_sync (vlib_get_main ());
-
-  if (n != VHOST_USER_MSG_HDR_SZ)
-    {
-      if (n == -1)
-	{
-	  DBG_SOCK ("recvmsg returned error %d %s", errno, strerror (errno));
-	}
-      else
-	{
-	  DBG_SOCK ("n (%d) != VHOST_USER_MSG_HDR_SZ (%d)",
-		    n, VHOST_USER_MSG_HDR_SZ);
-	}
-      goto close_socket;
-    }
-
-  if (mh.msg_flags & MSG_CTRUNC)
-    {
-      DBG_SOCK ("MSG_CTRUNC is set");
-      goto close_socket;
-    }
-
-  cmsg = CMSG_FIRSTHDR (&mh);
-
-  if (cmsg && (cmsg->cmsg_len > 0) && (cmsg->cmsg_level == SOL_SOCKET) &&
-      (cmsg->cmsg_type == SCM_RIGHTS) &&
-      (cmsg->cmsg_len - CMSG_LEN (0) <=
-       VHOST_MEMORY_MAX_NREGIONS * sizeof (int)))
-    {
-      number_of_fds = (cmsg->cmsg_len - CMSG_LEN (0)) / sizeof (int);
-      clib_memcpy (fds, CMSG_DATA (cmsg), number_of_fds * sizeof (int));
-    }
-
-  /* version 1, no reply bit set */
-  if ((msg.flags & 7) != 1)
-    {
-      DBG_SOCK ("malformed message received. closing socket");
-      goto close_socket;
-    }
-
-  {
-    int rv;
-    rv =
-      read (uf->file_descriptor, ((char *) &msg) + VHOST_USER_MSG_HDR_SZ,
-	    msg.size);
-    if (rv < 0)
-      {
-	DBG_SOCK ("read failed %s", strerror (errno));
-	goto close_socket;
-      }
-    else if (rv != msg.size)
-      {
-	DBG_SOCK ("message too short (read %dB should be %dB)", rv, msg.size);
-	goto close_socket;
-      }
-  }
-
-  switch (msg.request)
-    {
-    case VHOST_USER_GET_FEATURES:
-      msg.flags |= 4;
-      msg.u64 = (1ULL << FEAT_VIRTIO_NET_F_MRG_RXBUF) |
-	(1ULL << FEAT_VIRTIO_NET_F_CTRL_VQ) |
-	(1ULL << FEAT_VIRTIO_F_ANY_LAYOUT) |
-	(1ULL << FEAT_VIRTIO_F_INDIRECT_DESC) |
-	(1ULL << FEAT_VHOST_F_LOG_ALL) |
-	(1ULL << FEAT_VIRTIO_NET_F_GUEST_ANNOUNCE) |
-	(1ULL << FEAT_VIRTIO_NET_F_MQ) |
-	(1ULL << FEAT_VHOST_USER_F_PROTOCOL_FEATURES) |
-	(1ULL << FEAT_VIRTIO_F_VERSION_1);
-      msg.u64 &= vui->feature_mask;
-      msg.size = sizeof (msg.u64);
-      DBG_SOCK ("if %d msg VHOST_USER_GET_FEATURES - reply 0x%016llx",
-		vui->hw_if_index, msg.u64);
-      break;
-
-    case VHOST_USER_SET_FEATURES:
-      DBG_SOCK ("if %d msg VHOST_USER_SET_FEATURES features 0x%016llx",
-		vui->hw_if_index, msg.u64);
-
-      vui->features = msg.u64;
-
-      if (vui->features &
-	  ((1 << FEAT_VIRTIO_NET_F_MRG_RXBUF) |
-	   (1ULL << FEAT_VIRTIO_F_VERSION_1)))
-	vui->virtio_net_hdr_sz = 12;
-      else
-	vui->virtio_net_hdr_sz = 10;
-
-      vui->is_any_layout =
-	(vui->features & (1 << FEAT_VIRTIO_F_ANY_LAYOUT)) ? 1 : 0;
-
-      ASSERT (vui->virtio_net_hdr_sz < VLIB_BUFFER_PRE_DATA_SIZE);
-      vnet_hw_interface_set_flags (vnm, vui->hw_if_index, 0);
-      vui->is_up = 0;
-
-      /*for (q = 0; q < VHOST_VRING_MAX_N; q++)
-         vhost_user_vring_close(&vui->vrings[q]); */
-
-      break;
-
-    case VHOST_USER_SET_MEM_TABLE:
-      DBG_SOCK ("if %d msg VHOST_USER_SET_MEM_TABLE nregions %d",
-		vui->hw_if_index, msg.memory.nregions);
-
-      if ((msg.memory.nregions < 1) ||
-	  (msg.memory.nregions > VHOST_MEMORY_MAX_NREGIONS))
-	{
-
-	  DBG_SOCK ("number of mem regions must be between 1 and %i",
-		    VHOST_MEMORY_MAX_NREGIONS);
-
-	  goto close_socket;
-	}
-
-      if (msg.memory.nregions != number_of_fds)
-	{
-	  DBG_SOCK ("each memory region must have FD");
-	  goto close_socket;
-	}
-      unmap_all_mem_regions (vui);
-      for (i = 0; i < msg.memory.nregions; i++)
-	{
-	  clib_memcpy (&(vui->regions[i]), &msg.memory.regions[i],
-		       sizeof (vhost_user_memory_region_t));
-
-	  long page_sz = get_huge_page_size (fds[i]);
-
-	  /* align size to page */
-	  ssize_t map_sz = (vui->regions[i].memory_size +
-			    vui->regions[i].mmap_offset +
-			    page_sz - 1) & ~(page_sz - 1);
-
-	  vui->region_mmap_addr[i] = mmap (0, map_sz, PROT_READ | PROT_WRITE,
-					   MAP_SHARED, fds[i], 0);
-	  vui->region_guest_addr_lo[i] = vui->regions[i].guest_phys_addr;
-	  vui->region_guest_addr_hi[i] = vui->regions[i].guest_phys_addr +
-	    vui->regions[i].memory_size;
-
-	  DBG_SOCK
-	    ("map memory region %d addr 0 len 0x%lx fd %d mapped 0x%lx "
-	     "page_sz 0x%x", i, map_sz, fds[i], vui->region_mmap_addr[i],
-	     page_sz);
-
-	  if (vui->region_mmap_addr[i] == MAP_FAILED)
-	    {
-	      clib_warning ("failed to map memory. errno is %d", errno);
-	      goto close_socket;
-	    }
-	  vui->region_mmap_addr[i] += vui->regions[i].mmap_offset;
-	  vui->region_mmap_fd[i] = fds[i];
-
-	  vui->nregions++;
-	}
-      break;
-
-    case VHOST_USER_SET_VRING_NUM:
-      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_NUM idx %d num %d",
-		vui->hw_if_index, msg.state.index, msg.state.num);
-
-      if ((msg.state.num > 32768) ||	/* maximum ring size is 32768 */
-	  (msg.state.num == 0) ||	/* it cannot be zero */
-	  ((msg.state.num - 1) & msg.state.num))	/* must be power of 2 */
-	goto close_socket;
-      vui->vrings[msg.state.index].qsz_mask = msg.state.num - 1;
-      break;
-
-    case VHOST_USER_SET_VRING_ADDR:
-      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_ADDR idx %d",
-		vui->hw_if_index, msg.state.index);
-
-      if (msg.state.index >= VHOST_VRING_MAX_N)
-	{
-	  DBG_SOCK ("invalid vring index VHOST_USER_SET_VRING_ADDR:"
-		    " %d >= %d", msg.state.index, VHOST_VRING_MAX_N);
-	  goto close_socket;
-	}
-
-      if (msg.size < sizeof (msg.addr))
-	{
-	  DBG_SOCK ("vhost message is too short (%d < %d)",
-		    msg.size, sizeof (msg.addr));
-	  goto close_socket;
-	}
-
-      vui->vrings[msg.state.index].desc = (vring_desc_t *)
-	map_user_mem (vui, msg.addr.desc_user_addr);
-      vui->vrings[msg.state.index].used = (vring_used_t *)
-	map_user_mem (vui, msg.addr.used_user_addr);
-      vui->vrings[msg.state.index].avail = (vring_avail_t *)
-	map_user_mem (vui, msg.addr.avail_user_addr);
-
-      if ((vui->vrings[msg.state.index].desc == NULL) ||
-	  (vui->vrings[msg.state.index].used == NULL) ||
-	  (vui->vrings[msg.state.index].avail == NULL))
-	{
-	  DBG_SOCK ("failed to map user memory for hw_if_index %d",
-		    vui->hw_if_index);
-	  goto close_socket;
-	}
-
-      vui->vrings[msg.state.index].log_guest_addr = msg.addr.log_guest_addr;
-      vui->vrings[msg.state.index].log_used =
-	(msg.addr.flags & (1 << VHOST_VRING_F_LOG)) ? 1 : 0;
-
-      /* Spec says: If VHOST_USER_F_PROTOCOL_FEATURES has not been negotiated,
-         the ring is initialized in an enabled state. */
-      if (!(vui->features & (1 << FEAT_VHOST_USER_F_PROTOCOL_FEATURES)))
-	{
-	  vui->vrings[msg.state.index].enabled = 1;
-	}
-
-      vui->vrings[msg.state.index].last_used_idx =
-	vui->vrings[msg.state.index].last_avail_idx =
-	vui->vrings[msg.state.index].used->idx;
-
-      /* tell driver that we don't want interrupts */
-      vui->vrings[msg.state.index].used->flags = VRING_USED_F_NO_NOTIFY;
-      break;
-
-    case VHOST_USER_SET_OWNER:
-      DBG_SOCK ("if %d msg VHOST_USER_SET_OWNER", vui->hw_if_index);
-      break;
-
-    case VHOST_USER_RESET_OWNER:
-      DBG_SOCK ("if %d msg VHOST_USER_RESET_OWNER", vui->hw_if_index);
-      break;
-
-    case VHOST_USER_SET_VRING_CALL:
-      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_CALL %d",
-		vui->hw_if_index, msg.u64);
-
-      q = (u8) (msg.u64 & 0xFF);
-
-      /* if there is old fd, delete and close it */
-      if (vui->vrings[q].callfd_idx != ~0)
-	{
-	  clib_file_t *uf = pool_elt_at_index (file_main.file_pool,
-					       vui->vrings[q].callfd_idx);
-	  clib_file_del (&file_main, uf);
-	  vui->vrings[q].callfd_idx = ~0;
-	}
-
-      if (!(msg.u64 & VHOST_USER_VRING_NOFD_MASK))
-	{
-	  if (number_of_fds != 1)
-	    {
-	      DBG_SOCK ("More than one fd received !");
-	      goto close_socket;
-	    }
-
-	  template.read_function = vhost_user_callfd_read_ready;
-	  template.file_descriptor = fds[0];
-	  template.private_data =
-	    ((vui - vhost_user_main.vhost_user_interfaces) << 8) + q;
-	  vui->vrings[q].callfd_idx = clib_file_add (&file_main, &template);
-	}
-      else
-	vui->vrings[q].callfd_idx = ~0;
-      break;
-
-    case VHOST_USER_SET_VRING_KICK:
-      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_KICK %d",
-		vui->hw_if_index, msg.u64);
-
-      q = (u8) (msg.u64 & 0xFF);
-
-      if (vui->vrings[q].kickfd_idx != ~0)
-	{
-	  clib_file_t *uf = pool_elt_at_index (file_main.file_pool,
-					       vui->vrings[q].kickfd_idx);
-	  clib_file_del (&file_main, uf);
-	  vui->vrings[q].kickfd_idx = ~0;
-	}
-
-      if (!(msg.u64 & VHOST_USER_VRING_NOFD_MASK))
-	{
-	  if (number_of_fds != 1)
-	    {
-	      DBG_SOCK ("More than one fd received !");
-	      goto close_socket;
-	    }
-
-	  template.read_function = vhost_user_kickfd_read_ready;
-	  template.file_descriptor = fds[0];
-	  template.private_data =
-	    (((uword) (vui - vhost_user_main.vhost_user_interfaces)) << 8) +
-	    q;
-	  vui->vrings[q].kickfd_idx = clib_file_add (&file_main, &template);
-	}
-      else
-	{
-	  //When no kickfd is set, the queue is initialized as started
-	  vui->vrings[q].kickfd_idx = ~0;
-	  vui->vrings[q].started = 1;
-	}
-
-      break;
-
-    case VHOST_USER_SET_VRING_ERR:
-      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_ERR %d",
-		vui->hw_if_index, msg.u64);
-
-      q = (u8) (msg.u64 & 0xFF);
-
-      if (vui->vrings[q].errfd != -1)
-	close (vui->vrings[q].errfd);
-
-      if (!(msg.u64 & VHOST_USER_VRING_NOFD_MASK))
-	{
-	  if (number_of_fds != 1)
-	    goto close_socket;
-
-	  vui->vrings[q].errfd = fds[0];
-	}
-      else
-	vui->vrings[q].errfd = -1;
-
-      break;
-
-    case VHOST_USER_SET_VRING_BASE:
-      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_BASE idx %d num %d",
-		vui->hw_if_index, msg.state.index, msg.state.num);
-
-      vui->vrings[msg.state.index].last_avail_idx = msg.state.num;
-      break;
-
-    case VHOST_USER_GET_VRING_BASE:
-      if (msg.state.index >= VHOST_VRING_MAX_N)
-	{
-	  DBG_SOCK ("invalid vring index VHOST_USER_GET_VRING_BASE:"
-		    " %d >= %d", msg.state.index, VHOST_VRING_MAX_N);
-	  goto close_socket;
-	}
-
-      /*
-       * Copy last_avail_idx from the vring before closing it because
-       * closing the vring also initializes the vring last_avail_idx
-       */
-      msg.state.num = vui->vrings[msg.state.index].last_avail_idx;
-      msg.flags |= 4;
-      msg.size = sizeof (msg.state);
-
-      /* Spec says: Client must [...] stop ring upon receiving VHOST_USER_GET_VRING_BASE. */
-      vhost_user_vring_close (vui, msg.state.index);
-      DBG_SOCK ("if %d msg VHOST_USER_GET_VRING_BASE idx %d num %d",
-		vui->hw_if_index, msg.state.index, msg.state.num);
-      break;
-
-    case VHOST_USER_NONE:
-      DBG_SOCK ("if %d msg VHOST_USER_NONE", vui->hw_if_index);
-
-      break;
-
-    case VHOST_USER_SET_LOG_BASE:
-      {
-	DBG_SOCK ("if %d msg VHOST_USER_SET_LOG_BASE", vui->hw_if_index);
-
-	if (msg.size != sizeof (msg.log))
-	  {
-	    DBG_SOCK
-	      ("invalid msg size for VHOST_USER_SET_LOG_BASE: %d instead of %d",
-	       msg.size, sizeof (msg.log));
-	    goto close_socket;
-	  }
-
-	if (!
-	    (vui->protocol_features & (1 << VHOST_USER_PROTOCOL_F_LOG_SHMFD)))
-	  {
-	    DBG_SOCK
-	      ("VHOST_USER_PROTOCOL_F_LOG_SHMFD not set but VHOST_USER_SET_LOG_BASE received");
-	    goto close_socket;
-	  }
-
-	fd = fds[0];
-	/* align size to page */
-	long page_sz = get_huge_page_size (fd);
-	ssize_t map_sz =
-	  (msg.log.size + msg.log.offset + page_sz - 1) & ~(page_sz - 1);
-
-	vui->log_base_addr = mmap (0, map_sz, PROT_READ | PROT_WRITE,
-				   MAP_SHARED, fd, 0);
-
-	DBG_SOCK
-	  ("map log region addr 0 len 0x%lx off 0x%lx fd %d mapped 0x%lx",
-	   map_sz, msg.log.offset, fd, vui->log_base_addr);
-
-	if (vui->log_base_addr == MAP_FAILED)
-	  {
-	    clib_warning ("failed to map memory. errno is %d", errno);
-	    goto close_socket;
-	  }
-
-	vui->log_base_addr += msg.log.offset;
-	vui->log_size = msg.log.size;
-
-	msg.flags |= 4;
-	msg.size = sizeof (msg.u64);
-
-	break;
-      }
-
-    case VHOST_USER_SET_LOG_FD:
-      DBG_SOCK ("if %d msg VHOST_USER_SET_LOG_FD", vui->hw_if_index);
-
-      break;
-
-    case VHOST_USER_GET_PROTOCOL_FEATURES:
-      msg.flags |= 4;
-      msg.u64 = (1 << VHOST_USER_PROTOCOL_F_LOG_SHMFD) |
-	(1 << VHOST_USER_PROTOCOL_F_MQ);
-      msg.size = sizeof (msg.u64);
-      DBG_SOCK
-	("if %d msg VHOST_USER_GET_PROTOCOL_FEATURES - reply 0x%016llx",
-	 vui->hw_if_index, msg.u64);
-      break;
-
-    case VHOST_USER_SET_PROTOCOL_FEATURES:
-      DBG_SOCK
-	("if %d msg VHOST_USER_SET_PROTOCOL_FEATURES features 0x%016llx",
-	 vui->hw_if_index, msg.u64);
-
-      vui->protocol_features = msg.u64;
-
-      break;
-
-    case VHOST_USER_GET_QUEUE_NUM:
-      msg.flags |= 4;
-      msg.u64 = VHOST_VRING_MAX_N;
-      msg.size = sizeof (msg.u64);
-      DBG_SOCK ("if %d msg VHOST_USER_GET_QUEUE_NUM - reply %d",
-		vui->hw_if_index, msg.u64);
-      break;
-
-    case VHOST_USER_SET_VRING_ENABLE:
-      DBG_SOCK ("if %d VHOST_USER_SET_VRING_ENABLE: %s queue %d",
-		vui->hw_if_index, msg.state.num ? "enable" : "disable",
-		msg.state.index);
-      if (msg.state.index >= VHOST_VRING_MAX_N)
-	{
-	  DBG_SOCK ("invalid vring index VHOST_USER_SET_VRING_ENABLE:"
-		    " %d >= %d", msg.state.index, VHOST_VRING_MAX_N);
-	  goto close_socket;
-	}
-
-      vui->vrings[msg.state.index].enabled = msg.state.num;
-      break;
-
-    default:
-      DBG_SOCK ("unknown vhost-user message %d received. closing socket",
-		msg.request);
-      goto close_socket;
-    }
-
-  /* if we need to reply */
-  if (msg.flags & 4)
-    {
-      n =
-	send (uf->file_descriptor, &msg, VHOST_USER_MSG_HDR_SZ + msg.size, 0);
-      if (n != (msg.size + VHOST_USER_MSG_HDR_SZ))
-	{
-	  DBG_SOCK ("could not send message response");
-	  goto close_socket;
-	}
-    }
-
-  vhost_user_update_iface_state (vui);
-  vlib_worker_thread_barrier_release (vlib_get_main ());
-  return 0;
-
-close_socket:
-  vhost_user_if_disconnect (vui);
-  vhost_user_update_iface_state (vui);
-  vlib_worker_thread_barrier_release (vlib_get_main ());
-  return 0;
-}
-
-static clib_error_t *
-vhost_user_socket_error (clib_file_t * uf)
-{
-  vlib_main_t *vm = vlib_get_main ();
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui =
-    pool_elt_at_index (vum->vhost_user_interfaces, uf->private_data);
-
-  DBG_SOCK ("socket error on if %d", vui->sw_if_index);
-  vlib_worker_thread_barrier_sync (vm);
-  vhost_user_if_disconnect (vui);
-  vhost_user_rx_thread_placement ();
-  vlib_worker_thread_barrier_release (vm);
-  return 0;
-}
-
-static clib_error_t *
-vhost_user_socksvr_accept_ready (clib_file_t * uf)
-{
-  int client_fd, client_len;
-  struct sockaddr_un client;
-  clib_file_t template = { 0 };
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui;
-
-  vui = pool_elt_at_index (vum->vhost_user_interfaces, uf->private_data);
-
-  client_len = sizeof (client);
-  client_fd = accept (uf->file_descriptor,
-		      (struct sockaddr *) &client,
-		      (socklen_t *) & client_len);
-
-  if (client_fd < 0)
-    return clib_error_return_unix (0, "accept");
-
-  if (vui->clib_file_index != ~0)
-    {
-      DBG_SOCK ("Close client socket for vhost interface %d, fd %d",
-		vui->sw_if_index, UNIX_GET_FD (vui->clib_file_index));
-      clib_file_del (&file_main, file_main.file_pool + vui->clib_file_index);
-    }
-
-  DBG_SOCK ("New client socket for vhost interface %d, fd %d",
-	    vui->sw_if_index, client_fd);
-  template.read_function = vhost_user_socket_read;
-  template.error_function = vhost_user_socket_error;
-  template.file_descriptor = client_fd;
-  template.private_data = vui - vhost_user_main.vhost_user_interfaces;
-  vui->clib_file_index = clib_file_add (&file_main, &template);
-  return 0;
-}
-
-static clib_error_t *
-vhost_user_init (vlib_main_t * vm)
-{
-  clib_error_t *error;
-  vhost_user_main_t *vum = &vhost_user_main;
-  vlib_thread_main_t *tm = vlib_get_thread_main ();
-
-  error = vlib_call_init_function (vm, ip4_init);
-  if (error)
-    return error;
-
-  vum->coalesce_frames = 32;
-  vum->coalesce_time = 1e-3;
-
-  vec_validate (vum->cpus, tm->n_vlib_mains - 1);
-
-  vhost_cpu_t *cpu;
-  vec_foreach (cpu, vum->cpus)
-  {
-    /* This is actually not necessary as validate already zeroes it
-     * Just keeping the loop here for later because I am lazy. */
-    cpu->rx_buffers_len = 0;
-  }
-
-  vum->random = random_default_seed ();
-
-  mhash_init_c_string (&vum->if_index_by_sock_name, sizeof (uword));
-
-  return 0;
-}
-
-VLIB_INIT_FUNCTION (vhost_user_init);
-
-static u8 *
-format_vhost_trace (u8 * s, va_list * va)
-{
-  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
-  CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *);
-  CLIB_UNUSED (vnet_main_t * vnm) = vnet_get_main ();
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_trace_t *t = va_arg (*va, vhost_trace_t *);
-  vhost_user_intf_t *vui = pool_elt_at_index (vum->vhost_user_interfaces,
-					      t->device_index);
-
-  vnet_sw_interface_t *sw = vnet_get_sw_interface (vnm, vui->sw_if_index);
-
-  u32 indent = format_get_indent (s);
-
-  s = format (s, "%U %U queue %d\n", format_white_space, indent,
-	      format_vnet_sw_interface_name, vnm, sw, t->qid);
-
-  s = format (s, "%U virtio flags:\n", format_white_space, indent);
-#define _(n,i,st) \
-	  if (t->virtio_ring_flags & (1 << VIRTIO_TRACE_F_##n)) \
-	    s = format (s, "%U  %s %s\n", format_white_space, indent, #n, st);
-  foreach_virtio_trace_flags
-#undef _
-    s = format (s, "%U virtio_net_hdr first_desc_len %u\n",
-		format_white_space, indent, t->first_desc_len);
-
-  s = format (s, "%U   flags 0x%02x gso_type %u\n",
-	      format_white_space, indent,
-	      t->hdr.hdr.flags, t->hdr.hdr.gso_type);
-
-  if (vui->virtio_net_hdr_sz == 12)
-    s = format (s, "%U   num_buff %u",
-		format_white_space, indent, t->hdr.num_buffers);
-
-  return s;
-}
-
-void
-vhost_user_rx_trace (vhost_trace_t * t,
-		     vhost_user_intf_t * vui, u16 qid,
-		     vlib_buffer_t * b, vhost_user_vring_t * txvq)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  u32 last_avail_idx = txvq->last_avail_idx;
-  u32 desc_current = txvq->avail->ring[last_avail_idx & txvq->qsz_mask];
-  vring_desc_t *hdr_desc = 0;
-  virtio_net_hdr_mrg_rxbuf_t *hdr;
-  u32 hint = 0;
-
-  memset (t, 0, sizeof (*t));
-  t->device_index = vui - vum->vhost_user_interfaces;
-  t->qid = qid;
-
-  hdr_desc = &txvq->desc[desc_current];
-  if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT)
-    {
-      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_INDIRECT;
-      /* Header is the first here */
-      hdr_desc = map_guest_mem (vui, txvq->desc[desc_current].addr, &hint);
-    }
-  if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT)
-    {
-      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_SIMPLE_CHAINED;
-    }
-  if (!(txvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT) &&
-      !(txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT))
-    {
-      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_SINGLE_DESC;
-    }
-
-  t->first_desc_len = hdr_desc ? hdr_desc->len : 0;
-
-  if (!hdr_desc || !(hdr = map_guest_mem (vui, hdr_desc->addr, &hint)))
-    {
-      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_MAP_ERROR;
-    }
-  else
-    {
-      u32 len = vui->virtio_net_hdr_sz;
-      memcpy (&t->hdr, hdr, len > hdr_desc->len ? hdr_desc->len : len);
-    }
-}
-
-static inline void
-vhost_user_send_call (vlib_main_t * vm, vhost_user_vring_t * vq)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  u64 x = 1;
-  int fd = UNIX_GET_FD (vq->callfd_idx);
-  int rv;
-
-  rv = write (fd, &x, sizeof (x));
-  if (rv <= 0)
-    {
-      clib_unix_warning
-	("Error: Could not write to unix socket for callfd %d", fd);
-      return;
-    }
-
-  vq->n_since_last_int = 0;
-  vq->int_deadline = vlib_time_now (vm) + vum->coalesce_time;
-}
-
-static_always_inline u32
-vhost_user_input_copy (vhost_user_intf_t * vui, vhost_copy_t * cpy,
-		       u16 copy_len, u32 * map_hint)
-{
-  void *src0, *src1, *src2, *src3;
-  if (PREDICT_TRUE (copy_len >= 4))
-    {
-      if (PREDICT_FALSE (!(src2 = map_guest_mem (vui, cpy[0].src, map_hint))))
-	return 1;
-      if (PREDICT_FALSE (!(src3 = map_guest_mem (vui, cpy[1].src, map_hint))))
-	return 1;
-
-      while (PREDICT_TRUE (copy_len >= 4))
-	{
-	  src0 = src2;
-	  src1 = src3;
-
-	  if (PREDICT_FALSE
-	      (!(src2 = map_guest_mem (vui, cpy[2].src, map_hint))))
-	    return 1;
-	  if (PREDICT_FALSE
-	      (!(src3 = map_guest_mem (vui, cpy[3].src, map_hint))))
-	    return 1;
-
-	  CLIB_PREFETCH (src2, 64, LOAD);
-	  CLIB_PREFETCH (src3, 64, LOAD);
-
-	  clib_memcpy ((void *) cpy[0].dst, src0, cpy[0].len);
-	  clib_memcpy ((void *) cpy[1].dst, src1, cpy[1].len);
-	  copy_len -= 2;
-	  cpy += 2;
-	}
-    }
-  while (copy_len)
-    {
-      if (PREDICT_FALSE (!(src0 = map_guest_mem (vui, cpy->src, map_hint))))
-	return 1;
-      clib_memcpy ((void *) cpy->dst, src0, cpy->len);
-      copy_len -= 1;
-      cpy += 1;
-    }
-  return 0;
-}
-
-/**
- * Try to discard packets from the tx ring (VPP RX path).
- * Returns the number of discarded packets.
- */
-u32
-vhost_user_rx_discard_packet (vlib_main_t * vm,
-			      vhost_user_intf_t * vui,
-			      vhost_user_vring_t * txvq, u32 discard_max)
-{
-  /*
-   * On the RX side, each packet corresponds to one descriptor
-   * (it is the same whether it is a shallow descriptor, chained, or indirect).
-   * Therefore, discarding a packet is like discarding a descriptor.
-   */
-  u32 discarded_packets = 0;
-  u32 avail_idx = txvq->avail->idx;
-  while (discarded_packets != discard_max)
-    {
-      if (avail_idx == txvq->last_avail_idx)
-	goto out;
-
-      u16 desc_chain_head =
-	txvq->avail->ring[txvq->last_avail_idx & txvq->qsz_mask];
-      txvq->last_avail_idx++;
-      txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].id =
-	desc_chain_head;
-      txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].len = 0;
-      vhost_user_log_dirty_ring (vui, txvq,
-				 ring[txvq->last_used_idx & txvq->qsz_mask]);
-      txvq->last_used_idx++;
-      discarded_packets++;
-    }
-
-out:
-  CLIB_MEMORY_BARRIER ();
-  txvq->used->idx = txvq->last_used_idx;
-  vhost_user_log_dirty_ring (vui, txvq, idx);
-  return discarded_packets;
-}
-
-/*
- * In case of overflow, we need to rewind the array of allocated buffers.
- */
-static void
-vhost_user_input_rewind_buffers (vlib_main_t * vm,
-				 vhost_cpu_t * cpu, vlib_buffer_t * b_head)
-{
-  u32 bi_current = cpu->rx_buffers[cpu->rx_buffers_len];
-  vlib_buffer_t *b_current = vlib_get_buffer (vm, bi_current);
-  b_current->current_length = 0;
-  b_current->flags = 0;
-  while (b_current != b_head)
-    {
-      cpu->rx_buffers_len++;
-      bi_current = cpu->rx_buffers[cpu->rx_buffers_len];
-      b_current = vlib_get_buffer (vm, bi_current);
-      b_current->current_length = 0;
-      b_current->flags = 0;
-    }
-  cpu->rx_buffers_len++;
-}
-
-static u32
-vhost_user_if_input (vlib_main_t * vm,
-		     vhost_user_main_t * vum,
-		     vhost_user_intf_t * vui,
-		     u16 qid, vlib_node_runtime_t * node,
-		     vnet_hw_interface_rx_mode mode)
-{
-  vhost_user_vring_t *txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)];
-  u16 n_rx_packets = 0;
-  u32 n_rx_bytes = 0;
-  u16 n_left;
-  u32 n_left_to_next, *to_next;
-  u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
-  u32 n_trace = vlib_get_trace_count (vm, node);
-  u32 map_hint = 0;
-  u16 thread_index = vlib_get_thread_index ();
-  u16 copy_len = 0;
-
-  {
-    /* do we have pending interrupts ? */
-    vhost_user_vring_t *rxvq = &vui->vrings[VHOST_VRING_IDX_RX (qid)];
-    f64 now = vlib_time_now (vm);
-
-    if ((txvq->n_since_last_int) && (txvq->int_deadline < now))
-      vhost_user_send_call (vm, txvq);
-
-    if ((rxvq->n_since_last_int) && (rxvq->int_deadline < now))
-      vhost_user_send_call (vm, rxvq);
-  }
-
-  /*
-   * For adaptive mode, it is optimized to reduce interrupts.
-   * If the scheduler switches the input node to polling due
-   * to burst of traffic, we tell the driver no interrupt.
-   * When the traffic subsides, the scheduler switches the node back to
-   * interrupt mode. We must tell the driver we want interrupt.
-   */
-  if (PREDICT_FALSE (mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE))
-    {
-      if ((node->flags &
-	   VLIB_NODE_FLAG_SWITCH_FROM_POLLING_TO_INTERRUPT_MODE) ||
-	  !(node->flags &
-	    VLIB_NODE_FLAG_SWITCH_FROM_INTERRUPT_TO_POLLING_MODE))
-	/* Tell driver we want notification */
-	txvq->used->flags = 0;
-      else
-	/* Tell driver we don't want notification */
-	txvq->used->flags = VRING_USED_F_NO_NOTIFY;
-    }
-
-  if (PREDICT_FALSE (txvq->avail->flags & 0xFFFE))
-    return 0;
-
-  n_left = (u16) (txvq->avail->idx - txvq->last_avail_idx);
-
-  /* nothing to do */
-  if (PREDICT_FALSE (n_left == 0))
-    return 0;
-
-  if (PREDICT_FALSE (!vui->admin_up || !(txvq->enabled)))
-    {
-      /*
-       * Discard input packet if interface is admin down or vring is not
-       * enabled.
-       * "For example, for a networking device, in the disabled state
-       * client must not supply any new RX packets, but must process
-       * and discard any TX packets."
-       */
-      vhost_user_rx_discard_packet (vm, vui, txvq,
-				    VHOST_USER_DOWN_DISCARD_COUNT);
-      return 0;
-    }
-
-  if (PREDICT_FALSE (n_left == (txvq->qsz_mask + 1)))
-    {
-      /*
-       * Informational error logging when VPP is not
-       * receiving packets fast enough.
-       */
-      vlib_error_count (vm, node->node_index,
-			VHOST_USER_INPUT_FUNC_ERROR_FULL_RX_QUEUE, 1);
-    }
-
-  if (n_left > VLIB_FRAME_SIZE)
-    n_left = VLIB_FRAME_SIZE;
-
-  /*
-   * For small packets (<2kB), we will not need more than one vlib buffer
-   * per packet. In case packets are bigger, we will just yeld at some point
-   * in the loop and come back later. This is not an issue as for big packet,
-   * processing cost really comes from the memory copy.
-   * The assumption is that big packets will fit in 40 buffers.
-   */
-  if (PREDICT_FALSE (vum->cpus[thread_index].rx_buffers_len < n_left + 1 ||
-		     vum->cpus[thread_index].rx_buffers_len < 40))
-    {
-      u32 curr_len = vum->cpus[thread_index].rx_buffers_len;
-      vum->cpus[thread_index].rx_buffers_len +=
-	vlib_buffer_alloc_from_free_list (vm,
-					  vum->cpus[thread_index].rx_buffers +
-					  curr_len,
-					  VHOST_USER_RX_BUFFERS_N - curr_len,
-					  VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
-
-      if (PREDICT_FALSE
-	  (vum->cpus[thread_index].rx_buffers_len <
-	   VHOST_USER_RX_BUFFER_STARVATION))
-	{
-	  /* In case of buffer starvation, discard some packets from the queue
-	   * and log the event.
-	   * We keep doing best effort for the remaining packets. */
-	  u32 flush = (n_left + 1 > vum->cpus[thread_index].rx_buffers_len) ?
-	    n_left + 1 - vum->cpus[thread_index].rx_buffers_len : 1;
-	  flush = vhost_user_rx_discard_packet (vm, vui, txvq, flush);
-
-	  n_left -= flush;
-	  vlib_increment_simple_counter (vnet_main.
-					 interface_main.sw_if_counters +
-					 VNET_INTERFACE_COUNTER_DROP,
-					 vlib_get_thread_index (),
-					 vui->sw_if_index, flush);
-
-	  vlib_error_count (vm, vhost_user_input_node.index,
-			    VHOST_USER_INPUT_FUNC_ERROR_NO_BUFFER, flush);
-	}
-    }
-
-  while (n_left > 0)
-    {
-      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
-
-      while (n_left > 0 && n_left_to_next > 0)
-	{
-	  vlib_buffer_t *b_head, *b_current;
-	  u32 bi_current;
-	  u16 desc_current;
-	  u32 desc_data_offset;
-	  vring_desc_t *desc_table = txvq->desc;
-
-	  if (PREDICT_FALSE (vum->cpus[thread_index].rx_buffers_len <= 1))
-	    {
-	      /* Not enough rx_buffers
-	       * Note: We yeld on 1 so we don't need to do an additional
-	       * check for the next buffer prefetch.
-	       */
-	      n_left = 0;
-	      break;
-	    }
-
-	  desc_current =
-	    txvq->avail->ring[txvq->last_avail_idx & txvq->qsz_mask];
-	  vum->cpus[thread_index].rx_buffers_len--;
-	  bi_current = (vum->cpus[thread_index].rx_buffers)
-	    [vum->cpus[thread_index].rx_buffers_len];
-	  b_head = b_current = vlib_get_buffer (vm, bi_current);
-	  to_next[0] = bi_current;	//We do that now so we can forget about bi_current
-	  to_next++;
-	  n_left_to_next--;
-
-	  vlib_prefetch_buffer_with_index (vm,
-					   (vum->
-					    cpus[thread_index].rx_buffers)
-					   [vum->cpus[thread_index].
-					    rx_buffers_len - 1], LOAD);
-
-	  /* Just preset the used descriptor id and length for later */
-	  txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].id =
-	    desc_current;
-	  txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].len = 0;
-	  vhost_user_log_dirty_ring (vui, txvq,
-				     ring[txvq->last_used_idx &
-					  txvq->qsz_mask]);
-
-	  /* The buffer should already be initialized */
-	  b_head->total_length_not_including_first_buffer = 0;
-	  b_head->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
-
-	  if (PREDICT_FALSE (n_trace))
-	    {
-	      //TODO: next_index is not exactly known at that point
-	      vlib_trace_buffer (vm, node, next_index, b_head,
-				 /* follow_chain */ 0);
-	      vhost_trace_t *t0 =
-		vlib_add_trace (vm, node, b_head, sizeof (t0[0]));
-	      vhost_user_rx_trace (t0, vui, qid, b_head, txvq);
-	      n_trace--;
-	      vlib_set_trace_count (vm, node, n_trace);
-	    }
-
-	  /* This depends on the setup but is very consistent
-	   * So I think the CPU branch predictor will make a pretty good job
-	   * at optimizing the decision. */
-	  if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT)
-	    {
-	      desc_table = map_guest_mem (vui, txvq->desc[desc_current].addr,
-					  &map_hint);
-	      desc_current = 0;
-	      if (PREDICT_FALSE (desc_table == 0))
-		{
-		  vlib_error_count (vm, node->node_index,
-				    VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL, 1);
-		  goto out;
-		}
-	    }
-
-	  if (PREDICT_TRUE (vui->is_any_layout) ||
-	      (!(desc_table[desc_current].flags & VIRTQ_DESC_F_NEXT)))
-	    {
-	      /* ANYLAYOUT or single buffer */
-	      desc_data_offset = vui->virtio_net_hdr_sz;
-	    }
-	  else
-	    {
-	      /* CSR case without ANYLAYOUT, skip 1st buffer */
-	      desc_data_offset = desc_table[desc_current].len;
-	    }
-
-	  while (1)
-	    {
-	      /* Get more input if necessary. Or end of packet. */
-	      if (desc_data_offset == desc_table[desc_current].len)
-		{
-		  if (PREDICT_FALSE (desc_table[desc_current].flags &
-				     VIRTQ_DESC_F_NEXT))
-		    {
-		      desc_current = desc_table[desc_current].next;
-		      desc_data_offset = 0;
-		    }
-		  else
-		    {
-		      goto out;
-		    }
-		}
-
-	      /* Get more output if necessary. Or end of packet. */
-	      if (PREDICT_FALSE
-		  (b_current->current_length == VLIB_BUFFER_DATA_SIZE))
-		{
-		  if (PREDICT_FALSE
-		      (vum->cpus[thread_index].rx_buffers_len == 0))
-		    {
-		      /* Cancel speculation */
-		      to_next--;
-		      n_left_to_next++;
-
-		      /*
-		       * Checking if there are some left buffers.
-		       * If not, just rewind the used buffers and stop.
-		       * Note: Scheduled copies are not cancelled. This is
-		       * not an issue as they would still be valid. Useless,
-		       * but valid.
-		       */
-		      vhost_user_input_rewind_buffers (vm,
-						       &vum->cpus
-						       [thread_index],
-						       b_head);
-		      n_left = 0;
-		      goto stop;
-		    }
-
-		  /* Get next output */
-		  vum->cpus[thread_index].rx_buffers_len--;
-		  u32 bi_next =
-		    (vum->cpus[thread_index].rx_buffers)[vum->cpus
-							 [thread_index].rx_buffers_len];
-		  b_current->next_buffer = bi_next;
-		  b_current->flags |= VLIB_BUFFER_NEXT_PRESENT;
-		  bi_current = bi_next;
-		  b_current = vlib_get_buffer (vm, bi_current);
-		}
-
-	      /* Prepare a copy order executed later for the data */
-	      vhost_copy_t *cpy = &vum->cpus[thread_index].copy[copy_len];
-	      copy_len++;
-	      u32 desc_data_l =
-		desc_table[desc_current].len - desc_data_offset;
-	      cpy->len = VLIB_BUFFER_DATA_SIZE - b_current->current_length;
-	      cpy->len = (cpy->len > desc_data_l) ? desc_data_l : cpy->len;
-	      cpy->dst = (uword) (vlib_buffer_get_current (b_current) +
-				  b_current->current_length);
-	      cpy->src = desc_table[desc_current].addr + desc_data_offset;
-
-	      desc_data_offset += cpy->len;
-
-	      b_current->current_length += cpy->len;
-	      b_head->total_length_not_including_first_buffer += cpy->len;
-	    }
-
-	out:
-	  CLIB_PREFETCH (&n_left, sizeof (n_left), LOAD);
-
-	  n_rx_bytes += b_head->total_length_not_including_first_buffer;
-	  n_rx_packets++;
-
-	  b_head->total_length_not_including_first_buffer -=
-	    b_head->current_length;
-
-	  /* consume the descriptor and return it as used */
-	  txvq->last_avail_idx++;
-	  txvq->last_used_idx++;
-
-	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b_head);
-
-	  vnet_buffer (b_head)->sw_if_index[VLIB_RX] = vui->sw_if_index;
-	  vnet_buffer (b_head)->sw_if_index[VLIB_TX] = (u32) ~ 0;
-	  b_head->error = 0;
-
-	  {
-	    u32 next0 = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
-
-	    /* redirect if feature path enabled */
-	    vnet_feature_start_device_input_x1 (vui->sw_if_index, &next0,
-						b_head);
-
-	    u32 bi = to_next[-1];	//Cannot use to_next[-1] in the macro
-	    vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
-					     to_next, n_left_to_next,
-					     bi, next0);
-	  }
-
-	  n_left--;
-
-	  /*
-	   * Although separating memory copies from virtio ring parsing
-	   * is beneficial, we can offer to perform the copies from time
-	   * to time in order to free some space in the ring.
-	   */
-	  if (PREDICT_FALSE (copy_len >= VHOST_USER_RX_COPY_THRESHOLD))
-	    {
-	      if (PREDICT_FALSE
-		  (vhost_user_input_copy (vui, vum->cpus[thread_index].copy,
-					  copy_len, &map_hint)))
-		{
-		  vlib_error_count (vm, node->node_index,
-				    VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL, 1);
-		}
-	      copy_len = 0;
-
-	      /* give buffers back to driver */
-	      CLIB_MEMORY_BARRIER ();
-	      txvq->used->idx = txvq->last_used_idx;
-	      vhost_user_log_dirty_ring (vui, txvq, idx);
-	    }
-	}
-    stop:
-      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
-    }
-
-  /* Do the memory copies */
-  if (PREDICT_FALSE
-      (vhost_user_input_copy (vui, vum->cpus[thread_index].copy,
-			      copy_len, &map_hint)))
-    {
-      vlib_error_count (vm, node->node_index,
-			VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL, 1);
-    }
-
-  /* give buffers back to driver */
-  CLIB_MEMORY_BARRIER ();
-  txvq->used->idx = txvq->last_used_idx;
-  vhost_user_log_dirty_ring (vui, txvq, idx);
-
-  /* interrupt (call) handling */
-  if ((txvq->callfd_idx != ~0) &&
-      !(txvq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
-    {
-      txvq->n_since_last_int += n_rx_packets;
-
-      if (txvq->n_since_last_int > vum->coalesce_frames)
-	vhost_user_send_call (vm, txvq);
-    }
-
-  /* increase rx counters */
-  vlib_increment_combined_counter
-    (vnet_main.interface_main.combined_sw_if_counters
-     + VNET_INTERFACE_COUNTER_RX,
-     vlib_get_thread_index (), vui->sw_if_index, n_rx_packets, n_rx_bytes);
-
-  vnet_device_increment_rx_packets (thread_index, n_rx_packets);
-
-  return n_rx_packets;
-}
-
-static uword
-vhost_user_input (vlib_main_t * vm,
-		  vlib_node_runtime_t * node, vlib_frame_t * f)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  uword n_rx_packets = 0;
-  vhost_user_intf_t *vui;
-  vnet_device_input_runtime_t *rt =
-    (vnet_device_input_runtime_t *) node->runtime_data;
-  vnet_device_and_queue_t *dq;
-
-  vec_foreach (dq, rt->devices_and_queues)
-  {
-    if (clib_smp_swap (&dq->interrupt_pending, 0) ||
-	(node->state == VLIB_NODE_STATE_POLLING))
-      {
-	vui =
-	  pool_elt_at_index (vum->vhost_user_interfaces, dq->dev_instance);
-	n_rx_packets = vhost_user_if_input (vm, vum, vui, dq->queue_id, node,
-					    dq->mode);
-      }
-  }
-
-  return n_rx_packets;
-}
-
-/* *INDENT-OFF* */
-VLIB_REGISTER_NODE (vhost_user_input_node) = {
-  .function = vhost_user_input,
-  .type = VLIB_NODE_TYPE_INPUT,
-  .name = "vhost-user-input",
-  .sibling_of = "device-input",
-
-  /* Will be enabled if/when hardware is detected. */
-  .state = VLIB_NODE_STATE_DISABLED,
-
-  .format_buffer = format_ethernet_header_with_length,
-  .format_trace = format_vhost_trace,
-
-  .n_errors = VHOST_USER_INPUT_FUNC_N_ERROR,
-  .error_strings = vhost_user_input_func_error_strings,
-};
-
-VLIB_NODE_FUNCTION_MULTIARCH (vhost_user_input_node, vhost_user_input)
-/* *INDENT-ON* */
-
-
-void
-vhost_user_tx_trace (vhost_trace_t * t,
-		     vhost_user_intf_t * vui, u16 qid,
-		     vlib_buffer_t * b, vhost_user_vring_t * rxvq)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  u32 last_avail_idx = rxvq->last_avail_idx;
-  u32 desc_current = rxvq->avail->ring[last_avail_idx & rxvq->qsz_mask];
-  vring_desc_t *hdr_desc = 0;
-  u32 hint = 0;
-
-  memset (t, 0, sizeof (*t));
-  t->device_index = vui - vum->vhost_user_interfaces;
-  t->qid = qid;
-
-  hdr_desc = &rxvq->desc[desc_current];
-  if (rxvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT)
-    {
-      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_INDIRECT;
-      /* Header is the first here */
-      hdr_desc = map_guest_mem (vui, rxvq->desc[desc_current].addr, &hint);
-    }
-  if (rxvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT)
-    {
-      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_SIMPLE_CHAINED;
-    }
-  if (!(rxvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT) &&
-      !(rxvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT))
-    {
-      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_SINGLE_DESC;
-    }
-
-  t->first_desc_len = hdr_desc ? hdr_desc->len : 0;
-}
-
-static_always_inline u32
-vhost_user_tx_copy (vhost_user_intf_t * vui, vhost_copy_t * cpy,
-		    u16 copy_len, u32 * map_hint)
-{
-  void *dst0, *dst1, *dst2, *dst3;
-  if (PREDICT_TRUE (copy_len >= 4))
-    {
-      if (PREDICT_FALSE (!(dst2 = map_guest_mem (vui, cpy[0].dst, map_hint))))
-	return 1;
-      if (PREDICT_FALSE (!(dst3 = map_guest_mem (vui, cpy[1].dst, map_hint))))
-	return 1;
-      while (PREDICT_TRUE (copy_len >= 4))
-	{
-	  dst0 = dst2;
-	  dst1 = dst3;
-
-	  if (PREDICT_FALSE
-	      (!(dst2 = map_guest_mem (vui, cpy[2].dst, map_hint))))
-	    return 1;
-	  if (PREDICT_FALSE
-	      (!(dst3 = map_guest_mem (vui, cpy[3].dst, map_hint))))
-	    return 1;
-
-	  CLIB_PREFETCH ((void *) cpy[2].src, 64, LOAD);
-	  CLIB_PREFETCH ((void *) cpy[3].src, 64, LOAD);
-
-	  clib_memcpy (dst0, (void *) cpy[0].src, cpy[0].len);
-	  clib_memcpy (dst1, (void *) cpy[1].src, cpy[1].len);
-
-	  vhost_user_log_dirty_pages_2 (vui, cpy[0].dst, cpy[0].len, 1);
-	  vhost_user_log_dirty_pages_2 (vui, cpy[1].dst, cpy[1].len, 1);
-	  copy_len -= 2;
-	  cpy += 2;
-	}
-    }
-  while (copy_len)
-    {
-      if (PREDICT_FALSE (!(dst0 = map_guest_mem (vui, cpy->dst, map_hint))))
-	return 1;
-      clib_memcpy (dst0, (void *) cpy->src, cpy->len);
-      vhost_user_log_dirty_pages_2 (vui, cpy->dst, cpy->len, 1);
-      copy_len -= 1;
-      cpy += 1;
-    }
-  return 0;
-}
-
-
-static uword
-vhost_user_tx (vlib_main_t * vm,
-	       vlib_node_runtime_t * node, vlib_frame_t * frame)
-{
-  u32 *buffers = vlib_frame_args (frame);
-  u32 n_left = frame->n_vectors;
-  vhost_user_main_t *vum = &vhost_user_main;
-  vnet_interface_output_runtime_t *rd = (void *) node->runtime_data;
-  vhost_user_intf_t *vui =
-    pool_elt_at_index (vum->vhost_user_interfaces, rd->dev_instance);
-  u32 qid = ~0;
-  vhost_user_vring_t *rxvq;
-  u8 error;
-  u32 thread_index = vlib_get_thread_index ();
-  u32 map_hint = 0;
-  u8 retry = 8;
-  u16 copy_len;
-  u16 tx_headers_len;
-
-  if (PREDICT_FALSE (!vui->admin_up))
-    {
-      error = VHOST_USER_TX_FUNC_ERROR_DOWN;
-      goto done3;
-    }
-
-  if (PREDICT_FALSE (!vui->is_up))
-    {
-      error = VHOST_USER_TX_FUNC_ERROR_NOT_READY;
-      goto done3;
-    }
-
-  qid =
-    VHOST_VRING_IDX_RX (*vec_elt_at_index
-			(vui->per_cpu_tx_qid, thread_index));
-  rxvq = &vui->vrings[qid];
-  if (PREDICT_FALSE (vui->use_tx_spinlock))
-    vhost_user_vring_lock (vui, qid);
-
-retry:
-  error = VHOST_USER_TX_FUNC_ERROR_NONE;
-  tx_headers_len = 0;
-  copy_len = 0;
-  while (n_left > 0)
-    {
-      vlib_buffer_t *b0, *current_b0;
-      u16 desc_head, desc_index, desc_len;
-      vring_desc_t *desc_table;
-      uword buffer_map_addr;
-      u32 buffer_len;
-      u16 bytes_left;
-
-      if (PREDICT_TRUE (n_left > 1))
-	vlib_prefetch_buffer_with_index (vm, buffers[1], LOAD);
-
-      b0 = vlib_get_buffer (vm, buffers[0]);
-
-      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
-	{
-	  vum->cpus[thread_index].current_trace =
-	    vlib_add_trace (vm, node, b0,
-			    sizeof (*vum->cpus[thread_index].current_trace));
-	  vhost_user_tx_trace (vum->cpus[thread_index].current_trace,
-			       vui, qid / 2, b0, rxvq);
-	}
-
-      if (PREDICT_FALSE (rxvq->last_avail_idx == rxvq->avail->idx))
-	{
-	  error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF;
-	  goto done;
-	}
-
-      desc_table = rxvq->desc;
-      desc_head = desc_index =
-	rxvq->avail->ring[rxvq->last_avail_idx & rxvq->qsz_mask];
-
-      /* Go deeper in case of indirect descriptor
-       * I don't know of any driver providing indirect for RX. */
-      if (PREDICT_FALSE (rxvq->desc[desc_head].flags & VIRTQ_DESC_F_INDIRECT))
-	{
-	  if (PREDICT_FALSE
-	      (rxvq->desc[desc_head].len < sizeof (vring_desc_t)))
-	    {
-	      error = VHOST_USER_TX_FUNC_ERROR_INDIRECT_OVERFLOW;
-	      goto done;
-	    }
-	  if (PREDICT_FALSE
-	      (!(desc_table =
-		 map_guest_mem (vui, rxvq->desc[desc_index].addr,
-				&map_hint))))
-	    {
-	      error = VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL;
-	      goto done;
-	    }
-	  desc_index = 0;
-	}
-
-      desc_len = vui->virtio_net_hdr_sz;
-      buffer_map_addr = desc_table[desc_index].addr;
-      buffer_len = desc_table[desc_index].len;
-
-      {
-	// Get a header from the header array
-	virtio_net_hdr_mrg_rxbuf_t *hdr =
-	  &vum->cpus[thread_index].tx_headers[tx_headers_len];
-	tx_headers_len++;
-	hdr->hdr.flags = 0;
-	hdr->hdr.gso_type = 0;
-	hdr->num_buffers = 1;	//This is local, no need to check
-
-	// Prepare a copy order executed later for the header
-	vhost_copy_t *cpy = &vum->cpus[thread_index].copy[copy_len];
-	copy_len++;
-	cpy->len = vui->virtio_net_hdr_sz;
-	cpy->dst = buffer_map_addr;
-	cpy->src = (uword) hdr;
-      }
-
-      buffer_map_addr += vui->virtio_net_hdr_sz;
-      buffer_len -= vui->virtio_net_hdr_sz;
-      bytes_left = b0->current_length;
-      current_b0 = b0;
-      while (1)
-	{
-	  if (buffer_len == 0)
-	    {			//Get new output
-	      if (desc_table[desc_index].flags & VIRTQ_DESC_F_NEXT)
-		{
-		  //Next one is chained
-		  desc_index = desc_table[desc_index].next;
-		  buffer_map_addr = desc_table[desc_index].addr;
-		  buffer_len = desc_table[desc_index].len;
-		}
-	      else if (vui->virtio_net_hdr_sz == 12)	//MRG is available
-		{
-		  virtio_net_hdr_mrg_rxbuf_t *hdr =
-		    &vum->cpus[thread_index].tx_headers[tx_headers_len - 1];
-
-		  //Move from available to used buffer
-		  rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].id =
-		    desc_head;
-		  rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].len =
-		    desc_len;
-		  vhost_user_log_dirty_ring (vui, rxvq,
-					     ring[rxvq->last_used_idx &
-						  rxvq->qsz_mask]);
-
-		  rxvq->last_avail_idx++;
-		  rxvq->last_used_idx++;
-		  hdr->num_buffers++;
-		  desc_len = 0;
-
-		  if (PREDICT_FALSE
-		      (rxvq->last_avail_idx == rxvq->avail->idx))
-		    {
-		      //Dequeue queued descriptors for this packet
-		      rxvq->last_used_idx -= hdr->num_buffers - 1;
-		      rxvq->last_avail_idx -= hdr->num_buffers - 1;
-		      error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF;
-		      goto done;
-		    }
-
-		  desc_table = rxvq->desc;
-		  desc_head = desc_index =
-		    rxvq->avail->ring[rxvq->last_avail_idx & rxvq->qsz_mask];
-		  if (PREDICT_FALSE
-		      (rxvq->desc[desc_head].flags & VIRTQ_DESC_F_INDIRECT))
-		    {
-		      //It is seriously unlikely that a driver will put indirect descriptor
-		      //after non-indirect descriptor.
-		      if (PREDICT_FALSE
-			  (rxvq->desc[desc_head].len < sizeof (vring_desc_t)))
-			{
-			  error = VHOST_USER_TX_FUNC_ERROR_INDIRECT_OVERFLOW;
-			  goto done;
-			}
-		      if (PREDICT_FALSE
-			  (!(desc_table =
-			     map_guest_mem (vui,
-					    rxvq->desc[desc_index].addr,
-					    &map_hint))))
-			{
-			  error = VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL;
-			  goto done;
-			}
-		      desc_index = 0;
-		    }
-		  buffer_map_addr = desc_table[desc_index].addr;
-		  buffer_len = desc_table[desc_index].len;
-		}
-	      else
-		{
-		  error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOMRG;
-		  goto done;
-		}
-	    }
-
-	  {
-	    vhost_copy_t *cpy = &vum->cpus[thread_index].copy[copy_len];
-	    copy_len++;
-	    cpy->len = bytes_left;
-	    cpy->len = (cpy->len > buffer_len) ? buffer_len : cpy->len;
-	    cpy->dst = buffer_map_addr;
-	    cpy->src = (uword) vlib_buffer_get_current (current_b0) +
-	      current_b0->current_length - bytes_left;
-
-	    bytes_left -= cpy->len;
-	    buffer_len -= cpy->len;
-	    buffer_map_addr += cpy->len;
-	    desc_len += cpy->len;
-
-	    CLIB_PREFETCH (&rxvq->desc, CLIB_CACHE_LINE_BYTES, LOAD);
-	  }
-
-	  // Check if vlib buffer has more data. If not, get more or break.
-	  if (PREDICT_TRUE (!bytes_left))
-	    {
-	      if (PREDICT_FALSE
-		  (current_b0->flags & VLIB_BUFFER_NEXT_PRESENT))
-		{
-		  current_b0 = vlib_get_buffer (vm, current_b0->next_buffer);
-		  bytes_left = current_b0->current_length;
-		}
-	      else
-		{
-		  //End of packet
-		  break;
-		}
-	    }
-	}
-
-      //Move from available to used ring
-      rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].id = desc_head;
-      rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].len = desc_len;
-      vhost_user_log_dirty_ring (vui, rxvq,
-				 ring[rxvq->last_used_idx & rxvq->qsz_mask]);
-      rxvq->last_avail_idx++;
-      rxvq->last_used_idx++;
-
-      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
-	{
-	  vum->cpus[thread_index].current_trace->hdr =
-	    vum->cpus[thread_index].tx_headers[tx_headers_len - 1];
-	}
-
-      n_left--;			//At the end for error counting when 'goto done' is invoked
-
-      /*
-       * Do the copy periodically to prevent
-       * vum->cpus[thread_index].copy array overflow and corrupt memory
-       */
-      if (PREDICT_FALSE (copy_len >= VHOST_USER_TX_COPY_THRESHOLD))
-	{
-	  if (PREDICT_FALSE
-	      (vhost_user_tx_copy (vui, vum->cpus[thread_index].copy,
-				   copy_len, &map_hint)))
-	    {
-	      vlib_error_count (vm, node->node_index,
-				VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL, 1);
-	    }
-	  copy_len = 0;
-
-	  /* give buffers back to driver */
-	  CLIB_MEMORY_BARRIER ();
-	  rxvq->used->idx = rxvq->last_used_idx;
-	  vhost_user_log_dirty_ring (vui, rxvq, idx);
-	}
-      buffers++;
-    }
-
-done:
-  //Do the memory copies
-  if (PREDICT_FALSE
-      (vhost_user_tx_copy (vui, vum->cpus[thread_index].copy,
-			   copy_len, &map_hint)))
-    {
-      vlib_error_count (vm, node->node_index,
-			VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL, 1);
-    }
-
-  CLIB_MEMORY_BARRIER ();
-  rxvq->used->idx = rxvq->last_used_idx;
-  vhost_user_log_dirty_ring (vui, rxvq, idx);
-
-  /*
-   * When n_left is set, error is always set to something too.
-   * In case error is due to lack of remaining buffers, we go back up and
-   * retry.
-   * The idea is that it is better to waste some time on packets
-   * that have been processed already than dropping them and get
-   * more fresh packets with a good likelyhood that they will be dropped too.
-   * This technique also gives more time to VM driver to pick-up packets.
-   * In case the traffic flows from physical to virtual interfaces, this
-   * technique will end-up leveraging the physical NIC buffer in order to
-   * absorb the VM's CPU jitter.
-   */
-  if (n_left && (error == VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF) && retry)
-    {
-      retry--;
-      goto retry;
-    }
-
-  /* interrupt (call) handling */
-  if ((rxvq->callfd_idx != ~0) &&
-      !(rxvq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
-    {
-      rxvq->n_since_last_int += frame->n_vectors - n_left;
-
-      if (rxvq->n_since_last_int > vum->coalesce_frames)
-	vhost_user_send_call (vm, rxvq);
-    }
-
-  vhost_user_vring_unlock (vui, qid);
-
-done3:
-  if (PREDICT_FALSE (n_left && error != VHOST_USER_TX_FUNC_ERROR_NONE))
-    {
-      vlib_error_count (vm, node->node_index, error, n_left);
-      vlib_increment_simple_counter
-	(vnet_main.interface_main.sw_if_counters
-	 + VNET_INTERFACE_COUNTER_DROP,
-	 thread_index, vui->sw_if_index, n_left);
-    }
-
-  vlib_buffer_free (vm, vlib_frame_args (frame), frame->n_vectors);
-  return frame->n_vectors;
-}
-
-static uword
-vhost_user_send_interrupt_process (vlib_main_t * vm,
-				   vlib_node_runtime_t * rt, vlib_frame_t * f)
-{
-  vhost_user_intf_t *vui;
-  f64 timeout = 3153600000.0 /* 100 years */ ;
-  uword event_type, *event_data = 0;
-  vhost_user_main_t *vum = &vhost_user_main;
-  u16 *queue;
-  f64 now, poll_time_remaining;
-  f64 next_timeout;
-  u8 stop_timer = 0;
-
-  while (1)
-    {
-      poll_time_remaining =
-	vlib_process_wait_for_event_or_clock (vm, timeout);
-      event_type = vlib_process_get_events (vm, &event_data);
-      vec_reset_length (event_data);
-
-      /*
-       * Use the remaining timeout if it is less than coalesce time to avoid
-       * resetting the existing timer in the middle of expiration
-       */
-      timeout = poll_time_remaining;
-      if (vlib_process_suspend_time_is_zero (timeout) ||
-	  (timeout > vum->coalesce_time))
-	timeout = vum->coalesce_time;
-
-      now = vlib_time_now (vm);
-      switch (event_type)
-	{
-	case VHOST_USER_EVENT_STOP_TIMER:
-	  stop_timer = 1;
-	  break;
-
-	case VHOST_USER_EVENT_START_TIMER:
-	  stop_timer = 0;
-	  if (!vlib_process_suspend_time_is_zero (poll_time_remaining))
-	    break;
-	  /* fall through */
-
-	case ~0:
-	  /* *INDENT-OFF* */
-	  pool_foreach (vui, vum->vhost_user_interfaces, {
-	      next_timeout = timeout;
-	      vec_foreach (queue, vui->rx_queues)
-		{
-		  vhost_user_vring_t *rxvq =
-		    &vui->vrings[VHOST_VRING_IDX_RX (*queue)];
-		  vhost_user_vring_t *txvq =
-		    &vui->vrings[VHOST_VRING_IDX_TX (*queue)];
-
-		  if (txvq->n_since_last_int)
-		    {
-		      if (now >= txvq->int_deadline)
-			vhost_user_send_call (vm, txvq);
-		      else
-			next_timeout = txvq->int_deadline - now;
-		    }
-
-		  if (rxvq->n_since_last_int)
-		    {
-		      if (now >= rxvq->int_deadline)
-			vhost_user_send_call (vm, rxvq);
-		      else
-			next_timeout = rxvq->int_deadline - now;
-		    }
-
-		  if ((next_timeout < timeout) && (next_timeout > 0.0))
-		    timeout = next_timeout;
-		}
-	  });
-          /* *INDENT-ON* */
-	  break;
-
-	default:
-	  clib_warning ("BUG: unhandled event type %d", event_type);
-	  break;
-	}
-      /* No less than 1 millisecond */
-      if (timeout < 1e-3)
-	timeout = 1e-3;
-      if (stop_timer)
-	timeout = 3153600000.0;
-    }
-  return 0;
-}
-
-/* *INDENT-OFF* */
-VLIB_REGISTER_NODE (vhost_user_send_interrupt_node,static) = {
-    .function = vhost_user_send_interrupt_process,
-    .type = VLIB_NODE_TYPE_PROCESS,
-    .name = "vhost-user-send-interrupt-process",
-};
-/* *INDENT-ON* */
-
-static clib_error_t *
-vhost_user_interface_rx_mode_change (vnet_main_t * vnm, u32 hw_if_index,
-				     u32 qid, vnet_hw_interface_rx_mode mode)
-{
-  vlib_main_t *vm = vnm->vlib_main;
-  vnet_hw_interface_t *hif = vnet_get_hw_interface (vnm, hw_if_index);
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui =
-    pool_elt_at_index (vum->vhost_user_interfaces, hif->dev_instance);
-  vhost_user_vring_t *txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)];
-
-  if ((mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT) ||
-      (mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE))
-    {
-      if (txvq->kickfd_idx == ~0)
-	{
-	  // We cannot support interrupt mode if the driver opts out
-	  return clib_error_return (0, "Driver does not support interrupt");
-	}
-      if (txvq->mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
-	{
-	  vum->ifq_count++;
-	  // Start the timer if this is the first encounter on interrupt
-	  // interface/queue
-	  if ((vum->ifq_count == 1) &&
-	      (vum->coalesce_time > 0.0) && (vum->coalesce_frames > 0))
-	    vlib_process_signal_event (vm,
-				       vhost_user_send_interrupt_node.index,
-				       VHOST_USER_EVENT_START_TIMER, 0);
-	}
-    }
-  else if (mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
-    {
-      if (((txvq->mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT) ||
-	   (txvq->mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE)) &&
-	  vum->ifq_count)
-	{
-	  vum->ifq_count--;
-	  // Stop the timer if there is no more interrupt interface/queue
-	  if ((vum->ifq_count == 0) &&
-	      (vum->coalesce_time > 0.0) && (vum->coalesce_frames > 0))
-	    vlib_process_signal_event (vm,
-				       vhost_user_send_interrupt_node.index,
-				       VHOST_USER_EVENT_STOP_TIMER, 0);
-	}
-    }
-
-  txvq->mode = mode;
-  if (mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
-    txvq->used->flags = VRING_USED_F_NO_NOTIFY;
-  else if ((mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE) ||
-	   (mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT))
-    txvq->used->flags = 0;
-  else
-    {
-      clib_warning ("BUG: unhandled mode %d changed for if %d queue %d", mode,
-		    hw_if_index, qid);
-      return clib_error_return (0, "unsupported");
-    }
-
-  return 0;
-}
-
-static clib_error_t *
-vhost_user_interface_admin_up_down (vnet_main_t * vnm, u32 hw_if_index,
-				    u32 flags)
-{
-  vnet_hw_interface_t *hif = vnet_get_hw_interface (vnm, hw_if_index);
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui =
-    pool_elt_at_index (vum->vhost_user_interfaces, hif->dev_instance);
-  u32 hw_flags = 0;
-  vui->admin_up = (flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) != 0;
-  hw_flags = vui->admin_up ? VNET_HW_INTERFACE_FLAG_LINK_UP : 0;
-
-  vnet_hw_interface_set_flags (vnm, vui->hw_if_index, hw_flags);
-
-  return /* no error */ 0;
-}
-
-/* *INDENT-OFF* */
-VNET_DEVICE_CLASS (vhost_user_dev_class,static) = {
-  .name = "vhost-user",
-  .tx_function = vhost_user_tx,
-  .tx_function_n_errors = VHOST_USER_TX_FUNC_N_ERROR,
-  .tx_function_error_strings = vhost_user_tx_func_error_strings,
-  .format_device_name = format_vhost_user_interface_name,
-  .name_renumber = vhost_user_name_renumber,
-  .admin_up_down_function = vhost_user_interface_admin_up_down,
-  .rx_mode_change_function = vhost_user_interface_rx_mode_change,
-  .format_tx_trace = format_vhost_trace,
-};
-
-VLIB_DEVICE_TX_FUNCTION_MULTIARCH (vhost_user_dev_class,
-				   vhost_user_tx)
-/* *INDENT-ON* */
-
-static uword
-vhost_user_process (vlib_main_t * vm,
-		    vlib_node_runtime_t * rt, vlib_frame_t * f)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui;
-  struct sockaddr_un sun;
-  int sockfd;
-  clib_file_t template = { 0 };
-  f64 timeout = 3153600000.0 /* 100 years */ ;
-  uword *event_data = 0;
-
-  sockfd = -1;
-  sun.sun_family = AF_UNIX;
-  template.read_function = vhost_user_socket_read;
-  template.error_function = vhost_user_socket_error;
-
-  while (1)
-    {
-      vlib_process_wait_for_event_or_clock (vm, timeout);
-      vlib_process_get_events (vm, &event_data);
-      vec_reset_length (event_data);
-
-      timeout = 3.0;
-
-      /* *INDENT-OFF* */
-      pool_foreach (vui, vum->vhost_user_interfaces, {
-
-	  if (vui->unix_server_index == ~0) { //Nothing to do for server sockets
-	      if (vui->clib_file_index == ~0)
-		{
-		  if ((sockfd < 0) &&
-		      ((sockfd = socket (AF_UNIX, SOCK_STREAM, 0)) < 0))
-		    {
-		      /*
-		       * 1st time error or new error for this interface,
-		       * spit out the message and record the error
-		       */
-		      if (!vui->sock_errno || (vui->sock_errno != errno))
-			{
-			  clib_unix_warning
-			    ("Error: Could not open unix socket for %s",
-			     vui->sock_filename);
-			  vui->sock_errno = errno;
-			}
-		      continue;
-		    }
-
-		  /* try to connect */
-		  strncpy (sun.sun_path, (char *) vui->sock_filename,
-			   sizeof (sun.sun_path) - 1);
-
-		  /* Avoid hanging VPP if the other end does not accept */
-		  if (fcntl(sockfd, F_SETFL, O_NONBLOCK) < 0)
-                      clib_unix_warning ("fcntl");
-
-		  if (connect (sockfd, (struct sockaddr *) &sun,
-			       sizeof (struct sockaddr_un)) == 0)
-		    {
-		      /* Set the socket to blocking as it was before */
-                      if (fcntl(sockfd, F_SETFL, 0) < 0)
-                        clib_unix_warning ("fcntl2");
-
-		      vui->sock_errno = 0;
-		      template.file_descriptor = sockfd;
-		      template.private_data =
-			  vui - vhost_user_main.vhost_user_interfaces;
-		      vui->clib_file_index = clib_file_add (&file_main, &template);
-
-		      /* This sockfd is considered consumed */
-		      sockfd = -1;
-		    }
-		  else
-		    {
-		      vui->sock_errno = errno;
-		    }
-		}
-	      else
-		{
-		  /* check if socket is alive */
-		  int error = 0;
-		  socklen_t len = sizeof (error);
-		  int fd = UNIX_GET_FD(vui->clib_file_index);
-		  int retval =
-		      getsockopt (fd, SOL_SOCKET, SO_ERROR, &error, &len);
-
-		  if (retval)
-		    {
-		      DBG_SOCK ("getsockopt returned %d", retval);
-		      vhost_user_if_disconnect (vui);
-		    }
-		}
-	  }
-      });
-      /* *INDENT-ON* */
-    }
-  return 0;
-}
-
-/* *INDENT-OFF* */
-VLIB_REGISTER_NODE (vhost_user_process_node,static) = {
-    .function = vhost_user_process,
-    .type = VLIB_NODE_TYPE_PROCESS,
-    .name = "vhost-user-process",
-};
-/* *INDENT-ON* */
-
-/**
- * Disables and reset interface structure.
- * It can then be either init again, or removed from used interfaces.
- */
-static void
-vhost_user_term_if (vhost_user_intf_t * vui)
-{
-  int q;
-  vhost_user_main_t *vum = &vhost_user_main;
-
-  // disconnect interface sockets
-  vhost_user_if_disconnect (vui);
-  vhost_user_update_iface_state (vui);
-
-  for (q = 0; q < VHOST_VRING_MAX_N; q++)
-    {
-      clib_mem_free ((void *) vui->vring_locks[q]);
-    }
-
-  if (vui->unix_server_index != ~0)
-    {
-      //Close server socket
-      clib_file_t *uf = pool_elt_at_index (file_main.file_pool,
-					   vui->unix_server_index);
-      clib_file_del (&file_main, uf);
-      vui->unix_server_index = ~0;
-      unlink (vui->sock_filename);
-    }
-
-  mhash_unset (&vum->if_index_by_sock_name, vui->sock_filename,
-	       &vui->if_index);
-}
-
-int
-vhost_user_delete_if (vnet_main_t * vnm, vlib_main_t * vm, u32 sw_if_index)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui;
-  int rv = 0;
-  vnet_hw_interface_t *hwif;
-  u16 *queue;
-
-  if (!(hwif = vnet_get_sup_hw_interface (vnm, sw_if_index)) ||
-      hwif->dev_class_index != vhost_user_dev_class.index)
-    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
-
-  DBG_SOCK ("Deleting vhost-user interface %s (instance %d)",
-	    hwif->name, hwif->dev_instance);
-
-  vui = pool_elt_at_index (vum->vhost_user_interfaces, hwif->dev_instance);
-
-  vec_foreach (queue, vui->rx_queues)
-  {
-    vhost_user_vring_t *txvq;
-
-    txvq = &vui->vrings[VHOST_VRING_IDX_TX (*queue)];
-    if ((vum->ifq_count > 0) &&
-	((txvq->mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT) ||
-	 (txvq->mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE)))
-      {
-	vum->ifq_count--;
-	// Stop the timer if there is no more interrupt interface/queue
-	if ((vum->ifq_count == 0) &&
-	    (vum->coalesce_time > 0.0) && (vum->coalesce_frames > 0))
-	  {
-	    vlib_process_signal_event (vm,
-				       vhost_user_send_interrupt_node.index,
-				       VHOST_USER_EVENT_STOP_TIMER, 0);
-	    break;
-	  }
-      }
-  }
-
-  // Disable and reset interface
-  vhost_user_term_if (vui);
-
-  // Reset renumbered iface
-  if (hwif->dev_instance <
-      vec_len (vum->show_dev_instance_by_real_dev_instance))
-    vum->show_dev_instance_by_real_dev_instance[hwif->dev_instance] = ~0;
-
-  // Delete ethernet interface
-  ethernet_delete_interface (vnm, vui->hw_if_index);
-
-  // Back to pool
-  pool_put (vum->vhost_user_interfaces, vui);
-
-  return rv;
-}
-
-static clib_error_t *
-vhost_user_exit (vlib_main_t * vm)
-{
-  vnet_main_t *vnm = vnet_get_main ();
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui;
-
-  vlib_worker_thread_barrier_sync (vlib_get_main ());
-  /* *INDENT-OFF* */
-  pool_foreach (vui, vum->vhost_user_interfaces, {
-      vhost_user_delete_if (vnm, vm, vui->sw_if_index);
-  });
-  /* *INDENT-ON* */
-  vlib_worker_thread_barrier_release (vlib_get_main ());
-  return 0;
-}
-
-VLIB_MAIN_LOOP_EXIT_FUNCTION (vhost_user_exit);
-
-/**
- * Open server unix socket on specified sock_filename.
- */
-static int
-vhost_user_init_server_sock (const char *sock_filename, int *sock_fd)
-{
-  int rv = 0;
-  struct sockaddr_un un = { };
-  int fd;
-  /* create listening socket */
-  if ((fd = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
-    return VNET_API_ERROR_SYSCALL_ERROR_1;
-
-  un.sun_family = AF_UNIX;
-  strncpy ((char *) un.sun_path, (char *) sock_filename,
-	   sizeof (un.sun_path) - 1);
-
-  /* remove if exists */
-  unlink ((char *) sock_filename);
-
-  if (bind (fd, (struct sockaddr *) &un, sizeof (un)) == -1)
-    {
-      rv = VNET_API_ERROR_SYSCALL_ERROR_2;
-      goto error;
-    }
-
-  if (listen (fd, 1) == -1)
-    {
-      rv = VNET_API_ERROR_SYSCALL_ERROR_3;
-      goto error;
-    }
-
-  *sock_fd = fd;
-  return 0;
-
-error:
-  close (fd);
-  return rv;
-}
-
-/**
- * Create ethernet interface for vhost user interface.
- */
-static void
-vhost_user_create_ethernet (vnet_main_t * vnm, vlib_main_t * vm,
-			    vhost_user_intf_t * vui, u8 * hwaddress)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  u8 hwaddr[6];
-  clib_error_t *error;
-
-  /* create hw and sw interface */
-  if (hwaddress)
-    {
-      clib_memcpy (hwaddr, hwaddress, 6);
-    }
-  else
-    {
-      random_u32 (&vum->random);
-      clib_memcpy (hwaddr + 2, &vum->random, sizeof (vum->random));
-      hwaddr[0] = 2;
-      hwaddr[1] = 0xfe;
-    }
-
-  error = ethernet_register_interface
-    (vnm,
-     vhost_user_dev_class.index,
-     vui - vum->vhost_user_interfaces /* device instance */ ,
-     hwaddr /* ethernet address */ ,
-     &vui->hw_if_index, 0 /* flag change */ );
-
-  if (error)
-    clib_error_report (error);
-
-  vnet_sw_interface_set_mtu (vnm, vui->sw_if_index, 9000);
-}
-
-/*
- *  Initialize vui with specified attributes
- */
-static void
-vhost_user_vui_init (vnet_main_t * vnm,
-		     vhost_user_intf_t * vui,
-		     int server_sock_fd,
-		     const char *sock_filename,
-		     u64 feature_mask, u32 * sw_if_index)
-{
-  vnet_sw_interface_t *sw;
-  int q;
-  vhost_user_main_t *vum = &vhost_user_main;
-  vnet_hw_interface_t *hw;
-
-  hw = vnet_get_hw_interface (vnm, vui->hw_if_index);
-  sw = vnet_get_hw_sw_interface (vnm, vui->hw_if_index);
-  if (server_sock_fd != -1)
-    {
-      clib_file_t template = { 0 };
-      template.read_function = vhost_user_socksvr_accept_ready;
-      template.file_descriptor = server_sock_fd;
-      template.private_data = vui - vum->vhost_user_interfaces;	//hw index
-      vui->unix_server_index = clib_file_add (&file_main, &template);
-    }
-  else
-    {
-      vui->unix_server_index = ~0;
-    }
-
-  vui->sw_if_index = sw->sw_if_index;
-  strncpy (vui->sock_filename, sock_filename,
-	   ARRAY_LEN (vui->sock_filename) - 1);
-  vui->sock_errno = 0;
-  vui->is_up = 0;
-  vui->feature_mask = feature_mask;
-  vui->clib_file_index = ~0;
-  vui->log_base_addr = 0;
-  vui->if_index = vui - vum->vhost_user_interfaces;
-  mhash_set_mem (&vum->if_index_by_sock_name, vui->sock_filename,
-		 &vui->if_index, 0);
-
-  for (q = 0; q < VHOST_VRING_MAX_N; q++)
-    vhost_user_vring_init (vui, q);
-
-  hw->flags |= VNET_HW_INTERFACE_FLAG_SUPPORTS_INT_MODE;
-  vnet_hw_interface_set_flags (vnm, vui->hw_if_index, 0);
-
-  if (sw_if_index)
-    *sw_if_index = vui->sw_if_index;
-
-  for (q = 0; q < VHOST_VRING_MAX_N; q++)
-    {
-      vui->vring_locks[q] = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES,
-						    CLIB_CACHE_LINE_BYTES);
-      memset ((void *) vui->vring_locks[q], 0, CLIB_CACHE_LINE_BYTES);
-    }
-
-  vec_validate (vui->per_cpu_tx_qid,
-		vlib_get_thread_main ()->n_vlib_mains - 1);
-  vhost_user_tx_thread_placement (vui);
-}
-
-int
-vhost_user_create_if (vnet_main_t * vnm, vlib_main_t * vm,
-		      const char *sock_filename,
-		      u8 is_server,
-		      u32 * sw_if_index,
-		      u64 feature_mask,
-		      u8 renumber, u32 custom_dev_instance, u8 * hwaddr)
-{
-  vhost_user_intf_t *vui = NULL;
-  u32 sw_if_idx = ~0;
-  int rv = 0;
-  int server_sock_fd = -1;
-  vhost_user_main_t *vum = &vhost_user_main;
-  uword *if_index;
-
-  if (sock_filename == NULL || !(strlen (sock_filename) > 0))
-    {
-      return VNET_API_ERROR_INVALID_ARGUMENT;
-    }
-
-  if_index = mhash_get (&vum->if_index_by_sock_name, (void *) sock_filename);
-  if (if_index)
-    {
-      if (sw_if_index)
-	{
-	  vui = &vum->vhost_user_interfaces[*if_index];
-	  *sw_if_index = vui->sw_if_index;
-	}
-      return VNET_API_ERROR_IF_ALREADY_EXISTS;
-    }
-
-  if (is_server)
-    {
-      if ((rv =
-	   vhost_user_init_server_sock (sock_filename, &server_sock_fd)) != 0)
-	{
-	  return rv;
-	}
-    }
-
-  pool_get (vhost_user_main.vhost_user_interfaces, vui);
-
-  vhost_user_create_ethernet (vnm, vm, vui, hwaddr);
-  vhost_user_vui_init (vnm, vui, server_sock_fd, sock_filename,
-		       feature_mask, &sw_if_idx);
-
-  if (renumber)
-    vnet_interface_name_renumber (sw_if_idx, custom_dev_instance);
-
-  if (sw_if_index)
-    *sw_if_index = sw_if_idx;
-
-  // Process node must connect
-  vlib_process_signal_event (vm, vhost_user_process_node.index, 0, 0);
-
-  return rv;
-}
-
-int
-vhost_user_modify_if (vnet_main_t * vnm, vlib_main_t * vm,
-		      const char *sock_filename,
-		      u8 is_server,
-		      u32 sw_if_index,
-		      u64 feature_mask, u8 renumber, u32 custom_dev_instance)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui = NULL;
-  u32 sw_if_idx = ~0;
-  int server_sock_fd = -1;
-  int rv = 0;
-  vnet_hw_interface_t *hwif;
-  uword *if_index;
-
-  if (!(hwif = vnet_get_sup_hw_interface (vnm, sw_if_index)) ||
-      hwif->dev_class_index != vhost_user_dev_class.index)
-    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
-
-  if (sock_filename == NULL || !(strlen (sock_filename) > 0))
-    return VNET_API_ERROR_INVALID_ARGUMENT;
-
-  vui = vec_elt_at_index (vum->vhost_user_interfaces, hwif->dev_instance);
-
-  /*
-   * Disallow changing the interface to have the same path name
-   * as other interface
-   */
-  if_index = mhash_get (&vum->if_index_by_sock_name, (void *) sock_filename);
-  if (if_index && (*if_index != vui->if_index))
-    return VNET_API_ERROR_IF_ALREADY_EXISTS;
-
-  // First try to open server socket
-  if (is_server)
-    if ((rv = vhost_user_init_server_sock (sock_filename,
-					   &server_sock_fd)) != 0)
-      return rv;
-
-  vhost_user_term_if (vui);
-  vhost_user_vui_init (vnm, vui, server_sock_fd,
-		       sock_filename, feature_mask, &sw_if_idx);
-
-  if (renumber)
-    vnet_interface_name_renumber (sw_if_idx, custom_dev_instance);
-
-  // Process node must connect
-  vlib_process_signal_event (vm, vhost_user_process_node.index, 0, 0);
-
-  return rv;
-}
-
-clib_error_t *
-vhost_user_connect_command_fn (vlib_main_t * vm,
-			       unformat_input_t * input,
-			       vlib_cli_command_t * cmd)
-{
-  unformat_input_t _line_input, *line_input = &_line_input;
-  u8 *sock_filename = NULL;
-  u32 sw_if_index;
-  u8 is_server = 0;
-  u64 feature_mask = (u64) ~ (0ULL);
-  u8 renumber = 0;
-  u32 custom_dev_instance = ~0;
-  u8 hwaddr[6];
-  u8 *hw = NULL;
-  clib_error_t *error = NULL;
-
-  /* Get a line of input. */
-  if (!unformat_user (input, unformat_line_input, line_input))
-    return 0;
-
-  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
-    {
-      if (unformat (line_input, "socket %s", &sock_filename))
-	;
-      else if (unformat (line_input, "server"))
-	is_server = 1;
-      else if (unformat (line_input, "feature-mask 0x%llx", &feature_mask))
-	;
-      else
-	if (unformat
-	    (line_input, "hwaddr %U", unformat_ethernet_address, hwaddr))
-	hw = hwaddr;
-      else if (unformat (line_input, "renumber %d", &custom_dev_instance))
-	{
-	  renumber = 1;
-	}
-      else
-	{
-	  error = clib_error_return (0, "unknown input `%U'",
-				     format_unformat_error, line_input);
-	  goto done;
-	}
-    }
-
-  vnet_main_t *vnm = vnet_get_main ();
-
-  int rv;
-  if ((rv = vhost_user_create_if (vnm, vm, (char *) sock_filename,
-				  is_server, &sw_if_index, feature_mask,
-				  renumber, custom_dev_instance, hw)))
-    {
-      error = clib_error_return (0, "vhost_user_create_if returned %d", rv);
-      goto done;
-    }
-
-  vlib_cli_output (vm, "%U\n", format_vnet_sw_if_index_name, vnet_get_main (),
-		   sw_if_index);
-
-done:
-  vec_free (sock_filename);
-  unformat_free (line_input);
-
-  return error;
-}
-
-clib_error_t *
-vhost_user_delete_command_fn (vlib_main_t * vm,
-			      unformat_input_t * input,
-			      vlib_cli_command_t * cmd)
-{
-  unformat_input_t _line_input, *line_input = &_line_input;
-  u32 sw_if_index = ~0;
-  vnet_main_t *vnm = vnet_get_main ();
-  clib_error_t *error = NULL;
-
-  /* Get a line of input. */
-  if (!unformat_user (input, unformat_line_input, line_input))
-    return 0;
-
-  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
-    {
-      if (unformat (line_input, "sw_if_index %d", &sw_if_index))
-	;
-      else if (unformat
-	       (line_input, "%U", unformat_vnet_sw_interface, vnm,
-		&sw_if_index))
-	{
-	  vnet_hw_interface_t *hwif =
-	    vnet_get_sup_hw_interface (vnm, sw_if_index);
-	  if (hwif == NULL ||
-	      vhost_user_dev_class.index != hwif->dev_class_index)
-	    {
-	      error = clib_error_return (0, "Not a vhost interface");
-	      goto done;
-	    }
-	}
-      else
-	{
-	  error = clib_error_return (0, "unknown input `%U'",
-				     format_unformat_error, line_input);
-	  goto done;
-	}
-    }
-
-  vhost_user_delete_if (vnm, vm, sw_if_index);
-
-done:
-  unformat_free (line_input);
-
-  return error;
-}
-
-int
-vhost_user_dump_ifs (vnet_main_t * vnm, vlib_main_t * vm,
-		     vhost_user_intf_details_t ** out_vuids)
-{
-  int rv = 0;
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui;
-  vhost_user_intf_details_t *r_vuids = NULL;
-  vhost_user_intf_details_t *vuid = NULL;
-  u32 *hw_if_indices = 0;
-  vnet_hw_interface_t *hi;
-  u8 *s = NULL;
-  int i;
-
-  if (!out_vuids)
-    return -1;
-
-  pool_foreach (vui, vum->vhost_user_interfaces,
-		vec_add1 (hw_if_indices, vui->hw_if_index);
-    );
-
-  for (i = 0; i < vec_len (hw_if_indices); i++)
-    {
-      hi = vnet_get_hw_interface (vnm, hw_if_indices[i]);
-      vui = pool_elt_at_index (vum->vhost_user_interfaces, hi->dev_instance);
-
-      vec_add2 (r_vuids, vuid, 1);
-      vuid->sw_if_index = vui->sw_if_index;
-      vuid->virtio_net_hdr_sz = vui->virtio_net_hdr_sz;
-      vuid->features = vui->features;
-      vuid->num_regions = vui->nregions;
-      vuid->is_server = vui->unix_server_index != ~0;
-      vuid->sock_errno = vui->sock_errno;
-      strncpy ((char *) vuid->sock_filename, (char *) vui->sock_filename,
-	       sizeof (vuid->sock_filename));
-      vuid->sock_filename[ARRAY_LEN (vuid->sock_filename) - 1] = '\0';
-      s = format (s, "%v%c", hi->name, 0);
-
-      strncpy ((char *) vuid->if_name, (char *) s,
-	       ARRAY_LEN (vuid->if_name) - 1);
-      _vec_len (s) = 0;
-    }
-
-  vec_free (s);
-  vec_free (hw_if_indices);
-
-  *out_vuids = r_vuids;
-
-  return rv;
-}
-
-clib_error_t *
-show_vhost_user_command_fn (vlib_main_t * vm,
-			    unformat_input_t * input,
-			    vlib_cli_command_t * cmd)
-{
-  clib_error_t *error = 0;
-  vnet_main_t *vnm = vnet_get_main ();
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui;
-  u32 hw_if_index, *hw_if_indices = 0;
-  vnet_hw_interface_t *hi;
-  u16 *queue;
-  u32 ci;
-  int i, j, q;
-  int show_descr = 0;
-  struct feat_struct
-  {
-    u8 bit;
-    char *str;
-  };
-  struct feat_struct *feat_entry;
-
-  static struct feat_struct feat_array[] = {
-#define _(s,b) { .str = #s, .bit = b, },
-    foreach_virtio_net_feature
-#undef _
-    {.str = NULL}
-  };
-
-#define foreach_protocol_feature \
-  _(VHOST_USER_PROTOCOL_F_MQ) \
-  _(VHOST_USER_PROTOCOL_F_LOG_SHMFD)
-
-  static struct feat_struct proto_feat_array[] = {
-#define _(s) { .str = #s, .bit = s},
-    foreach_protocol_feature
-#undef _
-    {.str = NULL}
-  };
-
-  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
-    {
-      if (unformat
-	  (input, "%U", unformat_vnet_hw_interface, vnm, &hw_if_index))
-	{
-	  hi = vnet_get_hw_interface (vnm, hw_if_index);
-	  if (vhost_user_dev_class.index != hi->dev_class_index)
-	    {
-	      error = clib_error_return (0, "unknown input `%U'",
-					 format_unformat_error, input);
-	      goto done;
-	    }
-	  vec_add1 (hw_if_indices, hw_if_index);
-	}
-      else if (unformat (input, "descriptors") || unformat (input, "desc"))
-	show_descr = 1;
-      else
-	{
-	  error = clib_error_return (0, "unknown input `%U'",
-				     format_unformat_error, input);
-	  goto done;
-	}
-    }
-  if (vec_len (hw_if_indices) == 0)
-    {
-      pool_foreach (vui, vum->vhost_user_interfaces,
-		    vec_add1 (hw_if_indices, vui->hw_if_index);
-	);
-    }
-  vlib_cli_output (vm, "Virtio vhost-user interfaces");
-  vlib_cli_output (vm, "Global:\n  coalesce frames %d time %e",
-		   vum->coalesce_frames, vum->coalesce_time);
-  vlib_cli_output (vm, "  number of rx virtqueues in interrupt mode: %d",
-		   vum->ifq_count);
-
-  for (i = 0; i < vec_len (hw_if_indices); i++)
-    {
-      hi = vnet_get_hw_interface (vnm, hw_if_indices[i]);
-      vui = pool_elt_at_index (vum->vhost_user_interfaces, hi->dev_instance);
-      vlib_cli_output (vm, "Interface: %s (ifindex %d)",
-		       hi->name, hw_if_indices[i]);
-
-      vlib_cli_output (vm, "virtio_net_hdr_sz %d\n"
-		       " features mask (0x%llx): \n"
-		       " features (0x%llx): \n",
-		       vui->virtio_net_hdr_sz, vui->feature_mask,
-		       vui->features);
-
-      feat_entry = (struct feat_struct *) &feat_array;
-      while (feat_entry->str)
-	{
-	  if (vui->features & (1ULL << feat_entry->bit))
-	    vlib_cli_output (vm, "   %s (%d)", feat_entry->str,
-			     feat_entry->bit);
-	  feat_entry++;
-	}
-
-      vlib_cli_output (vm, "  protocol features (0x%llx)",
-		       vui->protocol_features);
-      feat_entry = (struct feat_struct *) &proto_feat_array;
-      while (feat_entry->str)
-	{
-	  if (vui->protocol_features & (1ULL << feat_entry->bit))
-	    vlib_cli_output (vm, "   %s (%d)", feat_entry->str,
-			     feat_entry->bit);
-	  feat_entry++;
-	}
-
-      vlib_cli_output (vm, "\n");
-
-      vlib_cli_output (vm, " socket filename %s type %s errno \"%s\"\n\n",
-		       vui->sock_filename,
-		       (vui->unix_server_index != ~0) ? "server" : "client",
-		       strerror (vui->sock_errno));
-
-      vlib_cli_output (vm, " rx placement: ");
-
-      vec_foreach (queue, vui->rx_queues)
-      {
-	vnet_main_t *vnm = vnet_get_main ();
-	uword thread_index;
-	vnet_hw_interface_rx_mode mode;
-
-	thread_index = vnet_get_device_input_thread_index (vnm,
-							   vui->hw_if_index,
-							   *queue);
-	vnet_hw_interface_get_rx_mode (vnm, vui->hw_if_index, *queue, &mode);
-	vlib_cli_output (vm, "   thread %d on vring %d, %U\n",
-			 thread_index, VHOST_VRING_IDX_TX (*queue),
-			 format_vnet_hw_interface_rx_mode, mode);
-      }
-
-      vlib_cli_output (vm, " tx placement: %s\n",
-		       vui->use_tx_spinlock ? "spin-lock" : "lock-free");
-
-      vec_foreach_index (ci, vui->per_cpu_tx_qid)
-      {
-	vlib_cli_output (vm, "   thread %d on vring %d\n", ci,
-			 VHOST_VRING_IDX_RX (vui->per_cpu_tx_qid[ci]));
-      }
-
-      vlib_cli_output (vm, "\n");
-
-      vlib_cli_output (vm, " Memory regions (total %d)\n", vui->nregions);
-
-      if (vui->nregions)
-	{
-	  vlib_cli_output (vm,
-			   " region fd    guest_phys_addr    memory_size        userspace_addr     mmap_offset        mmap_addr\n");
-	  vlib_cli_output (vm,
-			   " ====== ===== ================== ================== ================== ================== ==================\n");
-	}
-      for (j = 0; j < vui->nregions; j++)
-	{
-	  vlib_cli_output (vm,
-			   "  %d     %-5d 0x%016lx 0x%016lx 0x%016lx 0x%016lx 0x%016lx\n",
-			   j, vui->region_mmap_fd[j],
-			   vui->regions[j].guest_phys_addr,
-			   vui->regions[j].memory_size,
-			   vui->regions[j].userspace_addr,
-			   vui->regions[j].mmap_offset,
-			   pointer_to_uword (vui->region_mmap_addr[j]));
-	}
-      for (q = 0; q < VHOST_VRING_MAX_N; q++)
-	{
-	  if (!vui->vrings[q].started)
-	    continue;
-
-	  vlib_cli_output (vm, "\n Virtqueue %d (%s%s)\n", q,
-			   (q & 1) ? "RX" : "TX",
-			   vui->vrings[q].enabled ? "" : " disabled");
-
-	  vlib_cli_output (vm,
-			   "  qsz %d last_avail_idx %d last_used_idx %d\n",
-			   vui->vrings[q].qsz_mask + 1,
-			   vui->vrings[q].last_avail_idx,
-			   vui->vrings[q].last_used_idx);
-
-	  if (vui->vrings[q].avail && vui->vrings[q].used)
-	    vlib_cli_output (vm,
-			     "  avail.flags %x avail.idx %d used.flags %x used.idx %d\n",
-			     vui->vrings[q].avail->flags,
-			     vui->vrings[q].avail->idx,
-			     vui->vrings[q].used->flags,
-			     vui->vrings[q].used->idx);
-
-	  int kickfd = UNIX_GET_FD (vui->vrings[q].kickfd_idx);
-	  int callfd = UNIX_GET_FD (vui->vrings[q].callfd_idx);
-	  vlib_cli_output (vm, "  kickfd %d callfd %d errfd %d\n",
-			   kickfd, callfd, vui->vrings[q].errfd);
-
-	  if (show_descr)
-	    {
-	      vlib_cli_output (vm, "\n  descriptor table:\n");
-	      vlib_cli_output (vm,
-			       "   id          addr         len  flags  next      user_addr\n");
-	      vlib_cli_output (vm,
-			       "  ===== ================== ===== ====== ===== ==================\n");
-	      for (j = 0; j < vui->vrings[q].qsz_mask + 1; j++)
-		{
-		  u32 mem_hint = 0;
-		  vlib_cli_output (vm,
-				   "  %-5d 0x%016lx %-5d 0x%04x %-5d 0x%016lx\n",
-				   j, vui->vrings[q].desc[j].addr,
-				   vui->vrings[q].desc[j].len,
-				   vui->vrings[q].desc[j].flags,
-				   vui->vrings[q].desc[j].next,
-				   pointer_to_uword (map_guest_mem
-						     (vui,
-						      vui->vrings[q].desc[j].
-						      addr, &mem_hint)));
-		}
-	    }
-	}
-      vlib_cli_output (vm, "\n");
-    }
-done:
-  vec_free (hw_if_indices);
-  return error;
-}
-
-/*
- * CLI functions
- */
-
-/*?
- * Create a vHost User interface. Once created, a new virtual interface
- * will exist with the name '<em>VirtualEthernet0/0/x</em>', where '<em>x</em>'
- * is the next free index.
- *
- * There are several parameters associated with a vHost interface:
- *
- * - <b>socket <socket-filename></b> - Name of the linux socket used by hypervisor
- * and VPP to manage the vHost interface. If in '<em>server</em>' mode, VPP will
- * create the socket if it does not already exist. If in '<em>client</em>' mode,
- * hypervisor will create the socket if it does not already exist. The VPP code
- * is indifferent to the file location. However, if SELinux is enabled, then the
- * socket needs to be created in '<em>/var/run/vpp/</em>'.
- *
- * - <b>server</b> - Optional flag to indicate that VPP should be the server for
- * the linux socket. If not provided, VPP will be the client. In '<em>server</em>'
- *  mode, the VM can be reset without tearing down the vHost Interface. In
- * '<em>client</em>' mode, VPP can be reset without bringing down the VM and
- * tearing down the vHost Interface.
- *
- * - <b>feature-mask <hex></b> - Optional virtio/vhost feature set negotiated at
- * startup. <b>This is intended for degugging only.</b> It is recommended that this
- * parameter not be used except by experienced users. By default, all supported
- * features will be advertised. Otherwise, provide the set of features desired.
- *   - 0x000008000 (15) - VIRTIO_NET_F_MRG_RXBUF
- *   - 0x000020000 (17) - VIRTIO_NET_F_CTRL_VQ
- *   - 0x000200000 (21) - VIRTIO_NET_F_GUEST_ANNOUNCE
- *   - 0x000400000 (22) - VIRTIO_NET_F_MQ
- *   - 0x004000000 (26) - VHOST_F_LOG_ALL
- *   - 0x008000000 (27) - VIRTIO_F_ANY_LAYOUT
- *   - 0x010000000 (28) - VIRTIO_F_INDIRECT_DESC
- *   - 0x040000000 (30) - VHOST_USER_F_PROTOCOL_FEATURES
- *   - 0x100000000 (32) - VIRTIO_F_VERSION_1
- *
- * - <b>hwaddr <mac-addr></b> - Optional ethernet address, can be in either
- * X:X:X:X:X:X unix or X.X.X cisco format.
- *
- * - <b>renumber <dev_instance></b> - Optional parameter which allows the instance
- * in the name to be specified. If instance already exists, name will be used
- * anyway and multiple instances will have the same name. Use with caution.
- *
- * @cliexpar
- * Example of how to create a vhost interface with VPP as the client and all features enabled:
- * @cliexstart{create vhost-user socket /var/run/vpp/vhost1.sock}
- * VirtualEthernet0/0/0
- * @cliexend
- * Example of how to create a vhost interface with VPP as the server and with just
- * multiple queues enabled:
- * @cliexstart{create vhost-user socket /var/run/vpp/vhost2.sock server feature-mask 0x40400000}
- * VirtualEthernet0/0/1
- * @cliexend
- * Once the vHost interface is created, enable the interface using:
- * @cliexcmd{set interface state VirtualEthernet0/0/0 up}
-?*/
-/* *INDENT-OFF* */
-VLIB_CLI_COMMAND (vhost_user_connect_command, static) = {
-    .path = "create vhost-user",
-    .short_help = "create vhost-user socket <socket-filename> [server] "
-    "[feature-mask <hex>] [hwaddr <mac-addr>] [renumber <dev_instance>] ",
-    .function = vhost_user_connect_command_fn,
-};
-/* *INDENT-ON* */
-
-/*?
- * Delete a vHost User interface using the interface name or the
- * software interface index. Use the '<em>show interface</em>'
- * command to determine the software interface index. On deletion,
- * the linux socket will not be deleted.
- *
- * @cliexpar
- * Example of how to delete a vhost interface by name:
- * @cliexcmd{delete vhost-user VirtualEthernet0/0/1}
- * Example of how to delete a vhost interface by software interface index:
- * @cliexcmd{delete vhost-user sw_if_index 1}
-?*/
-/* *INDENT-OFF* */
-VLIB_CLI_COMMAND (vhost_user_delete_command, static) = {
-    .path = "delete vhost-user",
-    .short_help = "delete vhost-user {<interface> | sw_if_index <sw_idx>}",
-    .function = vhost_user_delete_command_fn,
-};
-
-/*?
- * Display the attributes of a single vHost User interface (provide interface
- * name), multiple vHost User interfaces (provide a list of interface names seperated
- * by spaces) or all Vhost User interfaces (omit an interface name to display all
- * vHost interfaces).
- *
- * @cliexpar
- * @parblock
- * Example of how to display a vhost interface:
- * @cliexstart{show vhost-user VirtualEthernet0/0/0}
- * Virtio vhost-user interfaces
- * Global:
- *   coalesce frames 32 time 1e-3
- * Interface: VirtualEthernet0/0/0 (ifindex 1)
- * virtio_net_hdr_sz 12
- *  features mask (0xffffffffffffffff):
- *  features (0x50408000):
- *    VIRTIO_NET_F_MRG_RXBUF (15)
- *    VIRTIO_NET_F_MQ (22)
- *    VIRTIO_F_INDIRECT_DESC (28)
- *    VHOST_USER_F_PROTOCOL_FEATURES (30)
- *   protocol features (0x3)
- *    VHOST_USER_PROTOCOL_F_MQ (0)
- *    VHOST_USER_PROTOCOL_F_LOG_SHMFD (1)
- *
- *  socket filename /var/run/vpp/vhost1.sock type client errno "Success"
- *
- * rx placement:
- *    thread 1 on vring 1
- *    thread 1 on vring 5
- *    thread 2 on vring 3
- *    thread 2 on vring 7
- *  tx placement: spin-lock
- *    thread 0 on vring 0
- *    thread 1 on vring 2
- *    thread 2 on vring 0
- *
- * Memory regions (total 2)
- * region fd    guest_phys_addr    memory_size        userspace_addr     mmap_offset        mmap_addr
- * ====== ===== ================== ================== ================== ================== ==================
- *   0     60    0x0000000000000000 0x00000000000a0000 0x00002aaaaac00000 0x0000000000000000 0x00002aab2b400000
- *   1     61    0x00000000000c0000 0x000000003ff40000 0x00002aaaaacc0000 0x00000000000c0000 0x00002aababcc0000
- *
- *  Virtqueue 0 (TX)
- *   qsz 256 last_avail_idx 0 last_used_idx 0
- *   avail.flags 1 avail.idx 128 used.flags 1 used.idx 0
- *   kickfd 62 callfd 64 errfd -1
- *
- *  Virtqueue 1 (RX)
- *   qsz 256 last_avail_idx 0 last_used_idx 0
- *   avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
- *   kickfd 65 callfd 66 errfd -1
- *
- *  Virtqueue 2 (TX)
- *   qsz 256 last_avail_idx 0 last_used_idx 0
- *   avail.flags 1 avail.idx 128 used.flags 1 used.idx 0
- *   kickfd 63 callfd 70 errfd -1
- *
- *  Virtqueue 3 (RX)
- *   qsz 256 last_avail_idx 0 last_used_idx 0
- *   avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
- *   kickfd 72 callfd 74 errfd -1
- *
- *  Virtqueue 4 (TX disabled)
- *   qsz 256 last_avail_idx 0 last_used_idx 0
- *   avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
- *   kickfd 76 callfd 78 errfd -1
- *
- *  Virtqueue 5 (RX disabled)
- *   qsz 256 last_avail_idx 0 last_used_idx 0
- *   avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
- *   kickfd 80 callfd 82 errfd -1
- *
- *  Virtqueue 6 (TX disabled)
- *   qsz 256 last_avail_idx 0 last_used_idx 0
- *  avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
- *   kickfd 84 callfd 86 errfd -1
- *
- *  Virtqueue 7 (RX disabled)
- *   qsz 256 last_avail_idx 0 last_used_idx 0
- *   avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
- *   kickfd 88 callfd 90 errfd -1
- *
- * @cliexend
- *
- * The optional '<em>descriptors</em>' parameter will display the same output as
- * the previous example but will include the descriptor table for each queue.
- * The output is truncated below:
- * @cliexstart{show vhost-user VirtualEthernet0/0/0 descriptors}
- * Virtio vhost-user interfaces
- * Global:
- *   coalesce frames 32 time 1e-3
- * Interface: VirtualEthernet0/0/0 (ifindex 1)
- * virtio_net_hdr_sz 12
- *  features mask (0xffffffffffffffff):
- *  features (0x50408000):
- *    VIRTIO_NET_F_MRG_RXBUF (15)
- *    VIRTIO_NET_F_MQ (22)
- * :
- *  Virtqueue 0 (TX)
- *   qsz 256 last_avail_idx 0 last_used_idx 0
- *   avail.flags 1 avail.idx 128 used.flags 1 used.idx 0
- *   kickfd 62 callfd 64 errfd -1
- *
- *   descriptor table:
- *    id          addr         len  flags  next      user_addr
- *   ===== ================== ===== ====== ===== ==================
- *   0     0x0000000010b6e974 2060  0x0002 1     0x00002aabbc76e974
- *   1     0x0000000010b6e034 2060  0x0002 2     0x00002aabbc76e034
- *   2     0x0000000010b6d6f4 2060  0x0002 3     0x00002aabbc76d6f4
- *   3     0x0000000010b6cdb4 2060  0x0002 4     0x00002aabbc76cdb4
- *   4     0x0000000010b6c474 2060  0x0002 5     0x00002aabbc76c474
- *   5     0x0000000010b6bb34 2060  0x0002 6     0x00002aabbc76bb34
- *   6     0x0000000010b6b1f4 2060  0x0002 7     0x00002aabbc76b1f4
- *   7     0x0000000010b6a8b4 2060  0x0002 8     0x00002aabbc76a8b4
- *   8     0x0000000010b69f74 2060  0x0002 9     0x00002aabbc769f74
- *   9     0x0000000010b69634 2060  0x0002 10    0x00002aabbc769634
- *   10    0x0000000010b68cf4 2060  0x0002 11    0x00002aabbc768cf4
- * :
- *   249   0x0000000000000000 0     0x0000 250   0x00002aab2b400000
- *   250   0x0000000000000000 0     0x0000 251   0x00002aab2b400000
- *   251   0x0000000000000000 0     0x0000 252   0x00002aab2b400000
- *   252   0x0000000000000000 0     0x0000 253   0x00002aab2b400000
- *   253   0x0000000000000000 0     0x0000 254   0x00002aab2b400000
- *   254   0x0000000000000000 0     0x0000 255   0x00002aab2b400000
- *   255   0x0000000000000000 0     0x0000 32768 0x00002aab2b400000
- *
- *  Virtqueue 1 (RX)
- *   qsz 256 last_avail_idx 0 last_used_idx 0
- * :
- * @cliexend
- * @endparblock
-?*/
-/* *INDENT-OFF* */
-VLIB_CLI_COMMAND (show_vhost_user_command, static) = {
-    .path = "show vhost-user",
-    .short_help = "show vhost-user [<interface> [<interface> [..]]] [descriptors]",
-    .function = show_vhost_user_command_fn,
-};
-/* *INDENT-ON* */
-
-clib_error_t *
-debug_vhost_user_command_fn (vlib_main_t * vm,
-			     unformat_input_t * input,
-			     vlib_cli_command_t * cmd)
-{
-  unformat_input_t _line_input, *line_input = &_line_input;
-  clib_error_t *error = NULL;
-  vhost_user_main_t *vum = &vhost_user_main;
-  u8 onoff = 0;
-  u8 input_found = 0;
-
-  /* Get a line of input. */
-  if (!unformat_user (input, unformat_line_input, line_input))
-    return clib_error_return (0, "missing argument");
-
-  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
-    {
-      if (input_found)
-	{
-	  error = clib_error_return (0, "unknown input `%U'",
-				     format_unformat_error, line_input);
-	  goto done;
-	}
-
-      if (unformat (line_input, "on"))
-	{
-	  input_found = 1;
-	  onoff = 1;
-	}
-      else if (unformat (line_input, "off"))
-	{
-	  input_found = 1;
-	  onoff = 0;
-	}
-      else
-	{
-	  error = clib_error_return (0, "unknown input `%U'",
-				     format_unformat_error, line_input);
-	  goto done;
-	}
-    }
-
-  vum->debug = onoff;
-
-done:
-  unformat_free (line_input);
-
-  return error;
-}
-
-/* *INDENT-OFF* */
-VLIB_CLI_COMMAND (debug_vhost_user_command, static) = {
-    .path = "debug vhost-user",
-    .short_help = "debug vhost-user <on | off>",
-    .function = debug_vhost_user_command_fn,
-};
-/* *INDENT-ON* */
-
-static clib_error_t *
-vhost_user_config (vlib_main_t * vm, unformat_input_t * input)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-
-  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
-    {
-      if (unformat (input, "coalesce-frames %d", &vum->coalesce_frames))
-	;
-      else if (unformat (input, "coalesce-time %f", &vum->coalesce_time))
-	;
-      else if (unformat (input, "dont-dump-memory"))
-	vum->dont_dump_vhost_user_memory = 1;
-      else
-	return clib_error_return (0, "unknown input `%U'",
-				  format_unformat_error, input);
-    }
-
-  return 0;
-}
-
-/* vhost-user { ... } configuration. */
-VLIB_CONFIG_FUNCTION (vhost_user_config, "vhost-user");
-
-void
-vhost_user_unmap_all (void)
-{
-  vhost_user_main_t *vum = &vhost_user_main;
-  vhost_user_intf_t *vui;
-
-  if (vum->dont_dump_vhost_user_memory)
-    {
-      pool_foreach (vui, vum->vhost_user_interfaces,
-		    unmap_all_mem_regions (vui);
-	);
-    }
-}
-
-/*
- * fd.io coding-style-patch-verification: ON
- *
- * Local Variables:
- * eval: (c-set-style "gnu")
- * End:
- */
diff --git a/src/vnet/devices/virtio/vhost_user.c b/src/vnet/devices/virtio/vhost_user.c
new file mode 100644
index 0000000..a8a7ae8
--- /dev/null
+++ b/src/vnet/devices/virtio/vhost_user.c
@@ -0,0 +1,2242 @@
+/*
+ *------------------------------------------------------------------
+ * vhost.c - vhost-user
+ *
+ * Copyright (c) 2014-2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+#include <fcntl.h>		/* for open */
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/uio.h>		/* for iovec */
+#include <netinet/in.h>
+#include <sys/vfs.h>
+
+#include <linux/if_arp.h>
+#include <linux/if_tun.h>
+
+#include <vlib/vlib.h>
+#include <vlib/unix/unix.h>
+
+#include <vnet/ip/ip.h>
+
+#include <vnet/ethernet/ethernet.h>
+#include <vnet/devices/devices.h>
+#include <vnet/feature/feature.h>
+
+#include <vnet/devices/virtio/vhost_user.h>
+#include <vnet/devices/virtio/vhost_user_inline.h>
+
+/**
+ * @file
+ * @brief vHost User Device Driver.
+ *
+ * This file contains the source code for vHost User interface.
+ */
+
+
+vlib_node_registration_t vhost_user_send_interrupt_node;
+
+/* *INDENT-OFF* */
+vhost_user_main_t vhost_user_main = {
+  .mtu_bytes = 1518,
+};
+
+VNET_HW_INTERFACE_CLASS (vhost_interface_class, static) = {
+  .name = "vhost-user",
+};
+/* *INDENT-ON* */
+
+static long
+get_huge_page_size (int fd)
+{
+  struct statfs s;
+  fstatfs (fd, &s);
+  return s.f_bsize;
+}
+
+static void
+unmap_all_mem_regions (vhost_user_intf_t * vui)
+{
+  int i, r;
+  for (i = 0; i < vui->nregions; i++)
+    {
+      if (vui->region_mmap_addr[i] != MAP_FAILED)
+	{
+
+	  long page_sz = get_huge_page_size (vui->region_mmap_fd[i]);
+
+	  ssize_t map_sz = (vui->regions[i].memory_size +
+			    vui->regions[i].mmap_offset +
+			    page_sz - 1) & ~(page_sz - 1);
+
+	  r =
+	    munmap (vui->region_mmap_addr[i] - vui->regions[i].mmap_offset,
+		    map_sz);
+
+	  DBG_SOCK
+	    ("unmap memory region %d addr 0x%lx len 0x%lx page_sz 0x%x", i,
+	     vui->region_mmap_addr[i], map_sz, page_sz);
+
+	  vui->region_mmap_addr[i] = MAP_FAILED;
+
+	  if (r == -1)
+	    {
+	      clib_warning ("failed to unmap memory region (errno %d)",
+			    errno);
+	    }
+	  close (vui->region_mmap_fd[i]);
+	}
+    }
+  vui->nregions = 0;
+}
+
+static void
+vhost_user_tx_thread_placement (vhost_user_intf_t * vui)
+{
+  //Let's try to assign one queue to each thread
+  u32 qid = 0;
+  u32 thread_index = 0;
+  vui->use_tx_spinlock = 0;
+  while (1)
+    {
+      for (qid = 0; qid < VHOST_VRING_MAX_N / 2; qid++)
+	{
+	  vhost_user_vring_t *rxvq = &vui->vrings[VHOST_VRING_IDX_RX (qid)];
+	  if (!rxvq->started || !rxvq->enabled)
+	    continue;
+
+	  vui->per_cpu_tx_qid[thread_index] = qid;
+	  thread_index++;
+	  if (thread_index == vlib_get_thread_main ()->n_vlib_mains)
+	    return;
+	}
+      //We need to loop, meaning the spinlock has to be used
+      vui->use_tx_spinlock = 1;
+      if (thread_index == 0)
+	{
+	  //Could not find a single valid one
+	  for (thread_index = 0;
+	       thread_index < vlib_get_thread_main ()->n_vlib_mains;
+	       thread_index++)
+	    {
+	      vui->per_cpu_tx_qid[thread_index] = 0;
+	    }
+	  return;
+	}
+    }
+}
+
+/**
+ * @brief Unassign existing interface/queue to thread mappings and re-assign
+ * new interface/queue to thread mappings
+ */
+static void
+vhost_user_rx_thread_placement ()
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui;
+  vhost_user_vring_t *txvq;
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 qid;
+  int rv;
+  u16 *queue;
+
+  // Scrap all existing mappings for all interfaces/queues
+  /* *INDENT-OFF* */
+  pool_foreach (vui, vum->vhost_user_interfaces, {
+      vec_foreach (queue, vui->rx_queues)
+	{
+	  rv = vnet_hw_interface_unassign_rx_thread (vnm, vui->hw_if_index,
+						     *queue);
+	  if (rv)
+	    clib_warning ("Warning: unable to unassign interface %d, "
+			  "queue %d: rc=%d", vui->hw_if_index, *queue, rv);
+	}
+      vec_reset_length (vui->rx_queues);
+  });
+  /* *INDENT-ON* */
+
+  // Create the rx_queues for all interfaces
+  /* *INDENT-OFF* */
+  pool_foreach (vui, vum->vhost_user_interfaces, {
+      for (qid = 0; qid < VHOST_VRING_MAX_N / 2; qid++)
+	{
+	  txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)];
+	  if (txvq->started)
+	    {
+	      if (txvq->mode == VNET_HW_INTERFACE_RX_MODE_UNKNOWN)
+		/* Set polling as the default */
+		txvq->mode = VNET_HW_INTERFACE_RX_MODE_POLLING;
+	      vec_add1 (vui->rx_queues, qid);
+	    }
+	}
+  });
+  /* *INDENT-ON* */
+
+  // Assign new mappings for all interfaces/queues
+  /* *INDENT-OFF* */
+  pool_foreach (vui, vum->vhost_user_interfaces, {
+      vnet_hw_interface_set_input_node (vnm, vui->hw_if_index,
+					vhost_user_input_node.index);
+      vec_foreach (queue, vui->rx_queues)
+	{
+	  vnet_hw_interface_assign_rx_thread (vnm, vui->hw_if_index, *queue,
+					      ~0);
+	  txvq = &vui->vrings[VHOST_VRING_IDX_TX (*queue)];
+	  rv = vnet_hw_interface_set_rx_mode (vnm, vui->hw_if_index, *queue,
+					      txvq->mode);
+	  if (rv)
+	    clib_warning ("Warning: unable to set rx mode for interface %d, "
+			  "queue %d: rc=%d", vui->hw_if_index, *queue, rv);
+	}
+  });
+  /* *INDENT-ON* */
+}
+
+/** @brief Returns whether at least one TX and one RX vring are enabled */
+static_always_inline int
+vhost_user_intf_ready (vhost_user_intf_t * vui)
+{
+  int i, found[2] = { };	//RX + TX
+
+  for (i = 0; i < VHOST_VRING_MAX_N; i++)
+    if (vui->vrings[i].started && vui->vrings[i].enabled)
+      found[i & 1] = 1;
+
+  return found[0] && found[1];
+}
+
+static void
+vhost_user_update_iface_state (vhost_user_intf_t * vui)
+{
+  /* if we have pointers to descriptor table, go up */
+  int is_up = vhost_user_intf_ready (vui);
+  if (is_up != vui->is_up)
+    {
+      DBG_SOCK ("interface %d %s", vui->sw_if_index,
+		is_up ? "ready" : "down");
+      vnet_hw_interface_set_flags (vnet_get_main (), vui->hw_if_index,
+				   is_up ? VNET_HW_INTERFACE_FLAG_LINK_UP :
+				   0);
+      vui->is_up = is_up;
+    }
+  vhost_user_rx_thread_placement ();
+  vhost_user_tx_thread_placement (vui);
+}
+
+static void
+vhost_user_set_interrupt_pending (vhost_user_intf_t * vui, u32 ifq)
+{
+  u32 qid;
+  vnet_main_t *vnm = vnet_get_main ();
+
+  qid = ifq & 0xff;
+  if ((qid & 1) == 0)
+    /* Only care about the odd number, or TX, virtqueue */
+    return;
+
+  if (vhost_user_intf_ready (vui))
+    // qid >> 1 is to convert virtqueue number to vring queue index
+    vnet_device_input_set_interrupt_pending (vnm, vui->hw_if_index, qid >> 1);
+}
+
+static clib_error_t *
+vhost_user_callfd_read_ready (clib_file_t * uf)
+{
+  __attribute__ ((unused)) int n;
+  u8 buff[8];
+
+  n = read (uf->file_descriptor, ((char *) &buff), 8);
+
+  return 0;
+}
+
+static clib_error_t *
+vhost_user_kickfd_read_ready (clib_file_t * uf)
+{
+  __attribute__ ((unused)) int n;
+  u8 buff[8];
+  vhost_user_intf_t *vui =
+    pool_elt_at_index (vhost_user_main.vhost_user_interfaces,
+		       uf->private_data >> 8);
+  u32 qid = uf->private_data & 0xff;
+
+  n = read (uf->file_descriptor, ((char *) &buff), 8);
+  DBG_SOCK ("if %d KICK queue %d", uf->private_data >> 8, qid);
+  if (!vui->vrings[qid].started ||
+      (vhost_user_intf_ready (vui) != vui->is_up))
+    {
+      vlib_worker_thread_barrier_sync (vlib_get_main ());
+      vui->vrings[qid].started = 1;
+      vhost_user_update_iface_state (vui);
+      vlib_worker_thread_barrier_release (vlib_get_main ());
+    }
+
+  vhost_user_set_interrupt_pending (vui, uf->private_data);
+  return 0;
+}
+
+static_always_inline void
+vhost_user_vring_init (vhost_user_intf_t * vui, u32 qid)
+{
+  vhost_user_vring_t *vring = &vui->vrings[qid];
+  memset (vring, 0, sizeof (*vring));
+  vring->kickfd_idx = ~0;
+  vring->callfd_idx = ~0;
+  vring->errfd = -1;
+
+  /*
+   * We have a bug with some qemu 2.5, and this may be a fix.
+   * Feel like interpretation holy text, but this is from vhost-user.txt.
+   * "
+   * One queue pair is enabled initially. More queues are enabled
+   * dynamically, by sending message VHOST_USER_SET_VRING_ENABLE.
+   * "
+   * Don't know who's right, but this is what DPDK does.
+   */
+  if (qid == 0 || qid == 1)
+    vring->enabled = 1;
+}
+
+static_always_inline void
+vhost_user_vring_close (vhost_user_intf_t * vui, u32 qid)
+{
+  vhost_user_vring_t *vring = &vui->vrings[qid];
+  if (vring->kickfd_idx != ~0)
+    {
+      clib_file_t *uf = pool_elt_at_index (file_main.file_pool,
+					   vring->kickfd_idx);
+      clib_file_del (&file_main, uf);
+      vring->kickfd_idx = ~0;
+    }
+  if (vring->callfd_idx != ~0)
+    {
+      clib_file_t *uf = pool_elt_at_index (file_main.file_pool,
+					   vring->callfd_idx);
+      clib_file_del (&file_main, uf);
+      vring->callfd_idx = ~0;
+    }
+  if (vring->errfd != -1)
+    {
+      close (vring->errfd);
+      vring->errfd = -1;
+    }
+  vhost_user_vring_init (vui, qid);
+}
+
+static_always_inline void
+vhost_user_if_disconnect (vhost_user_intf_t * vui)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  int q;
+
+  vnet_hw_interface_set_flags (vnm, vui->hw_if_index, 0);
+
+  if (vui->clib_file_index != ~0)
+    {
+      clib_file_del (&file_main, file_main.file_pool + vui->clib_file_index);
+      vui->clib_file_index = ~0;
+    }
+
+  vui->is_up = 0;
+
+  for (q = 0; q < VHOST_VRING_MAX_N; q++)
+    vhost_user_vring_close (vui, q);
+
+  unmap_all_mem_regions (vui);
+  DBG_SOCK ("interface ifindex %d disconnected", vui->sw_if_index);
+}
+
+static clib_error_t *
+vhost_user_socket_read (clib_file_t * uf)
+{
+  int n, i;
+  int fd, number_of_fds = 0;
+  int fds[VHOST_MEMORY_MAX_NREGIONS];
+  vhost_user_msg_t msg;
+  struct msghdr mh;
+  struct iovec iov[1];
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui;
+  struct cmsghdr *cmsg;
+  u8 q;
+  clib_file_t template = { 0 };
+  vnet_main_t *vnm = vnet_get_main ();
+
+  vui = pool_elt_at_index (vum->vhost_user_interfaces, uf->private_data);
+
+  char control[CMSG_SPACE (VHOST_MEMORY_MAX_NREGIONS * sizeof (int))];
+
+  memset (&mh, 0, sizeof (mh));
+  memset (control, 0, sizeof (control));
+
+  for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++)
+    fds[i] = -1;
+
+  /* set the payload */
+  iov[0].iov_base = (void *) &msg;
+  iov[0].iov_len = VHOST_USER_MSG_HDR_SZ;
+
+  mh.msg_iov = iov;
+  mh.msg_iovlen = 1;
+  mh.msg_control = control;
+  mh.msg_controllen = sizeof (control);
+
+  n = recvmsg (uf->file_descriptor, &mh, 0);
+
+  /* Stop workers to avoid end of the world */
+  vlib_worker_thread_barrier_sync (vlib_get_main ());
+
+  if (n != VHOST_USER_MSG_HDR_SZ)
+    {
+      if (n == -1)
+	{
+	  DBG_SOCK ("recvmsg returned error %d %s", errno, strerror (errno));
+	}
+      else
+	{
+	  DBG_SOCK ("n (%d) != VHOST_USER_MSG_HDR_SZ (%d)",
+		    n, VHOST_USER_MSG_HDR_SZ);
+	}
+      goto close_socket;
+    }
+
+  if (mh.msg_flags & MSG_CTRUNC)
+    {
+      DBG_SOCK ("MSG_CTRUNC is set");
+      goto close_socket;
+    }
+
+  cmsg = CMSG_FIRSTHDR (&mh);
+
+  if (cmsg && (cmsg->cmsg_len > 0) && (cmsg->cmsg_level == SOL_SOCKET) &&
+      (cmsg->cmsg_type == SCM_RIGHTS) &&
+      (cmsg->cmsg_len - CMSG_LEN (0) <=
+       VHOST_MEMORY_MAX_NREGIONS * sizeof (int)))
+    {
+      number_of_fds = (cmsg->cmsg_len - CMSG_LEN (0)) / sizeof (int);
+      clib_memcpy (fds, CMSG_DATA (cmsg), number_of_fds * sizeof (int));
+    }
+
+  /* version 1, no reply bit set */
+  if ((msg.flags & 7) != 1)
+    {
+      DBG_SOCK ("malformed message received. closing socket");
+      goto close_socket;
+    }
+
+  {
+    int rv;
+    rv =
+      read (uf->file_descriptor, ((char *) &msg) + VHOST_USER_MSG_HDR_SZ,
+	    msg.size);
+    if (rv < 0)
+      {
+	DBG_SOCK ("read failed %s", strerror (errno));
+	goto close_socket;
+      }
+    else if (rv != msg.size)
+      {
+	DBG_SOCK ("message too short (read %dB should be %dB)", rv, msg.size);
+	goto close_socket;
+      }
+  }
+
+  switch (msg.request)
+    {
+    case VHOST_USER_GET_FEATURES:
+      msg.flags |= 4;
+      msg.u64 = (1ULL << FEAT_VIRTIO_NET_F_MRG_RXBUF) |
+	(1ULL << FEAT_VIRTIO_NET_F_CTRL_VQ) |
+	(1ULL << FEAT_VIRTIO_F_ANY_LAYOUT) |
+	(1ULL << FEAT_VIRTIO_F_INDIRECT_DESC) |
+	(1ULL << FEAT_VHOST_F_LOG_ALL) |
+	(1ULL << FEAT_VIRTIO_NET_F_GUEST_ANNOUNCE) |
+	(1ULL << FEAT_VIRTIO_NET_F_MQ) |
+	(1ULL << FEAT_VHOST_USER_F_PROTOCOL_FEATURES) |
+	(1ULL << FEAT_VIRTIO_F_VERSION_1);
+      msg.u64 &= vui->feature_mask;
+      msg.size = sizeof (msg.u64);
+      DBG_SOCK ("if %d msg VHOST_USER_GET_FEATURES - reply 0x%016llx",
+		vui->hw_if_index, msg.u64);
+      break;
+
+    case VHOST_USER_SET_FEATURES:
+      DBG_SOCK ("if %d msg VHOST_USER_SET_FEATURES features 0x%016llx",
+		vui->hw_if_index, msg.u64);
+
+      vui->features = msg.u64;
+
+      if (vui->features &
+	  ((1 << FEAT_VIRTIO_NET_F_MRG_RXBUF) |
+	   (1ULL << FEAT_VIRTIO_F_VERSION_1)))
+	vui->virtio_net_hdr_sz = 12;
+      else
+	vui->virtio_net_hdr_sz = 10;
+
+      vui->is_any_layout =
+	(vui->features & (1 << FEAT_VIRTIO_F_ANY_LAYOUT)) ? 1 : 0;
+
+      ASSERT (vui->virtio_net_hdr_sz < VLIB_BUFFER_PRE_DATA_SIZE);
+      vnet_hw_interface_set_flags (vnm, vui->hw_if_index, 0);
+      vui->is_up = 0;
+
+      /*for (q = 0; q < VHOST_VRING_MAX_N; q++)
+         vhost_user_vring_close(&vui->vrings[q]); */
+
+      break;
+
+    case VHOST_USER_SET_MEM_TABLE:
+      DBG_SOCK ("if %d msg VHOST_USER_SET_MEM_TABLE nregions %d",
+		vui->hw_if_index, msg.memory.nregions);
+
+      if ((msg.memory.nregions < 1) ||
+	  (msg.memory.nregions > VHOST_MEMORY_MAX_NREGIONS))
+	{
+
+	  DBG_SOCK ("number of mem regions must be between 1 and %i",
+		    VHOST_MEMORY_MAX_NREGIONS);
+
+	  goto close_socket;
+	}
+
+      if (msg.memory.nregions != number_of_fds)
+	{
+	  DBG_SOCK ("each memory region must have FD");
+	  goto close_socket;
+	}
+      unmap_all_mem_regions (vui);
+      for (i = 0; i < msg.memory.nregions; i++)
+	{
+	  clib_memcpy (&(vui->regions[i]), &msg.memory.regions[i],
+		       sizeof (vhost_user_memory_region_t));
+
+	  long page_sz = get_huge_page_size (fds[i]);
+
+	  /* align size to page */
+	  ssize_t map_sz = (vui->regions[i].memory_size +
+			    vui->regions[i].mmap_offset +
+			    page_sz - 1) & ~(page_sz - 1);
+
+	  vui->region_mmap_addr[i] = mmap (0, map_sz, PROT_READ | PROT_WRITE,
+					   MAP_SHARED, fds[i], 0);
+	  vui->region_guest_addr_lo[i] = vui->regions[i].guest_phys_addr;
+	  vui->region_guest_addr_hi[i] = vui->regions[i].guest_phys_addr +
+	    vui->regions[i].memory_size;
+
+	  DBG_SOCK
+	    ("map memory region %d addr 0 len 0x%lx fd %d mapped 0x%lx "
+	     "page_sz 0x%x", i, map_sz, fds[i], vui->region_mmap_addr[i],
+	     page_sz);
+
+	  if (vui->region_mmap_addr[i] == MAP_FAILED)
+	    {
+	      clib_warning ("failed to map memory. errno is %d", errno);
+	      goto close_socket;
+	    }
+	  vui->region_mmap_addr[i] += vui->regions[i].mmap_offset;
+	  vui->region_mmap_fd[i] = fds[i];
+
+	  vui->nregions++;
+	}
+      break;
+
+    case VHOST_USER_SET_VRING_NUM:
+      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_NUM idx %d num %d",
+		vui->hw_if_index, msg.state.index, msg.state.num);
+
+      if ((msg.state.num > 32768) ||	/* maximum ring size is 32768 */
+	  (msg.state.num == 0) ||	/* it cannot be zero */
+	  ((msg.state.num - 1) & msg.state.num))	/* must be power of 2 */
+	goto close_socket;
+      vui->vrings[msg.state.index].qsz_mask = msg.state.num - 1;
+      break;
+
+    case VHOST_USER_SET_VRING_ADDR:
+      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_ADDR idx %d",
+		vui->hw_if_index, msg.state.index);
+
+      if (msg.state.index >= VHOST_VRING_MAX_N)
+	{
+	  DBG_SOCK ("invalid vring index VHOST_USER_SET_VRING_ADDR:"
+		    " %d >= %d", msg.state.index, VHOST_VRING_MAX_N);
+	  goto close_socket;
+	}
+
+      if (msg.size < sizeof (msg.addr))
+	{
+	  DBG_SOCK ("vhost message is too short (%d < %d)",
+		    msg.size, sizeof (msg.addr));
+	  goto close_socket;
+	}
+
+      vui->vrings[msg.state.index].desc = (vring_desc_t *)
+	map_user_mem (vui, msg.addr.desc_user_addr);
+      vui->vrings[msg.state.index].used = (vring_used_t *)
+	map_user_mem (vui, msg.addr.used_user_addr);
+      vui->vrings[msg.state.index].avail = (vring_avail_t *)
+	map_user_mem (vui, msg.addr.avail_user_addr);
+
+      if ((vui->vrings[msg.state.index].desc == NULL) ||
+	  (vui->vrings[msg.state.index].used == NULL) ||
+	  (vui->vrings[msg.state.index].avail == NULL))
+	{
+	  DBG_SOCK ("failed to map user memory for hw_if_index %d",
+		    vui->hw_if_index);
+	  goto close_socket;
+	}
+
+      vui->vrings[msg.state.index].log_guest_addr = msg.addr.log_guest_addr;
+      vui->vrings[msg.state.index].log_used =
+	(msg.addr.flags & (1 << VHOST_VRING_F_LOG)) ? 1 : 0;
+
+      /* Spec says: If VHOST_USER_F_PROTOCOL_FEATURES has not been negotiated,
+         the ring is initialized in an enabled state. */
+      if (!(vui->features & (1 << FEAT_VHOST_USER_F_PROTOCOL_FEATURES)))
+	{
+	  vui->vrings[msg.state.index].enabled = 1;
+	}
+
+      vui->vrings[msg.state.index].last_used_idx =
+	vui->vrings[msg.state.index].last_avail_idx =
+	vui->vrings[msg.state.index].used->idx;
+
+      /* tell driver that we don't want interrupts */
+      vui->vrings[msg.state.index].used->flags = VRING_USED_F_NO_NOTIFY;
+      break;
+
+    case VHOST_USER_SET_OWNER:
+      DBG_SOCK ("if %d msg VHOST_USER_SET_OWNER", vui->hw_if_index);
+      break;
+
+    case VHOST_USER_RESET_OWNER:
+      DBG_SOCK ("if %d msg VHOST_USER_RESET_OWNER", vui->hw_if_index);
+      break;
+
+    case VHOST_USER_SET_VRING_CALL:
+      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_CALL %d",
+		vui->hw_if_index, msg.u64);
+
+      q = (u8) (msg.u64 & 0xFF);
+
+      /* if there is old fd, delete and close it */
+      if (vui->vrings[q].callfd_idx != ~0)
+	{
+	  clib_file_t *uf = pool_elt_at_index (file_main.file_pool,
+					       vui->vrings[q].callfd_idx);
+	  clib_file_del (&file_main, uf);
+	  vui->vrings[q].callfd_idx = ~0;
+	}
+
+      if (!(msg.u64 & VHOST_USER_VRING_NOFD_MASK))
+	{
+	  if (number_of_fds != 1)
+	    {
+	      DBG_SOCK ("More than one fd received !");
+	      goto close_socket;
+	    }
+
+	  template.read_function = vhost_user_callfd_read_ready;
+	  template.file_descriptor = fds[0];
+	  template.private_data =
+	    ((vui - vhost_user_main.vhost_user_interfaces) << 8) + q;
+	  vui->vrings[q].callfd_idx = clib_file_add (&file_main, &template);
+	}
+      else
+	vui->vrings[q].callfd_idx = ~0;
+      break;
+
+    case VHOST_USER_SET_VRING_KICK:
+      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_KICK %d",
+		vui->hw_if_index, msg.u64);
+
+      q = (u8) (msg.u64 & 0xFF);
+
+      if (vui->vrings[q].kickfd_idx != ~0)
+	{
+	  clib_file_t *uf = pool_elt_at_index (file_main.file_pool,
+					       vui->vrings[q].kickfd_idx);
+	  clib_file_del (&file_main, uf);
+	  vui->vrings[q].kickfd_idx = ~0;
+	}
+
+      if (!(msg.u64 & VHOST_USER_VRING_NOFD_MASK))
+	{
+	  if (number_of_fds != 1)
+	    {
+	      DBG_SOCK ("More than one fd received !");
+	      goto close_socket;
+	    }
+
+	  template.read_function = vhost_user_kickfd_read_ready;
+	  template.file_descriptor = fds[0];
+	  template.private_data =
+	    (((uword) (vui - vhost_user_main.vhost_user_interfaces)) << 8) +
+	    q;
+	  vui->vrings[q].kickfd_idx = clib_file_add (&file_main, &template);
+	}
+      else
+	{
+	  //When no kickfd is set, the queue is initialized as started
+	  vui->vrings[q].kickfd_idx = ~0;
+	  vui->vrings[q].started = 1;
+	}
+
+      break;
+
+    case VHOST_USER_SET_VRING_ERR:
+      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_ERR %d",
+		vui->hw_if_index, msg.u64);
+
+      q = (u8) (msg.u64 & 0xFF);
+
+      if (vui->vrings[q].errfd != -1)
+	close (vui->vrings[q].errfd);
+
+      if (!(msg.u64 & VHOST_USER_VRING_NOFD_MASK))
+	{
+	  if (number_of_fds != 1)
+	    goto close_socket;
+
+	  vui->vrings[q].errfd = fds[0];
+	}
+      else
+	vui->vrings[q].errfd = -1;
+
+      break;
+
+    case VHOST_USER_SET_VRING_BASE:
+      DBG_SOCK ("if %d msg VHOST_USER_SET_VRING_BASE idx %d num %d",
+		vui->hw_if_index, msg.state.index, msg.state.num);
+
+      vui->vrings[msg.state.index].last_avail_idx = msg.state.num;
+      break;
+
+    case VHOST_USER_GET_VRING_BASE:
+      if (msg.state.index >= VHOST_VRING_MAX_N)
+	{
+	  DBG_SOCK ("invalid vring index VHOST_USER_GET_VRING_BASE:"
+		    " %d >= %d", msg.state.index, VHOST_VRING_MAX_N);
+	  goto close_socket;
+	}
+
+      /*
+       * Copy last_avail_idx from the vring before closing it because
+       * closing the vring also initializes the vring last_avail_idx
+       */
+      msg.state.num = vui->vrings[msg.state.index].last_avail_idx;
+      msg.flags |= 4;
+      msg.size = sizeof (msg.state);
+
+      /* Spec says: Client must [...] stop ring upon receiving VHOST_USER_GET_VRING_BASE. */
+      vhost_user_vring_close (vui, msg.state.index);
+      DBG_SOCK ("if %d msg VHOST_USER_GET_VRING_BASE idx %d num %d",
+		vui->hw_if_index, msg.state.index, msg.state.num);
+      break;
+
+    case VHOST_USER_NONE:
+      DBG_SOCK ("if %d msg VHOST_USER_NONE", vui->hw_if_index);
+
+      break;
+
+    case VHOST_USER_SET_LOG_BASE:
+      {
+	DBG_SOCK ("if %d msg VHOST_USER_SET_LOG_BASE", vui->hw_if_index);
+
+	if (msg.size != sizeof (msg.log))
+	  {
+	    DBG_SOCK
+	      ("invalid msg size for VHOST_USER_SET_LOG_BASE: %d instead of %d",
+	       msg.size, sizeof (msg.log));
+	    goto close_socket;
+	  }
+
+	if (!
+	    (vui->protocol_features & (1 << VHOST_USER_PROTOCOL_F_LOG_SHMFD)))
+	  {
+	    DBG_SOCK
+	      ("VHOST_USER_PROTOCOL_F_LOG_SHMFD not set but VHOST_USER_SET_LOG_BASE received");
+	    goto close_socket;
+	  }
+
+	fd = fds[0];
+	/* align size to page */
+	long page_sz = get_huge_page_size (fd);
+	ssize_t map_sz =
+	  (msg.log.size + msg.log.offset + page_sz - 1) & ~(page_sz - 1);
+
+	vui->log_base_addr = mmap (0, map_sz, PROT_READ | PROT_WRITE,
+				   MAP_SHARED, fd, 0);
+
+	DBG_SOCK
+	  ("map log region addr 0 len 0x%lx off 0x%lx fd %d mapped 0x%lx",
+	   map_sz, msg.log.offset, fd, vui->log_base_addr);
+
+	if (vui->log_base_addr == MAP_FAILED)
+	  {
+	    clib_warning ("failed to map memory. errno is %d", errno);
+	    goto close_socket;
+	  }
+
+	vui->log_base_addr += msg.log.offset;
+	vui->log_size = msg.log.size;
+
+	msg.flags |= 4;
+	msg.size = sizeof (msg.u64);
+
+	break;
+      }
+
+    case VHOST_USER_SET_LOG_FD:
+      DBG_SOCK ("if %d msg VHOST_USER_SET_LOG_FD", vui->hw_if_index);
+
+      break;
+
+    case VHOST_USER_GET_PROTOCOL_FEATURES:
+      msg.flags |= 4;
+      msg.u64 = (1 << VHOST_USER_PROTOCOL_F_LOG_SHMFD) |
+	(1 << VHOST_USER_PROTOCOL_F_MQ);
+      msg.size = sizeof (msg.u64);
+      DBG_SOCK
+	("if %d msg VHOST_USER_GET_PROTOCOL_FEATURES - reply 0x%016llx",
+	 vui->hw_if_index, msg.u64);
+      break;
+
+    case VHOST_USER_SET_PROTOCOL_FEATURES:
+      DBG_SOCK
+	("if %d msg VHOST_USER_SET_PROTOCOL_FEATURES features 0x%016llx",
+	 vui->hw_if_index, msg.u64);
+
+      vui->protocol_features = msg.u64;
+
+      break;
+
+    case VHOST_USER_GET_QUEUE_NUM:
+      msg.flags |= 4;
+      msg.u64 = VHOST_VRING_MAX_N;
+      msg.size = sizeof (msg.u64);
+      DBG_SOCK ("if %d msg VHOST_USER_GET_QUEUE_NUM - reply %d",
+		vui->hw_if_index, msg.u64);
+      break;
+
+    case VHOST_USER_SET_VRING_ENABLE:
+      DBG_SOCK ("if %d VHOST_USER_SET_VRING_ENABLE: %s queue %d",
+		vui->hw_if_index, msg.state.num ? "enable" : "disable",
+		msg.state.index);
+      if (msg.state.index >= VHOST_VRING_MAX_N)
+	{
+	  DBG_SOCK ("invalid vring index VHOST_USER_SET_VRING_ENABLE:"
+		    " %d >= %d", msg.state.index, VHOST_VRING_MAX_N);
+	  goto close_socket;
+	}
+
+      vui->vrings[msg.state.index].enabled = msg.state.num;
+      break;
+
+    default:
+      DBG_SOCK ("unknown vhost-user message %d received. closing socket",
+		msg.request);
+      goto close_socket;
+    }
+
+  /* if we need to reply */
+  if (msg.flags & 4)
+    {
+      n =
+	send (uf->file_descriptor, &msg, VHOST_USER_MSG_HDR_SZ + msg.size, 0);
+      if (n != (msg.size + VHOST_USER_MSG_HDR_SZ))
+	{
+	  DBG_SOCK ("could not send message response");
+	  goto close_socket;
+	}
+    }
+
+  vhost_user_update_iface_state (vui);
+  vlib_worker_thread_barrier_release (vlib_get_main ());
+  return 0;
+
+close_socket:
+  vhost_user_if_disconnect (vui);
+  vhost_user_update_iface_state (vui);
+  vlib_worker_thread_barrier_release (vlib_get_main ());
+  return 0;
+}
+
+static clib_error_t *
+vhost_user_socket_error (clib_file_t * uf)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui =
+    pool_elt_at_index (vum->vhost_user_interfaces, uf->private_data);
+
+  DBG_SOCK ("socket error on if %d", vui->sw_if_index);
+  vlib_worker_thread_barrier_sync (vm);
+  vhost_user_if_disconnect (vui);
+  vhost_user_rx_thread_placement ();
+  vlib_worker_thread_barrier_release (vm);
+  return 0;
+}
+
+static clib_error_t *
+vhost_user_socksvr_accept_ready (clib_file_t * uf)
+{
+  int client_fd, client_len;
+  struct sockaddr_un client;
+  clib_file_t template = { 0 };
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui;
+
+  vui = pool_elt_at_index (vum->vhost_user_interfaces, uf->private_data);
+
+  client_len = sizeof (client);
+  client_fd = accept (uf->file_descriptor,
+		      (struct sockaddr *) &client,
+		      (socklen_t *) & client_len);
+
+  if (client_fd < 0)
+    return clib_error_return_unix (0, "accept");
+
+  if (vui->clib_file_index != ~0)
+    {
+      DBG_SOCK ("Close client socket for vhost interface %d, fd %d",
+		vui->sw_if_index, UNIX_GET_FD (vui->clib_file_index));
+      clib_file_del (&file_main, file_main.file_pool + vui->clib_file_index);
+    }
+
+  DBG_SOCK ("New client socket for vhost interface %d, fd %d",
+	    vui->sw_if_index, client_fd);
+  template.read_function = vhost_user_socket_read;
+  template.error_function = vhost_user_socket_error;
+  template.file_descriptor = client_fd;
+  template.private_data = vui - vhost_user_main.vhost_user_interfaces;
+  vui->clib_file_index = clib_file_add (&file_main, &template);
+  return 0;
+}
+
+static clib_error_t *
+vhost_user_init (vlib_main_t * vm)
+{
+  clib_error_t *error;
+  vhost_user_main_t *vum = &vhost_user_main;
+  vlib_thread_main_t *tm = vlib_get_thread_main ();
+
+  error = vlib_call_init_function (vm, ip4_init);
+  if (error)
+    return error;
+
+  vum->coalesce_frames = 32;
+  vum->coalesce_time = 1e-3;
+
+  vec_validate (vum->cpus, tm->n_vlib_mains - 1);
+
+  vhost_cpu_t *cpu;
+  vec_foreach (cpu, vum->cpus)
+  {
+    /* This is actually not necessary as validate already zeroes it
+     * Just keeping the loop here for later because I am lazy. */
+    cpu->rx_buffers_len = 0;
+  }
+
+  vum->random = random_default_seed ();
+
+  mhash_init_c_string (&vum->if_index_by_sock_name, sizeof (uword));
+
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (vhost_user_init);
+
+static uword
+vhost_user_send_interrupt_process (vlib_main_t * vm,
+				   vlib_node_runtime_t * rt, vlib_frame_t * f)
+{
+  vhost_user_intf_t *vui;
+  f64 timeout = 3153600000.0 /* 100 years */ ;
+  uword event_type, *event_data = 0;
+  vhost_user_main_t *vum = &vhost_user_main;
+  u16 *queue;
+  f64 now, poll_time_remaining;
+  f64 next_timeout;
+  u8 stop_timer = 0;
+
+  while (1)
+    {
+      poll_time_remaining =
+	vlib_process_wait_for_event_or_clock (vm, timeout);
+      event_type = vlib_process_get_events (vm, &event_data);
+      vec_reset_length (event_data);
+
+      /*
+       * Use the remaining timeout if it is less than coalesce time to avoid
+       * resetting the existing timer in the middle of expiration
+       */
+      timeout = poll_time_remaining;
+      if (vlib_process_suspend_time_is_zero (timeout) ||
+	  (timeout > vum->coalesce_time))
+	timeout = vum->coalesce_time;
+
+      now = vlib_time_now (vm);
+      switch (event_type)
+	{
+	case VHOST_USER_EVENT_STOP_TIMER:
+	  stop_timer = 1;
+	  break;
+
+	case VHOST_USER_EVENT_START_TIMER:
+	  stop_timer = 0;
+	  if (!vlib_process_suspend_time_is_zero (poll_time_remaining))
+	    break;
+	  /* fall through */
+
+	case ~0:
+	  /* *INDENT-OFF* */
+	  pool_foreach (vui, vum->vhost_user_interfaces, {
+	      next_timeout = timeout;
+	      vec_foreach (queue, vui->rx_queues)
+		{
+		  vhost_user_vring_t *rxvq =
+		    &vui->vrings[VHOST_VRING_IDX_RX (*queue)];
+		  vhost_user_vring_t *txvq =
+		    &vui->vrings[VHOST_VRING_IDX_TX (*queue)];
+
+		  if (txvq->n_since_last_int)
+		    {
+		      if (now >= txvq->int_deadline)
+			vhost_user_send_call (vm, txvq);
+		      else
+			next_timeout = txvq->int_deadline - now;
+		    }
+
+		  if (rxvq->n_since_last_int)
+		    {
+		      if (now >= rxvq->int_deadline)
+			vhost_user_send_call (vm, rxvq);
+		      else
+			next_timeout = rxvq->int_deadline - now;
+		    }
+
+		  if ((next_timeout < timeout) && (next_timeout > 0.0))
+		    timeout = next_timeout;
+		}
+	  });
+          /* *INDENT-ON* */
+	  break;
+
+	default:
+	  clib_warning ("BUG: unhandled event type %d", event_type);
+	  break;
+	}
+      /* No less than 1 millisecond */
+      if (timeout < 1e-3)
+	timeout = 1e-3;
+      if (stop_timer)
+	timeout = 3153600000.0;
+    }
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (vhost_user_send_interrupt_node) = {
+    .function = vhost_user_send_interrupt_process,
+    .type = VLIB_NODE_TYPE_PROCESS,
+    .name = "vhost-user-send-interrupt-process",
+};
+/* *INDENT-ON* */
+
+static uword
+vhost_user_process (vlib_main_t * vm,
+		    vlib_node_runtime_t * rt, vlib_frame_t * f)
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui;
+  struct sockaddr_un sun;
+  int sockfd;
+  clib_file_t template = { 0 };
+  f64 timeout = 3153600000.0 /* 100 years */ ;
+  uword *event_data = 0;
+
+  sockfd = -1;
+  sun.sun_family = AF_UNIX;
+  template.read_function = vhost_user_socket_read;
+  template.error_function = vhost_user_socket_error;
+
+  while (1)
+    {
+      vlib_process_wait_for_event_or_clock (vm, timeout);
+      vlib_process_get_events (vm, &event_data);
+      vec_reset_length (event_data);
+
+      timeout = 3.0;
+
+      /* *INDENT-OFF* */
+      pool_foreach (vui, vum->vhost_user_interfaces, {
+
+	  if (vui->unix_server_index == ~0) { //Nothing to do for server sockets
+	      if (vui->clib_file_index == ~0)
+		{
+		  if ((sockfd < 0) &&
+		      ((sockfd = socket (AF_UNIX, SOCK_STREAM, 0)) < 0))
+		    {
+		      /*
+		       * 1st time error or new error for this interface,
+		       * spit out the message and record the error
+		       */
+		      if (!vui->sock_errno || (vui->sock_errno != errno))
+			{
+			  clib_unix_warning
+			    ("Error: Could not open unix socket for %s",
+			     vui->sock_filename);
+			  vui->sock_errno = errno;
+			}
+		      continue;
+		    }
+
+		  /* try to connect */
+		  strncpy (sun.sun_path, (char *) vui->sock_filename,
+			   sizeof (sun.sun_path) - 1);
+
+		  /* Avoid hanging VPP if the other end does not accept */
+		  if (fcntl(sockfd, F_SETFL, O_NONBLOCK) < 0)
+                      clib_unix_warning ("fcntl");
+
+		  if (connect (sockfd, (struct sockaddr *) &sun,
+			       sizeof (struct sockaddr_un)) == 0)
+		    {
+		      /* Set the socket to blocking as it was before */
+                      if (fcntl(sockfd, F_SETFL, 0) < 0)
+                        clib_unix_warning ("fcntl2");
+
+		      vui->sock_errno = 0;
+		      template.file_descriptor = sockfd;
+		      template.private_data =
+			  vui - vhost_user_main.vhost_user_interfaces;
+		      vui->clib_file_index = clib_file_add (&file_main, &template);
+
+		      /* This sockfd is considered consumed */
+		      sockfd = -1;
+		    }
+		  else
+		    {
+		      vui->sock_errno = errno;
+		    }
+		}
+	      else
+		{
+		  /* check if socket is alive */
+		  int error = 0;
+		  socklen_t len = sizeof (error);
+		  int fd = UNIX_GET_FD(vui->clib_file_index);
+		  int retval =
+		      getsockopt (fd, SOL_SOCKET, SO_ERROR, &error, &len);
+
+		  if (retval)
+		    {
+		      DBG_SOCK ("getsockopt returned %d", retval);
+		      vhost_user_if_disconnect (vui);
+		    }
+		}
+	  }
+      });
+      /* *INDENT-ON* */
+    }
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (vhost_user_process_node,static) = {
+    .function = vhost_user_process,
+    .type = VLIB_NODE_TYPE_PROCESS,
+    .name = "vhost-user-process",
+};
+/* *INDENT-ON* */
+
+/**
+ * Disables and reset interface structure.
+ * It can then be either init again, or removed from used interfaces.
+ */
+static void
+vhost_user_term_if (vhost_user_intf_t * vui)
+{
+  int q;
+  vhost_user_main_t *vum = &vhost_user_main;
+
+  // disconnect interface sockets
+  vhost_user_if_disconnect (vui);
+  vhost_user_update_iface_state (vui);
+
+  for (q = 0; q < VHOST_VRING_MAX_N; q++)
+    {
+      clib_mem_free ((void *) vui->vring_locks[q]);
+    }
+
+  if (vui->unix_server_index != ~0)
+    {
+      //Close server socket
+      clib_file_t *uf = pool_elt_at_index (file_main.file_pool,
+					   vui->unix_server_index);
+      clib_file_del (&file_main, uf);
+      vui->unix_server_index = ~0;
+      unlink (vui->sock_filename);
+    }
+
+  mhash_unset (&vum->if_index_by_sock_name, vui->sock_filename,
+	       &vui->if_index);
+}
+
+int
+vhost_user_delete_if (vnet_main_t * vnm, vlib_main_t * vm, u32 sw_if_index)
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui;
+  int rv = 0;
+  vnet_hw_interface_t *hwif;
+  u16 *queue;
+
+  if (!(hwif = vnet_get_sup_hw_interface (vnm, sw_if_index)) ||
+      hwif->dev_class_index != vhost_user_device_class.index)
+    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
+
+  DBG_SOCK ("Deleting vhost-user interface %s (instance %d)",
+	    hwif->name, hwif->dev_instance);
+
+  vui = pool_elt_at_index (vum->vhost_user_interfaces, hwif->dev_instance);
+
+  vec_foreach (queue, vui->rx_queues)
+  {
+    vhost_user_vring_t *txvq;
+
+    txvq = &vui->vrings[VHOST_VRING_IDX_TX (*queue)];
+    if ((vum->ifq_count > 0) &&
+	((txvq->mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT) ||
+	 (txvq->mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE)))
+      {
+	vum->ifq_count--;
+	// Stop the timer if there is no more interrupt interface/queue
+	if ((vum->ifq_count == 0) &&
+	    (vum->coalesce_time > 0.0) && (vum->coalesce_frames > 0))
+	  {
+	    vlib_process_signal_event (vm,
+				       vhost_user_send_interrupt_node.index,
+				       VHOST_USER_EVENT_STOP_TIMER, 0);
+	    break;
+	  }
+      }
+  }
+
+  // Disable and reset interface
+  vhost_user_term_if (vui);
+
+  // Reset renumbered iface
+  if (hwif->dev_instance <
+      vec_len (vum->show_dev_instance_by_real_dev_instance))
+    vum->show_dev_instance_by_real_dev_instance[hwif->dev_instance] = ~0;
+
+  // Delete ethernet interface
+  ethernet_delete_interface (vnm, vui->hw_if_index);
+
+  // Back to pool
+  pool_put (vum->vhost_user_interfaces, vui);
+
+  return rv;
+}
+
+static clib_error_t *
+vhost_user_exit (vlib_main_t * vm)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui;
+
+  vlib_worker_thread_barrier_sync (vlib_get_main ());
+  /* *INDENT-OFF* */
+  pool_foreach (vui, vum->vhost_user_interfaces, {
+      vhost_user_delete_if (vnm, vm, vui->sw_if_index);
+  });
+  /* *INDENT-ON* */
+  vlib_worker_thread_barrier_release (vlib_get_main ());
+  return 0;
+}
+
+VLIB_MAIN_LOOP_EXIT_FUNCTION (vhost_user_exit);
+
+/**
+ * Open server unix socket on specified sock_filename.
+ */
+static int
+vhost_user_init_server_sock (const char *sock_filename, int *sock_fd)
+{
+  int rv = 0;
+  struct sockaddr_un un = { };
+  int fd;
+  /* create listening socket */
+  if ((fd = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
+    return VNET_API_ERROR_SYSCALL_ERROR_1;
+
+  un.sun_family = AF_UNIX;
+  strncpy ((char *) un.sun_path, (char *) sock_filename,
+	   sizeof (un.sun_path) - 1);
+
+  /* remove if exists */
+  unlink ((char *) sock_filename);
+
+  if (bind (fd, (struct sockaddr *) &un, sizeof (un)) == -1)
+    {
+      rv = VNET_API_ERROR_SYSCALL_ERROR_2;
+      goto error;
+    }
+
+  if (listen (fd, 1) == -1)
+    {
+      rv = VNET_API_ERROR_SYSCALL_ERROR_3;
+      goto error;
+    }
+
+  *sock_fd = fd;
+  return 0;
+
+error:
+  close (fd);
+  return rv;
+}
+
+/**
+ * Create ethernet interface for vhost user interface.
+ */
+static void
+vhost_user_create_ethernet (vnet_main_t * vnm, vlib_main_t * vm,
+			    vhost_user_intf_t * vui, u8 * hwaddress)
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+  u8 hwaddr[6];
+  clib_error_t *error;
+
+  /* create hw and sw interface */
+  if (hwaddress)
+    {
+      clib_memcpy (hwaddr, hwaddress, 6);
+    }
+  else
+    {
+      random_u32 (&vum->random);
+      clib_memcpy (hwaddr + 2, &vum->random, sizeof (vum->random));
+      hwaddr[0] = 2;
+      hwaddr[1] = 0xfe;
+    }
+
+  error = ethernet_register_interface
+    (vnm,
+     vhost_user_device_class.index,
+     vui - vum->vhost_user_interfaces /* device instance */ ,
+     hwaddr /* ethernet address */ ,
+     &vui->hw_if_index, 0 /* flag change */ );
+
+  if (error)
+    clib_error_report (error);
+
+  vnet_sw_interface_set_mtu (vnm, vui->sw_if_index, 9000);
+}
+
+/*
+ *  Initialize vui with specified attributes
+ */
+static void
+vhost_user_vui_init (vnet_main_t * vnm,
+		     vhost_user_intf_t * vui,
+		     int server_sock_fd,
+		     const char *sock_filename,
+		     u64 feature_mask, u32 * sw_if_index)
+{
+  vnet_sw_interface_t *sw;
+  int q;
+  vhost_user_main_t *vum = &vhost_user_main;
+  vnet_hw_interface_t *hw;
+
+  hw = vnet_get_hw_interface (vnm, vui->hw_if_index);
+  sw = vnet_get_hw_sw_interface (vnm, vui->hw_if_index);
+  if (server_sock_fd != -1)
+    {
+      clib_file_t template = { 0 };
+      template.read_function = vhost_user_socksvr_accept_ready;
+      template.file_descriptor = server_sock_fd;
+      template.private_data = vui - vum->vhost_user_interfaces;	//hw index
+      vui->unix_server_index = clib_file_add (&file_main, &template);
+    }
+  else
+    {
+      vui->unix_server_index = ~0;
+    }
+
+  vui->sw_if_index = sw->sw_if_index;
+  strncpy (vui->sock_filename, sock_filename,
+	   ARRAY_LEN (vui->sock_filename) - 1);
+  vui->sock_errno = 0;
+  vui->is_up = 0;
+  vui->feature_mask = feature_mask;
+  vui->clib_file_index = ~0;
+  vui->log_base_addr = 0;
+  vui->if_index = vui - vum->vhost_user_interfaces;
+  mhash_set_mem (&vum->if_index_by_sock_name, vui->sock_filename,
+		 &vui->if_index, 0);
+
+  for (q = 0; q < VHOST_VRING_MAX_N; q++)
+    vhost_user_vring_init (vui, q);
+
+  hw->flags |= VNET_HW_INTERFACE_FLAG_SUPPORTS_INT_MODE;
+  vnet_hw_interface_set_flags (vnm, vui->hw_if_index, 0);
+
+  if (sw_if_index)
+    *sw_if_index = vui->sw_if_index;
+
+  for (q = 0; q < VHOST_VRING_MAX_N; q++)
+    {
+      vui->vring_locks[q] = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES,
+						    CLIB_CACHE_LINE_BYTES);
+      memset ((void *) vui->vring_locks[q], 0, CLIB_CACHE_LINE_BYTES);
+    }
+
+  vec_validate (vui->per_cpu_tx_qid,
+		vlib_get_thread_main ()->n_vlib_mains - 1);
+  vhost_user_tx_thread_placement (vui);
+}
+
+int
+vhost_user_create_if (vnet_main_t * vnm, vlib_main_t * vm,
+		      const char *sock_filename,
+		      u8 is_server,
+		      u32 * sw_if_index,
+		      u64 feature_mask,
+		      u8 renumber, u32 custom_dev_instance, u8 * hwaddr)
+{
+  vhost_user_intf_t *vui = NULL;
+  u32 sw_if_idx = ~0;
+  int rv = 0;
+  int server_sock_fd = -1;
+  vhost_user_main_t *vum = &vhost_user_main;
+  uword *if_index;
+
+  if (sock_filename == NULL || !(strlen (sock_filename) > 0))
+    {
+      return VNET_API_ERROR_INVALID_ARGUMENT;
+    }
+
+  if_index = mhash_get (&vum->if_index_by_sock_name, (void *) sock_filename);
+  if (if_index)
+    {
+      if (sw_if_index)
+	{
+	  vui = &vum->vhost_user_interfaces[*if_index];
+	  *sw_if_index = vui->sw_if_index;
+	}
+      return VNET_API_ERROR_IF_ALREADY_EXISTS;
+    }
+
+  if (is_server)
+    {
+      if ((rv =
+	   vhost_user_init_server_sock (sock_filename, &server_sock_fd)) != 0)
+	{
+	  return rv;
+	}
+    }
+
+  pool_get (vhost_user_main.vhost_user_interfaces, vui);
+
+  vhost_user_create_ethernet (vnm, vm, vui, hwaddr);
+  vhost_user_vui_init (vnm, vui, server_sock_fd, sock_filename,
+		       feature_mask, &sw_if_idx);
+
+  if (renumber)
+    vnet_interface_name_renumber (sw_if_idx, custom_dev_instance);
+
+  if (sw_if_index)
+    *sw_if_index = sw_if_idx;
+
+  // Process node must connect
+  vlib_process_signal_event (vm, vhost_user_process_node.index, 0, 0);
+
+  return rv;
+}
+
+int
+vhost_user_modify_if (vnet_main_t * vnm, vlib_main_t * vm,
+		      const char *sock_filename,
+		      u8 is_server,
+		      u32 sw_if_index,
+		      u64 feature_mask, u8 renumber, u32 custom_dev_instance)
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui = NULL;
+  u32 sw_if_idx = ~0;
+  int server_sock_fd = -1;
+  int rv = 0;
+  vnet_hw_interface_t *hwif;
+  uword *if_index;
+
+  if (!(hwif = vnet_get_sup_hw_interface (vnm, sw_if_index)) ||
+      hwif->dev_class_index != vhost_user_device_class.index)
+    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
+
+  if (sock_filename == NULL || !(strlen (sock_filename) > 0))
+    return VNET_API_ERROR_INVALID_ARGUMENT;
+
+  vui = vec_elt_at_index (vum->vhost_user_interfaces, hwif->dev_instance);
+
+  /*
+   * Disallow changing the interface to have the same path name
+   * as other interface
+   */
+  if_index = mhash_get (&vum->if_index_by_sock_name, (void *) sock_filename);
+  if (if_index && (*if_index != vui->if_index))
+    return VNET_API_ERROR_IF_ALREADY_EXISTS;
+
+  // First try to open server socket
+  if (is_server)
+    if ((rv = vhost_user_init_server_sock (sock_filename,
+					   &server_sock_fd)) != 0)
+      return rv;
+
+  vhost_user_term_if (vui);
+  vhost_user_vui_init (vnm, vui, server_sock_fd,
+		       sock_filename, feature_mask, &sw_if_idx);
+
+  if (renumber)
+    vnet_interface_name_renumber (sw_if_idx, custom_dev_instance);
+
+  // Process node must connect
+  vlib_process_signal_event (vm, vhost_user_process_node.index, 0, 0);
+
+  return rv;
+}
+
+clib_error_t *
+vhost_user_connect_command_fn (vlib_main_t * vm,
+			       unformat_input_t * input,
+			       vlib_cli_command_t * cmd)
+{
+  unformat_input_t _line_input, *line_input = &_line_input;
+  u8 *sock_filename = NULL;
+  u32 sw_if_index;
+  u8 is_server = 0;
+  u64 feature_mask = (u64) ~ (0ULL);
+  u8 renumber = 0;
+  u32 custom_dev_instance = ~0;
+  u8 hwaddr[6];
+  u8 *hw = NULL;
+  clib_error_t *error = NULL;
+
+  /* Get a line of input. */
+  if (!unformat_user (input, unformat_line_input, line_input))
+    return 0;
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "socket %s", &sock_filename))
+	;
+      else if (unformat (line_input, "server"))
+	is_server = 1;
+      else if (unformat (line_input, "feature-mask 0x%llx", &feature_mask))
+	;
+      else
+	if (unformat
+	    (line_input, "hwaddr %U", unformat_ethernet_address, hwaddr))
+	hw = hwaddr;
+      else if (unformat (line_input, "renumber %d", &custom_dev_instance))
+	{
+	  renumber = 1;
+	}
+      else
+	{
+	  error = clib_error_return (0, "unknown input `%U'",
+				     format_unformat_error, line_input);
+	  goto done;
+	}
+    }
+
+  vnet_main_t *vnm = vnet_get_main ();
+
+  int rv;
+  if ((rv = vhost_user_create_if (vnm, vm, (char *) sock_filename,
+				  is_server, &sw_if_index, feature_mask,
+				  renumber, custom_dev_instance, hw)))
+    {
+      error = clib_error_return (0, "vhost_user_create_if returned %d", rv);
+      goto done;
+    }
+
+  vlib_cli_output (vm, "%U\n", format_vnet_sw_if_index_name, vnet_get_main (),
+		   sw_if_index);
+
+done:
+  vec_free (sock_filename);
+  unformat_free (line_input);
+
+  return error;
+}
+
+clib_error_t *
+vhost_user_delete_command_fn (vlib_main_t * vm,
+			      unformat_input_t * input,
+			      vlib_cli_command_t * cmd)
+{
+  unformat_input_t _line_input, *line_input = &_line_input;
+  u32 sw_if_index = ~0;
+  vnet_main_t *vnm = vnet_get_main ();
+  clib_error_t *error = NULL;
+
+  /* Get a line of input. */
+  if (!unformat_user (input, unformat_line_input, line_input))
+    return 0;
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "sw_if_index %d", &sw_if_index))
+	;
+      else if (unformat
+	       (line_input, "%U", unformat_vnet_sw_interface, vnm,
+		&sw_if_index))
+	{
+	  vnet_hw_interface_t *hwif =
+	    vnet_get_sup_hw_interface (vnm, sw_if_index);
+	  if (hwif == NULL ||
+	      vhost_user_device_class.index != hwif->dev_class_index)
+	    {
+	      error = clib_error_return (0, "Not a vhost interface");
+	      goto done;
+	    }
+	}
+      else
+	{
+	  error = clib_error_return (0, "unknown input `%U'",
+				     format_unformat_error, line_input);
+	  goto done;
+	}
+    }
+
+  vhost_user_delete_if (vnm, vm, sw_if_index);
+
+done:
+  unformat_free (line_input);
+
+  return error;
+}
+
+int
+vhost_user_dump_ifs (vnet_main_t * vnm, vlib_main_t * vm,
+		     vhost_user_intf_details_t ** out_vuids)
+{
+  int rv = 0;
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui;
+  vhost_user_intf_details_t *r_vuids = NULL;
+  vhost_user_intf_details_t *vuid = NULL;
+  u32 *hw_if_indices = 0;
+  vnet_hw_interface_t *hi;
+  u8 *s = NULL;
+  int i;
+
+  if (!out_vuids)
+    return -1;
+
+  pool_foreach (vui, vum->vhost_user_interfaces,
+		vec_add1 (hw_if_indices, vui->hw_if_index);
+    );
+
+  for (i = 0; i < vec_len (hw_if_indices); i++)
+    {
+      hi = vnet_get_hw_interface (vnm, hw_if_indices[i]);
+      vui = pool_elt_at_index (vum->vhost_user_interfaces, hi->dev_instance);
+
+      vec_add2 (r_vuids, vuid, 1);
+      vuid->sw_if_index = vui->sw_if_index;
+      vuid->virtio_net_hdr_sz = vui->virtio_net_hdr_sz;
+      vuid->features = vui->features;
+      vuid->num_regions = vui->nregions;
+      vuid->is_server = vui->unix_server_index != ~0;
+      vuid->sock_errno = vui->sock_errno;
+      strncpy ((char *) vuid->sock_filename, (char *) vui->sock_filename,
+	       sizeof (vuid->sock_filename));
+      vuid->sock_filename[ARRAY_LEN (vuid->sock_filename) - 1] = '\0';
+      s = format (s, "%v%c", hi->name, 0);
+
+      strncpy ((char *) vuid->if_name, (char *) s,
+	       ARRAY_LEN (vuid->if_name) - 1);
+      _vec_len (s) = 0;
+    }
+
+  vec_free (s);
+  vec_free (hw_if_indices);
+
+  *out_vuids = r_vuids;
+
+  return rv;
+}
+
+clib_error_t *
+show_vhost_user_command_fn (vlib_main_t * vm,
+			    unformat_input_t * input,
+			    vlib_cli_command_t * cmd)
+{
+  clib_error_t *error = 0;
+  vnet_main_t *vnm = vnet_get_main ();
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui;
+  u32 hw_if_index, *hw_if_indices = 0;
+  vnet_hw_interface_t *hi;
+  u16 *queue;
+  u32 ci;
+  int i, j, q;
+  int show_descr = 0;
+  struct feat_struct
+  {
+    u8 bit;
+    char *str;
+  };
+  struct feat_struct *feat_entry;
+
+  static struct feat_struct feat_array[] = {
+#define _(s,b) { .str = #s, .bit = b, },
+    foreach_virtio_net_feature
+#undef _
+    {.str = NULL}
+  };
+
+#define foreach_protocol_feature \
+  _(VHOST_USER_PROTOCOL_F_MQ) \
+  _(VHOST_USER_PROTOCOL_F_LOG_SHMFD)
+
+  static struct feat_struct proto_feat_array[] = {
+#define _(s) { .str = #s, .bit = s},
+    foreach_protocol_feature
+#undef _
+    {.str = NULL}
+  };
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat
+	  (input, "%U", unformat_vnet_hw_interface, vnm, &hw_if_index))
+	{
+	  hi = vnet_get_hw_interface (vnm, hw_if_index);
+	  if (vhost_user_device_class.index != hi->dev_class_index)
+	    {
+	      error = clib_error_return (0, "unknown input `%U'",
+					 format_unformat_error, input);
+	      goto done;
+	    }
+	  vec_add1 (hw_if_indices, hw_if_index);
+	}
+      else if (unformat (input, "descriptors") || unformat (input, "desc"))
+	show_descr = 1;
+      else
+	{
+	  error = clib_error_return (0, "unknown input `%U'",
+				     format_unformat_error, input);
+	  goto done;
+	}
+    }
+  if (vec_len (hw_if_indices) == 0)
+    {
+      pool_foreach (vui, vum->vhost_user_interfaces,
+		    vec_add1 (hw_if_indices, vui->hw_if_index);
+	);
+    }
+  vlib_cli_output (vm, "Virtio vhost-user interfaces");
+  vlib_cli_output (vm, "Global:\n  coalesce frames %d time %e",
+		   vum->coalesce_frames, vum->coalesce_time);
+  vlib_cli_output (vm, "  number of rx virtqueues in interrupt mode: %d",
+		   vum->ifq_count);
+
+  for (i = 0; i < vec_len (hw_if_indices); i++)
+    {
+      hi = vnet_get_hw_interface (vnm, hw_if_indices[i]);
+      vui = pool_elt_at_index (vum->vhost_user_interfaces, hi->dev_instance);
+      vlib_cli_output (vm, "Interface: %s (ifindex %d)",
+		       hi->name, hw_if_indices[i]);
+
+      vlib_cli_output (vm, "virtio_net_hdr_sz %d\n"
+		       " features mask (0x%llx): \n"
+		       " features (0x%llx): \n",
+		       vui->virtio_net_hdr_sz, vui->feature_mask,
+		       vui->features);
+
+      feat_entry = (struct feat_struct *) &feat_array;
+      while (feat_entry->str)
+	{
+	  if (vui->features & (1ULL << feat_entry->bit))
+	    vlib_cli_output (vm, "   %s (%d)", feat_entry->str,
+			     feat_entry->bit);
+	  feat_entry++;
+	}
+
+      vlib_cli_output (vm, "  protocol features (0x%llx)",
+		       vui->protocol_features);
+      feat_entry = (struct feat_struct *) &proto_feat_array;
+      while (feat_entry->str)
+	{
+	  if (vui->protocol_features & (1ULL << feat_entry->bit))
+	    vlib_cli_output (vm, "   %s (%d)", feat_entry->str,
+			     feat_entry->bit);
+	  feat_entry++;
+	}
+
+      vlib_cli_output (vm, "\n");
+
+      vlib_cli_output (vm, " socket filename %s type %s errno \"%s\"\n\n",
+		       vui->sock_filename,
+		       (vui->unix_server_index != ~0) ? "server" : "client",
+		       strerror (vui->sock_errno));
+
+      vlib_cli_output (vm, " rx placement: ");
+
+      vec_foreach (queue, vui->rx_queues)
+      {
+	vnet_main_t *vnm = vnet_get_main ();
+	uword thread_index;
+	vnet_hw_interface_rx_mode mode;
+
+	thread_index = vnet_get_device_input_thread_index (vnm,
+							   vui->hw_if_index,
+							   *queue);
+	vnet_hw_interface_get_rx_mode (vnm, vui->hw_if_index, *queue, &mode);
+	vlib_cli_output (vm, "   thread %d on vring %d, %U\n",
+			 thread_index, VHOST_VRING_IDX_TX (*queue),
+			 format_vnet_hw_interface_rx_mode, mode);
+      }
+
+      vlib_cli_output (vm, " tx placement: %s\n",
+		       vui->use_tx_spinlock ? "spin-lock" : "lock-free");
+
+      vec_foreach_index (ci, vui->per_cpu_tx_qid)
+      {
+	vlib_cli_output (vm, "   thread %d on vring %d\n", ci,
+			 VHOST_VRING_IDX_RX (vui->per_cpu_tx_qid[ci]));
+      }
+
+      vlib_cli_output (vm, "\n");
+
+      vlib_cli_output (vm, " Memory regions (total %d)\n", vui->nregions);
+
+      if (vui->nregions)
+	{
+	  vlib_cli_output (vm,
+			   " region fd    guest_phys_addr    memory_size        userspace_addr     mmap_offset        mmap_addr\n");
+	  vlib_cli_output (vm,
+			   " ====== ===== ================== ================== ================== ================== ==================\n");
+	}
+      for (j = 0; j < vui->nregions; j++)
+	{
+	  vlib_cli_output (vm,
+			   "  %d     %-5d 0x%016lx 0x%016lx 0x%016lx 0x%016lx 0x%016lx\n",
+			   j, vui->region_mmap_fd[j],
+			   vui->regions[j].guest_phys_addr,
+			   vui->regions[j].memory_size,
+			   vui->regions[j].userspace_addr,
+			   vui->regions[j].mmap_offset,
+			   pointer_to_uword (vui->region_mmap_addr[j]));
+	}
+      for (q = 0; q < VHOST_VRING_MAX_N; q++)
+	{
+	  if (!vui->vrings[q].started)
+	    continue;
+
+	  vlib_cli_output (vm, "\n Virtqueue %d (%s%s)\n", q,
+			   (q & 1) ? "RX" : "TX",
+			   vui->vrings[q].enabled ? "" : " disabled");
+
+	  vlib_cli_output (vm,
+			   "  qsz %d last_avail_idx %d last_used_idx %d\n",
+			   vui->vrings[q].qsz_mask + 1,
+			   vui->vrings[q].last_avail_idx,
+			   vui->vrings[q].last_used_idx);
+
+	  if (vui->vrings[q].avail && vui->vrings[q].used)
+	    vlib_cli_output (vm,
+			     "  avail.flags %x avail.idx %d used.flags %x used.idx %d\n",
+			     vui->vrings[q].avail->flags,
+			     vui->vrings[q].avail->idx,
+			     vui->vrings[q].used->flags,
+			     vui->vrings[q].used->idx);
+
+	  int kickfd = UNIX_GET_FD (vui->vrings[q].kickfd_idx);
+	  int callfd = UNIX_GET_FD (vui->vrings[q].callfd_idx);
+	  vlib_cli_output (vm, "  kickfd %d callfd %d errfd %d\n",
+			   kickfd, callfd, vui->vrings[q].errfd);
+
+	  if (show_descr)
+	    {
+	      vlib_cli_output (vm, "\n  descriptor table:\n");
+	      vlib_cli_output (vm,
+			       "   id          addr         len  flags  next      user_addr\n");
+	      vlib_cli_output (vm,
+			       "  ===== ================== ===== ====== ===== ==================\n");
+	      for (j = 0; j < vui->vrings[q].qsz_mask + 1; j++)
+		{
+		  u32 mem_hint = 0;
+		  vlib_cli_output (vm,
+				   "  %-5d 0x%016lx %-5d 0x%04x %-5d 0x%016lx\n",
+				   j, vui->vrings[q].desc[j].addr,
+				   vui->vrings[q].desc[j].len,
+				   vui->vrings[q].desc[j].flags,
+				   vui->vrings[q].desc[j].next,
+				   pointer_to_uword (map_guest_mem
+						     (vui,
+						      vui->vrings[q].desc[j].
+						      addr, &mem_hint)));
+		}
+	    }
+	}
+      vlib_cli_output (vm, "\n");
+    }
+done:
+  vec_free (hw_if_indices);
+  return error;
+}
+
+/*
+ * CLI functions
+ */
+
+/*?
+ * Create a vHost User interface. Once created, a new virtual interface
+ * will exist with the name '<em>VirtualEthernet0/0/x</em>', where '<em>x</em>'
+ * is the next free index.
+ *
+ * There are several parameters associated with a vHost interface:
+ *
+ * - <b>socket <socket-filename></b> - Name of the linux socket used by hypervisor
+ * and VPP to manage the vHost interface. If in '<em>server</em>' mode, VPP will
+ * create the socket if it does not already exist. If in '<em>client</em>' mode,
+ * hypervisor will create the socket if it does not already exist. The VPP code
+ * is indifferent to the file location. However, if SELinux is enabled, then the
+ * socket needs to be created in '<em>/var/run/vpp/</em>'.
+ *
+ * - <b>server</b> - Optional flag to indicate that VPP should be the server for
+ * the linux socket. If not provided, VPP will be the client. In '<em>server</em>'
+ *  mode, the VM can be reset without tearing down the vHost Interface. In
+ * '<em>client</em>' mode, VPP can be reset without bringing down the VM and
+ * tearing down the vHost Interface.
+ *
+ * - <b>feature-mask <hex></b> - Optional virtio/vhost feature set negotiated at
+ * startup. <b>This is intended for degugging only.</b> It is recommended that this
+ * parameter not be used except by experienced users. By default, all supported
+ * features will be advertised. Otherwise, provide the set of features desired.
+ *   - 0x000008000 (15) - VIRTIO_NET_F_MRG_RXBUF
+ *   - 0x000020000 (17) - VIRTIO_NET_F_CTRL_VQ
+ *   - 0x000200000 (21) - VIRTIO_NET_F_GUEST_ANNOUNCE
+ *   - 0x000400000 (22) - VIRTIO_NET_F_MQ
+ *   - 0x004000000 (26) - VHOST_F_LOG_ALL
+ *   - 0x008000000 (27) - VIRTIO_F_ANY_LAYOUT
+ *   - 0x010000000 (28) - VIRTIO_F_INDIRECT_DESC
+ *   - 0x040000000 (30) - VHOST_USER_F_PROTOCOL_FEATURES
+ *   - 0x100000000 (32) - VIRTIO_F_VERSION_1
+ *
+ * - <b>hwaddr <mac-addr></b> - Optional ethernet address, can be in either
+ * X:X:X:X:X:X unix or X.X.X cisco format.
+ *
+ * - <b>renumber <dev_instance></b> - Optional parameter which allows the instance
+ * in the name to be specified. If instance already exists, name will be used
+ * anyway and multiple instances will have the same name. Use with caution.
+ *
+ * @cliexpar
+ * Example of how to create a vhost interface with VPP as the client and all features enabled:
+ * @cliexstart{create vhost-user socket /var/run/vpp/vhost1.sock}
+ * VirtualEthernet0/0/0
+ * @cliexend
+ * Example of how to create a vhost interface with VPP as the server and with just
+ * multiple queues enabled:
+ * @cliexstart{create vhost-user socket /var/run/vpp/vhost2.sock server feature-mask 0x40400000}
+ * VirtualEthernet0/0/1
+ * @cliexend
+ * Once the vHost interface is created, enable the interface using:
+ * @cliexcmd{set interface state VirtualEthernet0/0/0 up}
+?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (vhost_user_connect_command, static) = {
+    .path = "create vhost-user",
+    .short_help = "create vhost-user socket <socket-filename> [server] "
+    "[feature-mask <hex>] [hwaddr <mac-addr>] [renumber <dev_instance>] ",
+    .function = vhost_user_connect_command_fn,
+};
+/* *INDENT-ON* */
+
+/*?
+ * Delete a vHost User interface using the interface name or the
+ * software interface index. Use the '<em>show interface</em>'
+ * command to determine the software interface index. On deletion,
+ * the linux socket will not be deleted.
+ *
+ * @cliexpar
+ * Example of how to delete a vhost interface by name:
+ * @cliexcmd{delete vhost-user VirtualEthernet0/0/1}
+ * Example of how to delete a vhost interface by software interface index:
+ * @cliexcmd{delete vhost-user sw_if_index 1}
+?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (vhost_user_delete_command, static) = {
+    .path = "delete vhost-user",
+    .short_help = "delete vhost-user {<interface> | sw_if_index <sw_idx>}",
+    .function = vhost_user_delete_command_fn,
+};
+
+/*?
+ * Display the attributes of a single vHost User interface (provide interface
+ * name), multiple vHost User interfaces (provide a list of interface names seperated
+ * by spaces) or all Vhost User interfaces (omit an interface name to display all
+ * vHost interfaces).
+ *
+ * @cliexpar
+ * @parblock
+ * Example of how to display a vhost interface:
+ * @cliexstart{show vhost-user VirtualEthernet0/0/0}
+ * Virtio vhost-user interfaces
+ * Global:
+ *   coalesce frames 32 time 1e-3
+ * Interface: VirtualEthernet0/0/0 (ifindex 1)
+ * virtio_net_hdr_sz 12
+ *  features mask (0xffffffffffffffff):
+ *  features (0x50408000):
+ *    VIRTIO_NET_F_MRG_RXBUF (15)
+ *    VIRTIO_NET_F_MQ (22)
+ *    VIRTIO_F_INDIRECT_DESC (28)
+ *    VHOST_USER_F_PROTOCOL_FEATURES (30)
+ *   protocol features (0x3)
+ *    VHOST_USER_PROTOCOL_F_MQ (0)
+ *    VHOST_USER_PROTOCOL_F_LOG_SHMFD (1)
+ *
+ *  socket filename /var/run/vpp/vhost1.sock type client errno "Success"
+ *
+ * rx placement:
+ *    thread 1 on vring 1
+ *    thread 1 on vring 5
+ *    thread 2 on vring 3
+ *    thread 2 on vring 7
+ *  tx placement: spin-lock
+ *    thread 0 on vring 0
+ *    thread 1 on vring 2
+ *    thread 2 on vring 0
+ *
+ * Memory regions (total 2)
+ * region fd    guest_phys_addr    memory_size        userspace_addr     mmap_offset        mmap_addr
+ * ====== ===== ================== ================== ================== ================== ==================
+ *   0     60    0x0000000000000000 0x00000000000a0000 0x00002aaaaac00000 0x0000000000000000 0x00002aab2b400000
+ *   1     61    0x00000000000c0000 0x000000003ff40000 0x00002aaaaacc0000 0x00000000000c0000 0x00002aababcc0000
+ *
+ *  Virtqueue 0 (TX)
+ *   qsz 256 last_avail_idx 0 last_used_idx 0
+ *   avail.flags 1 avail.idx 128 used.flags 1 used.idx 0
+ *   kickfd 62 callfd 64 errfd -1
+ *
+ *  Virtqueue 1 (RX)
+ *   qsz 256 last_avail_idx 0 last_used_idx 0
+ *   avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
+ *   kickfd 65 callfd 66 errfd -1
+ *
+ *  Virtqueue 2 (TX)
+ *   qsz 256 last_avail_idx 0 last_used_idx 0
+ *   avail.flags 1 avail.idx 128 used.flags 1 used.idx 0
+ *   kickfd 63 callfd 70 errfd -1
+ *
+ *  Virtqueue 3 (RX)
+ *   qsz 256 last_avail_idx 0 last_used_idx 0
+ *   avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
+ *   kickfd 72 callfd 74 errfd -1
+ *
+ *  Virtqueue 4 (TX disabled)
+ *   qsz 256 last_avail_idx 0 last_used_idx 0
+ *   avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
+ *   kickfd 76 callfd 78 errfd -1
+ *
+ *  Virtqueue 5 (RX disabled)
+ *   qsz 256 last_avail_idx 0 last_used_idx 0
+ *   avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
+ *   kickfd 80 callfd 82 errfd -1
+ *
+ *  Virtqueue 6 (TX disabled)
+ *   qsz 256 last_avail_idx 0 last_used_idx 0
+ *  avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
+ *   kickfd 84 callfd 86 errfd -1
+ *
+ *  Virtqueue 7 (RX disabled)
+ *   qsz 256 last_avail_idx 0 last_used_idx 0
+ *   avail.flags 1 avail.idx 0 used.flags 1 used.idx 0
+ *   kickfd 88 callfd 90 errfd -1
+ *
+ * @cliexend
+ *
+ * The optional '<em>descriptors</em>' parameter will display the same output as
+ * the previous example but will include the descriptor table for each queue.
+ * The output is truncated below:
+ * @cliexstart{show vhost-user VirtualEthernet0/0/0 descriptors}
+ * Virtio vhost-user interfaces
+ * Global:
+ *   coalesce frames 32 time 1e-3
+ * Interface: VirtualEthernet0/0/0 (ifindex 1)
+ * virtio_net_hdr_sz 12
+ *  features mask (0xffffffffffffffff):
+ *  features (0x50408000):
+ *    VIRTIO_NET_F_MRG_RXBUF (15)
+ *    VIRTIO_NET_F_MQ (22)
+ * :
+ *  Virtqueue 0 (TX)
+ *   qsz 256 last_avail_idx 0 last_used_idx 0
+ *   avail.flags 1 avail.idx 128 used.flags 1 used.idx 0
+ *   kickfd 62 callfd 64 errfd -1
+ *
+ *   descriptor table:
+ *    id          addr         len  flags  next      user_addr
+ *   ===== ================== ===== ====== ===== ==================
+ *   0     0x0000000010b6e974 2060  0x0002 1     0x00002aabbc76e974
+ *   1     0x0000000010b6e034 2060  0x0002 2     0x00002aabbc76e034
+ *   2     0x0000000010b6d6f4 2060  0x0002 3     0x00002aabbc76d6f4
+ *   3     0x0000000010b6cdb4 2060  0x0002 4     0x00002aabbc76cdb4
+ *   4     0x0000000010b6c474 2060  0x0002 5     0x00002aabbc76c474
+ *   5     0x0000000010b6bb34 2060  0x0002 6     0x00002aabbc76bb34
+ *   6     0x0000000010b6b1f4 2060  0x0002 7     0x00002aabbc76b1f4
+ *   7     0x0000000010b6a8b4 2060  0x0002 8     0x00002aabbc76a8b4
+ *   8     0x0000000010b69f74 2060  0x0002 9     0x00002aabbc769f74
+ *   9     0x0000000010b69634 2060  0x0002 10    0x00002aabbc769634
+ *   10    0x0000000010b68cf4 2060  0x0002 11    0x00002aabbc768cf4
+ * :
+ *   249   0x0000000000000000 0     0x0000 250   0x00002aab2b400000
+ *   250   0x0000000000000000 0     0x0000 251   0x00002aab2b400000
+ *   251   0x0000000000000000 0     0x0000 252   0x00002aab2b400000
+ *   252   0x0000000000000000 0     0x0000 253   0x00002aab2b400000
+ *   253   0x0000000000000000 0     0x0000 254   0x00002aab2b400000
+ *   254   0x0000000000000000 0     0x0000 255   0x00002aab2b400000
+ *   255   0x0000000000000000 0     0x0000 32768 0x00002aab2b400000
+ *
+ *  Virtqueue 1 (RX)
+ *   qsz 256 last_avail_idx 0 last_used_idx 0
+ * :
+ * @cliexend
+ * @endparblock
+?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (show_vhost_user_command, static) = {
+    .path = "show vhost-user",
+    .short_help = "show vhost-user [<interface> [<interface> [..]]] [descriptors]",
+    .function = show_vhost_user_command_fn,
+};
+/* *INDENT-ON* */
+
+clib_error_t *
+debug_vhost_user_command_fn (vlib_main_t * vm,
+			     unformat_input_t * input,
+			     vlib_cli_command_t * cmd)
+{
+  unformat_input_t _line_input, *line_input = &_line_input;
+  clib_error_t *error = NULL;
+  vhost_user_main_t *vum = &vhost_user_main;
+  u8 onoff = 0;
+  u8 input_found = 0;
+
+  /* Get a line of input. */
+  if (!unformat_user (input, unformat_line_input, line_input))
+    return clib_error_return (0, "missing argument");
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (input_found)
+	{
+	  error = clib_error_return (0, "unknown input `%U'",
+				     format_unformat_error, line_input);
+	  goto done;
+	}
+
+      if (unformat (line_input, "on"))
+	{
+	  input_found = 1;
+	  onoff = 1;
+	}
+      else if (unformat (line_input, "off"))
+	{
+	  input_found = 1;
+	  onoff = 0;
+	}
+      else
+	{
+	  error = clib_error_return (0, "unknown input `%U'",
+				     format_unformat_error, line_input);
+	  goto done;
+	}
+    }
+
+  vum->debug = onoff;
+
+done:
+  unformat_free (line_input);
+
+  return error;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (debug_vhost_user_command, static) = {
+    .path = "debug vhost-user",
+    .short_help = "debug vhost-user <on | off>",
+    .function = debug_vhost_user_command_fn,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+vhost_user_config (vlib_main_t * vm, unformat_input_t * input)
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "coalesce-frames %d", &vum->coalesce_frames))
+	;
+      else if (unformat (input, "coalesce-time %f", &vum->coalesce_time))
+	;
+      else if (unformat (input, "dont-dump-memory"))
+	vum->dont_dump_vhost_user_memory = 1;
+      else
+	return clib_error_return (0, "unknown input `%U'",
+				  format_unformat_error, input);
+    }
+
+  return 0;
+}
+
+
+/* vhost-user { ... } configuration. */
+VLIB_CONFIG_FUNCTION (vhost_user_config, "vhost-user");
+
+void
+vhost_user_unmap_all (void)
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui;
+
+  if (vum->dont_dump_vhost_user_memory)
+    {
+      pool_foreach (vui, vum->vhost_user_interfaces,
+		    unmap_all_mem_regions (vui);
+	);
+    }
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/devices/virtio/vhost-user.h b/src/vnet/devices/virtio/vhost_user.h
similarity index 87%
rename from src/vnet/devices/virtio/vhost-user.h
rename to src/vnet/devices/virtio/vhost_user.h
index 105b92b..ff06695 100644
--- a/src/vnet/devices/virtio/vhost-user.h
+++ b/src/vnet/devices/virtio/vhost_user.h
@@ -45,6 +45,40 @@
 #define VRING_USED_F_NO_NOTIFY  1
 #define VRING_AVAIL_F_NO_INTERRUPT 1
 
+#define DBG_SOCK(args...)                       \
+  {                                             \
+    vhost_user_main_t *_vum = &vhost_user_main; \
+    if (_vum->debug)                            \
+      clib_warning(args);                       \
+  };
+
+#define VHOST_DEBUG_VQ 0
+
+#if VHOST_DEBUG_VQ == 1
+#define DBG_VQ(args...) clib_warning(args);
+#else
+#define DBG_VQ(args...)
+#endif
+
+#define UNIX_GET_FD(unixfd_idx) ({ \
+    typeof(unixfd_idx) __unixfd_idx = (unixfd_idx); \
+    (__unixfd_idx != ~0) ? \
+        pool_elt_at_index (file_main.file_pool, \
+                           __unixfd_idx)->file_descriptor : -1; })
+
+#define foreach_virtio_trace_flags \
+  _ (SIMPLE_CHAINED, 0, "Simple descriptor chaining") \
+  _ (SINGLE_DESC,  1, "Single descriptor packet") \
+  _ (INDIRECT, 2, "Indirect descriptor") \
+  _ (MAP_ERROR, 4, "Memory mapping error")
+
+typedef enum
+{
+#define _(n,i,s) VIRTIO_TRACE_F_##n,
+  foreach_virtio_trace_flags
+#undef _
+} virtio_trace_flag_t;
+
 #define foreach_virtio_net_feature      \
  _ (VIRTIO_NET_F_MRG_RXBUF, 15)         \
  _ (VIRTIO_NET_F_CTRL_VQ, 17)           \
@@ -56,7 +90,6 @@
  _ (VHOST_USER_F_PROTOCOL_FEATURES, 30) \
  _ (VIRTIO_F_VERSION_1, 32)
 
-
 typedef enum
 {
 #define _(f,n) FEAT_##f = (n),
@@ -331,6 +364,11 @@
 int vhost_user_dump_ifs (vnet_main_t * vnm, vlib_main_t * vm,
 			 vhost_user_intf_details_t ** out_vuids);
 
+extern vlib_node_registration_t vhost_user_send_interrupt_node;
+extern vnet_device_class_t vhost_user_device_class;
+extern vlib_node_registration_t vhost_user_input_node;
+extern vhost_user_main_t vhost_user_main;
+
 #endif
 
 /*
diff --git a/src/vnet/devices/virtio/vhost_user_api.c b/src/vnet/devices/virtio/vhost_user_api.c
index 442d914..59dba25 100644
--- a/src/vnet/devices/virtio/vhost_user_api.c
+++ b/src/vnet/devices/virtio/vhost_user_api.c
@@ -22,7 +22,7 @@
 
 #include <vnet/interface.h>
 #include <vnet/api_errno.h>
-#include <vnet/devices/virtio/vhost-user.h>
+#include <vnet/devices/virtio/vhost_user.h>
 
 #include <vnet/vnet_msg_enum.h>
 
diff --git a/src/vnet/devices/virtio/vhost_user_inline.h b/src/vnet/devices/virtio/vhost_user_inline.h
new file mode 100644
index 0000000..9f61351
--- /dev/null
+++ b/src/vnet/devices/virtio/vhost_user_inline.h
@@ -0,0 +1,262 @@
+/*
+ * Copyright (c) 2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef __VIRTIO_VHOST_USER_INLINE_H__
+#define __VIRTIO_VHOST_USER_INLINE_H__
+/* vhost-user inline functions */
+
+static_always_inline void *
+map_guest_mem (vhost_user_intf_t * vui, uword addr, u32 * hint)
+{
+  int i = *hint;
+  if (PREDICT_TRUE ((vui->regions[i].guest_phys_addr <= addr) &&
+		    ((vui->regions[i].guest_phys_addr +
+		      vui->regions[i].memory_size) > addr)))
+    {
+      return (void *) (vui->region_mmap_addr[i] + addr -
+		       vui->regions[i].guest_phys_addr);
+    }
+#if __SSE4_2__
+  __m128i rl, rh, al, ah, r;
+  al = _mm_set1_epi64x (addr + 1);
+  ah = _mm_set1_epi64x (addr);
+
+  rl = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_lo[0]);
+  rl = _mm_cmpgt_epi64 (al, rl);
+  rh = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_hi[0]);
+  rh = _mm_cmpgt_epi64 (rh, ah);
+  r = _mm_and_si128 (rl, rh);
+
+  rl = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_lo[2]);
+  rl = _mm_cmpgt_epi64 (al, rl);
+  rh = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_hi[2]);
+  rh = _mm_cmpgt_epi64 (rh, ah);
+  r = _mm_blend_epi16 (r, _mm_and_si128 (rl, rh), 0x22);
+
+  rl = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_lo[4]);
+  rl = _mm_cmpgt_epi64 (al, rl);
+  rh = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_hi[4]);
+  rh = _mm_cmpgt_epi64 (rh, ah);
+  r = _mm_blend_epi16 (r, _mm_and_si128 (rl, rh), 0x44);
+
+  rl = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_lo[6]);
+  rl = _mm_cmpgt_epi64 (al, rl);
+  rh = _mm_loadu_si128 ((__m128i *) & vui->region_guest_addr_hi[6]);
+  rh = _mm_cmpgt_epi64 (rh, ah);
+  r = _mm_blend_epi16 (r, _mm_and_si128 (rl, rh), 0x88);
+
+  r = _mm_shuffle_epi8 (r, _mm_set_epi64x (0, 0x0e060c040a020800));
+  i = count_trailing_zeros (_mm_movemask_epi8 (r) |
+			    (1 << VHOST_MEMORY_MAX_NREGIONS));
+
+  if (i < vui->nregions)
+    {
+      *hint = i;
+      return (void *) (vui->region_mmap_addr[i] + addr -
+		       vui->regions[i].guest_phys_addr);
+    }
+#elif __aarch64__ && __ARM_NEON
+  uint64x2_t al, ah, rl, rh, r;
+  uint32_t u32 = 0;
+
+  al = vdupq_n_u64 (addr + 1);
+  ah = vdupq_n_u64 (addr);
+
+  /*First Iteration */
+  rl = vld1q_u64 (&vui->region_guest_addr_lo[0]);
+  rl = vcgtq_u64 (al, rl);
+  rh = vld1q_u64 (&vui->region_guest_addr_hi[0]);
+  rh = vcgtq_u64 (rh, ah);
+  r = vandq_u64 (rl, rh);
+  u32 |= (vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 0) & 0x1);
+  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 8) & 0x1) << 1);
+
+  if (u32)
+    {
+      i = count_trailing_zeros (u32);
+      goto vhost_map_guest_mem_done;
+    }
+
+  /*Second Iteration */
+  rl = vld1q_u64 (&vui->region_guest_addr_lo[2]);
+  rl = vcgtq_u64 (al, rl);
+  rh = vld1q_u64 (&vui->region_guest_addr_hi[2]);
+  rh = vcgtq_u64 (rh, ah);
+  r = vandq_u64 (rl, rh);
+  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 0) & 0x1) << 2);
+  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 8) & 0x1) << 3);
+
+  if (u32)
+    {
+      i = count_trailing_zeros (u32);
+      goto vhost_map_guest_mem_done;
+    }
+
+  /*Third Iteration */
+  rl = vld1q_u64 (&vui->region_guest_addr_lo[4]);
+  rl = vcgtq_u64 (al, rl);
+  rh = vld1q_u64 (&vui->region_guest_addr_hi[4]);
+  rh = vcgtq_u64 (rh, ah);
+  r = vandq_u64 (rl, rh);
+  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 0) & 0x1) << 6);
+  u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 8) & 0x1) << 7);
+
+  i = count_trailing_zeros (u32 | (1 << VHOST_MEMORY_MAX_NREGIONS));
+
+vhost_map_guest_mem_done:
+  if (i < vui->nregions)
+    {
+      *hint = i;
+      return (void *) (vui->region_mmap_addr[i] + addr -
+		       vui->regions[i].guest_phys_addr);
+    }
+#else
+  for (i = 0; i < vui->nregions; i++)
+    {
+      if ((vui->regions[i].guest_phys_addr <= addr) &&
+	  ((vui->regions[i].guest_phys_addr + vui->regions[i].memory_size) >
+	   addr))
+	{
+	  *hint = i;
+	  return (void *) (vui->region_mmap_addr[i] + addr -
+			   vui->regions[i].guest_phys_addr);
+	}
+    }
+#endif
+  DBG_VQ ("failed to map guest mem addr %llx", addr);
+  *hint = 0;
+  return 0;
+}
+
+static_always_inline void *
+map_user_mem (vhost_user_intf_t * vui, uword addr)
+{
+  int i;
+  for (i = 0; i < vui->nregions; i++)
+    {
+      if ((vui->regions[i].userspace_addr <= addr) &&
+	  ((vui->regions[i].userspace_addr + vui->regions[i].memory_size) >
+	   addr))
+	{
+	  return (void *) (vui->region_mmap_addr[i] + addr -
+			   vui->regions[i].userspace_addr);
+	}
+    }
+  return 0;
+}
+
+#define VHOST_LOG_PAGE 0x1000
+
+static_always_inline void
+vhost_user_log_dirty_pages_2 (vhost_user_intf_t * vui,
+			      u64 addr, u64 len, u8 is_host_address)
+{
+  if (PREDICT_TRUE (vui->log_base_addr == 0
+		    || !(vui->features & (1 << FEAT_VHOST_F_LOG_ALL))))
+    {
+      return;
+    }
+  if (is_host_address)
+    {
+      addr = pointer_to_uword (map_user_mem (vui, (uword) addr));
+    }
+  if (PREDICT_FALSE ((addr + len - 1) / VHOST_LOG_PAGE / 8 >= vui->log_size))
+    {
+      DBG_SOCK ("vhost_user_log_dirty_pages(): out of range\n");
+      return;
+    }
+
+  CLIB_MEMORY_BARRIER ();
+  u64 page = addr / VHOST_LOG_PAGE;
+  while (page * VHOST_LOG_PAGE < addr + len)
+    {
+      ((u8 *) vui->log_base_addr)[page / 8] |= 1 << page % 8;
+      page++;
+    }
+}
+
+
+#define vhost_user_log_dirty_ring(vui, vq, member) \
+  if (PREDICT_FALSE(vq->log_used)) { \
+    vhost_user_log_dirty_pages_2(vui, vq->log_guest_addr + STRUCT_OFFSET_OF(vring_used_t, member), \
+                             sizeof(vq->used->member), 0); \
+  }
+
+static_always_inline u8 *
+format_vhost_trace (u8 * s, va_list * va)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *);
+  CLIB_UNUSED (vnet_main_t * vnm) = vnet_get_main ();
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_trace_t *t = va_arg (*va, vhost_trace_t *);
+  vhost_user_intf_t *vui = pool_elt_at_index (vum->vhost_user_interfaces,
+					      t->device_index);
+
+  vnet_sw_interface_t *sw = vnet_get_sw_interface (vnm, vui->sw_if_index);
+
+  u32 indent = format_get_indent (s);
+
+  s = format (s, "%U %U queue %d\n", format_white_space, indent,
+	      format_vnet_sw_interface_name, vnm, sw, t->qid);
+
+  s = format (s, "%U virtio flags:\n", format_white_space, indent);
+#define _(n,i,st) \
+          if (t->virtio_ring_flags & (1 << VIRTIO_TRACE_F_##n)) \
+            s = format (s, "%U  %s %s\n", format_white_space, indent, #n, st);
+  foreach_virtio_trace_flags
+#undef _
+    s = format (s, "%U virtio_net_hdr first_desc_len %u\n",
+		format_white_space, indent, t->first_desc_len);
+
+  s = format (s, "%U   flags 0x%02x gso_type %u\n",
+	      format_white_space, indent,
+	      t->hdr.hdr.flags, t->hdr.hdr.gso_type);
+
+  if (vui->virtio_net_hdr_sz == 12)
+    s = format (s, "%U   num_buff %u",
+		format_white_space, indent, t->hdr.num_buffers);
+
+  return s;
+}
+
+static_always_inline void
+vhost_user_send_call (vlib_main_t * vm, vhost_user_vring_t * vq)
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+  u64 x = 1;
+  int fd = UNIX_GET_FD (vq->callfd_idx);
+  int rv;
+
+  rv = write (fd, &x, sizeof (x));
+  if (rv <= 0)
+    {
+      clib_unix_warning
+	("Error: Could not write to unix socket for callfd %d", fd);
+      return;
+    }
+
+  vq->n_since_last_int = 0;
+  vq->int_deadline = vlib_time_now (vm) + vum->coalesce_time;
+}
+
+#endif
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/devices/virtio/vhost_user_input.c b/src/vnet/devices/virtio/vhost_user_input.c
new file mode 100644
index 0000000..3db4473
--- /dev/null
+++ b/src/vnet/devices/virtio/vhost_user_input.c
@@ -0,0 +1,678 @@
+/*
+ *------------------------------------------------------------------
+ * vhost-user-input
+ *
+ * Copyright (c) 2014-2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+#include <fcntl.h>		/* for open */
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/uio.h>		/* for iovec */
+#include <netinet/in.h>
+#include <sys/vfs.h>
+
+#include <linux/if_arp.h>
+#include <linux/if_tun.h>
+
+#include <vlib/vlib.h>
+#include <vlib/unix/unix.h>
+
+#include <vnet/ip/ip.h>
+
+#include <vnet/ethernet/ethernet.h>
+#include <vnet/devices/devices.h>
+#include <vnet/feature/feature.h>
+
+#include <vnet/devices/virtio/vhost_user.h>
+#include <vnet/devices/virtio/vhost_user_inline.h>
+
+/*
+ * When an RX queue is down but active, received packets
+ * must be discarded. This value controls up to how many
+ * packets will be discarded during each round.
+ */
+#define VHOST_USER_DOWN_DISCARD_COUNT 256
+
+/*
+ * When the number of available buffers gets under this threshold,
+ * RX node will start discarding packets.
+ */
+#define VHOST_USER_RX_BUFFER_STARVATION 32
+
+/*
+ * On the receive side, the host should free descriptors as soon
+ * as possible in order to avoid TX drop in the VM.
+ * This value controls the number of copy operations that are stacked
+ * before copy is done for all and descriptors are given back to
+ * the guest.
+ * The value 64 was obtained by testing (48 and 128 were not as good).
+ */
+#define VHOST_USER_RX_COPY_THRESHOLD 64
+
+vlib_node_registration_t vhost_user_input_node;
+
+#define foreach_vhost_user_input_func_error      \
+  _(NO_ERROR, "no error")  \
+  _(NO_BUFFER, "no available buffer")  \
+  _(MMAP_FAIL, "mmap failure")  \
+  _(INDIRECT_OVERFLOW, "indirect descriptor overflows table")  \
+  _(UNDERSIZED_FRAME, "undersized ethernet frame received (< 14 bytes)") \
+  _(FULL_RX_QUEUE, "full rx queue (possible driver tx drop)")
+
+typedef enum
+{
+#define _(f,s) VHOST_USER_INPUT_FUNC_ERROR_##f,
+  foreach_vhost_user_input_func_error
+#undef _
+    VHOST_USER_INPUT_FUNC_N_ERROR,
+} vhost_user_input_func_error_t;
+
+static __clib_unused char *vhost_user_input_func_error_strings[] = {
+#define _(n,s) s,
+  foreach_vhost_user_input_func_error
+#undef _
+};
+
+static_always_inline void
+vhost_user_rx_trace (vhost_trace_t * t,
+		     vhost_user_intf_t * vui, u16 qid,
+		     vlib_buffer_t * b, vhost_user_vring_t * txvq)
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+  u32 last_avail_idx = txvq->last_avail_idx;
+  u32 desc_current = txvq->avail->ring[last_avail_idx & txvq->qsz_mask];
+  vring_desc_t *hdr_desc = 0;
+  virtio_net_hdr_mrg_rxbuf_t *hdr;
+  u32 hint = 0;
+
+  memset (t, 0, sizeof (*t));
+  t->device_index = vui - vum->vhost_user_interfaces;
+  t->qid = qid;
+
+  hdr_desc = &txvq->desc[desc_current];
+  if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT)
+    {
+      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_INDIRECT;
+      /* Header is the first here */
+      hdr_desc = map_guest_mem (vui, txvq->desc[desc_current].addr, &hint);
+    }
+  if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT)
+    {
+      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_SIMPLE_CHAINED;
+    }
+  if (!(txvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT) &&
+      !(txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT))
+    {
+      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_SINGLE_DESC;
+    }
+
+  t->first_desc_len = hdr_desc ? hdr_desc->len : 0;
+
+  if (!hdr_desc || !(hdr = map_guest_mem (vui, hdr_desc->addr, &hint)))
+    {
+      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_MAP_ERROR;
+    }
+  else
+    {
+      u32 len = vui->virtio_net_hdr_sz;
+      memcpy (&t->hdr, hdr, len > hdr_desc->len ? hdr_desc->len : len);
+    }
+}
+
+static_always_inline u32
+vhost_user_input_copy (vhost_user_intf_t * vui, vhost_copy_t * cpy,
+		       u16 copy_len, u32 * map_hint)
+{
+  void *src0, *src1, *src2, *src3;
+  if (PREDICT_TRUE (copy_len >= 4))
+    {
+      if (PREDICT_FALSE (!(src2 = map_guest_mem (vui, cpy[0].src, map_hint))))
+	return 1;
+      if (PREDICT_FALSE (!(src3 = map_guest_mem (vui, cpy[1].src, map_hint))))
+	return 1;
+
+      while (PREDICT_TRUE (copy_len >= 4))
+	{
+	  src0 = src2;
+	  src1 = src3;
+
+	  if (PREDICT_FALSE
+	      (!(src2 = map_guest_mem (vui, cpy[2].src, map_hint))))
+	    return 1;
+	  if (PREDICT_FALSE
+	      (!(src3 = map_guest_mem (vui, cpy[3].src, map_hint))))
+	    return 1;
+
+	  CLIB_PREFETCH (src2, 64, LOAD);
+	  CLIB_PREFETCH (src3, 64, LOAD);
+
+	  clib_memcpy ((void *) cpy[0].dst, src0, cpy[0].len);
+	  clib_memcpy ((void *) cpy[1].dst, src1, cpy[1].len);
+	  copy_len -= 2;
+	  cpy += 2;
+	}
+    }
+  while (copy_len)
+    {
+      if (PREDICT_FALSE (!(src0 = map_guest_mem (vui, cpy->src, map_hint))))
+	return 1;
+      clib_memcpy ((void *) cpy->dst, src0, cpy->len);
+      copy_len -= 1;
+      cpy += 1;
+    }
+  return 0;
+}
+
+/**
+ * Try to discard packets from the tx ring (VPP RX path).
+ * Returns the number of discarded packets.
+ */
+static_always_inline u32
+vhost_user_rx_discard_packet (vlib_main_t * vm,
+			      vhost_user_intf_t * vui,
+			      vhost_user_vring_t * txvq, u32 discard_max)
+{
+  /*
+   * On the RX side, each packet corresponds to one descriptor
+   * (it is the same whether it is a shallow descriptor, chained, or indirect).
+   * Therefore, discarding a packet is like discarding a descriptor.
+   */
+  u32 discarded_packets = 0;
+  u32 avail_idx = txvq->avail->idx;
+  while (discarded_packets != discard_max)
+    {
+      if (avail_idx == txvq->last_avail_idx)
+	goto out;
+
+      u16 desc_chain_head =
+	txvq->avail->ring[txvq->last_avail_idx & txvq->qsz_mask];
+      txvq->last_avail_idx++;
+      txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].id =
+	desc_chain_head;
+      txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].len = 0;
+      vhost_user_log_dirty_ring (vui, txvq,
+				 ring[txvq->last_used_idx & txvq->qsz_mask]);
+      txvq->last_used_idx++;
+      discarded_packets++;
+    }
+
+out:
+  CLIB_MEMORY_BARRIER ();
+  txvq->used->idx = txvq->last_used_idx;
+  vhost_user_log_dirty_ring (vui, txvq, idx);
+  return discarded_packets;
+}
+
+/*
+ * In case of overflow, we need to rewind the array of allocated buffers.
+ */
+static __clib_unused void
+vhost_user_input_rewind_buffers (vlib_main_t * vm,
+				 vhost_cpu_t * cpu, vlib_buffer_t * b_head)
+{
+  u32 bi_current = cpu->rx_buffers[cpu->rx_buffers_len];
+  vlib_buffer_t *b_current = vlib_get_buffer (vm, bi_current);
+  b_current->current_length = 0;
+  b_current->flags = 0;
+  while (b_current != b_head)
+    {
+      cpu->rx_buffers_len++;
+      bi_current = cpu->rx_buffers[cpu->rx_buffers_len];
+      b_current = vlib_get_buffer (vm, bi_current);
+      b_current->current_length = 0;
+      b_current->flags = 0;
+    }
+  cpu->rx_buffers_len++;
+}
+
+static __clib_unused u32
+vhost_user_if_input (vlib_main_t * vm,
+		     vhost_user_main_t * vum,
+		     vhost_user_intf_t * vui,
+		     u16 qid, vlib_node_runtime_t * node,
+		     vnet_hw_interface_rx_mode mode)
+{
+  vhost_user_vring_t *txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)];
+  u16 n_rx_packets = 0;
+  u32 n_rx_bytes = 0;
+  u16 n_left;
+  u32 n_left_to_next, *to_next;
+  u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
+  u32 n_trace = vlib_get_trace_count (vm, node);
+  u32 map_hint = 0;
+  u16 thread_index = vlib_get_thread_index ();
+  u16 copy_len = 0;
+
+  {
+    /* do we have pending interrupts ? */
+    vhost_user_vring_t *rxvq = &vui->vrings[VHOST_VRING_IDX_RX (qid)];
+    f64 now = vlib_time_now (vm);
+
+    if ((txvq->n_since_last_int) && (txvq->int_deadline < now))
+      vhost_user_send_call (vm, txvq);
+
+    if ((rxvq->n_since_last_int) && (rxvq->int_deadline < now))
+      vhost_user_send_call (vm, rxvq);
+  }
+
+  /*
+   * For adaptive mode, it is optimized to reduce interrupts.
+   * If the scheduler switches the input node to polling due
+   * to burst of traffic, we tell the driver no interrupt.
+   * When the traffic subsides, the scheduler switches the node back to
+   * interrupt mode. We must tell the driver we want interrupt.
+   */
+  if (PREDICT_FALSE (mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE))
+    {
+      if ((node->flags &
+	   VLIB_NODE_FLAG_SWITCH_FROM_POLLING_TO_INTERRUPT_MODE) ||
+	  !(node->flags &
+	    VLIB_NODE_FLAG_SWITCH_FROM_INTERRUPT_TO_POLLING_MODE))
+	/* Tell driver we want notification */
+	txvq->used->flags = 0;
+      else
+	/* Tell driver we don't want notification */
+	txvq->used->flags = VRING_USED_F_NO_NOTIFY;
+    }
+
+  if (PREDICT_FALSE (txvq->avail->flags & 0xFFFE))
+    return 0;
+
+  n_left = (u16) (txvq->avail->idx - txvq->last_avail_idx);
+
+  /* nothing to do */
+  if (PREDICT_FALSE (n_left == 0))
+    return 0;
+
+  if (PREDICT_FALSE (!vui->admin_up || !(txvq->enabled)))
+    {
+      /*
+       * Discard input packet if interface is admin down or vring is not
+       * enabled.
+       * "For example, for a networking device, in the disabled state
+       * client must not supply any new RX packets, but must process
+       * and discard any TX packets."
+       */
+      vhost_user_rx_discard_packet (vm, vui, txvq,
+				    VHOST_USER_DOWN_DISCARD_COUNT);
+      return 0;
+    }
+
+  if (PREDICT_FALSE (n_left == (txvq->qsz_mask + 1)))
+    {
+      /*
+       * Informational error logging when VPP is not
+       * receiving packets fast enough.
+       */
+      vlib_error_count (vm, node->node_index,
+			VHOST_USER_INPUT_FUNC_ERROR_FULL_RX_QUEUE, 1);
+    }
+
+  if (n_left > VLIB_FRAME_SIZE)
+    n_left = VLIB_FRAME_SIZE;
+
+  /*
+   * For small packets (<2kB), we will not need more than one vlib buffer
+   * per packet. In case packets are bigger, we will just yeld at some point
+   * in the loop and come back later. This is not an issue as for big packet,
+   * processing cost really comes from the memory copy.
+   * The assumption is that big packets will fit in 40 buffers.
+   */
+  if (PREDICT_FALSE (vum->cpus[thread_index].rx_buffers_len < n_left + 1 ||
+		     vum->cpus[thread_index].rx_buffers_len < 40))
+    {
+      u32 curr_len = vum->cpus[thread_index].rx_buffers_len;
+      vum->cpus[thread_index].rx_buffers_len +=
+	vlib_buffer_alloc_from_free_list (vm,
+					  vum->cpus[thread_index].rx_buffers +
+					  curr_len,
+					  VHOST_USER_RX_BUFFERS_N - curr_len,
+					  VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
+
+      if (PREDICT_FALSE
+	  (vum->cpus[thread_index].rx_buffers_len <
+	   VHOST_USER_RX_BUFFER_STARVATION))
+	{
+	  /* In case of buffer starvation, discard some packets from the queue
+	   * and log the event.
+	   * We keep doing best effort for the remaining packets. */
+	  u32 flush = (n_left + 1 > vum->cpus[thread_index].rx_buffers_len) ?
+	    n_left + 1 - vum->cpus[thread_index].rx_buffers_len : 1;
+	  flush = vhost_user_rx_discard_packet (vm, vui, txvq, flush);
+
+	  n_left -= flush;
+	  vlib_increment_simple_counter (vnet_main.
+					 interface_main.sw_if_counters +
+					 VNET_INTERFACE_COUNTER_DROP,
+					 vlib_get_thread_index (),
+					 vui->sw_if_index, flush);
+
+	  vlib_error_count (vm, vhost_user_input_node.index,
+			    VHOST_USER_INPUT_FUNC_ERROR_NO_BUFFER, flush);
+	}
+    }
+
+  while (n_left > 0)
+    {
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left > 0 && n_left_to_next > 0)
+	{
+	  vlib_buffer_t *b_head, *b_current;
+	  u32 bi_current;
+	  u16 desc_current;
+	  u32 desc_data_offset;
+	  vring_desc_t *desc_table = txvq->desc;
+
+	  if (PREDICT_FALSE (vum->cpus[thread_index].rx_buffers_len <= 1))
+	    {
+	      /* Not enough rx_buffers
+	       * Note: We yeld on 1 so we don't need to do an additional
+	       * check for the next buffer prefetch.
+	       */
+	      n_left = 0;
+	      break;
+	    }
+
+	  desc_current =
+	    txvq->avail->ring[txvq->last_avail_idx & txvq->qsz_mask];
+	  vum->cpus[thread_index].rx_buffers_len--;
+	  bi_current = (vum->cpus[thread_index].rx_buffers)
+	    [vum->cpus[thread_index].rx_buffers_len];
+	  b_head = b_current = vlib_get_buffer (vm, bi_current);
+	  to_next[0] = bi_current;	//We do that now so we can forget about bi_current
+	  to_next++;
+	  n_left_to_next--;
+
+	  vlib_prefetch_buffer_with_index (vm,
+					   (vum->
+					    cpus[thread_index].rx_buffers)
+					   [vum->cpus[thread_index].
+					    rx_buffers_len - 1], LOAD);
+
+	  /* Just preset the used descriptor id and length for later */
+	  txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].id =
+	    desc_current;
+	  txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].len = 0;
+	  vhost_user_log_dirty_ring (vui, txvq,
+				     ring[txvq->last_used_idx &
+					  txvq->qsz_mask]);
+
+	  /* The buffer should already be initialized */
+	  b_head->total_length_not_including_first_buffer = 0;
+	  b_head->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
+
+	  if (PREDICT_FALSE (n_trace))
+	    {
+	      //TODO: next_index is not exactly known at that point
+	      vlib_trace_buffer (vm, node, next_index, b_head,
+				 /* follow_chain */ 0);
+	      vhost_trace_t *t0 =
+		vlib_add_trace (vm, node, b_head, sizeof (t0[0]));
+	      vhost_user_rx_trace (t0, vui, qid, b_head, txvq);
+	      n_trace--;
+	      vlib_set_trace_count (vm, node, n_trace);
+	    }
+
+	  /* This depends on the setup but is very consistent
+	   * So I think the CPU branch predictor will make a pretty good job
+	   * at optimizing the decision. */
+	  if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT)
+	    {
+	      desc_table = map_guest_mem (vui, txvq->desc[desc_current].addr,
+					  &map_hint);
+	      desc_current = 0;
+	      if (PREDICT_FALSE (desc_table == 0))
+		{
+		  vlib_error_count (vm, node->node_index,
+				    VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL, 1);
+		  goto out;
+		}
+	    }
+
+	  if (PREDICT_TRUE (vui->is_any_layout) ||
+	      (!(desc_table[desc_current].flags & VIRTQ_DESC_F_NEXT)))
+	    {
+	      /* ANYLAYOUT or single buffer */
+	      desc_data_offset = vui->virtio_net_hdr_sz;
+	    }
+	  else
+	    {
+	      /* CSR case without ANYLAYOUT, skip 1st buffer */
+	      desc_data_offset = desc_table[desc_current].len;
+	    }
+
+	  while (1)
+	    {
+	      /* Get more input if necessary. Or end of packet. */
+	      if (desc_data_offset == desc_table[desc_current].len)
+		{
+		  if (PREDICT_FALSE (desc_table[desc_current].flags &
+				     VIRTQ_DESC_F_NEXT))
+		    {
+		      desc_current = desc_table[desc_current].next;
+		      desc_data_offset = 0;
+		    }
+		  else
+		    {
+		      goto out;
+		    }
+		}
+
+	      /* Get more output if necessary. Or end of packet. */
+	      if (PREDICT_FALSE
+		  (b_current->current_length == VLIB_BUFFER_DATA_SIZE))
+		{
+		  if (PREDICT_FALSE
+		      (vum->cpus[thread_index].rx_buffers_len == 0))
+		    {
+		      /* Cancel speculation */
+		      to_next--;
+		      n_left_to_next++;
+
+		      /*
+		       * Checking if there are some left buffers.
+		       * If not, just rewind the used buffers and stop.
+		       * Note: Scheduled copies are not cancelled. This is
+		       * not an issue as they would still be valid. Useless,
+		       * but valid.
+		       */
+		      vhost_user_input_rewind_buffers (vm,
+						       &vum->cpus
+						       [thread_index],
+						       b_head);
+		      n_left = 0;
+		      goto stop;
+		    }
+
+		  /* Get next output */
+		  vum->cpus[thread_index].rx_buffers_len--;
+		  u32 bi_next =
+		    (vum->cpus[thread_index].rx_buffers)[vum->cpus
+							 [thread_index].rx_buffers_len];
+		  b_current->next_buffer = bi_next;
+		  b_current->flags |= VLIB_BUFFER_NEXT_PRESENT;
+		  bi_current = bi_next;
+		  b_current = vlib_get_buffer (vm, bi_current);
+		}
+
+	      /* Prepare a copy order executed later for the data */
+	      vhost_copy_t *cpy = &vum->cpus[thread_index].copy[copy_len];
+	      copy_len++;
+	      u32 desc_data_l =
+		desc_table[desc_current].len - desc_data_offset;
+	      cpy->len = VLIB_BUFFER_DATA_SIZE - b_current->current_length;
+	      cpy->len = (cpy->len > desc_data_l) ? desc_data_l : cpy->len;
+	      cpy->dst = (uword) (vlib_buffer_get_current (b_current) +
+				  b_current->current_length);
+	      cpy->src = desc_table[desc_current].addr + desc_data_offset;
+
+	      desc_data_offset += cpy->len;
+
+	      b_current->current_length += cpy->len;
+	      b_head->total_length_not_including_first_buffer += cpy->len;
+	    }
+
+	out:
+	  CLIB_PREFETCH (&n_left, sizeof (n_left), LOAD);
+
+	  n_rx_bytes += b_head->total_length_not_including_first_buffer;
+	  n_rx_packets++;
+
+	  b_head->total_length_not_including_first_buffer -=
+	    b_head->current_length;
+
+	  /* consume the descriptor and return it as used */
+	  txvq->last_avail_idx++;
+	  txvq->last_used_idx++;
+
+	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b_head);
+
+	  vnet_buffer (b_head)->sw_if_index[VLIB_RX] = vui->sw_if_index;
+	  vnet_buffer (b_head)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+	  b_head->error = 0;
+
+	  {
+	    u32 next0 = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
+
+	    /* redirect if feature path enabled */
+	    vnet_feature_start_device_input_x1 (vui->sw_if_index, &next0,
+						b_head);
+
+	    u32 bi = to_next[-1];	//Cannot use to_next[-1] in the macro
+	    vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					     to_next, n_left_to_next,
+					     bi, next0);
+	  }
+
+	  n_left--;
+
+	  /*
+	   * Although separating memory copies from virtio ring parsing
+	   * is beneficial, we can offer to perform the copies from time
+	   * to time in order to free some space in the ring.
+	   */
+	  if (PREDICT_FALSE (copy_len >= VHOST_USER_RX_COPY_THRESHOLD))
+	    {
+	      if (PREDICT_FALSE
+		  (vhost_user_input_copy (vui, vum->cpus[thread_index].copy,
+					  copy_len, &map_hint)))
+		{
+		  vlib_error_count (vm, node->node_index,
+				    VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL, 1);
+		}
+	      copy_len = 0;
+
+	      /* give buffers back to driver */
+	      CLIB_MEMORY_BARRIER ();
+	      txvq->used->idx = txvq->last_used_idx;
+	      vhost_user_log_dirty_ring (vui, txvq, idx);
+	    }
+	}
+    stop:
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  /* Do the memory copies */
+  if (PREDICT_FALSE
+      (vhost_user_input_copy (vui, vum->cpus[thread_index].copy,
+			      copy_len, &map_hint)))
+    {
+      vlib_error_count (vm, node->node_index,
+			VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL, 1);
+    }
+
+  /* give buffers back to driver */
+  CLIB_MEMORY_BARRIER ();
+  txvq->used->idx = txvq->last_used_idx;
+  vhost_user_log_dirty_ring (vui, txvq, idx);
+
+  /* interrupt (call) handling */
+  if ((txvq->callfd_idx != ~0) &&
+      !(txvq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
+    {
+      txvq->n_since_last_int += n_rx_packets;
+
+      if (txvq->n_since_last_int > vum->coalesce_frames)
+	vhost_user_send_call (vm, txvq);
+    }
+
+  /* increase rx counters */
+  vlib_increment_combined_counter
+    (vnet_main.interface_main.combined_sw_if_counters
+     + VNET_INTERFACE_COUNTER_RX,
+     vlib_get_thread_index (), vui->sw_if_index, n_rx_packets, n_rx_bytes);
+
+  vnet_device_increment_rx_packets (thread_index, n_rx_packets);
+
+  return n_rx_packets;
+}
+
+VLIB_NODE_FN (vhost_user_input_node) (vlib_main_t * vm,
+				      vlib_node_runtime_t * node,
+				      vlib_frame_t * frame)
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+  uword n_rx_packets = 0;
+  vhost_user_intf_t *vui;
+  vnet_device_input_runtime_t *rt =
+    (vnet_device_input_runtime_t *) node->runtime_data;
+  vnet_device_and_queue_t *dq;
+
+  vec_foreach (dq, rt->devices_and_queues)
+  {
+    if (clib_smp_swap (&dq->interrupt_pending, 0) ||
+	(node->state == VLIB_NODE_STATE_POLLING))
+      {
+	vui =
+	  pool_elt_at_index (vum->vhost_user_interfaces, dq->dev_instance);
+	n_rx_packets = vhost_user_if_input (vm, vum, vui, dq->queue_id, node,
+					    dq->mode);
+      }
+  }
+
+  return n_rx_packets;
+}
+
+#ifndef CLIB_MARCH_VARIANT
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (vhost_user_input_node) = {
+  .type = VLIB_NODE_TYPE_INPUT,
+  .name = "vhost-user-input",
+  .sibling_of = "device-input",
+
+  /* Will be enabled if/when hardware is detected. */
+  .state = VLIB_NODE_STATE_DISABLED,
+
+  .format_buffer = format_ethernet_header_with_length,
+  .format_trace = format_vhost_trace,
+
+  .n_errors = VHOST_USER_INPUT_FUNC_N_ERROR,
+  .error_strings = vhost_user_input_func_error_strings,
+};
+/* *INDENT-ON* */
+#endif
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/devices/virtio/vhost_user_output.c b/src/vnet/devices/virtio/vhost_user_output.c
new file mode 100644
index 0000000..f400f18
--- /dev/null
+++ b/src/vnet/devices/virtio/vhost_user_output.c
@@ -0,0 +1,671 @@
+/*
+ *------------------------------------------------------------------
+ * vhost-user-output
+ *
+ * Copyright (c) 2014-2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+#include <fcntl.h>		/* for open */
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/uio.h>		/* for iovec */
+#include <netinet/in.h>
+#include <sys/vfs.h>
+
+#include <linux/if_arp.h>
+#include <linux/if_tun.h>
+
+#include <vlib/vlib.h>
+#include <vlib/unix/unix.h>
+
+#include <vnet/ip/ip.h>
+
+#include <vnet/ethernet/ethernet.h>
+#include <vnet/devices/devices.h>
+#include <vnet/feature/feature.h>
+
+#include <vnet/devices/virtio/vhost_user.h>
+#include <vnet/devices/virtio/vhost_user_inline.h>
+
+/*
+ * On the transmit side, we keep processing the buffers from vlib in the while
+ * loop and prepare the copy order to be executed later. However, the static
+ * array which we keep the copy order is limited to VHOST_USER_COPY_ARRAY_N
+ * entries. In order to not corrupt memory, we have to do the copy when the
+ * static array reaches the copy threshold. We subtract 40 in case the code
+ * goes into the inner loop for a maximum of 64k frames which may require
+ * more array entries.
+ */
+#define VHOST_USER_TX_COPY_THRESHOLD (VHOST_USER_COPY_ARRAY_N - 40)
+
+vnet_device_class_t vhost_user_device_class;
+
+#define foreach_vhost_user_tx_func_error      \
+  _(NONE, "no error")  \
+  _(NOT_READY, "vhost vring not ready")  \
+  _(DOWN, "vhost interface is down")  \
+  _(PKT_DROP_NOBUF, "tx packet drops (no available descriptors)")  \
+  _(PKT_DROP_NOMRG, "tx packet drops (cannot merge descriptors)")  \
+  _(MMAP_FAIL, "mmap failure") \
+  _(INDIRECT_OVERFLOW, "indirect descriptor table overflow")
+
+typedef enum
+{
+#define _(f,s) VHOST_USER_TX_FUNC_ERROR_##f,
+  foreach_vhost_user_tx_func_error
+#undef _
+    VHOST_USER_TX_FUNC_N_ERROR,
+} vhost_user_tx_func_error_t;
+
+static __clib_unused char *vhost_user_tx_func_error_strings[] = {
+#define _(n,s) s,
+  foreach_vhost_user_tx_func_error
+#undef _
+};
+
+static __clib_unused u8 *
+format_vhost_user_interface_name (u8 * s, va_list * args)
+{
+  u32 i = va_arg (*args, u32);
+  u32 show_dev_instance = ~0;
+  vhost_user_main_t *vum = &vhost_user_main;
+
+  if (i < vec_len (vum->show_dev_instance_by_real_dev_instance))
+    show_dev_instance = vum->show_dev_instance_by_real_dev_instance[i];
+
+  if (show_dev_instance != ~0)
+    i = show_dev_instance;
+
+  s = format (s, "VirtualEthernet0/0/%d", i);
+  return s;
+}
+
+static __clib_unused int
+vhost_user_name_renumber (vnet_hw_interface_t * hi, u32 new_dev_instance)
+{
+  // FIXME: check if the new dev instance is already used
+  vhost_user_main_t *vum = &vhost_user_main;
+  vec_validate_init_empty (vum->show_dev_instance_by_real_dev_instance,
+			   hi->dev_instance, ~0);
+
+  vum->show_dev_instance_by_real_dev_instance[hi->dev_instance] =
+    new_dev_instance;
+
+  DBG_SOCK ("renumbered vhost-user interface dev_instance %d to %d",
+	    hi->dev_instance, new_dev_instance);
+
+  return 0;
+}
+
+/**
+ * @brief Try once to lock the vring
+ * @return 0 on success, non-zero on failure.
+ */
+static_always_inline int
+vhost_user_vring_try_lock (vhost_user_intf_t * vui, u32 qid)
+{
+  return __sync_lock_test_and_set (vui->vring_locks[qid], 1);
+}
+
+/**
+ * @brief Spin until the vring is successfully locked
+ */
+static_always_inline void
+vhost_user_vring_lock (vhost_user_intf_t * vui, u32 qid)
+{
+  while (vhost_user_vring_try_lock (vui, qid))
+    ;
+}
+
+/**
+ * @brief Unlock the vring lock
+ */
+static_always_inline void
+vhost_user_vring_unlock (vhost_user_intf_t * vui, u32 qid)
+{
+  *vui->vring_locks[qid] = 0;
+}
+
+static_always_inline void
+vhost_user_tx_trace (vhost_trace_t * t,
+		     vhost_user_intf_t * vui, u16 qid,
+		     vlib_buffer_t * b, vhost_user_vring_t * rxvq)
+{
+  vhost_user_main_t *vum = &vhost_user_main;
+  u32 last_avail_idx = rxvq->last_avail_idx;
+  u32 desc_current = rxvq->avail->ring[last_avail_idx & rxvq->qsz_mask];
+  vring_desc_t *hdr_desc = 0;
+  u32 hint = 0;
+
+  memset (t, 0, sizeof (*t));
+  t->device_index = vui - vum->vhost_user_interfaces;
+  t->qid = qid;
+
+  hdr_desc = &rxvq->desc[desc_current];
+  if (rxvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT)
+    {
+      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_INDIRECT;
+      /* Header is the first here */
+      hdr_desc = map_guest_mem (vui, rxvq->desc[desc_current].addr, &hint);
+    }
+  if (rxvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT)
+    {
+      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_SIMPLE_CHAINED;
+    }
+  if (!(rxvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT) &&
+      !(rxvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT))
+    {
+      t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_SINGLE_DESC;
+    }
+
+  t->first_desc_len = hdr_desc ? hdr_desc->len : 0;
+}
+
+static_always_inline u32
+vhost_user_tx_copy (vhost_user_intf_t * vui, vhost_copy_t * cpy,
+		    u16 copy_len, u32 * map_hint)
+{
+  void *dst0, *dst1, *dst2, *dst3;
+  if (PREDICT_TRUE (copy_len >= 4))
+    {
+      if (PREDICT_FALSE (!(dst2 = map_guest_mem (vui, cpy[0].dst, map_hint))))
+	return 1;
+      if (PREDICT_FALSE (!(dst3 = map_guest_mem (vui, cpy[1].dst, map_hint))))
+	return 1;
+      while (PREDICT_TRUE (copy_len >= 4))
+	{
+	  dst0 = dst2;
+	  dst1 = dst3;
+
+	  if (PREDICT_FALSE
+	      (!(dst2 = map_guest_mem (vui, cpy[2].dst, map_hint))))
+	    return 1;
+	  if (PREDICT_FALSE
+	      (!(dst3 = map_guest_mem (vui, cpy[3].dst, map_hint))))
+	    return 1;
+
+	  CLIB_PREFETCH ((void *) cpy[2].src, 64, LOAD);
+	  CLIB_PREFETCH ((void *) cpy[3].src, 64, LOAD);
+
+	  clib_memcpy (dst0, (void *) cpy[0].src, cpy[0].len);
+	  clib_memcpy (dst1, (void *) cpy[1].src, cpy[1].len);
+
+	  vhost_user_log_dirty_pages_2 (vui, cpy[0].dst, cpy[0].len, 1);
+	  vhost_user_log_dirty_pages_2 (vui, cpy[1].dst, cpy[1].len, 1);
+	  copy_len -= 2;
+	  cpy += 2;
+	}
+    }
+  while (copy_len)
+    {
+      if (PREDICT_FALSE (!(dst0 = map_guest_mem (vui, cpy->dst, map_hint))))
+	return 1;
+      clib_memcpy (dst0, (void *) cpy->src, cpy->len);
+      vhost_user_log_dirty_pages_2 (vui, cpy->dst, cpy->len, 1);
+      copy_len -= 1;
+      cpy += 1;
+    }
+  return 0;
+}
+
+
+uword
+CLIB_MULTIARCH_FN (vhost_user_tx) (vlib_main_t * vm,
+				   vlib_node_runtime_t * node,
+				   vlib_frame_t * frame)
+{
+  u32 *buffers = vlib_frame_args (frame);
+  u32 n_left = frame->n_vectors;
+  vhost_user_main_t *vum = &vhost_user_main;
+  vnet_interface_output_runtime_t *rd = (void *) node->runtime_data;
+  vhost_user_intf_t *vui =
+    pool_elt_at_index (vum->vhost_user_interfaces, rd->dev_instance);
+  u32 qid = ~0;
+  vhost_user_vring_t *rxvq;
+  u8 error;
+  u32 thread_index = vlib_get_thread_index ();
+  u32 map_hint = 0;
+  u8 retry = 8;
+  u16 copy_len;
+  u16 tx_headers_len;
+
+  if (PREDICT_FALSE (!vui->admin_up))
+    {
+      error = VHOST_USER_TX_FUNC_ERROR_DOWN;
+      goto done3;
+    }
+
+  if (PREDICT_FALSE (!vui->is_up))
+    {
+      error = VHOST_USER_TX_FUNC_ERROR_NOT_READY;
+      goto done3;
+    }
+
+  qid =
+    VHOST_VRING_IDX_RX (*vec_elt_at_index
+			(vui->per_cpu_tx_qid, thread_index));
+  rxvq = &vui->vrings[qid];
+  if (PREDICT_FALSE (vui->use_tx_spinlock))
+    vhost_user_vring_lock (vui, qid);
+
+retry:
+  error = VHOST_USER_TX_FUNC_ERROR_NONE;
+  tx_headers_len = 0;
+  copy_len = 0;
+  while (n_left > 0)
+    {
+      vlib_buffer_t *b0, *current_b0;
+      u16 desc_head, desc_index, desc_len;
+      vring_desc_t *desc_table;
+      uword buffer_map_addr;
+      u32 buffer_len;
+      u16 bytes_left;
+
+      if (PREDICT_TRUE (n_left > 1))
+	vlib_prefetch_buffer_with_index (vm, buffers[1], LOAD);
+
+      b0 = vlib_get_buffer (vm, buffers[0]);
+
+      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	{
+	  vum->cpus[thread_index].current_trace =
+	    vlib_add_trace (vm, node, b0,
+			    sizeof (*vum->cpus[thread_index].current_trace));
+	  vhost_user_tx_trace (vum->cpus[thread_index].current_trace,
+			       vui, qid / 2, b0, rxvq);
+	}
+
+      if (PREDICT_FALSE (rxvq->last_avail_idx == rxvq->avail->idx))
+	{
+	  error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF;
+	  goto done;
+	}
+
+      desc_table = rxvq->desc;
+      desc_head = desc_index =
+	rxvq->avail->ring[rxvq->last_avail_idx & rxvq->qsz_mask];
+
+      /* Go deeper in case of indirect descriptor
+       * I don't know of any driver providing indirect for RX. */
+      if (PREDICT_FALSE (rxvq->desc[desc_head].flags & VIRTQ_DESC_F_INDIRECT))
+	{
+	  if (PREDICT_FALSE
+	      (rxvq->desc[desc_head].len < sizeof (vring_desc_t)))
+	    {
+	      error = VHOST_USER_TX_FUNC_ERROR_INDIRECT_OVERFLOW;
+	      goto done;
+	    }
+	  if (PREDICT_FALSE
+	      (!(desc_table =
+		 map_guest_mem (vui, rxvq->desc[desc_index].addr,
+				&map_hint))))
+	    {
+	      error = VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL;
+	      goto done;
+	    }
+	  desc_index = 0;
+	}
+
+      desc_len = vui->virtio_net_hdr_sz;
+      buffer_map_addr = desc_table[desc_index].addr;
+      buffer_len = desc_table[desc_index].len;
+
+      {
+	// Get a header from the header array
+	virtio_net_hdr_mrg_rxbuf_t *hdr =
+	  &vum->cpus[thread_index].tx_headers[tx_headers_len];
+	tx_headers_len++;
+	hdr->hdr.flags = 0;
+	hdr->hdr.gso_type = 0;
+	hdr->num_buffers = 1;	//This is local, no need to check
+
+	// Prepare a copy order executed later for the header
+	vhost_copy_t *cpy = &vum->cpus[thread_index].copy[copy_len];
+	copy_len++;
+	cpy->len = vui->virtio_net_hdr_sz;
+	cpy->dst = buffer_map_addr;
+	cpy->src = (uword) hdr;
+      }
+
+      buffer_map_addr += vui->virtio_net_hdr_sz;
+      buffer_len -= vui->virtio_net_hdr_sz;
+      bytes_left = b0->current_length;
+      current_b0 = b0;
+      while (1)
+	{
+	  if (buffer_len == 0)
+	    {			//Get new output
+	      if (desc_table[desc_index].flags & VIRTQ_DESC_F_NEXT)
+		{
+		  //Next one is chained
+		  desc_index = desc_table[desc_index].next;
+		  buffer_map_addr = desc_table[desc_index].addr;
+		  buffer_len = desc_table[desc_index].len;
+		}
+	      else if (vui->virtio_net_hdr_sz == 12)	//MRG is available
+		{
+		  virtio_net_hdr_mrg_rxbuf_t *hdr =
+		    &vum->cpus[thread_index].tx_headers[tx_headers_len - 1];
+
+		  //Move from available to used buffer
+		  rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].id =
+		    desc_head;
+		  rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].len =
+		    desc_len;
+		  vhost_user_log_dirty_ring (vui, rxvq,
+					     ring[rxvq->last_used_idx &
+						  rxvq->qsz_mask]);
+
+		  rxvq->last_avail_idx++;
+		  rxvq->last_used_idx++;
+		  hdr->num_buffers++;
+		  desc_len = 0;
+
+		  if (PREDICT_FALSE
+		      (rxvq->last_avail_idx == rxvq->avail->idx))
+		    {
+		      //Dequeue queued descriptors for this packet
+		      rxvq->last_used_idx -= hdr->num_buffers - 1;
+		      rxvq->last_avail_idx -= hdr->num_buffers - 1;
+		      error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF;
+		      goto done;
+		    }
+
+		  desc_table = rxvq->desc;
+		  desc_head = desc_index =
+		    rxvq->avail->ring[rxvq->last_avail_idx & rxvq->qsz_mask];
+		  if (PREDICT_FALSE
+		      (rxvq->desc[desc_head].flags & VIRTQ_DESC_F_INDIRECT))
+		    {
+		      //It is seriously unlikely that a driver will put indirect descriptor
+		      //after non-indirect descriptor.
+		      if (PREDICT_FALSE
+			  (rxvq->desc[desc_head].len < sizeof (vring_desc_t)))
+			{
+			  error = VHOST_USER_TX_FUNC_ERROR_INDIRECT_OVERFLOW;
+			  goto done;
+			}
+		      if (PREDICT_FALSE
+			  (!(desc_table =
+			     map_guest_mem (vui,
+					    rxvq->desc[desc_index].addr,
+					    &map_hint))))
+			{
+			  error = VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL;
+			  goto done;
+			}
+		      desc_index = 0;
+		    }
+		  buffer_map_addr = desc_table[desc_index].addr;
+		  buffer_len = desc_table[desc_index].len;
+		}
+	      else
+		{
+		  error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOMRG;
+		  goto done;
+		}
+	    }
+
+	  {
+	    vhost_copy_t *cpy = &vum->cpus[thread_index].copy[copy_len];
+	    copy_len++;
+	    cpy->len = bytes_left;
+	    cpy->len = (cpy->len > buffer_len) ? buffer_len : cpy->len;
+	    cpy->dst = buffer_map_addr;
+	    cpy->src = (uword) vlib_buffer_get_current (current_b0) +
+	      current_b0->current_length - bytes_left;
+
+	    bytes_left -= cpy->len;
+	    buffer_len -= cpy->len;
+	    buffer_map_addr += cpy->len;
+	    desc_len += cpy->len;
+
+	    CLIB_PREFETCH (&rxvq->desc, CLIB_CACHE_LINE_BYTES, LOAD);
+	  }
+
+	  // Check if vlib buffer has more data. If not, get more or break.
+	  if (PREDICT_TRUE (!bytes_left))
+	    {
+	      if (PREDICT_FALSE
+		  (current_b0->flags & VLIB_BUFFER_NEXT_PRESENT))
+		{
+		  current_b0 = vlib_get_buffer (vm, current_b0->next_buffer);
+		  bytes_left = current_b0->current_length;
+		}
+	      else
+		{
+		  //End of packet
+		  break;
+		}
+	    }
+	}
+
+      //Move from available to used ring
+      rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].id = desc_head;
+      rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].len = desc_len;
+      vhost_user_log_dirty_ring (vui, rxvq,
+				 ring[rxvq->last_used_idx & rxvq->qsz_mask]);
+      rxvq->last_avail_idx++;
+      rxvq->last_used_idx++;
+
+      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	{
+	  vum->cpus[thread_index].current_trace->hdr =
+	    vum->cpus[thread_index].tx_headers[tx_headers_len - 1];
+	}
+
+      n_left--;			//At the end for error counting when 'goto done' is invoked
+
+      /*
+       * Do the copy periodically to prevent
+       * vum->cpus[thread_index].copy array overflow and corrupt memory
+       */
+      if (PREDICT_FALSE (copy_len >= VHOST_USER_TX_COPY_THRESHOLD))
+	{
+	  if (PREDICT_FALSE
+	      (vhost_user_tx_copy (vui, vum->cpus[thread_index].copy,
+				   copy_len, &map_hint)))
+	    {
+	      vlib_error_count (vm, node->node_index,
+				VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL, 1);
+	    }
+	  copy_len = 0;
+
+	  /* give buffers back to driver */
+	  CLIB_MEMORY_BARRIER ();
+	  rxvq->used->idx = rxvq->last_used_idx;
+	  vhost_user_log_dirty_ring (vui, rxvq, idx);
+	}
+      buffers++;
+    }
+
+done:
+  //Do the memory copies
+  if (PREDICT_FALSE
+      (vhost_user_tx_copy (vui, vum->cpus[thread_index].copy,
+			   copy_len, &map_hint)))
+    {
+      vlib_error_count (vm, node->node_index,
+			VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL, 1);
+    }
+
+  CLIB_MEMORY_BARRIER ();
+  rxvq->used->idx = rxvq->last_used_idx;
+  vhost_user_log_dirty_ring (vui, rxvq, idx);
+
+  /*
+   * When n_left is set, error is always set to something too.
+   * In case error is due to lack of remaining buffers, we go back up and
+   * retry.
+   * The idea is that it is better to waste some time on packets
+   * that have been processed already than dropping them and get
+   * more fresh packets with a good likelyhood that they will be dropped too.
+   * This technique also gives more time to VM driver to pick-up packets.
+   * In case the traffic flows from physical to virtual interfaces, this
+   * technique will end-up leveraging the physical NIC buffer in order to
+   * absorb the VM's CPU jitter.
+   */
+  if (n_left && (error == VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF) && retry)
+    {
+      retry--;
+      goto retry;
+    }
+
+  /* interrupt (call) handling */
+  if ((rxvq->callfd_idx != ~0) &&
+      !(rxvq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
+    {
+      rxvq->n_since_last_int += frame->n_vectors - n_left;
+
+      if (rxvq->n_since_last_int > vum->coalesce_frames)
+	vhost_user_send_call (vm, rxvq);
+    }
+
+  vhost_user_vring_unlock (vui, qid);
+
+done3:
+  if (PREDICT_FALSE (n_left && error != VHOST_USER_TX_FUNC_ERROR_NONE))
+    {
+      vlib_error_count (vm, node->node_index, error, n_left);
+      vlib_increment_simple_counter
+	(vnet_main.interface_main.sw_if_counters
+	 + VNET_INTERFACE_COUNTER_DROP,
+	 thread_index, vui->sw_if_index, n_left);
+    }
+
+  vlib_buffer_free (vm, vlib_frame_args (frame), frame->n_vectors);
+  return frame->n_vectors;
+}
+
+static __clib_unused clib_error_t *
+vhost_user_interface_rx_mode_change (vnet_main_t * vnm, u32 hw_if_index,
+				     u32 qid, vnet_hw_interface_rx_mode mode)
+{
+  vlib_main_t *vm = vnm->vlib_main;
+  vnet_hw_interface_t *hif = vnet_get_hw_interface (vnm, hw_if_index);
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui =
+    pool_elt_at_index (vum->vhost_user_interfaces, hif->dev_instance);
+  vhost_user_vring_t *txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)];
+
+  if ((mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT) ||
+      (mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE))
+    {
+      if (txvq->kickfd_idx == ~0)
+	{
+	  // We cannot support interrupt mode if the driver opts out
+	  return clib_error_return (0, "Driver does not support interrupt");
+	}
+      if (txvq->mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
+	{
+	  vum->ifq_count++;
+	  // Start the timer if this is the first encounter on interrupt
+	  // interface/queue
+	  if ((vum->ifq_count == 1) &&
+	      (vum->coalesce_time > 0.0) && (vum->coalesce_frames > 0))
+	    vlib_process_signal_event (vm,
+				       vhost_user_send_interrupt_node.index,
+				       VHOST_USER_EVENT_START_TIMER, 0);
+	}
+    }
+  else if (mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
+    {
+      if (((txvq->mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT) ||
+	   (txvq->mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE)) &&
+	  vum->ifq_count)
+	{
+	  vum->ifq_count--;
+	  // Stop the timer if there is no more interrupt interface/queue
+	  if ((vum->ifq_count == 0) &&
+	      (vum->coalesce_time > 0.0) && (vum->coalesce_frames > 0))
+	    vlib_process_signal_event (vm,
+				       vhost_user_send_interrupt_node.index,
+				       VHOST_USER_EVENT_STOP_TIMER, 0);
+	}
+    }
+
+  txvq->mode = mode;
+  if (mode == VNET_HW_INTERFACE_RX_MODE_POLLING)
+    txvq->used->flags = VRING_USED_F_NO_NOTIFY;
+  else if ((mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE) ||
+	   (mode == VNET_HW_INTERFACE_RX_MODE_INTERRUPT))
+    txvq->used->flags = 0;
+  else
+    {
+      clib_warning ("BUG: unhandled mode %d changed for if %d queue %d", mode,
+		    hw_if_index, qid);
+      return clib_error_return (0, "unsupported");
+    }
+
+  return 0;
+}
+
+static __clib_unused clib_error_t *
+vhost_user_interface_admin_up_down (vnet_main_t * vnm, u32 hw_if_index,
+				    u32 flags)
+{
+  vnet_hw_interface_t *hif = vnet_get_hw_interface (vnm, hw_if_index);
+  vhost_user_main_t *vum = &vhost_user_main;
+  vhost_user_intf_t *vui =
+    pool_elt_at_index (vum->vhost_user_interfaces, hif->dev_instance);
+  u32 hw_flags = 0;
+  vui->admin_up = (flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) != 0;
+  hw_flags = vui->admin_up ? VNET_HW_INTERFACE_FLAG_LINK_UP : 0;
+
+  vnet_hw_interface_set_flags (vnm, vui->hw_if_index, hw_flags);
+
+  return /* no error */ 0;
+}
+
+#ifndef CLIB_MARCH_VARIANT
+/* *INDENT-OFF* */
+VNET_DEVICE_CLASS (vhost_user_device_class) = {
+  .name = "vhost-user",
+  .tx_function = vhost_user_tx,
+  .tx_function_n_errors = VHOST_USER_TX_FUNC_N_ERROR,
+  .tx_function_error_strings = vhost_user_tx_func_error_strings,
+  .format_device_name = format_vhost_user_interface_name,
+  .name_renumber = vhost_user_name_renumber,
+  .admin_up_down_function = vhost_user_interface_admin_up_down,
+  .rx_mode_change_function = vhost_user_interface_rx_mode_change,
+  .format_tx_trace = format_vhost_trace,
+};
+
+#if __x86_64__
+vlib_node_function_t __clib_weak vhost_user_tx_avx512;
+vlib_node_function_t __clib_weak vhost_user_tx_avx2;
+static void __clib_constructor
+vhost_user_tx_multiarch_select (void)
+{
+  if (vhost_user_tx_avx512 && clib_cpu_supports_avx512f ())
+    vhost_user_device_class.tx_function = vhost_user_tx_avx512;
+  else if (vhost_user_tx_avx2 && clib_cpu_supports_avx2 ())
+    vhost_user_device_class.tx_function = vhost_user_tx_avx2;
+}
+#endif
+#endif
+
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */