src/vnet/devices/virtio/virtio.c - fdio/vpp - Gitiles

 /*
  *------------------------------------------------------------------
  * Copyright (c) 2017 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 <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <net/if.h>
 #include <linux/if_tun.h>
 #include <sys/ioctl.h>
 #include <linux/virtio_net.h>
 #include <linux/vhost.h>
 #include <sys/eventfd.h>

 #include <vlib/vlib.h>
 #include <vlib/pci/pci.h>
 #include <vlib/unix/unix.h>
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/ip/ip4_packet.h>
 #include <vnet/ip/ip6_packet.h>
 #include <vnet/devices/virtio/virtio.h>
 #include <vnet/devices/virtio/pci.h>

 virtio_main_t virtio_main;

 #define _IOCTL(fd,a,...) \
   if (ioctl (fd, a, __VA_ARGS__) < 0) \
     { \
       err = clib_error_return_unix (0, "ioctl(" #a ")"); \
       goto error; \
     }

 static clib_error_t *
 call_read_ready (clib_file_t * uf)
 {
   virtio_main_t *nm = &virtio_main;
   vnet_main_t *vnm = vnet_get_main ();
   u16 qid = uf->private_data & 0xFFFF;
   virtio_if_t *vif =
     vec_elt_at_index (nm->interfaces, uf->private_data >> 16);
   u64 b;

   CLIB_UNUSED (ssize_t size) = read (uf->file_descriptor, &b, sizeof (b));
   if ((qid & 1) == 0)
     vnet_device_input_set_interrupt_pending (vnm, vif->hw_if_index, qid);

   return 0;
 }


 clib_error_t *
 virtio_vring_init (vlib_main_t * vm, virtio_if_t * vif, u16 idx, u16 sz)
 {
   clib_error_t *err = 0;
   virtio_vring_t *vring;
   struct vhost_vring_state state = { 0 };
   struct vhost_vring_addr addr = { 0 };
   struct vhost_vring_file file = { 0 };
   clib_file_t t = { 0 };
   int i;

   if (!is_pow2 (sz))
     return clib_error_return (0, "ring size must be power of 2");

   if (sz > 32768)
     return clib_error_return (0, "ring size must be 32768 or lower");

   if (sz == 0)
     sz = 256;

   vec_validate_aligned (vif->vrings, idx, CLIB_CACHE_LINE_BYTES);
   vring = vec_elt_at_index (vif->vrings, idx);

   i = sizeof (struct vring_desc) * sz;
   i = round_pow2 (i, CLIB_CACHE_LINE_BYTES);
   vring->desc = clib_mem_alloc_aligned (i, CLIB_CACHE_LINE_BYTES);
   clib_memset (vring->desc, 0, i);

   i = sizeof (struct vring_avail) + sz * sizeof (vring->avail->ring[0]);
   i = round_pow2 (i, CLIB_CACHE_LINE_BYTES);
   vring->avail = clib_mem_alloc_aligned (i, CLIB_CACHE_LINE_BYTES);
   clib_memset (vring->avail, 0, i);
   // tell kernel that we don't need interrupt
   vring->avail->flags = VIRTIO_RING_FLAG_MASK_INT;

   i = sizeof (struct vring_used) + sz * sizeof (struct vring_used_elem);
   i = round_pow2 (i, CLIB_CACHE_LINE_BYTES);
   vring->used = clib_mem_alloc_aligned (i, CLIB_CACHE_LINE_BYTES);
   clib_memset (vring->used, 0, i);

   ASSERT (vring->buffers == 0);
   vec_validate_aligned (vring->buffers, sz, CLIB_CACHE_LINE_BYTES);
   ASSERT (vring->indirect_buffers == 0);
   vec_validate_aligned (vring->indirect_buffers, sz, CLIB_CACHE_LINE_BYTES);
   if (idx % 2)
     {
       u32 n_alloc = 0;
       do
 	{
 	  if (n_alloc < sz)
 	    n_alloc =
 	      vlib_buffer_alloc (vm, vring->indirect_buffers + n_alloc,
 				 sz - n_alloc);
 	}
       while (n_alloc != sz);
     }

   vring->size = sz;
   vring->call_fd = eventfd (0, EFD_NONBLOCK | EFD_CLOEXEC);
   vring->kick_fd = eventfd (0, EFD_CLOEXEC);

   t.read_function = call_read_ready;
   t.file_descriptor = vring->call_fd;
   t.private_data = vif->dev_instance << 16 | idx;
   t.description = format (0, "%U vring %u", format_virtio_device_name,
 			  vif->dev_instance, idx);
   vring->call_file_index = clib_file_add (&file_main, &t);

   state.index = idx;
   state.num = sz;
   _IOCTL (vif->fd, VHOST_SET_VRING_NUM, &state);

   addr.index = idx;
   addr.flags = 0;
   addr.desc_user_addr = pointer_to_uword (vring->desc);
   addr.avail_user_addr = pointer_to_uword (vring->avail);
   addr.used_user_addr = pointer_to_uword (vring->used);
   _IOCTL (vif->fd, VHOST_SET_VRING_ADDR, &addr);

   file.index = idx;
   file.fd = vring->kick_fd;
   _IOCTL (vif->fd, VHOST_SET_VRING_KICK, &file);
   file.fd = vring->call_fd;
   _IOCTL (vif->fd, VHOST_SET_VRING_CALL, &file);
   file.fd = vif->tap_fd;
   _IOCTL (vif->fd, VHOST_NET_SET_BACKEND, &file);

 error:
   return err;
 }

 inline void
 virtio_free_rx_buffers (vlib_main_t * vm, virtio_vring_t * vring)
 {
   u16 used = vring->desc_in_use;
   u16 last = vring->last_used_idx;
   u16 mask = vring->size - 1;

   while (used)
     {
       vlib_buffer_free (vm, &vring->buffers[last & mask], 1);
       last++;
       used--;
     }
 }

 clib_error_t *
 virtio_vring_free (vlib_main_t * vm, virtio_if_t * vif, u32 idx)
 {
   virtio_vring_t *vring = vec_elt_at_index (vif->vrings, idx);

   clib_file_del_by_index (&file_main, vring->call_file_index);
   close (vring->kick_fd);
   close (vring->call_fd);
   if (vring->used)
     {
       if ((idx & 1) == 1)
 	virtio_free_used_desc (vm, vring);
       else
 	virtio_free_rx_buffers (vm, vring);
       clib_mem_free (vring->used);
     }
   if (vring->desc)
     clib_mem_free (vring->desc);
   if (vring->avail)
     clib_mem_free (vring->avail);
   if (vring->queue_id % 2)
     {
       vlib_buffer_free_no_next (vm, vring->indirect_buffers, vring->size);
     }
   vec_free (vring->buffers);
   vec_free (vring->indirect_buffers);
   return 0;
 }

 inline void
 virtio_set_net_hdr_size (virtio_if_t * vif)
 {
   if (vif->features & VIRTIO_FEATURE (VIRTIO_NET_F_MRG_RXBUF) ||
       vif->features & VIRTIO_FEATURE (VIRTIO_F_VERSION_1))
     vif->virtio_net_hdr_sz = sizeof (struct virtio_net_hdr_v1);
   else
     vif->virtio_net_hdr_sz = sizeof (struct virtio_net_hdr);
 }

 inline void
 virtio_show (vlib_main_t * vm, u32 * hw_if_indices, u8 show_descr, u32 type)
 {
   u32 i, j, hw_if_index;
   virtio_if_t *vif;
   vnet_main_t *vnm = &vnet_main;
   virtio_main_t *mm = &virtio_main;
   virtio_vring_t *vring;
   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_features
 #undef _
     {.str = NULL}
   };

   struct feat_struct *flag_entry;
   static struct feat_struct flags_array[] = {
 #define _(b,e,s) { .bit = b, .str = s, },
     foreach_virtio_if_flag
 #undef _
     {.str = NULL}
   };

   if (!hw_if_indices)
     return;

   for (hw_if_index = 0; hw_if_index < vec_len (hw_if_indices); hw_if_index++)
     {
       vnet_hw_interface_t *hi =
 	vnet_get_hw_interface (vnm, hw_if_indices[hw_if_index]);
       vif = pool_elt_at_index (mm->interfaces, hi->dev_instance);
       if (vif->type != type)
 	continue;
       vlib_cli_output (vm, "Interface: %U (ifindex %d)",
 		       format_vnet_hw_if_index_name, vnm,
 		       hw_if_indices[hw_if_index], vif->hw_if_index);
       if (type == VIRTIO_IF_TYPE_PCI)
 	{
 	  vlib_cli_output (vm, "  PCI Address: %U", format_vlib_pci_addr,
 			   &vif->pci_addr);
 	}
       if (type == VIRTIO_IF_TYPE_TAP)
 	{
 	  if (vif->host_if_name)
 	    vlib_cli_output (vm, "  name \"%s\"", vif->host_if_name);
 	  if (vif->net_ns)
 	    vlib_cli_output (vm, "  host-ns \"%s\"", vif->net_ns);
 	  vlib_cli_output (vm, "  fd %d", vif->fd);
 	  vlib_cli_output (vm, "  tap-fd %d", vif->tap_fd);
 	}
       vlib_cli_output (vm, "  Mac Address: %U", format_ethernet_address,
 		       vif->mac_addr);
       vlib_cli_output (vm, "  Device instance: %u", vif->dev_instance);
       vlib_cli_output (vm, "  flags 0x%x", vif->flags);
       flag_entry = (struct feat_struct *) &flags_array;
       while (flag_entry->str)
 	{
 	  if (vif->flags & (1ULL << flag_entry->bit))
 	    vlib_cli_output (vm, "    %s (%d)", flag_entry->str,
 			     flag_entry->bit);
 	  flag_entry++;
 	}
       if (type == VIRTIO_IF_TYPE_PCI)
 	{
 	  device_status (vm, vif);
 	}
       vlib_cli_output (vm, "  features 0x%lx", vif->features);
       feat_entry = (struct feat_struct *) &feat_array;
       while (feat_entry->str)
 	{
 	  if (vif->features & (1ULL << feat_entry->bit))
 	    vlib_cli_output (vm, "    %s (%d)", feat_entry->str,
 			     feat_entry->bit);
 	  feat_entry++;
 	}
       vlib_cli_output (vm, "  remote-features 0x%lx", vif->remote_features);
       feat_entry = (struct feat_struct *) &feat_array;
       while (feat_entry->str)
 	{
 	  if (vif->remote_features & (1ULL << feat_entry->bit))
 	    vlib_cli_output (vm, "    %s (%d)", feat_entry->str,
 			     feat_entry->bit);
 	  feat_entry++;
 	}
       vec_foreach_index (i, vif->vrings)
       {
 	// RX = 0, TX = 1
 	vring = vec_elt_at_index (vif->vrings, i);
 	vlib_cli_output (vm, "  Virtqueue (%s)", (i & 1) ? "TX" : "RX");
 	vlib_cli_output (vm,
 			 "    qsz %d, last_used_idx %d, desc_next %d, desc_in_use %d",
 			 vring->size, vring->last_used_idx, vring->desc_next,
 			 vring->desc_in_use);
 	vlib_cli_output (vm,
 			 "    avail.flags 0x%x avail.idx %d used.flags 0x%x used.idx %d",
 			 vring->avail->flags, vring->avail->idx,
 			 vring->used->flags, vring->used->idx);
 	if (type == VIRTIO_IF_TYPE_TAP)
 	  {
 	    vlib_cli_output (vm, "    kickfd %d, callfd %d", vring->kick_fd,
 			     vring->call_fd);
 	  }
 	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");
 	    vring = vif->vrings;
 	    for (j = 0; j < vring->size; j++)
 	      {
 		struct vring_desc *desc = &vring->desc[j];
 		vlib_cli_output (vm,
 				 "  %-5d 0x%016lx %-5d 0x%04x %-5d 0x%016lx\n",
 				 j, desc->addr,
 				 desc->len,
 				 desc->flags, desc->next, desc->addr);
 	      }
 	  }
       }
     }

 }

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	*------------------------------------------------------------------
	* Copyright (c) 2017 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 <sys/types.h>
	#include <sys/stat.h>
	#include <fcntl.h>
	#include <net/if.h>
	#include <linux/if_tun.h>
	#include <sys/ioctl.h>
	#include <linux/virtio_net.h>
	#include <linux/vhost.h>
	#include <sys/eventfd.h>

	#include <vlib/vlib.h>
	#include <vlib/pci/pci.h>
	#include <vlib/unix/unix.h>
	#include <vnet/ethernet/ethernet.h>
	#include <vnet/ip/ip4_packet.h>
	#include <vnet/ip/ip6_packet.h>
	#include <vnet/devices/virtio/virtio.h>
	#include <vnet/devices/virtio/pci.h>

	virtio_main_t virtio_main;

	#define _IOCTL(fd,a,...) \
	if (ioctl (fd, a, __VA_ARGS__) < 0) \
	{ \
	err = clib_error_return_unix (0, "ioctl(" #a ")"); \
	goto error; \
	}

	static clib_error_t *
	call_read_ready (clib_file_t * uf)
	{
	virtio_main_t *nm = &virtio_main;
	vnet_main_t *vnm = vnet_get_main ();
	u16 qid = uf->private_data & 0xFFFF;
	virtio_if_t *vif =
	vec_elt_at_index (nm->interfaces, uf->private_data >> 16);
	u64 b;

	CLIB_UNUSED (ssize_t size) = read (uf->file_descriptor, &b, sizeof (b));
	if ((qid & 1) == 0)
	vnet_device_input_set_interrupt_pending (vnm, vif->hw_if_index, qid);

	return 0;
	}


	clib_error_t *
	virtio_vring_init (vlib_main_t * vm, virtio_if_t * vif, u16 idx, u16 sz)
	{
	clib_error_t *err = 0;
	virtio_vring_t *vring;
	struct vhost_vring_state state = { 0 };
	struct vhost_vring_addr addr = { 0 };
	struct vhost_vring_file file = { 0 };
	clib_file_t t = { 0 };
	int i;

	if (!is_pow2 (sz))
	return clib_error_return (0, "ring size must be power of 2");

	if (sz > 32768)
	return clib_error_return (0, "ring size must be 32768 or lower");

	if (sz == 0)
	sz = 256;

	vec_validate_aligned (vif->vrings, idx, CLIB_CACHE_LINE_BYTES);
	vring = vec_elt_at_index (vif->vrings, idx);

	i = sizeof (struct vring_desc) * sz;
	i = round_pow2 (i, CLIB_CACHE_LINE_BYTES);
	vring->desc = clib_mem_alloc_aligned (i, CLIB_CACHE_LINE_BYTES);
	clib_memset (vring->desc, 0, i);

	i = sizeof (struct vring_avail) + sz * sizeof (vring->avail->ring[0]);
	i = round_pow2 (i, CLIB_CACHE_LINE_BYTES);
	vring->avail = clib_mem_alloc_aligned (i, CLIB_CACHE_LINE_BYTES);
	clib_memset (vring->avail, 0, i);
	// tell kernel that we don't need interrupt
	vring->avail->flags = VIRTIO_RING_FLAG_MASK_INT;

	i = sizeof (struct vring_used) + sz * sizeof (struct vring_used_elem);
	i = round_pow2 (i, CLIB_CACHE_LINE_BYTES);
	vring->used = clib_mem_alloc_aligned (i, CLIB_CACHE_LINE_BYTES);
	clib_memset (vring->used, 0, i);

	ASSERT (vring->buffers == 0);
	vec_validate_aligned (vring->buffers, sz, CLIB_CACHE_LINE_BYTES);
	ASSERT (vring->indirect_buffers == 0);
	vec_validate_aligned (vring->indirect_buffers, sz, CLIB_CACHE_LINE_BYTES);
	if (idx % 2)
	{
	u32 n_alloc = 0;
	do
	{
	if (n_alloc < sz)
	n_alloc =
	vlib_buffer_alloc (vm, vring->indirect_buffers + n_alloc,
	sz - n_alloc);
	}
	while (n_alloc != sz);
	}

	vring->size = sz;
	vring->call_fd = eventfd (0, EFD_NONBLOCK \| EFD_CLOEXEC);
	vring->kick_fd = eventfd (0, EFD_CLOEXEC);

	t.read_function = call_read_ready;
	t.file_descriptor = vring->call_fd;
	t.private_data = vif->dev_instance << 16 \| idx;
	t.description = format (0, "%U vring %u", format_virtio_device_name,
	vif->dev_instance, idx);
	vring->call_file_index = clib_file_add (&file_main, &t);

	state.index = idx;
	state.num = sz;
	_IOCTL (vif->fd, VHOST_SET_VRING_NUM, &state);

	addr.index = idx;
	addr.flags = 0;
	addr.desc_user_addr = pointer_to_uword (vring->desc);
	addr.avail_user_addr = pointer_to_uword (vring->avail);
	addr.used_user_addr = pointer_to_uword (vring->used);
	_IOCTL (vif->fd, VHOST_SET_VRING_ADDR, &addr);

	file.index = idx;
	file.fd = vring->kick_fd;
	_IOCTL (vif->fd, VHOST_SET_VRING_KICK, &file);
	file.fd = vring->call_fd;
	_IOCTL (vif->fd, VHOST_SET_VRING_CALL, &file);
	file.fd = vif->tap_fd;
	_IOCTL (vif->fd, VHOST_NET_SET_BACKEND, &file);

	error:
	return err;
	}

	inline void
	virtio_free_rx_buffers (vlib_main_t * vm, virtio_vring_t * vring)
	{
	u16 used = vring->desc_in_use;
	u16 last = vring->last_used_idx;
	u16 mask = vring->size - 1;

	while (used)
	{
	vlib_buffer_free (vm, &vring->buffers[last & mask], 1);
	last++;
	used--;
	}
	}

	clib_error_t *
	virtio_vring_free (vlib_main_t * vm, virtio_if_t * vif, u32 idx)
	{
	virtio_vring_t *vring = vec_elt_at_index (vif->vrings, idx);

	clib_file_del_by_index (&file_main, vring->call_file_index);
	close (vring->kick_fd);
	close (vring->call_fd);
	if (vring->used)
	{
	if ((idx & 1) == 1)
	virtio_free_used_desc (vm, vring);
	else
	virtio_free_rx_buffers (vm, vring);
	clib_mem_free (vring->used);
	}
	if (vring->desc)
	clib_mem_free (vring->desc);
	if (vring->avail)
	clib_mem_free (vring->avail);
	if (vring->queue_id % 2)
	{
	vlib_buffer_free_no_next (vm, vring->indirect_buffers, vring->size);
	}
	vec_free (vring->buffers);
	vec_free (vring->indirect_buffers);
	return 0;
	}

	inline void
	virtio_set_net_hdr_size (virtio_if_t * vif)
	{
	if (vif->features & VIRTIO_FEATURE (VIRTIO_NET_F_MRG_RXBUF) \|\|
	vif->features & VIRTIO_FEATURE (VIRTIO_F_VERSION_1))
	vif->virtio_net_hdr_sz = sizeof (struct virtio_net_hdr_v1);
	else
	vif->virtio_net_hdr_sz = sizeof (struct virtio_net_hdr);
	}

	inline void
	virtio_show (vlib_main_t * vm, u32 * hw_if_indices, u8 show_descr, u32 type)
	{
	u32 i, j, hw_if_index;
	virtio_if_t *vif;
	vnet_main_t *vnm = &vnet_main;
	virtio_main_t *mm = &virtio_main;
	virtio_vring_t *vring;
	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_features
	#undef _
	{.str = NULL}
	};

	struct feat_struct *flag_entry;
	static struct feat_struct flags_array[] = {
	#define _(b,e,s) { .bit = b, .str = s, },
	foreach_virtio_if_flag
	#undef _
	{.str = NULL}
	};

	if (!hw_if_indices)
	return;

	for (hw_if_index = 0; hw_if_index < vec_len (hw_if_indices); hw_if_index++)
	{
	vnet_hw_interface_t *hi =
	vnet_get_hw_interface (vnm, hw_if_indices[hw_if_index]);
	vif = pool_elt_at_index (mm->interfaces, hi->dev_instance);
	if (vif->type != type)
	continue;
	vlib_cli_output (vm, "Interface: %U (ifindex %d)",
	format_vnet_hw_if_index_name, vnm,
	hw_if_indices[hw_if_index], vif->hw_if_index);
	if (type == VIRTIO_IF_TYPE_PCI)
	{
	vlib_cli_output (vm, " PCI Address: %U", format_vlib_pci_addr,
	&vif->pci_addr);
	}
	if (type == VIRTIO_IF_TYPE_TAP)
	{
	if (vif->host_if_name)
	vlib_cli_output (vm, " name \"%s\"", vif->host_if_name);
	if (vif->net_ns)
	vlib_cli_output (vm, " host-ns \"%s\"", vif->net_ns);
	vlib_cli_output (vm, " fd %d", vif->fd);
	vlib_cli_output (vm, " tap-fd %d", vif->tap_fd);
	}
	vlib_cli_output (vm, " Mac Address: %U", format_ethernet_address,
	vif->mac_addr);
	vlib_cli_output (vm, " Device instance: %u", vif->dev_instance);
	vlib_cli_output (vm, " flags 0x%x", vif->flags);
	flag_entry = (struct feat_struct *) &flags_array;
	while (flag_entry->str)
	{
	if (vif->flags & (1ULL << flag_entry->bit))
	vlib_cli_output (vm, " %s (%d)", flag_entry->str,
	flag_entry->bit);
	flag_entry++;
	}
	if (type == VIRTIO_IF_TYPE_PCI)
	{
	device_status (vm, vif);
	}
	vlib_cli_output (vm, " features 0x%lx", vif->features);
	feat_entry = (struct feat_struct *) &feat_array;
	while (feat_entry->str)
	{
	if (vif->features & (1ULL << feat_entry->bit))
	vlib_cli_output (vm, " %s (%d)", feat_entry->str,
	feat_entry->bit);
	feat_entry++;
	}
	vlib_cli_output (vm, " remote-features 0x%lx", vif->remote_features);
	feat_entry = (struct feat_struct *) &feat_array;
	while (feat_entry->str)
	{
	if (vif->remote_features & (1ULL << feat_entry->bit))
	vlib_cli_output (vm, " %s (%d)", feat_entry->str,
	feat_entry->bit);
	feat_entry++;
	}
	vec_foreach_index (i, vif->vrings)
	{
	// RX = 0, TX = 1
	vring = vec_elt_at_index (vif->vrings, i);
	vlib_cli_output (vm, " Virtqueue (%s)", (i & 1) ? "TX" : "RX");
	vlib_cli_output (vm,
	" qsz %d, last_used_idx %d, desc_next %d, desc_in_use %d",
	vring->size, vring->last_used_idx, vring->desc_next,
	vring->desc_in_use);
	vlib_cli_output (vm,
	" avail.flags 0x%x avail.idx %d used.flags 0x%x used.idx %d",
	vring->avail->flags, vring->avail->idx,
	vring->used->flags, vring->used->idx);
	if (type == VIRTIO_IF_TYPE_TAP)
	{
	vlib_cli_output (vm, " kickfd %d, callfd %d", vring->kick_fd,
	vring->call_fd);
	}
	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");
	vring = vif->vrings;
	for (j = 0; j < vring->size; j++)
	{
	struct vring_desc *desc = &vring->desc[j];
	vlib_cli_output (vm,
	" %-5d 0x%016lx %-5d 0x%04x %-5d 0x%016lx\n",
	j, desc->addr,
	desc->len,
	desc->flags, desc->next, desc->addr);
	}
	}
	}
	}

	}

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/