virtio: fast TAP interfaces with vhost-net backend
Change-Id: Ided667356d5c6fb9648eb34685aabd6b16a598b7
Signed-off-by: Damjan Marion <damarion@cisco.com>
Signed-off-by: Steven Luong <sluong@cisco.com>
diff --git a/src/vnet/devices/virtio/node.c b/src/vnet/devices/virtio/node.c
new file mode 100644
index 0000000..f746ada
--- /dev/null
+++ b/src/vnet/devices/virtio/node.c
@@ -0,0 +1,302 @@
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2016 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/unix/unix.h>
+#include <vnet/ethernet/ethernet.h>
+#include <vnet/devices/devices.h>
+#include <vnet/feature/feature.h>
+#include <vnet/devices/virtio/virtio.h>
+
+
+#define foreach_virtio_input_error \
+ _(UNKNOWN, "unknown")
+
+typedef enum
+{
+#define _(f,s) TAP_INPUT_ERROR_##f,
+ foreach_virtio_input_error
+#undef _
+ TAP_INPUT_N_ERROR,
+} virtio_input_error_t;
+
+static char *virtio_input_error_strings[] = {
+#define _(n,s) s,
+ foreach_virtio_input_error
+#undef _
+};
+
+typedef struct
+{
+ u32 next_index;
+ u32 hw_if_index;
+ u16 ring;
+ u16 len;
+ struct virtio_net_hdr_v1 hdr;
+} virtio_input_trace_t;
+
+static u8 *
+format_virtio_input_trace (u8 * s, va_list * args)
+{
+ CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+ CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+ virtio_input_trace_t *t = va_arg (*args, virtio_input_trace_t *);
+ u32 indent = format_get_indent (s);
+
+ s = format (s, "virtio: hw_if_index %d next-index %d vring %u len %u",
+ t->hw_if_index, t->next_index, t->ring, t->len);
+ s = format (s, "\n%Uhdr: flags 0x%02x gso_type 0x%02x hdr_len %u "
+ "gso_size %u csum_start %u csum_offset %u num_buffers %u",
+ format_white_space, indent + 2,
+ t->hdr.flags, t->hdr.gso_type, t->hdr.hdr_len, t->hdr.gso_size,
+ t->hdr.csum_start, t->hdr.csum_offset, t->hdr.num_buffers);
+ return s;
+}
+
+static_always_inline void
+virtio_refill_vring (vlib_main_t * vm, virtio_vring_t * vring)
+{
+ const int hdr_sz = sizeof (struct virtio_net_hdr_v1);
+ u16 used, next, avail, n_slots, n_alloc;
+ u16 sz = vring->size;
+ u16 mask = sz - 1;
+ int i;
+
+ used = vring->desc_in_use;
+
+ if (sz - used < sz / 8)
+ return;
+
+ n_slots = sz - used;
+ next = vring->desc_next;
+ avail = vring->avail->idx;
+ n_alloc = vlib_buffer_alloc (vm, &vring->buffers[next], n_slots);
+
+ if (PREDICT_FALSE (n_alloc < n_slots))
+ n_slots = n_alloc;
+
+ i = next + n_slots - sz;
+ if (PREDICT_FALSE (i > 0))
+ clib_memcpy (vring->buffers, &vring->buffers[sz], i * sizeof (u32));
+
+ while (n_slots)
+ {
+ struct vring_desc *d = &vring->desc[next];;
+ vlib_buffer_t *b = vlib_get_buffer (vm, vring->buffers[next]);
+ d->addr = pointer_to_uword (vlib_buffer_get_current (b)) - hdr_sz;
+ d->len = VLIB_BUFFER_DATA_SIZE + hdr_sz;
+ d->flags = VRING_DESC_F_WRITE;
+ vring->avail->ring[avail & mask] = next;
+ avail++;
+ next = (next + 1) & mask;
+ n_slots--;
+ used++;
+ }
+ CLIB_MEMORY_STORE_BARRIER ();
+ vring->avail->idx = avail;
+ vring->desc_next = next;
+ vring->desc_in_use = used;
+
+ if ((vring->used->flags & VIRTIO_RING_FLAG_MASK_INT) == 0)
+ {
+ u64 b = 1;
+ CLIB_UNUSED (int r) = write (vring->kick_fd, &b, sizeof (b));
+ }
+}
+
+static_always_inline uword
+virtio_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
+ vlib_frame_t * frame, virtio_if_t * vif, u16 qid)
+{
+ vnet_main_t *vnm = vnet_get_main ();
+ u32 thread_index = vlib_get_thread_index ();
+ uword n_trace = vlib_get_trace_count (vm, node);
+ virtio_vring_t *vring = vec_elt_at_index (vif->vrings, 0);
+ u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
+ const int hdr_sz = sizeof (struct virtio_net_hdr_v1);
+ u32 *to_next = 0;
+ u32 n_rx_packets = 0;
+ u32 n_rx_bytes = 0;
+ u16 mask = vring->size - 1;
+ u16 last = vring->last_used_idx;
+ u16 n_left = vring->used->idx - last;
+
+ if (n_left == 0)
+ goto refill;
+
+ while (n_left)
+ {
+ u32 n_left_to_next;
+ u32 next0 = next_index;
+ vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+ while (n_left && n_left_to_next)
+ {
+ u16 num_buffers;
+ struct vring_used_elem *e = &vring->used->ring[last & mask];
+ struct virtio_net_hdr_v1 *hdr;
+ u16 slot = e->id;
+ u16 len = e->len - hdr_sz;
+ u32 bi0 = vring->buffers[slot];
+ vlib_buffer_t *b0 = vlib_get_buffer (vm, bi0);
+ hdr = vlib_buffer_get_current (b0) - hdr_sz;
+ num_buffers = hdr->num_buffers;
+
+ b0->current_data = 0;
+ b0->current_length = len;
+ b0->total_length_not_including_first_buffer = 0;
+ b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
+ vnet_buffer (b0)->sw_if_index[VLIB_RX] = vif->sw_if_index;
+ vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+
+ /* if multisegment packet */
+ if (PREDICT_FALSE (num_buffers > 1))
+ {
+ vlib_buffer_t *pb, *cb;
+ pb = b0;
+ while (num_buffers > 1)
+ {
+ last++;
+ e = &vring->used->ring[last & mask];
+ u32 cbi = vring->buffers[e->id];
+ cb = vlib_get_buffer (vm, cbi);
+
+ /* current buffer */
+ cb->current_data = -hdr_sz;
+ cb->current_length = e->len;
+
+ /* previous buffer */
+ pb->next_buffer = cbi;
+ pb->flags |= VLIB_BUFFER_NEXT_PRESENT;
+
+ /* first buffer */
+ b0->total_length_not_including_first_buffer += e->len;
+
+ pb = cb;
+ vring->desc_in_use--;
+ num_buffers--;
+ n_left--;
+ }
+ }
+
+ if (PREDICT_FALSE (vif->per_interface_next_index != ~0))
+ next0 = vif->per_interface_next_index;
+ else
+ /* redirect if feature path enabled */
+ vnet_feature_start_device_input_x1 (vif->sw_if_index, &next0, b0);
+ /* trace */
+ VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);
+
+ if (PREDICT_FALSE (n_trace > 0))
+ {
+ virtio_input_trace_t *tr;
+ vlib_trace_buffer (vm, node, next0, b0,
+ /* follow_chain */ 0);
+ vlib_set_trace_count (vm, node, --n_trace);
+ tr = vlib_add_trace (vm, node, b0, sizeof (*tr));
+ tr->next_index = next0;
+ tr->hw_if_index = vif->hw_if_index;
+ tr->len = len;
+ clib_memcpy (&tr->hdr, hdr, hdr_sz);
+ }
+
+ /* enqueue buffer */
+ to_next[0] = bi0;
+ vring->desc_in_use--;
+ to_next += 1;
+ n_left_to_next--;
+ n_left--;
+ last++;
+
+ /* enqueue */
+ vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
+ n_left_to_next, bi0, next0);
+
+ /* next packet */
+ n_rx_packets++;
+ n_rx_bytes += len;
+ }
+ vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+ }
+ vring->last_used_idx = last;
+
+ vlib_increment_combined_counter (vnm->interface_main.combined_sw_if_counters
+ + VNET_INTERFACE_COUNTER_RX, thread_index,
+ vif->hw_if_index, n_rx_packets,
+ n_rx_bytes);
+
+refill:
+ virtio_refill_vring (vm, vring);
+
+ return n_rx_packets;
+}
+
+static uword
+virtio_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
+ vlib_frame_t * frame)
+{
+ u32 n_rx = 0;
+ virtio_main_t *nm = &virtio_main;
+ vnet_device_input_runtime_t *rt = (void *) node->runtime_data;
+ vnet_device_and_queue_t *dq;
+
+ foreach_device_and_queue (dq, rt->devices_and_queues)
+ {
+ virtio_if_t *mif;
+ mif = vec_elt_at_index (nm->interfaces, dq->dev_instance);
+ if (mif->flags & VIRTIO_IF_FLAG_ADMIN_UP)
+ {
+ n_rx += virtio_device_input_inline (vm, node, frame, mif,
+ dq->queue_id);
+ }
+ }
+
+ return n_rx;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (virtio_input_node) = {
+ .function = virtio_input_fn,
+ .name = "virtio-input",
+ .sibling_of = "device-input",
+ .format_trace = format_virtio_input_trace,
+ .type = VLIB_NODE_TYPE_INPUT,
+ .state = VLIB_NODE_STATE_INTERRUPT,
+ .n_errors = TAP_INPUT_N_ERROR,
+ .error_strings = virtio_input_error_strings,
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (virtio_input_node, virtio_input_fn)
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */