2 *------------------------------------------------------------------
5 * Copyright (c) 2014-2018 Cisco and/or its affiliates.
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at:
10 * http://www.apache.org/licenses/LICENSE-2.0
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 *------------------------------------------------------------------
20 #include <fcntl.h> /* for open */
21 #include <sys/ioctl.h>
22 #include <sys/socket.h>
25 #include <sys/types.h>
26 #include <sys/uio.h> /* for iovec */
27 #include <netinet/in.h>
30 #include <linux/if_arp.h>
31 #include <linux/if_tun.h>
33 #include <vlib/vlib.h>
34 #include <vlib/unix/unix.h>
36 #include <vnet/ip/ip.h>
38 #include <vnet/ethernet/ethernet.h>
39 #include <vnet/devices/devices.h>
40 #include <vnet/feature/feature.h>
42 #include <vnet/devices/virtio/vhost_user.h>
43 #include <vnet/devices/virtio/vhost_user_inline.h>
46 * When an RX queue is down but active, received packets
47 * must be discarded. This value controls up to how many
48 * packets will be discarded during each round.
50 #define VHOST_USER_DOWN_DISCARD_COUNT 256
53 * When the number of available buffers gets under this threshold,
54 * RX node will start discarding packets.
56 #define VHOST_USER_RX_BUFFER_STARVATION 32
59 * On the receive side, the host should free descriptors as soon
60 * as possible in order to avoid TX drop in the VM.
61 * This value controls the number of copy operations that are stacked
62 * before copy is done for all and descriptors are given back to
64 * The value 64 was obtained by testing (48 and 128 were not as good).
66 #define VHOST_USER_RX_COPY_THRESHOLD 64
68 vlib_node_registration_t vhost_user_input_node;
70 #define foreach_vhost_user_input_func_error \
71 _(NO_ERROR, "no error") \
72 _(NO_BUFFER, "no available buffer") \
73 _(MMAP_FAIL, "mmap failure") \
74 _(INDIRECT_OVERFLOW, "indirect descriptor overflows table") \
75 _(UNDERSIZED_FRAME, "undersized ethernet frame received (< 14 bytes)") \
76 _(FULL_RX_QUEUE, "full rx queue (possible driver tx drop)")
80 #define _(f,s) VHOST_USER_INPUT_FUNC_ERROR_##f,
81 foreach_vhost_user_input_func_error
83 VHOST_USER_INPUT_FUNC_N_ERROR,
84 } vhost_user_input_func_error_t;
86 static __clib_unused char *vhost_user_input_func_error_strings[] = {
88 foreach_vhost_user_input_func_error
92 static_always_inline void
93 vhost_user_rx_trace (vhost_trace_t * t,
94 vhost_user_intf_t * vui, u16 qid,
95 vlib_buffer_t * b, vhost_user_vring_t * txvq,
98 vhost_user_main_t *vum = &vhost_user_main;
99 u32 desc_current = txvq->avail->ring[last_avail_idx & txvq->qsz_mask];
100 vring_desc_t *hdr_desc = 0;
101 virtio_net_hdr_mrg_rxbuf_t *hdr;
104 clib_memset (t, 0, sizeof (*t));
105 t->device_index = vui - vum->vhost_user_interfaces;
108 hdr_desc = &txvq->desc[desc_current];
109 if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT)
111 t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_INDIRECT;
112 /* Header is the first here */
113 hdr_desc = map_guest_mem (vui, txvq->desc[desc_current].addr, &hint);
115 if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT)
117 t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_SIMPLE_CHAINED;
119 if (!(txvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT) &&
120 !(txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT))
122 t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_SINGLE_DESC;
125 t->first_desc_len = hdr_desc ? hdr_desc->len : 0;
127 if (!hdr_desc || !(hdr = map_guest_mem (vui, hdr_desc->addr, &hint)))
129 t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_MAP_ERROR;
133 u32 len = vui->virtio_net_hdr_sz;
134 memcpy (&t->hdr, hdr, len > hdr_desc->len ? hdr_desc->len : len);
138 static_always_inline u32
139 vhost_user_input_copy (vhost_user_intf_t * vui, vhost_copy_t * cpy,
140 u16 copy_len, u32 * map_hint)
142 void *src0, *src1, *src2, *src3;
143 if (PREDICT_TRUE (copy_len >= 4))
145 if (PREDICT_FALSE (!(src2 = map_guest_mem (vui, cpy[0].src, map_hint))))
147 if (PREDICT_FALSE (!(src3 = map_guest_mem (vui, cpy[1].src, map_hint))))
150 while (PREDICT_TRUE (copy_len >= 4))
156 (!(src2 = map_guest_mem (vui, cpy[2].src, map_hint))))
159 (!(src3 = map_guest_mem (vui, cpy[3].src, map_hint))))
162 CLIB_PREFETCH (src2, 64, LOAD);
163 CLIB_PREFETCH (src3, 64, LOAD);
165 clib_memcpy_fast ((void *) cpy[0].dst, src0, cpy[0].len);
166 clib_memcpy_fast ((void *) cpy[1].dst, src1, cpy[1].len);
173 if (PREDICT_FALSE (!(src0 = map_guest_mem (vui, cpy->src, map_hint))))
175 clib_memcpy_fast ((void *) cpy->dst, src0, cpy->len);
183 * Try to discard packets from the tx ring (VPP RX path).
184 * Returns the number of discarded packets.
186 static_always_inline u32
187 vhost_user_rx_discard_packet (vlib_main_t * vm,
188 vhost_user_intf_t * vui,
189 vhost_user_vring_t * txvq, u32 discard_max)
192 * On the RX side, each packet corresponds to one descriptor
193 * (it is the same whether it is a shallow descriptor, chained, or indirect).
194 * Therefore, discarding a packet is like discarding a descriptor.
196 u32 discarded_packets = 0;
197 u32 avail_idx = txvq->avail->idx;
198 u16 mask = txvq->qsz_mask;
199 u16 last_avail_idx = txvq->last_avail_idx;
200 u16 last_used_idx = txvq->last_used_idx;
201 while (discarded_packets != discard_max)
203 if (avail_idx == txvq->last_avail_idx)
206 u16 desc_chain_head = txvq->avail->ring[last_avail_idx & mask];
208 txvq->used->ring[last_used_idx & mask].id = desc_chain_head;
209 txvq->used->ring[last_used_idx & mask].len = 0;
210 vhost_user_log_dirty_ring (vui, txvq, ring[last_used_idx & mask]);
216 txvq->last_avail_idx = last_avail_idx;
217 txvq->last_used_idx = last_used_idx;
218 CLIB_MEMORY_STORE_BARRIER ();
219 txvq->used->idx = txvq->last_used_idx;
220 vhost_user_log_dirty_ring (vui, txvq, idx);
221 return discarded_packets;
225 * In case of overflow, we need to rewind the array of allocated buffers.
227 static_always_inline void
228 vhost_user_input_rewind_buffers (vlib_main_t * vm,
229 vhost_cpu_t * cpu, vlib_buffer_t * b_head)
231 u32 bi_current = cpu->rx_buffers[cpu->rx_buffers_len];
232 vlib_buffer_t *b_current = vlib_get_buffer (vm, bi_current);
233 b_current->current_length = 0;
234 b_current->flags = 0;
235 while (b_current != b_head)
237 cpu->rx_buffers_len++;
238 bi_current = cpu->rx_buffers[cpu->rx_buffers_len];
239 b_current = vlib_get_buffer (vm, bi_current);
240 b_current->current_length = 0;
241 b_current->flags = 0;
243 cpu->rx_buffers_len++;
246 static_always_inline u32
247 vhost_user_if_input (vlib_main_t * vm,
248 vhost_user_main_t * vum,
249 vhost_user_intf_t * vui,
250 u16 qid, vlib_node_runtime_t * node,
251 vnet_hw_interface_rx_mode mode)
253 vhost_user_vring_t *txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)];
254 vnet_feature_main_t *fm = &feature_main;
255 u16 n_rx_packets = 0;
258 u32 n_left_to_next, *to_next;
259 u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
260 u32 n_trace = vlib_get_trace_count (vm, node);
261 u32 buffer_data_size = vlib_buffer_get_default_data_size (vm);
263 vhost_cpu_t *cpu = &vum->cpus[vm->thread_index];
265 u8 feature_arc_idx = fm->device_input_feature_arc_index;
266 u32 current_config_index = ~(u32) 0;
267 u16 mask = txvq->qsz_mask;
269 /* The descriptor table is not ready yet */
270 if (PREDICT_FALSE (txvq->avail == 0))
274 /* do we have pending interrupts ? */
275 vhost_user_vring_t *rxvq = &vui->vrings[VHOST_VRING_IDX_RX (qid)];
276 f64 now = vlib_time_now (vm);
278 if ((txvq->n_since_last_int) && (txvq->int_deadline < now))
279 vhost_user_send_call (vm, txvq);
281 if ((rxvq->n_since_last_int) && (rxvq->int_deadline < now))
282 vhost_user_send_call (vm, rxvq);
286 * For adaptive mode, it is optimized to reduce interrupts.
287 * If the scheduler switches the input node to polling due
288 * to burst of traffic, we tell the driver no interrupt.
289 * When the traffic subsides, the scheduler switches the node back to
290 * interrupt mode. We must tell the driver we want interrupt.
292 if (PREDICT_FALSE (mode == VNET_HW_INTERFACE_RX_MODE_ADAPTIVE))
295 VLIB_NODE_FLAG_SWITCH_FROM_POLLING_TO_INTERRUPT_MODE) ||
297 VLIB_NODE_FLAG_SWITCH_FROM_INTERRUPT_TO_POLLING_MODE))
298 /* Tell driver we want notification */
299 txvq->used->flags = 0;
301 /* Tell driver we don't want notification */
302 txvq->used->flags = VRING_USED_F_NO_NOTIFY;
305 if (PREDICT_FALSE (txvq->avail->flags & 0xFFFE))
308 n_left = (u16) (txvq->avail->idx - txvq->last_avail_idx);
311 if (PREDICT_FALSE (n_left == 0))
314 if (PREDICT_FALSE (!vui->admin_up || !(txvq->enabled)))
317 * Discard input packet if interface is admin down or vring is not
319 * "For example, for a networking device, in the disabled state
320 * client must not supply any new RX packets, but must process
321 * and discard any TX packets."
323 vhost_user_rx_discard_packet (vm, vui, txvq,
324 VHOST_USER_DOWN_DISCARD_COUNT);
328 if (PREDICT_FALSE (n_left == (mask + 1)))
331 * Informational error logging when VPP is not
332 * receiving packets fast enough.
334 vlib_error_count (vm, node->node_index,
335 VHOST_USER_INPUT_FUNC_ERROR_FULL_RX_QUEUE, 1);
338 if (n_left > VLIB_FRAME_SIZE)
339 n_left = VLIB_FRAME_SIZE;
342 * For small packets (<2kB), we will not need more than one vlib buffer
343 * per packet. In case packets are bigger, we will just yeld at some point
344 * in the loop and come back later. This is not an issue as for big packet,
345 * processing cost really comes from the memory copy.
346 * The assumption is that big packets will fit in 40 buffers.
348 if (PREDICT_FALSE (cpu->rx_buffers_len < n_left + 1 ||
349 cpu->rx_buffers_len < 40))
351 u32 curr_len = cpu->rx_buffers_len;
352 cpu->rx_buffers_len +=
353 vlib_buffer_alloc (vm, cpu->rx_buffers + curr_len,
354 VHOST_USER_RX_BUFFERS_N - curr_len);
357 (cpu->rx_buffers_len < VHOST_USER_RX_BUFFER_STARVATION))
359 /* In case of buffer starvation, discard some packets from the queue
361 * We keep doing best effort for the remaining packets. */
362 u32 flush = (n_left + 1 > cpu->rx_buffers_len) ?
363 n_left + 1 - cpu->rx_buffers_len : 1;
364 flush = vhost_user_rx_discard_packet (vm, vui, txvq, flush);
367 vlib_increment_simple_counter (vnet_main.
368 interface_main.sw_if_counters +
369 VNET_INTERFACE_COUNTER_DROP,
370 vm->thread_index, vui->sw_if_index,
373 vlib_error_count (vm, vhost_user_input_node.index,
374 VHOST_USER_INPUT_FUNC_ERROR_NO_BUFFER, flush);
378 if (PREDICT_FALSE (vnet_have_features (feature_arc_idx, vui->sw_if_index)))
380 vnet_feature_config_main_t *cm;
381 cm = &fm->feature_config_mains[feature_arc_idx];
382 current_config_index = vec_elt (cm->config_index_by_sw_if_index,
384 vnet_get_config_data (&cm->config_main, ¤t_config_index,
388 u16 last_avail_idx = txvq->last_avail_idx;
389 u16 last_used_idx = txvq->last_used_idx;
391 vlib_get_new_next_frame (vm, node, next_index, to_next, n_left_to_next);
393 if (next_index == VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT)
395 /* give some hints to ethernet-input */
396 vlib_next_frame_t *nf;
398 ethernet_input_frame_t *ef;
399 nf = vlib_node_runtime_get_next_frame (vm, node, next_index);
400 f = vlib_get_frame (vm, nf->frame_index);
401 f->flags = ETH_INPUT_FRAME_F_SINGLE_SW_IF_IDX;
403 ef = vlib_frame_scalar_args (f);
404 ef->sw_if_index = vui->sw_if_index;
405 ef->hw_if_index = vui->hw_if_index;
410 vlib_buffer_t *b_head, *b_current;
413 u32 desc_data_offset;
414 vring_desc_t *desc_table = txvq->desc;
416 if (PREDICT_FALSE (cpu->rx_buffers_len <= 1))
418 /* Not enough rx_buffers
419 * Note: We yeld on 1 so we don't need to do an additional
420 * check for the next buffer prefetch.
426 desc_current = txvq->avail->ring[last_avail_idx & mask];
427 cpu->rx_buffers_len--;
428 bi_current = cpu->rx_buffers[cpu->rx_buffers_len];
429 b_head = b_current = vlib_get_buffer (vm, bi_current);
430 to_next[0] = bi_current; //We do that now so we can forget about bi_current
434 vlib_prefetch_buffer_with_index
435 (vm, cpu->rx_buffers[cpu->rx_buffers_len - 1], LOAD);
437 /* Just preset the used descriptor id and length for later */
438 txvq->used->ring[last_used_idx & mask].id = desc_current;
439 txvq->used->ring[last_used_idx & mask].len = 0;
440 vhost_user_log_dirty_ring (vui, txvq, ring[last_used_idx & mask]);
442 /* The buffer should already be initialized */
443 b_head->total_length_not_including_first_buffer = 0;
444 b_head->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
446 if (PREDICT_FALSE (n_trace))
448 //TODO: next_index is not exactly known at that point
449 vlib_trace_buffer (vm, node, next_index, b_head,
450 /* follow_chain */ 0);
452 vlib_add_trace (vm, node, b_head, sizeof (t0[0]));
453 vhost_user_rx_trace (t0, vui, qid, b_head, txvq, last_avail_idx);
455 vlib_set_trace_count (vm, node, n_trace);
458 /* This depends on the setup but is very consistent
459 * So I think the CPU branch predictor will make a pretty good job
460 * at optimizing the decision. */
461 if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT)
463 desc_table = map_guest_mem (vui, txvq->desc[desc_current].addr,
466 if (PREDICT_FALSE (desc_table == 0))
468 vlib_error_count (vm, node->node_index,
469 VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL, 1);
474 if (PREDICT_TRUE (vui->is_any_layout) ||
475 (!(desc_table[desc_current].flags & VIRTQ_DESC_F_NEXT)))
477 /* ANYLAYOUT or single buffer */
478 desc_data_offset = vui->virtio_net_hdr_sz;
482 /* CSR case without ANYLAYOUT, skip 1st buffer */
483 desc_data_offset = desc_table[desc_current].len;
488 /* Get more input if necessary. Or end of packet. */
489 if (desc_data_offset == desc_table[desc_current].len)
491 if (PREDICT_FALSE (desc_table[desc_current].flags &
494 desc_current = desc_table[desc_current].next;
495 desc_data_offset = 0;
503 /* Get more output if necessary. Or end of packet. */
504 if (PREDICT_FALSE (b_current->current_length == buffer_data_size))
506 if (PREDICT_FALSE (cpu->rx_buffers_len == 0))
508 /* Cancel speculation */
513 * Checking if there are some left buffers.
514 * If not, just rewind the used buffers and stop.
515 * Note: Scheduled copies are not cancelled. This is
516 * not an issue as they would still be valid. Useless,
519 vhost_user_input_rewind_buffers (vm, cpu, b_head);
524 /* Get next output */
525 cpu->rx_buffers_len--;
526 u32 bi_next = cpu->rx_buffers[cpu->rx_buffers_len];
527 b_current->next_buffer = bi_next;
528 b_current->flags |= VLIB_BUFFER_NEXT_PRESENT;
529 bi_current = bi_next;
530 b_current = vlib_get_buffer (vm, bi_current);
533 /* Prepare a copy order executed later for the data */
534 vhost_copy_t *cpy = &cpu->copy[copy_len];
536 u32 desc_data_l = desc_table[desc_current].len - desc_data_offset;
537 cpy->len = buffer_data_size - b_current->current_length;
538 cpy->len = (cpy->len > desc_data_l) ? desc_data_l : cpy->len;
539 cpy->dst = (uword) (vlib_buffer_get_current (b_current) +
540 b_current->current_length);
541 cpy->src = desc_table[desc_current].addr + desc_data_offset;
543 desc_data_offset += cpy->len;
545 b_current->current_length += cpy->len;
546 b_head->total_length_not_including_first_buffer += cpy->len;
551 n_rx_bytes += b_head->total_length_not_including_first_buffer;
554 b_head->total_length_not_including_first_buffer -=
555 b_head->current_length;
557 /* consume the descriptor and return it as used */
561 VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b_head);
563 vnet_buffer (b_head)->sw_if_index[VLIB_RX] = vui->sw_if_index;
564 vnet_buffer (b_head)->sw_if_index[VLIB_TX] = (u32) ~ 0;
567 if (current_config_index != ~(u32) 0)
569 b_head->current_config_index = current_config_index;
570 vnet_buffer (b_head)->feature_arc_index = feature_arc_idx;
576 * Although separating memory copies from virtio ring parsing
577 * is beneficial, we can offer to perform the copies from time
578 * to time in order to free some space in the ring.
580 if (PREDICT_FALSE (copy_len >= VHOST_USER_RX_COPY_THRESHOLD))
582 if (PREDICT_FALSE (vhost_user_input_copy (vui, cpu->copy,
583 copy_len, &map_hint)))
585 vlib_error_count (vm, node->node_index,
586 VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL, 1);
590 /* give buffers back to driver */
591 CLIB_MEMORY_STORE_BARRIER ();
592 txvq->used->idx = last_used_idx;
593 vhost_user_log_dirty_ring (vui, txvq, idx);
597 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
599 txvq->last_used_idx = last_used_idx;
600 txvq->last_avail_idx = last_avail_idx;
602 /* Do the memory copies */
603 if (PREDICT_FALSE (vhost_user_input_copy (vui, cpu->copy, copy_len,
606 vlib_error_count (vm, node->node_index,
607 VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL, 1);
610 /* give buffers back to driver */
611 CLIB_MEMORY_STORE_BARRIER ();
612 txvq->used->idx = txvq->last_used_idx;
613 vhost_user_log_dirty_ring (vui, txvq, idx);
615 /* interrupt (call) handling */
616 if ((txvq->callfd_idx != ~0) &&
617 !(txvq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
619 txvq->n_since_last_int += n_rx_packets;
621 if (txvq->n_since_last_int > vum->coalesce_frames)
622 vhost_user_send_call (vm, txvq);
625 /* increase rx counters */
626 vlib_increment_combined_counter
627 (vnet_main.interface_main.combined_sw_if_counters
628 + VNET_INTERFACE_COUNTER_RX, vm->thread_index, vui->sw_if_index,
629 n_rx_packets, n_rx_bytes);
631 vnet_device_increment_rx_packets (vm->thread_index, n_rx_packets);
637 VLIB_NODE_FN (vhost_user_input_node) (vlib_main_t * vm,
638 vlib_node_runtime_t * node,
639 vlib_frame_t * frame)
641 vhost_user_main_t *vum = &vhost_user_main;
642 uword n_rx_packets = 0;
643 vhost_user_intf_t *vui;
644 vnet_device_input_runtime_t *rt =
645 (vnet_device_input_runtime_t *) node->runtime_data;
646 vnet_device_and_queue_t *dq;
648 vec_foreach (dq, rt->devices_and_queues)
650 if ((node->state == VLIB_NODE_STATE_POLLING) ||
651 clib_atomic_swap_acq_n (&dq->interrupt_pending, 0))
654 pool_elt_at_index (vum->vhost_user_interfaces, dq->dev_instance);
655 n_rx_packets += vhost_user_if_input (vm, vum, vui, dq->queue_id, node,
664 VLIB_REGISTER_NODE (vhost_user_input_node) = {
665 .type = VLIB_NODE_TYPE_INPUT,
666 .name = "vhost-user-input",
667 .sibling_of = "device-input",
669 /* Will be enabled if/when hardware is detected. */
670 .state = VLIB_NODE_STATE_DISABLED,
672 .format_buffer = format_ethernet_header_with_length,
673 .format_trace = format_vhost_trace,
675 .n_errors = VHOST_USER_INPUT_FUNC_N_ERROR,
676 .error_strings = vhost_user_input_func_error_strings,
681 * fd.io coding-style-patch-verification: ON
684 * eval: (c-set-style "gnu")