xref: /dpdk/lib/vhost/virtio_net.c (revision 7cc8ef9cf4e9d1f3b1c16daea706f9f433968c61)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2016 Intel Corporation
3  */
4 
5 #include <stdint.h>
6 #include <stdbool.h>
7 #include <linux/virtio_net.h>
8 
9 #include <rte_mbuf.h>
10 #include <rte_memcpy.h>
11 #include <rte_net.h>
12 #include <rte_ether.h>
13 #include <rte_ip.h>
14 #include <rte_dmadev.h>
15 #include <rte_vhost.h>
16 #include <rte_tcp.h>
17 #include <rte_udp.h>
18 #include <rte_sctp.h>
19 #include <rte_arp.h>
20 #include <rte_spinlock.h>
21 #include <rte_malloc.h>
22 #include <rte_vhost_async.h>
23 
24 #include "iotlb.h"
25 #include "vhost.h"
26 
27 #define MAX_BATCH_LEN 256
28 
29 /* DMA device copy operation tracking array. */
30 struct async_dma_info dma_copy_track[RTE_DMADEV_DEFAULT_MAX];
31 
32 static  __rte_always_inline bool
33 rxvq_is_mergeable(struct virtio_net *dev)
34 {
35 	return dev->features & (1ULL << VIRTIO_NET_F_MRG_RXBUF);
36 }
37 
38 static  __rte_always_inline bool
39 virtio_net_is_inorder(struct virtio_net *dev)
40 {
41 	return dev->features & (1ULL << VIRTIO_F_IN_ORDER);
42 }
43 
44 static bool
45 is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
46 {
47 	return (is_tx ^ (idx & 1)) == 0 && idx < nr_vring;
48 }
49 
50 static __rte_always_inline int64_t
51 vhost_async_dma_transfer_one(struct virtio_net *dev, struct vhost_virtqueue *vq,
52 		int16_t dma_id, uint16_t vchan_id, uint16_t flag_idx,
53 		struct vhost_iov_iter *pkt)
54 {
55 	struct async_dma_vchan_info *dma_info = &dma_copy_track[dma_id].vchans[vchan_id];
56 	uint16_t ring_mask = dma_info->ring_mask;
57 	static bool vhost_async_dma_copy_log;
58 
59 
60 	struct vhost_iovec *iov = pkt->iov;
61 	int copy_idx = 0;
62 	uint32_t nr_segs = pkt->nr_segs;
63 	uint16_t i;
64 
65 	if (rte_dma_burst_capacity(dma_id, vchan_id) < nr_segs)
66 		return -1;
67 
68 	for (i = 0; i < nr_segs; i++) {
69 		copy_idx = rte_dma_copy(dma_id, vchan_id, (rte_iova_t)iov[i].src_addr,
70 				(rte_iova_t)iov[i].dst_addr, iov[i].len, RTE_DMA_OP_FLAG_LLC);
71 		/**
72 		 * Since all memory is pinned and DMA vChannel
73 		 * ring has enough space, failure should be a
74 		 * rare case. If failure happens, it means DMA
75 		 * device encounters serious errors; in this
76 		 * case, please stop async data-path and check
77 		 * what has happened to DMA device.
78 		 */
79 		if (unlikely(copy_idx < 0)) {
80 			if (!vhost_async_dma_copy_log) {
81 				VHOST_LOG_DATA(ERR, "(%s) DMA copy failed for channel %d:%u\n",
82 						dev->ifname, dma_id, vchan_id);
83 				vhost_async_dma_copy_log = true;
84 			}
85 			return -1;
86 		}
87 	}
88 
89 	/**
90 	 * Only store packet completion flag address in the last copy's
91 	 * slot, and other slots are set to NULL.
92 	 */
93 	dma_info->pkts_cmpl_flag_addr[copy_idx & ring_mask] = &vq->async->pkts_cmpl_flag[flag_idx];
94 
95 	return nr_segs;
96 }
97 
98 static __rte_always_inline uint16_t
99 vhost_async_dma_transfer(struct virtio_net *dev, struct vhost_virtqueue *vq,
100 		int16_t dma_id, uint16_t vchan_id, uint16_t head_idx,
101 		struct vhost_iov_iter *pkts, uint16_t nr_pkts)
102 {
103 	struct async_dma_vchan_info *dma_info = &dma_copy_track[dma_id].vchans[vchan_id];
104 	int64_t ret, nr_copies = 0;
105 	uint16_t pkt_idx;
106 
107 	rte_spinlock_lock(&dma_info->dma_lock);
108 
109 	for (pkt_idx = 0; pkt_idx < nr_pkts; pkt_idx++) {
110 		ret = vhost_async_dma_transfer_one(dev, vq, dma_id, vchan_id, head_idx,
111 				&pkts[pkt_idx]);
112 		if (unlikely(ret < 0))
113 			break;
114 
115 		nr_copies += ret;
116 		head_idx++;
117 		if (head_idx >= vq->size)
118 			head_idx -= vq->size;
119 	}
120 
121 	if (likely(nr_copies > 0))
122 		rte_dma_submit(dma_id, vchan_id);
123 
124 	rte_spinlock_unlock(&dma_info->dma_lock);
125 
126 	return pkt_idx;
127 }
128 
129 static __rte_always_inline uint16_t
130 vhost_async_dma_check_completed(struct virtio_net *dev, int16_t dma_id, uint16_t vchan_id,
131 		uint16_t max_pkts)
132 {
133 	struct async_dma_vchan_info *dma_info = &dma_copy_track[dma_id].vchans[vchan_id];
134 	uint16_t ring_mask = dma_info->ring_mask;
135 	uint16_t last_idx = 0;
136 	uint16_t nr_copies;
137 	uint16_t copy_idx;
138 	uint16_t i;
139 	bool has_error = false;
140 	static bool vhost_async_dma_complete_log;
141 
142 	rte_spinlock_lock(&dma_info->dma_lock);
143 
144 	/**
145 	 * Print error log for debugging, if DMA reports error during
146 	 * DMA transfer. We do not handle error in vhost level.
147 	 */
148 	nr_copies = rte_dma_completed(dma_id, vchan_id, max_pkts, &last_idx, &has_error);
149 	if (unlikely(!vhost_async_dma_complete_log && has_error)) {
150 		VHOST_LOG_DATA(ERR, "(%s) DMA completion failure on channel %d:%u\n", dev->ifname,
151 				dma_id, vchan_id);
152 		vhost_async_dma_complete_log = true;
153 	} else if (nr_copies == 0) {
154 		goto out;
155 	}
156 
157 	copy_idx = last_idx - nr_copies + 1;
158 	for (i = 0; i < nr_copies; i++) {
159 		bool *flag;
160 
161 		flag = dma_info->pkts_cmpl_flag_addr[copy_idx & ring_mask];
162 		if (flag) {
163 			/**
164 			 * Mark the packet flag as received. The flag
165 			 * could belong to another virtqueue but write
166 			 * is atomic.
167 			 */
168 			*flag = true;
169 			dma_info->pkts_cmpl_flag_addr[copy_idx & ring_mask] = NULL;
170 		}
171 		copy_idx++;
172 	}
173 
174 out:
175 	rte_spinlock_unlock(&dma_info->dma_lock);
176 	return nr_copies;
177 }
178 
179 static inline void
180 do_data_copy_enqueue(struct virtio_net *dev, struct vhost_virtqueue *vq)
181 {
182 	struct batch_copy_elem *elem = vq->batch_copy_elems;
183 	uint16_t count = vq->batch_copy_nb_elems;
184 	int i;
185 
186 	for (i = 0; i < count; i++) {
187 		rte_memcpy(elem[i].dst, elem[i].src, elem[i].len);
188 		vhost_log_cache_write_iova(dev, vq, elem[i].log_addr,
189 					   elem[i].len);
190 		PRINT_PACKET(dev, (uintptr_t)elem[i].dst, elem[i].len, 0);
191 	}
192 
193 	vq->batch_copy_nb_elems = 0;
194 }
195 
196 static inline void
197 do_data_copy_dequeue(struct vhost_virtqueue *vq)
198 {
199 	struct batch_copy_elem *elem = vq->batch_copy_elems;
200 	uint16_t count = vq->batch_copy_nb_elems;
201 	int i;
202 
203 	for (i = 0; i < count; i++)
204 		rte_memcpy(elem[i].dst, elem[i].src, elem[i].len);
205 
206 	vq->batch_copy_nb_elems = 0;
207 }
208 
209 static __rte_always_inline void
210 do_flush_shadow_used_ring_split(struct virtio_net *dev,
211 			struct vhost_virtqueue *vq,
212 			uint16_t to, uint16_t from, uint16_t size)
213 {
214 	rte_memcpy(&vq->used->ring[to],
215 			&vq->shadow_used_split[from],
216 			size * sizeof(struct vring_used_elem));
217 	vhost_log_cache_used_vring(dev, vq,
218 			offsetof(struct vring_used, ring[to]),
219 			size * sizeof(struct vring_used_elem));
220 }
221 
222 static __rte_always_inline void
223 flush_shadow_used_ring_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
224 {
225 	uint16_t used_idx = vq->last_used_idx & (vq->size - 1);
226 
227 	if (used_idx + vq->shadow_used_idx <= vq->size) {
228 		do_flush_shadow_used_ring_split(dev, vq, used_idx, 0,
229 					  vq->shadow_used_idx);
230 	} else {
231 		uint16_t size;
232 
233 		/* update used ring interval [used_idx, vq->size] */
234 		size = vq->size - used_idx;
235 		do_flush_shadow_used_ring_split(dev, vq, used_idx, 0, size);
236 
237 		/* update the left half used ring interval [0, left_size] */
238 		do_flush_shadow_used_ring_split(dev, vq, 0, size,
239 					  vq->shadow_used_idx - size);
240 	}
241 	vq->last_used_idx += vq->shadow_used_idx;
242 
243 	vhost_log_cache_sync(dev, vq);
244 
245 	__atomic_add_fetch(&vq->used->idx, vq->shadow_used_idx,
246 			   __ATOMIC_RELEASE);
247 	vq->shadow_used_idx = 0;
248 	vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
249 		sizeof(vq->used->idx));
250 }
251 
252 static __rte_always_inline void
253 update_shadow_used_ring_split(struct vhost_virtqueue *vq,
254 			 uint16_t desc_idx, uint32_t len)
255 {
256 	uint16_t i = vq->shadow_used_idx++;
257 
258 	vq->shadow_used_split[i].id  = desc_idx;
259 	vq->shadow_used_split[i].len = len;
260 }
261 
262 static __rte_always_inline void
263 vhost_flush_enqueue_shadow_packed(struct virtio_net *dev,
264 				  struct vhost_virtqueue *vq)
265 {
266 	int i;
267 	uint16_t used_idx = vq->last_used_idx;
268 	uint16_t head_idx = vq->last_used_idx;
269 	uint16_t head_flags = 0;
270 
271 	/* Split loop in two to save memory barriers */
272 	for (i = 0; i < vq->shadow_used_idx; i++) {
273 		vq->desc_packed[used_idx].id = vq->shadow_used_packed[i].id;
274 		vq->desc_packed[used_idx].len = vq->shadow_used_packed[i].len;
275 
276 		used_idx += vq->shadow_used_packed[i].count;
277 		if (used_idx >= vq->size)
278 			used_idx -= vq->size;
279 	}
280 
281 	/* The ordering for storing desc flags needs to be enforced. */
282 	rte_atomic_thread_fence(__ATOMIC_RELEASE);
283 
284 	for (i = 0; i < vq->shadow_used_idx; i++) {
285 		uint16_t flags;
286 
287 		if (vq->shadow_used_packed[i].len)
288 			flags = VRING_DESC_F_WRITE;
289 		else
290 			flags = 0;
291 
292 		if (vq->used_wrap_counter) {
293 			flags |= VRING_DESC_F_USED;
294 			flags |= VRING_DESC_F_AVAIL;
295 		} else {
296 			flags &= ~VRING_DESC_F_USED;
297 			flags &= ~VRING_DESC_F_AVAIL;
298 		}
299 
300 		if (i > 0) {
301 			vq->desc_packed[vq->last_used_idx].flags = flags;
302 
303 			vhost_log_cache_used_vring(dev, vq,
304 					vq->last_used_idx *
305 					sizeof(struct vring_packed_desc),
306 					sizeof(struct vring_packed_desc));
307 		} else {
308 			head_idx = vq->last_used_idx;
309 			head_flags = flags;
310 		}
311 
312 		vq_inc_last_used_packed(vq, vq->shadow_used_packed[i].count);
313 	}
314 
315 	vq->desc_packed[head_idx].flags = head_flags;
316 
317 	vhost_log_cache_used_vring(dev, vq,
318 				head_idx *
319 				sizeof(struct vring_packed_desc),
320 				sizeof(struct vring_packed_desc));
321 
322 	vq->shadow_used_idx = 0;
323 	vhost_log_cache_sync(dev, vq);
324 }
325 
326 static __rte_always_inline void
327 vhost_flush_dequeue_shadow_packed(struct virtio_net *dev,
328 				  struct vhost_virtqueue *vq)
329 {
330 	struct vring_used_elem_packed *used_elem = &vq->shadow_used_packed[0];
331 
332 	vq->desc_packed[vq->shadow_last_used_idx].id = used_elem->id;
333 	/* desc flags is the synchronization point for virtio packed vring */
334 	__atomic_store_n(&vq->desc_packed[vq->shadow_last_used_idx].flags,
335 			 used_elem->flags, __ATOMIC_RELEASE);
336 
337 	vhost_log_cache_used_vring(dev, vq, vq->shadow_last_used_idx *
338 				   sizeof(struct vring_packed_desc),
339 				   sizeof(struct vring_packed_desc));
340 	vq->shadow_used_idx = 0;
341 	vhost_log_cache_sync(dev, vq);
342 }
343 
344 static __rte_always_inline void
345 vhost_flush_enqueue_batch_packed(struct virtio_net *dev,
346 				 struct vhost_virtqueue *vq,
347 				 uint64_t *lens,
348 				 uint16_t *ids)
349 {
350 	uint16_t i;
351 	uint16_t flags;
352 	uint16_t last_used_idx;
353 	struct vring_packed_desc *desc_base;
354 
355 	last_used_idx = vq->last_used_idx;
356 	desc_base = &vq->desc_packed[last_used_idx];
357 
358 	flags = PACKED_DESC_ENQUEUE_USED_FLAG(vq->used_wrap_counter);
359 
360 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
361 		desc_base[i].id = ids[i];
362 		desc_base[i].len = lens[i];
363 	}
364 
365 	rte_atomic_thread_fence(__ATOMIC_RELEASE);
366 
367 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
368 		desc_base[i].flags = flags;
369 	}
370 
371 	vhost_log_cache_used_vring(dev, vq, last_used_idx *
372 				   sizeof(struct vring_packed_desc),
373 				   sizeof(struct vring_packed_desc) *
374 				   PACKED_BATCH_SIZE);
375 	vhost_log_cache_sync(dev, vq);
376 
377 	vq_inc_last_used_packed(vq, PACKED_BATCH_SIZE);
378 }
379 
380 static __rte_always_inline void
381 vhost_shadow_dequeue_batch_packed_inorder(struct vhost_virtqueue *vq,
382 					  uint16_t id)
383 {
384 	vq->shadow_used_packed[0].id = id;
385 
386 	if (!vq->shadow_used_idx) {
387 		vq->shadow_last_used_idx = vq->last_used_idx;
388 		vq->shadow_used_packed[0].flags =
389 			PACKED_DESC_DEQUEUE_USED_FLAG(vq->used_wrap_counter);
390 		vq->shadow_used_packed[0].len = 0;
391 		vq->shadow_used_packed[0].count = 1;
392 		vq->shadow_used_idx++;
393 	}
394 
395 	vq_inc_last_used_packed(vq, PACKED_BATCH_SIZE);
396 }
397 
398 static __rte_always_inline void
399 vhost_shadow_dequeue_batch_packed(struct virtio_net *dev,
400 				  struct vhost_virtqueue *vq,
401 				  uint16_t *ids)
402 {
403 	uint16_t flags;
404 	uint16_t i;
405 	uint16_t begin;
406 
407 	flags = PACKED_DESC_DEQUEUE_USED_FLAG(vq->used_wrap_counter);
408 
409 	if (!vq->shadow_used_idx) {
410 		vq->shadow_last_used_idx = vq->last_used_idx;
411 		vq->shadow_used_packed[0].id  = ids[0];
412 		vq->shadow_used_packed[0].len = 0;
413 		vq->shadow_used_packed[0].count = 1;
414 		vq->shadow_used_packed[0].flags = flags;
415 		vq->shadow_used_idx++;
416 		begin = 1;
417 	} else
418 		begin = 0;
419 
420 	vhost_for_each_try_unroll(i, begin, PACKED_BATCH_SIZE) {
421 		vq->desc_packed[vq->last_used_idx + i].id = ids[i];
422 		vq->desc_packed[vq->last_used_idx + i].len = 0;
423 	}
424 
425 	rte_atomic_thread_fence(__ATOMIC_RELEASE);
426 	vhost_for_each_try_unroll(i, begin, PACKED_BATCH_SIZE)
427 		vq->desc_packed[vq->last_used_idx + i].flags = flags;
428 
429 	vhost_log_cache_used_vring(dev, vq, vq->last_used_idx *
430 				   sizeof(struct vring_packed_desc),
431 				   sizeof(struct vring_packed_desc) *
432 				   PACKED_BATCH_SIZE);
433 	vhost_log_cache_sync(dev, vq);
434 
435 	vq_inc_last_used_packed(vq, PACKED_BATCH_SIZE);
436 }
437 
438 static __rte_always_inline void
439 vhost_shadow_dequeue_single_packed(struct vhost_virtqueue *vq,
440 				   uint16_t buf_id,
441 				   uint16_t count)
442 {
443 	uint16_t flags;
444 
445 	flags = vq->desc_packed[vq->last_used_idx].flags;
446 	if (vq->used_wrap_counter) {
447 		flags |= VRING_DESC_F_USED;
448 		flags |= VRING_DESC_F_AVAIL;
449 	} else {
450 		flags &= ~VRING_DESC_F_USED;
451 		flags &= ~VRING_DESC_F_AVAIL;
452 	}
453 
454 	if (!vq->shadow_used_idx) {
455 		vq->shadow_last_used_idx = vq->last_used_idx;
456 
457 		vq->shadow_used_packed[0].id  = buf_id;
458 		vq->shadow_used_packed[0].len = 0;
459 		vq->shadow_used_packed[0].flags = flags;
460 		vq->shadow_used_idx++;
461 	} else {
462 		vq->desc_packed[vq->last_used_idx].id = buf_id;
463 		vq->desc_packed[vq->last_used_idx].len = 0;
464 		vq->desc_packed[vq->last_used_idx].flags = flags;
465 	}
466 
467 	vq_inc_last_used_packed(vq, count);
468 }
469 
470 static __rte_always_inline void
471 vhost_shadow_dequeue_single_packed_inorder(struct vhost_virtqueue *vq,
472 					   uint16_t buf_id,
473 					   uint16_t count)
474 {
475 	uint16_t flags;
476 
477 	vq->shadow_used_packed[0].id = buf_id;
478 
479 	flags = vq->desc_packed[vq->last_used_idx].flags;
480 	if (vq->used_wrap_counter) {
481 		flags |= VRING_DESC_F_USED;
482 		flags |= VRING_DESC_F_AVAIL;
483 	} else {
484 		flags &= ~VRING_DESC_F_USED;
485 		flags &= ~VRING_DESC_F_AVAIL;
486 	}
487 
488 	if (!vq->shadow_used_idx) {
489 		vq->shadow_last_used_idx = vq->last_used_idx;
490 		vq->shadow_used_packed[0].len = 0;
491 		vq->shadow_used_packed[0].flags = flags;
492 		vq->shadow_used_idx++;
493 	}
494 
495 	vq_inc_last_used_packed(vq, count);
496 }
497 
498 static __rte_always_inline void
499 vhost_shadow_enqueue_packed(struct vhost_virtqueue *vq,
500 				   uint32_t *len,
501 				   uint16_t *id,
502 				   uint16_t *count,
503 				   uint16_t num_buffers)
504 {
505 	uint16_t i;
506 
507 	for (i = 0; i < num_buffers; i++) {
508 		/* enqueue shadow flush action aligned with batch num */
509 		if (!vq->shadow_used_idx)
510 			vq->shadow_aligned_idx = vq->last_used_idx &
511 				PACKED_BATCH_MASK;
512 		vq->shadow_used_packed[vq->shadow_used_idx].id  = id[i];
513 		vq->shadow_used_packed[vq->shadow_used_idx].len = len[i];
514 		vq->shadow_used_packed[vq->shadow_used_idx].count = count[i];
515 		vq->shadow_aligned_idx += count[i];
516 		vq->shadow_used_idx++;
517 	}
518 }
519 
520 static __rte_always_inline void
521 vhost_shadow_enqueue_single_packed(struct virtio_net *dev,
522 				   struct vhost_virtqueue *vq,
523 				   uint32_t *len,
524 				   uint16_t *id,
525 				   uint16_t *count,
526 				   uint16_t num_buffers)
527 {
528 	vhost_shadow_enqueue_packed(vq, len, id, count, num_buffers);
529 
530 	if (vq->shadow_aligned_idx >= PACKED_BATCH_SIZE) {
531 		do_data_copy_enqueue(dev, vq);
532 		vhost_flush_enqueue_shadow_packed(dev, vq);
533 	}
534 }
535 
536 /* avoid write operation when necessary, to lessen cache issues */
537 #define ASSIGN_UNLESS_EQUAL(var, val) do {	\
538 	if ((var) != (val))			\
539 		(var) = (val);			\
540 } while (0)
541 
542 static __rte_always_inline void
543 virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
544 {
545 	uint64_t csum_l4 = m_buf->ol_flags & RTE_MBUF_F_TX_L4_MASK;
546 
547 	if (m_buf->ol_flags & RTE_MBUF_F_TX_TCP_SEG)
548 		csum_l4 |= RTE_MBUF_F_TX_TCP_CKSUM;
549 
550 	if (csum_l4) {
551 		net_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
552 		net_hdr->csum_start = m_buf->l2_len + m_buf->l3_len;
553 
554 		switch (csum_l4) {
555 		case RTE_MBUF_F_TX_TCP_CKSUM:
556 			net_hdr->csum_offset = (offsetof(struct rte_tcp_hdr,
557 						cksum));
558 			break;
559 		case RTE_MBUF_F_TX_UDP_CKSUM:
560 			net_hdr->csum_offset = (offsetof(struct rte_udp_hdr,
561 						dgram_cksum));
562 			break;
563 		case RTE_MBUF_F_TX_SCTP_CKSUM:
564 			net_hdr->csum_offset = (offsetof(struct rte_sctp_hdr,
565 						cksum));
566 			break;
567 		}
568 	} else {
569 		ASSIGN_UNLESS_EQUAL(net_hdr->csum_start, 0);
570 		ASSIGN_UNLESS_EQUAL(net_hdr->csum_offset, 0);
571 		ASSIGN_UNLESS_EQUAL(net_hdr->flags, 0);
572 	}
573 
574 	/* IP cksum verification cannot be bypassed, then calculate here */
575 	if (m_buf->ol_flags & RTE_MBUF_F_TX_IP_CKSUM) {
576 		struct rte_ipv4_hdr *ipv4_hdr;
577 
578 		ipv4_hdr = rte_pktmbuf_mtod_offset(m_buf, struct rte_ipv4_hdr *,
579 						   m_buf->l2_len);
580 		ipv4_hdr->hdr_checksum = 0;
581 		ipv4_hdr->hdr_checksum = rte_ipv4_cksum(ipv4_hdr);
582 	}
583 
584 	if (m_buf->ol_flags & RTE_MBUF_F_TX_TCP_SEG) {
585 		if (m_buf->ol_flags & RTE_MBUF_F_TX_IPV4)
586 			net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
587 		else
588 			net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
589 		net_hdr->gso_size = m_buf->tso_segsz;
590 		net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len
591 					+ m_buf->l4_len;
592 	} else if (m_buf->ol_flags & RTE_MBUF_F_TX_UDP_SEG) {
593 		net_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
594 		net_hdr->gso_size = m_buf->tso_segsz;
595 		net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len +
596 			m_buf->l4_len;
597 	} else {
598 		ASSIGN_UNLESS_EQUAL(net_hdr->gso_type, 0);
599 		ASSIGN_UNLESS_EQUAL(net_hdr->gso_size, 0);
600 		ASSIGN_UNLESS_EQUAL(net_hdr->hdr_len, 0);
601 	}
602 }
603 
604 static __rte_always_inline int
605 map_one_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
606 		struct buf_vector *buf_vec, uint16_t *vec_idx,
607 		uint64_t desc_iova, uint64_t desc_len, uint8_t perm)
608 {
609 	uint16_t vec_id = *vec_idx;
610 
611 	while (desc_len) {
612 		uint64_t desc_addr;
613 		uint64_t desc_chunck_len = desc_len;
614 
615 		if (unlikely(vec_id >= BUF_VECTOR_MAX))
616 			return -1;
617 
618 		desc_addr = vhost_iova_to_vva(dev, vq,
619 				desc_iova,
620 				&desc_chunck_len,
621 				perm);
622 		if (unlikely(!desc_addr))
623 			return -1;
624 
625 		rte_prefetch0((void *)(uintptr_t)desc_addr);
626 
627 		buf_vec[vec_id].buf_iova = desc_iova;
628 		buf_vec[vec_id].buf_addr = desc_addr;
629 		buf_vec[vec_id].buf_len  = desc_chunck_len;
630 
631 		desc_len -= desc_chunck_len;
632 		desc_iova += desc_chunck_len;
633 		vec_id++;
634 	}
635 	*vec_idx = vec_id;
636 
637 	return 0;
638 }
639 
640 static __rte_always_inline int
641 fill_vec_buf_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
642 			 uint32_t avail_idx, uint16_t *vec_idx,
643 			 struct buf_vector *buf_vec, uint16_t *desc_chain_head,
644 			 uint32_t *desc_chain_len, uint8_t perm)
645 {
646 	uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)];
647 	uint16_t vec_id = *vec_idx;
648 	uint32_t len    = 0;
649 	uint64_t dlen;
650 	uint32_t nr_descs = vq->size;
651 	uint32_t cnt    = 0;
652 	struct vring_desc *descs = vq->desc;
653 	struct vring_desc *idesc = NULL;
654 
655 	if (unlikely(idx >= vq->size))
656 		return -1;
657 
658 	*desc_chain_head = idx;
659 
660 	if (vq->desc[idx].flags & VRING_DESC_F_INDIRECT) {
661 		dlen = vq->desc[idx].len;
662 		nr_descs = dlen / sizeof(struct vring_desc);
663 		if (unlikely(nr_descs > vq->size))
664 			return -1;
665 
666 		descs = (struct vring_desc *)(uintptr_t)
667 			vhost_iova_to_vva(dev, vq, vq->desc[idx].addr,
668 						&dlen,
669 						VHOST_ACCESS_RO);
670 		if (unlikely(!descs))
671 			return -1;
672 
673 		if (unlikely(dlen < vq->desc[idx].len)) {
674 			/*
675 			 * The indirect desc table is not contiguous
676 			 * in process VA space, we have to copy it.
677 			 */
678 			idesc = vhost_alloc_copy_ind_table(dev, vq,
679 					vq->desc[idx].addr, vq->desc[idx].len);
680 			if (unlikely(!idesc))
681 				return -1;
682 
683 			descs = idesc;
684 		}
685 
686 		idx = 0;
687 	}
688 
689 	while (1) {
690 		if (unlikely(idx >= nr_descs || cnt++ >= nr_descs)) {
691 			free_ind_table(idesc);
692 			return -1;
693 		}
694 
695 		dlen = descs[idx].len;
696 		len += dlen;
697 
698 		if (unlikely(map_one_desc(dev, vq, buf_vec, &vec_id,
699 						descs[idx].addr, dlen,
700 						perm))) {
701 			free_ind_table(idesc);
702 			return -1;
703 		}
704 
705 		if ((descs[idx].flags & VRING_DESC_F_NEXT) == 0)
706 			break;
707 
708 		idx = descs[idx].next;
709 	}
710 
711 	*desc_chain_len = len;
712 	*vec_idx = vec_id;
713 
714 	if (unlikely(!!idesc))
715 		free_ind_table(idesc);
716 
717 	return 0;
718 }
719 
720 /*
721  * Returns -1 on fail, 0 on success
722  */
723 static inline int
724 reserve_avail_buf_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
725 				uint32_t size, struct buf_vector *buf_vec,
726 				uint16_t *num_buffers, uint16_t avail_head,
727 				uint16_t *nr_vec)
728 {
729 	uint16_t cur_idx;
730 	uint16_t vec_idx = 0;
731 	uint16_t max_tries, tries = 0;
732 
733 	uint16_t head_idx = 0;
734 	uint32_t len = 0;
735 
736 	*num_buffers = 0;
737 	cur_idx  = vq->last_avail_idx;
738 
739 	if (rxvq_is_mergeable(dev))
740 		max_tries = vq->size - 1;
741 	else
742 		max_tries = 1;
743 
744 	while (size > 0) {
745 		if (unlikely(cur_idx == avail_head))
746 			return -1;
747 		/*
748 		 * if we tried all available ring items, and still
749 		 * can't get enough buf, it means something abnormal
750 		 * happened.
751 		 */
752 		if (unlikely(++tries > max_tries))
753 			return -1;
754 
755 		if (unlikely(fill_vec_buf_split(dev, vq, cur_idx,
756 						&vec_idx, buf_vec,
757 						&head_idx, &len,
758 						VHOST_ACCESS_RW) < 0))
759 			return -1;
760 		len = RTE_MIN(len, size);
761 		update_shadow_used_ring_split(vq, head_idx, len);
762 		size -= len;
763 
764 		cur_idx++;
765 		*num_buffers += 1;
766 	}
767 
768 	*nr_vec = vec_idx;
769 
770 	return 0;
771 }
772 
773 static __rte_always_inline int
774 fill_vec_buf_packed_indirect(struct virtio_net *dev,
775 			struct vhost_virtqueue *vq,
776 			struct vring_packed_desc *desc, uint16_t *vec_idx,
777 			struct buf_vector *buf_vec, uint32_t *len, uint8_t perm)
778 {
779 	uint16_t i;
780 	uint32_t nr_descs;
781 	uint16_t vec_id = *vec_idx;
782 	uint64_t dlen;
783 	struct vring_packed_desc *descs, *idescs = NULL;
784 
785 	dlen = desc->len;
786 	descs = (struct vring_packed_desc *)(uintptr_t)
787 		vhost_iova_to_vva(dev, vq, desc->addr, &dlen, VHOST_ACCESS_RO);
788 	if (unlikely(!descs))
789 		return -1;
790 
791 	if (unlikely(dlen < desc->len)) {
792 		/*
793 		 * The indirect desc table is not contiguous
794 		 * in process VA space, we have to copy it.
795 		 */
796 		idescs = vhost_alloc_copy_ind_table(dev,
797 				vq, desc->addr, desc->len);
798 		if (unlikely(!idescs))
799 			return -1;
800 
801 		descs = idescs;
802 	}
803 
804 	nr_descs =  desc->len / sizeof(struct vring_packed_desc);
805 	if (unlikely(nr_descs >= vq->size)) {
806 		free_ind_table(idescs);
807 		return -1;
808 	}
809 
810 	for (i = 0; i < nr_descs; i++) {
811 		if (unlikely(vec_id >= BUF_VECTOR_MAX)) {
812 			free_ind_table(idescs);
813 			return -1;
814 		}
815 
816 		dlen = descs[i].len;
817 		*len += dlen;
818 		if (unlikely(map_one_desc(dev, vq, buf_vec, &vec_id,
819 						descs[i].addr, dlen,
820 						perm)))
821 			return -1;
822 	}
823 	*vec_idx = vec_id;
824 
825 	if (unlikely(!!idescs))
826 		free_ind_table(idescs);
827 
828 	return 0;
829 }
830 
831 static __rte_always_inline int
832 fill_vec_buf_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
833 				uint16_t avail_idx, uint16_t *desc_count,
834 				struct buf_vector *buf_vec, uint16_t *vec_idx,
835 				uint16_t *buf_id, uint32_t *len, uint8_t perm)
836 {
837 	bool wrap_counter = vq->avail_wrap_counter;
838 	struct vring_packed_desc *descs = vq->desc_packed;
839 	uint16_t vec_id = *vec_idx;
840 	uint64_t dlen;
841 
842 	if (avail_idx < vq->last_avail_idx)
843 		wrap_counter ^= 1;
844 
845 	/*
846 	 * Perform a load-acquire barrier in desc_is_avail to
847 	 * enforce the ordering between desc flags and desc
848 	 * content.
849 	 */
850 	if (unlikely(!desc_is_avail(&descs[avail_idx], wrap_counter)))
851 		return -1;
852 
853 	*desc_count = 0;
854 	*len = 0;
855 
856 	while (1) {
857 		if (unlikely(vec_id >= BUF_VECTOR_MAX))
858 			return -1;
859 
860 		if (unlikely(*desc_count >= vq->size))
861 			return -1;
862 
863 		*desc_count += 1;
864 		*buf_id = descs[avail_idx].id;
865 
866 		if (descs[avail_idx].flags & VRING_DESC_F_INDIRECT) {
867 			if (unlikely(fill_vec_buf_packed_indirect(dev, vq,
868 							&descs[avail_idx],
869 							&vec_id, buf_vec,
870 							len, perm) < 0))
871 				return -1;
872 		} else {
873 			dlen = descs[avail_idx].len;
874 			*len += dlen;
875 
876 			if (unlikely(map_one_desc(dev, vq, buf_vec, &vec_id,
877 							descs[avail_idx].addr,
878 							dlen,
879 							perm)))
880 				return -1;
881 		}
882 
883 		if ((descs[avail_idx].flags & VRING_DESC_F_NEXT) == 0)
884 			break;
885 
886 		if (++avail_idx >= vq->size) {
887 			avail_idx -= vq->size;
888 			wrap_counter ^= 1;
889 		}
890 	}
891 
892 	*vec_idx = vec_id;
893 
894 	return 0;
895 }
896 
897 static __rte_noinline void
898 copy_vnet_hdr_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
899 		struct buf_vector *buf_vec,
900 		struct virtio_net_hdr_mrg_rxbuf *hdr)
901 {
902 	uint64_t len;
903 	uint64_t remain = dev->vhost_hlen;
904 	uint64_t src = (uint64_t)(uintptr_t)hdr, dst;
905 	uint64_t iova = buf_vec->buf_iova;
906 
907 	while (remain) {
908 		len = RTE_MIN(remain,
909 				buf_vec->buf_len);
910 		dst = buf_vec->buf_addr;
911 		rte_memcpy((void *)(uintptr_t)dst,
912 				(void *)(uintptr_t)src,
913 				len);
914 
915 		PRINT_PACKET(dev, (uintptr_t)dst,
916 				(uint32_t)len, 0);
917 		vhost_log_cache_write_iova(dev, vq,
918 				iova, len);
919 
920 		remain -= len;
921 		iova += len;
922 		src += len;
923 		buf_vec++;
924 	}
925 }
926 
927 static __rte_always_inline int
928 async_iter_initialize(struct virtio_net *dev, struct vhost_async *async)
929 {
930 	struct vhost_iov_iter *iter;
931 
932 	if (unlikely(async->iovec_idx >= VHOST_MAX_ASYNC_VEC)) {
933 		VHOST_LOG_DATA(ERR, "(%s) no more async iovec available\n", dev->ifname);
934 		return -1;
935 	}
936 
937 	iter = async->iov_iter + async->iter_idx;
938 	iter->iov = async->iovec + async->iovec_idx;
939 	iter->nr_segs = 0;
940 
941 	return 0;
942 }
943 
944 static __rte_always_inline int
945 async_iter_add_iovec(struct virtio_net *dev, struct vhost_async *async,
946 		void *src, void *dst, size_t len)
947 {
948 	struct vhost_iov_iter *iter;
949 	struct vhost_iovec *iovec;
950 
951 	if (unlikely(async->iovec_idx >= VHOST_MAX_ASYNC_VEC)) {
952 		static bool vhost_max_async_vec_log;
953 
954 		if (!vhost_max_async_vec_log) {
955 			VHOST_LOG_DATA(ERR, "(%s) no more async iovec available\n", dev->ifname);
956 			vhost_max_async_vec_log = true;
957 		}
958 
959 		return -1;
960 	}
961 
962 	iter = async->iov_iter + async->iter_idx;
963 	iovec = async->iovec + async->iovec_idx;
964 
965 	iovec->src_addr = src;
966 	iovec->dst_addr = dst;
967 	iovec->len = len;
968 
969 	iter->nr_segs++;
970 	async->iovec_idx++;
971 
972 	return 0;
973 }
974 
975 static __rte_always_inline void
976 async_iter_finalize(struct vhost_async *async)
977 {
978 	async->iter_idx++;
979 }
980 
981 static __rte_always_inline void
982 async_iter_cancel(struct vhost_async *async)
983 {
984 	struct vhost_iov_iter *iter;
985 
986 	iter = async->iov_iter + async->iter_idx;
987 	async->iovec_idx -= iter->nr_segs;
988 	iter->nr_segs = 0;
989 	iter->iov = NULL;
990 }
991 
992 static __rte_always_inline void
993 async_iter_reset(struct vhost_async *async)
994 {
995 	async->iter_idx = 0;
996 	async->iovec_idx = 0;
997 }
998 
999 static __rte_always_inline int
1000 async_mbuf_to_desc_seg(struct virtio_net *dev, struct vhost_virtqueue *vq,
1001 		struct rte_mbuf *m, uint32_t mbuf_offset,
1002 		uint64_t buf_iova, uint32_t cpy_len)
1003 {
1004 	struct vhost_async *async = vq->async;
1005 	uint64_t mapped_len;
1006 	uint32_t buf_offset = 0;
1007 	void *host_iova;
1008 
1009 	while (cpy_len) {
1010 		host_iova = (void *)(uintptr_t)gpa_to_first_hpa(dev,
1011 				buf_iova + buf_offset, cpy_len, &mapped_len);
1012 		if (unlikely(!host_iova)) {
1013 			VHOST_LOG_DATA(ERR, "(%s) %s: failed to get host iova.\n",
1014 				       dev->ifname, __func__);
1015 			return -1;
1016 		}
1017 
1018 		if (unlikely(async_iter_add_iovec(dev, async,
1019 						(void *)(uintptr_t)rte_pktmbuf_iova_offset(m,
1020 							mbuf_offset),
1021 						host_iova, (size_t)mapped_len)))
1022 			return -1;
1023 
1024 		cpy_len -= (uint32_t)mapped_len;
1025 		mbuf_offset += (uint32_t)mapped_len;
1026 		buf_offset += (uint32_t)mapped_len;
1027 	}
1028 
1029 	return 0;
1030 }
1031 
1032 static __rte_always_inline void
1033 sync_mbuf_to_desc_seg(struct virtio_net *dev, struct vhost_virtqueue *vq,
1034 		struct rte_mbuf *m, uint32_t mbuf_offset,
1035 		uint64_t buf_addr, uint64_t buf_iova, uint32_t cpy_len)
1036 {
1037 	struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
1038 
1039 	if (likely(cpy_len > MAX_BATCH_LEN || vq->batch_copy_nb_elems >= vq->size)) {
1040 		rte_memcpy((void *)((uintptr_t)(buf_addr)),
1041 				rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
1042 				cpy_len);
1043 		vhost_log_cache_write_iova(dev, vq, buf_iova, cpy_len);
1044 		PRINT_PACKET(dev, (uintptr_t)(buf_addr), cpy_len, 0);
1045 	} else {
1046 		batch_copy[vq->batch_copy_nb_elems].dst =
1047 			(void *)((uintptr_t)(buf_addr));
1048 		batch_copy[vq->batch_copy_nb_elems].src =
1049 			rte_pktmbuf_mtod_offset(m, void *, mbuf_offset);
1050 		batch_copy[vq->batch_copy_nb_elems].log_addr = buf_iova;
1051 		batch_copy[vq->batch_copy_nb_elems].len = cpy_len;
1052 		vq->batch_copy_nb_elems++;
1053 	}
1054 }
1055 
1056 static __rte_always_inline int
1057 mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
1058 		struct rte_mbuf *m, struct buf_vector *buf_vec,
1059 		uint16_t nr_vec, uint16_t num_buffers, bool is_async)
1060 {
1061 	uint32_t vec_idx = 0;
1062 	uint32_t mbuf_offset, mbuf_avail;
1063 	uint32_t buf_offset, buf_avail;
1064 	uint64_t buf_addr, buf_iova, buf_len;
1065 	uint32_t cpy_len;
1066 	uint64_t hdr_addr;
1067 	struct rte_mbuf *hdr_mbuf;
1068 	struct virtio_net_hdr_mrg_rxbuf tmp_hdr, *hdr = NULL;
1069 	struct vhost_async *async = vq->async;
1070 
1071 	if (unlikely(m == NULL))
1072 		return -1;
1073 
1074 	buf_addr = buf_vec[vec_idx].buf_addr;
1075 	buf_iova = buf_vec[vec_idx].buf_iova;
1076 	buf_len = buf_vec[vec_idx].buf_len;
1077 
1078 	if (unlikely(buf_len < dev->vhost_hlen && nr_vec <= 1))
1079 		return -1;
1080 
1081 	hdr_mbuf = m;
1082 	hdr_addr = buf_addr;
1083 	if (unlikely(buf_len < dev->vhost_hlen)) {
1084 		memset(&tmp_hdr, 0, sizeof(struct virtio_net_hdr_mrg_rxbuf));
1085 		hdr = &tmp_hdr;
1086 	} else
1087 		hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)hdr_addr;
1088 
1089 	VHOST_LOG_DATA(DEBUG, "(%s) RX: num merge buffers %d\n",
1090 		dev->ifname, num_buffers);
1091 
1092 	if (unlikely(buf_len < dev->vhost_hlen)) {
1093 		buf_offset = dev->vhost_hlen - buf_len;
1094 		vec_idx++;
1095 		buf_addr = buf_vec[vec_idx].buf_addr;
1096 		buf_iova = buf_vec[vec_idx].buf_iova;
1097 		buf_len = buf_vec[vec_idx].buf_len;
1098 		buf_avail = buf_len - buf_offset;
1099 	} else {
1100 		buf_offset = dev->vhost_hlen;
1101 		buf_avail = buf_len - dev->vhost_hlen;
1102 	}
1103 
1104 	mbuf_avail  = rte_pktmbuf_data_len(m);
1105 	mbuf_offset = 0;
1106 
1107 	if (is_async) {
1108 		if (async_iter_initialize(dev, async))
1109 			return -1;
1110 	}
1111 
1112 	while (mbuf_avail != 0 || m->next != NULL) {
1113 		/* done with current buf, get the next one */
1114 		if (buf_avail == 0) {
1115 			vec_idx++;
1116 			if (unlikely(vec_idx >= nr_vec))
1117 				goto error;
1118 
1119 			buf_addr = buf_vec[vec_idx].buf_addr;
1120 			buf_iova = buf_vec[vec_idx].buf_iova;
1121 			buf_len = buf_vec[vec_idx].buf_len;
1122 
1123 			buf_offset = 0;
1124 			buf_avail  = buf_len;
1125 		}
1126 
1127 		/* done with current mbuf, get the next one */
1128 		if (mbuf_avail == 0) {
1129 			m = m->next;
1130 
1131 			mbuf_offset = 0;
1132 			mbuf_avail  = rte_pktmbuf_data_len(m);
1133 		}
1134 
1135 		if (hdr_addr) {
1136 			virtio_enqueue_offload(hdr_mbuf, &hdr->hdr);
1137 			if (rxvq_is_mergeable(dev))
1138 				ASSIGN_UNLESS_EQUAL(hdr->num_buffers,
1139 						num_buffers);
1140 
1141 			if (unlikely(hdr == &tmp_hdr)) {
1142 				copy_vnet_hdr_to_desc(dev, vq, buf_vec, hdr);
1143 			} else {
1144 				PRINT_PACKET(dev, (uintptr_t)hdr_addr,
1145 						dev->vhost_hlen, 0);
1146 				vhost_log_cache_write_iova(dev, vq,
1147 						buf_vec[0].buf_iova,
1148 						dev->vhost_hlen);
1149 			}
1150 
1151 			hdr_addr = 0;
1152 		}
1153 
1154 		cpy_len = RTE_MIN(buf_avail, mbuf_avail);
1155 
1156 		if (is_async) {
1157 			if (async_mbuf_to_desc_seg(dev, vq, m, mbuf_offset,
1158 						buf_iova + buf_offset, cpy_len) < 0)
1159 				goto error;
1160 		} else {
1161 			sync_mbuf_to_desc_seg(dev, vq, m, mbuf_offset,
1162 					buf_addr + buf_offset,
1163 					buf_iova + buf_offset, cpy_len);
1164 		}
1165 
1166 		mbuf_avail  -= cpy_len;
1167 		mbuf_offset += cpy_len;
1168 		buf_avail  -= cpy_len;
1169 		buf_offset += cpy_len;
1170 	}
1171 
1172 	if (is_async)
1173 		async_iter_finalize(async);
1174 
1175 	return 0;
1176 error:
1177 	if (is_async)
1178 		async_iter_cancel(async);
1179 
1180 	return -1;
1181 }
1182 
1183 static __rte_always_inline int
1184 vhost_enqueue_single_packed(struct virtio_net *dev,
1185 			    struct vhost_virtqueue *vq,
1186 			    struct rte_mbuf *pkt,
1187 			    struct buf_vector *buf_vec,
1188 			    uint16_t *nr_descs)
1189 {
1190 	uint16_t nr_vec = 0;
1191 	uint16_t avail_idx = vq->last_avail_idx;
1192 	uint16_t max_tries, tries = 0;
1193 	uint16_t buf_id = 0;
1194 	uint32_t len = 0;
1195 	uint16_t desc_count;
1196 	uint32_t size = pkt->pkt_len + sizeof(struct virtio_net_hdr_mrg_rxbuf);
1197 	uint16_t num_buffers = 0;
1198 	uint32_t buffer_len[vq->size];
1199 	uint16_t buffer_buf_id[vq->size];
1200 	uint16_t buffer_desc_count[vq->size];
1201 
1202 	if (rxvq_is_mergeable(dev))
1203 		max_tries = vq->size - 1;
1204 	else
1205 		max_tries = 1;
1206 
1207 	while (size > 0) {
1208 		/*
1209 		 * if we tried all available ring items, and still
1210 		 * can't get enough buf, it means something abnormal
1211 		 * happened.
1212 		 */
1213 		if (unlikely(++tries > max_tries))
1214 			return -1;
1215 
1216 		if (unlikely(fill_vec_buf_packed(dev, vq,
1217 						avail_idx, &desc_count,
1218 						buf_vec, &nr_vec,
1219 						&buf_id, &len,
1220 						VHOST_ACCESS_RW) < 0))
1221 			return -1;
1222 
1223 		len = RTE_MIN(len, size);
1224 		size -= len;
1225 
1226 		buffer_len[num_buffers] = len;
1227 		buffer_buf_id[num_buffers] = buf_id;
1228 		buffer_desc_count[num_buffers] = desc_count;
1229 		num_buffers += 1;
1230 
1231 		*nr_descs += desc_count;
1232 		avail_idx += desc_count;
1233 		if (avail_idx >= vq->size)
1234 			avail_idx -= vq->size;
1235 	}
1236 
1237 	if (mbuf_to_desc(dev, vq, pkt, buf_vec, nr_vec, num_buffers, false) < 0)
1238 		return -1;
1239 
1240 	vhost_shadow_enqueue_single_packed(dev, vq, buffer_len, buffer_buf_id,
1241 					   buffer_desc_count, num_buffers);
1242 
1243 	return 0;
1244 }
1245 
1246 static __rte_noinline uint32_t
1247 virtio_dev_rx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
1248 	struct rte_mbuf **pkts, uint32_t count)
1249 {
1250 	uint32_t pkt_idx = 0;
1251 	uint16_t num_buffers;
1252 	struct buf_vector buf_vec[BUF_VECTOR_MAX];
1253 	uint16_t avail_head;
1254 
1255 	/*
1256 	 * The ordering between avail index and
1257 	 * desc reads needs to be enforced.
1258 	 */
1259 	avail_head = __atomic_load_n(&vq->avail->idx, __ATOMIC_ACQUIRE);
1260 
1261 	rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
1262 
1263 	for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
1264 		uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
1265 		uint16_t nr_vec = 0;
1266 
1267 		if (unlikely(reserve_avail_buf_split(dev, vq,
1268 						pkt_len, buf_vec, &num_buffers,
1269 						avail_head, &nr_vec) < 0)) {
1270 			VHOST_LOG_DATA(DEBUG,
1271 				"(%s) failed to get enough desc from vring\n",
1272 				dev->ifname);
1273 			vq->shadow_used_idx -= num_buffers;
1274 			break;
1275 		}
1276 
1277 		VHOST_LOG_DATA(DEBUG, "(%s) current index %d | end index %d\n",
1278 			dev->ifname, vq->last_avail_idx,
1279 			vq->last_avail_idx + num_buffers);
1280 
1281 		if (mbuf_to_desc(dev, vq, pkts[pkt_idx], buf_vec, nr_vec,
1282 					num_buffers, false) < 0) {
1283 			vq->shadow_used_idx -= num_buffers;
1284 			break;
1285 		}
1286 
1287 		vq->last_avail_idx += num_buffers;
1288 	}
1289 
1290 	do_data_copy_enqueue(dev, vq);
1291 
1292 	if (likely(vq->shadow_used_idx)) {
1293 		flush_shadow_used_ring_split(dev, vq);
1294 		vhost_vring_call_split(dev, vq);
1295 	}
1296 
1297 	return pkt_idx;
1298 }
1299 
1300 static __rte_always_inline int
1301 virtio_dev_rx_sync_batch_check(struct virtio_net *dev,
1302 			   struct vhost_virtqueue *vq,
1303 			   struct rte_mbuf **pkts,
1304 			   uint64_t *desc_addrs,
1305 			   uint64_t *lens)
1306 {
1307 	bool wrap_counter = vq->avail_wrap_counter;
1308 	struct vring_packed_desc *descs = vq->desc_packed;
1309 	uint16_t avail_idx = vq->last_avail_idx;
1310 	uint32_t buf_offset = sizeof(struct virtio_net_hdr_mrg_rxbuf);
1311 	uint16_t i;
1312 
1313 	if (unlikely(avail_idx & PACKED_BATCH_MASK))
1314 		return -1;
1315 
1316 	if (unlikely((avail_idx + PACKED_BATCH_SIZE) > vq->size))
1317 		return -1;
1318 
1319 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
1320 		if (unlikely(pkts[i]->next != NULL))
1321 			return -1;
1322 		if (unlikely(!desc_is_avail(&descs[avail_idx + i],
1323 					    wrap_counter)))
1324 			return -1;
1325 	}
1326 
1327 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
1328 		lens[i] = descs[avail_idx + i].len;
1329 
1330 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
1331 		if (unlikely(pkts[i]->pkt_len > (lens[i] - buf_offset)))
1332 			return -1;
1333 	}
1334 
1335 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
1336 		desc_addrs[i] = vhost_iova_to_vva(dev, vq,
1337 						  descs[avail_idx + i].addr,
1338 						  &lens[i],
1339 						  VHOST_ACCESS_RW);
1340 
1341 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
1342 		if (unlikely(!desc_addrs[i]))
1343 			return -1;
1344 		if (unlikely(lens[i] != descs[avail_idx + i].len))
1345 			return -1;
1346 	}
1347 
1348 	return 0;
1349 }
1350 
1351 static __rte_always_inline void
1352 virtio_dev_rx_batch_packed_copy(struct virtio_net *dev,
1353 			   struct vhost_virtqueue *vq,
1354 			   struct rte_mbuf **pkts,
1355 			   uint64_t *desc_addrs,
1356 			   uint64_t *lens)
1357 {
1358 	uint32_t buf_offset = sizeof(struct virtio_net_hdr_mrg_rxbuf);
1359 	struct virtio_net_hdr_mrg_rxbuf *hdrs[PACKED_BATCH_SIZE];
1360 	struct vring_packed_desc *descs = vq->desc_packed;
1361 	uint16_t avail_idx = vq->last_avail_idx;
1362 	uint16_t ids[PACKED_BATCH_SIZE];
1363 	uint16_t i;
1364 
1365 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
1366 		rte_prefetch0((void *)(uintptr_t)desc_addrs[i]);
1367 		hdrs[i] = (struct virtio_net_hdr_mrg_rxbuf *)
1368 					(uintptr_t)desc_addrs[i];
1369 		lens[i] = pkts[i]->pkt_len +
1370 			sizeof(struct virtio_net_hdr_mrg_rxbuf);
1371 	}
1372 
1373 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
1374 		virtio_enqueue_offload(pkts[i], &hdrs[i]->hdr);
1375 
1376 	vq_inc_last_avail_packed(vq, PACKED_BATCH_SIZE);
1377 
1378 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
1379 		rte_memcpy((void *)(uintptr_t)(desc_addrs[i] + buf_offset),
1380 			   rte_pktmbuf_mtod_offset(pkts[i], void *, 0),
1381 			   pkts[i]->pkt_len);
1382 	}
1383 
1384 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
1385 		vhost_log_cache_write_iova(dev, vq, descs[avail_idx + i].addr,
1386 					   lens[i]);
1387 
1388 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
1389 		ids[i] = descs[avail_idx + i].id;
1390 
1391 	vhost_flush_enqueue_batch_packed(dev, vq, lens, ids);
1392 }
1393 
1394 static __rte_always_inline int
1395 virtio_dev_rx_sync_batch_packed(struct virtio_net *dev,
1396 			   struct vhost_virtqueue *vq,
1397 			   struct rte_mbuf **pkts)
1398 {
1399 	uint64_t desc_addrs[PACKED_BATCH_SIZE];
1400 	uint64_t lens[PACKED_BATCH_SIZE];
1401 
1402 	if (virtio_dev_rx_sync_batch_check(dev, vq, pkts, desc_addrs, lens) == -1)
1403 		return -1;
1404 
1405 	if (vq->shadow_used_idx) {
1406 		do_data_copy_enqueue(dev, vq);
1407 		vhost_flush_enqueue_shadow_packed(dev, vq);
1408 	}
1409 
1410 	virtio_dev_rx_batch_packed_copy(dev, vq, pkts, desc_addrs, lens);
1411 
1412 	return 0;
1413 }
1414 
1415 static __rte_always_inline int16_t
1416 virtio_dev_rx_single_packed(struct virtio_net *dev,
1417 			    struct vhost_virtqueue *vq,
1418 			    struct rte_mbuf *pkt)
1419 {
1420 	struct buf_vector buf_vec[BUF_VECTOR_MAX];
1421 	uint16_t nr_descs = 0;
1422 
1423 	if (unlikely(vhost_enqueue_single_packed(dev, vq, pkt, buf_vec,
1424 						 &nr_descs) < 0)) {
1425 		VHOST_LOG_DATA(DEBUG, "(%s) failed to get enough desc from vring\n",
1426 				dev->ifname);
1427 		return -1;
1428 	}
1429 
1430 	VHOST_LOG_DATA(DEBUG, "(%s) current index %d | end index %d\n",
1431 			dev->ifname, vq->last_avail_idx,
1432 			vq->last_avail_idx + nr_descs);
1433 
1434 	vq_inc_last_avail_packed(vq, nr_descs);
1435 
1436 	return 0;
1437 }
1438 
1439 static __rte_noinline uint32_t
1440 virtio_dev_rx_packed(struct virtio_net *dev,
1441 		     struct vhost_virtqueue *__rte_restrict vq,
1442 		     struct rte_mbuf **__rte_restrict pkts,
1443 		     uint32_t count)
1444 {
1445 	uint32_t pkt_idx = 0;
1446 
1447 	do {
1448 		rte_prefetch0(&vq->desc_packed[vq->last_avail_idx]);
1449 
1450 		if (count - pkt_idx >= PACKED_BATCH_SIZE) {
1451 			if (!virtio_dev_rx_sync_batch_packed(dev, vq,
1452 							&pkts[pkt_idx])) {
1453 				pkt_idx += PACKED_BATCH_SIZE;
1454 				continue;
1455 			}
1456 		}
1457 
1458 		if (virtio_dev_rx_single_packed(dev, vq, pkts[pkt_idx]))
1459 			break;
1460 		pkt_idx++;
1461 
1462 	} while (pkt_idx < count);
1463 
1464 	if (vq->shadow_used_idx) {
1465 		do_data_copy_enqueue(dev, vq);
1466 		vhost_flush_enqueue_shadow_packed(dev, vq);
1467 	}
1468 
1469 	if (pkt_idx)
1470 		vhost_vring_call_packed(dev, vq);
1471 
1472 	return pkt_idx;
1473 }
1474 
1475 static __rte_always_inline uint32_t
1476 virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
1477 	struct rte_mbuf **pkts, uint32_t count)
1478 {
1479 	struct vhost_virtqueue *vq;
1480 	uint32_t nb_tx = 0;
1481 
1482 	VHOST_LOG_DATA(DEBUG, "(%s) %s\n", dev->ifname, __func__);
1483 	if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
1484 		VHOST_LOG_DATA(ERR, "(%s) %s: invalid virtqueue idx %d.\n",
1485 			dev->ifname, __func__, queue_id);
1486 		return 0;
1487 	}
1488 
1489 	vq = dev->virtqueue[queue_id];
1490 
1491 	rte_spinlock_lock(&vq->access_lock);
1492 
1493 	if (unlikely(!vq->enabled))
1494 		goto out_access_unlock;
1495 
1496 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
1497 		vhost_user_iotlb_rd_lock(vq);
1498 
1499 	if (unlikely(!vq->access_ok))
1500 		if (unlikely(vring_translate(dev, vq) < 0))
1501 			goto out;
1502 
1503 	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
1504 	if (count == 0)
1505 		goto out;
1506 
1507 	if (vq_is_packed(dev))
1508 		nb_tx = virtio_dev_rx_packed(dev, vq, pkts, count);
1509 	else
1510 		nb_tx = virtio_dev_rx_split(dev, vq, pkts, count);
1511 
1512 out:
1513 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
1514 		vhost_user_iotlb_rd_unlock(vq);
1515 
1516 out_access_unlock:
1517 	rte_spinlock_unlock(&vq->access_lock);
1518 
1519 	return nb_tx;
1520 }
1521 
1522 uint16_t
1523 rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
1524 	struct rte_mbuf **__rte_restrict pkts, uint16_t count)
1525 {
1526 	struct virtio_net *dev = get_device(vid);
1527 
1528 	if (!dev)
1529 		return 0;
1530 
1531 	if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
1532 		VHOST_LOG_DATA(ERR, "(%s) %s: built-in vhost net backend is disabled.\n",
1533 			dev->ifname, __func__);
1534 		return 0;
1535 	}
1536 
1537 	return virtio_dev_rx(dev, queue_id, pkts, count);
1538 }
1539 
1540 static __rte_always_inline uint16_t
1541 async_get_first_inflight_pkt_idx(struct vhost_virtqueue *vq)
1542 {
1543 	struct vhost_async *async = vq->async;
1544 
1545 	if (async->pkts_idx >= async->pkts_inflight_n)
1546 		return async->pkts_idx - async->pkts_inflight_n;
1547 	else
1548 		return vq->size - async->pkts_inflight_n + async->pkts_idx;
1549 }
1550 
1551 static __rte_always_inline void
1552 store_dma_desc_info_split(struct vring_used_elem *s_ring, struct vring_used_elem *d_ring,
1553 		uint16_t ring_size, uint16_t s_idx, uint16_t d_idx, uint16_t count)
1554 {
1555 	size_t elem_size = sizeof(struct vring_used_elem);
1556 
1557 	if (d_idx + count <= ring_size) {
1558 		rte_memcpy(d_ring + d_idx, s_ring + s_idx, count * elem_size);
1559 	} else {
1560 		uint16_t size = ring_size - d_idx;
1561 
1562 		rte_memcpy(d_ring + d_idx, s_ring + s_idx, size * elem_size);
1563 		rte_memcpy(d_ring, s_ring + s_idx + size, (count - size) * elem_size);
1564 	}
1565 }
1566 
1567 static __rte_always_inline void
1568 store_dma_desc_info_packed(struct vring_used_elem_packed *s_ring,
1569 		struct vring_used_elem_packed *d_ring,
1570 		uint16_t ring_size, uint16_t s_idx, uint16_t d_idx, uint16_t count)
1571 {
1572 	size_t elem_size = sizeof(struct vring_used_elem_packed);
1573 
1574 	if (d_idx + count <= ring_size) {
1575 		rte_memcpy(d_ring + d_idx, s_ring + s_idx, count * elem_size);
1576 	} else {
1577 		uint16_t size = ring_size - d_idx;
1578 
1579 		rte_memcpy(d_ring + d_idx, s_ring + s_idx, size * elem_size);
1580 		rte_memcpy(d_ring, s_ring + s_idx + size, (count - size) * elem_size);
1581 	}
1582 }
1583 
1584 static __rte_noinline uint32_t
1585 virtio_dev_rx_async_submit_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
1586 		uint16_t queue_id, struct rte_mbuf **pkts, uint32_t count,
1587 		int16_t dma_id, uint16_t vchan_id)
1588 {
1589 	struct buf_vector buf_vec[BUF_VECTOR_MAX];
1590 	uint32_t pkt_idx = 0;
1591 	uint16_t num_buffers;
1592 	uint16_t avail_head;
1593 
1594 	struct vhost_async *async = vq->async;
1595 	struct async_inflight_info *pkts_info = async->pkts_info;
1596 	uint32_t pkt_err = 0;
1597 	uint16_t n_xfer;
1598 	uint16_t slot_idx = 0;
1599 
1600 	/*
1601 	 * The ordering between avail index and desc reads need to be enforced.
1602 	 */
1603 	avail_head = __atomic_load_n(&vq->avail->idx, __ATOMIC_ACQUIRE);
1604 
1605 	rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
1606 
1607 	async_iter_reset(async);
1608 
1609 	for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
1610 		uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
1611 		uint16_t nr_vec = 0;
1612 
1613 		if (unlikely(reserve_avail_buf_split(dev, vq, pkt_len, buf_vec,
1614 						&num_buffers, avail_head, &nr_vec) < 0)) {
1615 			VHOST_LOG_DATA(DEBUG, "(%s) failed to get enough desc from vring\n",
1616 					dev->ifname);
1617 			vq->shadow_used_idx -= num_buffers;
1618 			break;
1619 		}
1620 
1621 		VHOST_LOG_DATA(DEBUG, "(%s) current index %d | end index %d\n",
1622 			dev->ifname, vq->last_avail_idx, vq->last_avail_idx + num_buffers);
1623 
1624 		if (mbuf_to_desc(dev, vq, pkts[pkt_idx], buf_vec, nr_vec, num_buffers, true) < 0) {
1625 			vq->shadow_used_idx -= num_buffers;
1626 			break;
1627 		}
1628 
1629 		slot_idx = (async->pkts_idx + pkt_idx) & (vq->size - 1);
1630 		pkts_info[slot_idx].descs = num_buffers;
1631 		pkts_info[slot_idx].mbuf = pkts[pkt_idx];
1632 
1633 		vq->last_avail_idx += num_buffers;
1634 	}
1635 
1636 	if (unlikely(pkt_idx == 0))
1637 		return 0;
1638 
1639 	n_xfer = vhost_async_dma_transfer(dev, vq, dma_id, vchan_id, async->pkts_idx,
1640 			async->iov_iter, pkt_idx);
1641 
1642 	pkt_err = pkt_idx - n_xfer;
1643 	if (unlikely(pkt_err)) {
1644 		uint16_t num_descs = 0;
1645 
1646 		VHOST_LOG_DATA(DEBUG, "(%s) %s: failed to transfer %u packets for queue %u.\n",
1647 				dev->ifname, __func__, pkt_err, queue_id);
1648 
1649 		/* update number of completed packets */
1650 		pkt_idx = n_xfer;
1651 
1652 		/* calculate the sum of descriptors to revert */
1653 		while (pkt_err-- > 0) {
1654 			num_descs += pkts_info[slot_idx & (vq->size - 1)].descs;
1655 			slot_idx--;
1656 		}
1657 
1658 		/* recover shadow used ring and available ring */
1659 		vq->shadow_used_idx -= num_descs;
1660 		vq->last_avail_idx -= num_descs;
1661 	}
1662 
1663 	/* keep used descriptors */
1664 	if (likely(vq->shadow_used_idx)) {
1665 		uint16_t to = async->desc_idx_split & (vq->size - 1);
1666 
1667 		store_dma_desc_info_split(vq->shadow_used_split,
1668 				async->descs_split, vq->size, 0, to,
1669 				vq->shadow_used_idx);
1670 
1671 		async->desc_idx_split += vq->shadow_used_idx;
1672 
1673 		async->pkts_idx += pkt_idx;
1674 		if (async->pkts_idx >= vq->size)
1675 			async->pkts_idx -= vq->size;
1676 
1677 		async->pkts_inflight_n += pkt_idx;
1678 		vq->shadow_used_idx = 0;
1679 	}
1680 
1681 	return pkt_idx;
1682 }
1683 
1684 
1685 static __rte_always_inline int
1686 vhost_enqueue_async_packed(struct virtio_net *dev,
1687 			    struct vhost_virtqueue *vq,
1688 			    struct rte_mbuf *pkt,
1689 			    struct buf_vector *buf_vec,
1690 			    uint16_t *nr_descs,
1691 			    uint16_t *nr_buffers)
1692 {
1693 	uint16_t nr_vec = 0;
1694 	uint16_t avail_idx = vq->last_avail_idx;
1695 	uint16_t max_tries, tries = 0;
1696 	uint16_t buf_id = 0;
1697 	uint32_t len = 0;
1698 	uint16_t desc_count = 0;
1699 	uint32_t size = pkt->pkt_len + sizeof(struct virtio_net_hdr_mrg_rxbuf);
1700 	uint32_t buffer_len[vq->size];
1701 	uint16_t buffer_buf_id[vq->size];
1702 	uint16_t buffer_desc_count[vq->size];
1703 
1704 	if (rxvq_is_mergeable(dev))
1705 		max_tries = vq->size - 1;
1706 	else
1707 		max_tries = 1;
1708 
1709 	while (size > 0) {
1710 		/*
1711 		 * if we tried all available ring items, and still
1712 		 * can't get enough buf, it means something abnormal
1713 		 * happened.
1714 		 */
1715 		if (unlikely(++tries > max_tries))
1716 			return -1;
1717 
1718 		if (unlikely(fill_vec_buf_packed(dev, vq,
1719 						avail_idx, &desc_count,
1720 						buf_vec, &nr_vec,
1721 						&buf_id, &len,
1722 						VHOST_ACCESS_RW) < 0))
1723 			return -1;
1724 
1725 		len = RTE_MIN(len, size);
1726 		size -= len;
1727 
1728 		buffer_len[*nr_buffers] = len;
1729 		buffer_buf_id[*nr_buffers] = buf_id;
1730 		buffer_desc_count[*nr_buffers] = desc_count;
1731 		*nr_buffers += 1;
1732 		*nr_descs += desc_count;
1733 		avail_idx += desc_count;
1734 		if (avail_idx >= vq->size)
1735 			avail_idx -= vq->size;
1736 	}
1737 
1738 	if (unlikely(mbuf_to_desc(dev, vq, pkt, buf_vec, nr_vec, *nr_buffers, true) < 0))
1739 		return -1;
1740 
1741 	vhost_shadow_enqueue_packed(vq, buffer_len, buffer_buf_id, buffer_desc_count, *nr_buffers);
1742 
1743 	return 0;
1744 }
1745 
1746 static __rte_always_inline int16_t
1747 virtio_dev_rx_async_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
1748 			    struct rte_mbuf *pkt, uint16_t *nr_descs, uint16_t *nr_buffers)
1749 {
1750 	struct buf_vector buf_vec[BUF_VECTOR_MAX];
1751 
1752 	if (unlikely(vhost_enqueue_async_packed(dev, vq, pkt, buf_vec,
1753 					nr_descs, nr_buffers) < 0)) {
1754 		VHOST_LOG_DATA(DEBUG, "(%s) failed to get enough desc from vring\n", dev->ifname);
1755 		return -1;
1756 	}
1757 
1758 	VHOST_LOG_DATA(DEBUG, "(%s) current index %d | end index %d\n",
1759 			dev->ifname, vq->last_avail_idx, vq->last_avail_idx + *nr_descs);
1760 
1761 	return 0;
1762 }
1763 
1764 static __rte_always_inline void
1765 dma_error_handler_packed(struct vhost_virtqueue *vq, uint16_t slot_idx,
1766 			uint32_t nr_err, uint32_t *pkt_idx)
1767 {
1768 	uint16_t descs_err = 0;
1769 	uint16_t buffers_err = 0;
1770 	struct async_inflight_info *pkts_info = vq->async->pkts_info;
1771 
1772 	*pkt_idx -= nr_err;
1773 	/* calculate the sum of buffers and descs of DMA-error packets. */
1774 	while (nr_err-- > 0) {
1775 		descs_err += pkts_info[slot_idx % vq->size].descs;
1776 		buffers_err += pkts_info[slot_idx % vq->size].nr_buffers;
1777 		slot_idx--;
1778 	}
1779 
1780 	if (vq->last_avail_idx >= descs_err) {
1781 		vq->last_avail_idx -= descs_err;
1782 	} else {
1783 		vq->last_avail_idx = vq->last_avail_idx + vq->size - descs_err;
1784 		vq->avail_wrap_counter ^= 1;
1785 	}
1786 
1787 	vq->shadow_used_idx -= buffers_err;
1788 }
1789 
1790 static __rte_noinline uint32_t
1791 virtio_dev_rx_async_submit_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
1792 		uint16_t queue_id, struct rte_mbuf **pkts, uint32_t count,
1793 		int16_t dma_id, uint16_t vchan_id)
1794 {
1795 	uint32_t pkt_idx = 0;
1796 	uint32_t remained = count;
1797 	uint16_t n_xfer;
1798 	uint16_t num_buffers;
1799 	uint16_t num_descs;
1800 
1801 	struct vhost_async *async = vq->async;
1802 	struct async_inflight_info *pkts_info = async->pkts_info;
1803 	uint32_t pkt_err = 0;
1804 	uint16_t slot_idx = 0;
1805 
1806 	do {
1807 		rte_prefetch0(&vq->desc_packed[vq->last_avail_idx]);
1808 
1809 		num_buffers = 0;
1810 		num_descs = 0;
1811 		if (unlikely(virtio_dev_rx_async_packed(dev, vq, pkts[pkt_idx],
1812 						&num_descs, &num_buffers) < 0))
1813 			break;
1814 
1815 		slot_idx = (async->pkts_idx + pkt_idx) % vq->size;
1816 
1817 		pkts_info[slot_idx].descs = num_descs;
1818 		pkts_info[slot_idx].nr_buffers = num_buffers;
1819 		pkts_info[slot_idx].mbuf = pkts[pkt_idx];
1820 
1821 		pkt_idx++;
1822 		remained--;
1823 		vq_inc_last_avail_packed(vq, num_descs);
1824 	} while (pkt_idx < count);
1825 
1826 	if (unlikely(pkt_idx == 0))
1827 		return 0;
1828 
1829 	n_xfer = vhost_async_dma_transfer(dev, vq, dma_id, vchan_id, async->pkts_idx,
1830 			async->iov_iter, pkt_idx);
1831 
1832 	async_iter_reset(async);
1833 
1834 	pkt_err = pkt_idx - n_xfer;
1835 	if (unlikely(pkt_err)) {
1836 		VHOST_LOG_DATA(DEBUG, "(%s) %s: failed to transfer %u packets for queue %u.\n",
1837 				dev->ifname, __func__, pkt_err, queue_id);
1838 		dma_error_handler_packed(vq, slot_idx, pkt_err, &pkt_idx);
1839 	}
1840 
1841 	if (likely(vq->shadow_used_idx)) {
1842 		/* keep used descriptors. */
1843 		store_dma_desc_info_packed(vq->shadow_used_packed, async->buffers_packed,
1844 					vq->size, 0, async->buffer_idx_packed,
1845 					vq->shadow_used_idx);
1846 
1847 		async->buffer_idx_packed += vq->shadow_used_idx;
1848 		if (async->buffer_idx_packed >= vq->size)
1849 			async->buffer_idx_packed -= vq->size;
1850 
1851 		async->pkts_idx += pkt_idx;
1852 		if (async->pkts_idx >= vq->size)
1853 			async->pkts_idx -= vq->size;
1854 
1855 		vq->shadow_used_idx = 0;
1856 		async->pkts_inflight_n += pkt_idx;
1857 	}
1858 
1859 	return pkt_idx;
1860 }
1861 
1862 static __rte_always_inline void
1863 write_back_completed_descs_split(struct vhost_virtqueue *vq, uint16_t n_descs)
1864 {
1865 	struct vhost_async *async = vq->async;
1866 	uint16_t nr_left = n_descs;
1867 	uint16_t nr_copy;
1868 	uint16_t to, from;
1869 
1870 	do {
1871 		from = async->last_desc_idx_split & (vq->size - 1);
1872 		nr_copy = nr_left + from <= vq->size ? nr_left : vq->size - from;
1873 		to = vq->last_used_idx & (vq->size - 1);
1874 
1875 		if (to + nr_copy <= vq->size) {
1876 			rte_memcpy(&vq->used->ring[to], &async->descs_split[from],
1877 					nr_copy * sizeof(struct vring_used_elem));
1878 		} else {
1879 			uint16_t size = vq->size - to;
1880 
1881 			rte_memcpy(&vq->used->ring[to], &async->descs_split[from],
1882 					size * sizeof(struct vring_used_elem));
1883 			rte_memcpy(&vq->used->ring[0], &async->descs_split[from + size],
1884 					(nr_copy - size) * sizeof(struct vring_used_elem));
1885 		}
1886 
1887 		async->last_desc_idx_split += nr_copy;
1888 		vq->last_used_idx += nr_copy;
1889 		nr_left -= nr_copy;
1890 	} while (nr_left > 0);
1891 }
1892 
1893 static __rte_always_inline void
1894 write_back_completed_descs_packed(struct vhost_virtqueue *vq,
1895 				uint16_t n_buffers)
1896 {
1897 	struct vhost_async *async = vq->async;
1898 	uint16_t from = async->last_buffer_idx_packed;
1899 	uint16_t used_idx = vq->last_used_idx;
1900 	uint16_t head_idx = vq->last_used_idx;
1901 	uint16_t head_flags = 0;
1902 	uint16_t i;
1903 
1904 	/* Split loop in two to save memory barriers */
1905 	for (i = 0; i < n_buffers; i++) {
1906 		vq->desc_packed[used_idx].id = async->buffers_packed[from].id;
1907 		vq->desc_packed[used_idx].len = async->buffers_packed[from].len;
1908 
1909 		used_idx += async->buffers_packed[from].count;
1910 		if (used_idx >= vq->size)
1911 			used_idx -= vq->size;
1912 
1913 		from++;
1914 		if (from >= vq->size)
1915 			from = 0;
1916 	}
1917 
1918 	/* The ordering for storing desc flags needs to be enforced. */
1919 	rte_atomic_thread_fence(__ATOMIC_RELEASE);
1920 
1921 	from = async->last_buffer_idx_packed;
1922 
1923 	for (i = 0; i < n_buffers; i++) {
1924 		uint16_t flags;
1925 
1926 		if (async->buffers_packed[from].len)
1927 			flags = VRING_DESC_F_WRITE;
1928 		else
1929 			flags = 0;
1930 
1931 		if (vq->used_wrap_counter) {
1932 			flags |= VRING_DESC_F_USED;
1933 			flags |= VRING_DESC_F_AVAIL;
1934 		} else {
1935 			flags &= ~VRING_DESC_F_USED;
1936 			flags &= ~VRING_DESC_F_AVAIL;
1937 		}
1938 
1939 		if (i > 0) {
1940 			vq->desc_packed[vq->last_used_idx].flags = flags;
1941 		} else {
1942 			head_idx = vq->last_used_idx;
1943 			head_flags = flags;
1944 		}
1945 
1946 		vq_inc_last_used_packed(vq, async->buffers_packed[from].count);
1947 
1948 		from++;
1949 		if (from == vq->size)
1950 			from = 0;
1951 	}
1952 
1953 	vq->desc_packed[head_idx].flags = head_flags;
1954 	async->last_buffer_idx_packed = from;
1955 }
1956 
1957 static __rte_always_inline uint16_t
1958 vhost_poll_enqueue_completed(struct virtio_net *dev, uint16_t queue_id,
1959 		struct rte_mbuf **pkts, uint16_t count, int16_t dma_id,
1960 		uint16_t vchan_id)
1961 {
1962 	struct vhost_virtqueue *vq = dev->virtqueue[queue_id];
1963 	struct vhost_async *async = vq->async;
1964 	struct async_inflight_info *pkts_info = async->pkts_info;
1965 	uint16_t nr_cpl_pkts = 0;
1966 	uint16_t n_descs = 0, n_buffers = 0;
1967 	uint16_t start_idx, from, i;
1968 
1969 	/* Check completed copies for the given DMA vChannel */
1970 	vhost_async_dma_check_completed(dev, dma_id, vchan_id, VHOST_DMA_MAX_COPY_COMPLETE);
1971 
1972 	start_idx = async_get_first_inflight_pkt_idx(vq);
1973 	/**
1974 	 * Calculate the number of copy completed packets.
1975 	 * Note that there may be completed packets even if
1976 	 * no copies are reported done by the given DMA vChannel,
1977 	 * as it's possible that a virtqueue uses multiple DMA
1978 	 * vChannels.
1979 	 */
1980 	from = start_idx;
1981 	while (vq->async->pkts_cmpl_flag[from] && count--) {
1982 		vq->async->pkts_cmpl_flag[from] = false;
1983 		from++;
1984 		if (from >= vq->size)
1985 			from -= vq->size;
1986 		nr_cpl_pkts++;
1987 	}
1988 
1989 	if (nr_cpl_pkts == 0)
1990 		return 0;
1991 
1992 	for (i = 0; i < nr_cpl_pkts; i++) {
1993 		from = (start_idx + i) % vq->size;
1994 		/* Only used with packed ring */
1995 		n_buffers += pkts_info[from].nr_buffers;
1996 		/* Only used with split ring */
1997 		n_descs += pkts_info[from].descs;
1998 		pkts[i] = pkts_info[from].mbuf;
1999 	}
2000 
2001 	async->pkts_inflight_n -= nr_cpl_pkts;
2002 
2003 	if (likely(vq->enabled && vq->access_ok)) {
2004 		if (vq_is_packed(dev)) {
2005 			write_back_completed_descs_packed(vq, n_buffers);
2006 			vhost_vring_call_packed(dev, vq);
2007 		} else {
2008 			write_back_completed_descs_split(vq, n_descs);
2009 			__atomic_add_fetch(&vq->used->idx, n_descs, __ATOMIC_RELEASE);
2010 			vhost_vring_call_split(dev, vq);
2011 		}
2012 	} else {
2013 		if (vq_is_packed(dev)) {
2014 			async->last_buffer_idx_packed += n_buffers;
2015 			if (async->last_buffer_idx_packed >= vq->size)
2016 				async->last_buffer_idx_packed -= vq->size;
2017 		} else {
2018 			async->last_desc_idx_split += n_descs;
2019 		}
2020 	}
2021 
2022 	return nr_cpl_pkts;
2023 }
2024 
2025 uint16_t
2026 rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
2027 		struct rte_mbuf **pkts, uint16_t count, int16_t dma_id,
2028 		uint16_t vchan_id)
2029 {
2030 	struct virtio_net *dev = get_device(vid);
2031 	struct vhost_virtqueue *vq;
2032 	uint16_t n_pkts_cpl = 0;
2033 
2034 	if (unlikely(!dev))
2035 		return 0;
2036 
2037 	VHOST_LOG_DATA(DEBUG, "(%s) %s\n", dev->ifname, __func__);
2038 	if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
2039 		VHOST_LOG_DATA(ERR, "(%s) %s: invalid virtqueue idx %d.\n",
2040 			dev->ifname, __func__, queue_id);
2041 		return 0;
2042 	}
2043 
2044 	if (unlikely(!dma_copy_track[dma_id].vchans ||
2045 				!dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr)) {
2046 		VHOST_LOG_DATA(ERR, "(%s) %s: invalid channel %d:%u.\n", dev->ifname, __func__,
2047 			       dma_id, vchan_id);
2048 		return 0;
2049 	}
2050 
2051 	vq = dev->virtqueue[queue_id];
2052 
2053 	if (!rte_spinlock_trylock(&vq->access_lock)) {
2054 		VHOST_LOG_DATA(DEBUG, "(%s) %s: virtqueue %u is busy.\n", dev->ifname, __func__,
2055 				queue_id);
2056 		return 0;
2057 	}
2058 
2059 	if (unlikely(!vq->async)) {
2060 		VHOST_LOG_DATA(ERR, "(%s) %s: async not registered for virtqueue %d.\n",
2061 				dev->ifname, __func__, queue_id);
2062 		goto out;
2063 	}
2064 
2065 	n_pkts_cpl = vhost_poll_enqueue_completed(dev, queue_id, pkts, count, dma_id, vchan_id);
2066 
2067 out:
2068 	rte_spinlock_unlock(&vq->access_lock);
2069 
2070 	return n_pkts_cpl;
2071 }
2072 
2073 uint16_t
2074 rte_vhost_clear_queue_thread_unsafe(int vid, uint16_t queue_id,
2075 		struct rte_mbuf **pkts, uint16_t count, int16_t dma_id,
2076 		uint16_t vchan_id)
2077 {
2078 	struct virtio_net *dev = get_device(vid);
2079 	struct vhost_virtqueue *vq;
2080 	uint16_t n_pkts_cpl = 0;
2081 
2082 	if (!dev)
2083 		return 0;
2084 
2085 	VHOST_LOG_DATA(DEBUG, "(%s) %s\n", dev->ifname, __func__);
2086 	if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
2087 		VHOST_LOG_DATA(ERR, "(%s) %s: invalid virtqueue idx %d.\n",
2088 			dev->ifname, __func__, queue_id);
2089 		return 0;
2090 	}
2091 
2092 	vq = dev->virtqueue[queue_id];
2093 
2094 	if (unlikely(!vq->async)) {
2095 		VHOST_LOG_DATA(ERR, "(%s) %s: async not registered for queue id %d.\n",
2096 			dev->ifname, __func__, queue_id);
2097 		return 0;
2098 	}
2099 
2100 	if (unlikely(!dma_copy_track[dma_id].vchans ||
2101 				!dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr)) {
2102 		VHOST_LOG_DATA(ERR, "(%s) %s: invalid channel %d:%u.\n", dev->ifname, __func__,
2103 				dma_id, vchan_id);
2104 		return 0;
2105 	}
2106 
2107 	n_pkts_cpl = vhost_poll_enqueue_completed(dev, queue_id, pkts, count, dma_id, vchan_id);
2108 
2109 	return n_pkts_cpl;
2110 }
2111 
2112 static __rte_always_inline uint32_t
2113 virtio_dev_rx_async_submit(struct virtio_net *dev, uint16_t queue_id,
2114 	struct rte_mbuf **pkts, uint32_t count, int16_t dma_id, uint16_t vchan_id)
2115 {
2116 	struct vhost_virtqueue *vq;
2117 	uint32_t nb_tx = 0;
2118 
2119 	VHOST_LOG_DATA(DEBUG, "(%s) %s\n", dev->ifname, __func__);
2120 	if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
2121 		VHOST_LOG_DATA(ERR, "(%s) %s: invalid virtqueue idx %d.\n",
2122 			dev->ifname, __func__, queue_id);
2123 		return 0;
2124 	}
2125 
2126 	if (unlikely(!dma_copy_track[dma_id].vchans ||
2127 				!dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr)) {
2128 		VHOST_LOG_DATA(ERR, "(%s) %s: invalid channel %d:%u.\n", dev->ifname, __func__,
2129 			       dma_id, vchan_id);
2130 		return 0;
2131 	}
2132 
2133 	vq = dev->virtqueue[queue_id];
2134 
2135 	rte_spinlock_lock(&vq->access_lock);
2136 
2137 	if (unlikely(!vq->enabled || !vq->async))
2138 		goto out_access_unlock;
2139 
2140 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
2141 		vhost_user_iotlb_rd_lock(vq);
2142 
2143 	if (unlikely(!vq->access_ok))
2144 		if (unlikely(vring_translate(dev, vq) < 0))
2145 			goto out;
2146 
2147 	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
2148 	if (count == 0)
2149 		goto out;
2150 
2151 	if (vq_is_packed(dev))
2152 		nb_tx = virtio_dev_rx_async_submit_packed(dev, vq, queue_id,
2153 				pkts, count, dma_id, vchan_id);
2154 	else
2155 		nb_tx = virtio_dev_rx_async_submit_split(dev, vq, queue_id,
2156 				pkts, count, dma_id, vchan_id);
2157 
2158 out:
2159 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
2160 		vhost_user_iotlb_rd_unlock(vq);
2161 
2162 out_access_unlock:
2163 	rte_spinlock_unlock(&vq->access_lock);
2164 
2165 	return nb_tx;
2166 }
2167 
2168 uint16_t
2169 rte_vhost_submit_enqueue_burst(int vid, uint16_t queue_id,
2170 		struct rte_mbuf **pkts, uint16_t count, int16_t dma_id,
2171 		uint16_t vchan_id)
2172 {
2173 	struct virtio_net *dev = get_device(vid);
2174 
2175 	if (!dev)
2176 		return 0;
2177 
2178 	if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
2179 		VHOST_LOG_DATA(ERR, "(%s) %s: built-in vhost net backend is disabled.\n",
2180 			dev->ifname, __func__);
2181 		return 0;
2182 	}
2183 
2184 	return virtio_dev_rx_async_submit(dev, queue_id, pkts, count, dma_id, vchan_id);
2185 }
2186 
2187 static inline bool
2188 virtio_net_with_host_offload(struct virtio_net *dev)
2189 {
2190 	if (dev->features &
2191 			((1ULL << VIRTIO_NET_F_CSUM) |
2192 			 (1ULL << VIRTIO_NET_F_HOST_ECN) |
2193 			 (1ULL << VIRTIO_NET_F_HOST_TSO4) |
2194 			 (1ULL << VIRTIO_NET_F_HOST_TSO6) |
2195 			 (1ULL << VIRTIO_NET_F_HOST_UFO)))
2196 		return true;
2197 
2198 	return false;
2199 }
2200 
2201 static int
2202 parse_headers(struct rte_mbuf *m, uint8_t *l4_proto)
2203 {
2204 	struct rte_ipv4_hdr *ipv4_hdr;
2205 	struct rte_ipv6_hdr *ipv6_hdr;
2206 	struct rte_ether_hdr *eth_hdr;
2207 	uint16_t ethertype;
2208 	uint16_t data_len = rte_pktmbuf_data_len(m);
2209 
2210 	if (data_len < sizeof(struct rte_ether_hdr))
2211 		return -EINVAL;
2212 
2213 	eth_hdr = rte_pktmbuf_mtod(m, struct rte_ether_hdr *);
2214 
2215 	m->l2_len = sizeof(struct rte_ether_hdr);
2216 	ethertype = rte_be_to_cpu_16(eth_hdr->ether_type);
2217 
2218 	if (ethertype == RTE_ETHER_TYPE_VLAN) {
2219 		if (data_len < sizeof(struct rte_ether_hdr) +
2220 				sizeof(struct rte_vlan_hdr))
2221 			goto error;
2222 
2223 		struct rte_vlan_hdr *vlan_hdr =
2224 			(struct rte_vlan_hdr *)(eth_hdr + 1);
2225 
2226 		m->l2_len += sizeof(struct rte_vlan_hdr);
2227 		ethertype = rte_be_to_cpu_16(vlan_hdr->eth_proto);
2228 	}
2229 
2230 	switch (ethertype) {
2231 	case RTE_ETHER_TYPE_IPV4:
2232 		if (data_len < m->l2_len + sizeof(struct rte_ipv4_hdr))
2233 			goto error;
2234 		ipv4_hdr = rte_pktmbuf_mtod_offset(m, struct rte_ipv4_hdr *,
2235 				m->l2_len);
2236 		m->l3_len = rte_ipv4_hdr_len(ipv4_hdr);
2237 		if (data_len < m->l2_len + m->l3_len)
2238 			goto error;
2239 		m->ol_flags |= RTE_MBUF_F_TX_IPV4;
2240 		*l4_proto = ipv4_hdr->next_proto_id;
2241 		break;
2242 	case RTE_ETHER_TYPE_IPV6:
2243 		if (data_len < m->l2_len + sizeof(struct rte_ipv6_hdr))
2244 			goto error;
2245 		ipv6_hdr = rte_pktmbuf_mtod_offset(m, struct rte_ipv6_hdr *,
2246 				m->l2_len);
2247 		m->l3_len = sizeof(struct rte_ipv6_hdr);
2248 		m->ol_flags |= RTE_MBUF_F_TX_IPV6;
2249 		*l4_proto = ipv6_hdr->proto;
2250 		break;
2251 	default:
2252 		/* a valid L3 header is needed for further L4 parsing */
2253 		goto error;
2254 	}
2255 
2256 	/* both CSUM and GSO need a valid L4 header */
2257 	switch (*l4_proto) {
2258 	case IPPROTO_TCP:
2259 		if (data_len < m->l2_len + m->l3_len +
2260 				sizeof(struct rte_tcp_hdr))
2261 			goto error;
2262 		break;
2263 	case IPPROTO_UDP:
2264 		if (data_len < m->l2_len + m->l3_len +
2265 				sizeof(struct rte_udp_hdr))
2266 			goto error;
2267 		break;
2268 	case IPPROTO_SCTP:
2269 		if (data_len < m->l2_len + m->l3_len +
2270 				sizeof(struct rte_sctp_hdr))
2271 			goto error;
2272 		break;
2273 	default:
2274 		goto error;
2275 	}
2276 
2277 	return 0;
2278 
2279 error:
2280 	m->l2_len = 0;
2281 	m->l3_len = 0;
2282 	m->ol_flags = 0;
2283 	return -EINVAL;
2284 }
2285 
2286 static __rte_always_inline void
2287 vhost_dequeue_offload_legacy(struct virtio_net *dev, struct virtio_net_hdr *hdr,
2288 		struct rte_mbuf *m)
2289 {
2290 	uint8_t l4_proto = 0;
2291 	struct rte_tcp_hdr *tcp_hdr = NULL;
2292 	uint16_t tcp_len;
2293 	uint16_t data_len = rte_pktmbuf_data_len(m);
2294 
2295 	if (parse_headers(m, &l4_proto) < 0)
2296 		return;
2297 
2298 	if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) {
2299 		if (hdr->csum_start == (m->l2_len + m->l3_len)) {
2300 			switch (hdr->csum_offset) {
2301 			case (offsetof(struct rte_tcp_hdr, cksum)):
2302 				if (l4_proto != IPPROTO_TCP)
2303 					goto error;
2304 				m->ol_flags |= RTE_MBUF_F_TX_TCP_CKSUM;
2305 				break;
2306 			case (offsetof(struct rte_udp_hdr, dgram_cksum)):
2307 				if (l4_proto != IPPROTO_UDP)
2308 					goto error;
2309 				m->ol_flags |= RTE_MBUF_F_TX_UDP_CKSUM;
2310 				break;
2311 			case (offsetof(struct rte_sctp_hdr, cksum)):
2312 				if (l4_proto != IPPROTO_SCTP)
2313 					goto error;
2314 				m->ol_flags |= RTE_MBUF_F_TX_SCTP_CKSUM;
2315 				break;
2316 			default:
2317 				goto error;
2318 			}
2319 		} else {
2320 			goto error;
2321 		}
2322 	}
2323 
2324 	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
2325 		switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
2326 		case VIRTIO_NET_HDR_GSO_TCPV4:
2327 		case VIRTIO_NET_HDR_GSO_TCPV6:
2328 			if (l4_proto != IPPROTO_TCP)
2329 				goto error;
2330 			tcp_hdr = rte_pktmbuf_mtod_offset(m,
2331 					struct rte_tcp_hdr *,
2332 					m->l2_len + m->l3_len);
2333 			tcp_len = (tcp_hdr->data_off & 0xf0) >> 2;
2334 			if (data_len < m->l2_len + m->l3_len + tcp_len)
2335 				goto error;
2336 			m->ol_flags |= RTE_MBUF_F_TX_TCP_SEG;
2337 			m->tso_segsz = hdr->gso_size;
2338 			m->l4_len = tcp_len;
2339 			break;
2340 		case VIRTIO_NET_HDR_GSO_UDP:
2341 			if (l4_proto != IPPROTO_UDP)
2342 				goto error;
2343 			m->ol_flags |= RTE_MBUF_F_TX_UDP_SEG;
2344 			m->tso_segsz = hdr->gso_size;
2345 			m->l4_len = sizeof(struct rte_udp_hdr);
2346 			break;
2347 		default:
2348 			VHOST_LOG_DATA(WARNING, "(%s) unsupported gso type %u.\n",
2349 					dev->ifname, hdr->gso_type);
2350 			goto error;
2351 		}
2352 	}
2353 	return;
2354 
2355 error:
2356 	m->l2_len = 0;
2357 	m->l3_len = 0;
2358 	m->ol_flags = 0;
2359 }
2360 
2361 static __rte_always_inline void
2362 vhost_dequeue_offload(struct virtio_net *dev, struct virtio_net_hdr *hdr,
2363 		struct rte_mbuf *m, bool legacy_ol_flags)
2364 {
2365 	struct rte_net_hdr_lens hdr_lens;
2366 	int l4_supported = 0;
2367 	uint32_t ptype;
2368 
2369 	if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
2370 		return;
2371 
2372 	if (legacy_ol_flags) {
2373 		vhost_dequeue_offload_legacy(dev, hdr, m);
2374 		return;
2375 	}
2376 
2377 	m->ol_flags |= RTE_MBUF_F_RX_IP_CKSUM_UNKNOWN;
2378 
2379 	ptype = rte_net_get_ptype(m, &hdr_lens, RTE_PTYPE_ALL_MASK);
2380 	m->packet_type = ptype;
2381 	if ((ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_TCP ||
2382 	    (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_UDP ||
2383 	    (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_SCTP)
2384 		l4_supported = 1;
2385 
2386 	/* According to Virtio 1.1 spec, the device only needs to look at
2387 	 * VIRTIO_NET_HDR_F_NEEDS_CSUM in the packet transmission path.
2388 	 * This differs from the processing incoming packets path where the
2389 	 * driver could rely on VIRTIO_NET_HDR_F_DATA_VALID flag set by the
2390 	 * device.
2391 	 *
2392 	 * 5.1.6.2.1 Driver Requirements: Packet Transmission
2393 	 * The driver MUST NOT set the VIRTIO_NET_HDR_F_DATA_VALID and
2394 	 * VIRTIO_NET_HDR_F_RSC_INFO bits in flags.
2395 	 *
2396 	 * 5.1.6.2.2 Device Requirements: Packet Transmission
2397 	 * The device MUST ignore flag bits that it does not recognize.
2398 	 */
2399 	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
2400 		uint32_t hdrlen;
2401 
2402 		hdrlen = hdr_lens.l2_len + hdr_lens.l3_len + hdr_lens.l4_len;
2403 		if (hdr->csum_start <= hdrlen && l4_supported != 0) {
2404 			m->ol_flags |= RTE_MBUF_F_RX_L4_CKSUM_NONE;
2405 		} else {
2406 			/* Unknown proto or tunnel, do sw cksum. We can assume
2407 			 * the cksum field is in the first segment since the
2408 			 * buffers we provided to the host are large enough.
2409 			 * In case of SCTP, this will be wrong since it's a CRC
2410 			 * but there's nothing we can do.
2411 			 */
2412 			uint16_t csum = 0, off;
2413 
2414 			if (rte_raw_cksum_mbuf(m, hdr->csum_start,
2415 					rte_pktmbuf_pkt_len(m) - hdr->csum_start, &csum) < 0)
2416 				return;
2417 			if (likely(csum != 0xffff))
2418 				csum = ~csum;
2419 			off = hdr->csum_offset + hdr->csum_start;
2420 			if (rte_pktmbuf_data_len(m) >= off + 1)
2421 				*rte_pktmbuf_mtod_offset(m, uint16_t *, off) = csum;
2422 		}
2423 	}
2424 
2425 	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
2426 		if (hdr->gso_size == 0)
2427 			return;
2428 
2429 		switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
2430 		case VIRTIO_NET_HDR_GSO_TCPV4:
2431 		case VIRTIO_NET_HDR_GSO_TCPV6:
2432 			if ((ptype & RTE_PTYPE_L4_MASK) != RTE_PTYPE_L4_TCP)
2433 				break;
2434 			m->ol_flags |= RTE_MBUF_F_RX_LRO | RTE_MBUF_F_RX_L4_CKSUM_NONE;
2435 			m->tso_segsz = hdr->gso_size;
2436 			break;
2437 		case VIRTIO_NET_HDR_GSO_UDP:
2438 			if ((ptype & RTE_PTYPE_L4_MASK) != RTE_PTYPE_L4_UDP)
2439 				break;
2440 			m->ol_flags |= RTE_MBUF_F_RX_LRO | RTE_MBUF_F_RX_L4_CKSUM_NONE;
2441 			m->tso_segsz = hdr->gso_size;
2442 			break;
2443 		default:
2444 			break;
2445 		}
2446 	}
2447 }
2448 
2449 static __rte_noinline void
2450 copy_vnet_hdr_from_desc(struct virtio_net_hdr *hdr,
2451 		struct buf_vector *buf_vec)
2452 {
2453 	uint64_t len;
2454 	uint64_t remain = sizeof(struct virtio_net_hdr);
2455 	uint64_t src;
2456 	uint64_t dst = (uint64_t)(uintptr_t)hdr;
2457 
2458 	while (remain) {
2459 		len = RTE_MIN(remain, buf_vec->buf_len);
2460 		src = buf_vec->buf_addr;
2461 		rte_memcpy((void *)(uintptr_t)dst,
2462 				(void *)(uintptr_t)src, len);
2463 
2464 		remain -= len;
2465 		dst += len;
2466 		buf_vec++;
2467 	}
2468 }
2469 
2470 static __rte_always_inline int
2471 copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
2472 		  struct buf_vector *buf_vec, uint16_t nr_vec,
2473 		  struct rte_mbuf *m, struct rte_mempool *mbuf_pool,
2474 		  bool legacy_ol_flags)
2475 {
2476 	uint32_t buf_avail, buf_offset;
2477 	uint64_t buf_addr, buf_len;
2478 	uint32_t mbuf_avail, mbuf_offset;
2479 	uint32_t cpy_len;
2480 	struct rte_mbuf *cur = m, *prev = m;
2481 	struct virtio_net_hdr tmp_hdr;
2482 	struct virtio_net_hdr *hdr = NULL;
2483 	/* A counter to avoid desc dead loop chain */
2484 	uint16_t vec_idx = 0;
2485 	struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
2486 	int error = 0;
2487 
2488 	buf_addr = buf_vec[vec_idx].buf_addr;
2489 	buf_len = buf_vec[vec_idx].buf_len;
2490 
2491 	if (unlikely(buf_len < dev->vhost_hlen && nr_vec <= 1)) {
2492 		error = -1;
2493 		goto out;
2494 	}
2495 
2496 	if (virtio_net_with_host_offload(dev)) {
2497 		if (unlikely(buf_len < sizeof(struct virtio_net_hdr))) {
2498 			/*
2499 			 * No luck, the virtio-net header doesn't fit
2500 			 * in a contiguous virtual area.
2501 			 */
2502 			copy_vnet_hdr_from_desc(&tmp_hdr, buf_vec);
2503 			hdr = &tmp_hdr;
2504 		} else {
2505 			hdr = (struct virtio_net_hdr *)((uintptr_t)buf_addr);
2506 		}
2507 	}
2508 
2509 	/*
2510 	 * A virtio driver normally uses at least 2 desc buffers
2511 	 * for Tx: the first for storing the header, and others
2512 	 * for storing the data.
2513 	 */
2514 	if (unlikely(buf_len < dev->vhost_hlen)) {
2515 		buf_offset = dev->vhost_hlen - buf_len;
2516 		vec_idx++;
2517 		buf_addr = buf_vec[vec_idx].buf_addr;
2518 		buf_len = buf_vec[vec_idx].buf_len;
2519 		buf_avail  = buf_len - buf_offset;
2520 	} else if (buf_len == dev->vhost_hlen) {
2521 		if (unlikely(++vec_idx >= nr_vec))
2522 			goto out;
2523 		buf_addr = buf_vec[vec_idx].buf_addr;
2524 		buf_len = buf_vec[vec_idx].buf_len;
2525 
2526 		buf_offset = 0;
2527 		buf_avail = buf_len;
2528 	} else {
2529 		buf_offset = dev->vhost_hlen;
2530 		buf_avail = buf_vec[vec_idx].buf_len - dev->vhost_hlen;
2531 	}
2532 
2533 	PRINT_PACKET(dev,
2534 			(uintptr_t)(buf_addr + buf_offset),
2535 			(uint32_t)buf_avail, 0);
2536 
2537 	mbuf_offset = 0;
2538 	mbuf_avail  = m->buf_len - RTE_PKTMBUF_HEADROOM;
2539 	while (1) {
2540 		cpy_len = RTE_MIN(buf_avail, mbuf_avail);
2541 
2542 		if (likely(cpy_len > MAX_BATCH_LEN ||
2543 					vq->batch_copy_nb_elems >= vq->size ||
2544 					(hdr && cur == m))) {
2545 			rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
2546 						mbuf_offset),
2547 					(void *)((uintptr_t)(buf_addr +
2548 							buf_offset)), cpy_len);
2549 		} else {
2550 			batch_copy[vq->batch_copy_nb_elems].dst =
2551 				rte_pktmbuf_mtod_offset(cur, void *,
2552 						mbuf_offset);
2553 			batch_copy[vq->batch_copy_nb_elems].src =
2554 				(void *)((uintptr_t)(buf_addr + buf_offset));
2555 			batch_copy[vq->batch_copy_nb_elems].len = cpy_len;
2556 			vq->batch_copy_nb_elems++;
2557 		}
2558 
2559 		mbuf_avail  -= cpy_len;
2560 		mbuf_offset += cpy_len;
2561 		buf_avail -= cpy_len;
2562 		buf_offset += cpy_len;
2563 
2564 		/* This buf reaches to its end, get the next one */
2565 		if (buf_avail == 0) {
2566 			if (++vec_idx >= nr_vec)
2567 				break;
2568 
2569 			buf_addr = buf_vec[vec_idx].buf_addr;
2570 			buf_len = buf_vec[vec_idx].buf_len;
2571 
2572 			buf_offset = 0;
2573 			buf_avail  = buf_len;
2574 
2575 			PRINT_PACKET(dev, (uintptr_t)buf_addr,
2576 					(uint32_t)buf_avail, 0);
2577 		}
2578 
2579 		/*
2580 		 * This mbuf reaches to its end, get a new one
2581 		 * to hold more data.
2582 		 */
2583 		if (mbuf_avail == 0) {
2584 			cur = rte_pktmbuf_alloc(mbuf_pool);
2585 			if (unlikely(cur == NULL)) {
2586 				VHOST_LOG_DATA(ERR, "(%s) failed to allocate memory for mbuf.\n",
2587 						dev->ifname);
2588 				error = -1;
2589 				goto out;
2590 			}
2591 
2592 			prev->next = cur;
2593 			prev->data_len = mbuf_offset;
2594 			m->nb_segs += 1;
2595 			m->pkt_len += mbuf_offset;
2596 			prev = cur;
2597 
2598 			mbuf_offset = 0;
2599 			mbuf_avail  = cur->buf_len - RTE_PKTMBUF_HEADROOM;
2600 		}
2601 	}
2602 
2603 	prev->data_len = mbuf_offset;
2604 	m->pkt_len    += mbuf_offset;
2605 
2606 	if (hdr)
2607 		vhost_dequeue_offload(dev, hdr, m, legacy_ol_flags);
2608 
2609 out:
2610 
2611 	return error;
2612 }
2613 
2614 static void
2615 virtio_dev_extbuf_free(void *addr __rte_unused, void *opaque)
2616 {
2617 	rte_free(opaque);
2618 }
2619 
2620 static int
2621 virtio_dev_extbuf_alloc(struct virtio_net *dev, struct rte_mbuf *pkt, uint32_t size)
2622 {
2623 	struct rte_mbuf_ext_shared_info *shinfo = NULL;
2624 	uint32_t total_len = RTE_PKTMBUF_HEADROOM + size;
2625 	uint16_t buf_len;
2626 	rte_iova_t iova;
2627 	void *buf;
2628 
2629 	total_len += sizeof(*shinfo) + sizeof(uintptr_t);
2630 	total_len = RTE_ALIGN_CEIL(total_len, sizeof(uintptr_t));
2631 
2632 	if (unlikely(total_len > UINT16_MAX))
2633 		return -ENOSPC;
2634 
2635 	buf_len = total_len;
2636 	buf = rte_malloc(NULL, buf_len, RTE_CACHE_LINE_SIZE);
2637 	if (unlikely(buf == NULL))
2638 		return -ENOMEM;
2639 
2640 	/* Initialize shinfo */
2641 	shinfo = rte_pktmbuf_ext_shinfo_init_helper(buf, &buf_len,
2642 						virtio_dev_extbuf_free, buf);
2643 	if (unlikely(shinfo == NULL)) {
2644 		rte_free(buf);
2645 		VHOST_LOG_DATA(ERR, "(%s) failed to init shinfo\n", dev->ifname);
2646 		return -1;
2647 	}
2648 
2649 	iova = rte_malloc_virt2iova(buf);
2650 	rte_pktmbuf_attach_extbuf(pkt, buf, iova, buf_len, shinfo);
2651 	rte_pktmbuf_reset_headroom(pkt);
2652 
2653 	return 0;
2654 }
2655 
2656 /*
2657  * Prepare a host supported pktmbuf.
2658  */
2659 static __rte_always_inline int
2660 virtio_dev_pktmbuf_prep(struct virtio_net *dev, struct rte_mbuf *pkt,
2661 			 uint32_t data_len)
2662 {
2663 	if (rte_pktmbuf_tailroom(pkt) >= data_len)
2664 		return 0;
2665 
2666 	/* attach an external buffer if supported */
2667 	if (dev->extbuf && !virtio_dev_extbuf_alloc(dev, pkt, data_len))
2668 		return 0;
2669 
2670 	/* check if chained buffers are allowed */
2671 	if (!dev->linearbuf)
2672 		return 0;
2673 
2674 	return -1;
2675 }
2676 
2677 __rte_always_inline
2678 static uint16_t
2679 virtio_dev_tx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
2680 	struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count,
2681 	bool legacy_ol_flags)
2682 {
2683 	uint16_t i;
2684 	uint16_t free_entries;
2685 	uint16_t dropped = 0;
2686 	static bool allocerr_warned;
2687 
2688 	/*
2689 	 * The ordering between avail index and
2690 	 * desc reads needs to be enforced.
2691 	 */
2692 	free_entries = __atomic_load_n(&vq->avail->idx, __ATOMIC_ACQUIRE) -
2693 			vq->last_avail_idx;
2694 	if (free_entries == 0)
2695 		return 0;
2696 
2697 	rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
2698 
2699 	VHOST_LOG_DATA(DEBUG, "(%s) %s\n", dev->ifname, __func__);
2700 
2701 	count = RTE_MIN(count, MAX_PKT_BURST);
2702 	count = RTE_MIN(count, free_entries);
2703 	VHOST_LOG_DATA(DEBUG, "(%s) about to dequeue %u buffers\n",
2704 			dev->ifname, count);
2705 
2706 	if (rte_pktmbuf_alloc_bulk(mbuf_pool, pkts, count))
2707 		return 0;
2708 
2709 	for (i = 0; i < count; i++) {
2710 		struct buf_vector buf_vec[BUF_VECTOR_MAX];
2711 		uint16_t head_idx;
2712 		uint32_t buf_len;
2713 		uint16_t nr_vec = 0;
2714 		int err;
2715 
2716 		if (unlikely(fill_vec_buf_split(dev, vq,
2717 						vq->last_avail_idx + i,
2718 						&nr_vec, buf_vec,
2719 						&head_idx, &buf_len,
2720 						VHOST_ACCESS_RO) < 0))
2721 			break;
2722 
2723 		update_shadow_used_ring_split(vq, head_idx, 0);
2724 
2725 		err = virtio_dev_pktmbuf_prep(dev, pkts[i], buf_len);
2726 		if (unlikely(err)) {
2727 			/*
2728 			 * mbuf allocation fails for jumbo packets when external
2729 			 * buffer allocation is not allowed and linear buffer
2730 			 * is required. Drop this packet.
2731 			 */
2732 			if (!allocerr_warned) {
2733 				VHOST_LOG_DATA(ERR, "(%s) failed mbuf alloc of size %d from %s.\n",
2734 					dev->ifname, buf_len, mbuf_pool->name);
2735 				allocerr_warned = true;
2736 			}
2737 			dropped += 1;
2738 			i++;
2739 			break;
2740 		}
2741 
2742 		err = copy_desc_to_mbuf(dev, vq, buf_vec, nr_vec, pkts[i],
2743 				mbuf_pool, legacy_ol_flags);
2744 		if (unlikely(err)) {
2745 			if (!allocerr_warned) {
2746 				VHOST_LOG_DATA(ERR, "(%s) failed to copy desc to mbuf.\n",
2747 					dev->ifname);
2748 				allocerr_warned = true;
2749 			}
2750 			dropped += 1;
2751 			i++;
2752 			break;
2753 		}
2754 	}
2755 
2756 	if (dropped)
2757 		rte_pktmbuf_free_bulk(&pkts[i - 1], count - i + 1);
2758 
2759 	vq->last_avail_idx += i;
2760 
2761 	do_data_copy_dequeue(vq);
2762 	if (unlikely(i < count))
2763 		vq->shadow_used_idx = i;
2764 	if (likely(vq->shadow_used_idx)) {
2765 		flush_shadow_used_ring_split(dev, vq);
2766 		vhost_vring_call_split(dev, vq);
2767 	}
2768 
2769 	return (i - dropped);
2770 }
2771 
2772 __rte_noinline
2773 static uint16_t
2774 virtio_dev_tx_split_legacy(struct virtio_net *dev,
2775 	struct vhost_virtqueue *vq, struct rte_mempool *mbuf_pool,
2776 	struct rte_mbuf **pkts, uint16_t count)
2777 {
2778 	return virtio_dev_tx_split(dev, vq, mbuf_pool, pkts, count, true);
2779 }
2780 
2781 __rte_noinline
2782 static uint16_t
2783 virtio_dev_tx_split_compliant(struct virtio_net *dev,
2784 	struct vhost_virtqueue *vq, struct rte_mempool *mbuf_pool,
2785 	struct rte_mbuf **pkts, uint16_t count)
2786 {
2787 	return virtio_dev_tx_split(dev, vq, mbuf_pool, pkts, count, false);
2788 }
2789 
2790 static __rte_always_inline int
2791 vhost_reserve_avail_batch_packed(struct virtio_net *dev,
2792 				 struct vhost_virtqueue *vq,
2793 				 struct rte_mbuf **pkts,
2794 				 uint16_t avail_idx,
2795 				 uintptr_t *desc_addrs,
2796 				 uint16_t *ids)
2797 {
2798 	bool wrap = vq->avail_wrap_counter;
2799 	struct vring_packed_desc *descs = vq->desc_packed;
2800 	uint64_t lens[PACKED_BATCH_SIZE];
2801 	uint64_t buf_lens[PACKED_BATCH_SIZE];
2802 	uint32_t buf_offset = sizeof(struct virtio_net_hdr_mrg_rxbuf);
2803 	uint16_t flags, i;
2804 
2805 	if (unlikely(avail_idx & PACKED_BATCH_MASK))
2806 		return -1;
2807 	if (unlikely((avail_idx + PACKED_BATCH_SIZE) > vq->size))
2808 		return -1;
2809 
2810 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
2811 		flags = descs[avail_idx + i].flags;
2812 		if (unlikely((wrap != !!(flags & VRING_DESC_F_AVAIL)) ||
2813 			     (wrap == !!(flags & VRING_DESC_F_USED))  ||
2814 			     (flags & PACKED_DESC_SINGLE_DEQUEUE_FLAG)))
2815 			return -1;
2816 	}
2817 
2818 	rte_atomic_thread_fence(__ATOMIC_ACQUIRE);
2819 
2820 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
2821 		lens[i] = descs[avail_idx + i].len;
2822 
2823 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
2824 		desc_addrs[i] = vhost_iova_to_vva(dev, vq,
2825 						  descs[avail_idx + i].addr,
2826 						  &lens[i], VHOST_ACCESS_RW);
2827 	}
2828 
2829 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
2830 		if (unlikely(!desc_addrs[i]))
2831 			return -1;
2832 		if (unlikely((lens[i] != descs[avail_idx + i].len)))
2833 			return -1;
2834 	}
2835 
2836 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
2837 		if (virtio_dev_pktmbuf_prep(dev, pkts[i], lens[i]))
2838 			goto err;
2839 	}
2840 
2841 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
2842 		buf_lens[i] = pkts[i]->buf_len - pkts[i]->data_off;
2843 
2844 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
2845 		if (unlikely(buf_lens[i] < (lens[i] - buf_offset)))
2846 			goto err;
2847 	}
2848 
2849 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
2850 		pkts[i]->pkt_len = lens[i] - buf_offset;
2851 		pkts[i]->data_len = pkts[i]->pkt_len;
2852 		ids[i] = descs[avail_idx + i].id;
2853 	}
2854 
2855 	return 0;
2856 
2857 err:
2858 	return -1;
2859 }
2860 
2861 static __rte_always_inline int
2862 virtio_dev_tx_batch_packed(struct virtio_net *dev,
2863 			   struct vhost_virtqueue *vq,
2864 			   struct rte_mbuf **pkts,
2865 			   bool legacy_ol_flags)
2866 {
2867 	uint16_t avail_idx = vq->last_avail_idx;
2868 	uint32_t buf_offset = sizeof(struct virtio_net_hdr_mrg_rxbuf);
2869 	struct virtio_net_hdr *hdr;
2870 	uintptr_t desc_addrs[PACKED_BATCH_SIZE];
2871 	uint16_t ids[PACKED_BATCH_SIZE];
2872 	uint16_t i;
2873 
2874 	if (vhost_reserve_avail_batch_packed(dev, vq, pkts, avail_idx,
2875 					     desc_addrs, ids))
2876 		return -1;
2877 
2878 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
2879 		rte_prefetch0((void *)(uintptr_t)desc_addrs[i]);
2880 
2881 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
2882 		rte_memcpy(rte_pktmbuf_mtod_offset(pkts[i], void *, 0),
2883 			   (void *)(uintptr_t)(desc_addrs[i] + buf_offset),
2884 			   pkts[i]->pkt_len);
2885 
2886 	if (virtio_net_with_host_offload(dev)) {
2887 		vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
2888 			hdr = (struct virtio_net_hdr *)(desc_addrs[i]);
2889 			vhost_dequeue_offload(dev, hdr, pkts[i], legacy_ol_flags);
2890 		}
2891 	}
2892 
2893 	if (virtio_net_is_inorder(dev))
2894 		vhost_shadow_dequeue_batch_packed_inorder(vq,
2895 			ids[PACKED_BATCH_SIZE - 1]);
2896 	else
2897 		vhost_shadow_dequeue_batch_packed(dev, vq, ids);
2898 
2899 	vq_inc_last_avail_packed(vq, PACKED_BATCH_SIZE);
2900 
2901 	return 0;
2902 }
2903 
2904 static __rte_always_inline int
2905 vhost_dequeue_single_packed(struct virtio_net *dev,
2906 			    struct vhost_virtqueue *vq,
2907 			    struct rte_mempool *mbuf_pool,
2908 			    struct rte_mbuf *pkts,
2909 			    uint16_t *buf_id,
2910 			    uint16_t *desc_count,
2911 			    bool legacy_ol_flags)
2912 {
2913 	struct buf_vector buf_vec[BUF_VECTOR_MAX];
2914 	uint32_t buf_len;
2915 	uint16_t nr_vec = 0;
2916 	int err;
2917 	static bool allocerr_warned;
2918 
2919 	if (unlikely(fill_vec_buf_packed(dev, vq,
2920 					 vq->last_avail_idx, desc_count,
2921 					 buf_vec, &nr_vec,
2922 					 buf_id, &buf_len,
2923 					 VHOST_ACCESS_RO) < 0))
2924 		return -1;
2925 
2926 	if (unlikely(virtio_dev_pktmbuf_prep(dev, pkts, buf_len))) {
2927 		if (!allocerr_warned) {
2928 			VHOST_LOG_DATA(ERR, "(%s) failed mbuf alloc of size %d from %s.\n",
2929 				dev->ifname, buf_len, mbuf_pool->name);
2930 			allocerr_warned = true;
2931 		}
2932 		return -1;
2933 	}
2934 
2935 	err = copy_desc_to_mbuf(dev, vq, buf_vec, nr_vec, pkts,
2936 				mbuf_pool, legacy_ol_flags);
2937 	if (unlikely(err)) {
2938 		if (!allocerr_warned) {
2939 			VHOST_LOG_DATA(ERR, "(%s) failed to copy desc to mbuf.\n",
2940 				dev->ifname);
2941 			allocerr_warned = true;
2942 		}
2943 		return -1;
2944 	}
2945 
2946 	return 0;
2947 }
2948 
2949 static __rte_always_inline int
2950 virtio_dev_tx_single_packed(struct virtio_net *dev,
2951 			    struct vhost_virtqueue *vq,
2952 			    struct rte_mempool *mbuf_pool,
2953 			    struct rte_mbuf *pkts,
2954 			    bool legacy_ol_flags)
2955 {
2956 
2957 	uint16_t buf_id, desc_count = 0;
2958 	int ret;
2959 
2960 	ret = vhost_dequeue_single_packed(dev, vq, mbuf_pool, pkts, &buf_id,
2961 					&desc_count, legacy_ol_flags);
2962 
2963 	if (likely(desc_count > 0)) {
2964 		if (virtio_net_is_inorder(dev))
2965 			vhost_shadow_dequeue_single_packed_inorder(vq, buf_id,
2966 								   desc_count);
2967 		else
2968 			vhost_shadow_dequeue_single_packed(vq, buf_id,
2969 					desc_count);
2970 
2971 		vq_inc_last_avail_packed(vq, desc_count);
2972 	}
2973 
2974 	return ret;
2975 }
2976 
2977 __rte_always_inline
2978 static uint16_t
2979 virtio_dev_tx_packed(struct virtio_net *dev,
2980 		     struct vhost_virtqueue *__rte_restrict vq,
2981 		     struct rte_mempool *mbuf_pool,
2982 		     struct rte_mbuf **__rte_restrict pkts,
2983 		     uint32_t count,
2984 		     bool legacy_ol_flags)
2985 {
2986 	uint32_t pkt_idx = 0;
2987 
2988 	if (rte_pktmbuf_alloc_bulk(mbuf_pool, pkts, count))
2989 		return 0;
2990 
2991 	do {
2992 		rte_prefetch0(&vq->desc_packed[vq->last_avail_idx]);
2993 
2994 		if (count - pkt_idx >= PACKED_BATCH_SIZE) {
2995 			if (!virtio_dev_tx_batch_packed(dev, vq,
2996 							&pkts[pkt_idx],
2997 							legacy_ol_flags)) {
2998 				pkt_idx += PACKED_BATCH_SIZE;
2999 				continue;
3000 			}
3001 		}
3002 
3003 		if (virtio_dev_tx_single_packed(dev, vq, mbuf_pool,
3004 						pkts[pkt_idx],
3005 						legacy_ol_flags))
3006 			break;
3007 		pkt_idx++;
3008 	} while (pkt_idx < count);
3009 
3010 	if (pkt_idx != count)
3011 		rte_pktmbuf_free_bulk(&pkts[pkt_idx], count - pkt_idx);
3012 
3013 	if (vq->shadow_used_idx) {
3014 		do_data_copy_dequeue(vq);
3015 
3016 		vhost_flush_dequeue_shadow_packed(dev, vq);
3017 		vhost_vring_call_packed(dev, vq);
3018 	}
3019 
3020 	return pkt_idx;
3021 }
3022 
3023 __rte_noinline
3024 static uint16_t
3025 virtio_dev_tx_packed_legacy(struct virtio_net *dev,
3026 	struct vhost_virtqueue *__rte_restrict vq, struct rte_mempool *mbuf_pool,
3027 	struct rte_mbuf **__rte_restrict pkts, uint32_t count)
3028 {
3029 	return virtio_dev_tx_packed(dev, vq, mbuf_pool, pkts, count, true);
3030 }
3031 
3032 __rte_noinline
3033 static uint16_t
3034 virtio_dev_tx_packed_compliant(struct virtio_net *dev,
3035 	struct vhost_virtqueue *__rte_restrict vq, struct rte_mempool *mbuf_pool,
3036 	struct rte_mbuf **__rte_restrict pkts, uint32_t count)
3037 {
3038 	return virtio_dev_tx_packed(dev, vq, mbuf_pool, pkts, count, false);
3039 }
3040 
3041 uint16_t
3042 rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
3043 	struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
3044 {
3045 	struct virtio_net *dev;
3046 	struct rte_mbuf *rarp_mbuf = NULL;
3047 	struct vhost_virtqueue *vq;
3048 	int16_t success = 1;
3049 
3050 	dev = get_device(vid);
3051 	if (!dev)
3052 		return 0;
3053 
3054 	if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
3055 		VHOST_LOG_DATA(ERR, "(%s) %s: built-in vhost net backend is disabled.\n",
3056 				dev->ifname, __func__);
3057 		return 0;
3058 	}
3059 
3060 	if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->nr_vring))) {
3061 		VHOST_LOG_DATA(ERR, "(%s) %s: invalid virtqueue idx %d.\n",
3062 				dev->ifname, __func__, queue_id);
3063 		return 0;
3064 	}
3065 
3066 	vq = dev->virtqueue[queue_id];
3067 
3068 	if (unlikely(rte_spinlock_trylock(&vq->access_lock) == 0))
3069 		return 0;
3070 
3071 	if (unlikely(!vq->enabled)) {
3072 		count = 0;
3073 		goto out_access_unlock;
3074 	}
3075 
3076 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
3077 		vhost_user_iotlb_rd_lock(vq);
3078 
3079 	if (unlikely(!vq->access_ok))
3080 		if (unlikely(vring_translate(dev, vq) < 0)) {
3081 			count = 0;
3082 			goto out;
3083 		}
3084 
3085 	/*
3086 	 * Construct a RARP broadcast packet, and inject it to the "pkts"
3087 	 * array, to looks like that guest actually send such packet.
3088 	 *
3089 	 * Check user_send_rarp() for more information.
3090 	 *
3091 	 * broadcast_rarp shares a cacheline in the virtio_net structure
3092 	 * with some fields that are accessed during enqueue and
3093 	 * __atomic_compare_exchange_n causes a write if performed compare
3094 	 * and exchange. This could result in false sharing between enqueue
3095 	 * and dequeue.
3096 	 *
3097 	 * Prevent unnecessary false sharing by reading broadcast_rarp first
3098 	 * and only performing compare and exchange if the read indicates it
3099 	 * is likely to be set.
3100 	 */
3101 	if (unlikely(__atomic_load_n(&dev->broadcast_rarp, __ATOMIC_ACQUIRE) &&
3102 			__atomic_compare_exchange_n(&dev->broadcast_rarp,
3103 			&success, 0, 0, __ATOMIC_RELEASE, __ATOMIC_RELAXED))) {
3104 
3105 		rarp_mbuf = rte_net_make_rarp_packet(mbuf_pool, &dev->mac);
3106 		if (rarp_mbuf == NULL) {
3107 			VHOST_LOG_DATA(ERR, "(%s) failed to make RARP packet.\n", dev->ifname);
3108 			count = 0;
3109 			goto out;
3110 		}
3111 		/*
3112 		 * Inject it to the head of "pkts" array, so that switch's mac
3113 		 * learning table will get updated first.
3114 		 */
3115 		pkts[0] = rarp_mbuf;
3116 		pkts++;
3117 		count -= 1;
3118 	}
3119 
3120 	if (vq_is_packed(dev)) {
3121 		if (dev->flags & VIRTIO_DEV_LEGACY_OL_FLAGS)
3122 			count = virtio_dev_tx_packed_legacy(dev, vq, mbuf_pool, pkts, count);
3123 		else
3124 			count = virtio_dev_tx_packed_compliant(dev, vq, mbuf_pool, pkts, count);
3125 	} else {
3126 		if (dev->flags & VIRTIO_DEV_LEGACY_OL_FLAGS)
3127 			count = virtio_dev_tx_split_legacy(dev, vq, mbuf_pool, pkts, count);
3128 		else
3129 			count = virtio_dev_tx_split_compliant(dev, vq, mbuf_pool, pkts, count);
3130 	}
3131 
3132 out:
3133 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
3134 		vhost_user_iotlb_rd_unlock(vq);
3135 
3136 out_access_unlock:
3137 	rte_spinlock_unlock(&vq->access_lock);
3138 
3139 	if (unlikely(rarp_mbuf != NULL))
3140 		count += 1;
3141 
3142 	return count;
3143 }
3144