xref: /dpdk/drivers/net/virtio/virtio_rxtx.c (revision d6b324c00fc933f757e68c54c0e50c92826d83f0)
1 /*-
2  *   BSD LICENSE
3  *
4  *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
5  *   All rights reserved.
6  *
7  *   Redistribution and use in source and binary forms, with or without
8  *   modification, are permitted provided that the following conditions
9  *   are met:
10  *
11  *     * Redistributions of source code must retain the above copyright
12  *       notice, this list of conditions and the following disclaimer.
13  *     * Redistributions in binary form must reproduce the above copyright
14  *       notice, this list of conditions and the following disclaimer in
15  *       the documentation and/or other materials provided with the
16  *       distribution.
17  *     * Neither the name of Intel Corporation nor the names of its
18  *       contributors may be used to endorse or promote products derived
19  *       from this software without specific prior written permission.
20  *
21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #include <stdint.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <errno.h>
39 
40 #include <rte_cycles.h>
41 #include <rte_memory.h>
42 #include <rte_memzone.h>
43 #include <rte_branch_prediction.h>
44 #include <rte_mempool.h>
45 #include <rte_malloc.h>
46 #include <rte_mbuf.h>
47 #include <rte_ether.h>
48 #include <rte_ethdev.h>
49 #include <rte_prefetch.h>
50 #include <rte_string_fns.h>
51 #include <rte_errno.h>
52 #include <rte_byteorder.h>
53 
54 #include "virtio_logs.h"
55 #include "virtio_ethdev.h"
56 #include "virtio_pci.h"
57 #include "virtqueue.h"
58 #include "virtio_rxtx.h"
59 
60 #ifdef RTE_LIBRTE_VIRTIO_DEBUG_DUMP
61 #define VIRTIO_DUMP_PACKET(m, len) rte_pktmbuf_dump(stdout, m, len)
62 #else
63 #define  VIRTIO_DUMP_PACKET(m, len) do { } while (0)
64 #endif
65 
66 
67 #define VIRTIO_SIMPLE_FLAGS ((uint32_t)ETH_TXQ_FLAGS_NOMULTSEGS | \
68 	ETH_TXQ_FLAGS_NOOFFLOADS)
69 
70 #ifdef RTE_MACHINE_CPUFLAG_SSSE3
71 static int use_simple_rxtx;
72 #endif
73 
74 static void
75 vq_ring_free_chain(struct virtqueue *vq, uint16_t desc_idx)
76 {
77 	struct vring_desc *dp, *dp_tail;
78 	struct vq_desc_extra *dxp;
79 	uint16_t desc_idx_last = desc_idx;
80 
81 	dp  = &vq->vq_ring.desc[desc_idx];
82 	dxp = &vq->vq_descx[desc_idx];
83 	vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt + dxp->ndescs);
84 	if ((dp->flags & VRING_DESC_F_INDIRECT) == 0) {
85 		while (dp->flags & VRING_DESC_F_NEXT) {
86 			desc_idx_last = dp->next;
87 			dp = &vq->vq_ring.desc[dp->next];
88 		}
89 	}
90 	dxp->ndescs = 0;
91 
92 	/*
93 	 * We must append the existing free chain, if any, to the end of
94 	 * newly freed chain. If the virtqueue was completely used, then
95 	 * head would be VQ_RING_DESC_CHAIN_END (ASSERTed above).
96 	 */
97 	if (vq->vq_desc_tail_idx == VQ_RING_DESC_CHAIN_END) {
98 		vq->vq_desc_head_idx = desc_idx;
99 	} else {
100 		dp_tail = &vq->vq_ring.desc[vq->vq_desc_tail_idx];
101 		dp_tail->next = desc_idx;
102 	}
103 
104 	vq->vq_desc_tail_idx = desc_idx_last;
105 	dp->next = VQ_RING_DESC_CHAIN_END;
106 }
107 
108 static uint16_t
109 virtqueue_dequeue_burst_rx(struct virtqueue *vq, struct rte_mbuf **rx_pkts,
110 			   uint32_t *len, uint16_t num)
111 {
112 	struct vring_used_elem *uep;
113 	struct rte_mbuf *cookie;
114 	uint16_t used_idx, desc_idx;
115 	uint16_t i;
116 
117 	/*  Caller does the check */
118 	for (i = 0; i < num ; i++) {
119 		used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
120 		uep = &vq->vq_ring.used->ring[used_idx];
121 		desc_idx = (uint16_t) uep->id;
122 		len[i] = uep->len;
123 		cookie = (struct rte_mbuf *)vq->vq_descx[desc_idx].cookie;
124 
125 		if (unlikely(cookie == NULL)) {
126 			PMD_DRV_LOG(ERR, "vring descriptor with no mbuf cookie at %u\n",
127 				vq->vq_used_cons_idx);
128 			break;
129 		}
130 
131 		rte_prefetch0(cookie);
132 		rte_packet_prefetch(rte_pktmbuf_mtod(cookie, void *));
133 		rx_pkts[i]  = cookie;
134 		vq->vq_used_cons_idx++;
135 		vq_ring_free_chain(vq, desc_idx);
136 		vq->vq_descx[desc_idx].cookie = NULL;
137 	}
138 
139 	return i;
140 }
141 
142 #ifndef DEFAULT_TX_FREE_THRESH
143 #define DEFAULT_TX_FREE_THRESH 32
144 #endif
145 
146 /* Cleanup from completed transmits. */
147 static void
148 virtio_xmit_cleanup(struct virtqueue *vq, uint16_t num)
149 {
150 	uint16_t i, used_idx, desc_idx;
151 	for (i = 0; i < num; i++) {
152 		struct vring_used_elem *uep;
153 		struct vq_desc_extra *dxp;
154 
155 		used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
156 		uep = &vq->vq_ring.used->ring[used_idx];
157 
158 		desc_idx = (uint16_t) uep->id;
159 		dxp = &vq->vq_descx[desc_idx];
160 		vq->vq_used_cons_idx++;
161 		vq_ring_free_chain(vq, desc_idx);
162 
163 		if (dxp->cookie != NULL) {
164 			rte_pktmbuf_free(dxp->cookie);
165 			dxp->cookie = NULL;
166 		}
167 	}
168 }
169 
170 
171 static inline int
172 virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
173 {
174 	struct vq_desc_extra *dxp;
175 	struct virtio_hw *hw = vq->hw;
176 	struct vring_desc *start_dp;
177 	uint16_t needed = 1;
178 	uint16_t head_idx, idx;
179 
180 	if (unlikely(vq->vq_free_cnt == 0))
181 		return -ENOSPC;
182 	if (unlikely(vq->vq_free_cnt < needed))
183 		return -EMSGSIZE;
184 
185 	head_idx = vq->vq_desc_head_idx;
186 	if (unlikely(head_idx >= vq->vq_nentries))
187 		return -EFAULT;
188 
189 	idx = head_idx;
190 	dxp = &vq->vq_descx[idx];
191 	dxp->cookie = (void *)cookie;
192 	dxp->ndescs = needed;
193 
194 	start_dp = vq->vq_ring.desc;
195 	start_dp[idx].addr =
196 		(uint64_t)(cookie->buf_physaddr + RTE_PKTMBUF_HEADROOM
197 		- hw->vtnet_hdr_size);
198 	start_dp[idx].len =
199 		cookie->buf_len - RTE_PKTMBUF_HEADROOM + hw->vtnet_hdr_size;
200 	start_dp[idx].flags =  VRING_DESC_F_WRITE;
201 	idx = start_dp[idx].next;
202 	vq->vq_desc_head_idx = idx;
203 	if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
204 		vq->vq_desc_tail_idx = idx;
205 	vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - needed);
206 	vq_update_avail_ring(vq, head_idx);
207 
208 	return 0;
209 }
210 
211 static int
212 virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie)
213 {
214 	struct vq_desc_extra *dxp;
215 	struct vring_desc *start_dp;
216 	uint16_t seg_num = cookie->nb_segs;
217 	uint16_t needed = 1 + seg_num;
218 	uint16_t head_idx, idx;
219 	size_t head_size = txvq->hw->vtnet_hdr_size;
220 
221 	if (unlikely(txvq->vq_free_cnt == 0))
222 		return -ENOSPC;
223 	if (unlikely(txvq->vq_free_cnt < needed))
224 		return -EMSGSIZE;
225 	head_idx = txvq->vq_desc_head_idx;
226 	if (unlikely(head_idx >= txvq->vq_nentries))
227 		return -EFAULT;
228 
229 	idx = head_idx;
230 	dxp = &txvq->vq_descx[idx];
231 	dxp->cookie = (void *)cookie;
232 	dxp->ndescs = needed;
233 
234 	start_dp = txvq->vq_ring.desc;
235 	start_dp[idx].addr =
236 		txvq->virtio_net_hdr_mem + idx * head_size;
237 	start_dp[idx].len = head_size;
238 	start_dp[idx].flags = VRING_DESC_F_NEXT;
239 
240 	for (; ((seg_num > 0) && (cookie != NULL)); seg_num--) {
241 		idx = start_dp[idx].next;
242 		start_dp[idx].addr  = rte_mbuf_data_dma_addr(cookie);
243 		start_dp[idx].len   = cookie->data_len;
244 		start_dp[idx].flags = VRING_DESC_F_NEXT;
245 		cookie = cookie->next;
246 	}
247 
248 	start_dp[idx].flags &= ~VRING_DESC_F_NEXT;
249 	idx = start_dp[idx].next;
250 	txvq->vq_desc_head_idx = idx;
251 	if (txvq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
252 		txvq->vq_desc_tail_idx = idx;
253 	txvq->vq_free_cnt = (uint16_t)(txvq->vq_free_cnt - needed);
254 	vq_update_avail_ring(txvq, head_idx);
255 
256 	return 0;
257 }
258 
259 static inline struct rte_mbuf *
260 rte_rxmbuf_alloc(struct rte_mempool *mp)
261 {
262 	struct rte_mbuf *m;
263 
264 	m = __rte_mbuf_raw_alloc(mp);
265 	__rte_mbuf_sanity_check_raw(m, 0);
266 
267 	return m;
268 }
269 
270 static void
271 virtio_dev_vring_start(struct virtqueue *vq, int queue_type)
272 {
273 	struct rte_mbuf *m;
274 	int i, nbufs, error, size = vq->vq_nentries;
275 	struct vring *vr = &vq->vq_ring;
276 	uint8_t *ring_mem = vq->vq_ring_virt_mem;
277 
278 	PMD_INIT_FUNC_TRACE();
279 
280 	/*
281 	 * Reinitialise since virtio port might have been stopped and restarted
282 	 */
283 	memset(vq->vq_ring_virt_mem, 0, vq->vq_ring_size);
284 	vring_init(vr, size, ring_mem, VIRTIO_PCI_VRING_ALIGN);
285 	vq->vq_used_cons_idx = 0;
286 	vq->vq_desc_head_idx = 0;
287 	vq->vq_avail_idx = 0;
288 	vq->vq_desc_tail_idx = (uint16_t)(vq->vq_nentries - 1);
289 	vq->vq_free_cnt = vq->vq_nentries;
290 	memset(vq->vq_descx, 0, sizeof(struct vq_desc_extra) * vq->vq_nentries);
291 
292 	/* Chain all the descriptors in the ring with an END */
293 	for (i = 0; i < size - 1; i++)
294 		vr->desc[i].next = (uint16_t)(i + 1);
295 	vr->desc[i].next = VQ_RING_DESC_CHAIN_END;
296 
297 	/*
298 	 * Disable device(host) interrupting guest
299 	 */
300 	virtqueue_disable_intr(vq);
301 
302 	/* Only rx virtqueue needs mbufs to be allocated at initialization */
303 	if (queue_type == VTNET_RQ) {
304 		if (vq->mpool == NULL)
305 			rte_exit(EXIT_FAILURE,
306 			"Cannot allocate initial mbufs for rx virtqueue");
307 
308 		/* Allocate blank mbufs for the each rx descriptor */
309 		nbufs = 0;
310 		error = ENOSPC;
311 
312 #ifdef RTE_MACHINE_CPUFLAG_SSSE3
313 		if (use_simple_rxtx)
314 			for (i = 0; i < vq->vq_nentries; i++) {
315 				vq->vq_ring.avail->ring[i] = i;
316 				vq->vq_ring.desc[i].flags = VRING_DESC_F_WRITE;
317 			}
318 #endif
319 		memset(&vq->fake_mbuf, 0, sizeof(vq->fake_mbuf));
320 		for (i = 0; i < RTE_PMD_VIRTIO_RX_MAX_BURST; i++)
321 			vq->sw_ring[vq->vq_nentries + i] = &vq->fake_mbuf;
322 
323 		while (!virtqueue_full(vq)) {
324 			m = rte_rxmbuf_alloc(vq->mpool);
325 			if (m == NULL)
326 				break;
327 
328 			/******************************************
329 			*         Enqueue allocated buffers        *
330 			*******************************************/
331 #ifdef RTE_MACHINE_CPUFLAG_SSSE3
332 			if (use_simple_rxtx)
333 				error = virtqueue_enqueue_recv_refill_simple(vq, m);
334 			else
335 #endif
336 				error = virtqueue_enqueue_recv_refill(vq, m);
337 			if (error) {
338 				rte_pktmbuf_free(m);
339 				break;
340 			}
341 			nbufs++;
342 		}
343 
344 		vq_update_avail_idx(vq);
345 
346 		PMD_INIT_LOG(DEBUG, "Allocated %d bufs", nbufs);
347 	} else if (queue_type == VTNET_TQ) {
348 #ifdef RTE_MACHINE_CPUFLAG_SSSE3
349 		if (use_simple_rxtx) {
350 			int mid_idx  = vq->vq_nentries >> 1;
351 			for (i = 0; i < mid_idx; i++) {
352 				vq->vq_ring.avail->ring[i] = i + mid_idx;
353 				vq->vq_ring.desc[i + mid_idx].next = i;
354 				vq->vq_ring.desc[i + mid_idx].addr =
355 					vq->virtio_net_hdr_mem +
356 						mid_idx * vq->hw->vtnet_hdr_size;
357 				vq->vq_ring.desc[i + mid_idx].len =
358 					vq->hw->vtnet_hdr_size;
359 				vq->vq_ring.desc[i + mid_idx].flags =
360 					VRING_DESC_F_NEXT;
361 				vq->vq_ring.desc[i].flags = 0;
362 			}
363 			for (i = mid_idx; i < vq->vq_nentries; i++)
364 				vq->vq_ring.avail->ring[i] = i;
365 		}
366 #endif
367 	}
368 }
369 
370 void
371 virtio_dev_cq_start(struct rte_eth_dev *dev)
372 {
373 	struct virtio_hw *hw = dev->data->dev_private;
374 
375 	if (hw->cvq) {
376 		virtio_dev_vring_start(hw->cvq, VTNET_CQ);
377 		VIRTQUEUE_DUMP((struct virtqueue *)hw->cvq);
378 	}
379 }
380 
381 void
382 virtio_dev_rxtx_start(struct rte_eth_dev *dev)
383 {
384 	/*
385 	 * Start receive and transmit vrings
386 	 * -	Setup vring structure for all queues
387 	 * -	Initialize descriptor for the rx vring
388 	 * -	Allocate blank mbufs for the each rx descriptor
389 	 *
390 	 */
391 	int i;
392 
393 	PMD_INIT_FUNC_TRACE();
394 
395 	/* Start rx vring. */
396 	for (i = 0; i < dev->data->nb_rx_queues; i++) {
397 		virtio_dev_vring_start(dev->data->rx_queues[i], VTNET_RQ);
398 		VIRTQUEUE_DUMP((struct virtqueue *)dev->data->rx_queues[i]);
399 	}
400 
401 	/* Start tx vring. */
402 	for (i = 0; i < dev->data->nb_tx_queues; i++) {
403 		virtio_dev_vring_start(dev->data->tx_queues[i], VTNET_TQ);
404 		VIRTQUEUE_DUMP((struct virtqueue *)dev->data->tx_queues[i]);
405 	}
406 }
407 
408 int
409 virtio_dev_rx_queue_setup(struct rte_eth_dev *dev,
410 			uint16_t queue_idx,
411 			uint16_t nb_desc,
412 			unsigned int socket_id,
413 			__rte_unused const struct rte_eth_rxconf *rx_conf,
414 			struct rte_mempool *mp)
415 {
416 	uint16_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_RQ_QUEUE_IDX;
417 	struct virtqueue *vq;
418 	int ret;
419 
420 	PMD_INIT_FUNC_TRACE();
421 	ret = virtio_dev_queue_setup(dev, VTNET_RQ, queue_idx, vtpci_queue_idx,
422 			nb_desc, socket_id, &vq);
423 	if (ret < 0) {
424 		PMD_INIT_LOG(ERR, "rvq initialization failed");
425 		return ret;
426 	}
427 
428 	/* Create mempool for rx mbuf allocation */
429 	vq->mpool = mp;
430 
431 	dev->data->rx_queues[queue_idx] = vq;
432 
433 #ifdef RTE_MACHINE_CPUFLAG_SSSE3
434 	virtio_rxq_vec_setup(vq);
435 #endif
436 
437 	return 0;
438 }
439 
440 void
441 virtio_dev_rx_queue_release(void *rxq)
442 {
443 	virtio_dev_queue_release(rxq);
444 }
445 
446 /*
447  * struct rte_eth_dev *dev: Used to update dev
448  * uint16_t nb_desc: Defaults to values read from config space
449  * unsigned int socket_id: Used to allocate memzone
450  * const struct rte_eth_txconf *tx_conf: Used to setup tx engine
451  * uint16_t queue_idx: Just used as an index in dev txq list
452  */
453 int
454 virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
455 			uint16_t queue_idx,
456 			uint16_t nb_desc,
457 			unsigned int socket_id,
458 			const struct rte_eth_txconf *tx_conf)
459 {
460 	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
461 
462 #ifdef RTE_MACHINE_CPUFLAG_SSSE3
463 	struct virtio_hw *hw = dev->data->dev_private;
464 #endif
465 	struct virtqueue *vq;
466 	uint16_t tx_free_thresh;
467 	int ret;
468 
469 	PMD_INIT_FUNC_TRACE();
470 
471 	if ((tx_conf->txq_flags & ETH_TXQ_FLAGS_NOXSUMS)
472 	    != ETH_TXQ_FLAGS_NOXSUMS) {
473 		PMD_INIT_LOG(ERR, "TX checksum offload not supported\n");
474 		return -EINVAL;
475 	}
476 
477 #ifdef RTE_MACHINE_CPUFLAG_SSSE3
478 	/* Use simple rx/tx func if single segment and no offloads */
479 	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
480 	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
481 		PMD_INIT_LOG(INFO, "Using simple rx/tx path");
482 		dev->tx_pkt_burst = virtio_xmit_pkts_simple;
483 		dev->rx_pkt_burst = virtio_recv_pkts_vec;
484 		use_simple_rxtx = 1;
485 	}
486 #endif
487 
488 	ret = virtio_dev_queue_setup(dev, VTNET_TQ, queue_idx, vtpci_queue_idx,
489 			nb_desc, socket_id, &vq);
490 	if (ret < 0) {
491 		PMD_INIT_LOG(ERR, "rvq initialization failed");
492 		return ret;
493 	}
494 
495 	tx_free_thresh = tx_conf->tx_free_thresh;
496 	if (tx_free_thresh == 0)
497 		tx_free_thresh =
498 			RTE_MIN(vq->vq_nentries / 4, DEFAULT_TX_FREE_THRESH);
499 
500 	if (tx_free_thresh >= (vq->vq_nentries - 3)) {
501 		RTE_LOG(ERR, PMD, "tx_free_thresh must be less than the "
502 			"number of TX entries minus 3 (%u)."
503 			" (tx_free_thresh=%u port=%u queue=%u)\n",
504 			vq->vq_nentries - 3,
505 			tx_free_thresh, dev->data->port_id, queue_idx);
506 		return -EINVAL;
507 	}
508 
509 	vq->vq_free_thresh = tx_free_thresh;
510 
511 	dev->data->tx_queues[queue_idx] = vq;
512 	return 0;
513 }
514 
515 void
516 virtio_dev_tx_queue_release(void *txq)
517 {
518 	virtio_dev_queue_release(txq);
519 }
520 
521 static void
522 virtio_discard_rxbuf(struct virtqueue *vq, struct rte_mbuf *m)
523 {
524 	int error;
525 	/*
526 	 * Requeue the discarded mbuf. This should always be
527 	 * successful since it was just dequeued.
528 	 */
529 	error = virtqueue_enqueue_recv_refill(vq, m);
530 	if (unlikely(error)) {
531 		RTE_LOG(ERR, PMD, "cannot requeue discarded mbuf");
532 		rte_pktmbuf_free(m);
533 	}
534 }
535 
536 static void
537 virtio_update_packet_stats(struct virtqueue *vq, struct rte_mbuf *mbuf)
538 {
539 	uint32_t s = mbuf->pkt_len;
540 	struct ether_addr *ea;
541 
542 	if (s == 64) {
543 		vq->size_bins[1]++;
544 	} else if (s > 64 && s < 1024) {
545 		uint32_t bin;
546 
547 		/* count zeros, and offset into correct bin */
548 		bin = (sizeof(s) * 8) - __builtin_clz(s) - 5;
549 		vq->size_bins[bin]++;
550 	} else {
551 		if (s < 64)
552 			vq->size_bins[0]++;
553 		else if (s < 1519)
554 			vq->size_bins[6]++;
555 		else if (s >= 1519)
556 			vq->size_bins[7]++;
557 	}
558 
559 	ea = rte_pktmbuf_mtod(mbuf, struct ether_addr *);
560 	vq->multicast += is_multicast_ether_addr(ea);
561 	vq->broadcast += is_broadcast_ether_addr(ea);
562 }
563 
564 #define VIRTIO_MBUF_BURST_SZ 64
565 #define DESC_PER_CACHELINE (RTE_CACHE_LINE_SIZE / sizeof(struct vring_desc))
566 uint16_t
567 virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
568 {
569 	struct virtqueue *rxvq = rx_queue;
570 	struct virtio_hw *hw;
571 	struct rte_mbuf *rxm, *new_mbuf;
572 	uint16_t nb_used, num, nb_rx;
573 	uint32_t len[VIRTIO_MBUF_BURST_SZ];
574 	struct rte_mbuf *rcv_pkts[VIRTIO_MBUF_BURST_SZ];
575 	int error;
576 	uint32_t i, nb_enqueued;
577 	uint32_t hdr_size;
578 
579 	nb_used = VIRTQUEUE_NUSED(rxvq);
580 
581 	virtio_rmb();
582 
583 	num = (uint16_t)(likely(nb_used <= nb_pkts) ? nb_used : nb_pkts);
584 	num = (uint16_t)(likely(num <= VIRTIO_MBUF_BURST_SZ) ? num : VIRTIO_MBUF_BURST_SZ);
585 	if (likely(num > DESC_PER_CACHELINE))
586 		num = num - ((rxvq->vq_used_cons_idx + num) % DESC_PER_CACHELINE);
587 
588 	if (num == 0)
589 		return 0;
590 
591 	num = virtqueue_dequeue_burst_rx(rxvq, rcv_pkts, len, num);
592 	PMD_RX_LOG(DEBUG, "used:%d dequeue:%d", nb_used, num);
593 
594 	hw = rxvq->hw;
595 	nb_rx = 0;
596 	nb_enqueued = 0;
597 	hdr_size = hw->vtnet_hdr_size;
598 
599 	for (i = 0; i < num ; i++) {
600 		rxm = rcv_pkts[i];
601 
602 		PMD_RX_LOG(DEBUG, "packet len:%d", len[i]);
603 
604 		if (unlikely(len[i] < hdr_size + ETHER_HDR_LEN)) {
605 			PMD_RX_LOG(ERR, "Packet drop");
606 			nb_enqueued++;
607 			virtio_discard_rxbuf(rxvq, rxm);
608 			rxvq->errors++;
609 			continue;
610 		}
611 
612 		rxm->port = rxvq->port_id;
613 		rxm->data_off = RTE_PKTMBUF_HEADROOM;
614 		rxm->ol_flags = 0;
615 		rxm->vlan_tci = 0;
616 
617 		rxm->nb_segs = 1;
618 		rxm->next = NULL;
619 		rxm->pkt_len = (uint32_t)(len[i] - hdr_size);
620 		rxm->data_len = (uint16_t)(len[i] - hdr_size);
621 
622 		if (hw->vlan_strip)
623 			rte_vlan_strip(rxm);
624 
625 		VIRTIO_DUMP_PACKET(rxm, rxm->data_len);
626 
627 		rx_pkts[nb_rx++] = rxm;
628 
629 		rxvq->bytes += rx_pkts[nb_rx - 1]->pkt_len;
630 		virtio_update_packet_stats(rxvq, rxm);
631 	}
632 
633 	rxvq->packets += nb_rx;
634 
635 	/* Allocate new mbuf for the used descriptor */
636 	error = ENOSPC;
637 	while (likely(!virtqueue_full(rxvq))) {
638 		new_mbuf = rte_rxmbuf_alloc(rxvq->mpool);
639 		if (unlikely(new_mbuf == NULL)) {
640 			struct rte_eth_dev *dev
641 				= &rte_eth_devices[rxvq->port_id];
642 			dev->data->rx_mbuf_alloc_failed++;
643 			break;
644 		}
645 		error = virtqueue_enqueue_recv_refill(rxvq, new_mbuf);
646 		if (unlikely(error)) {
647 			rte_pktmbuf_free(new_mbuf);
648 			break;
649 		}
650 		nb_enqueued++;
651 	}
652 
653 	if (likely(nb_enqueued)) {
654 		vq_update_avail_idx(rxvq);
655 
656 		if (unlikely(virtqueue_kick_prepare(rxvq))) {
657 			virtqueue_notify(rxvq);
658 			PMD_RX_LOG(DEBUG, "Notified\n");
659 		}
660 	}
661 
662 	return nb_rx;
663 }
664 
665 uint16_t
666 virtio_recv_mergeable_pkts(void *rx_queue,
667 			struct rte_mbuf **rx_pkts,
668 			uint16_t nb_pkts)
669 {
670 	struct virtqueue *rxvq = rx_queue;
671 	struct virtio_hw *hw;
672 	struct rte_mbuf *rxm, *new_mbuf;
673 	uint16_t nb_used, num, nb_rx;
674 	uint32_t len[VIRTIO_MBUF_BURST_SZ];
675 	struct rte_mbuf *rcv_pkts[VIRTIO_MBUF_BURST_SZ];
676 	struct rte_mbuf *prev;
677 	int error;
678 	uint32_t i, nb_enqueued;
679 	uint32_t seg_num;
680 	uint16_t extra_idx;
681 	uint32_t seg_res;
682 	uint32_t hdr_size;
683 
684 	nb_used = VIRTQUEUE_NUSED(rxvq);
685 
686 	virtio_rmb();
687 
688 	if (nb_used == 0)
689 		return 0;
690 
691 	PMD_RX_LOG(DEBUG, "used:%d\n", nb_used);
692 
693 	hw = rxvq->hw;
694 	nb_rx = 0;
695 	i = 0;
696 	nb_enqueued = 0;
697 	seg_num = 0;
698 	extra_idx = 0;
699 	seg_res = 0;
700 	hdr_size = hw->vtnet_hdr_size;
701 
702 	while (i < nb_used) {
703 		struct virtio_net_hdr_mrg_rxbuf *header;
704 
705 		if (nb_rx == nb_pkts)
706 			break;
707 
708 		num = virtqueue_dequeue_burst_rx(rxvq, rcv_pkts, len, 1);
709 		if (num != 1)
710 			continue;
711 
712 		i++;
713 
714 		PMD_RX_LOG(DEBUG, "dequeue:%d\n", num);
715 		PMD_RX_LOG(DEBUG, "packet len:%d\n", len[0]);
716 
717 		rxm = rcv_pkts[0];
718 
719 		if (unlikely(len[0] < hdr_size + ETHER_HDR_LEN)) {
720 			PMD_RX_LOG(ERR, "Packet drop\n");
721 			nb_enqueued++;
722 			virtio_discard_rxbuf(rxvq, rxm);
723 			rxvq->errors++;
724 			continue;
725 		}
726 
727 		header = (struct virtio_net_hdr_mrg_rxbuf *)((char *)rxm->buf_addr +
728 			RTE_PKTMBUF_HEADROOM - hdr_size);
729 		seg_num = header->num_buffers;
730 
731 		if (seg_num == 0)
732 			seg_num = 1;
733 
734 		rxm->data_off = RTE_PKTMBUF_HEADROOM;
735 		rxm->nb_segs = seg_num;
736 		rxm->next = NULL;
737 		rxm->ol_flags = 0;
738 		rxm->vlan_tci = 0;
739 		rxm->pkt_len = (uint32_t)(len[0] - hdr_size);
740 		rxm->data_len = (uint16_t)(len[0] - hdr_size);
741 
742 		rxm->port = rxvq->port_id;
743 		rx_pkts[nb_rx] = rxm;
744 		prev = rxm;
745 
746 		seg_res = seg_num - 1;
747 
748 		while (seg_res != 0) {
749 			/*
750 			 * Get extra segments for current uncompleted packet.
751 			 */
752 			uint16_t  rcv_cnt =
753 				RTE_MIN(seg_res, RTE_DIM(rcv_pkts));
754 			if (likely(VIRTQUEUE_NUSED(rxvq) >= rcv_cnt)) {
755 				uint32_t rx_num =
756 					virtqueue_dequeue_burst_rx(rxvq,
757 					rcv_pkts, len, rcv_cnt);
758 				i += rx_num;
759 				rcv_cnt = rx_num;
760 			} else {
761 				PMD_RX_LOG(ERR,
762 					"No enough segments for packet.\n");
763 				nb_enqueued++;
764 				virtio_discard_rxbuf(rxvq, rxm);
765 				rxvq->errors++;
766 				break;
767 			}
768 
769 			extra_idx = 0;
770 
771 			while (extra_idx < rcv_cnt) {
772 				rxm = rcv_pkts[extra_idx];
773 
774 				rxm->data_off = RTE_PKTMBUF_HEADROOM - hdr_size;
775 				rxm->next = NULL;
776 				rxm->pkt_len = (uint32_t)(len[extra_idx]);
777 				rxm->data_len = (uint16_t)(len[extra_idx]);
778 
779 				if (prev)
780 					prev->next = rxm;
781 
782 				prev = rxm;
783 				rx_pkts[nb_rx]->pkt_len += rxm->pkt_len;
784 				extra_idx++;
785 			};
786 			seg_res -= rcv_cnt;
787 		}
788 
789 		if (hw->vlan_strip)
790 			rte_vlan_strip(rx_pkts[nb_rx]);
791 
792 		VIRTIO_DUMP_PACKET(rx_pkts[nb_rx],
793 			rx_pkts[nb_rx]->data_len);
794 
795 		rxvq->bytes += rx_pkts[nb_rx]->pkt_len;
796 		virtio_update_packet_stats(rxvq, rx_pkts[nb_rx]);
797 		nb_rx++;
798 	}
799 
800 	rxvq->packets += nb_rx;
801 
802 	/* Allocate new mbuf for the used descriptor */
803 	error = ENOSPC;
804 	while (likely(!virtqueue_full(rxvq))) {
805 		new_mbuf = rte_rxmbuf_alloc(rxvq->mpool);
806 		if (unlikely(new_mbuf == NULL)) {
807 			struct rte_eth_dev *dev
808 				= &rte_eth_devices[rxvq->port_id];
809 			dev->data->rx_mbuf_alloc_failed++;
810 			break;
811 		}
812 		error = virtqueue_enqueue_recv_refill(rxvq, new_mbuf);
813 		if (unlikely(error)) {
814 			rte_pktmbuf_free(new_mbuf);
815 			break;
816 		}
817 		nb_enqueued++;
818 	}
819 
820 	if (likely(nb_enqueued)) {
821 		vq_update_avail_idx(rxvq);
822 
823 		if (unlikely(virtqueue_kick_prepare(rxvq))) {
824 			virtqueue_notify(rxvq);
825 			PMD_RX_LOG(DEBUG, "Notified");
826 		}
827 	}
828 
829 	return nb_rx;
830 }
831 
832 uint16_t
833 virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
834 {
835 	struct virtqueue *txvq = tx_queue;
836 	uint16_t nb_used, nb_tx;
837 	int error;
838 
839 	if (unlikely(nb_pkts < 1))
840 		return nb_pkts;
841 
842 	PMD_TX_LOG(DEBUG, "%d packets to xmit", nb_pkts);
843 	nb_used = VIRTQUEUE_NUSED(txvq);
844 
845 	virtio_rmb();
846 	if (likely(nb_used > txvq->vq_nentries - txvq->vq_free_thresh))
847 		virtio_xmit_cleanup(txvq, nb_used);
848 
849 	for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
850 		struct rte_mbuf *txm = tx_pkts[nb_tx];
851 		/* Need one more descriptor for virtio header. */
852 		int need = txm->nb_segs - txvq->vq_free_cnt + 1;
853 
854 		/* Positive value indicates it need free vring descriptors */
855 		if (unlikely(need > 0)) {
856 			nb_used = VIRTQUEUE_NUSED(txvq);
857 			virtio_rmb();
858 			need = RTE_MIN(need, (int)nb_used);
859 
860 			virtio_xmit_cleanup(txvq, need);
861 			need = txm->nb_segs - txvq->vq_free_cnt + 1;
862 			if (unlikely(need > 0)) {
863 				PMD_TX_LOG(ERR,
864 					   "No free tx descriptors to transmit");
865 				break;
866 			}
867 		}
868 
869 		/* Do VLAN tag insertion */
870 		if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
871 			error = rte_vlan_insert(&txm);
872 			if (unlikely(error)) {
873 				rte_pktmbuf_free(txm);
874 				continue;
875 			}
876 		}
877 
878 		/* Enqueue Packet buffers */
879 		error = virtqueue_enqueue_xmit(txvq, txm);
880 		if (unlikely(error)) {
881 			if (error == ENOSPC)
882 				PMD_TX_LOG(ERR, "virtqueue_enqueue Free count = 0");
883 			else if (error == EMSGSIZE)
884 				PMD_TX_LOG(ERR, "virtqueue_enqueue Free count < 1");
885 			else
886 				PMD_TX_LOG(ERR, "virtqueue_enqueue error: %d", error);
887 			break;
888 		}
889 
890 		txvq->bytes += txm->pkt_len;
891 		virtio_update_packet_stats(txvq, txm);
892 	}
893 
894 	txvq->packets += nb_tx;
895 
896 	if (likely(nb_tx)) {
897 		vq_update_avail_idx(txvq);
898 
899 		if (unlikely(virtqueue_kick_prepare(txvq))) {
900 			virtqueue_notify(txvq);
901 			PMD_TX_LOG(DEBUG, "Notified backend after xmit");
902 		}
903 	}
904 
905 	return nb_tx;
906 }
907