summaryrefslogtreecommitdiff
path: root/drivers/net/virtio/virtio_rxtx.c
blob: a8aa87b3258bc0779ab2856ccd5aef295ebb512d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 */

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <rte_cycles.h>
#include <rte_memory.h>
#include <rte_branch_prediction.h>
#include <rte_mempool.h>
#include <rte_malloc.h>
#include <rte_mbuf.h>
#include <rte_ether.h>
#include <rte_ethdev_driver.h>
#include <rte_prefetch.h>
#include <rte_string_fns.h>
#include <rte_errno.h>
#include <rte_byteorder.h>
#include <rte_net.h>
#include <rte_ip.h>
#include <rte_udp.h>
#include <rte_tcp.h>

#include "virtio_logs.h"
#include "virtio_ethdev.h"
#include "virtio_pci.h"
#include "virtqueue.h"
#include "virtio_rxtx.h"
#include "virtio_rxtx_simple.h"

#ifdef RTE_LIBRTE_VIRTIO_DEBUG_DUMP
#define VIRTIO_DUMP_PACKET(m, len) rte_pktmbuf_dump(stdout, m, len)
#else
#define  VIRTIO_DUMP_PACKET(m, len) do { } while (0)
#endif

int
virtio_dev_rx_queue_done(void *rxq, uint16_t offset)
{
	struct virtnet_rx *rxvq = rxq;
	struct virtqueue *vq = rxvq->vq;

	return VIRTQUEUE_NUSED(vq) >= offset;
}

void
vq_ring_free_chain(struct virtqueue *vq, uint16_t desc_idx)
{
	struct vring_desc *dp, *dp_tail;
	struct vq_desc_extra *dxp;
	uint16_t desc_idx_last = desc_idx;

	dp  = &vq->vq_ring.desc[desc_idx];
	dxp = &vq->vq_descx[desc_idx];
	vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt + dxp->ndescs);
	if ((dp->flags & VRING_DESC_F_INDIRECT) == 0) {
		while (dp->flags & VRING_DESC_F_NEXT) {
			desc_idx_last = dp->next;
			dp = &vq->vq_ring.desc[dp->next];
		}
	}
	dxp->ndescs = 0;

	/*
	 * We must append the existing free chain, if any, to the end of
	 * newly freed chain. If the virtqueue was completely used, then
	 * head would be VQ_RING_DESC_CHAIN_END (ASSERTed above).
	 */
	if (vq->vq_desc_tail_idx == VQ_RING_DESC_CHAIN_END) {
		vq->vq_desc_head_idx = desc_idx;
	} else {
		dp_tail = &vq->vq_ring.desc[vq->vq_desc_tail_idx];
		dp_tail->next = desc_idx;
	}

	vq->vq_desc_tail_idx = desc_idx_last;
	dp->next = VQ_RING_DESC_CHAIN_END;
}

static uint16_t
virtqueue_dequeue_burst_rx(struct virtqueue *vq, struct rte_mbuf **rx_pkts,
			   uint32_t *len, uint16_t num)
{
	struct vring_used_elem *uep;
	struct rte_mbuf *cookie;
	uint16_t used_idx, desc_idx;
	uint16_t i;

	/*  Caller does the check */
	for (i = 0; i < num ; i++) {
		used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
		uep = &vq->vq_ring.used->ring[used_idx];
		desc_idx = (uint16_t) uep->id;
		len[i] = uep->len;
		cookie = (struct rte_mbuf *)vq->vq_descx[desc_idx].cookie;

		if (unlikely(cookie == NULL)) {
			PMD_DRV_LOG(ERR, "vring descriptor with no mbuf cookie at %u",
				vq->vq_used_cons_idx);
			break;
		}

		rte_prefetch0(cookie);
		rte_packet_prefetch(rte_pktmbuf_mtod(cookie, void *));
		rx_pkts[i]  = cookie;
		vq->vq_used_cons_idx++;
		vq_ring_free_chain(vq, desc_idx);
		vq->vq_descx[desc_idx].cookie = NULL;
	}

	return i;
}

#ifndef DEFAULT_TX_FREE_THRESH
#define DEFAULT_TX_FREE_THRESH 32
#endif

/* Cleanup from completed transmits. */
static void
virtio_xmit_cleanup(struct virtqueue *vq, uint16_t num)
{
	uint16_t i, used_idx, desc_idx;
	for (i = 0; i < num; i++) {
		struct vring_used_elem *uep;
		struct vq_desc_extra *dxp;

		used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
		uep = &vq->vq_ring.used->ring[used_idx];

		desc_idx = (uint16_t) uep->id;
		dxp = &vq->vq_descx[desc_idx];
		vq->vq_used_cons_idx++;
		vq_ring_free_chain(vq, desc_idx);

		if (dxp->cookie != NULL) {
			rte_pktmbuf_free(dxp->cookie);
			dxp->cookie = NULL;
		}
	}
}


static inline int
virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
{
	struct vq_desc_extra *dxp;
	struct virtio_hw *hw = vq->hw;
	struct vring_desc *start_dp;
	uint16_t needed = 1;
	uint16_t head_idx, idx;

	if (unlikely(vq->vq_free_cnt == 0))
		return -ENOSPC;
	if (unlikely(vq->vq_free_cnt < needed))
		return -EMSGSIZE;

	head_idx = vq->vq_desc_head_idx;
	if (unlikely(head_idx >= vq->vq_nentries))
		return -EFAULT;

	idx = head_idx;
	dxp = &vq->vq_descx[idx];
	dxp->cookie = (void *)cookie;
	dxp->ndescs = needed;

	start_dp = vq->vq_ring.desc;
	start_dp[idx].addr =
		VIRTIO_MBUF_ADDR(cookie, vq) +
		RTE_PKTMBUF_HEADROOM - hw->vtnet_hdr_size;
	start_dp[idx].len =
		cookie->buf_len - RTE_PKTMBUF_HEADROOM + hw->vtnet_hdr_size;
	start_dp[idx].flags =  VRING_DESC_F_WRITE;
	idx = start_dp[idx].next;
	vq->vq_desc_head_idx = idx;
	if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
		vq->vq_desc_tail_idx = idx;
	vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - needed);
	vq_update_avail_ring(vq, head_idx);

	return 0;
}

/* When doing TSO, the IP length is not included in the pseudo header
 * checksum of the packet given to the PMD, but for virtio it is
 * expected.
 */
static void
virtio_tso_fix_cksum(struct rte_mbuf *m)
{
	/* common case: header is not fragmented */
	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
			m->l4_len)) {
		struct ipv4_hdr *iph;
		struct ipv6_hdr *ip6h;
		struct tcp_hdr *th;
		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
		uint32_t tmp;

		iph = rte_pktmbuf_mtod_offset(m, struct ipv4_hdr *, m->l2_len);
		th = RTE_PTR_ADD(iph, m->l3_len);
		if ((iph->version_ihl >> 4) == 4) {
			iph->hdr_checksum = 0;
			iph->hdr_checksum = rte_ipv4_cksum(iph);
			ip_len = iph->total_length;
			ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
				m->l3_len);
		} else {
			ip6h = (struct ipv6_hdr *)iph;
			ip_paylen = ip6h->payload_len;
		}

		/* calculate the new phdr checksum not including ip_paylen */
		prev_cksum = th->cksum;
		tmp = prev_cksum;
		tmp += ip_paylen;
		tmp = (tmp & 0xffff) + (tmp >> 16);
		new_cksum = tmp;

		/* replace it in the packet */
		th->cksum = new_cksum;
	}
}

static inline int
tx_offload_enabled(struct virtio_hw *hw)
{
	return vtpci_with_feature(hw, VIRTIO_NET_F_CSUM) ||
		vtpci_with_feature(hw, VIRTIO_NET_F_HOST_TSO4) ||
		vtpci_with_feature(hw, VIRTIO_NET_F_HOST_TSO6);
}

/* avoid write operation when necessary, to lessen cache issues */
#define ASSIGN_UNLESS_EQUAL(var, val) do {	\
	if ((var) != (val))			\
		(var) = (val);			\
} while (0)

static inline void
virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
		       uint16_t needed, int use_indirect, int can_push)
{
	struct virtio_tx_region *txr = txvq->virtio_net_hdr_mz->addr;
	struct vq_desc_extra *dxp;
	struct virtqueue *vq = txvq->vq;
	struct vring_desc *start_dp;
	uint16_t seg_num = cookie->nb_segs;
	uint16_t head_idx, idx;
	uint16_t head_size = vq->hw->vtnet_hdr_size;
	struct virtio_net_hdr *hdr;
	int offload;

	offload = tx_offload_enabled(vq->hw);
	head_idx = vq->vq_desc_head_idx;
	idx = head_idx;
	dxp = &vq->vq_descx[idx];
	dxp->cookie = (void *)cookie;
	dxp->ndescs = needed;

	start_dp = vq->vq_ring.desc;

	if (can_push) {
		/* prepend cannot fail, checked by caller */
		hdr = (struct virtio_net_hdr *)
			rte_pktmbuf_prepend(cookie, head_size);
		/* rte_pktmbuf_prepend() counts the hdr size to the pkt length,
		 * which is wrong. Below subtract restores correct pkt size.
		 */
		cookie->pkt_len -= head_size;
		/* if offload disabled, it is not zeroed below, do it now */
		if (offload == 0) {
			ASSIGN_UNLESS_EQUAL(hdr->csum_start, 0);
			ASSIGN_UNLESS_EQUAL(hdr->csum_offset, 0);
			ASSIGN_UNLESS_EQUAL(hdr->flags, 0);
			ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
			ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
			ASSIGN_UNLESS_EQUAL(hdr->hdr_len, 0);
		}
	} else if (use_indirect) {
		/* setup tx ring slot to point to indirect
		 * descriptor list stored in reserved region.
		 *
		 * the first slot in indirect ring is already preset
		 * to point to the header in reserved region
		 */
		start_dp[idx].addr  = txvq->virtio_net_hdr_mem +
			RTE_PTR_DIFF(&txr[idx].tx_indir, txr);
		start_dp[idx].len   = (seg_num + 1) * sizeof(struct vring_desc);
		start_dp[idx].flags = VRING_DESC_F_INDIRECT;
		hdr = (struct virtio_net_hdr *)&txr[idx].tx_hdr;

		/* loop below will fill in rest of the indirect elements */
		start_dp = txr[idx].tx_indir;
		idx = 1;
	} else {
		/* setup first tx ring slot to point to header
		 * stored in reserved region.
		 */
		start_dp[idx].addr  = txvq->virtio_net_hdr_mem +
			RTE_PTR_DIFF(&txr[idx].tx_hdr, txr);
		start_dp[idx].len   = vq->hw->vtnet_hdr_size;
		start_dp[idx].flags = VRING_DESC_F_NEXT;
		hdr = (struct virtio_net_hdr *)&txr[idx].tx_hdr;

		idx = start_dp[idx].next;
	}

	/* Checksum Offload / TSO */
	if (offload) {
		if (cookie->ol_flags & PKT_TX_TCP_SEG)
			cookie->ol_flags |= PKT_TX_TCP_CKSUM;

		switch (cookie->ol_flags & PKT_TX_L4_MASK) {
		case PKT_TX_UDP_CKSUM:
			hdr->csum_start = cookie->l2_len + cookie->l3_len;
			hdr->csum_offset = offsetof(struct udp_hdr,
				dgram_cksum);
			hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
			break;

		case PKT_TX_TCP_CKSUM:
			hdr->csum_start = cookie->l2_len + cookie->l3_len;
			hdr->csum_offset = offsetof(struct tcp_hdr, cksum);
			hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
			break;

		default:
			ASSIGN_UNLESS_EQUAL(hdr->csum_start, 0);
			ASSIGN_UNLESS_EQUAL(hdr->csum_offset, 0);
			ASSIGN_UNLESS_EQUAL(hdr->flags, 0);
			break;
		}

		/* TCP Segmentation Offload */
		if (cookie->ol_flags & PKT_TX_TCP_SEG) {
			virtio_tso_fix_cksum(cookie);
			hdr->gso_type = (cookie->ol_flags & PKT_TX_IPV6) ?
				VIRTIO_NET_HDR_GSO_TCPV6 :
				VIRTIO_NET_HDR_GSO_TCPV4;
			hdr->gso_size = cookie->tso_segsz;
			hdr->hdr_len =
				cookie->l2_len +
				cookie->l3_len +
				cookie->l4_len;
		} else {
			ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
			ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
			ASSIGN_UNLESS_EQUAL(hdr->hdr_len, 0);
		}
	}

	do {
		start_dp[idx].addr  = VIRTIO_MBUF_DATA_DMA_ADDR(cookie, vq);
		start_dp[idx].len   = cookie->data_len;
		start_dp[idx].flags = cookie->next ? VRING_DESC_F_NEXT : 0;
		idx = start_dp[idx].next;
	} while ((cookie = cookie->next) != NULL);

	if (use_indirect)
		idx = vq->vq_ring.desc[head_idx].next;

	vq->vq_desc_head_idx = idx;
	if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
		vq->vq_desc_tail_idx = idx;
	vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - needed);
	vq_update_avail_ring(vq, head_idx);
}

void
virtio_dev_cq_start(struct rte_eth_dev *dev)
{
	struct virtio_hw *hw = dev->data->dev_private;

	if (hw->cvq && hw->cvq->vq) {
		rte_spinlock_init(&hw->cvq->lock);
		VIRTQUEUE_DUMP((struct virtqueue *)hw->cvq->vq);
	}
}

int
virtio_dev_rx_queue_setup(struct rte_eth_dev *dev,
			uint16_t queue_idx,
			uint16_t nb_desc,
			unsigned int socket_id __rte_unused,
			const struct rte_eth_rxconf *rx_conf,
			struct rte_mempool *mp)
{
	const struct rte_eth_rxmode *rxmode = &dev->data->dev_conf.rxmode;
	uint16_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_RQ_QUEUE_IDX;
	struct virtio_hw *hw = dev->data->dev_private;
	struct virtqueue *vq = hw->vqs[vtpci_queue_idx];
	struct virtnet_rx *rxvq;

	PMD_INIT_FUNC_TRACE();

	if (nb_desc == 0 || nb_desc > vq->vq_nentries)
		nb_desc = vq->vq_nentries;
	vq->vq_free_cnt = RTE_MIN(vq->vq_free_cnt, nb_desc);

	rxvq = &vq->rxq;
	rxvq->queue_id = queue_idx;
	rxvq->mpool = mp;
	if (rxvq->mpool == NULL) {
		rte_exit(EXIT_FAILURE,
			"Cannot allocate mbufs for rx virtqueue");
	}

	if ((rx_conf->offloads ^ rxmode->offloads) &
	    VIRTIO_PMD_PER_DEVICE_RX_OFFLOADS)
		return -EINVAL;

	dev->data->rx_queues[queue_idx] = rxvq;

	return 0;
}

int
virtio_dev_rx_queue_setup_finish(struct rte_eth_dev *dev, uint16_t queue_idx)
{
	uint16_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_RQ_QUEUE_IDX;
	struct virtio_hw *hw = dev->data->dev_private;
	struct virtqueue *vq = hw->vqs[vtpci_queue_idx];
	struct virtnet_rx *rxvq = &vq->rxq;
	struct rte_mbuf *m;
	uint16_t desc_idx;
	int error, nbufs;

	PMD_INIT_FUNC_TRACE();

	/* Allocate blank mbufs for the each rx descriptor */
	nbufs = 0;

	if (hw->use_simple_rx) {
		for (desc_idx = 0; desc_idx < vq->vq_nentries;
		     desc_idx++) {
			vq->vq_ring.avail->ring[desc_idx] = desc_idx;
			vq->vq_ring.desc[desc_idx].flags =
				VRING_DESC_F_WRITE;
		}

		virtio_rxq_vec_setup(rxvq);
	}

	memset(&rxvq->fake_mbuf, 0, sizeof(rxvq->fake_mbuf));
	for (desc_idx = 0; desc_idx < RTE_PMD_VIRTIO_RX_MAX_BURST;
	     desc_idx++) {
		vq->sw_ring[vq->vq_nentries + desc_idx] =
			&rxvq->fake_mbuf;
	}

	if (hw->use_simple_rx) {
		while (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
			virtio_rxq_rearm_vec(rxvq);
			nbufs += RTE_VIRTIO_VPMD_RX_REARM_THRESH;
		}
	} else {
		while (!virtqueue_full(vq)) {
			m = rte_mbuf_raw_alloc(rxvq->mpool);
			if (m == NULL)
				break;

			/* Enqueue allocated buffers */
			error = virtqueue_enqueue_recv_refill(vq, m);
			if (error) {
				rte_pktmbuf_free(m);
				break;
			}
			nbufs++;
		}

		vq_update_avail_idx(vq);
	}

	PMD_INIT_LOG(DEBUG, "Allocated %d bufs", nbufs);

	VIRTQUEUE_DUMP(vq);

	return 0;
}

/*
 * struct rte_eth_dev *dev: Used to update dev
 * uint16_t nb_desc: Defaults to values read from config space
 * unsigned int socket_id: Used to allocate memzone
 * const struct rte_eth_txconf *tx_conf: Used to setup tx engine
 * uint16_t queue_idx: Just used as an index in dev txq list
 */
int
virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
			uint16_t queue_idx,
			uint16_t nb_desc,
			unsigned int socket_id __rte_unused,
			const struct rte_eth_txconf *tx_conf)
{
	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
	struct virtio_hw *hw = dev->data->dev_private;
	struct virtqueue *vq = hw->vqs[vtpci_queue_idx];
	struct virtnet_tx *txvq;
	uint16_t tx_free_thresh;

	PMD_INIT_FUNC_TRACE();

	/* cannot use simple rxtx funcs with multisegs or offloads */
	if (tx_conf->offloads)
		hw->use_simple_tx = 0;

	if (nb_desc == 0 || nb_desc > vq->vq_nentries)
		nb_desc = vq->vq_nentries;
	vq->vq_free_cnt = RTE_MIN(vq->vq_free_cnt, nb_desc);

	txvq = &vq->txq;
	txvq->queue_id = queue_idx;

	tx_free_thresh = tx_conf->tx_free_thresh;
	if (tx_free_thresh == 0)
		tx_free_thresh =
			RTE_MIN(vq->vq_nentries / 4, DEFAULT_TX_FREE_THRESH);

	if (tx_free_thresh >= (vq->vq_nentries - 3)) {
		RTE_LOG(ERR, PMD, "tx_free_thresh must be less than the "
			"number of TX entries minus 3 (%u)."
			" (tx_free_thresh=%u port=%u queue=%u)\n",
			vq->vq_nentries - 3,
			tx_free_thresh, dev->data->port_id, queue_idx);
		return -EINVAL;
	}

	vq->vq_free_thresh = tx_free_thresh;

	dev->data->tx_queues[queue_idx] = txvq;
	return 0;
}

int
virtio_dev_tx_queue_setup_finish(struct rte_eth_dev *dev,
				uint16_t queue_idx)
{
	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
	struct virtio_hw *hw = dev->data->dev_private;
	struct virtqueue *vq = hw->vqs[vtpci_queue_idx];
	uint16_t mid_idx = vq->vq_nentries >> 1;
	struct virtnet_tx *txvq = &vq->txq;
	uint16_t desc_idx;

	PMD_INIT_FUNC_TRACE();

	if (hw->use_simple_tx) {
		for (desc_idx = 0; desc_idx < mid_idx; desc_idx++) {
			vq->vq_ring.avail->ring[desc_idx] =
				desc_idx + mid_idx;
			vq->vq_ring.desc[desc_idx + mid_idx].next =
				desc_idx;
			vq->vq_ring.desc[desc_idx + mid_idx].addr =
				txvq->virtio_net_hdr_mem +
				offsetof(struct virtio_tx_region, tx_hdr);
			vq->vq_ring.desc[desc_idx + mid_idx].len =
				vq->hw->vtnet_hdr_size;
			vq->vq_ring.desc[desc_idx + mid_idx].flags =
				VRING_DESC_F_NEXT;
			vq->vq_ring.desc[desc_idx].flags = 0;
		}
		for (desc_idx = mid_idx; desc_idx < vq->vq_nentries;
		     desc_idx++)
			vq->vq_ring.avail->ring[desc_idx] = desc_idx;
	}

	VIRTQUEUE_DUMP(vq);

	return 0;
}

static void
virtio_discard_rxbuf(struct virtqueue *vq, struct rte_mbuf *m)
{
	int error;
	/*
	 * Requeue the discarded mbuf. This should always be
	 * successful since it was just dequeued.
	 */
	error = virtqueue_enqueue_recv_refill(vq, m);
	if (unlikely(error)) {
		RTE_LOG(ERR, PMD, "cannot requeue discarded mbuf");
		rte_pktmbuf_free(m);
	}
}

static void
virtio_update_packet_stats(struct virtnet_stats *stats, struct rte_mbuf *mbuf)
{
	uint32_t s = mbuf->pkt_len;
	struct ether_addr *ea;

	if (s == 64) {
		stats->size_bins[1]++;
	} else if (s > 64 && s < 1024) {
		uint32_t bin;

		/* count zeros, and offset into correct bin */
		bin = (sizeof(s) * 8) - __builtin_clz(s) - 5;
		stats->size_bins[bin]++;
	} else {
		if (s < 64)
			stats->size_bins[0]++;
		else if (s < 1519)
			stats->size_bins[6]++;
		else if (s >= 1519)
			stats->size_bins[7]++;
	}

	ea = rte_pktmbuf_mtod(mbuf, struct ether_addr *);
	if (is_multicast_ether_addr(ea)) {
		if (is_broadcast_ether_addr(ea))
			stats->broadcast++;
		else
			stats->multicast++;
	}
}

/* Optionally fill offload information in structure */
static int
virtio_rx_offload(struct rte_mbuf *m, struct virtio_net_hdr *hdr)
{
	struct rte_net_hdr_lens hdr_lens;
	uint32_t hdrlen, ptype;
	int l4_supported = 0;

	/* nothing to do */
	if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
		return 0;

	m->ol_flags |= PKT_RX_IP_CKSUM_UNKNOWN;

	ptype = rte_net_get_ptype(m, &hdr_lens, RTE_PTYPE_ALL_MASK);
	m->packet_type = ptype;
	if ((ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_TCP ||
	    (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_UDP ||
	    (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_SCTP)
		l4_supported = 1;

	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
		hdrlen = hdr_lens.l2_len + hdr_lens.l3_len + hdr_lens.l4_len;
		if (hdr->csum_start <= hdrlen && l4_supported) {
			m->ol_flags |= PKT_RX_L4_CKSUM_NONE;
		} else {
			/* Unknown proto or tunnel, do sw cksum. We can assume
			 * the cksum field is in the first segment since the
			 * buffers we provided to the host are large enough.
			 * In case of SCTP, this will be wrong since it's a CRC
			 * but there's nothing we can do.
			 */
			uint16_t csum = 0, off;

			rte_raw_cksum_mbuf(m, hdr->csum_start,
				rte_pktmbuf_pkt_len(m) - hdr->csum_start,
				&csum);
			if (likely(csum != 0xffff))
				csum = ~csum;
			off = hdr->csum_offset + hdr->csum_start;
			if (rte_pktmbuf_data_len(m) >= off + 1)
				*rte_pktmbuf_mtod_offset(m, uint16_t *,
					off) = csum;
		}
	} else if (hdr->flags & VIRTIO_NET_HDR_F_DATA_VALID && l4_supported) {
		m->ol_flags |= PKT_RX_L4_CKSUM_GOOD;
	}

	/* GSO request, save required information in mbuf */
	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
		/* Check unsupported modes */
		if ((hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) ||
		    (hdr->gso_size == 0)) {
			return -EINVAL;
		}

		/* Update mss lengthes in mbuf */
		m->tso_segsz = hdr->gso_size;
		switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
			case VIRTIO_NET_HDR_GSO_TCPV4:
			case VIRTIO_NET_HDR_GSO_TCPV6:
				m->ol_flags |= PKT_RX_LRO | \
					PKT_RX_L4_CKSUM_NONE;
				break;
			default:
				return -EINVAL;
		}
	}

	return 0;
}

static inline int
rx_offload_enabled(struct virtio_hw *hw)
{
	return vtpci_with_feature(hw, VIRTIO_NET_F_GUEST_CSUM) ||
		vtpci_with_feature(hw, VIRTIO_NET_F_GUEST_TSO4) ||
		vtpci_with_feature(hw, VIRTIO_NET_F_GUEST_TSO6);
}

#define VIRTIO_MBUF_BURST_SZ 64
#define DESC_PER_CACHELINE (RTE_CACHE_LINE_SIZE / sizeof(struct vring_desc))
uint16_t
virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
{
	struct virtnet_rx *rxvq = rx_queue;
	struct virtqueue *vq = rxvq->vq;
	struct virtio_hw *hw = vq->hw;
	struct rte_mbuf *rxm, *new_mbuf;
	uint16_t nb_used, num, nb_rx;
	uint32_t len[VIRTIO_MBUF_BURST_SZ];
	struct rte_mbuf *rcv_pkts[VIRTIO_MBUF_BURST_SZ];
	int error;
	uint32_t i, nb_enqueued;
	uint32_t hdr_size;
	int offload;
	struct virtio_net_hdr *hdr;

	nb_rx = 0;
	if (unlikely(hw->started == 0))
		return nb_rx;

	nb_used = VIRTQUEUE_NUSED(vq);

	virtio_rmb();

	num = likely(nb_used <= nb_pkts) ? nb_used : nb_pkts;
	if (unlikely(num > VIRTIO_MBUF_BURST_SZ))
		num = VIRTIO_MBUF_BURST_SZ;
	if (likely(num > DESC_PER_CACHELINE))
		num = num - ((vq->vq_used_cons_idx + num) % DESC_PER_CACHELINE);

	num = virtqueue_dequeue_burst_rx(vq, rcv_pkts, len, num);
	PMD_RX_LOG(DEBUG, "used:%d dequeue:%d", nb_used, num);

	nb_enqueued = 0;
	hdr_size = hw->vtnet_hdr_size;
	offload = rx_offload_enabled(hw);

	for (i = 0; i < num ; i++) {
		rxm = rcv_pkts[i];

		PMD_RX_LOG(DEBUG, "packet len:%d", len[i]);

		if (unlikely(len[i] < hdr_size + ETHER_HDR_LEN)) {
			PMD_RX_LOG(ERR, "Packet drop");
			nb_enqueued++;
			virtio_discard_rxbuf(vq, rxm);
			rxvq->stats.errors++;
			continue;
		}

		rxm->port = rxvq->port_id;
		rxm->data_off = RTE_PKTMBUF_HEADROOM;
		rxm->ol_flags = 0;
		rxm->vlan_tci = 0;

		rxm->pkt_len = (uint32_t)(len[i] - hdr_size);
		rxm->data_len = (uint16_t)(len[i] - hdr_size);

		hdr = (struct virtio_net_hdr *)((char *)rxm->buf_addr +
			RTE_PKTMBUF_HEADROOM - hdr_size);

		if (hw->vlan_strip)
			rte_vlan_strip(rxm);

		if (offload && virtio_rx_offload(rxm, hdr) < 0) {
			virtio_discard_rxbuf(vq, rxm);
			rxvq->stats.errors++;
			continue;
		}

		VIRTIO_DUMP_PACKET(rxm, rxm->data_len);

		rx_pkts[nb_rx++] = rxm;

		rxvq->stats.bytes += rxm->pkt_len;
		virtio_update_packet_stats(&rxvq->stats, rxm);
	}

	rxvq->stats.packets += nb_rx;

	/* Allocate new mbuf for the used descriptor */
	error = ENOSPC;
	while (likely(!virtqueue_full(vq))) {
		new_mbuf = rte_mbuf_raw_alloc(rxvq->mpool);
		if (unlikely(new_mbuf == NULL)) {
			struct rte_eth_dev *dev
				= &rte_eth_devices[rxvq->port_id];
			dev->data->rx_mbuf_alloc_failed++;
			break;
		}
		error = virtqueue_enqueue_recv_refill(vq, new_mbuf);
		if (unlikely(error)) {
			rte_pktmbuf_free(new_mbuf);
			break;
		}
		nb_enqueued++;
	}

	if (likely(nb_enqueued)) {
		vq_update_avail_idx(vq);

		if (unlikely(virtqueue_kick_prepare(vq))) {
			virtqueue_notify(vq);
			PMD_RX_LOG(DEBUG, "Notified");
		}
	}

	return nb_rx;
}

uint16_t
virtio_recv_mergeable_pkts(void *rx_queue,
			struct rte_mbuf **rx_pkts,
			uint16_t nb_pkts)
{
	struct virtnet_rx *rxvq = rx_queue;
	struct virtqueue *vq = rxvq->vq;
	struct virtio_hw *hw = vq->hw;
	struct rte_mbuf *rxm, *new_mbuf;
	uint16_t nb_used, num, nb_rx;
	uint32_t len[VIRTIO_MBUF_BURST_SZ];
	struct rte_mbuf *rcv_pkts[VIRTIO_MBUF_BURST_SZ];
	struct rte_mbuf *prev;
	int error;
	uint32_t i, nb_enqueued;
	uint32_t seg_num;
	uint16_t extra_idx;
	uint32_t seg_res;
	uint32_t hdr_size;
	int offload;

	nb_rx = 0;
	if (unlikely(hw->started == 0))
		return nb_rx;

	nb_used = VIRTQUEUE_NUSED(vq);

	virtio_rmb();

	PMD_RX_LOG(DEBUG, "used:%d", nb_used);

	i = 0;
	nb_enqueued = 0;
	seg_num = 0;
	extra_idx = 0;
	seg_res = 0;
	hdr_size = hw->vtnet_hdr_size;
	offload = rx_offload_enabled(hw);

	while (i < nb_used) {
		struct virtio_net_hdr_mrg_rxbuf *header;

		if (nb_rx == nb_pkts)
			break;

		num = virtqueue_dequeue_burst_rx(vq, rcv_pkts, len, 1);
		if (num != 1)
			continue;

		i++;

		PMD_RX_LOG(DEBUG, "dequeue:%d", num);
		PMD_RX_LOG(DEBUG, "packet len:%d", len[0]);

		rxm = rcv_pkts[0];

		if (unlikely(len[0] < hdr_size + ETHER_HDR_LEN)) {
			PMD_RX_LOG(ERR, "Packet drop");
			nb_enqueued++;
			virtio_discard_rxbuf(vq, rxm);
			rxvq->stats.errors++;
			continue;
		}

		header = (struct virtio_net_hdr_mrg_rxbuf *)((char *)rxm->buf_addr +
			RTE_PKTMBUF_HEADROOM - hdr_size);
		seg_num = header->num_buffers;

		if (seg_num == 0)
			seg_num = 1;

		rxm->data_off = RTE_PKTMBUF_HEADROOM;
		rxm->nb_segs = seg_num;
		rxm->ol_flags = 0;
		rxm->vlan_tci = 0;
		rxm->pkt_len = (uint32_t)(len[0] - hdr_size);
		rxm->data_len = (uint16_t)(len[0] - hdr_size);

		rxm->port = rxvq->port_id;
		rx_pkts[nb_rx] = rxm;
		prev = rxm;

		if (offload && virtio_rx_offload(rxm, &header->hdr) < 0) {
			virtio_discard_rxbuf(vq, rxm);
			rxvq->stats.errors++;
			continue;
		}

		seg_res = seg_num - 1;

		while (seg_res != 0) {
			/*
			 * Get extra segments for current uncompleted packet.
			 */
			uint16_t  rcv_cnt =
				RTE_MIN(seg_res, RTE_DIM(rcv_pkts));
			if (likely(VIRTQUEUE_NUSED(vq) >= rcv_cnt)) {
				uint32_t rx_num =
					virtqueue_dequeue_burst_rx(vq,
					rcv_pkts, len, rcv_cnt);
				i += rx_num;
				rcv_cnt = rx_num;
			} else {
				PMD_RX_LOG(ERR,
					   "No enough segments for packet.");
				nb_enqueued++;
				virtio_discard_rxbuf(vq, rxm);
				rxvq->stats.errors++;
				break;
			}

			extra_idx = 0;

			while (extra_idx < rcv_cnt) {
				rxm = rcv_pkts[extra_idx];

				rxm->data_off = RTE_PKTMBUF_HEADROOM - hdr_size;
				rxm->pkt_len = (uint32_t)(len[extra_idx]);
				rxm->data_len = (uint16_t)(len[extra_idx]);

				if (prev)
					prev->next = rxm;

				prev = rxm;
				rx_pkts[nb_rx]->pkt_len += rxm->pkt_len;
				extra_idx++;
			};
			seg_res -= rcv_cnt;
		}

		if (hw->vlan_strip)
			rte_vlan_strip(rx_pkts[nb_rx]);

		VIRTIO_DUMP_PACKET(rx_pkts[nb_rx],
			rx_pkts[nb_rx]->data_len);

		rxvq->stats.bytes += rx_pkts[nb_rx]->pkt_len;
		virtio_update_packet_stats(&rxvq->stats, rx_pkts[nb_rx]);
		nb_rx++;
	}

	rxvq->stats.packets += nb_rx;

	/* Allocate new mbuf for the used descriptor */
	error = ENOSPC;
	while (likely(!virtqueue_full(vq))) {
		new_mbuf = rte_mbuf_raw_alloc(rxvq->mpool);
		if (unlikely(new_mbuf == NULL)) {
			struct rte_eth_dev *dev
				= &rte_eth_devices[rxvq->port_id];
			dev->data->rx_mbuf_alloc_failed++;
			break;
		}
		error = virtqueue_enqueue_recv_refill(vq, new_mbuf);
		if (unlikely(error)) {
			rte_pktmbuf_free(new_mbuf);
			break;
		}
		nb_enqueued++;
	}

	if (likely(nb_enqueued)) {
		vq_update_avail_idx(vq);

		if (unlikely(virtqueue_kick_prepare(vq))) {
			virtqueue_notify(vq);
			PMD_RX_LOG(DEBUG, "Notified");
		}
	}

	return nb_rx;
}

uint16_t
virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
{
	struct virtnet_tx *txvq = tx_queue;
	struct virtqueue *vq = txvq->vq;
	struct virtio_hw *hw = vq->hw;
	uint16_t hdr_size = hw->vtnet_hdr_size;
	uint16_t nb_used, nb_tx = 0;
	int error;

	if (unlikely(hw->started == 0 && tx_pkts != hw->inject_pkts))
		return nb_tx;

	if (unlikely(nb_pkts < 1))
		return nb_pkts;

	PMD_TX_LOG(DEBUG, "%d packets to xmit", nb_pkts);
	nb_used = VIRTQUEUE_NUSED(vq);

	virtio_rmb();
	if (likely(nb_used > vq->vq_nentries - vq->vq_free_thresh))
		virtio_xmit_cleanup(vq, nb_used);

	for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
		struct rte_mbuf *txm = tx_pkts[nb_tx];
		int can_push = 0, use_indirect = 0, slots, need;

		/* Do VLAN tag insertion */
		if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
			error = rte_vlan_insert(&txm);
			if (unlikely(error)) {
				rte_pktmbuf_free(txm);
				continue;
			}
		}

		/* optimize ring usage */
		if ((vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) ||
		      vtpci_with_feature(hw, VIRTIO_F_VERSION_1)) &&
		    rte_mbuf_refcnt_read(txm) == 1 &&
		    RTE_MBUF_DIRECT(txm) &&
		    txm->nb_segs == 1 &&
		    rte_pktmbuf_headroom(txm) >= hdr_size &&
		    rte_is_aligned(rte_pktmbuf_mtod(txm, char *),
				   __alignof__(struct virtio_net_hdr_mrg_rxbuf)))
			can_push = 1;
		else if (vtpci_with_feature(hw, VIRTIO_RING_F_INDIRECT_DESC) &&
			 txm->nb_segs < VIRTIO_MAX_TX_INDIRECT)
			use_indirect = 1;

		/* How many main ring entries are needed to this Tx?
		 * any_layout => number of segments
		 * indirect   => 1
		 * default    => number of segments + 1
		 */
		slots = use_indirect ? 1 : (txm->nb_segs + !can_push);
		need = slots - vq->vq_free_cnt;

		/* Positive value indicates it need free vring descriptors */
		if (unlikely(need > 0)) {
			nb_used = VIRTQUEUE_NUSED(vq);
			virtio_rmb();
			need = RTE_MIN(need, (int)nb_used);

			virtio_xmit_cleanup(vq, need);
			need = slots - vq->vq_free_cnt;
			if (unlikely(need > 0)) {
				PMD_TX_LOG(ERR,
					   "No free tx descriptors to transmit");
				break;
			}
		}

		/* Enqueue Packet buffers */
		virtqueue_enqueue_xmit(txvq, txm, slots, use_indirect, can_push);

		txvq->stats.bytes += txm->pkt_len;
		virtio_update_packet_stats(&txvq->stats, txm);
	}

	txvq->stats.packets += nb_tx;

	if (likely(nb_tx)) {
		vq_update_avail_idx(vq);

		if (unlikely(virtqueue_kick_prepare(vq))) {
			virtqueue_notify(vq);
			PMD_TX_LOG(DEBUG, "Notified backend after xmit");
		}
	}

	return nb_tx;
}