-
Notifications
You must be signed in to change notification settings - Fork 16
/
Copy pathvirtio_net.c
1779 lines (1453 loc) · 43.7 KB
/
virtio_net.c
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
/* A network driver using virtio.
*
* Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
//#define DEBUG
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/module.h>
#include <linux/virtio.h>
#include <linux/virtio_net.h>
#include <linux/scatterlist.h>
#include <linux/if_vlan.h>
#include <linux/slab.h>
#include <linux/cpu.h>
static int napi_weight = NAPI_POLL_WEIGHT;
module_param(napi_weight, int, 0444);
static bool csum = true, gso = true;
module_param(csum, bool, 0444);
module_param(gso, bool, 0444);
/* FIXME: MTU in config. */
#define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
#define GOOD_COPY_LEN 128
#define VIRTNET_DRIVER_VERSION "1.0.0"
struct virtnet_stats {
struct u64_stats_sync tx_syncp;
struct u64_stats_sync rx_syncp;
u64 tx_bytes;
u64 tx_packets;
u64 rx_bytes;
u64 rx_packets;
};
/* Internal representation of a send virtqueue */
struct send_queue {
/* Virtqueue associated with this send _queue */
struct virtqueue *vq;
/* TX: fragments + linear part + virtio header */
struct scatterlist sg[MAX_SKB_FRAGS + 2];
/* Name of the send queue: output.$index */
char name[40];
};
/* Internal representation of a receive virtqueue */
struct receive_queue {
/* Virtqueue associated with this receive_queue */
struct virtqueue *vq;
struct napi_struct napi;
/* Number of input buffers, and max we've ever had. */
unsigned int num, max;
/* Chain pages by the private ptr. */
struct page *pages;
/* RX: fragments + linear part + virtio header */
struct scatterlist sg[MAX_SKB_FRAGS + 2];
/* Name of this receive queue: input.$index */
char name[40];
};
struct virtnet_info {
struct virtio_device *vdev;
struct virtqueue *cvq;
struct net_device *dev;
struct send_queue *sq;
struct receive_queue *rq;
unsigned int status;
/* Max # of queue pairs supported by the device */
u16 max_queue_pairs;
/* # of queue pairs currently used by the driver */
u16 curr_queue_pairs;
/* I like... big packets and I cannot lie! */
bool big_packets;
/* Host will merge rx buffers for big packets (shake it! shake it!) */
bool mergeable_rx_bufs;
/* Has control virtqueue */
bool has_cvq;
/* Host can handle any s/g split between our header and packet data */
bool any_header_sg;
/* enable config space updates */
bool config_enable;
/* Active statistics */
struct virtnet_stats __percpu *stats;
/* Work struct for refilling if we run low on memory. */
struct delayed_work refill;
/* Work struct for config space updates */
struct work_struct config_work;
/* Lock for config space updates */
struct mutex config_lock;
/* Does the affinity hint is set for virtqueues? */
bool affinity_hint_set;
/* Per-cpu variable to show the mapping from CPU to virtqueue */
int __percpu *vq_index;
/* CPU hot plug notifier */
struct notifier_block nb;
};
struct skb_vnet_hdr {
union {
struct virtio_net_hdr hdr;
struct virtio_net_hdr_mrg_rxbuf mhdr;
};
};
struct padded_vnet_hdr {
struct virtio_net_hdr hdr;
/*
* virtio_net_hdr should be in a separated sg buffer because of a
* QEMU bug, and data sg buffer shares same page with this header sg.
* This padding makes next sg 16 byte aligned after virtio_net_hdr.
*/
char padding[6];
};
/* Converting between virtqueue no. and kernel tx/rx queue no.
* 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
*/
static int vq2txq(struct virtqueue *vq)
{
return (vq->index - 1) / 2;
}
static int txq2vq(int txq)
{
return txq * 2 + 1;
}
static int vq2rxq(struct virtqueue *vq)
{
return vq->index / 2;
}
static int rxq2vq(int rxq)
{
return rxq * 2;
}
static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
{
return (struct skb_vnet_hdr *)skb->cb;
}
/*
* private is used to chain pages for big packets, put the whole
* most recent used list in the beginning for reuse
*/
static void give_pages(struct receive_queue *rq, struct page *page)
{
struct page *end;
/* Find end of list, sew whole thing into vi->rq.pages. */
for (end = page; end->private; end = (struct page *)end->private);
end->private = (unsigned long)rq->pages;
rq->pages = page;
}
static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
{
struct page *p = rq->pages;
if (p) {
rq->pages = (struct page *)p->private;
/* clear private here, it is used to chain pages */
p->private = 0;
} else
p = alloc_page(gfp_mask);
return p;
}
static void skb_xmit_done(struct virtqueue *vq)
{
struct virtnet_info *vi = vq->vdev->priv;
/* Suppress further interrupts. */
virtqueue_disable_cb(vq);
/* We were probably waiting for more output buffers. */
netif_wake_subqueue(vi->dev, vq2txq(vq));
}
static void set_skb_frag(struct sk_buff *skb, struct page *page,
unsigned int offset, unsigned int *len)
{
int size = min((unsigned)PAGE_SIZE - offset, *len);
int i = skb_shinfo(skb)->nr_frags;
__skb_fill_page_desc(skb, i, page, offset, size);
skb->data_len += size;
skb->len += size;
skb->truesize += PAGE_SIZE;
skb_shinfo(skb)->nr_frags++;
skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
*len -= size;
}
/* Called from bottom half context */
static struct sk_buff *page_to_skb(struct receive_queue *rq,
struct page *page, unsigned int len)
{
struct virtnet_info *vi = rq->vq->vdev->priv;
struct sk_buff *skb;
struct skb_vnet_hdr *hdr;
unsigned int copy, hdr_len, offset;
char *p;
p = page_address(page);
/* copy small packet so we can reuse these pages for small data */
skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
if (unlikely(!skb))
return NULL;
hdr = skb_vnet_hdr(skb);
if (vi->mergeable_rx_bufs) {
hdr_len = sizeof hdr->mhdr;
offset = hdr_len;
} else {
hdr_len = sizeof hdr->hdr;
offset = sizeof(struct padded_vnet_hdr);
}
memcpy(hdr, p, hdr_len);
len -= hdr_len;
p += offset;
copy = len;
if (copy > skb_tailroom(skb))
copy = skb_tailroom(skb);
memcpy(skb_put(skb, copy), p, copy);
len -= copy;
offset += copy;
/*
* Verify that we can indeed put this data into a skb.
* This is here to handle cases when the device erroneously
* tries to receive more than is possible. This is usually
* the case of a broken device.
*/
if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
dev_kfree_skb(skb);
return NULL;
}
while (len) {
set_skb_frag(skb, page, offset, &len);
page = (struct page *)page->private;
offset = 0;
}
if (page)
give_pages(rq, page);
return skb;
}
static int receive_mergeable(struct receive_queue *rq, struct sk_buff *skb)
{
struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
struct page *page;
int num_buf, i, len;
num_buf = hdr->mhdr.num_buffers;
while (--num_buf) {
i = skb_shinfo(skb)->nr_frags;
if (i >= MAX_SKB_FRAGS) {
pr_debug("%s: packet too long\n", skb->dev->name);
skb->dev->stats.rx_length_errors++;
return -EINVAL;
}
page = virtqueue_get_buf(rq->vq, &len);
if (!page) {
pr_debug("%s: rx error: %d buffers missing\n",
skb->dev->name, hdr->mhdr.num_buffers);
skb->dev->stats.rx_length_errors++;
return -EINVAL;
}
if (len > PAGE_SIZE)
len = PAGE_SIZE;
set_skb_frag(skb, page, 0, &len);
--rq->num;
}
return 0;
}
static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
{
struct virtnet_info *vi = rq->vq->vdev->priv;
struct net_device *dev = vi->dev;
struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
struct sk_buff *skb;
struct page *page;
struct skb_vnet_hdr *hdr;
if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
pr_debug("%s: short packet %i\n", dev->name, len);
dev->stats.rx_length_errors++;
if (vi->mergeable_rx_bufs || vi->big_packets)
give_pages(rq, buf);
else
dev_kfree_skb(buf);
return;
}
if (!vi->mergeable_rx_bufs && !vi->big_packets) {
skb = buf;
len -= sizeof(struct virtio_net_hdr);
skb_trim(skb, len);
} else {
page = buf;
skb = page_to_skb(rq, page, len);
if (unlikely(!skb)) {
dev->stats.rx_dropped++;
give_pages(rq, page);
return;
}
if (vi->mergeable_rx_bufs)
if (receive_mergeable(rq, skb)) {
dev_kfree_skb(skb);
return;
}
}
hdr = skb_vnet_hdr(skb);
u64_stats_update_begin(&stats->rx_syncp);
stats->rx_bytes += skb->len;
stats->rx_packets++;
u64_stats_update_end(&stats->rx_syncp);
if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
pr_debug("Needs csum!\n");
if (!skb_partial_csum_set(skb,
hdr->hdr.csum_start,
hdr->hdr.csum_offset))
goto frame_err;
} else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
skb->protocol = eth_type_trans(skb, dev);
pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
ntohs(skb->protocol), skb->len, skb->pkt_type);
if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
pr_debug("GSO!\n");
switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
case VIRTIO_NET_HDR_GSO_TCPV4:
skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
break;
case VIRTIO_NET_HDR_GSO_UDP:
skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
break;
case VIRTIO_NET_HDR_GSO_TCPV6:
skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
break;
default:
net_warn_ratelimited("%s: bad gso type %u.\n",
dev->name, hdr->hdr.gso_type);
goto frame_err;
}
if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
if (skb_shinfo(skb)->gso_size == 0) {
net_warn_ratelimited("%s: zero gso size.\n", dev->name);
goto frame_err;
}
/* Header must be checked, and gso_segs computed. */
skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
skb_shinfo(skb)->gso_segs = 0;
}
netif_receive_skb(skb);
return;
frame_err:
dev->stats.rx_frame_errors++;
dev_kfree_skb(skb);
}
static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp)
{
struct virtnet_info *vi = rq->vq->vdev->priv;
struct sk_buff *skb;
struct skb_vnet_hdr *hdr;
int err;
skb = __netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN, gfp);
if (unlikely(!skb))
return -ENOMEM;
skb_put(skb, MAX_PACKET_LEN);
hdr = skb_vnet_hdr(skb);
sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr);
skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
if (err < 0)
dev_kfree_skb(skb);
return err;
}
static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp)
{
struct page *first, *list = NULL;
char *p;
int i, err, offset;
/* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
first = get_a_page(rq, gfp);
if (!first) {
if (list)
give_pages(rq, list);
return -ENOMEM;
}
sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
/* chain new page in list head to match sg */
first->private = (unsigned long)list;
list = first;
}
first = get_a_page(rq, gfp);
if (!first) {
give_pages(rq, list);
return -ENOMEM;
}
p = page_address(first);
/* rq->sg[0], rq->sg[1] share the same page */
/* a separated rq->sg[0] for virtio_net_hdr only due to QEMU bug */
sg_set_buf(&rq->sg[0], p, sizeof(struct virtio_net_hdr));
/* rq->sg[1] for data packet, from offset */
offset = sizeof(struct padded_vnet_hdr);
sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
/* chain first in list head */
first->private = (unsigned long)list;
err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
first, gfp);
if (err < 0)
give_pages(rq, first);
return err;
}
static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
{
struct page *page;
int err;
page = get_a_page(rq, gfp);
if (!page)
return -ENOMEM;
sg_init_one(rq->sg, page_address(page), PAGE_SIZE);
err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, page, gfp);
if (err < 0)
give_pages(rq, page);
return err;
}
/*
* Returns false if we couldn't fill entirely (OOM).
*
* Normally run in the receive path, but can also be run from ndo_open
* before we're receiving packets, or from refill_work which is
* careful to disable receiving (using napi_disable).
*/
static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp)
{
struct virtnet_info *vi = rq->vq->vdev->priv;
int err;
bool oom;
do {
if (vi->mergeable_rx_bufs)
err = add_recvbuf_mergeable(rq, gfp);
else if (vi->big_packets)
err = add_recvbuf_big(rq, gfp);
else
err = add_recvbuf_small(rq, gfp);
oom = err == -ENOMEM;
if (err)
break;
++rq->num;
} while (rq->vq->num_free);
if (unlikely(rq->num > rq->max))
rq->max = rq->num;
virtqueue_kick(rq->vq);
return !oom;
}
static void skb_recv_done(struct virtqueue *rvq)
{
struct virtnet_info *vi = rvq->vdev->priv;
struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
/* Schedule NAPI, Suppress further interrupts if successful. */
if (napi_schedule_prep(&rq->napi)) {
virtqueue_disable_cb(rvq);
__napi_schedule(&rq->napi);
}
}
static void virtnet_napi_enable(struct receive_queue *rq)
{
napi_enable(&rq->napi);
/* If all buffers were filled by other side before we napi_enabled, we
* won't get another interrupt, so process any outstanding packets
* now. virtnet_poll wants re-enable the queue, so we disable here.
* We synchronize against interrupts via NAPI_STATE_SCHED */
if (napi_schedule_prep(&rq->napi)) {
virtqueue_disable_cb(rq->vq);
local_bh_disable();
__napi_schedule(&rq->napi);
local_bh_enable();
}
}
static void refill_work(struct work_struct *work)
{
struct virtnet_info *vi =
container_of(work, struct virtnet_info, refill.work);
bool still_empty;
int i;
for (i = 0; i < vi->curr_queue_pairs; i++) {
struct receive_queue *rq = &vi->rq[i];
napi_disable(&rq->napi);
still_empty = !try_fill_recv(rq, GFP_KERNEL);
virtnet_napi_enable(rq);
/* In theory, this can happen: if we don't get any buffers in
* we will *never* try to fill again.
*/
if (still_empty)
schedule_delayed_work(&vi->refill, HZ/2);
}
}
static int virtnet_poll(struct napi_struct *napi, int budget)
{
struct receive_queue *rq =
container_of(napi, struct receive_queue, napi);
struct virtnet_info *vi = rq->vq->vdev->priv;
void *buf;
unsigned int r, len, received = 0;
again:
while (received < budget &&
(buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
receive_buf(rq, buf, len);
--rq->num;
received++;
}
if (rq->num < rq->max / 2) {
if (!try_fill_recv(rq, GFP_ATOMIC))
schedule_delayed_work(&vi->refill, 0);
}
/* Out of packets? */
if (received < budget) {
r = virtqueue_enable_cb_prepare(rq->vq);
napi_complete(napi);
if (unlikely(virtqueue_poll(rq->vq, r)) &&
napi_schedule_prep(napi)) {
virtqueue_disable_cb(rq->vq);
__napi_schedule(napi);
goto again;
}
}
return received;
}
static int virtnet_open(struct net_device *dev)
{
struct virtnet_info *vi = netdev_priv(dev);
int i;
for (i = 0; i < vi->max_queue_pairs; i++) {
if (i < vi->curr_queue_pairs)
/* Make sure we have some buffers: if oom use wq. */
if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
schedule_delayed_work(&vi->refill, 0);
virtnet_napi_enable(&vi->rq[i]);
}
return 0;
}
static void free_old_xmit_skbs(struct send_queue *sq)
{
struct sk_buff *skb;
unsigned int len;
struct virtnet_info *vi = sq->vq->vdev->priv;
struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
pr_debug("Sent skb %p\n", skb);
u64_stats_update_begin(&stats->tx_syncp);
stats->tx_bytes += skb->len;
stats->tx_packets++;
u64_stats_update_end(&stats->tx_syncp);
dev_kfree_skb_any(skb);
}
}
static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
{
struct skb_vnet_hdr *hdr;
const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
struct virtnet_info *vi = sq->vq->vdev->priv;
unsigned num_sg;
unsigned hdr_len;
bool can_push;
pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
if (vi->mergeable_rx_bufs)
hdr_len = sizeof hdr->mhdr;
else
hdr_len = sizeof hdr->hdr;
can_push = vi->any_header_sg &&
!((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
!skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
/* Even if we can, don't push here yet as this would skew
* csum_start offset below. */
if (can_push)
hdr = (struct skb_vnet_hdr *)(skb->data - hdr_len);
else
hdr = skb_vnet_hdr(skb);
if (skb->ip_summed == CHECKSUM_PARTIAL) {
hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
hdr->hdr.csum_start = skb_checksum_start_offset(skb);
hdr->hdr.csum_offset = skb->csum_offset;
} else {
hdr->hdr.flags = 0;
hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
}
if (skb_is_gso(skb)) {
hdr->hdr.hdr_len = skb_headlen(skb);
hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
else
BUG();
if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
} else {
hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
}
if (vi->mergeable_rx_bufs)
hdr->mhdr.num_buffers = 0;
if (can_push) {
__skb_push(skb, hdr_len);
num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
/* Pull header back to avoid skew in tx bytes calculations. */
__skb_pull(skb, hdr_len);
} else {
sg_set_buf(sq->sg, hdr, hdr_len);
num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
}
return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
}
static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct virtnet_info *vi = netdev_priv(dev);
int qnum = skb_get_queue_mapping(skb);
struct send_queue *sq = &vi->sq[qnum];
int err;
/* Free up any pending old buffers before queueing new ones. */
free_old_xmit_skbs(sq);
/* Try to transmit */
err = xmit_skb(sq, skb);
/* This should not happen! */
if (unlikely(err)) {
dev->stats.tx_fifo_errors++;
if (net_ratelimit())
dev_warn(&dev->dev,
"Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
dev->stats.tx_dropped++;
kfree_skb(skb);
return NETDEV_TX_OK;
}
virtqueue_kick(sq->vq);
/* Don't wait up for transmitted skbs to be freed. */
skb_orphan(skb);
nf_reset(skb);
/* Apparently nice girls don't return TX_BUSY; stop the queue
* before it gets out of hand. Naturally, this wastes entries. */
if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
netif_stop_subqueue(dev, qnum);
if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
/* More just got used, free them then recheck. */
free_old_xmit_skbs(sq);
if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
netif_start_subqueue(dev, qnum);
virtqueue_disable_cb(sq->vq);
}
}
}
return NETDEV_TX_OK;
}
/*
* Send command via the control virtqueue and check status. Commands
* supported by the hypervisor, as indicated by feature bits, should
* never fail unless improperly formated.
*/
static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
struct scatterlist *out,
struct scatterlist *in)
{
struct scatterlist *sgs[4], hdr, stat;
struct virtio_net_ctrl_hdr ctrl;
virtio_net_ctrl_ack status = ~0;
unsigned out_num = 0, in_num = 0, tmp;
/* Caller should know better */
BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
ctrl.class = class;
ctrl.cmd = cmd;
/* Add header */
sg_init_one(&hdr, &ctrl, sizeof(ctrl));
sgs[out_num++] = &hdr;
if (out)
sgs[out_num++] = out;
if (in)
sgs[out_num + in_num++] = in;
/* Add return status. */
sg_init_one(&stat, &status, sizeof(status));
sgs[out_num + in_num++] = &stat;
BUG_ON(out_num + in_num > ARRAY_SIZE(sgs));
BUG_ON(virtqueue_add_sgs(vi->cvq, sgs, out_num, in_num, vi, GFP_ATOMIC)
< 0);
virtqueue_kick(vi->cvq);
/* Spin for a response, the kick causes an ioport write, trapping
* into the hypervisor, so the request should be handled immediately.
*/
while (!virtqueue_get_buf(vi->cvq, &tmp))
cpu_relax();
return status == VIRTIO_NET_OK;
}
static int virtnet_set_mac_address(struct net_device *dev, void *p)
{
struct virtnet_info *vi = netdev_priv(dev);
struct virtio_device *vdev = vi->vdev;
int ret;
struct sockaddr *addr = p;
struct scatterlist sg;
ret = eth_prepare_mac_addr_change(dev, p);
if (ret)
return ret;
if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
sg_init_one(&sg, addr->sa_data, dev->addr_len);
if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
VIRTIO_NET_CTRL_MAC_ADDR_SET,
&sg, NULL)) {
dev_warn(&vdev->dev,
"Failed to set mac address by vq command.\n");
return -EINVAL;
}
} else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
addr->sa_data, dev->addr_len);
}
eth_commit_mac_addr_change(dev, p);
return 0;
}
static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
struct rtnl_link_stats64 *tot)
{
struct virtnet_info *vi = netdev_priv(dev);
int cpu;
unsigned int start;
for_each_possible_cpu(cpu) {
struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
u64 tpackets, tbytes, rpackets, rbytes;
do {
start = u64_stats_fetch_begin_bh(&stats->tx_syncp);
tpackets = stats->tx_packets;
tbytes = stats->tx_bytes;
} while (u64_stats_fetch_retry_bh(&stats->tx_syncp, start));
do {
start = u64_stats_fetch_begin_bh(&stats->rx_syncp);
rpackets = stats->rx_packets;
rbytes = stats->rx_bytes;
} while (u64_stats_fetch_retry_bh(&stats->rx_syncp, start));
tot->rx_packets += rpackets;
tot->tx_packets += tpackets;
tot->rx_bytes += rbytes;
tot->tx_bytes += tbytes;
}
tot->tx_dropped = dev->stats.tx_dropped;
tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
tot->rx_dropped = dev->stats.rx_dropped;
tot->rx_length_errors = dev->stats.rx_length_errors;
tot->rx_frame_errors = dev->stats.rx_frame_errors;
return tot;
}
#ifdef CONFIG_NET_POLL_CONTROLLER
static void virtnet_netpoll(struct net_device *dev)
{
struct virtnet_info *vi = netdev_priv(dev);
int i;
for (i = 0; i < vi->curr_queue_pairs; i++)
napi_schedule(&vi->rq[i].napi);
}
#endif
static void virtnet_ack_link_announce(struct virtnet_info *vi)
{
rtnl_lock();
if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL, NULL))
dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
rtnl_unlock();
}
static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
{
struct scatterlist sg;
struct virtio_net_ctrl_mq s;
struct net_device *dev = vi->dev;
if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
return 0;
s.virtqueue_pairs = queue_pairs;
sg_init_one(&sg, &s, sizeof(s));
if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg, NULL)) {
dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
queue_pairs);
return -EINVAL;
} else {
vi->curr_queue_pairs = queue_pairs;
schedule_delayed_work(&vi->refill, 0);
}
return 0;
}
static int virtnet_close(struct net_device *dev)
{
struct virtnet_info *vi = netdev_priv(dev);
int i;
/* Make sure refill_work doesn't re-enable napi! */
cancel_delayed_work_sync(&vi->refill);
for (i = 0; i < vi->max_queue_pairs; i++)
napi_disable(&vi->rq[i].napi);
return 0;
}
static void virtnet_set_rx_mode(struct net_device *dev)
{
struct virtnet_info *vi = netdev_priv(dev);
struct scatterlist sg[2];
u8 promisc, allmulti;
struct virtio_net_ctrl_mac *mac_data;
struct netdev_hw_addr *ha;
int uc_count;
int mc_count;
void *buf;
int i;
/* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
return;
promisc = ((dev->flags & IFF_PROMISC) != 0);
allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
sg_init_one(sg, &promisc, sizeof(promisc));
if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
VIRTIO_NET_CTRL_RX_PROMISC,
sg, NULL))
dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
promisc ? "en" : "dis");
sg_init_one(sg, &allmulti, sizeof(allmulti));
if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
VIRTIO_NET_CTRL_RX_ALLMULTI,
sg, NULL))
dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
allmulti ? "en" : "dis");
uc_count = netdev_uc_count(dev);
mc_count = netdev_mc_count(dev);
/* MAC filter - use one buffer for both lists */
buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
(2 * sizeof(mac_data->entries)), GFP_ATOMIC);