virtio_net: use virtqueue_xxx wrappers
[linux-2.6.git] / drivers / net / virtio_net.c
1 /* A network driver using virtio.
2  *
3  * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  */
19 //#define DEBUG
20 #include <linux/netdevice.h>
21 #include <linux/etherdevice.h>
22 #include <linux/ethtool.h>
23 #include <linux/module.h>
24 #include <linux/virtio.h>
25 #include <linux/virtio_net.h>
26 #include <linux/scatterlist.h>
27 #include <linux/if_vlan.h>
28 #include <linux/slab.h>
29
30 static int napi_weight = 128;
31 module_param(napi_weight, int, 0444);
32
33 static int csum = 1, gso = 1;
34 module_param(csum, bool, 0444);
35 module_param(gso, bool, 0444);
36
37 /* FIXME: MTU in config. */
38 #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
39 #define GOOD_COPY_LEN   128
40
41 #define VIRTNET_SEND_COMMAND_SG_MAX    2
42
43 struct virtnet_info
44 {
45         struct virtio_device *vdev;
46         struct virtqueue *rvq, *svq, *cvq;
47         struct net_device *dev;
48         struct napi_struct napi;
49         unsigned int status;
50
51         /* Number of input buffers, and max we've ever had. */
52         unsigned int num, max;
53
54         /* I like... big packets and I cannot lie! */
55         bool big_packets;
56
57         /* Host will merge rx buffers for big packets (shake it! shake it!) */
58         bool mergeable_rx_bufs;
59
60         /* Work struct for refilling if we run low on memory. */
61         struct delayed_work refill;
62
63         /* Chain pages by the private ptr. */
64         struct page *pages;
65 };
66
67 struct skb_vnet_hdr {
68         union {
69                 struct virtio_net_hdr hdr;
70                 struct virtio_net_hdr_mrg_rxbuf mhdr;
71         };
72         unsigned int num_sg;
73 };
74
75 struct padded_vnet_hdr {
76         struct virtio_net_hdr hdr;
77         /*
78          * virtio_net_hdr should be in a separated sg buffer because of a
79          * QEMU bug, and data sg buffer shares same page with this header sg.
80          * This padding makes next sg 16 byte aligned after virtio_net_hdr.
81          */
82         char padding[6];
83 };
84
85 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
86 {
87         return (struct skb_vnet_hdr *)skb->cb;
88 }
89
90 /*
91  * private is used to chain pages for big packets, put the whole
92  * most recent used list in the beginning for reuse
93  */
94 static void give_pages(struct virtnet_info *vi, struct page *page)
95 {
96         struct page *end;
97
98         /* Find end of list, sew whole thing into vi->pages. */
99         for (end = page; end->private; end = (struct page *)end->private);
100         end->private = (unsigned long)vi->pages;
101         vi->pages = page;
102 }
103
104 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
105 {
106         struct page *p = vi->pages;
107
108         if (p) {
109                 vi->pages = (struct page *)p->private;
110                 /* clear private here, it is used to chain pages */
111                 p->private = 0;
112         } else
113                 p = alloc_page(gfp_mask);
114         return p;
115 }
116
117 static void skb_xmit_done(struct virtqueue *svq)
118 {
119         struct virtnet_info *vi = svq->vdev->priv;
120
121         /* Suppress further interrupts. */
122         virtqueue_disable_cb(svq);
123
124         /* We were probably waiting for more output buffers. */
125         netif_wake_queue(vi->dev);
126 }
127
128 static void set_skb_frag(struct sk_buff *skb, struct page *page,
129                          unsigned int offset, unsigned int *len)
130 {
131         int i = skb_shinfo(skb)->nr_frags;
132         skb_frag_t *f;
133
134         f = &skb_shinfo(skb)->frags[i];
135         f->size = min((unsigned)PAGE_SIZE - offset, *len);
136         f->page_offset = offset;
137         f->page = page;
138
139         skb->data_len += f->size;
140         skb->len += f->size;
141         skb_shinfo(skb)->nr_frags++;
142         *len -= f->size;
143 }
144
145 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
146                                    struct page *page, unsigned int len)
147 {
148         struct sk_buff *skb;
149         struct skb_vnet_hdr *hdr;
150         unsigned int copy, hdr_len, offset;
151         char *p;
152
153         p = page_address(page);
154
155         /* copy small packet so we can reuse these pages for small data */
156         skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
157         if (unlikely(!skb))
158                 return NULL;
159
160         hdr = skb_vnet_hdr(skb);
161
162         if (vi->mergeable_rx_bufs) {
163                 hdr_len = sizeof hdr->mhdr;
164                 offset = hdr_len;
165         } else {
166                 hdr_len = sizeof hdr->hdr;
167                 offset = sizeof(struct padded_vnet_hdr);
168         }
169
170         memcpy(hdr, p, hdr_len);
171
172         len -= hdr_len;
173         p += offset;
174
175         copy = len;
176         if (copy > skb_tailroom(skb))
177                 copy = skb_tailroom(skb);
178         memcpy(skb_put(skb, copy), p, copy);
179
180         len -= copy;
181         offset += copy;
182
183         while (len) {
184                 set_skb_frag(skb, page, offset, &len);
185                 page = (struct page *)page->private;
186                 offset = 0;
187         }
188
189         if (page)
190                 give_pages(vi, page);
191
192         return skb;
193 }
194
195 static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
196 {
197         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
198         struct page *page;
199         int num_buf, i, len;
200
201         num_buf = hdr->mhdr.num_buffers;
202         while (--num_buf) {
203                 i = skb_shinfo(skb)->nr_frags;
204                 if (i >= MAX_SKB_FRAGS) {
205                         pr_debug("%s: packet too long\n", skb->dev->name);
206                         skb->dev->stats.rx_length_errors++;
207                         return -EINVAL;
208                 }
209
210                 page = virtqueue_get_buf(vi->rvq, &len);
211                 if (!page) {
212                         pr_debug("%s: rx error: %d buffers missing\n",
213                                  skb->dev->name, hdr->mhdr.num_buffers);
214                         skb->dev->stats.rx_length_errors++;
215                         return -EINVAL;
216                 }
217                 if (len > PAGE_SIZE)
218                         len = PAGE_SIZE;
219
220                 set_skb_frag(skb, page, 0, &len);
221
222                 --vi->num;
223         }
224         return 0;
225 }
226
227 static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
228 {
229         struct virtnet_info *vi = netdev_priv(dev);
230         struct sk_buff *skb;
231         struct page *page;
232         struct skb_vnet_hdr *hdr;
233
234         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
235                 pr_debug("%s: short packet %i\n", dev->name, len);
236                 dev->stats.rx_length_errors++;
237                 if (vi->mergeable_rx_bufs || vi->big_packets)
238                         give_pages(vi, buf);
239                 else
240                         dev_kfree_skb(buf);
241                 return;
242         }
243
244         if (!vi->mergeable_rx_bufs && !vi->big_packets) {
245                 skb = buf;
246                 len -= sizeof(struct virtio_net_hdr);
247                 skb_trim(skb, len);
248         } else {
249                 page = buf;
250                 skb = page_to_skb(vi, page, len);
251                 if (unlikely(!skb)) {
252                         dev->stats.rx_dropped++;
253                         give_pages(vi, page);
254                         return;
255                 }
256                 if (vi->mergeable_rx_bufs)
257                         if (receive_mergeable(vi, skb)) {
258                                 dev_kfree_skb(skb);
259                                 return;
260                         }
261         }
262
263         hdr = skb_vnet_hdr(skb);
264         skb->truesize += skb->data_len;
265         dev->stats.rx_bytes += skb->len;
266         dev->stats.rx_packets++;
267
268         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
269                 pr_debug("Needs csum!\n");
270                 if (!skb_partial_csum_set(skb,
271                                           hdr->hdr.csum_start,
272                                           hdr->hdr.csum_offset))
273                         goto frame_err;
274         }
275
276         skb->protocol = eth_type_trans(skb, dev);
277         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
278                  ntohs(skb->protocol), skb->len, skb->pkt_type);
279
280         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
281                 pr_debug("GSO!\n");
282                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
283                 case VIRTIO_NET_HDR_GSO_TCPV4:
284                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
285                         break;
286                 case VIRTIO_NET_HDR_GSO_UDP:
287                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
288                         break;
289                 case VIRTIO_NET_HDR_GSO_TCPV6:
290                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
291                         break;
292                 default:
293                         if (net_ratelimit())
294                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
295                                        dev->name, hdr->hdr.gso_type);
296                         goto frame_err;
297                 }
298
299                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
300                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
301
302                 skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
303                 if (skb_shinfo(skb)->gso_size == 0) {
304                         if (net_ratelimit())
305                                 printk(KERN_WARNING "%s: zero gso size.\n",
306                                        dev->name);
307                         goto frame_err;
308                 }
309
310                 /* Header must be checked, and gso_segs computed. */
311                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
312                 skb_shinfo(skb)->gso_segs = 0;
313         }
314
315         netif_receive_skb(skb);
316         return;
317
318 frame_err:
319         dev->stats.rx_frame_errors++;
320         dev_kfree_skb(skb);
321 }
322
323 static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
324 {
325         struct sk_buff *skb;
326         struct skb_vnet_hdr *hdr;
327         struct scatterlist sg[2];
328         int err;
329
330         sg_init_table(sg, 2);
331         skb = netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN);
332         if (unlikely(!skb))
333                 return -ENOMEM;
334
335         skb_put(skb, MAX_PACKET_LEN);
336
337         hdr = skb_vnet_hdr(skb);
338         sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr);
339
340         skb_to_sgvec(skb, sg + 1, 0, skb->len);
341
342         err = virtqueue_add_buf(vi->rvq, sg, 0, 2, skb);
343         if (err < 0)
344                 dev_kfree_skb(skb);
345
346         return err;
347 }
348
349 static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
350 {
351         struct scatterlist sg[MAX_SKB_FRAGS + 2];
352         struct page *first, *list = NULL;
353         char *p;
354         int i, err, offset;
355
356         sg_init_table(sg, MAX_SKB_FRAGS + 2);
357         /* page in sg[MAX_SKB_FRAGS + 1] is list tail */
358         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
359                 first = get_a_page(vi, gfp);
360                 if (!first) {
361                         if (list)
362                                 give_pages(vi, list);
363                         return -ENOMEM;
364                 }
365                 sg_set_buf(&sg[i], page_address(first), PAGE_SIZE);
366
367                 /* chain new page in list head to match sg */
368                 first->private = (unsigned long)list;
369                 list = first;
370         }
371
372         first = get_a_page(vi, gfp);
373         if (!first) {
374                 give_pages(vi, list);
375                 return -ENOMEM;
376         }
377         p = page_address(first);
378
379         /* sg[0], sg[1] share the same page */
380         /* a separated sg[0] for  virtio_net_hdr only during to QEMU bug*/
381         sg_set_buf(&sg[0], p, sizeof(struct virtio_net_hdr));
382
383         /* sg[1] for data packet, from offset */
384         offset = sizeof(struct padded_vnet_hdr);
385         sg_set_buf(&sg[1], p + offset, PAGE_SIZE - offset);
386
387         /* chain first in list head */
388         first->private = (unsigned long)list;
389         err = virtqueue_add_buf(vi->rvq, sg, 0, MAX_SKB_FRAGS + 2,
390                                        first);
391         if (err < 0)
392                 give_pages(vi, first);
393
394         return err;
395 }
396
397 static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
398 {
399         struct page *page;
400         struct scatterlist sg;
401         int err;
402
403         page = get_a_page(vi, gfp);
404         if (!page)
405                 return -ENOMEM;
406
407         sg_init_one(&sg, page_address(page), PAGE_SIZE);
408
409         err = virtqueue_add_buf(vi->rvq, &sg, 0, 1, page);
410         if (err < 0)
411                 give_pages(vi, page);
412
413         return err;
414 }
415
416 /* Returns false if we couldn't fill entirely (OOM). */
417 static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
418 {
419         int err;
420         bool oom = false;
421
422         do {
423                 if (vi->mergeable_rx_bufs)
424                         err = add_recvbuf_mergeable(vi, gfp);
425                 else if (vi->big_packets)
426                         err = add_recvbuf_big(vi, gfp);
427                 else
428                         err = add_recvbuf_small(vi, gfp);
429
430                 if (err < 0) {
431                         oom = true;
432                         break;
433                 }
434                 ++vi->num;
435         } while (err > 0);
436         if (unlikely(vi->num > vi->max))
437                 vi->max = vi->num;
438         virtqueue_kick(vi->rvq);
439         return !oom;
440 }
441
442 static void skb_recv_done(struct virtqueue *rvq)
443 {
444         struct virtnet_info *vi = rvq->vdev->priv;
445         /* Schedule NAPI, Suppress further interrupts if successful. */
446         if (napi_schedule_prep(&vi->napi)) {
447                 virtqueue_disable_cb(rvq);
448                 __napi_schedule(&vi->napi);
449         }
450 }
451
452 static void refill_work(struct work_struct *work)
453 {
454         struct virtnet_info *vi;
455         bool still_empty;
456
457         vi = container_of(work, struct virtnet_info, refill.work);
458         napi_disable(&vi->napi);
459         still_empty = !try_fill_recv(vi, GFP_KERNEL);
460         napi_enable(&vi->napi);
461
462         /* In theory, this can happen: if we don't get any buffers in
463          * we will *never* try to fill again. */
464         if (still_empty)
465                 schedule_delayed_work(&vi->refill, HZ/2);
466 }
467
468 static int virtnet_poll(struct napi_struct *napi, int budget)
469 {
470         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
471         void *buf;
472         unsigned int len, received = 0;
473
474 again:
475         while (received < budget &&
476                (buf = virtqueue_get_buf(vi->rvq, &len)) != NULL) {
477                 receive_buf(vi->dev, buf, len);
478                 --vi->num;
479                 received++;
480         }
481
482         if (vi->num < vi->max / 2) {
483                 if (!try_fill_recv(vi, GFP_ATOMIC))
484                         schedule_delayed_work(&vi->refill, 0);
485         }
486
487         /* Out of packets? */
488         if (received < budget) {
489                 napi_complete(napi);
490                 if (unlikely(!virtqueue_enable_cb(vi->rvq)) &&
491                     napi_schedule_prep(napi)) {
492                         virtqueue_disable_cb(vi->rvq);
493                         __napi_schedule(napi);
494                         goto again;
495                 }
496         }
497
498         return received;
499 }
500
501 static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
502 {
503         struct sk_buff *skb;
504         unsigned int len, tot_sgs = 0;
505
506         while ((skb = virtqueue_get_buf(vi->svq, &len)) != NULL) {
507                 pr_debug("Sent skb %p\n", skb);
508                 vi->dev->stats.tx_bytes += skb->len;
509                 vi->dev->stats.tx_packets++;
510                 tot_sgs += skb_vnet_hdr(skb)->num_sg;
511                 dev_kfree_skb_any(skb);
512         }
513         return tot_sgs;
514 }
515
516 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
517 {
518         struct scatterlist sg[2+MAX_SKB_FRAGS];
519         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
520         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
521
522         sg_init_table(sg, 2+MAX_SKB_FRAGS);
523
524         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
525
526         if (skb->ip_summed == CHECKSUM_PARTIAL) {
527                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
528                 hdr->hdr.csum_start = skb->csum_start - skb_headroom(skb);
529                 hdr->hdr.csum_offset = skb->csum_offset;
530         } else {
531                 hdr->hdr.flags = 0;
532                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
533         }
534
535         if (skb_is_gso(skb)) {
536                 hdr->hdr.hdr_len = skb_headlen(skb);
537                 hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
538                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
539                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
540                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
541                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
542                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
543                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
544                 else
545                         BUG();
546                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
547                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
548         } else {
549                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
550                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
551         }
552
553         hdr->mhdr.num_buffers = 0;
554
555         /* Encode metadata header at front. */
556         if (vi->mergeable_rx_bufs)
557                 sg_set_buf(sg, &hdr->mhdr, sizeof hdr->mhdr);
558         else
559                 sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr);
560
561         hdr->num_sg = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
562         return virtqueue_add_buf(vi->svq, sg, hdr->num_sg, 0, skb);
563 }
564
565 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
566 {
567         struct virtnet_info *vi = netdev_priv(dev);
568         int capacity;
569
570 again:
571         /* Free up any pending old buffers before queueing new ones. */
572         free_old_xmit_skbs(vi);
573
574         /* Try to transmit */
575         capacity = xmit_skb(vi, skb);
576
577         /* This can happen with OOM and indirect buffers. */
578         if (unlikely(capacity < 0)) {
579                 netif_stop_queue(dev);
580                 dev_warn(&dev->dev, "Unexpected full queue\n");
581                 if (unlikely(!virtqueue_enable_cb(vi->svq))) {
582                         virtqueue_disable_cb(vi->svq);
583                         netif_start_queue(dev);
584                         goto again;
585                 }
586                 return NETDEV_TX_BUSY;
587         }
588         virtqueue_kick(vi->svq);
589
590         /* Don't wait up for transmitted skbs to be freed. */
591         skb_orphan(skb);
592         nf_reset(skb);
593
594         /* Apparently nice girls don't return TX_BUSY; stop the queue
595          * before it gets out of hand.  Naturally, this wastes entries. */
596         if (capacity < 2+MAX_SKB_FRAGS) {
597                 netif_stop_queue(dev);
598                 if (unlikely(!virtqueue_enable_cb(vi->svq))) {
599                         /* More just got used, free them then recheck. */
600                         capacity += free_old_xmit_skbs(vi);
601                         if (capacity >= 2+MAX_SKB_FRAGS) {
602                                 netif_start_queue(dev);
603                                 virtqueue_disable_cb(vi->svq);
604                         }
605                 }
606         }
607
608         return NETDEV_TX_OK;
609 }
610
611 static int virtnet_set_mac_address(struct net_device *dev, void *p)
612 {
613         struct virtnet_info *vi = netdev_priv(dev);
614         struct virtio_device *vdev = vi->vdev;
615         int ret;
616
617         ret = eth_mac_addr(dev, p);
618         if (ret)
619                 return ret;
620
621         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
622                 vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
623                                   dev->dev_addr, dev->addr_len);
624
625         return 0;
626 }
627
628 #ifdef CONFIG_NET_POLL_CONTROLLER
629 static void virtnet_netpoll(struct net_device *dev)
630 {
631         struct virtnet_info *vi = netdev_priv(dev);
632
633         napi_schedule(&vi->napi);
634 }
635 #endif
636
637 static int virtnet_open(struct net_device *dev)
638 {
639         struct virtnet_info *vi = netdev_priv(dev);
640
641         napi_enable(&vi->napi);
642
643         /* If all buffers were filled by other side before we napi_enabled, we
644          * won't get another interrupt, so process any outstanding packets
645          * now.  virtnet_poll wants re-enable the queue, so we disable here.
646          * We synchronize against interrupts via NAPI_STATE_SCHED */
647         if (napi_schedule_prep(&vi->napi)) {
648                 virtqueue_disable_cb(vi->rvq);
649                 __napi_schedule(&vi->napi);
650         }
651         return 0;
652 }
653
654 /*
655  * Send command via the control virtqueue and check status.  Commands
656  * supported by the hypervisor, as indicated by feature bits, should
657  * never fail unless improperly formated.
658  */
659 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
660                                  struct scatterlist *data, int out, int in)
661 {
662         struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
663         struct virtio_net_ctrl_hdr ctrl;
664         virtio_net_ctrl_ack status = ~0;
665         unsigned int tmp;
666         int i;
667
668         /* Caller should know better */
669         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
670                 (out + in > VIRTNET_SEND_COMMAND_SG_MAX));
671
672         out++; /* Add header */
673         in++; /* Add return status */
674
675         ctrl.class = class;
676         ctrl.cmd = cmd;
677
678         sg_init_table(sg, out + in);
679
680         sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
681         for_each_sg(data, s, out + in - 2, i)
682                 sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
683         sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
684
685         BUG_ON(virtqueue_add_buf(vi->cvq, sg, out, in, vi) < 0);
686
687         virtqueue_kick(vi->cvq);
688
689         /*
690          * Spin for a response, the kick causes an ioport write, trapping
691          * into the hypervisor, so the request should be handled immediately.
692          */
693         while (!virtqueue_get_buf(vi->cvq, &tmp))
694                 cpu_relax();
695
696         return status == VIRTIO_NET_OK;
697 }
698
699 static int virtnet_close(struct net_device *dev)
700 {
701         struct virtnet_info *vi = netdev_priv(dev);
702
703         napi_disable(&vi->napi);
704
705         return 0;
706 }
707
708 static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
709 {
710         struct virtnet_info *vi = netdev_priv(dev);
711         struct virtio_device *vdev = vi->vdev;
712
713         if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM))
714                 return -ENOSYS;
715
716         return ethtool_op_set_tx_hw_csum(dev, data);
717 }
718
719 static void virtnet_set_rx_mode(struct net_device *dev)
720 {
721         struct virtnet_info *vi = netdev_priv(dev);
722         struct scatterlist sg[2];
723         u8 promisc, allmulti;
724         struct virtio_net_ctrl_mac *mac_data;
725         struct dev_addr_list *addr;
726         struct netdev_hw_addr *ha;
727         int uc_count;
728         int mc_count;
729         void *buf;
730         int i;
731
732         /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
733         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
734                 return;
735
736         promisc = ((dev->flags & IFF_PROMISC) != 0);
737         allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
738
739         sg_init_one(sg, &promisc, sizeof(promisc));
740
741         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
742                                   VIRTIO_NET_CTRL_RX_PROMISC,
743                                   sg, 1, 0))
744                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
745                          promisc ? "en" : "dis");
746
747         sg_init_one(sg, &allmulti, sizeof(allmulti));
748
749         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
750                                   VIRTIO_NET_CTRL_RX_ALLMULTI,
751                                   sg, 1, 0))
752                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
753                          allmulti ? "en" : "dis");
754
755         uc_count = netdev_uc_count(dev);
756         mc_count = netdev_mc_count(dev);
757         /* MAC filter - use one buffer for both lists */
758         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
759                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
760         mac_data = buf;
761         if (!buf) {
762                 dev_warn(&dev->dev, "No memory for MAC address buffer\n");
763                 return;
764         }
765
766         sg_init_table(sg, 2);
767
768         /* Store the unicast list and count in the front of the buffer */
769         mac_data->entries = uc_count;
770         i = 0;
771         netdev_for_each_uc_addr(ha, dev)
772                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
773
774         sg_set_buf(&sg[0], mac_data,
775                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
776
777         /* multicast list and count fill the end */
778         mac_data = (void *)&mac_data->macs[uc_count][0];
779
780         mac_data->entries = mc_count;
781         i = 0;
782         netdev_for_each_mc_addr(addr, dev)
783                 memcpy(&mac_data->macs[i++][0], addr->da_addr, ETH_ALEN);
784
785         sg_set_buf(&sg[1], mac_data,
786                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
787
788         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
789                                   VIRTIO_NET_CTRL_MAC_TABLE_SET,
790                                   sg, 2, 0))
791                 dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
792
793         kfree(buf);
794 }
795
796 static void virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
797 {
798         struct virtnet_info *vi = netdev_priv(dev);
799         struct scatterlist sg;
800
801         sg_init_one(&sg, &vid, sizeof(vid));
802
803         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
804                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
805                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
806 }
807
808 static void virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
809 {
810         struct virtnet_info *vi = netdev_priv(dev);
811         struct scatterlist sg;
812
813         sg_init_one(&sg, &vid, sizeof(vid));
814
815         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
816                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
817                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
818 }
819
820 static const struct ethtool_ops virtnet_ethtool_ops = {
821         .set_tx_csum = virtnet_set_tx_csum,
822         .set_sg = ethtool_op_set_sg,
823         .set_tso = ethtool_op_set_tso,
824         .set_ufo = ethtool_op_set_ufo,
825         .get_link = ethtool_op_get_link,
826 };
827
828 #define MIN_MTU 68
829 #define MAX_MTU 65535
830
831 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
832 {
833         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
834                 return -EINVAL;
835         dev->mtu = new_mtu;
836         return 0;
837 }
838
839 static const struct net_device_ops virtnet_netdev = {
840         .ndo_open            = virtnet_open,
841         .ndo_stop            = virtnet_close,
842         .ndo_start_xmit      = start_xmit,
843         .ndo_validate_addr   = eth_validate_addr,
844         .ndo_set_mac_address = virtnet_set_mac_address,
845         .ndo_set_rx_mode     = virtnet_set_rx_mode,
846         .ndo_change_mtu      = virtnet_change_mtu,
847         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
848         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
849 #ifdef CONFIG_NET_POLL_CONTROLLER
850         .ndo_poll_controller = virtnet_netpoll,
851 #endif
852 };
853
854 static void virtnet_update_status(struct virtnet_info *vi)
855 {
856         u16 v;
857
858         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS))
859                 return;
860
861         vi->vdev->config->get(vi->vdev,
862                               offsetof(struct virtio_net_config, status),
863                               &v, sizeof(v));
864
865         /* Ignore unknown (future) status bits */
866         v &= VIRTIO_NET_S_LINK_UP;
867
868         if (vi->status == v)
869                 return;
870
871         vi->status = v;
872
873         if (vi->status & VIRTIO_NET_S_LINK_UP) {
874                 netif_carrier_on(vi->dev);
875                 netif_wake_queue(vi->dev);
876         } else {
877                 netif_carrier_off(vi->dev);
878                 netif_stop_queue(vi->dev);
879         }
880 }
881
882 static void virtnet_config_changed(struct virtio_device *vdev)
883 {
884         struct virtnet_info *vi = vdev->priv;
885
886         virtnet_update_status(vi);
887 }
888
889 static int virtnet_probe(struct virtio_device *vdev)
890 {
891         int err;
892         struct net_device *dev;
893         struct virtnet_info *vi;
894         struct virtqueue *vqs[3];
895         vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
896         const char *names[] = { "input", "output", "control" };
897         int nvqs;
898
899         /* Allocate ourselves a network device with room for our info */
900         dev = alloc_etherdev(sizeof(struct virtnet_info));
901         if (!dev)
902                 return -ENOMEM;
903
904         /* Set up network device as normal. */
905         dev->netdev_ops = &virtnet_netdev;
906         dev->features = NETIF_F_HIGHDMA;
907         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
908         SET_NETDEV_DEV(dev, &vdev->dev);
909
910         /* Do we support "hardware" checksums? */
911         if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
912                 /* This opens up the world of extra features. */
913                 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
914                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
915                         dev->features |= NETIF_F_TSO | NETIF_F_UFO
916                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
917                 }
918                 /* Individual feature bits: what can host handle? */
919                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
920                         dev->features |= NETIF_F_TSO;
921                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
922                         dev->features |= NETIF_F_TSO6;
923                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
924                         dev->features |= NETIF_F_TSO_ECN;
925                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
926                         dev->features |= NETIF_F_UFO;
927         }
928
929         /* Configuration may specify what MAC to use.  Otherwise random. */
930         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
931                 vdev->config->get(vdev,
932                                   offsetof(struct virtio_net_config, mac),
933                                   dev->dev_addr, dev->addr_len);
934         } else
935                 random_ether_addr(dev->dev_addr);
936
937         /* Set up our device-specific information */
938         vi = netdev_priv(dev);
939         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
940         vi->dev = dev;
941         vi->vdev = vdev;
942         vdev->priv = vi;
943         vi->pages = NULL;
944         INIT_DELAYED_WORK(&vi->refill, refill_work);
945
946         /* If we can receive ANY GSO packets, we must allocate large ones. */
947         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
948             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
949             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
950                 vi->big_packets = true;
951
952         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
953                 vi->mergeable_rx_bufs = true;
954
955         /* We expect two virtqueues, receive then send,
956          * and optionally control. */
957         nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
958
959         err = vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names);
960         if (err)
961                 goto free;
962
963         vi->rvq = vqs[0];
964         vi->svq = vqs[1];
965
966         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
967                 vi->cvq = vqs[2];
968
969                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
970                         dev->features |= NETIF_F_HW_VLAN_FILTER;
971         }
972
973         err = register_netdev(dev);
974         if (err) {
975                 pr_debug("virtio_net: registering device failed\n");
976                 goto free_vqs;
977         }
978
979         /* Last of all, set up some receive buffers. */
980         try_fill_recv(vi, GFP_KERNEL);
981
982         /* If we didn't even get one input buffer, we're useless. */
983         if (vi->num == 0) {
984                 err = -ENOMEM;
985                 goto unregister;
986         }
987
988         vi->status = VIRTIO_NET_S_LINK_UP;
989         virtnet_update_status(vi);
990         netif_carrier_on(dev);
991
992         pr_debug("virtnet: registered device %s\n", dev->name);
993         return 0;
994
995 unregister:
996         unregister_netdev(dev);
997         cancel_delayed_work_sync(&vi->refill);
998 free_vqs:
999         vdev->config->del_vqs(vdev);
1000 free:
1001         free_netdev(dev);
1002         return err;
1003 }
1004
1005 static void free_unused_bufs(struct virtnet_info *vi)
1006 {
1007         void *buf;
1008         while (1) {
1009                 buf = virtqueue_detach_unused_buf(vi->svq);
1010                 if (!buf)
1011                         break;
1012                 dev_kfree_skb(buf);
1013         }
1014         while (1) {
1015                 buf = virtqueue_detach_unused_buf(vi->rvq);
1016                 if (!buf)
1017                         break;
1018                 if (vi->mergeable_rx_bufs || vi->big_packets)
1019                         give_pages(vi, buf);
1020                 else
1021                         dev_kfree_skb(buf);
1022                 --vi->num;
1023         }
1024         BUG_ON(vi->num != 0);
1025 }
1026
1027 static void __devexit virtnet_remove(struct virtio_device *vdev)
1028 {
1029         struct virtnet_info *vi = vdev->priv;
1030
1031         /* Stop all the virtqueues. */
1032         vdev->config->reset(vdev);
1033
1034
1035         unregister_netdev(vi->dev);
1036         cancel_delayed_work_sync(&vi->refill);
1037
1038         /* Free unused buffers in both send and recv, if any. */
1039         free_unused_bufs(vi);
1040
1041         vdev->config->del_vqs(vi->vdev);
1042
1043         while (vi->pages)
1044                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
1045
1046         free_netdev(vi->dev);
1047 }
1048
1049 static struct virtio_device_id id_table[] = {
1050         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1051         { 0 },
1052 };
1053
1054 static unsigned int features[] = {
1055         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1056         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1057         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1058         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1059         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1060         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1061         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1062 };
1063
1064 static struct virtio_driver virtio_net_driver = {
1065         .feature_table = features,
1066         .feature_table_size = ARRAY_SIZE(features),
1067         .driver.name =  KBUILD_MODNAME,
1068         .driver.owner = THIS_MODULE,
1069         .id_table =     id_table,
1070         .probe =        virtnet_probe,
1071         .remove =       __devexit_p(virtnet_remove),
1072         .config_changed = virtnet_config_changed,
1073 };
1074
1075 static int __init init(void)
1076 {
1077         return register_virtio_driver(&virtio_net_driver);
1078 }
1079
1080 static void __exit fini(void)
1081 {
1082         unregister_virtio_driver(&virtio_net_driver);
1083 }
1084 module_init(init);
1085 module_exit(fini);
1086
1087 MODULE_DEVICE_TABLE(virtio, id_table);
1088 MODULE_DESCRIPTION("Virtio network driver");
1089 MODULE_LICENSE("GPL");