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