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