Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
[linux-2.6] / 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/module.h>
23 #include <linux/virtio.h>
24 #include <linux/virtio_net.h>
25 #include <linux/scatterlist.h>
26
27 static int napi_weight = 128;
28 module_param(napi_weight, int, 0444);
29
30 static int csum = 1, gso = 1;
31 module_param(csum, bool, 0444);
32 module_param(gso, bool, 0444);
33
34 /* FIXME: MTU in config. */
35 #define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
36
37 struct virtnet_info
38 {
39         struct virtio_device *vdev;
40         struct virtqueue *rvq, *svq;
41         struct net_device *dev;
42         struct napi_struct napi;
43
44         /* The skb we couldn't send because buffers were full. */
45         struct sk_buff *last_xmit_skb;
46
47         /* Number of input buffers, and max we've ever had. */
48         unsigned int num, max;
49
50         /* Receive & send queues. */
51         struct sk_buff_head recv;
52         struct sk_buff_head send;
53 };
54
55 static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
56 {
57         return (struct virtio_net_hdr *)skb->cb;
58 }
59
60 static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
61 {
62         sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
63 }
64
65 static void skb_xmit_done(struct virtqueue *svq)
66 {
67         struct virtnet_info *vi = svq->vdev->priv;
68
69         /* Suppress further interrupts. */
70         svq->vq_ops->disable_cb(svq);
71         /* We were waiting for more output buffers. */
72         netif_wake_queue(vi->dev);
73 }
74
75 static void receive_skb(struct net_device *dev, struct sk_buff *skb,
76                         unsigned len)
77 {
78         struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
79
80         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
81                 pr_debug("%s: short packet %i\n", dev->name, len);
82                 dev->stats.rx_length_errors++;
83                 goto drop;
84         }
85         len -= sizeof(struct virtio_net_hdr);
86         BUG_ON(len > MAX_PACKET_LEN);
87
88         skb_trim(skb, len);
89         skb->protocol = eth_type_trans(skb, dev);
90         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
91                  ntohs(skb->protocol), skb->len, skb->pkt_type);
92         dev->stats.rx_bytes += skb->len;
93         dev->stats.rx_packets++;
94
95         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
96                 pr_debug("Needs csum!\n");
97                 if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
98                         goto frame_err;
99         }
100
101         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
102                 pr_debug("GSO!\n");
103                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
104                 case VIRTIO_NET_HDR_GSO_TCPV4:
105                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
106                         break;
107                 case VIRTIO_NET_HDR_GSO_UDP:
108                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
109                         break;
110                 case VIRTIO_NET_HDR_GSO_TCPV6:
111                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
112                         break;
113                 default:
114                         if (net_ratelimit())
115                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
116                                        dev->name, hdr->gso_type);
117                         goto frame_err;
118                 }
119
120                 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
121                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
122
123                 skb_shinfo(skb)->gso_size = hdr->gso_size;
124                 if (skb_shinfo(skb)->gso_size == 0) {
125                         if (net_ratelimit())
126                                 printk(KERN_WARNING "%s: zero gso size.\n",
127                                        dev->name);
128                         goto frame_err;
129                 }
130
131                 /* Header must be checked, and gso_segs computed. */
132                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
133                 skb_shinfo(skb)->gso_segs = 0;
134         }
135
136         netif_receive_skb(skb);
137         return;
138
139 frame_err:
140         dev->stats.rx_frame_errors++;
141 drop:
142         dev_kfree_skb(skb);
143 }
144
145 static void try_fill_recv(struct virtnet_info *vi)
146 {
147         struct sk_buff *skb;
148         struct scatterlist sg[2+MAX_SKB_FRAGS];
149         int num, err;
150
151         sg_init_table(sg, 2+MAX_SKB_FRAGS);
152         for (;;) {
153                 skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
154                 if (unlikely(!skb))
155                         break;
156
157                 skb_put(skb, MAX_PACKET_LEN);
158                 vnet_hdr_to_sg(sg, skb);
159                 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
160                 skb_queue_head(&vi->recv, skb);
161
162                 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
163                 if (err) {
164                         skb_unlink(skb, &vi->recv);
165                         kfree_skb(skb);
166                         break;
167                 }
168                 vi->num++;
169         }
170         if (unlikely(vi->num > vi->max))
171                 vi->max = vi->num;
172         vi->rvq->vq_ops->kick(vi->rvq);
173 }
174
175 static void skb_recv_done(struct virtqueue *rvq)
176 {
177         struct virtnet_info *vi = rvq->vdev->priv;
178         /* Schedule NAPI, Suppress further interrupts if successful. */
179         if (netif_rx_schedule_prep(vi->dev, &vi->napi)) {
180                 rvq->vq_ops->disable_cb(rvq);
181                 __netif_rx_schedule(vi->dev, &vi->napi);
182         }
183 }
184
185 static int virtnet_poll(struct napi_struct *napi, int budget)
186 {
187         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
188         struct sk_buff *skb = NULL;
189         unsigned int len, received = 0;
190
191 again:
192         while (received < budget &&
193                (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
194                 __skb_unlink(skb, &vi->recv);
195                 receive_skb(vi->dev, skb, len);
196                 vi->num--;
197                 received++;
198         }
199
200         /* FIXME: If we oom and completely run out of inbufs, we need
201          * to start a timer trying to fill more. */
202         if (vi->num < vi->max / 2)
203                 try_fill_recv(vi);
204
205         /* Out of packets? */
206         if (received < budget) {
207                 netif_rx_complete(vi->dev, napi);
208                 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
209                     && napi_schedule_prep(napi)) {
210                         vi->rvq->vq_ops->disable_cb(vi->rvq);
211                         __netif_rx_schedule(vi->dev, napi);
212                         goto again;
213                 }
214         }
215
216         return received;
217 }
218
219 static void free_old_xmit_skbs(struct virtnet_info *vi)
220 {
221         struct sk_buff *skb;
222         unsigned int len;
223
224         while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
225                 pr_debug("Sent skb %p\n", skb);
226                 __skb_unlink(skb, &vi->send);
227                 vi->dev->stats.tx_bytes += skb->len;
228                 vi->dev->stats.tx_packets++;
229                 kfree_skb(skb);
230         }
231 }
232
233 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
234 {
235         int num;
236         struct scatterlist sg[2+MAX_SKB_FRAGS];
237         struct virtio_net_hdr *hdr;
238         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
239
240         sg_init_table(sg, 2+MAX_SKB_FRAGS);
241
242         pr_debug("%s: xmit %p " MAC_FMT "\n", vi->dev->name, skb,
243                  dest[0], dest[1], dest[2],
244                  dest[3], dest[4], dest[5]);
245
246         /* Encode metadata header at front. */
247         hdr = skb_vnet_hdr(skb);
248         if (skb->ip_summed == CHECKSUM_PARTIAL) {
249                 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
250                 hdr->csum_start = skb->csum_start - skb_headroom(skb);
251                 hdr->csum_offset = skb->csum_offset;
252         } else {
253                 hdr->flags = 0;
254                 hdr->csum_offset = hdr->csum_start = 0;
255         }
256
257         if (skb_is_gso(skb)) {
258                 hdr->hdr_len = skb_transport_header(skb) - skb->data;
259                 hdr->gso_size = skb_shinfo(skb)->gso_size;
260                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
261                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
262                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
263                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
264                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
265                         hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
266                 else
267                         BUG();
268                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
269                         hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
270         } else {
271                 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
272                 hdr->gso_size = hdr->hdr_len = 0;
273         }
274
275         vnet_hdr_to_sg(sg, skb);
276         num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
277
278         return vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
279 }
280
281 static int start_xmit(struct sk_buff *skb, struct net_device *dev)
282 {
283         struct virtnet_info *vi = netdev_priv(dev);
284
285 again:
286         /* Free up any pending old buffers before queueing new ones. */
287         free_old_xmit_skbs(vi);
288
289         /* If we has a buffer left over from last time, send it now. */
290         if (vi->last_xmit_skb) {
291                 if (xmit_skb(vi, vi->last_xmit_skb) != 0) {
292                         /* Drop this skb: we only queue one. */
293                         vi->dev->stats.tx_dropped++;
294                         kfree_skb(skb);
295                         goto stop_queue;
296                 }
297                 vi->last_xmit_skb = NULL;
298         }
299
300         /* Put new one in send queue and do transmit */
301         __skb_queue_head(&vi->send, skb);
302         if (xmit_skb(vi, skb) != 0) {
303                 vi->last_xmit_skb = skb;
304                 goto stop_queue;
305         }
306 done:
307         vi->svq->vq_ops->kick(vi->svq);
308         return NETDEV_TX_OK;
309
310 stop_queue:
311         pr_debug("%s: virtio not prepared to send\n", dev->name);
312         netif_stop_queue(dev);
313
314         /* Activate callback for using skbs: if this returns false it
315          * means some were used in the meantime. */
316         if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
317                 vi->svq->vq_ops->disable_cb(vi->svq);
318                 netif_start_queue(dev);
319                 goto again;
320         }
321         goto done;
322 }
323
324 #ifdef CONFIG_NET_POLL_CONTROLLER
325 static void virtnet_netpoll(struct net_device *dev)
326 {
327         struct virtnet_info *vi = netdev_priv(dev);
328
329         napi_schedule(&vi->napi);
330 }
331 #endif
332
333 static int virtnet_open(struct net_device *dev)
334 {
335         struct virtnet_info *vi = netdev_priv(dev);
336
337         napi_enable(&vi->napi);
338
339         /* If all buffers were filled by other side before we napi_enabled, we
340          * won't get another interrupt, so process any outstanding packets
341          * now.  virtnet_poll wants re-enable the queue, so we disable here.
342          * We synchronize against interrupts via NAPI_STATE_SCHED */
343         if (netif_rx_schedule_prep(dev, &vi->napi)) {
344                 vi->rvq->vq_ops->disable_cb(vi->rvq);
345                 __netif_rx_schedule(dev, &vi->napi);
346         }
347         return 0;
348 }
349
350 static int virtnet_close(struct net_device *dev)
351 {
352         struct virtnet_info *vi = netdev_priv(dev);
353
354         napi_disable(&vi->napi);
355
356         return 0;
357 }
358
359 static int virtnet_probe(struct virtio_device *vdev)
360 {
361         int err;
362         struct net_device *dev;
363         struct virtnet_info *vi;
364
365         /* Allocate ourselves a network device with room for our info */
366         dev = alloc_etherdev(sizeof(struct virtnet_info));
367         if (!dev)
368                 return -ENOMEM;
369
370         /* Set up network device as normal. */
371         dev->open = virtnet_open;
372         dev->stop = virtnet_close;
373         dev->hard_start_xmit = start_xmit;
374         dev->features = NETIF_F_HIGHDMA;
375 #ifdef CONFIG_NET_POLL_CONTROLLER
376         dev->poll_controller = virtnet_netpoll;
377 #endif
378         SET_NETDEV_DEV(dev, &vdev->dev);
379
380         /* Do we support "hardware" checksums? */
381         if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
382                 /* This opens up the world of extra features. */
383                 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
384                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
385                         dev->features |= NETIF_F_TSO | NETIF_F_UFO
386                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
387                 }
388                 /* Individual feature bits: what can host handle? */
389                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
390                         dev->features |= NETIF_F_TSO;
391                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
392                         dev->features |= NETIF_F_TSO6;
393                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
394                         dev->features |= NETIF_F_TSO_ECN;
395                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
396                         dev->features |= NETIF_F_UFO;
397         }
398
399         /* Configuration may specify what MAC to use.  Otherwise random. */
400         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
401                 vdev->config->get(vdev,
402                                   offsetof(struct virtio_net_config, mac),
403                                   dev->dev_addr, dev->addr_len);
404         } else
405                 random_ether_addr(dev->dev_addr);
406
407         /* Set up our device-specific information */
408         vi = netdev_priv(dev);
409         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
410         vi->dev = dev;
411         vi->vdev = vdev;
412         vdev->priv = vi;
413
414         /* We expect two virtqueues, receive then send. */
415         vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
416         if (IS_ERR(vi->rvq)) {
417                 err = PTR_ERR(vi->rvq);
418                 goto free;
419         }
420
421         vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
422         if (IS_ERR(vi->svq)) {
423                 err = PTR_ERR(vi->svq);
424                 goto free_recv;
425         }
426
427         /* Initialize our empty receive and send queues. */
428         skb_queue_head_init(&vi->recv);
429         skb_queue_head_init(&vi->send);
430
431         err = register_netdev(dev);
432         if (err) {
433                 pr_debug("virtio_net: registering device failed\n");
434                 goto free_send;
435         }
436
437         /* Last of all, set up some receive buffers. */
438         try_fill_recv(vi);
439
440         /* If we didn't even get one input buffer, we're useless. */
441         if (vi->num == 0) {
442                 err = -ENOMEM;
443                 goto unregister;
444         }
445
446         pr_debug("virtnet: registered device %s\n", dev->name);
447         return 0;
448
449 unregister:
450         unregister_netdev(dev);
451 free_send:
452         vdev->config->del_vq(vi->svq);
453 free_recv:
454         vdev->config->del_vq(vi->rvq);
455 free:
456         free_netdev(dev);
457         return err;
458 }
459
460 static void virtnet_remove(struct virtio_device *vdev)
461 {
462         struct virtnet_info *vi = vdev->priv;
463         struct sk_buff *skb;
464
465         /* Stop all the virtqueues. */
466         vdev->config->reset(vdev);
467
468         /* Free our skbs in send and recv queues, if any. */
469         while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
470                 kfree_skb(skb);
471                 vi->num--;
472         }
473         __skb_queue_purge(&vi->send);
474
475         BUG_ON(vi->num != 0);
476
477         vdev->config->del_vq(vi->svq);
478         vdev->config->del_vq(vi->rvq);
479         unregister_netdev(vi->dev);
480         free_netdev(vi->dev);
481 }
482
483 static struct virtio_device_id id_table[] = {
484         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
485         { 0 },
486 };
487
488 static unsigned int features[] = {
489         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
490         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
491         VIRTIO_NET_F_HOST_ECN,
492 };
493
494 static struct virtio_driver virtio_net = {
495         .feature_table = features,
496         .feature_table_size = ARRAY_SIZE(features),
497         .driver.name =  KBUILD_MODNAME,
498         .driver.owner = THIS_MODULE,
499         .id_table =     id_table,
500         .probe =        virtnet_probe,
501         .remove =       __devexit_p(virtnet_remove),
502 };
503
504 static int __init init(void)
505 {
506         return register_virtio_driver(&virtio_net);
507 }
508
509 static void __exit fini(void)
510 {
511         unregister_virtio_driver(&virtio_net);
512 }
513 module_init(init);
514 module_exit(fini);
515
516 MODULE_DEVICE_TABLE(virtio, id_table);
517 MODULE_DESCRIPTION("Virtio network driver");
518 MODULE_LICENSE("GPL");