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authorRusty Russell <rusty@rustcorp.com.au>2007-10-21 21:03:37 -0400
committerRusty Russell <rusty@rustcorp.com.au>2007-10-23 01:49:54 -0400
commit296f96fcfc160e29c01819c0c7b20c2dc8320edd (patch)
treead9c11fe2f60ca37c4bf736f919c3332cffebd9f /drivers/net/virtio_net.c
parentec3d41c4db4c21164332826ea8d812f94f2f6886 (diff)
Net driver using virtio
The network driver uses two virtqueues: one for input packets and one for output packets. This has nice locking properties (ie. we don't do any for recv vs send). TODO: 1) Big packets. 2) Multi-client devices (maybe separate driver?). 3) Resolve freeing of old xmit skbs (Christian Borntraeger) Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: netdev@vger.kernel.org
Diffstat (limited to 'drivers/net/virtio_net.c')
-rw-r--r--drivers/net/virtio_net.c435
1 files changed, 435 insertions, 0 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
new file mode 100644
index 000000000000..e396c9d2af8d
--- /dev/null
+++ b/drivers/net/virtio_net.c
@@ -0,0 +1,435 @@
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/* FIXME: MTU in config. */
28#define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
29
30struct virtnet_info
31{
32 struct virtio_device *vdev;
33 struct virtqueue *rvq, *svq;
34 struct net_device *dev;
35 struct napi_struct napi;
36
37 /* Number of input buffers, and max we've ever had. */
38 unsigned int num, max;
39
40 /* Receive & send queues. */
41 struct sk_buff_head recv;
42 struct sk_buff_head send;
43};
44
45static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
46{
47 return (struct virtio_net_hdr *)skb->cb;
48}
49
50static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
51{
52 sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
53}
54
55static bool skb_xmit_done(struct virtqueue *rvq)
56{
57 struct virtnet_info *vi = rvq->vdev->priv;
58
59 /* In case we were waiting for output buffers. */
60 netif_wake_queue(vi->dev);
61 return true;
62}
63
64static void receive_skb(struct net_device *dev, struct sk_buff *skb,
65 unsigned len)
66{
67 struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
68
69 if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
70 pr_debug("%s: short packet %i\n", dev->name, len);
71 dev->stats.rx_length_errors++;
72 goto drop;
73 }
74 len -= sizeof(struct virtio_net_hdr);
75 BUG_ON(len > MAX_PACKET_LEN);
76
77 skb_trim(skb, len);
78 skb->protocol = eth_type_trans(skb, dev);
79 pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
80 ntohs(skb->protocol), skb->len, skb->pkt_type);
81 dev->stats.rx_bytes += skb->len;
82 dev->stats.rx_packets++;
83
84 if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
85 pr_debug("Needs csum!\n");
86 skb->ip_summed = CHECKSUM_PARTIAL;
87 skb->csum_start = hdr->csum_start;
88 skb->csum_offset = hdr->csum_offset;
89 if (skb->csum_start > skb->len - 2
90 || skb->csum_offset > skb->len - 2) {
91 if (net_ratelimit())
92 printk(KERN_WARNING "%s: csum=%u/%u len=%u\n",
93 dev->name, skb->csum_start,
94 skb->csum_offset, skb->len);
95 goto frame_err;
96 }
97 }
98
99 if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
100 pr_debug("GSO!\n");
101 switch (hdr->gso_type) {
102 case VIRTIO_NET_HDR_GSO_TCPV4:
103 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
104 break;
105 case VIRTIO_NET_HDR_GSO_TCPV4_ECN:
106 skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN;
107 break;
108 case VIRTIO_NET_HDR_GSO_UDP:
109 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
110 break;
111 case VIRTIO_NET_HDR_GSO_TCPV6:
112 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
113 break;
114 default:
115 if (net_ratelimit())
116 printk(KERN_WARNING "%s: bad gso type %u.\n",
117 dev->name, hdr->gso_type);
118 goto frame_err;
119 }
120
121 skb_shinfo(skb)->gso_size = hdr->gso_size;
122 if (skb_shinfo(skb)->gso_size == 0) {
123 if (net_ratelimit())
124 printk(KERN_WARNING "%s: zero gso size.\n",
125 dev->name);
126 goto frame_err;
127 }
128
129 /* Header must be checked, and gso_segs computed. */
130 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
131 skb_shinfo(skb)->gso_segs = 0;
132 }
133
134 netif_receive_skb(skb);
135 return;
136
137frame_err:
138 dev->stats.rx_frame_errors++;
139drop:
140 dev_kfree_skb(skb);
141}
142
143static void try_fill_recv(struct virtnet_info *vi)
144{
145 struct sk_buff *skb;
146 struct scatterlist sg[1+MAX_SKB_FRAGS];
147 int num, err;
148
149 for (;;) {
150 skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
151 if (unlikely(!skb))
152 break;
153
154 skb_put(skb, MAX_PACKET_LEN);
155 vnet_hdr_to_sg(sg, skb);
156 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
157 skb_queue_head(&vi->recv, skb);
158
159 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
160 if (err) {
161 skb_unlink(skb, &vi->recv);
162 kfree_skb(skb);
163 break;
164 }
165 vi->num++;
166 }
167 if (unlikely(vi->num > vi->max))
168 vi->max = vi->num;
169 vi->rvq->vq_ops->kick(vi->rvq);
170}
171
172static bool skb_recv_done(struct virtqueue *rvq)
173{
174 struct virtnet_info *vi = rvq->vdev->priv;
175 netif_rx_schedule(vi->dev, &vi->napi);
176 /* Suppress further interrupts. */
177 return false;
178}
179
180static int virtnet_poll(struct napi_struct *napi, int budget)
181{
182 struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
183 struct sk_buff *skb = NULL;
184 unsigned int len, received = 0;
185
186again:
187 while (received < budget &&
188 (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
189 __skb_unlink(skb, &vi->recv);
190 receive_skb(vi->dev, skb, len);
191 vi->num--;
192 received++;
193 }
194
195 /* FIXME: If we oom and completely run out of inbufs, we need
196 * to start a timer trying to fill more. */
197 if (vi->num < vi->max / 2)
198 try_fill_recv(vi);
199
200 /* All done? */
201 if (!skb) {
202 netif_rx_complete(vi->dev, napi);
203 if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq))
204 && netif_rx_reschedule(vi->dev, napi))
205 goto again;
206 }
207
208 return received;
209}
210
211static void free_old_xmit_skbs(struct virtnet_info *vi)
212{
213 struct sk_buff *skb;
214 unsigned int len;
215
216 while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
217 pr_debug("Sent skb %p\n", skb);
218 __skb_unlink(skb, &vi->send);
219 vi->dev->stats.tx_bytes += len;
220 vi->dev->stats.tx_packets++;
221 kfree_skb(skb);
222 }
223}
224
225static int start_xmit(struct sk_buff *skb, struct net_device *dev)
226{
227 struct virtnet_info *vi = netdev_priv(dev);
228 int num, err;
229 struct scatterlist sg[1+MAX_SKB_FRAGS];
230 struct virtio_net_hdr *hdr;
231 const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
232 DECLARE_MAC_BUF(mac);
233
234 pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));
235
236 free_old_xmit_skbs(vi);
237
238 /* Encode metadata header at front. */
239 hdr = skb_vnet_hdr(skb);
240 if (skb->ip_summed == CHECKSUM_PARTIAL) {
241 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
242 hdr->csum_start = skb->csum_start - skb_headroom(skb);
243 hdr->csum_offset = skb->csum_offset;
244 } else {
245 hdr->flags = 0;
246 hdr->csum_offset = hdr->csum_start = 0;
247 }
248
249 if (skb_is_gso(skb)) {
250 hdr->gso_size = skb_shinfo(skb)->gso_size;
251 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
252 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN;
253 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
254 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
255 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
256 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
257 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
258 hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
259 else
260 BUG();
261 } else {
262 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
263 hdr->gso_size = 0;
264 }
265
266 vnet_hdr_to_sg(sg, skb);
267 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
268 __skb_queue_head(&vi->send, skb);
269 err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
270 if (err) {
271 pr_debug("%s: virtio not prepared to send\n", dev->name);
272 skb_unlink(skb, &vi->send);
273 netif_stop_queue(dev);
274 return NETDEV_TX_BUSY;
275 }
276 vi->svq->vq_ops->kick(vi->svq);
277
278 return 0;
279}
280
281static int virtnet_open(struct net_device *dev)
282{
283 struct virtnet_info *vi = netdev_priv(dev);
284
285 try_fill_recv(vi);
286
287 /* If we didn't even get one input buffer, we're useless. */
288 if (vi->num == 0)
289 return -ENOMEM;
290
291 napi_enable(&vi->napi);
292 return 0;
293}
294
295static int virtnet_close(struct net_device *dev)
296{
297 struct virtnet_info *vi = netdev_priv(dev);
298 struct sk_buff *skb;
299
300 napi_disable(&vi->napi);
301
302 /* networking core has neutered skb_xmit_done/skb_recv_done, so don't
303 * worry about races vs. get(). */
304 vi->rvq->vq_ops->shutdown(vi->rvq);
305 while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
306 kfree_skb(skb);
307 vi->num--;
308 }
309 vi->svq->vq_ops->shutdown(vi->svq);
310 while ((skb = __skb_dequeue(&vi->send)) != NULL)
311 kfree_skb(skb);
312
313 BUG_ON(vi->num != 0);
314 return 0;
315}
316
317static int virtnet_probe(struct virtio_device *vdev)
318{
319 int err;
320 unsigned int len;
321 struct net_device *dev;
322 struct virtnet_info *vi;
323 void *token;
324
325 /* Allocate ourselves a network device with room for our info */
326 dev = alloc_etherdev(sizeof(struct virtnet_info));
327 if (!dev)
328 return -ENOMEM;
329
330 /* Set up network device as normal. */
331 ether_setup(dev);
332 dev->open = virtnet_open;
333 dev->stop = virtnet_close;
334 dev->hard_start_xmit = start_xmit;
335 dev->features = NETIF_F_HIGHDMA;
336 SET_NETDEV_DEV(dev, &vdev->dev);
337
338 /* Do we support "hardware" checksums? */
339 token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_F, &len);
340 if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_NO_CSUM)) {
341 /* This opens up the world of extra features. */
342 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
343 if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4))
344 dev->features |= NETIF_F_TSO;
345 if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_UFO))
346 dev->features |= NETIF_F_UFO;
347 if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4_ECN))
348 dev->features |= NETIF_F_TSO_ECN;
349 if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO6))
350 dev->features |= NETIF_F_TSO6;
351 }
352
353 /* Configuration may specify what MAC to use. Otherwise random. */
354 token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_MAC_F, &len);
355 if (token) {
356 dev->addr_len = len;
357 vdev->config->get(vdev, token, dev->dev_addr, len);
358 } else
359 random_ether_addr(dev->dev_addr);
360
361 /* Set up our device-specific information */
362 vi = netdev_priv(dev);
363 netif_napi_add(dev, &vi->napi, virtnet_poll, 16);
364 vi->dev = dev;
365 vi->vdev = vdev;
366
367 /* We expect two virtqueues, receive then send. */
368 vi->rvq = vdev->config->find_vq(vdev, skb_recv_done);
369 if (IS_ERR(vi->rvq)) {
370 err = PTR_ERR(vi->rvq);
371 goto free;
372 }
373
374 vi->svq = vdev->config->find_vq(vdev, skb_xmit_done);
375 if (IS_ERR(vi->svq)) {
376 err = PTR_ERR(vi->svq);
377 goto free_recv;
378 }
379
380 /* Initialize our empty receive and send queues. */
381 skb_queue_head_init(&vi->recv);
382 skb_queue_head_init(&vi->send);
383
384 err = register_netdev(dev);
385 if (err) {
386 pr_debug("virtio_net: registering device failed\n");
387 goto free_send;
388 }
389 pr_debug("virtnet: registered device %s\n", dev->name);
390 vdev->priv = vi;
391 return 0;
392
393free_send:
394 vdev->config->del_vq(vi->svq);
395free_recv:
396 vdev->config->del_vq(vi->rvq);
397free:
398 free_netdev(dev);
399 return err;
400}
401
402static void virtnet_remove(struct virtio_device *vdev)
403{
404 unregister_netdev(vdev->priv);
405 free_netdev(vdev->priv);
406}
407
408static struct virtio_device_id id_table[] = {
409 { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
410 { 0 },
411};
412
413static struct virtio_driver virtio_net = {
414 .driver.name = KBUILD_MODNAME,
415 .driver.owner = THIS_MODULE,
416 .id_table = id_table,
417 .probe = virtnet_probe,
418 .remove = __devexit_p(virtnet_remove),
419};
420
421static int __init init(void)
422{
423 return register_virtio_driver(&virtio_net);
424}
425
426static void __exit fini(void)
427{
428 unregister_virtio_driver(&virtio_net);
429}
430module_init(init);
431module_exit(fini);
432
433MODULE_DEVICE_TABLE(virtio, id_table);
434MODULE_DESCRIPTION("Virtio network driver");
435MODULE_LICENSE("GPL");