xref: /openbmc/linux/drivers/net/virtio_net.c (revision 384740dc)
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 
28 static int napi_weight = 128;
29 module_param(napi_weight, int, 0444);
30 
31 static int csum = 1, gso = 1;
32 module_param(csum, bool, 0444);
33 module_param(gso, bool, 0444);
34 
35 /* FIXME: MTU in config. */
36 #define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
37 
38 struct virtnet_info
39 {
40 	struct virtio_device *vdev;
41 	struct virtqueue *rvq, *svq;
42 	struct net_device *dev;
43 	struct napi_struct napi;
44 
45 	/* The skb we couldn't send because buffers were full. */
46 	struct sk_buff *last_xmit_skb;
47 
48 	/* If we need to free in a timer, this is it. */
49 	struct timer_list xmit_free_timer;
50 
51 	/* Number of input buffers, and max we've ever had. */
52 	unsigned int num, max;
53 
54 	/* For cleaning up after transmission. */
55 	struct tasklet_struct tasklet;
56 	bool free_in_tasklet;
57 
58 	/* I like... big packets and I cannot lie! */
59 	bool big_packets;
60 
61 	/* Receive & send queues. */
62 	struct sk_buff_head recv;
63 	struct sk_buff_head send;
64 
65 	/* Chain pages by the private ptr. */
66 	struct page *pages;
67 };
68 
69 static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
70 {
71 	return (struct virtio_net_hdr *)skb->cb;
72 }
73 
74 static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
75 {
76 	sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
77 }
78 
79 static void give_a_page(struct virtnet_info *vi, struct page *page)
80 {
81 	page->private = (unsigned long)vi->pages;
82 	vi->pages = page;
83 }
84 
85 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
86 {
87 	struct page *p = vi->pages;
88 
89 	if (p)
90 		vi->pages = (struct page *)p->private;
91 	else
92 		p = alloc_page(gfp_mask);
93 	return p;
94 }
95 
96 static void skb_xmit_done(struct virtqueue *svq)
97 {
98 	struct virtnet_info *vi = svq->vdev->priv;
99 
100 	/* Suppress further interrupts. */
101 	svq->vq_ops->disable_cb(svq);
102 
103 	/* We were probably waiting for more output buffers. */
104 	netif_wake_queue(vi->dev);
105 
106 	/* Make sure we re-xmit last_xmit_skb: if there are no more packets
107 	 * queued, start_xmit won't be called. */
108 	tasklet_schedule(&vi->tasklet);
109 }
110 
111 static void receive_skb(struct net_device *dev, struct sk_buff *skb,
112 			unsigned len)
113 {
114 	struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
115 	int err;
116 
117 	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
118 		pr_debug("%s: short packet %i\n", dev->name, len);
119 		dev->stats.rx_length_errors++;
120 		goto drop;
121 	}
122 	len -= sizeof(struct virtio_net_hdr);
123 
124 	if (len <= MAX_PACKET_LEN) {
125 		unsigned int i;
126 
127 		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
128 			give_a_page(dev->priv, skb_shinfo(skb)->frags[i].page);
129 		skb->data_len = 0;
130 		skb_shinfo(skb)->nr_frags = 0;
131 	}
132 
133 	err = pskb_trim(skb, len);
134 	if (err) {
135 		pr_debug("%s: pskb_trim failed %i %d\n", dev->name, len, err);
136 		dev->stats.rx_dropped++;
137 		goto drop;
138 	}
139 	skb->truesize += skb->data_len;
140 	dev->stats.rx_bytes += skb->len;
141 	dev->stats.rx_packets++;
142 
143 	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
144 		pr_debug("Needs csum!\n");
145 		if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
146 			goto frame_err;
147 	}
148 
149 	skb->protocol = eth_type_trans(skb, dev);
150 	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
151 		 ntohs(skb->protocol), skb->len, skb->pkt_type);
152 
153 	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
154 		pr_debug("GSO!\n");
155 		switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
156 		case VIRTIO_NET_HDR_GSO_TCPV4:
157 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
158 			break;
159 		case VIRTIO_NET_HDR_GSO_UDP:
160 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
161 			break;
162 		case VIRTIO_NET_HDR_GSO_TCPV6:
163 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
164 			break;
165 		default:
166 			if (net_ratelimit())
167 				printk(KERN_WARNING "%s: bad gso type %u.\n",
168 				       dev->name, hdr->gso_type);
169 			goto frame_err;
170 		}
171 
172 		if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
173 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
174 
175 		skb_shinfo(skb)->gso_size = hdr->gso_size;
176 		if (skb_shinfo(skb)->gso_size == 0) {
177 			if (net_ratelimit())
178 				printk(KERN_WARNING "%s: zero gso size.\n",
179 				       dev->name);
180 			goto frame_err;
181 		}
182 
183 		/* Header must be checked, and gso_segs computed. */
184 		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
185 		skb_shinfo(skb)->gso_segs = 0;
186 	}
187 
188 	netif_receive_skb(skb);
189 	return;
190 
191 frame_err:
192 	dev->stats.rx_frame_errors++;
193 drop:
194 	dev_kfree_skb(skb);
195 }
196 
197 static void try_fill_recv(struct virtnet_info *vi)
198 {
199 	struct sk_buff *skb;
200 	struct scatterlist sg[2+MAX_SKB_FRAGS];
201 	int num, err, i;
202 
203 	sg_init_table(sg, 2+MAX_SKB_FRAGS);
204 	for (;;) {
205 		skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
206 		if (unlikely(!skb))
207 			break;
208 
209 		skb_put(skb, MAX_PACKET_LEN);
210 		vnet_hdr_to_sg(sg, skb);
211 
212 		if (vi->big_packets) {
213 			for (i = 0; i < MAX_SKB_FRAGS; i++) {
214 				skb_frag_t *f = &skb_shinfo(skb)->frags[i];
215 				f->page = get_a_page(vi, GFP_ATOMIC);
216 				if (!f->page)
217 					break;
218 
219 				f->page_offset = 0;
220 				f->size = PAGE_SIZE;
221 
222 				skb->data_len += PAGE_SIZE;
223 				skb->len += PAGE_SIZE;
224 
225 				skb_shinfo(skb)->nr_frags++;
226 			}
227 		}
228 
229 		num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
230 		skb_queue_head(&vi->recv, skb);
231 
232 		err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
233 		if (err) {
234 			skb_unlink(skb, &vi->recv);
235 			kfree_skb(skb);
236 			break;
237 		}
238 		vi->num++;
239 	}
240 	if (unlikely(vi->num > vi->max))
241 		vi->max = vi->num;
242 	vi->rvq->vq_ops->kick(vi->rvq);
243 }
244 
245 static void skb_recv_done(struct virtqueue *rvq)
246 {
247 	struct virtnet_info *vi = rvq->vdev->priv;
248 	/* Schedule NAPI, Suppress further interrupts if successful. */
249 	if (netif_rx_schedule_prep(vi->dev, &vi->napi)) {
250 		rvq->vq_ops->disable_cb(rvq);
251 		__netif_rx_schedule(vi->dev, &vi->napi);
252 	}
253 }
254 
255 static int virtnet_poll(struct napi_struct *napi, int budget)
256 {
257 	struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
258 	struct sk_buff *skb = NULL;
259 	unsigned int len, received = 0;
260 
261 again:
262 	while (received < budget &&
263 	       (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
264 		__skb_unlink(skb, &vi->recv);
265 		receive_skb(vi->dev, skb, len);
266 		vi->num--;
267 		received++;
268 	}
269 
270 	/* FIXME: If we oom and completely run out of inbufs, we need
271 	 * to start a timer trying to fill more. */
272 	if (vi->num < vi->max / 2)
273 		try_fill_recv(vi);
274 
275 	/* Out of packets? */
276 	if (received < budget) {
277 		netif_rx_complete(vi->dev, napi);
278 		if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
279 		    && napi_schedule_prep(napi)) {
280 			vi->rvq->vq_ops->disable_cb(vi->rvq);
281 			__netif_rx_schedule(vi->dev, napi);
282 			goto again;
283 		}
284 	}
285 
286 	return received;
287 }
288 
289 static void free_old_xmit_skbs(struct virtnet_info *vi)
290 {
291 	struct sk_buff *skb;
292 	unsigned int len;
293 
294 	while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
295 		pr_debug("Sent skb %p\n", skb);
296 		__skb_unlink(skb, &vi->send);
297 		vi->dev->stats.tx_bytes += skb->len;
298 		vi->dev->stats.tx_packets++;
299 		kfree_skb(skb);
300 	}
301 }
302 
303 /* If the virtio transport doesn't always notify us when all in-flight packets
304  * are consumed, we fall back to using this function on a timer to free them. */
305 static void xmit_free(unsigned long data)
306 {
307 	struct virtnet_info *vi = (void *)data;
308 
309 	netif_tx_lock(vi->dev);
310 
311 	free_old_xmit_skbs(vi);
312 
313 	if (!skb_queue_empty(&vi->send))
314 		mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
315 
316 	netif_tx_unlock(vi->dev);
317 }
318 
319 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
320 {
321 	int num, err;
322 	struct scatterlist sg[2+MAX_SKB_FRAGS];
323 	struct virtio_net_hdr *hdr;
324 	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
325 
326 	sg_init_table(sg, 2+MAX_SKB_FRAGS);
327 
328 	pr_debug("%s: xmit %p " MAC_FMT "\n", vi->dev->name, skb,
329 		 dest[0], dest[1], dest[2],
330 		 dest[3], dest[4], dest[5]);
331 
332 	/* Encode metadata header at front. */
333 	hdr = skb_vnet_hdr(skb);
334 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
335 		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
336 		hdr->csum_start = skb->csum_start - skb_headroom(skb);
337 		hdr->csum_offset = skb->csum_offset;
338 	} else {
339 		hdr->flags = 0;
340 		hdr->csum_offset = hdr->csum_start = 0;
341 	}
342 
343 	if (skb_is_gso(skb)) {
344 		hdr->hdr_len = skb_transport_header(skb) - skb->data;
345 		hdr->gso_size = skb_shinfo(skb)->gso_size;
346 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
347 			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
348 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
349 			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
350 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
351 			hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
352 		else
353 			BUG();
354 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
355 			hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
356 	} else {
357 		hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
358 		hdr->gso_size = hdr->hdr_len = 0;
359 	}
360 
361 	vnet_hdr_to_sg(sg, skb);
362 	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
363 
364 	err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
365 	if (!err && !vi->free_in_tasklet)
366 		mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
367 
368 	return err;
369 }
370 
371 static void xmit_tasklet(unsigned long data)
372 {
373 	struct virtnet_info *vi = (void *)data;
374 
375 	netif_tx_lock_bh(vi->dev);
376 	if (vi->last_xmit_skb && xmit_skb(vi, vi->last_xmit_skb) == 0) {
377 		vi->svq->vq_ops->kick(vi->svq);
378 		vi->last_xmit_skb = NULL;
379 	}
380 	if (vi->free_in_tasklet)
381 		free_old_xmit_skbs(vi);
382 	netif_tx_unlock_bh(vi->dev);
383 }
384 
385 static int start_xmit(struct sk_buff *skb, struct net_device *dev)
386 {
387 	struct virtnet_info *vi = netdev_priv(dev);
388 
389 again:
390 	/* Free up any pending old buffers before queueing new ones. */
391 	free_old_xmit_skbs(vi);
392 
393 	/* If we has a buffer left over from last time, send it now. */
394 	if (unlikely(vi->last_xmit_skb) &&
395 	    xmit_skb(vi, vi->last_xmit_skb) != 0)
396 		goto stop_queue;
397 
398 	vi->last_xmit_skb = NULL;
399 
400 	/* Put new one in send queue and do transmit */
401 	if (likely(skb)) {
402 		__skb_queue_head(&vi->send, skb);
403 		if (xmit_skb(vi, skb) != 0) {
404 			vi->last_xmit_skb = skb;
405 			skb = NULL;
406 			goto stop_queue;
407 		}
408 	}
409 done:
410 	vi->svq->vq_ops->kick(vi->svq);
411 	return NETDEV_TX_OK;
412 
413 stop_queue:
414 	pr_debug("%s: virtio not prepared to send\n", dev->name);
415 	netif_stop_queue(dev);
416 
417 	/* Activate callback for using skbs: if this returns false it
418 	 * means some were used in the meantime. */
419 	if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
420 		vi->svq->vq_ops->disable_cb(vi->svq);
421 		netif_start_queue(dev);
422 		goto again;
423 	}
424 	if (skb) {
425 		/* Drop this skb: we only queue one. */
426 		vi->dev->stats.tx_dropped++;
427 		kfree_skb(skb);
428 	}
429 	goto done;
430 }
431 
432 #ifdef CONFIG_NET_POLL_CONTROLLER
433 static void virtnet_netpoll(struct net_device *dev)
434 {
435 	struct virtnet_info *vi = netdev_priv(dev);
436 
437 	napi_schedule(&vi->napi);
438 }
439 #endif
440 
441 static int virtnet_open(struct net_device *dev)
442 {
443 	struct virtnet_info *vi = netdev_priv(dev);
444 
445 	napi_enable(&vi->napi);
446 
447 	/* If all buffers were filled by other side before we napi_enabled, we
448 	 * won't get another interrupt, so process any outstanding packets
449 	 * now.  virtnet_poll wants re-enable the queue, so we disable here.
450 	 * We synchronize against interrupts via NAPI_STATE_SCHED */
451 	if (netif_rx_schedule_prep(dev, &vi->napi)) {
452 		vi->rvq->vq_ops->disable_cb(vi->rvq);
453 		__netif_rx_schedule(dev, &vi->napi);
454 	}
455 	return 0;
456 }
457 
458 static int virtnet_close(struct net_device *dev)
459 {
460 	struct virtnet_info *vi = netdev_priv(dev);
461 
462 	napi_disable(&vi->napi);
463 
464 	return 0;
465 }
466 
467 static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
468 {
469 	struct virtnet_info *vi = netdev_priv(dev);
470 	struct virtio_device *vdev = vi->vdev;
471 
472 	if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM))
473 		return -ENOSYS;
474 
475 	return ethtool_op_set_tx_hw_csum(dev, data);
476 }
477 
478 static struct ethtool_ops virtnet_ethtool_ops = {
479 	.set_tx_csum = virtnet_set_tx_csum,
480 	.set_sg = ethtool_op_set_sg,
481 };
482 
483 static int virtnet_probe(struct virtio_device *vdev)
484 {
485 	int err;
486 	struct net_device *dev;
487 	struct virtnet_info *vi;
488 
489 	/* Allocate ourselves a network device with room for our info */
490 	dev = alloc_etherdev(sizeof(struct virtnet_info));
491 	if (!dev)
492 		return -ENOMEM;
493 
494 	/* Set up network device as normal. */
495 	dev->open = virtnet_open;
496 	dev->stop = virtnet_close;
497 	dev->hard_start_xmit = start_xmit;
498 	dev->features = NETIF_F_HIGHDMA;
499 #ifdef CONFIG_NET_POLL_CONTROLLER
500 	dev->poll_controller = virtnet_netpoll;
501 #endif
502 	SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
503 	SET_NETDEV_DEV(dev, &vdev->dev);
504 
505 	/* Do we support "hardware" checksums? */
506 	if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
507 		/* This opens up the world of extra features. */
508 		dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
509 		if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
510 			dev->features |= NETIF_F_TSO | NETIF_F_UFO
511 				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
512 		}
513 		/* Individual feature bits: what can host handle? */
514 		if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
515 			dev->features |= NETIF_F_TSO;
516 		if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
517 			dev->features |= NETIF_F_TSO6;
518 		if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
519 			dev->features |= NETIF_F_TSO_ECN;
520 		if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
521 			dev->features |= NETIF_F_UFO;
522 	}
523 
524 	/* Configuration may specify what MAC to use.  Otherwise random. */
525 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
526 		vdev->config->get(vdev,
527 				  offsetof(struct virtio_net_config, mac),
528 				  dev->dev_addr, dev->addr_len);
529 	} else
530 		random_ether_addr(dev->dev_addr);
531 
532 	/* Set up our device-specific information */
533 	vi = netdev_priv(dev);
534 	netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
535 	vi->dev = dev;
536 	vi->vdev = vdev;
537 	vdev->priv = vi;
538 	vi->pages = NULL;
539 
540 	/* If they give us a callback when all buffers are done, we don't need
541 	 * the timer. */
542 	vi->free_in_tasklet = virtio_has_feature(vdev,VIRTIO_F_NOTIFY_ON_EMPTY);
543 
544 	/* If we can receive ANY GSO packets, we must allocate large ones. */
545 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4)
546 	    || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6)
547 	    || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
548 		vi->big_packets = true;
549 
550 	/* We expect two virtqueues, receive then send. */
551 	vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
552 	if (IS_ERR(vi->rvq)) {
553 		err = PTR_ERR(vi->rvq);
554 		goto free;
555 	}
556 
557 	vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
558 	if (IS_ERR(vi->svq)) {
559 		err = PTR_ERR(vi->svq);
560 		goto free_recv;
561 	}
562 
563 	/* Initialize our empty receive and send queues. */
564 	skb_queue_head_init(&vi->recv);
565 	skb_queue_head_init(&vi->send);
566 
567 	tasklet_init(&vi->tasklet, xmit_tasklet, (unsigned long)vi);
568 
569 	if (!vi->free_in_tasklet)
570 		setup_timer(&vi->xmit_free_timer, xmit_free, (unsigned long)vi);
571 
572 	err = register_netdev(dev);
573 	if (err) {
574 		pr_debug("virtio_net: registering device failed\n");
575 		goto free_send;
576 	}
577 
578 	/* Last of all, set up some receive buffers. */
579 	try_fill_recv(vi);
580 
581 	/* If we didn't even get one input buffer, we're useless. */
582 	if (vi->num == 0) {
583 		err = -ENOMEM;
584 		goto unregister;
585 	}
586 
587 	pr_debug("virtnet: registered device %s\n", dev->name);
588 	return 0;
589 
590 unregister:
591 	unregister_netdev(dev);
592 free_send:
593 	vdev->config->del_vq(vi->svq);
594 free_recv:
595 	vdev->config->del_vq(vi->rvq);
596 free:
597 	free_netdev(dev);
598 	return err;
599 }
600 
601 static void virtnet_remove(struct virtio_device *vdev)
602 {
603 	struct virtnet_info *vi = vdev->priv;
604 	struct sk_buff *skb;
605 
606 	/* Stop all the virtqueues. */
607 	vdev->config->reset(vdev);
608 
609 	if (!vi->free_in_tasklet)
610 		del_timer_sync(&vi->xmit_free_timer);
611 
612 	/* Free our skbs in send and recv queues, if any. */
613 	while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
614 		kfree_skb(skb);
615 		vi->num--;
616 	}
617 	__skb_queue_purge(&vi->send);
618 
619 	BUG_ON(vi->num != 0);
620 
621 	vdev->config->del_vq(vi->svq);
622 	vdev->config->del_vq(vi->rvq);
623 	unregister_netdev(vi->dev);
624 
625 	while (vi->pages)
626 		__free_pages(get_a_page(vi, GFP_KERNEL), 0);
627 
628 	free_netdev(vi->dev);
629 }
630 
631 static struct virtio_device_id id_table[] = {
632 	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
633 	{ 0 },
634 };
635 
636 static unsigned int features[] = {
637 	VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
638 	VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
639 	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
640 	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
641 	VIRTIO_NET_F_GUEST_ECN, /* We don't yet handle UFO input. */
642 	VIRTIO_F_NOTIFY_ON_EMPTY,
643 };
644 
645 static struct virtio_driver virtio_net = {
646 	.feature_table = features,
647 	.feature_table_size = ARRAY_SIZE(features),
648 	.driver.name =	KBUILD_MODNAME,
649 	.driver.owner =	THIS_MODULE,
650 	.id_table =	id_table,
651 	.probe =	virtnet_probe,
652 	.remove =	__devexit_p(virtnet_remove),
653 };
654 
655 static int __init init(void)
656 {
657 	return register_virtio_driver(&virtio_net);
658 }
659 
660 static void __exit fini(void)
661 {
662 	unregister_virtio_driver(&virtio_net);
663 }
664 module_init(init);
665 module_exit(fini);
666 
667 MODULE_DEVICE_TABLE(virtio, id_table);
668 MODULE_DESCRIPTION("Virtio network driver");
669 MODULE_LICENSE("GPL");
670