xref: /openbmc/linux/drivers/net/virtio_net.c (revision 95e9fd10)
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 #include <linux/slab.h>
29 
30 static int napi_weight = 128;
31 module_param(napi_weight, int, 0444);
32 
33 static bool csum = true, gso = true;
34 module_param(csum, bool, 0444);
35 module_param(gso, bool, 0444);
36 
37 /* FIXME: MTU in config. */
38 #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
39 #define GOOD_COPY_LEN	128
40 
41 #define VIRTNET_SEND_COMMAND_SG_MAX    2
42 #define VIRTNET_DRIVER_VERSION "1.0.0"
43 
44 struct virtnet_stats {
45 	struct u64_stats_sync tx_syncp;
46 	struct u64_stats_sync rx_syncp;
47 	u64 tx_bytes;
48 	u64 tx_packets;
49 
50 	u64 rx_bytes;
51 	u64 rx_packets;
52 };
53 
54 struct virtnet_info {
55 	struct virtio_device *vdev;
56 	struct virtqueue *rvq, *svq, *cvq;
57 	struct net_device *dev;
58 	struct napi_struct napi;
59 	unsigned int status;
60 
61 	/* Number of input buffers, and max we've ever had. */
62 	unsigned int num, max;
63 
64 	/* I like... big packets and I cannot lie! */
65 	bool big_packets;
66 
67 	/* Host will merge rx buffers for big packets (shake it! shake it!) */
68 	bool mergeable_rx_bufs;
69 
70 	/* enable config space updates */
71 	bool config_enable;
72 
73 	/* Active statistics */
74 	struct virtnet_stats __percpu *stats;
75 
76 	/* Work struct for refilling if we run low on memory. */
77 	struct delayed_work refill;
78 
79 	/* Work struct for config space updates */
80 	struct work_struct config_work;
81 
82 	/* Lock for config space updates */
83 	struct mutex config_lock;
84 
85 	/* Chain pages by the private ptr. */
86 	struct page *pages;
87 
88 	/* fragments + linear part + virtio header */
89 	struct scatterlist rx_sg[MAX_SKB_FRAGS + 2];
90 	struct scatterlist tx_sg[MAX_SKB_FRAGS + 2];
91 };
92 
93 struct skb_vnet_hdr {
94 	union {
95 		struct virtio_net_hdr hdr;
96 		struct virtio_net_hdr_mrg_rxbuf mhdr;
97 	};
98 	unsigned int num_sg;
99 };
100 
101 struct padded_vnet_hdr {
102 	struct virtio_net_hdr hdr;
103 	/*
104 	 * virtio_net_hdr should be in a separated sg buffer because of a
105 	 * QEMU bug, and data sg buffer shares same page with this header sg.
106 	 * This padding makes next sg 16 byte aligned after virtio_net_hdr.
107 	 */
108 	char padding[6];
109 };
110 
111 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
112 {
113 	return (struct skb_vnet_hdr *)skb->cb;
114 }
115 
116 /*
117  * private is used to chain pages for big packets, put the whole
118  * most recent used list in the beginning for reuse
119  */
120 static void give_pages(struct virtnet_info *vi, struct page *page)
121 {
122 	struct page *end;
123 
124 	/* Find end of list, sew whole thing into vi->pages. */
125 	for (end = page; end->private; end = (struct page *)end->private);
126 	end->private = (unsigned long)vi->pages;
127 	vi->pages = page;
128 }
129 
130 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
131 {
132 	struct page *p = vi->pages;
133 
134 	if (p) {
135 		vi->pages = (struct page *)p->private;
136 		/* clear private here, it is used to chain pages */
137 		p->private = 0;
138 	} else
139 		p = alloc_page(gfp_mask);
140 	return p;
141 }
142 
143 static void skb_xmit_done(struct virtqueue *svq)
144 {
145 	struct virtnet_info *vi = svq->vdev->priv;
146 
147 	/* Suppress further interrupts. */
148 	virtqueue_disable_cb(svq);
149 
150 	/* We were probably waiting for more output buffers. */
151 	netif_wake_queue(vi->dev);
152 }
153 
154 static void set_skb_frag(struct sk_buff *skb, struct page *page,
155 			 unsigned int offset, unsigned int *len)
156 {
157 	int size = min((unsigned)PAGE_SIZE - offset, *len);
158 	int i = skb_shinfo(skb)->nr_frags;
159 
160 	__skb_fill_page_desc(skb, i, page, offset, size);
161 
162 	skb->data_len += size;
163 	skb->len += size;
164 	skb->truesize += PAGE_SIZE;
165 	skb_shinfo(skb)->nr_frags++;
166 	*len -= size;
167 }
168 
169 /* Called from bottom half context */
170 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
171 				   struct page *page, unsigned int len)
172 {
173 	struct sk_buff *skb;
174 	struct skb_vnet_hdr *hdr;
175 	unsigned int copy, hdr_len, offset;
176 	char *p;
177 
178 	p = page_address(page);
179 
180 	/* copy small packet so we can reuse these pages for small data */
181 	skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
182 	if (unlikely(!skb))
183 		return NULL;
184 
185 	hdr = skb_vnet_hdr(skb);
186 
187 	if (vi->mergeable_rx_bufs) {
188 		hdr_len = sizeof hdr->mhdr;
189 		offset = hdr_len;
190 	} else {
191 		hdr_len = sizeof hdr->hdr;
192 		offset = sizeof(struct padded_vnet_hdr);
193 	}
194 
195 	memcpy(hdr, p, hdr_len);
196 
197 	len -= hdr_len;
198 	p += offset;
199 
200 	copy = len;
201 	if (copy > skb_tailroom(skb))
202 		copy = skb_tailroom(skb);
203 	memcpy(skb_put(skb, copy), p, copy);
204 
205 	len -= copy;
206 	offset += copy;
207 
208 	/*
209 	 * Verify that we can indeed put this data into a skb.
210 	 * This is here to handle cases when the device erroneously
211 	 * tries to receive more than is possible. This is usually
212 	 * the case of a broken device.
213 	 */
214 	if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
215 		if (net_ratelimit())
216 			pr_debug("%s: too much data\n", skb->dev->name);
217 		dev_kfree_skb(skb);
218 		return NULL;
219 	}
220 
221 	while (len) {
222 		set_skb_frag(skb, page, offset, &len);
223 		page = (struct page *)page->private;
224 		offset = 0;
225 	}
226 
227 	if (page)
228 		give_pages(vi, page);
229 
230 	return skb;
231 }
232 
233 static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
234 {
235 	struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
236 	struct page *page;
237 	int num_buf, i, len;
238 
239 	num_buf = hdr->mhdr.num_buffers;
240 	while (--num_buf) {
241 		i = skb_shinfo(skb)->nr_frags;
242 		if (i >= MAX_SKB_FRAGS) {
243 			pr_debug("%s: packet too long\n", skb->dev->name);
244 			skb->dev->stats.rx_length_errors++;
245 			return -EINVAL;
246 		}
247 		page = virtqueue_get_buf(vi->rvq, &len);
248 		if (!page) {
249 			pr_debug("%s: rx error: %d buffers missing\n",
250 				 skb->dev->name, hdr->mhdr.num_buffers);
251 			skb->dev->stats.rx_length_errors++;
252 			return -EINVAL;
253 		}
254 
255 		if (len > PAGE_SIZE)
256 			len = PAGE_SIZE;
257 
258 		set_skb_frag(skb, page, 0, &len);
259 
260 		--vi->num;
261 	}
262 	return 0;
263 }
264 
265 static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
266 {
267 	struct virtnet_info *vi = netdev_priv(dev);
268 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
269 	struct sk_buff *skb;
270 	struct page *page;
271 	struct skb_vnet_hdr *hdr;
272 
273 	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
274 		pr_debug("%s: short packet %i\n", dev->name, len);
275 		dev->stats.rx_length_errors++;
276 		if (vi->mergeable_rx_bufs || vi->big_packets)
277 			give_pages(vi, buf);
278 		else
279 			dev_kfree_skb(buf);
280 		return;
281 	}
282 
283 	if (!vi->mergeable_rx_bufs && !vi->big_packets) {
284 		skb = buf;
285 		len -= sizeof(struct virtio_net_hdr);
286 		skb_trim(skb, len);
287 	} else {
288 		page = buf;
289 		skb = page_to_skb(vi, page, len);
290 		if (unlikely(!skb)) {
291 			dev->stats.rx_dropped++;
292 			give_pages(vi, page);
293 			return;
294 		}
295 		if (vi->mergeable_rx_bufs)
296 			if (receive_mergeable(vi, skb)) {
297 				dev_kfree_skb(skb);
298 				return;
299 			}
300 	}
301 
302 	hdr = skb_vnet_hdr(skb);
303 
304 	u64_stats_update_begin(&stats->rx_syncp);
305 	stats->rx_bytes += skb->len;
306 	stats->rx_packets++;
307 	u64_stats_update_end(&stats->rx_syncp);
308 
309 	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
310 		pr_debug("Needs csum!\n");
311 		if (!skb_partial_csum_set(skb,
312 					  hdr->hdr.csum_start,
313 					  hdr->hdr.csum_offset))
314 			goto frame_err;
315 	} else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
316 		skb->ip_summed = CHECKSUM_UNNECESSARY;
317 	}
318 
319 	skb->protocol = eth_type_trans(skb, dev);
320 	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
321 		 ntohs(skb->protocol), skb->len, skb->pkt_type);
322 
323 	if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
324 		pr_debug("GSO!\n");
325 		switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
326 		case VIRTIO_NET_HDR_GSO_TCPV4:
327 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
328 			break;
329 		case VIRTIO_NET_HDR_GSO_UDP:
330 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
331 			break;
332 		case VIRTIO_NET_HDR_GSO_TCPV6:
333 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
334 			break;
335 		default:
336 			if (net_ratelimit())
337 				printk(KERN_WARNING "%s: bad gso type %u.\n",
338 				       dev->name, hdr->hdr.gso_type);
339 			goto frame_err;
340 		}
341 
342 		if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
343 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
344 
345 		skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
346 		if (skb_shinfo(skb)->gso_size == 0) {
347 			if (net_ratelimit())
348 				printk(KERN_WARNING "%s: zero gso size.\n",
349 				       dev->name);
350 			goto frame_err;
351 		}
352 
353 		/* Header must be checked, and gso_segs computed. */
354 		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
355 		skb_shinfo(skb)->gso_segs = 0;
356 	}
357 
358 	netif_receive_skb(skb);
359 	return;
360 
361 frame_err:
362 	dev->stats.rx_frame_errors++;
363 	dev_kfree_skb(skb);
364 }
365 
366 static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
367 {
368 	struct sk_buff *skb;
369 	struct skb_vnet_hdr *hdr;
370 	int err;
371 
372 	skb = __netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN, gfp);
373 	if (unlikely(!skb))
374 		return -ENOMEM;
375 
376 	skb_put(skb, MAX_PACKET_LEN);
377 
378 	hdr = skb_vnet_hdr(skb);
379 	sg_set_buf(vi->rx_sg, &hdr->hdr, sizeof hdr->hdr);
380 
381 	skb_to_sgvec(skb, vi->rx_sg + 1, 0, skb->len);
382 
383 	err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, 2, skb, gfp);
384 	if (err < 0)
385 		dev_kfree_skb(skb);
386 
387 	return err;
388 }
389 
390 static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
391 {
392 	struct page *first, *list = NULL;
393 	char *p;
394 	int i, err, offset;
395 
396 	/* page in vi->rx_sg[MAX_SKB_FRAGS + 1] is list tail */
397 	for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
398 		first = get_a_page(vi, gfp);
399 		if (!first) {
400 			if (list)
401 				give_pages(vi, list);
402 			return -ENOMEM;
403 		}
404 		sg_set_buf(&vi->rx_sg[i], page_address(first), PAGE_SIZE);
405 
406 		/* chain new page in list head to match sg */
407 		first->private = (unsigned long)list;
408 		list = first;
409 	}
410 
411 	first = get_a_page(vi, gfp);
412 	if (!first) {
413 		give_pages(vi, list);
414 		return -ENOMEM;
415 	}
416 	p = page_address(first);
417 
418 	/* vi->rx_sg[0], vi->rx_sg[1] share the same page */
419 	/* a separated vi->rx_sg[0] for virtio_net_hdr only due to QEMU bug */
420 	sg_set_buf(&vi->rx_sg[0], p, sizeof(struct virtio_net_hdr));
421 
422 	/* vi->rx_sg[1] for data packet, from offset */
423 	offset = sizeof(struct padded_vnet_hdr);
424 	sg_set_buf(&vi->rx_sg[1], p + offset, PAGE_SIZE - offset);
425 
426 	/* chain first in list head */
427 	first->private = (unsigned long)list;
428 	err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
429 				first, gfp);
430 	if (err < 0)
431 		give_pages(vi, first);
432 
433 	return err;
434 }
435 
436 static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
437 {
438 	struct page *page;
439 	int err;
440 
441 	page = get_a_page(vi, gfp);
442 	if (!page)
443 		return -ENOMEM;
444 
445 	sg_init_one(vi->rx_sg, page_address(page), PAGE_SIZE);
446 
447 	err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, 1, page, gfp);
448 	if (err < 0)
449 		give_pages(vi, page);
450 
451 	return err;
452 }
453 
454 /*
455  * Returns false if we couldn't fill entirely (OOM).
456  *
457  * Normally run in the receive path, but can also be run from ndo_open
458  * before we're receiving packets, or from refill_work which is
459  * careful to disable receiving (using napi_disable).
460  */
461 static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
462 {
463 	int err;
464 	bool oom;
465 
466 	do {
467 		if (vi->mergeable_rx_bufs)
468 			err = add_recvbuf_mergeable(vi, gfp);
469 		else if (vi->big_packets)
470 			err = add_recvbuf_big(vi, gfp);
471 		else
472 			err = add_recvbuf_small(vi, gfp);
473 
474 		oom = err == -ENOMEM;
475 		if (err < 0)
476 			break;
477 		++vi->num;
478 	} while (err > 0);
479 	if (unlikely(vi->num > vi->max))
480 		vi->max = vi->num;
481 	virtqueue_kick(vi->rvq);
482 	return !oom;
483 }
484 
485 static void skb_recv_done(struct virtqueue *rvq)
486 {
487 	struct virtnet_info *vi = rvq->vdev->priv;
488 	/* Schedule NAPI, Suppress further interrupts if successful. */
489 	if (napi_schedule_prep(&vi->napi)) {
490 		virtqueue_disable_cb(rvq);
491 		__napi_schedule(&vi->napi);
492 	}
493 }
494 
495 static void virtnet_napi_enable(struct virtnet_info *vi)
496 {
497 	napi_enable(&vi->napi);
498 
499 	/* If all buffers were filled by other side before we napi_enabled, we
500 	 * won't get another interrupt, so process any outstanding packets
501 	 * now.  virtnet_poll wants re-enable the queue, so we disable here.
502 	 * We synchronize against interrupts via NAPI_STATE_SCHED */
503 	if (napi_schedule_prep(&vi->napi)) {
504 		virtqueue_disable_cb(vi->rvq);
505 		local_bh_disable();
506 		__napi_schedule(&vi->napi);
507 		local_bh_enable();
508 	}
509 }
510 
511 static void refill_work(struct work_struct *work)
512 {
513 	struct virtnet_info *vi;
514 	bool still_empty;
515 
516 	vi = container_of(work, struct virtnet_info, refill.work);
517 	napi_disable(&vi->napi);
518 	still_empty = !try_fill_recv(vi, GFP_KERNEL);
519 	virtnet_napi_enable(vi);
520 
521 	/* In theory, this can happen: if we don't get any buffers in
522 	 * we will *never* try to fill again. */
523 	if (still_empty)
524 		queue_delayed_work(system_nrt_wq, &vi->refill, HZ/2);
525 }
526 
527 static int virtnet_poll(struct napi_struct *napi, int budget)
528 {
529 	struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
530 	void *buf;
531 	unsigned int len, received = 0;
532 
533 again:
534 	while (received < budget &&
535 	       (buf = virtqueue_get_buf(vi->rvq, &len)) != NULL) {
536 		receive_buf(vi->dev, buf, len);
537 		--vi->num;
538 		received++;
539 	}
540 
541 	if (vi->num < vi->max / 2) {
542 		if (!try_fill_recv(vi, GFP_ATOMIC))
543 			queue_delayed_work(system_nrt_wq, &vi->refill, 0);
544 	}
545 
546 	/* Out of packets? */
547 	if (received < budget) {
548 		napi_complete(napi);
549 		if (unlikely(!virtqueue_enable_cb(vi->rvq)) &&
550 		    napi_schedule_prep(napi)) {
551 			virtqueue_disable_cb(vi->rvq);
552 			__napi_schedule(napi);
553 			goto again;
554 		}
555 	}
556 
557 	return received;
558 }
559 
560 static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
561 {
562 	struct sk_buff *skb;
563 	unsigned int len, tot_sgs = 0;
564 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
565 
566 	while ((skb = virtqueue_get_buf(vi->svq, &len)) != NULL) {
567 		pr_debug("Sent skb %p\n", skb);
568 
569 		u64_stats_update_begin(&stats->tx_syncp);
570 		stats->tx_bytes += skb->len;
571 		stats->tx_packets++;
572 		u64_stats_update_end(&stats->tx_syncp);
573 
574 		tot_sgs += skb_vnet_hdr(skb)->num_sg;
575 		dev_kfree_skb_any(skb);
576 	}
577 	return tot_sgs;
578 }
579 
580 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
581 {
582 	struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
583 	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
584 
585 	pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
586 
587 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
588 		hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
589 		hdr->hdr.csum_start = skb_checksum_start_offset(skb);
590 		hdr->hdr.csum_offset = skb->csum_offset;
591 	} else {
592 		hdr->hdr.flags = 0;
593 		hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
594 	}
595 
596 	if (skb_is_gso(skb)) {
597 		hdr->hdr.hdr_len = skb_headlen(skb);
598 		hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
599 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
600 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
601 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
602 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
603 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
604 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
605 		else
606 			BUG();
607 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
608 			hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
609 	} else {
610 		hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
611 		hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
612 	}
613 
614 	hdr->mhdr.num_buffers = 0;
615 
616 	/* Encode metadata header at front. */
617 	if (vi->mergeable_rx_bufs)
618 		sg_set_buf(vi->tx_sg, &hdr->mhdr, sizeof hdr->mhdr);
619 	else
620 		sg_set_buf(vi->tx_sg, &hdr->hdr, sizeof hdr->hdr);
621 
622 	hdr->num_sg = skb_to_sgvec(skb, vi->tx_sg + 1, 0, skb->len) + 1;
623 	return virtqueue_add_buf(vi->svq, vi->tx_sg, hdr->num_sg,
624 				 0, skb, GFP_ATOMIC);
625 }
626 
627 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
628 {
629 	struct virtnet_info *vi = netdev_priv(dev);
630 	int capacity;
631 
632 	/* Free up any pending old buffers before queueing new ones. */
633 	free_old_xmit_skbs(vi);
634 
635 	/* Try to transmit */
636 	capacity = xmit_skb(vi, skb);
637 
638 	/* This can happen with OOM and indirect buffers. */
639 	if (unlikely(capacity < 0)) {
640 		if (likely(capacity == -ENOMEM)) {
641 			if (net_ratelimit())
642 				dev_warn(&dev->dev,
643 					 "TX queue failure: out of memory\n");
644 		} else {
645 			dev->stats.tx_fifo_errors++;
646 			if (net_ratelimit())
647 				dev_warn(&dev->dev,
648 					 "Unexpected TX queue failure: %d\n",
649 					 capacity);
650 		}
651 		dev->stats.tx_dropped++;
652 		kfree_skb(skb);
653 		return NETDEV_TX_OK;
654 	}
655 	virtqueue_kick(vi->svq);
656 
657 	/* Don't wait up for transmitted skbs to be freed. */
658 	skb_orphan(skb);
659 	nf_reset(skb);
660 
661 	/* Apparently nice girls don't return TX_BUSY; stop the queue
662 	 * before it gets out of hand.  Naturally, this wastes entries. */
663 	if (capacity < 2+MAX_SKB_FRAGS) {
664 		netif_stop_queue(dev);
665 		if (unlikely(!virtqueue_enable_cb_delayed(vi->svq))) {
666 			/* More just got used, free them then recheck. */
667 			capacity += free_old_xmit_skbs(vi);
668 			if (capacity >= 2+MAX_SKB_FRAGS) {
669 				netif_start_queue(dev);
670 				virtqueue_disable_cb(vi->svq);
671 			}
672 		}
673 	}
674 
675 	return NETDEV_TX_OK;
676 }
677 
678 static int virtnet_set_mac_address(struct net_device *dev, void *p)
679 {
680 	struct virtnet_info *vi = netdev_priv(dev);
681 	struct virtio_device *vdev = vi->vdev;
682 	int ret;
683 
684 	ret = eth_mac_addr(dev, p);
685 	if (ret)
686 		return ret;
687 
688 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
689 		vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
690 		                  dev->dev_addr, dev->addr_len);
691 
692 	return 0;
693 }
694 
695 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
696 					       struct rtnl_link_stats64 *tot)
697 {
698 	struct virtnet_info *vi = netdev_priv(dev);
699 	int cpu;
700 	unsigned int start;
701 
702 	for_each_possible_cpu(cpu) {
703 		struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
704 		u64 tpackets, tbytes, rpackets, rbytes;
705 
706 		do {
707 			start = u64_stats_fetch_begin_bh(&stats->tx_syncp);
708 			tpackets = stats->tx_packets;
709 			tbytes   = stats->tx_bytes;
710 		} while (u64_stats_fetch_retry_bh(&stats->tx_syncp, start));
711 
712 		do {
713 			start = u64_stats_fetch_begin_bh(&stats->rx_syncp);
714 			rpackets = stats->rx_packets;
715 			rbytes   = stats->rx_bytes;
716 		} while (u64_stats_fetch_retry_bh(&stats->rx_syncp, start));
717 
718 		tot->rx_packets += rpackets;
719 		tot->tx_packets += tpackets;
720 		tot->rx_bytes   += rbytes;
721 		tot->tx_bytes   += tbytes;
722 	}
723 
724 	tot->tx_dropped = dev->stats.tx_dropped;
725 	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
726 	tot->rx_dropped = dev->stats.rx_dropped;
727 	tot->rx_length_errors = dev->stats.rx_length_errors;
728 	tot->rx_frame_errors = dev->stats.rx_frame_errors;
729 
730 	return tot;
731 }
732 
733 #ifdef CONFIG_NET_POLL_CONTROLLER
734 static void virtnet_netpoll(struct net_device *dev)
735 {
736 	struct virtnet_info *vi = netdev_priv(dev);
737 
738 	napi_schedule(&vi->napi);
739 }
740 #endif
741 
742 static int virtnet_open(struct net_device *dev)
743 {
744 	struct virtnet_info *vi = netdev_priv(dev);
745 
746 	/* Make sure we have some buffers: if oom use wq. */
747 	if (!try_fill_recv(vi, GFP_KERNEL))
748 		queue_delayed_work(system_nrt_wq, &vi->refill, 0);
749 
750 	virtnet_napi_enable(vi);
751 	return 0;
752 }
753 
754 /*
755  * Send command via the control virtqueue and check status.  Commands
756  * supported by the hypervisor, as indicated by feature bits, should
757  * never fail unless improperly formated.
758  */
759 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
760 				 struct scatterlist *data, int out, int in)
761 {
762 	struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
763 	struct virtio_net_ctrl_hdr ctrl;
764 	virtio_net_ctrl_ack status = ~0;
765 	unsigned int tmp;
766 	int i;
767 
768 	/* Caller should know better */
769 	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
770 		(out + in > VIRTNET_SEND_COMMAND_SG_MAX));
771 
772 	out++; /* Add header */
773 	in++; /* Add return status */
774 
775 	ctrl.class = class;
776 	ctrl.cmd = cmd;
777 
778 	sg_init_table(sg, out + in);
779 
780 	sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
781 	for_each_sg(data, s, out + in - 2, i)
782 		sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
783 	sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
784 
785 	BUG_ON(virtqueue_add_buf(vi->cvq, sg, out, in, vi, GFP_ATOMIC) < 0);
786 
787 	virtqueue_kick(vi->cvq);
788 
789 	/*
790 	 * Spin for a response, the kick causes an ioport write, trapping
791 	 * into the hypervisor, so the request should be handled immediately.
792 	 */
793 	while (!virtqueue_get_buf(vi->cvq, &tmp))
794 		cpu_relax();
795 
796 	return status == VIRTIO_NET_OK;
797 }
798 
799 static void virtnet_ack_link_announce(struct virtnet_info *vi)
800 {
801 	rtnl_lock();
802 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
803 				  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL,
804 				  0, 0))
805 		dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
806 	rtnl_unlock();
807 }
808 
809 static int virtnet_close(struct net_device *dev)
810 {
811 	struct virtnet_info *vi = netdev_priv(dev);
812 
813 	/* Make sure refill_work doesn't re-enable napi! */
814 	cancel_delayed_work_sync(&vi->refill);
815 	napi_disable(&vi->napi);
816 
817 	return 0;
818 }
819 
820 static void virtnet_set_rx_mode(struct net_device *dev)
821 {
822 	struct virtnet_info *vi = netdev_priv(dev);
823 	struct scatterlist sg[2];
824 	u8 promisc, allmulti;
825 	struct virtio_net_ctrl_mac *mac_data;
826 	struct netdev_hw_addr *ha;
827 	int uc_count;
828 	int mc_count;
829 	void *buf;
830 	int i;
831 
832 	/* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
833 	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
834 		return;
835 
836 	promisc = ((dev->flags & IFF_PROMISC) != 0);
837 	allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
838 
839 	sg_init_one(sg, &promisc, sizeof(promisc));
840 
841 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
842 				  VIRTIO_NET_CTRL_RX_PROMISC,
843 				  sg, 1, 0))
844 		dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
845 			 promisc ? "en" : "dis");
846 
847 	sg_init_one(sg, &allmulti, sizeof(allmulti));
848 
849 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
850 				  VIRTIO_NET_CTRL_RX_ALLMULTI,
851 				  sg, 1, 0))
852 		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
853 			 allmulti ? "en" : "dis");
854 
855 	uc_count = netdev_uc_count(dev);
856 	mc_count = netdev_mc_count(dev);
857 	/* MAC filter - use one buffer for both lists */
858 	buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
859 		      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
860 	mac_data = buf;
861 	if (!buf) {
862 		dev_warn(&dev->dev, "No memory for MAC address buffer\n");
863 		return;
864 	}
865 
866 	sg_init_table(sg, 2);
867 
868 	/* Store the unicast list and count in the front of the buffer */
869 	mac_data->entries = uc_count;
870 	i = 0;
871 	netdev_for_each_uc_addr(ha, dev)
872 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
873 
874 	sg_set_buf(&sg[0], mac_data,
875 		   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
876 
877 	/* multicast list and count fill the end */
878 	mac_data = (void *)&mac_data->macs[uc_count][0];
879 
880 	mac_data->entries = mc_count;
881 	i = 0;
882 	netdev_for_each_mc_addr(ha, dev)
883 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
884 
885 	sg_set_buf(&sg[1], mac_data,
886 		   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
887 
888 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
889 				  VIRTIO_NET_CTRL_MAC_TABLE_SET,
890 				  sg, 2, 0))
891 		dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
892 
893 	kfree(buf);
894 }
895 
896 static int virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
897 {
898 	struct virtnet_info *vi = netdev_priv(dev);
899 	struct scatterlist sg;
900 
901 	sg_init_one(&sg, &vid, sizeof(vid));
902 
903 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
904 				  VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
905 		dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
906 	return 0;
907 }
908 
909 static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
910 {
911 	struct virtnet_info *vi = netdev_priv(dev);
912 	struct scatterlist sg;
913 
914 	sg_init_one(&sg, &vid, sizeof(vid));
915 
916 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
917 				  VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
918 		dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
919 	return 0;
920 }
921 
922 static void virtnet_get_ringparam(struct net_device *dev,
923 				struct ethtool_ringparam *ring)
924 {
925 	struct virtnet_info *vi = netdev_priv(dev);
926 
927 	ring->rx_max_pending = virtqueue_get_vring_size(vi->rvq);
928 	ring->tx_max_pending = virtqueue_get_vring_size(vi->svq);
929 	ring->rx_pending = ring->rx_max_pending;
930 	ring->tx_pending = ring->tx_max_pending;
931 
932 }
933 
934 
935 static void virtnet_get_drvinfo(struct net_device *dev,
936 				struct ethtool_drvinfo *info)
937 {
938 	struct virtnet_info *vi = netdev_priv(dev);
939 	struct virtio_device *vdev = vi->vdev;
940 
941 	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
942 	strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
943 	strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
944 
945 }
946 
947 static const struct ethtool_ops virtnet_ethtool_ops = {
948 	.get_drvinfo = virtnet_get_drvinfo,
949 	.get_link = ethtool_op_get_link,
950 	.get_ringparam = virtnet_get_ringparam,
951 };
952 
953 #define MIN_MTU 68
954 #define MAX_MTU 65535
955 
956 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
957 {
958 	if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
959 		return -EINVAL;
960 	dev->mtu = new_mtu;
961 	return 0;
962 }
963 
964 static const struct net_device_ops virtnet_netdev = {
965 	.ndo_open            = virtnet_open,
966 	.ndo_stop   	     = virtnet_close,
967 	.ndo_start_xmit      = start_xmit,
968 	.ndo_validate_addr   = eth_validate_addr,
969 	.ndo_set_mac_address = virtnet_set_mac_address,
970 	.ndo_set_rx_mode     = virtnet_set_rx_mode,
971 	.ndo_change_mtu	     = virtnet_change_mtu,
972 	.ndo_get_stats64     = virtnet_stats,
973 	.ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
974 	.ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
975 #ifdef CONFIG_NET_POLL_CONTROLLER
976 	.ndo_poll_controller = virtnet_netpoll,
977 #endif
978 };
979 
980 static void virtnet_config_changed_work(struct work_struct *work)
981 {
982 	struct virtnet_info *vi =
983 		container_of(work, struct virtnet_info, config_work);
984 	u16 v;
985 
986 	mutex_lock(&vi->config_lock);
987 	if (!vi->config_enable)
988 		goto done;
989 
990 	if (virtio_config_val(vi->vdev, VIRTIO_NET_F_STATUS,
991 			      offsetof(struct virtio_net_config, status),
992 			      &v) < 0)
993 		goto done;
994 
995 	if (v & VIRTIO_NET_S_ANNOUNCE) {
996 		netif_notify_peers(vi->dev);
997 		virtnet_ack_link_announce(vi);
998 	}
999 
1000 	/* Ignore unknown (future) status bits */
1001 	v &= VIRTIO_NET_S_LINK_UP;
1002 
1003 	if (vi->status == v)
1004 		goto done;
1005 
1006 	vi->status = v;
1007 
1008 	if (vi->status & VIRTIO_NET_S_LINK_UP) {
1009 		netif_carrier_on(vi->dev);
1010 		netif_wake_queue(vi->dev);
1011 	} else {
1012 		netif_carrier_off(vi->dev);
1013 		netif_stop_queue(vi->dev);
1014 	}
1015 done:
1016 	mutex_unlock(&vi->config_lock);
1017 }
1018 
1019 static void virtnet_config_changed(struct virtio_device *vdev)
1020 {
1021 	struct virtnet_info *vi = vdev->priv;
1022 
1023 	queue_work(system_nrt_wq, &vi->config_work);
1024 }
1025 
1026 static int init_vqs(struct virtnet_info *vi)
1027 {
1028 	struct virtqueue *vqs[3];
1029 	vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
1030 	const char *names[] = { "input", "output", "control" };
1031 	int nvqs, err;
1032 
1033 	/* We expect two virtqueues, receive then send,
1034 	 * and optionally control. */
1035 	nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
1036 
1037 	err = vi->vdev->config->find_vqs(vi->vdev, nvqs, vqs, callbacks, names);
1038 	if (err)
1039 		return err;
1040 
1041 	vi->rvq = vqs[0];
1042 	vi->svq = vqs[1];
1043 
1044 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
1045 		vi->cvq = vqs[2];
1046 
1047 		if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1048 			vi->dev->features |= NETIF_F_HW_VLAN_FILTER;
1049 	}
1050 	return 0;
1051 }
1052 
1053 static int virtnet_probe(struct virtio_device *vdev)
1054 {
1055 	int err;
1056 	struct net_device *dev;
1057 	struct virtnet_info *vi;
1058 
1059 	/* Allocate ourselves a network device with room for our info */
1060 	dev = alloc_etherdev(sizeof(struct virtnet_info));
1061 	if (!dev)
1062 		return -ENOMEM;
1063 
1064 	/* Set up network device as normal. */
1065 	dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1066 	dev->netdev_ops = &virtnet_netdev;
1067 	dev->features = NETIF_F_HIGHDMA;
1068 
1069 	SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
1070 	SET_NETDEV_DEV(dev, &vdev->dev);
1071 
1072 	/* Do we support "hardware" checksums? */
1073 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1074 		/* This opens up the world of extra features. */
1075 		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1076 		if (csum)
1077 			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1078 
1079 		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1080 			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1081 				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
1082 		}
1083 		/* Individual feature bits: what can host handle? */
1084 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1085 			dev->hw_features |= NETIF_F_TSO;
1086 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1087 			dev->hw_features |= NETIF_F_TSO6;
1088 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1089 			dev->hw_features |= NETIF_F_TSO_ECN;
1090 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1091 			dev->hw_features |= NETIF_F_UFO;
1092 
1093 		if (gso)
1094 			dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1095 		/* (!csum && gso) case will be fixed by register_netdev() */
1096 	}
1097 
1098 	/* Configuration may specify what MAC to use.  Otherwise random. */
1099 	if (virtio_config_val_len(vdev, VIRTIO_NET_F_MAC,
1100 				  offsetof(struct virtio_net_config, mac),
1101 				  dev->dev_addr, dev->addr_len) < 0)
1102 		eth_hw_addr_random(dev);
1103 
1104 	/* Set up our device-specific information */
1105 	vi = netdev_priv(dev);
1106 	netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
1107 	vi->dev = dev;
1108 	vi->vdev = vdev;
1109 	vdev->priv = vi;
1110 	vi->pages = NULL;
1111 	vi->stats = alloc_percpu(struct virtnet_stats);
1112 	err = -ENOMEM;
1113 	if (vi->stats == NULL)
1114 		goto free;
1115 
1116 	INIT_DELAYED_WORK(&vi->refill, refill_work);
1117 	mutex_init(&vi->config_lock);
1118 	vi->config_enable = true;
1119 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1120 	sg_init_table(vi->rx_sg, ARRAY_SIZE(vi->rx_sg));
1121 	sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg));
1122 
1123 	/* If we can receive ANY GSO packets, we must allocate large ones. */
1124 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1125 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1126 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
1127 		vi->big_packets = true;
1128 
1129 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1130 		vi->mergeable_rx_bufs = true;
1131 
1132 	err = init_vqs(vi);
1133 	if (err)
1134 		goto free_stats;
1135 
1136 	err = register_netdev(dev);
1137 	if (err) {
1138 		pr_debug("virtio_net: registering device failed\n");
1139 		goto free_vqs;
1140 	}
1141 
1142 	/* Last of all, set up some receive buffers. */
1143 	try_fill_recv(vi, GFP_KERNEL);
1144 
1145 	/* If we didn't even get one input buffer, we're useless. */
1146 	if (vi->num == 0) {
1147 		err = -ENOMEM;
1148 		goto unregister;
1149 	}
1150 
1151 	/* Assume link up if device can't report link status,
1152 	   otherwise get link status from config. */
1153 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1154 		netif_carrier_off(dev);
1155 		queue_work(system_nrt_wq, &vi->config_work);
1156 	} else {
1157 		vi->status = VIRTIO_NET_S_LINK_UP;
1158 		netif_carrier_on(dev);
1159 	}
1160 
1161 	pr_debug("virtnet: registered device %s\n", dev->name);
1162 	return 0;
1163 
1164 unregister:
1165 	unregister_netdev(dev);
1166 free_vqs:
1167 	vdev->config->del_vqs(vdev);
1168 free_stats:
1169 	free_percpu(vi->stats);
1170 free:
1171 	free_netdev(dev);
1172 	return err;
1173 }
1174 
1175 static void free_unused_bufs(struct virtnet_info *vi)
1176 {
1177 	void *buf;
1178 	while (1) {
1179 		buf = virtqueue_detach_unused_buf(vi->svq);
1180 		if (!buf)
1181 			break;
1182 		dev_kfree_skb(buf);
1183 	}
1184 	while (1) {
1185 		buf = virtqueue_detach_unused_buf(vi->rvq);
1186 		if (!buf)
1187 			break;
1188 		if (vi->mergeable_rx_bufs || vi->big_packets)
1189 			give_pages(vi, buf);
1190 		else
1191 			dev_kfree_skb(buf);
1192 		--vi->num;
1193 	}
1194 	BUG_ON(vi->num != 0);
1195 }
1196 
1197 static void remove_vq_common(struct virtnet_info *vi)
1198 {
1199 	vi->vdev->config->reset(vi->vdev);
1200 
1201 	/* Free unused buffers in both send and recv, if any. */
1202 	free_unused_bufs(vi);
1203 
1204 	vi->vdev->config->del_vqs(vi->vdev);
1205 
1206 	while (vi->pages)
1207 		__free_pages(get_a_page(vi, GFP_KERNEL), 0);
1208 }
1209 
1210 static void __devexit virtnet_remove(struct virtio_device *vdev)
1211 {
1212 	struct virtnet_info *vi = vdev->priv;
1213 
1214 	/* Prevent config work handler from accessing the device. */
1215 	mutex_lock(&vi->config_lock);
1216 	vi->config_enable = false;
1217 	mutex_unlock(&vi->config_lock);
1218 
1219 	unregister_netdev(vi->dev);
1220 
1221 	remove_vq_common(vi);
1222 
1223 	flush_work(&vi->config_work);
1224 
1225 	free_percpu(vi->stats);
1226 	free_netdev(vi->dev);
1227 }
1228 
1229 #ifdef CONFIG_PM
1230 static int virtnet_freeze(struct virtio_device *vdev)
1231 {
1232 	struct virtnet_info *vi = vdev->priv;
1233 
1234 	/* Prevent config work handler from accessing the device */
1235 	mutex_lock(&vi->config_lock);
1236 	vi->config_enable = false;
1237 	mutex_unlock(&vi->config_lock);
1238 
1239 	netif_device_detach(vi->dev);
1240 	cancel_delayed_work_sync(&vi->refill);
1241 
1242 	if (netif_running(vi->dev))
1243 		napi_disable(&vi->napi);
1244 
1245 	remove_vq_common(vi);
1246 
1247 	flush_work(&vi->config_work);
1248 
1249 	return 0;
1250 }
1251 
1252 static int virtnet_restore(struct virtio_device *vdev)
1253 {
1254 	struct virtnet_info *vi = vdev->priv;
1255 	int err;
1256 
1257 	err = init_vqs(vi);
1258 	if (err)
1259 		return err;
1260 
1261 	if (netif_running(vi->dev))
1262 		virtnet_napi_enable(vi);
1263 
1264 	netif_device_attach(vi->dev);
1265 
1266 	if (!try_fill_recv(vi, GFP_KERNEL))
1267 		queue_delayed_work(system_nrt_wq, &vi->refill, 0);
1268 
1269 	mutex_lock(&vi->config_lock);
1270 	vi->config_enable = true;
1271 	mutex_unlock(&vi->config_lock);
1272 
1273 	return 0;
1274 }
1275 #endif
1276 
1277 static struct virtio_device_id id_table[] = {
1278 	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1279 	{ 0 },
1280 };
1281 
1282 static unsigned int features[] = {
1283 	VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1284 	VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1285 	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1286 	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1287 	VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1288 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1289 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1290 	VIRTIO_NET_F_GUEST_ANNOUNCE,
1291 };
1292 
1293 static struct virtio_driver virtio_net_driver = {
1294 	.feature_table = features,
1295 	.feature_table_size = ARRAY_SIZE(features),
1296 	.driver.name =	KBUILD_MODNAME,
1297 	.driver.owner =	THIS_MODULE,
1298 	.id_table =	id_table,
1299 	.probe =	virtnet_probe,
1300 	.remove =	__devexit_p(virtnet_remove),
1301 	.config_changed = virtnet_config_changed,
1302 #ifdef CONFIG_PM
1303 	.freeze =	virtnet_freeze,
1304 	.restore =	virtnet_restore,
1305 #endif
1306 };
1307 
1308 static int __init init(void)
1309 {
1310 	return register_virtio_driver(&virtio_net_driver);
1311 }
1312 
1313 static void __exit fini(void)
1314 {
1315 	unregister_virtio_driver(&virtio_net_driver);
1316 }
1317 module_init(init);
1318 module_exit(fini);
1319 
1320 MODULE_DEVICE_TABLE(virtio, id_table);
1321 MODULE_DESCRIPTION("Virtio network driver");
1322 MODULE_LICENSE("GPL");
1323