xref: /openbmc/linux/drivers/net/virtio_net.c (revision 827634ad)
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, see <http://www.gnu.org/licenses/>.
17  */
18 //#define DEBUG
19 #include <linux/netdevice.h>
20 #include <linux/etherdevice.h>
21 #include <linux/ethtool.h>
22 #include <linux/module.h>
23 #include <linux/virtio.h>
24 #include <linux/virtio_net.h>
25 #include <linux/scatterlist.h>
26 #include <linux/if_vlan.h>
27 #include <linux/slab.h>
28 #include <linux/cpu.h>
29 #include <linux/average.h>
30 #include <net/busy_poll.h>
31 
32 static int napi_weight = NAPI_POLL_WEIGHT;
33 module_param(napi_weight, int, 0444);
34 
35 static bool csum = true, gso = true;
36 module_param(csum, bool, 0444);
37 module_param(gso, bool, 0444);
38 
39 /* FIXME: MTU in config. */
40 #define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
41 #define GOOD_COPY_LEN	128
42 
43 /* Weight used for the RX packet size EWMA. The average packet size is used to
44  * determine the packet buffer size when refilling RX rings. As the entire RX
45  * ring may be refilled at once, the weight is chosen so that the EWMA will be
46  * insensitive to short-term, transient changes in packet size.
47  */
48 #define RECEIVE_AVG_WEIGHT 64
49 
50 /* Minimum alignment for mergeable packet buffers. */
51 #define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, 256)
52 
53 #define VIRTNET_DRIVER_VERSION "1.0.0"
54 
55 struct virtnet_stats {
56 	struct u64_stats_sync tx_syncp;
57 	struct u64_stats_sync rx_syncp;
58 	u64 tx_bytes;
59 	u64 tx_packets;
60 
61 	u64 rx_bytes;
62 	u64 rx_packets;
63 };
64 
65 /* Internal representation of a send virtqueue */
66 struct send_queue {
67 	/* Virtqueue associated with this send _queue */
68 	struct virtqueue *vq;
69 
70 	/* TX: fragments + linear part + virtio header */
71 	struct scatterlist sg[MAX_SKB_FRAGS + 2];
72 
73 	/* Name of the send queue: output.$index */
74 	char name[40];
75 };
76 
77 /* Internal representation of a receive virtqueue */
78 struct receive_queue {
79 	/* Virtqueue associated with this receive_queue */
80 	struct virtqueue *vq;
81 
82 	struct napi_struct napi;
83 
84 	/* Chain pages by the private ptr. */
85 	struct page *pages;
86 
87 	/* Average packet length for mergeable receive buffers. */
88 	struct ewma mrg_avg_pkt_len;
89 
90 	/* Page frag for packet buffer allocation. */
91 	struct page_frag alloc_frag;
92 
93 	/* RX: fragments + linear part + virtio header */
94 	struct scatterlist sg[MAX_SKB_FRAGS + 2];
95 
96 	/* Name of this receive queue: input.$index */
97 	char name[40];
98 };
99 
100 struct virtnet_info {
101 	struct virtio_device *vdev;
102 	struct virtqueue *cvq;
103 	struct net_device *dev;
104 	struct send_queue *sq;
105 	struct receive_queue *rq;
106 	unsigned int status;
107 
108 	/* Max # of queue pairs supported by the device */
109 	u16 max_queue_pairs;
110 
111 	/* # of queue pairs currently used by the driver */
112 	u16 curr_queue_pairs;
113 
114 	/* I like... big packets and I cannot lie! */
115 	bool big_packets;
116 
117 	/* Host will merge rx buffers for big packets (shake it! shake it!) */
118 	bool mergeable_rx_bufs;
119 
120 	/* Has control virtqueue */
121 	bool has_cvq;
122 
123 	/* Host can handle any s/g split between our header and packet data */
124 	bool any_header_sg;
125 
126 	/* Packet virtio header size */
127 	u8 hdr_len;
128 
129 	/* Active statistics */
130 	struct virtnet_stats __percpu *stats;
131 
132 	/* Work struct for refilling if we run low on memory. */
133 	struct delayed_work refill;
134 
135 	/* Work struct for config space updates */
136 	struct work_struct config_work;
137 
138 	/* Does the affinity hint is set for virtqueues? */
139 	bool affinity_hint_set;
140 
141 	/* CPU hot plug notifier */
142 	struct notifier_block nb;
143 };
144 
145 struct padded_vnet_hdr {
146 	struct virtio_net_hdr_mrg_rxbuf hdr;
147 	/*
148 	 * hdr is in a separate sg buffer, and data sg buffer shares same page
149 	 * with this header sg. This padding makes next sg 16 byte aligned
150 	 * after the header.
151 	 */
152 	char padding[4];
153 };
154 
155 /* Converting between virtqueue no. and kernel tx/rx queue no.
156  * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
157  */
158 static int vq2txq(struct virtqueue *vq)
159 {
160 	return (vq->index - 1) / 2;
161 }
162 
163 static int txq2vq(int txq)
164 {
165 	return txq * 2 + 1;
166 }
167 
168 static int vq2rxq(struct virtqueue *vq)
169 {
170 	return vq->index / 2;
171 }
172 
173 static int rxq2vq(int rxq)
174 {
175 	return rxq * 2;
176 }
177 
178 static inline struct virtio_net_hdr_mrg_rxbuf *skb_vnet_hdr(struct sk_buff *skb)
179 {
180 	return (struct virtio_net_hdr_mrg_rxbuf *)skb->cb;
181 }
182 
183 /*
184  * private is used to chain pages for big packets, put the whole
185  * most recent used list in the beginning for reuse
186  */
187 static void give_pages(struct receive_queue *rq, struct page *page)
188 {
189 	struct page *end;
190 
191 	/* Find end of list, sew whole thing into vi->rq.pages. */
192 	for (end = page; end->private; end = (struct page *)end->private);
193 	end->private = (unsigned long)rq->pages;
194 	rq->pages = page;
195 }
196 
197 static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
198 {
199 	struct page *p = rq->pages;
200 
201 	if (p) {
202 		rq->pages = (struct page *)p->private;
203 		/* clear private here, it is used to chain pages */
204 		p->private = 0;
205 	} else
206 		p = alloc_page(gfp_mask);
207 	return p;
208 }
209 
210 static void skb_xmit_done(struct virtqueue *vq)
211 {
212 	struct virtnet_info *vi = vq->vdev->priv;
213 
214 	/* Suppress further interrupts. */
215 	virtqueue_disable_cb(vq);
216 
217 	/* We were probably waiting for more output buffers. */
218 	netif_wake_subqueue(vi->dev, vq2txq(vq));
219 }
220 
221 static unsigned int mergeable_ctx_to_buf_truesize(unsigned long mrg_ctx)
222 {
223 	unsigned int truesize = mrg_ctx & (MERGEABLE_BUFFER_ALIGN - 1);
224 	return (truesize + 1) * MERGEABLE_BUFFER_ALIGN;
225 }
226 
227 static void *mergeable_ctx_to_buf_address(unsigned long mrg_ctx)
228 {
229 	return (void *)(mrg_ctx & -MERGEABLE_BUFFER_ALIGN);
230 
231 }
232 
233 static unsigned long mergeable_buf_to_ctx(void *buf, unsigned int truesize)
234 {
235 	unsigned int size = truesize / MERGEABLE_BUFFER_ALIGN;
236 	return (unsigned long)buf | (size - 1);
237 }
238 
239 /* Called from bottom half context */
240 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
241 				   struct receive_queue *rq,
242 				   struct page *page, unsigned int offset,
243 				   unsigned int len, unsigned int truesize)
244 {
245 	struct sk_buff *skb;
246 	struct virtio_net_hdr_mrg_rxbuf *hdr;
247 	unsigned int copy, hdr_len, hdr_padded_len;
248 	char *p;
249 
250 	p = page_address(page) + offset;
251 
252 	/* copy small packet so we can reuse these pages for small data */
253 	skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
254 	if (unlikely(!skb))
255 		return NULL;
256 
257 	hdr = skb_vnet_hdr(skb);
258 
259 	hdr_len = vi->hdr_len;
260 	if (vi->mergeable_rx_bufs)
261 		hdr_padded_len = sizeof *hdr;
262 	else
263 		hdr_padded_len = sizeof(struct padded_vnet_hdr);
264 
265 	memcpy(hdr, p, hdr_len);
266 
267 	len -= hdr_len;
268 	offset += hdr_padded_len;
269 	p += hdr_padded_len;
270 
271 	copy = len;
272 	if (copy > skb_tailroom(skb))
273 		copy = skb_tailroom(skb);
274 	memcpy(skb_put(skb, copy), p, copy);
275 
276 	len -= copy;
277 	offset += copy;
278 
279 	if (vi->mergeable_rx_bufs) {
280 		if (len)
281 			skb_add_rx_frag(skb, 0, page, offset, len, truesize);
282 		else
283 			put_page(page);
284 		return skb;
285 	}
286 
287 	/*
288 	 * Verify that we can indeed put this data into a skb.
289 	 * This is here to handle cases when the device erroneously
290 	 * tries to receive more than is possible. This is usually
291 	 * the case of a broken device.
292 	 */
293 	if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
294 		net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
295 		dev_kfree_skb(skb);
296 		return NULL;
297 	}
298 	BUG_ON(offset >= PAGE_SIZE);
299 	while (len) {
300 		unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
301 		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
302 				frag_size, truesize);
303 		len -= frag_size;
304 		page = (struct page *)page->private;
305 		offset = 0;
306 	}
307 
308 	if (page)
309 		give_pages(rq, page);
310 
311 	return skb;
312 }
313 
314 static struct sk_buff *receive_small(struct virtnet_info *vi, void *buf, unsigned int len)
315 {
316 	struct sk_buff * skb = buf;
317 
318 	len -= vi->hdr_len;
319 	skb_trim(skb, len);
320 
321 	return skb;
322 }
323 
324 static struct sk_buff *receive_big(struct net_device *dev,
325 				   struct virtnet_info *vi,
326 				   struct receive_queue *rq,
327 				   void *buf,
328 				   unsigned int len)
329 {
330 	struct page *page = buf;
331 	struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
332 
333 	if (unlikely(!skb))
334 		goto err;
335 
336 	return skb;
337 
338 err:
339 	dev->stats.rx_dropped++;
340 	give_pages(rq, page);
341 	return NULL;
342 }
343 
344 static struct sk_buff *receive_mergeable(struct net_device *dev,
345 					 struct virtnet_info *vi,
346 					 struct receive_queue *rq,
347 					 unsigned long ctx,
348 					 unsigned int len)
349 {
350 	void *buf = mergeable_ctx_to_buf_address(ctx);
351 	struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
352 	u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
353 	struct page *page = virt_to_head_page(buf);
354 	int offset = buf - page_address(page);
355 	unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
356 
357 	struct sk_buff *head_skb = page_to_skb(vi, rq, page, offset, len,
358 					       truesize);
359 	struct sk_buff *curr_skb = head_skb;
360 
361 	if (unlikely(!curr_skb))
362 		goto err_skb;
363 	while (--num_buf) {
364 		int num_skb_frags;
365 
366 		ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
367 		if (unlikely(!ctx)) {
368 			pr_debug("%s: rx error: %d buffers out of %d missing\n",
369 				 dev->name, num_buf,
370 				 virtio16_to_cpu(vi->vdev,
371 						 hdr->num_buffers));
372 			dev->stats.rx_length_errors++;
373 			goto err_buf;
374 		}
375 
376 		buf = mergeable_ctx_to_buf_address(ctx);
377 		page = virt_to_head_page(buf);
378 
379 		num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
380 		if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
381 			struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
382 
383 			if (unlikely(!nskb))
384 				goto err_skb;
385 			if (curr_skb == head_skb)
386 				skb_shinfo(curr_skb)->frag_list = nskb;
387 			else
388 				curr_skb->next = nskb;
389 			curr_skb = nskb;
390 			head_skb->truesize += nskb->truesize;
391 			num_skb_frags = 0;
392 		}
393 		truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
394 		if (curr_skb != head_skb) {
395 			head_skb->data_len += len;
396 			head_skb->len += len;
397 			head_skb->truesize += truesize;
398 		}
399 		offset = buf - page_address(page);
400 		if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
401 			put_page(page);
402 			skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
403 					     len, truesize);
404 		} else {
405 			skb_add_rx_frag(curr_skb, num_skb_frags, page,
406 					offset, len, truesize);
407 		}
408 	}
409 
410 	ewma_add(&rq->mrg_avg_pkt_len, head_skb->len);
411 	return head_skb;
412 
413 err_skb:
414 	put_page(page);
415 	while (--num_buf) {
416 		ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
417 		if (unlikely(!ctx)) {
418 			pr_debug("%s: rx error: %d buffers missing\n",
419 				 dev->name, num_buf);
420 			dev->stats.rx_length_errors++;
421 			break;
422 		}
423 		page = virt_to_head_page(mergeable_ctx_to_buf_address(ctx));
424 		put_page(page);
425 	}
426 err_buf:
427 	dev->stats.rx_dropped++;
428 	dev_kfree_skb(head_skb);
429 	return NULL;
430 }
431 
432 static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
433 			void *buf, unsigned int len)
434 {
435 	struct net_device *dev = vi->dev;
436 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
437 	struct sk_buff *skb;
438 	struct virtio_net_hdr_mrg_rxbuf *hdr;
439 
440 	if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
441 		pr_debug("%s: short packet %i\n", dev->name, len);
442 		dev->stats.rx_length_errors++;
443 		if (vi->mergeable_rx_bufs) {
444 			unsigned long ctx = (unsigned long)buf;
445 			void *base = mergeable_ctx_to_buf_address(ctx);
446 			put_page(virt_to_head_page(base));
447 		} else if (vi->big_packets) {
448 			give_pages(rq, buf);
449 		} else {
450 			dev_kfree_skb(buf);
451 		}
452 		return;
453 	}
454 
455 	if (vi->mergeable_rx_bufs)
456 		skb = receive_mergeable(dev, vi, rq, (unsigned long)buf, len);
457 	else if (vi->big_packets)
458 		skb = receive_big(dev, vi, rq, buf, len);
459 	else
460 		skb = receive_small(vi, buf, len);
461 
462 	if (unlikely(!skb))
463 		return;
464 
465 	hdr = skb_vnet_hdr(skb);
466 
467 	u64_stats_update_begin(&stats->rx_syncp);
468 	stats->rx_bytes += skb->len;
469 	stats->rx_packets++;
470 	u64_stats_update_end(&stats->rx_syncp);
471 
472 	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
473 		pr_debug("Needs csum!\n");
474 		if (!skb_partial_csum_set(skb,
475 			  virtio16_to_cpu(vi->vdev, hdr->hdr.csum_start),
476 			  virtio16_to_cpu(vi->vdev, hdr->hdr.csum_offset)))
477 			goto frame_err;
478 	} else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
479 		skb->ip_summed = CHECKSUM_UNNECESSARY;
480 	}
481 
482 	skb->protocol = eth_type_trans(skb, dev);
483 	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
484 		 ntohs(skb->protocol), skb->len, skb->pkt_type);
485 
486 	if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
487 		pr_debug("GSO!\n");
488 		switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
489 		case VIRTIO_NET_HDR_GSO_TCPV4:
490 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
491 			break;
492 		case VIRTIO_NET_HDR_GSO_UDP:
493 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
494 			break;
495 		case VIRTIO_NET_HDR_GSO_TCPV6:
496 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
497 			break;
498 		default:
499 			net_warn_ratelimited("%s: bad gso type %u.\n",
500 					     dev->name, hdr->hdr.gso_type);
501 			goto frame_err;
502 		}
503 
504 		if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
505 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
506 
507 		skb_shinfo(skb)->gso_size = virtio16_to_cpu(vi->vdev,
508 							    hdr->hdr.gso_size);
509 		if (skb_shinfo(skb)->gso_size == 0) {
510 			net_warn_ratelimited("%s: zero gso size.\n", dev->name);
511 			goto frame_err;
512 		}
513 
514 		/* Header must be checked, and gso_segs computed. */
515 		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
516 		skb_shinfo(skb)->gso_segs = 0;
517 	}
518 
519 	skb_mark_napi_id(skb, &rq->napi);
520 
521 	netif_receive_skb(skb);
522 	return;
523 
524 frame_err:
525 	dev->stats.rx_frame_errors++;
526 	dev_kfree_skb(skb);
527 }
528 
529 static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
530 			     gfp_t gfp)
531 {
532 	struct sk_buff *skb;
533 	struct virtio_net_hdr_mrg_rxbuf *hdr;
534 	int err;
535 
536 	skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
537 	if (unlikely(!skb))
538 		return -ENOMEM;
539 
540 	skb_put(skb, GOOD_PACKET_LEN);
541 
542 	hdr = skb_vnet_hdr(skb);
543 	sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
544 	sg_set_buf(rq->sg, hdr, vi->hdr_len);
545 	skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
546 
547 	err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
548 	if (err < 0)
549 		dev_kfree_skb(skb);
550 
551 	return err;
552 }
553 
554 static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
555 			   gfp_t gfp)
556 {
557 	struct page *first, *list = NULL;
558 	char *p;
559 	int i, err, offset;
560 
561 	sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
562 
563 	/* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
564 	for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
565 		first = get_a_page(rq, gfp);
566 		if (!first) {
567 			if (list)
568 				give_pages(rq, list);
569 			return -ENOMEM;
570 		}
571 		sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
572 
573 		/* chain new page in list head to match sg */
574 		first->private = (unsigned long)list;
575 		list = first;
576 	}
577 
578 	first = get_a_page(rq, gfp);
579 	if (!first) {
580 		give_pages(rq, list);
581 		return -ENOMEM;
582 	}
583 	p = page_address(first);
584 
585 	/* rq->sg[0], rq->sg[1] share the same page */
586 	/* a separated rq->sg[0] for header - required in case !any_header_sg */
587 	sg_set_buf(&rq->sg[0], p, vi->hdr_len);
588 
589 	/* rq->sg[1] for data packet, from offset */
590 	offset = sizeof(struct padded_vnet_hdr);
591 	sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
592 
593 	/* chain first in list head */
594 	first->private = (unsigned long)list;
595 	err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
596 				  first, gfp);
597 	if (err < 0)
598 		give_pages(rq, first);
599 
600 	return err;
601 }
602 
603 static unsigned int get_mergeable_buf_len(struct ewma *avg_pkt_len)
604 {
605 	const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
606 	unsigned int len;
607 
608 	len = hdr_len + clamp_t(unsigned int, ewma_read(avg_pkt_len),
609 			GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
610 	return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
611 }
612 
613 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
614 {
615 	struct page_frag *alloc_frag = &rq->alloc_frag;
616 	char *buf;
617 	unsigned long ctx;
618 	int err;
619 	unsigned int len, hole;
620 
621 	len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
622 	if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
623 		return -ENOMEM;
624 
625 	buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
626 	ctx = mergeable_buf_to_ctx(buf, len);
627 	get_page(alloc_frag->page);
628 	alloc_frag->offset += len;
629 	hole = alloc_frag->size - alloc_frag->offset;
630 	if (hole < len) {
631 		/* To avoid internal fragmentation, if there is very likely not
632 		 * enough space for another buffer, add the remaining space to
633 		 * the current buffer. This extra space is not included in
634 		 * the truesize stored in ctx.
635 		 */
636 		len += hole;
637 		alloc_frag->offset += hole;
638 	}
639 
640 	sg_init_one(rq->sg, buf, len);
641 	err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, (void *)ctx, gfp);
642 	if (err < 0)
643 		put_page(virt_to_head_page(buf));
644 
645 	return err;
646 }
647 
648 /*
649  * Returns false if we couldn't fill entirely (OOM).
650  *
651  * Normally run in the receive path, but can also be run from ndo_open
652  * before we're receiving packets, or from refill_work which is
653  * careful to disable receiving (using napi_disable).
654  */
655 static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
656 			  gfp_t gfp)
657 {
658 	int err;
659 	bool oom;
660 
661 	gfp |= __GFP_COLD;
662 	do {
663 		if (vi->mergeable_rx_bufs)
664 			err = add_recvbuf_mergeable(rq, gfp);
665 		else if (vi->big_packets)
666 			err = add_recvbuf_big(vi, rq, gfp);
667 		else
668 			err = add_recvbuf_small(vi, rq, gfp);
669 
670 		oom = err == -ENOMEM;
671 		if (err)
672 			break;
673 	} while (rq->vq->num_free);
674 	virtqueue_kick(rq->vq);
675 	return !oom;
676 }
677 
678 static void skb_recv_done(struct virtqueue *rvq)
679 {
680 	struct virtnet_info *vi = rvq->vdev->priv;
681 	struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
682 
683 	/* Schedule NAPI, Suppress further interrupts if successful. */
684 	if (napi_schedule_prep(&rq->napi)) {
685 		virtqueue_disable_cb(rvq);
686 		__napi_schedule(&rq->napi);
687 	}
688 }
689 
690 static void virtnet_napi_enable(struct receive_queue *rq)
691 {
692 	napi_enable(&rq->napi);
693 
694 	/* If all buffers were filled by other side before we napi_enabled, we
695 	 * won't get another interrupt, so process any outstanding packets
696 	 * now.  virtnet_poll wants re-enable the queue, so we disable here.
697 	 * We synchronize against interrupts via NAPI_STATE_SCHED */
698 	if (napi_schedule_prep(&rq->napi)) {
699 		virtqueue_disable_cb(rq->vq);
700 		local_bh_disable();
701 		__napi_schedule(&rq->napi);
702 		local_bh_enable();
703 	}
704 }
705 
706 static void refill_work(struct work_struct *work)
707 {
708 	struct virtnet_info *vi =
709 		container_of(work, struct virtnet_info, refill.work);
710 	bool still_empty;
711 	int i;
712 
713 	for (i = 0; i < vi->curr_queue_pairs; i++) {
714 		struct receive_queue *rq = &vi->rq[i];
715 
716 		napi_disable(&rq->napi);
717 		still_empty = !try_fill_recv(vi, rq, GFP_KERNEL);
718 		virtnet_napi_enable(rq);
719 
720 		/* In theory, this can happen: if we don't get any buffers in
721 		 * we will *never* try to fill again.
722 		 */
723 		if (still_empty)
724 			schedule_delayed_work(&vi->refill, HZ/2);
725 	}
726 }
727 
728 static int virtnet_receive(struct receive_queue *rq, int budget)
729 {
730 	struct virtnet_info *vi = rq->vq->vdev->priv;
731 	unsigned int len, received = 0;
732 	void *buf;
733 
734 	while (received < budget &&
735 	       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
736 		receive_buf(vi, rq, buf, len);
737 		received++;
738 	}
739 
740 	if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
741 		if (!try_fill_recv(vi, rq, GFP_ATOMIC))
742 			schedule_delayed_work(&vi->refill, 0);
743 	}
744 
745 	return received;
746 }
747 
748 static int virtnet_poll(struct napi_struct *napi, int budget)
749 {
750 	struct receive_queue *rq =
751 		container_of(napi, struct receive_queue, napi);
752 	unsigned int r, received;
753 
754 	received = virtnet_receive(rq, budget);
755 
756 	/* Out of packets? */
757 	if (received < budget) {
758 		r = virtqueue_enable_cb_prepare(rq->vq);
759 		napi_complete(napi);
760 		if (unlikely(virtqueue_poll(rq->vq, r)) &&
761 		    napi_schedule_prep(napi)) {
762 			virtqueue_disable_cb(rq->vq);
763 			__napi_schedule(napi);
764 		}
765 	}
766 
767 	return received;
768 }
769 
770 #ifdef CONFIG_NET_RX_BUSY_POLL
771 /* must be called with local_bh_disable()d */
772 static int virtnet_busy_poll(struct napi_struct *napi)
773 {
774 	struct receive_queue *rq =
775 		container_of(napi, struct receive_queue, napi);
776 	struct virtnet_info *vi = rq->vq->vdev->priv;
777 	int r, received = 0, budget = 4;
778 
779 	if (!(vi->status & VIRTIO_NET_S_LINK_UP))
780 		return LL_FLUSH_FAILED;
781 
782 	if (!napi_schedule_prep(napi))
783 		return LL_FLUSH_BUSY;
784 
785 	virtqueue_disable_cb(rq->vq);
786 
787 again:
788 	received += virtnet_receive(rq, budget);
789 
790 	r = virtqueue_enable_cb_prepare(rq->vq);
791 	clear_bit(NAPI_STATE_SCHED, &napi->state);
792 	if (unlikely(virtqueue_poll(rq->vq, r)) &&
793 	    napi_schedule_prep(napi)) {
794 		virtqueue_disable_cb(rq->vq);
795 		if (received < budget) {
796 			budget -= received;
797 			goto again;
798 		} else {
799 			__napi_schedule(napi);
800 		}
801 	}
802 
803 	return received;
804 }
805 #endif	/* CONFIG_NET_RX_BUSY_POLL */
806 
807 static int virtnet_open(struct net_device *dev)
808 {
809 	struct virtnet_info *vi = netdev_priv(dev);
810 	int i;
811 
812 	for (i = 0; i < vi->max_queue_pairs; i++) {
813 		if (i < vi->curr_queue_pairs)
814 			/* Make sure we have some buffers: if oom use wq. */
815 			if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
816 				schedule_delayed_work(&vi->refill, 0);
817 		virtnet_napi_enable(&vi->rq[i]);
818 	}
819 
820 	return 0;
821 }
822 
823 static void free_old_xmit_skbs(struct send_queue *sq)
824 {
825 	struct sk_buff *skb;
826 	unsigned int len;
827 	struct virtnet_info *vi = sq->vq->vdev->priv;
828 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
829 
830 	while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
831 		pr_debug("Sent skb %p\n", skb);
832 
833 		u64_stats_update_begin(&stats->tx_syncp);
834 		stats->tx_bytes += skb->len;
835 		stats->tx_packets++;
836 		u64_stats_update_end(&stats->tx_syncp);
837 
838 		dev_kfree_skb_any(skb);
839 	}
840 }
841 
842 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
843 {
844 	struct virtio_net_hdr_mrg_rxbuf *hdr;
845 	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
846 	struct virtnet_info *vi = sq->vq->vdev->priv;
847 	unsigned num_sg;
848 	unsigned hdr_len = vi->hdr_len;
849 	bool can_push;
850 
851 	pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
852 
853 	can_push = vi->any_header_sg &&
854 		!((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
855 		!skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
856 	/* Even if we can, don't push here yet as this would skew
857 	 * csum_start offset below. */
858 	if (can_push)
859 		hdr = (struct virtio_net_hdr_mrg_rxbuf *)(skb->data - hdr_len);
860 	else
861 		hdr = skb_vnet_hdr(skb);
862 
863 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
864 		hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
865 		hdr->hdr.csum_start = cpu_to_virtio16(vi->vdev,
866 						skb_checksum_start_offset(skb));
867 		hdr->hdr.csum_offset = cpu_to_virtio16(vi->vdev,
868 							 skb->csum_offset);
869 	} else {
870 		hdr->hdr.flags = 0;
871 		hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
872 	}
873 
874 	if (skb_is_gso(skb)) {
875 		hdr->hdr.hdr_len = cpu_to_virtio16(vi->vdev, skb_headlen(skb));
876 		hdr->hdr.gso_size = cpu_to_virtio16(vi->vdev,
877 						    skb_shinfo(skb)->gso_size);
878 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
879 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
880 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
881 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
882 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
883 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
884 		else
885 			BUG();
886 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
887 			hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
888 	} else {
889 		hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
890 		hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
891 	}
892 
893 	if (vi->mergeable_rx_bufs)
894 		hdr->num_buffers = 0;
895 
896 	sg_init_table(sq->sg, MAX_SKB_FRAGS + 2);
897 	if (can_push) {
898 		__skb_push(skb, hdr_len);
899 		num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
900 		/* Pull header back to avoid skew in tx bytes calculations. */
901 		__skb_pull(skb, hdr_len);
902 	} else {
903 		sg_set_buf(sq->sg, hdr, hdr_len);
904 		num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
905 	}
906 	return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
907 }
908 
909 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
910 {
911 	struct virtnet_info *vi = netdev_priv(dev);
912 	int qnum = skb_get_queue_mapping(skb);
913 	struct send_queue *sq = &vi->sq[qnum];
914 	int err;
915 	struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
916 	bool kick = !skb->xmit_more;
917 
918 	/* Free up any pending old buffers before queueing new ones. */
919 	free_old_xmit_skbs(sq);
920 
921 	/* timestamp packet in software */
922 	skb_tx_timestamp(skb);
923 
924 	/* Try to transmit */
925 	err = xmit_skb(sq, skb);
926 
927 	/* This should not happen! */
928 	if (unlikely(err)) {
929 		dev->stats.tx_fifo_errors++;
930 		if (net_ratelimit())
931 			dev_warn(&dev->dev,
932 				 "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
933 		dev->stats.tx_dropped++;
934 		dev_kfree_skb_any(skb);
935 		return NETDEV_TX_OK;
936 	}
937 
938 	/* Don't wait up for transmitted skbs to be freed. */
939 	skb_orphan(skb);
940 	nf_reset(skb);
941 
942 	/* If running out of space, stop queue to avoid getting packets that we
943 	 * are then unable to transmit.
944 	 * An alternative would be to force queuing layer to requeue the skb by
945 	 * returning NETDEV_TX_BUSY. However, NETDEV_TX_BUSY should not be
946 	 * returned in a normal path of operation: it means that driver is not
947 	 * maintaining the TX queue stop/start state properly, and causes
948 	 * the stack to do a non-trivial amount of useless work.
949 	 * Since most packets only take 1 or 2 ring slots, stopping the queue
950 	 * early means 16 slots are typically wasted.
951 	 */
952 	if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
953 		netif_stop_subqueue(dev, qnum);
954 		if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
955 			/* More just got used, free them then recheck. */
956 			free_old_xmit_skbs(sq);
957 			if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
958 				netif_start_subqueue(dev, qnum);
959 				virtqueue_disable_cb(sq->vq);
960 			}
961 		}
962 	}
963 
964 	if (kick || netif_xmit_stopped(txq))
965 		virtqueue_kick(sq->vq);
966 
967 	return NETDEV_TX_OK;
968 }
969 
970 /*
971  * Send command via the control virtqueue and check status.  Commands
972  * supported by the hypervisor, as indicated by feature bits, should
973  * never fail unless improperly formatted.
974  */
975 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
976 				 struct scatterlist *out)
977 {
978 	struct scatterlist *sgs[4], hdr, stat;
979 	struct virtio_net_ctrl_hdr ctrl;
980 	virtio_net_ctrl_ack status = ~0;
981 	unsigned out_num = 0, tmp;
982 
983 	/* Caller should know better */
984 	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
985 
986 	ctrl.class = class;
987 	ctrl.cmd = cmd;
988 	/* Add header */
989 	sg_init_one(&hdr, &ctrl, sizeof(ctrl));
990 	sgs[out_num++] = &hdr;
991 
992 	if (out)
993 		sgs[out_num++] = out;
994 
995 	/* Add return status. */
996 	sg_init_one(&stat, &status, sizeof(status));
997 	sgs[out_num] = &stat;
998 
999 	BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
1000 	virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
1001 
1002 	if (unlikely(!virtqueue_kick(vi->cvq)))
1003 		return status == VIRTIO_NET_OK;
1004 
1005 	/* Spin for a response, the kick causes an ioport write, trapping
1006 	 * into the hypervisor, so the request should be handled immediately.
1007 	 */
1008 	while (!virtqueue_get_buf(vi->cvq, &tmp) &&
1009 	       !virtqueue_is_broken(vi->cvq))
1010 		cpu_relax();
1011 
1012 	return status == VIRTIO_NET_OK;
1013 }
1014 
1015 static int virtnet_set_mac_address(struct net_device *dev, void *p)
1016 {
1017 	struct virtnet_info *vi = netdev_priv(dev);
1018 	struct virtio_device *vdev = vi->vdev;
1019 	int ret;
1020 	struct sockaddr *addr = p;
1021 	struct scatterlist sg;
1022 
1023 	ret = eth_prepare_mac_addr_change(dev, p);
1024 	if (ret)
1025 		return ret;
1026 
1027 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
1028 		sg_init_one(&sg, addr->sa_data, dev->addr_len);
1029 		if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1030 					  VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
1031 			dev_warn(&vdev->dev,
1032 				 "Failed to set mac address by vq command.\n");
1033 			return -EINVAL;
1034 		}
1035 	} else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC) &&
1036 		   !virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1037 		unsigned int i;
1038 
1039 		/* Naturally, this has an atomicity problem. */
1040 		for (i = 0; i < dev->addr_len; i++)
1041 			virtio_cwrite8(vdev,
1042 				       offsetof(struct virtio_net_config, mac) +
1043 				       i, addr->sa_data[i]);
1044 	}
1045 
1046 	eth_commit_mac_addr_change(dev, p);
1047 
1048 	return 0;
1049 }
1050 
1051 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
1052 					       struct rtnl_link_stats64 *tot)
1053 {
1054 	struct virtnet_info *vi = netdev_priv(dev);
1055 	int cpu;
1056 	unsigned int start;
1057 
1058 	for_each_possible_cpu(cpu) {
1059 		struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
1060 		u64 tpackets, tbytes, rpackets, rbytes;
1061 
1062 		do {
1063 			start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
1064 			tpackets = stats->tx_packets;
1065 			tbytes   = stats->tx_bytes;
1066 		} while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
1067 
1068 		do {
1069 			start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
1070 			rpackets = stats->rx_packets;
1071 			rbytes   = stats->rx_bytes;
1072 		} while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
1073 
1074 		tot->rx_packets += rpackets;
1075 		tot->tx_packets += tpackets;
1076 		tot->rx_bytes   += rbytes;
1077 		tot->tx_bytes   += tbytes;
1078 	}
1079 
1080 	tot->tx_dropped = dev->stats.tx_dropped;
1081 	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
1082 	tot->rx_dropped = dev->stats.rx_dropped;
1083 	tot->rx_length_errors = dev->stats.rx_length_errors;
1084 	tot->rx_frame_errors = dev->stats.rx_frame_errors;
1085 
1086 	return tot;
1087 }
1088 
1089 #ifdef CONFIG_NET_POLL_CONTROLLER
1090 static void virtnet_netpoll(struct net_device *dev)
1091 {
1092 	struct virtnet_info *vi = netdev_priv(dev);
1093 	int i;
1094 
1095 	for (i = 0; i < vi->curr_queue_pairs; i++)
1096 		napi_schedule(&vi->rq[i].napi);
1097 }
1098 #endif
1099 
1100 static void virtnet_ack_link_announce(struct virtnet_info *vi)
1101 {
1102 	rtnl_lock();
1103 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
1104 				  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
1105 		dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
1106 	rtnl_unlock();
1107 }
1108 
1109 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
1110 {
1111 	struct scatterlist sg;
1112 	struct virtio_net_ctrl_mq s;
1113 	struct net_device *dev = vi->dev;
1114 
1115 	if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
1116 		return 0;
1117 
1118 	s.virtqueue_pairs = cpu_to_virtio16(vi->vdev, queue_pairs);
1119 	sg_init_one(&sg, &s, sizeof(s));
1120 
1121 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
1122 				  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
1123 		dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
1124 			 queue_pairs);
1125 		return -EINVAL;
1126 	} else {
1127 		vi->curr_queue_pairs = queue_pairs;
1128 		/* virtnet_open() will refill when device is going to up. */
1129 		if (dev->flags & IFF_UP)
1130 			schedule_delayed_work(&vi->refill, 0);
1131 	}
1132 
1133 	return 0;
1134 }
1135 
1136 static int virtnet_close(struct net_device *dev)
1137 {
1138 	struct virtnet_info *vi = netdev_priv(dev);
1139 	int i;
1140 
1141 	/* Make sure refill_work doesn't re-enable napi! */
1142 	cancel_delayed_work_sync(&vi->refill);
1143 
1144 	for (i = 0; i < vi->max_queue_pairs; i++)
1145 		napi_disable(&vi->rq[i].napi);
1146 
1147 	return 0;
1148 }
1149 
1150 static void virtnet_set_rx_mode(struct net_device *dev)
1151 {
1152 	struct virtnet_info *vi = netdev_priv(dev);
1153 	struct scatterlist sg[2];
1154 	u8 promisc, allmulti;
1155 	struct virtio_net_ctrl_mac *mac_data;
1156 	struct netdev_hw_addr *ha;
1157 	int uc_count;
1158 	int mc_count;
1159 	void *buf;
1160 	int i;
1161 
1162 	/* We can't dynamically set ndo_set_rx_mode, so return gracefully */
1163 	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
1164 		return;
1165 
1166 	promisc = ((dev->flags & IFF_PROMISC) != 0);
1167 	allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
1168 
1169 	sg_init_one(sg, &promisc, sizeof(promisc));
1170 
1171 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1172 				  VIRTIO_NET_CTRL_RX_PROMISC, sg))
1173 		dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
1174 			 promisc ? "en" : "dis");
1175 
1176 	sg_init_one(sg, &allmulti, sizeof(allmulti));
1177 
1178 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1179 				  VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
1180 		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
1181 			 allmulti ? "en" : "dis");
1182 
1183 	uc_count = netdev_uc_count(dev);
1184 	mc_count = netdev_mc_count(dev);
1185 	/* MAC filter - use one buffer for both lists */
1186 	buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
1187 		      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
1188 	mac_data = buf;
1189 	if (!buf)
1190 		return;
1191 
1192 	sg_init_table(sg, 2);
1193 
1194 	/* Store the unicast list and count in the front of the buffer */
1195 	mac_data->entries = cpu_to_virtio32(vi->vdev, uc_count);
1196 	i = 0;
1197 	netdev_for_each_uc_addr(ha, dev)
1198 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1199 
1200 	sg_set_buf(&sg[0], mac_data,
1201 		   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
1202 
1203 	/* multicast list and count fill the end */
1204 	mac_data = (void *)&mac_data->macs[uc_count][0];
1205 
1206 	mac_data->entries = cpu_to_virtio32(vi->vdev, mc_count);
1207 	i = 0;
1208 	netdev_for_each_mc_addr(ha, dev)
1209 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1210 
1211 	sg_set_buf(&sg[1], mac_data,
1212 		   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1213 
1214 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1215 				  VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
1216 		dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
1217 
1218 	kfree(buf);
1219 }
1220 
1221 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1222 				   __be16 proto, u16 vid)
1223 {
1224 	struct virtnet_info *vi = netdev_priv(dev);
1225 	struct scatterlist sg;
1226 
1227 	sg_init_one(&sg, &vid, sizeof(vid));
1228 
1229 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1230 				  VIRTIO_NET_CTRL_VLAN_ADD, &sg))
1231 		dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1232 	return 0;
1233 }
1234 
1235 static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1236 				    __be16 proto, u16 vid)
1237 {
1238 	struct virtnet_info *vi = netdev_priv(dev);
1239 	struct scatterlist sg;
1240 
1241 	sg_init_one(&sg, &vid, sizeof(vid));
1242 
1243 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1244 				  VIRTIO_NET_CTRL_VLAN_DEL, &sg))
1245 		dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1246 	return 0;
1247 }
1248 
1249 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1250 {
1251 	int i;
1252 
1253 	if (vi->affinity_hint_set) {
1254 		for (i = 0; i < vi->max_queue_pairs; i++) {
1255 			virtqueue_set_affinity(vi->rq[i].vq, -1);
1256 			virtqueue_set_affinity(vi->sq[i].vq, -1);
1257 		}
1258 
1259 		vi->affinity_hint_set = false;
1260 	}
1261 }
1262 
1263 static void virtnet_set_affinity(struct virtnet_info *vi)
1264 {
1265 	int i;
1266 	int cpu;
1267 
1268 	/* In multiqueue mode, when the number of cpu is equal to the number of
1269 	 * queue pairs, we let the queue pairs to be private to one cpu by
1270 	 * setting the affinity hint to eliminate the contention.
1271 	 */
1272 	if (vi->curr_queue_pairs == 1 ||
1273 	    vi->max_queue_pairs != num_online_cpus()) {
1274 		virtnet_clean_affinity(vi, -1);
1275 		return;
1276 	}
1277 
1278 	i = 0;
1279 	for_each_online_cpu(cpu) {
1280 		virtqueue_set_affinity(vi->rq[i].vq, cpu);
1281 		virtqueue_set_affinity(vi->sq[i].vq, cpu);
1282 		netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
1283 		i++;
1284 	}
1285 
1286 	vi->affinity_hint_set = true;
1287 }
1288 
1289 static int virtnet_cpu_callback(struct notifier_block *nfb,
1290 			        unsigned long action, void *hcpu)
1291 {
1292 	struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1293 
1294 	switch(action & ~CPU_TASKS_FROZEN) {
1295 	case CPU_ONLINE:
1296 	case CPU_DOWN_FAILED:
1297 	case CPU_DEAD:
1298 		virtnet_set_affinity(vi);
1299 		break;
1300 	case CPU_DOWN_PREPARE:
1301 		virtnet_clean_affinity(vi, (long)hcpu);
1302 		break;
1303 	default:
1304 		break;
1305 	}
1306 
1307 	return NOTIFY_OK;
1308 }
1309 
1310 static void virtnet_get_ringparam(struct net_device *dev,
1311 				struct ethtool_ringparam *ring)
1312 {
1313 	struct virtnet_info *vi = netdev_priv(dev);
1314 
1315 	ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1316 	ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1317 	ring->rx_pending = ring->rx_max_pending;
1318 	ring->tx_pending = ring->tx_max_pending;
1319 }
1320 
1321 
1322 static void virtnet_get_drvinfo(struct net_device *dev,
1323 				struct ethtool_drvinfo *info)
1324 {
1325 	struct virtnet_info *vi = netdev_priv(dev);
1326 	struct virtio_device *vdev = vi->vdev;
1327 
1328 	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1329 	strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1330 	strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1331 
1332 }
1333 
1334 /* TODO: Eliminate OOO packets during switching */
1335 static int virtnet_set_channels(struct net_device *dev,
1336 				struct ethtool_channels *channels)
1337 {
1338 	struct virtnet_info *vi = netdev_priv(dev);
1339 	u16 queue_pairs = channels->combined_count;
1340 	int err;
1341 
1342 	/* We don't support separate rx/tx channels.
1343 	 * We don't allow setting 'other' channels.
1344 	 */
1345 	if (channels->rx_count || channels->tx_count || channels->other_count)
1346 		return -EINVAL;
1347 
1348 	if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
1349 		return -EINVAL;
1350 
1351 	get_online_cpus();
1352 	err = virtnet_set_queues(vi, queue_pairs);
1353 	if (!err) {
1354 		netif_set_real_num_tx_queues(dev, queue_pairs);
1355 		netif_set_real_num_rx_queues(dev, queue_pairs);
1356 
1357 		virtnet_set_affinity(vi);
1358 	}
1359 	put_online_cpus();
1360 
1361 	return err;
1362 }
1363 
1364 static void virtnet_get_channels(struct net_device *dev,
1365 				 struct ethtool_channels *channels)
1366 {
1367 	struct virtnet_info *vi = netdev_priv(dev);
1368 
1369 	channels->combined_count = vi->curr_queue_pairs;
1370 	channels->max_combined = vi->max_queue_pairs;
1371 	channels->max_other = 0;
1372 	channels->rx_count = 0;
1373 	channels->tx_count = 0;
1374 	channels->other_count = 0;
1375 }
1376 
1377 static const struct ethtool_ops virtnet_ethtool_ops = {
1378 	.get_drvinfo = virtnet_get_drvinfo,
1379 	.get_link = ethtool_op_get_link,
1380 	.get_ringparam = virtnet_get_ringparam,
1381 	.set_channels = virtnet_set_channels,
1382 	.get_channels = virtnet_get_channels,
1383 	.get_ts_info = ethtool_op_get_ts_info,
1384 };
1385 
1386 #define MIN_MTU 68
1387 #define MAX_MTU 65535
1388 
1389 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1390 {
1391 	if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1392 		return -EINVAL;
1393 	dev->mtu = new_mtu;
1394 	return 0;
1395 }
1396 
1397 static const struct net_device_ops virtnet_netdev = {
1398 	.ndo_open            = virtnet_open,
1399 	.ndo_stop   	     = virtnet_close,
1400 	.ndo_start_xmit      = start_xmit,
1401 	.ndo_validate_addr   = eth_validate_addr,
1402 	.ndo_set_mac_address = virtnet_set_mac_address,
1403 	.ndo_set_rx_mode     = virtnet_set_rx_mode,
1404 	.ndo_change_mtu	     = virtnet_change_mtu,
1405 	.ndo_get_stats64     = virtnet_stats,
1406 	.ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1407 	.ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1408 #ifdef CONFIG_NET_POLL_CONTROLLER
1409 	.ndo_poll_controller = virtnet_netpoll,
1410 #endif
1411 #ifdef CONFIG_NET_RX_BUSY_POLL
1412 	.ndo_busy_poll		= virtnet_busy_poll,
1413 #endif
1414 };
1415 
1416 static void virtnet_config_changed_work(struct work_struct *work)
1417 {
1418 	struct virtnet_info *vi =
1419 		container_of(work, struct virtnet_info, config_work);
1420 	u16 v;
1421 
1422 	if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
1423 				 struct virtio_net_config, status, &v) < 0)
1424 		return;
1425 
1426 	if (v & VIRTIO_NET_S_ANNOUNCE) {
1427 		netdev_notify_peers(vi->dev);
1428 		virtnet_ack_link_announce(vi);
1429 	}
1430 
1431 	/* Ignore unknown (future) status bits */
1432 	v &= VIRTIO_NET_S_LINK_UP;
1433 
1434 	if (vi->status == v)
1435 		return;
1436 
1437 	vi->status = v;
1438 
1439 	if (vi->status & VIRTIO_NET_S_LINK_UP) {
1440 		netif_carrier_on(vi->dev);
1441 		netif_tx_wake_all_queues(vi->dev);
1442 	} else {
1443 		netif_carrier_off(vi->dev);
1444 		netif_tx_stop_all_queues(vi->dev);
1445 	}
1446 }
1447 
1448 static void virtnet_config_changed(struct virtio_device *vdev)
1449 {
1450 	struct virtnet_info *vi = vdev->priv;
1451 
1452 	schedule_work(&vi->config_work);
1453 }
1454 
1455 static void virtnet_free_queues(struct virtnet_info *vi)
1456 {
1457 	int i;
1458 
1459 	for (i = 0; i < vi->max_queue_pairs; i++) {
1460 		napi_hash_del(&vi->rq[i].napi);
1461 		netif_napi_del(&vi->rq[i].napi);
1462 	}
1463 
1464 	kfree(vi->rq);
1465 	kfree(vi->sq);
1466 }
1467 
1468 static void free_receive_bufs(struct virtnet_info *vi)
1469 {
1470 	int i;
1471 
1472 	for (i = 0; i < vi->max_queue_pairs; i++) {
1473 		while (vi->rq[i].pages)
1474 			__free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1475 	}
1476 }
1477 
1478 static void free_receive_page_frags(struct virtnet_info *vi)
1479 {
1480 	int i;
1481 	for (i = 0; i < vi->max_queue_pairs; i++)
1482 		if (vi->rq[i].alloc_frag.page)
1483 			put_page(vi->rq[i].alloc_frag.page);
1484 }
1485 
1486 static void free_unused_bufs(struct virtnet_info *vi)
1487 {
1488 	void *buf;
1489 	int i;
1490 
1491 	for (i = 0; i < vi->max_queue_pairs; i++) {
1492 		struct virtqueue *vq = vi->sq[i].vq;
1493 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1494 			dev_kfree_skb(buf);
1495 	}
1496 
1497 	for (i = 0; i < vi->max_queue_pairs; i++) {
1498 		struct virtqueue *vq = vi->rq[i].vq;
1499 
1500 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1501 			if (vi->mergeable_rx_bufs) {
1502 				unsigned long ctx = (unsigned long)buf;
1503 				void *base = mergeable_ctx_to_buf_address(ctx);
1504 				put_page(virt_to_head_page(base));
1505 			} else if (vi->big_packets) {
1506 				give_pages(&vi->rq[i], buf);
1507 			} else {
1508 				dev_kfree_skb(buf);
1509 			}
1510 		}
1511 	}
1512 }
1513 
1514 static void virtnet_del_vqs(struct virtnet_info *vi)
1515 {
1516 	struct virtio_device *vdev = vi->vdev;
1517 
1518 	virtnet_clean_affinity(vi, -1);
1519 
1520 	vdev->config->del_vqs(vdev);
1521 
1522 	virtnet_free_queues(vi);
1523 }
1524 
1525 static int virtnet_find_vqs(struct virtnet_info *vi)
1526 {
1527 	vq_callback_t **callbacks;
1528 	struct virtqueue **vqs;
1529 	int ret = -ENOMEM;
1530 	int i, total_vqs;
1531 	const char **names;
1532 
1533 	/* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1534 	 * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1535 	 * possible control vq.
1536 	 */
1537 	total_vqs = vi->max_queue_pairs * 2 +
1538 		    virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1539 
1540 	/* Allocate space for find_vqs parameters */
1541 	vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1542 	if (!vqs)
1543 		goto err_vq;
1544 	callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1545 	if (!callbacks)
1546 		goto err_callback;
1547 	names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1548 	if (!names)
1549 		goto err_names;
1550 
1551 	/* Parameters for control virtqueue, if any */
1552 	if (vi->has_cvq) {
1553 		callbacks[total_vqs - 1] = NULL;
1554 		names[total_vqs - 1] = "control";
1555 	}
1556 
1557 	/* Allocate/initialize parameters for send/receive virtqueues */
1558 	for (i = 0; i < vi->max_queue_pairs; i++) {
1559 		callbacks[rxq2vq(i)] = skb_recv_done;
1560 		callbacks[txq2vq(i)] = skb_xmit_done;
1561 		sprintf(vi->rq[i].name, "input.%d", i);
1562 		sprintf(vi->sq[i].name, "output.%d", i);
1563 		names[rxq2vq(i)] = vi->rq[i].name;
1564 		names[txq2vq(i)] = vi->sq[i].name;
1565 	}
1566 
1567 	ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1568 					 names);
1569 	if (ret)
1570 		goto err_find;
1571 
1572 	if (vi->has_cvq) {
1573 		vi->cvq = vqs[total_vqs - 1];
1574 		if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1575 			vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1576 	}
1577 
1578 	for (i = 0; i < vi->max_queue_pairs; i++) {
1579 		vi->rq[i].vq = vqs[rxq2vq(i)];
1580 		vi->sq[i].vq = vqs[txq2vq(i)];
1581 	}
1582 
1583 	kfree(names);
1584 	kfree(callbacks);
1585 	kfree(vqs);
1586 
1587 	return 0;
1588 
1589 err_find:
1590 	kfree(names);
1591 err_names:
1592 	kfree(callbacks);
1593 err_callback:
1594 	kfree(vqs);
1595 err_vq:
1596 	return ret;
1597 }
1598 
1599 static int virtnet_alloc_queues(struct virtnet_info *vi)
1600 {
1601 	int i;
1602 
1603 	vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1604 	if (!vi->sq)
1605 		goto err_sq;
1606 	vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1607 	if (!vi->rq)
1608 		goto err_rq;
1609 
1610 	INIT_DELAYED_WORK(&vi->refill, refill_work);
1611 	for (i = 0; i < vi->max_queue_pairs; i++) {
1612 		vi->rq[i].pages = NULL;
1613 		netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1614 			       napi_weight);
1615 		napi_hash_add(&vi->rq[i].napi);
1616 
1617 		sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1618 		ewma_init(&vi->rq[i].mrg_avg_pkt_len, 1, RECEIVE_AVG_WEIGHT);
1619 		sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1620 	}
1621 
1622 	return 0;
1623 
1624 err_rq:
1625 	kfree(vi->sq);
1626 err_sq:
1627 	return -ENOMEM;
1628 }
1629 
1630 static int init_vqs(struct virtnet_info *vi)
1631 {
1632 	int ret;
1633 
1634 	/* Allocate send & receive queues */
1635 	ret = virtnet_alloc_queues(vi);
1636 	if (ret)
1637 		goto err;
1638 
1639 	ret = virtnet_find_vqs(vi);
1640 	if (ret)
1641 		goto err_free;
1642 
1643 	get_online_cpus();
1644 	virtnet_set_affinity(vi);
1645 	put_online_cpus();
1646 
1647 	return 0;
1648 
1649 err_free:
1650 	virtnet_free_queues(vi);
1651 err:
1652 	return ret;
1653 }
1654 
1655 #ifdef CONFIG_SYSFS
1656 static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
1657 		struct rx_queue_attribute *attribute, char *buf)
1658 {
1659 	struct virtnet_info *vi = netdev_priv(queue->dev);
1660 	unsigned int queue_index = get_netdev_rx_queue_index(queue);
1661 	struct ewma *avg;
1662 
1663 	BUG_ON(queue_index >= vi->max_queue_pairs);
1664 	avg = &vi->rq[queue_index].mrg_avg_pkt_len;
1665 	return sprintf(buf, "%u\n", get_mergeable_buf_len(avg));
1666 }
1667 
1668 static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
1669 	__ATTR_RO(mergeable_rx_buffer_size);
1670 
1671 static struct attribute *virtio_net_mrg_rx_attrs[] = {
1672 	&mergeable_rx_buffer_size_attribute.attr,
1673 	NULL
1674 };
1675 
1676 static const struct attribute_group virtio_net_mrg_rx_group = {
1677 	.name = "virtio_net",
1678 	.attrs = virtio_net_mrg_rx_attrs
1679 };
1680 #endif
1681 
1682 static bool virtnet_fail_on_feature(struct virtio_device *vdev,
1683 				    unsigned int fbit,
1684 				    const char *fname, const char *dname)
1685 {
1686 	if (!virtio_has_feature(vdev, fbit))
1687 		return false;
1688 
1689 	dev_err(&vdev->dev, "device advertises feature %s but not %s",
1690 		fname, dname);
1691 
1692 	return true;
1693 }
1694 
1695 #define VIRTNET_FAIL_ON(vdev, fbit, dbit)			\
1696 	virtnet_fail_on_feature(vdev, fbit, #fbit, dbit)
1697 
1698 static bool virtnet_validate_features(struct virtio_device *vdev)
1699 {
1700 	if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
1701 	    (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
1702 			     "VIRTIO_NET_F_CTRL_VQ") ||
1703 	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
1704 			     "VIRTIO_NET_F_CTRL_VQ") ||
1705 	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
1706 			     "VIRTIO_NET_F_CTRL_VQ") ||
1707 	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") ||
1708 	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
1709 			     "VIRTIO_NET_F_CTRL_VQ"))) {
1710 		return false;
1711 	}
1712 
1713 	return true;
1714 }
1715 
1716 static int virtnet_probe(struct virtio_device *vdev)
1717 {
1718 	int i, err;
1719 	struct net_device *dev;
1720 	struct virtnet_info *vi;
1721 	u16 max_queue_pairs;
1722 
1723 	if (!vdev->config->get) {
1724 		dev_err(&vdev->dev, "%s failure: config access disabled\n",
1725 			__func__);
1726 		return -EINVAL;
1727 	}
1728 
1729 	if (!virtnet_validate_features(vdev))
1730 		return -EINVAL;
1731 
1732 	/* Find if host supports multiqueue virtio_net device */
1733 	err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
1734 				   struct virtio_net_config,
1735 				   max_virtqueue_pairs, &max_queue_pairs);
1736 
1737 	/* We need at least 2 queue's */
1738 	if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1739 	    max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1740 	    !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1741 		max_queue_pairs = 1;
1742 
1743 	/* Allocate ourselves a network device with room for our info */
1744 	dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1745 	if (!dev)
1746 		return -ENOMEM;
1747 
1748 	/* Set up network device as normal. */
1749 	dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1750 	dev->netdev_ops = &virtnet_netdev;
1751 	dev->features = NETIF_F_HIGHDMA;
1752 
1753 	dev->ethtool_ops = &virtnet_ethtool_ops;
1754 	SET_NETDEV_DEV(dev, &vdev->dev);
1755 
1756 	/* Do we support "hardware" checksums? */
1757 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1758 		/* This opens up the world of extra features. */
1759 		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1760 		if (csum)
1761 			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1762 
1763 		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1764 			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1765 				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
1766 		}
1767 		/* Individual feature bits: what can host handle? */
1768 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1769 			dev->hw_features |= NETIF_F_TSO;
1770 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1771 			dev->hw_features |= NETIF_F_TSO6;
1772 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1773 			dev->hw_features |= NETIF_F_TSO_ECN;
1774 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1775 			dev->hw_features |= NETIF_F_UFO;
1776 
1777 		dev->features |= NETIF_F_GSO_ROBUST;
1778 
1779 		if (gso)
1780 			dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1781 		/* (!csum && gso) case will be fixed by register_netdev() */
1782 	}
1783 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
1784 		dev->features |= NETIF_F_RXCSUM;
1785 
1786 	dev->vlan_features = dev->features;
1787 
1788 	/* Configuration may specify what MAC to use.  Otherwise random. */
1789 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
1790 		virtio_cread_bytes(vdev,
1791 				   offsetof(struct virtio_net_config, mac),
1792 				   dev->dev_addr, dev->addr_len);
1793 	else
1794 		eth_hw_addr_random(dev);
1795 
1796 	/* Set up our device-specific information */
1797 	vi = netdev_priv(dev);
1798 	vi->dev = dev;
1799 	vi->vdev = vdev;
1800 	vdev->priv = vi;
1801 	vi->stats = alloc_percpu(struct virtnet_stats);
1802 	err = -ENOMEM;
1803 	if (vi->stats == NULL)
1804 		goto free;
1805 
1806 	for_each_possible_cpu(i) {
1807 		struct virtnet_stats *virtnet_stats;
1808 		virtnet_stats = per_cpu_ptr(vi->stats, i);
1809 		u64_stats_init(&virtnet_stats->tx_syncp);
1810 		u64_stats_init(&virtnet_stats->rx_syncp);
1811 	}
1812 
1813 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1814 
1815 	/* If we can receive ANY GSO packets, we must allocate large ones. */
1816 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1817 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1818 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
1819 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
1820 		vi->big_packets = true;
1821 
1822 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1823 		vi->mergeable_rx_bufs = true;
1824 
1825 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF) ||
1826 	    virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
1827 		vi->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
1828 	else
1829 		vi->hdr_len = sizeof(struct virtio_net_hdr);
1830 
1831 	if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT))
1832 		vi->any_header_sg = true;
1833 
1834 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1835 		vi->has_cvq = true;
1836 
1837 	if (vi->any_header_sg)
1838 		dev->needed_headroom = vi->hdr_len;
1839 
1840 	/* Use single tx/rx queue pair as default */
1841 	vi->curr_queue_pairs = 1;
1842 	vi->max_queue_pairs = max_queue_pairs;
1843 
1844 	/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1845 	err = init_vqs(vi);
1846 	if (err)
1847 		goto free_stats;
1848 
1849 #ifdef CONFIG_SYSFS
1850 	if (vi->mergeable_rx_bufs)
1851 		dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
1852 #endif
1853 	netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
1854 	netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
1855 
1856 	err = register_netdev(dev);
1857 	if (err) {
1858 		pr_debug("virtio_net: registering device failed\n");
1859 		goto free_vqs;
1860 	}
1861 
1862 	virtio_device_ready(vdev);
1863 
1864 	/* Last of all, set up some receive buffers. */
1865 	for (i = 0; i < vi->curr_queue_pairs; i++) {
1866 		try_fill_recv(vi, &vi->rq[i], GFP_KERNEL);
1867 
1868 		/* If we didn't even get one input buffer, we're useless. */
1869 		if (vi->rq[i].vq->num_free ==
1870 		    virtqueue_get_vring_size(vi->rq[i].vq)) {
1871 			free_unused_bufs(vi);
1872 			err = -ENOMEM;
1873 			goto free_recv_bufs;
1874 		}
1875 	}
1876 
1877 	vi->nb.notifier_call = &virtnet_cpu_callback;
1878 	err = register_hotcpu_notifier(&vi->nb);
1879 	if (err) {
1880 		pr_debug("virtio_net: registering cpu notifier failed\n");
1881 		goto free_recv_bufs;
1882 	}
1883 
1884 	/* Assume link up if device can't report link status,
1885 	   otherwise get link status from config. */
1886 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1887 		netif_carrier_off(dev);
1888 		schedule_work(&vi->config_work);
1889 	} else {
1890 		vi->status = VIRTIO_NET_S_LINK_UP;
1891 		netif_carrier_on(dev);
1892 	}
1893 
1894 	pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1895 		 dev->name, max_queue_pairs);
1896 
1897 	return 0;
1898 
1899 free_recv_bufs:
1900 	vi->vdev->config->reset(vdev);
1901 
1902 	free_receive_bufs(vi);
1903 	unregister_netdev(dev);
1904 free_vqs:
1905 	cancel_delayed_work_sync(&vi->refill);
1906 	free_receive_page_frags(vi);
1907 	virtnet_del_vqs(vi);
1908 free_stats:
1909 	free_percpu(vi->stats);
1910 free:
1911 	free_netdev(dev);
1912 	return err;
1913 }
1914 
1915 static void remove_vq_common(struct virtnet_info *vi)
1916 {
1917 	vi->vdev->config->reset(vi->vdev);
1918 
1919 	/* Free unused buffers in both send and recv, if any. */
1920 	free_unused_bufs(vi);
1921 
1922 	free_receive_bufs(vi);
1923 
1924 	free_receive_page_frags(vi);
1925 
1926 	virtnet_del_vqs(vi);
1927 }
1928 
1929 static void virtnet_remove(struct virtio_device *vdev)
1930 {
1931 	struct virtnet_info *vi = vdev->priv;
1932 
1933 	unregister_hotcpu_notifier(&vi->nb);
1934 
1935 	/* Make sure no work handler is accessing the device. */
1936 	flush_work(&vi->config_work);
1937 
1938 	unregister_netdev(vi->dev);
1939 
1940 	remove_vq_common(vi);
1941 
1942 	free_percpu(vi->stats);
1943 	free_netdev(vi->dev);
1944 }
1945 
1946 #ifdef CONFIG_PM_SLEEP
1947 static int virtnet_freeze(struct virtio_device *vdev)
1948 {
1949 	struct virtnet_info *vi = vdev->priv;
1950 	int i;
1951 
1952 	unregister_hotcpu_notifier(&vi->nb);
1953 
1954 	/* Make sure no work handler is accessing the device */
1955 	flush_work(&vi->config_work);
1956 
1957 	netif_device_detach(vi->dev);
1958 	cancel_delayed_work_sync(&vi->refill);
1959 
1960 	if (netif_running(vi->dev)) {
1961 		for (i = 0; i < vi->max_queue_pairs; i++)
1962 			napi_disable(&vi->rq[i].napi);
1963 	}
1964 
1965 	remove_vq_common(vi);
1966 
1967 	return 0;
1968 }
1969 
1970 static int virtnet_restore(struct virtio_device *vdev)
1971 {
1972 	struct virtnet_info *vi = vdev->priv;
1973 	int err, i;
1974 
1975 	err = init_vqs(vi);
1976 	if (err)
1977 		return err;
1978 
1979 	virtio_device_ready(vdev);
1980 
1981 	if (netif_running(vi->dev)) {
1982 		for (i = 0; i < vi->curr_queue_pairs; i++)
1983 			if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
1984 				schedule_delayed_work(&vi->refill, 0);
1985 
1986 		for (i = 0; i < vi->max_queue_pairs; i++)
1987 			virtnet_napi_enable(&vi->rq[i]);
1988 	}
1989 
1990 	netif_device_attach(vi->dev);
1991 
1992 	rtnl_lock();
1993 	virtnet_set_queues(vi, vi->curr_queue_pairs);
1994 	rtnl_unlock();
1995 
1996 	err = register_hotcpu_notifier(&vi->nb);
1997 	if (err)
1998 		return err;
1999 
2000 	return 0;
2001 }
2002 #endif
2003 
2004 static struct virtio_device_id id_table[] = {
2005 	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
2006 	{ 0 },
2007 };
2008 
2009 static unsigned int features[] = {
2010 	VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
2011 	VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
2012 	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
2013 	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
2014 	VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
2015 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
2016 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
2017 	VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
2018 	VIRTIO_NET_F_CTRL_MAC_ADDR,
2019 	VIRTIO_F_ANY_LAYOUT,
2020 };
2021 
2022 static struct virtio_driver virtio_net_driver = {
2023 	.feature_table = features,
2024 	.feature_table_size = ARRAY_SIZE(features),
2025 	.driver.name =	KBUILD_MODNAME,
2026 	.driver.owner =	THIS_MODULE,
2027 	.id_table =	id_table,
2028 	.probe =	virtnet_probe,
2029 	.remove =	virtnet_remove,
2030 	.config_changed = virtnet_config_changed,
2031 #ifdef CONFIG_PM_SLEEP
2032 	.freeze =	virtnet_freeze,
2033 	.restore =	virtnet_restore,
2034 #endif
2035 };
2036 
2037 module_virtio_driver(virtio_net_driver);
2038 
2039 MODULE_DEVICE_TABLE(virtio, id_table);
2040 MODULE_DESCRIPTION("Virtio network driver");
2041 MODULE_LICENSE("GPL");
2042