xref: /openbmc/linux/drivers/net/virtio_net.c (revision c819e2cf)
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 		{
494 			static bool warned;
495 
496 			if (!warned) {
497 				warned = true;
498 				netdev_warn(dev,
499 					    "host using disabled UFO feature; please fix it\n");
500 			}
501 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
502 			break;
503 		}
504 		case VIRTIO_NET_HDR_GSO_TCPV6:
505 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
506 			break;
507 		default:
508 			net_warn_ratelimited("%s: bad gso type %u.\n",
509 					     dev->name, hdr->hdr.gso_type);
510 			goto frame_err;
511 		}
512 
513 		if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
514 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
515 
516 		skb_shinfo(skb)->gso_size = virtio16_to_cpu(vi->vdev,
517 							    hdr->hdr.gso_size);
518 		if (skb_shinfo(skb)->gso_size == 0) {
519 			net_warn_ratelimited("%s: zero gso size.\n", dev->name);
520 			goto frame_err;
521 		}
522 
523 		/* Header must be checked, and gso_segs computed. */
524 		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
525 		skb_shinfo(skb)->gso_segs = 0;
526 	}
527 
528 	skb_mark_napi_id(skb, &rq->napi);
529 
530 	netif_receive_skb(skb);
531 	return;
532 
533 frame_err:
534 	dev->stats.rx_frame_errors++;
535 	dev_kfree_skb(skb);
536 }
537 
538 static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
539 			     gfp_t gfp)
540 {
541 	struct sk_buff *skb;
542 	struct virtio_net_hdr_mrg_rxbuf *hdr;
543 	int err;
544 
545 	skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
546 	if (unlikely(!skb))
547 		return -ENOMEM;
548 
549 	skb_put(skb, GOOD_PACKET_LEN);
550 
551 	hdr = skb_vnet_hdr(skb);
552 	sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
553 	sg_set_buf(rq->sg, hdr, vi->hdr_len);
554 	skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
555 
556 	err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
557 	if (err < 0)
558 		dev_kfree_skb(skb);
559 
560 	return err;
561 }
562 
563 static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
564 			   gfp_t gfp)
565 {
566 	struct page *first, *list = NULL;
567 	char *p;
568 	int i, err, offset;
569 
570 	sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
571 
572 	/* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
573 	for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
574 		first = get_a_page(rq, gfp);
575 		if (!first) {
576 			if (list)
577 				give_pages(rq, list);
578 			return -ENOMEM;
579 		}
580 		sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
581 
582 		/* chain new page in list head to match sg */
583 		first->private = (unsigned long)list;
584 		list = first;
585 	}
586 
587 	first = get_a_page(rq, gfp);
588 	if (!first) {
589 		give_pages(rq, list);
590 		return -ENOMEM;
591 	}
592 	p = page_address(first);
593 
594 	/* rq->sg[0], rq->sg[1] share the same page */
595 	/* a separated rq->sg[0] for header - required in case !any_header_sg */
596 	sg_set_buf(&rq->sg[0], p, vi->hdr_len);
597 
598 	/* rq->sg[1] for data packet, from offset */
599 	offset = sizeof(struct padded_vnet_hdr);
600 	sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
601 
602 	/* chain first in list head */
603 	first->private = (unsigned long)list;
604 	err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
605 				  first, gfp);
606 	if (err < 0)
607 		give_pages(rq, first);
608 
609 	return err;
610 }
611 
612 static unsigned int get_mergeable_buf_len(struct ewma *avg_pkt_len)
613 {
614 	const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
615 	unsigned int len;
616 
617 	len = hdr_len + clamp_t(unsigned int, ewma_read(avg_pkt_len),
618 			GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
619 	return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
620 }
621 
622 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
623 {
624 	struct page_frag *alloc_frag = &rq->alloc_frag;
625 	char *buf;
626 	unsigned long ctx;
627 	int err;
628 	unsigned int len, hole;
629 
630 	len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
631 	if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
632 		return -ENOMEM;
633 
634 	buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
635 	ctx = mergeable_buf_to_ctx(buf, len);
636 	get_page(alloc_frag->page);
637 	alloc_frag->offset += len;
638 	hole = alloc_frag->size - alloc_frag->offset;
639 	if (hole < len) {
640 		/* To avoid internal fragmentation, if there is very likely not
641 		 * enough space for another buffer, add the remaining space to
642 		 * the current buffer. This extra space is not included in
643 		 * the truesize stored in ctx.
644 		 */
645 		len += hole;
646 		alloc_frag->offset += hole;
647 	}
648 
649 	sg_init_one(rq->sg, buf, len);
650 	err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, (void *)ctx, gfp);
651 	if (err < 0)
652 		put_page(virt_to_head_page(buf));
653 
654 	return err;
655 }
656 
657 /*
658  * Returns false if we couldn't fill entirely (OOM).
659  *
660  * Normally run in the receive path, but can also be run from ndo_open
661  * before we're receiving packets, or from refill_work which is
662  * careful to disable receiving (using napi_disable).
663  */
664 static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
665 			  gfp_t gfp)
666 {
667 	int err;
668 	bool oom;
669 
670 	gfp |= __GFP_COLD;
671 	do {
672 		if (vi->mergeable_rx_bufs)
673 			err = add_recvbuf_mergeable(rq, gfp);
674 		else if (vi->big_packets)
675 			err = add_recvbuf_big(vi, rq, gfp);
676 		else
677 			err = add_recvbuf_small(vi, rq, gfp);
678 
679 		oom = err == -ENOMEM;
680 		if (err)
681 			break;
682 	} while (rq->vq->num_free);
683 	virtqueue_kick(rq->vq);
684 	return !oom;
685 }
686 
687 static void skb_recv_done(struct virtqueue *rvq)
688 {
689 	struct virtnet_info *vi = rvq->vdev->priv;
690 	struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
691 
692 	/* Schedule NAPI, Suppress further interrupts if successful. */
693 	if (napi_schedule_prep(&rq->napi)) {
694 		virtqueue_disable_cb(rvq);
695 		__napi_schedule(&rq->napi);
696 	}
697 }
698 
699 static void virtnet_napi_enable(struct receive_queue *rq)
700 {
701 	napi_enable(&rq->napi);
702 
703 	/* If all buffers were filled by other side before we napi_enabled, we
704 	 * won't get another interrupt, so process any outstanding packets
705 	 * now.  virtnet_poll wants re-enable the queue, so we disable here.
706 	 * We synchronize against interrupts via NAPI_STATE_SCHED */
707 	if (napi_schedule_prep(&rq->napi)) {
708 		virtqueue_disable_cb(rq->vq);
709 		local_bh_disable();
710 		__napi_schedule(&rq->napi);
711 		local_bh_enable();
712 	}
713 }
714 
715 static void refill_work(struct work_struct *work)
716 {
717 	struct virtnet_info *vi =
718 		container_of(work, struct virtnet_info, refill.work);
719 	bool still_empty;
720 	int i;
721 
722 	for (i = 0; i < vi->curr_queue_pairs; i++) {
723 		struct receive_queue *rq = &vi->rq[i];
724 
725 		napi_disable(&rq->napi);
726 		still_empty = !try_fill_recv(vi, rq, GFP_KERNEL);
727 		virtnet_napi_enable(rq);
728 
729 		/* In theory, this can happen: if we don't get any buffers in
730 		 * we will *never* try to fill again.
731 		 */
732 		if (still_empty)
733 			schedule_delayed_work(&vi->refill, HZ/2);
734 	}
735 }
736 
737 static int virtnet_receive(struct receive_queue *rq, int budget)
738 {
739 	struct virtnet_info *vi = rq->vq->vdev->priv;
740 	unsigned int len, received = 0;
741 	void *buf;
742 
743 	while (received < budget &&
744 	       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
745 		receive_buf(vi, rq, buf, len);
746 		received++;
747 	}
748 
749 	if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
750 		if (!try_fill_recv(vi, rq, GFP_ATOMIC))
751 			schedule_delayed_work(&vi->refill, 0);
752 	}
753 
754 	return received;
755 }
756 
757 static int virtnet_poll(struct napi_struct *napi, int budget)
758 {
759 	struct receive_queue *rq =
760 		container_of(napi, struct receive_queue, napi);
761 	unsigned int r, received = 0;
762 
763 	received += virtnet_receive(rq, budget - received);
764 
765 	/* Out of packets? */
766 	if (received < budget) {
767 		r = virtqueue_enable_cb_prepare(rq->vq);
768 		napi_complete(napi);
769 		if (unlikely(virtqueue_poll(rq->vq, r)) &&
770 		    napi_schedule_prep(napi)) {
771 			virtqueue_disable_cb(rq->vq);
772 			__napi_schedule(napi);
773 		}
774 	}
775 
776 	return received;
777 }
778 
779 #ifdef CONFIG_NET_RX_BUSY_POLL
780 /* must be called with local_bh_disable()d */
781 static int virtnet_busy_poll(struct napi_struct *napi)
782 {
783 	struct receive_queue *rq =
784 		container_of(napi, struct receive_queue, napi);
785 	struct virtnet_info *vi = rq->vq->vdev->priv;
786 	int r, received = 0, budget = 4;
787 
788 	if (!(vi->status & VIRTIO_NET_S_LINK_UP))
789 		return LL_FLUSH_FAILED;
790 
791 	if (!napi_schedule_prep(napi))
792 		return LL_FLUSH_BUSY;
793 
794 	virtqueue_disable_cb(rq->vq);
795 
796 again:
797 	received += virtnet_receive(rq, budget);
798 
799 	r = virtqueue_enable_cb_prepare(rq->vq);
800 	clear_bit(NAPI_STATE_SCHED, &napi->state);
801 	if (unlikely(virtqueue_poll(rq->vq, r)) &&
802 	    napi_schedule_prep(napi)) {
803 		virtqueue_disable_cb(rq->vq);
804 		if (received < budget) {
805 			budget -= received;
806 			goto again;
807 		} else {
808 			__napi_schedule(napi);
809 		}
810 	}
811 
812 	return received;
813 }
814 #endif	/* CONFIG_NET_RX_BUSY_POLL */
815 
816 static int virtnet_open(struct net_device *dev)
817 {
818 	struct virtnet_info *vi = netdev_priv(dev);
819 	int i;
820 
821 	for (i = 0; i < vi->max_queue_pairs; i++) {
822 		if (i < vi->curr_queue_pairs)
823 			/* Make sure we have some buffers: if oom use wq. */
824 			if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
825 				schedule_delayed_work(&vi->refill, 0);
826 		virtnet_napi_enable(&vi->rq[i]);
827 	}
828 
829 	return 0;
830 }
831 
832 static void free_old_xmit_skbs(struct send_queue *sq)
833 {
834 	struct sk_buff *skb;
835 	unsigned int len;
836 	struct virtnet_info *vi = sq->vq->vdev->priv;
837 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
838 
839 	while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
840 		pr_debug("Sent skb %p\n", skb);
841 
842 		u64_stats_update_begin(&stats->tx_syncp);
843 		stats->tx_bytes += skb->len;
844 		stats->tx_packets++;
845 		u64_stats_update_end(&stats->tx_syncp);
846 
847 		dev_kfree_skb_any(skb);
848 	}
849 }
850 
851 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
852 {
853 	struct virtio_net_hdr_mrg_rxbuf *hdr;
854 	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
855 	struct virtnet_info *vi = sq->vq->vdev->priv;
856 	unsigned num_sg;
857 	unsigned hdr_len = vi->hdr_len;
858 	bool can_push;
859 
860 	pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
861 
862 	can_push = vi->any_header_sg &&
863 		!((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
864 		!skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
865 	/* Even if we can, don't push here yet as this would skew
866 	 * csum_start offset below. */
867 	if (can_push)
868 		hdr = (struct virtio_net_hdr_mrg_rxbuf *)(skb->data - hdr_len);
869 	else
870 		hdr = skb_vnet_hdr(skb);
871 
872 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
873 		hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
874 		hdr->hdr.csum_start = cpu_to_virtio16(vi->vdev,
875 						skb_checksum_start_offset(skb));
876 		hdr->hdr.csum_offset = cpu_to_virtio16(vi->vdev,
877 							 skb->csum_offset);
878 	} else {
879 		hdr->hdr.flags = 0;
880 		hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
881 	}
882 
883 	if (skb_is_gso(skb)) {
884 		hdr->hdr.hdr_len = cpu_to_virtio16(vi->vdev, skb_headlen(skb));
885 		hdr->hdr.gso_size = cpu_to_virtio16(vi->vdev,
886 						    skb_shinfo(skb)->gso_size);
887 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
888 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
889 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
890 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
891 		else
892 			BUG();
893 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
894 			hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
895 	} else {
896 		hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
897 		hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
898 	}
899 
900 	if (vi->mergeable_rx_bufs)
901 		hdr->num_buffers = 0;
902 
903 	sg_init_table(sq->sg, MAX_SKB_FRAGS + 2);
904 	if (can_push) {
905 		__skb_push(skb, hdr_len);
906 		num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
907 		/* Pull header back to avoid skew in tx bytes calculations. */
908 		__skb_pull(skb, hdr_len);
909 	} else {
910 		sg_set_buf(sq->sg, hdr, hdr_len);
911 		num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
912 	}
913 	return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
914 }
915 
916 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
917 {
918 	struct virtnet_info *vi = netdev_priv(dev);
919 	int qnum = skb_get_queue_mapping(skb);
920 	struct send_queue *sq = &vi->sq[qnum];
921 	int err;
922 	struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
923 	bool kick = !skb->xmit_more;
924 
925 	/* Free up any pending old buffers before queueing new ones. */
926 	free_old_xmit_skbs(sq);
927 
928 	/* Try to transmit */
929 	err = xmit_skb(sq, skb);
930 
931 	/* This should not happen! */
932 	if (unlikely(err)) {
933 		dev->stats.tx_fifo_errors++;
934 		if (net_ratelimit())
935 			dev_warn(&dev->dev,
936 				 "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
937 		dev->stats.tx_dropped++;
938 		dev_kfree_skb_any(skb);
939 		return NETDEV_TX_OK;
940 	}
941 
942 	/* Don't wait up for transmitted skbs to be freed. */
943 	skb_orphan(skb);
944 	nf_reset(skb);
945 
946 	/* Apparently nice girls don't return TX_BUSY; stop the queue
947 	 * before it gets out of hand.  Naturally, this wastes entries. */
948 	if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
949 		netif_stop_subqueue(dev, qnum);
950 		if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
951 			/* More just got used, free them then recheck. */
952 			free_old_xmit_skbs(sq);
953 			if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
954 				netif_start_subqueue(dev, qnum);
955 				virtqueue_disable_cb(sq->vq);
956 			}
957 		}
958 	}
959 
960 	if (kick || netif_xmit_stopped(txq))
961 		virtqueue_kick(sq->vq);
962 
963 	return NETDEV_TX_OK;
964 }
965 
966 /*
967  * Send command via the control virtqueue and check status.  Commands
968  * supported by the hypervisor, as indicated by feature bits, should
969  * never fail unless improperly formatted.
970  */
971 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
972 				 struct scatterlist *out)
973 {
974 	struct scatterlist *sgs[4], hdr, stat;
975 	struct virtio_net_ctrl_hdr ctrl;
976 	virtio_net_ctrl_ack status = ~0;
977 	unsigned out_num = 0, tmp;
978 
979 	/* Caller should know better */
980 	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
981 
982 	ctrl.class = class;
983 	ctrl.cmd = cmd;
984 	/* Add header */
985 	sg_init_one(&hdr, &ctrl, sizeof(ctrl));
986 	sgs[out_num++] = &hdr;
987 
988 	if (out)
989 		sgs[out_num++] = out;
990 
991 	/* Add return status. */
992 	sg_init_one(&stat, &status, sizeof(status));
993 	sgs[out_num] = &stat;
994 
995 	BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
996 	virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
997 
998 	if (unlikely(!virtqueue_kick(vi->cvq)))
999 		return status == VIRTIO_NET_OK;
1000 
1001 	/* Spin for a response, the kick causes an ioport write, trapping
1002 	 * into the hypervisor, so the request should be handled immediately.
1003 	 */
1004 	while (!virtqueue_get_buf(vi->cvq, &tmp) &&
1005 	       !virtqueue_is_broken(vi->cvq))
1006 		cpu_relax();
1007 
1008 	return status == VIRTIO_NET_OK;
1009 }
1010 
1011 static int virtnet_set_mac_address(struct net_device *dev, void *p)
1012 {
1013 	struct virtnet_info *vi = netdev_priv(dev);
1014 	struct virtio_device *vdev = vi->vdev;
1015 	int ret;
1016 	struct sockaddr *addr = p;
1017 	struct scatterlist sg;
1018 
1019 	ret = eth_prepare_mac_addr_change(dev, p);
1020 	if (ret)
1021 		return ret;
1022 
1023 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
1024 		sg_init_one(&sg, addr->sa_data, dev->addr_len);
1025 		if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1026 					  VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
1027 			dev_warn(&vdev->dev,
1028 				 "Failed to set mac address by vq command.\n");
1029 			return -EINVAL;
1030 		}
1031 	} else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC) &&
1032 		   !virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1033 		unsigned int i;
1034 
1035 		/* Naturally, this has an atomicity problem. */
1036 		for (i = 0; i < dev->addr_len; i++)
1037 			virtio_cwrite8(vdev,
1038 				       offsetof(struct virtio_net_config, mac) +
1039 				       i, addr->sa_data[i]);
1040 	}
1041 
1042 	eth_commit_mac_addr_change(dev, p);
1043 
1044 	return 0;
1045 }
1046 
1047 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
1048 					       struct rtnl_link_stats64 *tot)
1049 {
1050 	struct virtnet_info *vi = netdev_priv(dev);
1051 	int cpu;
1052 	unsigned int start;
1053 
1054 	for_each_possible_cpu(cpu) {
1055 		struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
1056 		u64 tpackets, tbytes, rpackets, rbytes;
1057 
1058 		do {
1059 			start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
1060 			tpackets = stats->tx_packets;
1061 			tbytes   = stats->tx_bytes;
1062 		} while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
1063 
1064 		do {
1065 			start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
1066 			rpackets = stats->rx_packets;
1067 			rbytes   = stats->rx_bytes;
1068 		} while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
1069 
1070 		tot->rx_packets += rpackets;
1071 		tot->tx_packets += tpackets;
1072 		tot->rx_bytes   += rbytes;
1073 		tot->tx_bytes   += tbytes;
1074 	}
1075 
1076 	tot->tx_dropped = dev->stats.tx_dropped;
1077 	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
1078 	tot->rx_dropped = dev->stats.rx_dropped;
1079 	tot->rx_length_errors = dev->stats.rx_length_errors;
1080 	tot->rx_frame_errors = dev->stats.rx_frame_errors;
1081 
1082 	return tot;
1083 }
1084 
1085 #ifdef CONFIG_NET_POLL_CONTROLLER
1086 static void virtnet_netpoll(struct net_device *dev)
1087 {
1088 	struct virtnet_info *vi = netdev_priv(dev);
1089 	int i;
1090 
1091 	for (i = 0; i < vi->curr_queue_pairs; i++)
1092 		napi_schedule(&vi->rq[i].napi);
1093 }
1094 #endif
1095 
1096 static void virtnet_ack_link_announce(struct virtnet_info *vi)
1097 {
1098 	rtnl_lock();
1099 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
1100 				  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
1101 		dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
1102 	rtnl_unlock();
1103 }
1104 
1105 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
1106 {
1107 	struct scatterlist sg;
1108 	struct virtio_net_ctrl_mq s;
1109 	struct net_device *dev = vi->dev;
1110 
1111 	if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
1112 		return 0;
1113 
1114 	s.virtqueue_pairs = cpu_to_virtio16(vi->vdev, queue_pairs);
1115 	sg_init_one(&sg, &s, sizeof(s));
1116 
1117 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
1118 				  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
1119 		dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
1120 			 queue_pairs);
1121 		return -EINVAL;
1122 	} else {
1123 		vi->curr_queue_pairs = queue_pairs;
1124 		/* virtnet_open() will refill when device is going to up. */
1125 		if (dev->flags & IFF_UP)
1126 			schedule_delayed_work(&vi->refill, 0);
1127 	}
1128 
1129 	return 0;
1130 }
1131 
1132 static int virtnet_close(struct net_device *dev)
1133 {
1134 	struct virtnet_info *vi = netdev_priv(dev);
1135 	int i;
1136 
1137 	/* Make sure refill_work doesn't re-enable napi! */
1138 	cancel_delayed_work_sync(&vi->refill);
1139 
1140 	for (i = 0; i < vi->max_queue_pairs; i++)
1141 		napi_disable(&vi->rq[i].napi);
1142 
1143 	return 0;
1144 }
1145 
1146 static void virtnet_set_rx_mode(struct net_device *dev)
1147 {
1148 	struct virtnet_info *vi = netdev_priv(dev);
1149 	struct scatterlist sg[2];
1150 	u8 promisc, allmulti;
1151 	struct virtio_net_ctrl_mac *mac_data;
1152 	struct netdev_hw_addr *ha;
1153 	int uc_count;
1154 	int mc_count;
1155 	void *buf;
1156 	int i;
1157 
1158 	/* We can't dynamically set ndo_set_rx_mode, so return gracefully */
1159 	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
1160 		return;
1161 
1162 	promisc = ((dev->flags & IFF_PROMISC) != 0);
1163 	allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
1164 
1165 	sg_init_one(sg, &promisc, sizeof(promisc));
1166 
1167 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1168 				  VIRTIO_NET_CTRL_RX_PROMISC, sg))
1169 		dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
1170 			 promisc ? "en" : "dis");
1171 
1172 	sg_init_one(sg, &allmulti, sizeof(allmulti));
1173 
1174 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1175 				  VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
1176 		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
1177 			 allmulti ? "en" : "dis");
1178 
1179 	uc_count = netdev_uc_count(dev);
1180 	mc_count = netdev_mc_count(dev);
1181 	/* MAC filter - use one buffer for both lists */
1182 	buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
1183 		      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
1184 	mac_data = buf;
1185 	if (!buf)
1186 		return;
1187 
1188 	sg_init_table(sg, 2);
1189 
1190 	/* Store the unicast list and count in the front of the buffer */
1191 	mac_data->entries = cpu_to_virtio32(vi->vdev, uc_count);
1192 	i = 0;
1193 	netdev_for_each_uc_addr(ha, dev)
1194 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1195 
1196 	sg_set_buf(&sg[0], mac_data,
1197 		   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
1198 
1199 	/* multicast list and count fill the end */
1200 	mac_data = (void *)&mac_data->macs[uc_count][0];
1201 
1202 	mac_data->entries = cpu_to_virtio32(vi->vdev, mc_count);
1203 	i = 0;
1204 	netdev_for_each_mc_addr(ha, dev)
1205 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1206 
1207 	sg_set_buf(&sg[1], mac_data,
1208 		   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1209 
1210 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1211 				  VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
1212 		dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
1213 
1214 	kfree(buf);
1215 }
1216 
1217 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1218 				   __be16 proto, u16 vid)
1219 {
1220 	struct virtnet_info *vi = netdev_priv(dev);
1221 	struct scatterlist sg;
1222 
1223 	sg_init_one(&sg, &vid, sizeof(vid));
1224 
1225 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1226 				  VIRTIO_NET_CTRL_VLAN_ADD, &sg))
1227 		dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1228 	return 0;
1229 }
1230 
1231 static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1232 				    __be16 proto, u16 vid)
1233 {
1234 	struct virtnet_info *vi = netdev_priv(dev);
1235 	struct scatterlist sg;
1236 
1237 	sg_init_one(&sg, &vid, sizeof(vid));
1238 
1239 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1240 				  VIRTIO_NET_CTRL_VLAN_DEL, &sg))
1241 		dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1242 	return 0;
1243 }
1244 
1245 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1246 {
1247 	int i;
1248 
1249 	if (vi->affinity_hint_set) {
1250 		for (i = 0; i < vi->max_queue_pairs; i++) {
1251 			virtqueue_set_affinity(vi->rq[i].vq, -1);
1252 			virtqueue_set_affinity(vi->sq[i].vq, -1);
1253 		}
1254 
1255 		vi->affinity_hint_set = false;
1256 	}
1257 }
1258 
1259 static void virtnet_set_affinity(struct virtnet_info *vi)
1260 {
1261 	int i;
1262 	int cpu;
1263 
1264 	/* In multiqueue mode, when the number of cpu is equal to the number of
1265 	 * queue pairs, we let the queue pairs to be private to one cpu by
1266 	 * setting the affinity hint to eliminate the contention.
1267 	 */
1268 	if (vi->curr_queue_pairs == 1 ||
1269 	    vi->max_queue_pairs != num_online_cpus()) {
1270 		virtnet_clean_affinity(vi, -1);
1271 		return;
1272 	}
1273 
1274 	i = 0;
1275 	for_each_online_cpu(cpu) {
1276 		virtqueue_set_affinity(vi->rq[i].vq, cpu);
1277 		virtqueue_set_affinity(vi->sq[i].vq, cpu);
1278 		netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
1279 		i++;
1280 	}
1281 
1282 	vi->affinity_hint_set = true;
1283 }
1284 
1285 static int virtnet_cpu_callback(struct notifier_block *nfb,
1286 			        unsigned long action, void *hcpu)
1287 {
1288 	struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1289 
1290 	switch(action & ~CPU_TASKS_FROZEN) {
1291 	case CPU_ONLINE:
1292 	case CPU_DOWN_FAILED:
1293 	case CPU_DEAD:
1294 		virtnet_set_affinity(vi);
1295 		break;
1296 	case CPU_DOWN_PREPARE:
1297 		virtnet_clean_affinity(vi, (long)hcpu);
1298 		break;
1299 	default:
1300 		break;
1301 	}
1302 
1303 	return NOTIFY_OK;
1304 }
1305 
1306 static void virtnet_get_ringparam(struct net_device *dev,
1307 				struct ethtool_ringparam *ring)
1308 {
1309 	struct virtnet_info *vi = netdev_priv(dev);
1310 
1311 	ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1312 	ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1313 	ring->rx_pending = ring->rx_max_pending;
1314 	ring->tx_pending = ring->tx_max_pending;
1315 }
1316 
1317 
1318 static void virtnet_get_drvinfo(struct net_device *dev,
1319 				struct ethtool_drvinfo *info)
1320 {
1321 	struct virtnet_info *vi = netdev_priv(dev);
1322 	struct virtio_device *vdev = vi->vdev;
1323 
1324 	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1325 	strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1326 	strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1327 
1328 }
1329 
1330 /* TODO: Eliminate OOO packets during switching */
1331 static int virtnet_set_channels(struct net_device *dev,
1332 				struct ethtool_channels *channels)
1333 {
1334 	struct virtnet_info *vi = netdev_priv(dev);
1335 	u16 queue_pairs = channels->combined_count;
1336 	int err;
1337 
1338 	/* We don't support separate rx/tx channels.
1339 	 * We don't allow setting 'other' channels.
1340 	 */
1341 	if (channels->rx_count || channels->tx_count || channels->other_count)
1342 		return -EINVAL;
1343 
1344 	if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
1345 		return -EINVAL;
1346 
1347 	get_online_cpus();
1348 	err = virtnet_set_queues(vi, queue_pairs);
1349 	if (!err) {
1350 		netif_set_real_num_tx_queues(dev, queue_pairs);
1351 		netif_set_real_num_rx_queues(dev, queue_pairs);
1352 
1353 		virtnet_set_affinity(vi);
1354 	}
1355 	put_online_cpus();
1356 
1357 	return err;
1358 }
1359 
1360 static void virtnet_get_channels(struct net_device *dev,
1361 				 struct ethtool_channels *channels)
1362 {
1363 	struct virtnet_info *vi = netdev_priv(dev);
1364 
1365 	channels->combined_count = vi->curr_queue_pairs;
1366 	channels->max_combined = vi->max_queue_pairs;
1367 	channels->max_other = 0;
1368 	channels->rx_count = 0;
1369 	channels->tx_count = 0;
1370 	channels->other_count = 0;
1371 }
1372 
1373 static const struct ethtool_ops virtnet_ethtool_ops = {
1374 	.get_drvinfo = virtnet_get_drvinfo,
1375 	.get_link = ethtool_op_get_link,
1376 	.get_ringparam = virtnet_get_ringparam,
1377 	.set_channels = virtnet_set_channels,
1378 	.get_channels = virtnet_get_channels,
1379 };
1380 
1381 #define MIN_MTU 68
1382 #define MAX_MTU 65535
1383 
1384 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1385 {
1386 	if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1387 		return -EINVAL;
1388 	dev->mtu = new_mtu;
1389 	return 0;
1390 }
1391 
1392 static const struct net_device_ops virtnet_netdev = {
1393 	.ndo_open            = virtnet_open,
1394 	.ndo_stop   	     = virtnet_close,
1395 	.ndo_start_xmit      = start_xmit,
1396 	.ndo_validate_addr   = eth_validate_addr,
1397 	.ndo_set_mac_address = virtnet_set_mac_address,
1398 	.ndo_set_rx_mode     = virtnet_set_rx_mode,
1399 	.ndo_change_mtu	     = virtnet_change_mtu,
1400 	.ndo_get_stats64     = virtnet_stats,
1401 	.ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1402 	.ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1403 #ifdef CONFIG_NET_POLL_CONTROLLER
1404 	.ndo_poll_controller = virtnet_netpoll,
1405 #endif
1406 #ifdef CONFIG_NET_RX_BUSY_POLL
1407 	.ndo_busy_poll		= virtnet_busy_poll,
1408 #endif
1409 };
1410 
1411 static void virtnet_config_changed_work(struct work_struct *work)
1412 {
1413 	struct virtnet_info *vi =
1414 		container_of(work, struct virtnet_info, config_work);
1415 	u16 v;
1416 
1417 	if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
1418 				 struct virtio_net_config, status, &v) < 0)
1419 		return;
1420 
1421 	if (v & VIRTIO_NET_S_ANNOUNCE) {
1422 		netdev_notify_peers(vi->dev);
1423 		virtnet_ack_link_announce(vi);
1424 	}
1425 
1426 	/* Ignore unknown (future) status bits */
1427 	v &= VIRTIO_NET_S_LINK_UP;
1428 
1429 	if (vi->status == v)
1430 		return;
1431 
1432 	vi->status = v;
1433 
1434 	if (vi->status & VIRTIO_NET_S_LINK_UP) {
1435 		netif_carrier_on(vi->dev);
1436 		netif_tx_wake_all_queues(vi->dev);
1437 	} else {
1438 		netif_carrier_off(vi->dev);
1439 		netif_tx_stop_all_queues(vi->dev);
1440 	}
1441 }
1442 
1443 static void virtnet_config_changed(struct virtio_device *vdev)
1444 {
1445 	struct virtnet_info *vi = vdev->priv;
1446 
1447 	schedule_work(&vi->config_work);
1448 }
1449 
1450 static void virtnet_free_queues(struct virtnet_info *vi)
1451 {
1452 	int i;
1453 
1454 	for (i = 0; i < vi->max_queue_pairs; i++)
1455 		netif_napi_del(&vi->rq[i].napi);
1456 
1457 	kfree(vi->rq);
1458 	kfree(vi->sq);
1459 }
1460 
1461 static void free_receive_bufs(struct virtnet_info *vi)
1462 {
1463 	int i;
1464 
1465 	for (i = 0; i < vi->max_queue_pairs; i++) {
1466 		while (vi->rq[i].pages)
1467 			__free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1468 	}
1469 }
1470 
1471 static void free_receive_page_frags(struct virtnet_info *vi)
1472 {
1473 	int i;
1474 	for (i = 0; i < vi->max_queue_pairs; i++)
1475 		if (vi->rq[i].alloc_frag.page)
1476 			put_page(vi->rq[i].alloc_frag.page);
1477 }
1478 
1479 static void free_unused_bufs(struct virtnet_info *vi)
1480 {
1481 	void *buf;
1482 	int i;
1483 
1484 	for (i = 0; i < vi->max_queue_pairs; i++) {
1485 		struct virtqueue *vq = vi->sq[i].vq;
1486 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1487 			dev_kfree_skb(buf);
1488 	}
1489 
1490 	for (i = 0; i < vi->max_queue_pairs; i++) {
1491 		struct virtqueue *vq = vi->rq[i].vq;
1492 
1493 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1494 			if (vi->mergeable_rx_bufs) {
1495 				unsigned long ctx = (unsigned long)buf;
1496 				void *base = mergeable_ctx_to_buf_address(ctx);
1497 				put_page(virt_to_head_page(base));
1498 			} else if (vi->big_packets) {
1499 				give_pages(&vi->rq[i], buf);
1500 			} else {
1501 				dev_kfree_skb(buf);
1502 			}
1503 		}
1504 	}
1505 }
1506 
1507 static void virtnet_del_vqs(struct virtnet_info *vi)
1508 {
1509 	struct virtio_device *vdev = vi->vdev;
1510 
1511 	virtnet_clean_affinity(vi, -1);
1512 
1513 	vdev->config->del_vqs(vdev);
1514 
1515 	virtnet_free_queues(vi);
1516 }
1517 
1518 static int virtnet_find_vqs(struct virtnet_info *vi)
1519 {
1520 	vq_callback_t **callbacks;
1521 	struct virtqueue **vqs;
1522 	int ret = -ENOMEM;
1523 	int i, total_vqs;
1524 	const char **names;
1525 
1526 	/* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1527 	 * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1528 	 * possible control vq.
1529 	 */
1530 	total_vqs = vi->max_queue_pairs * 2 +
1531 		    virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1532 
1533 	/* Allocate space for find_vqs parameters */
1534 	vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1535 	if (!vqs)
1536 		goto err_vq;
1537 	callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1538 	if (!callbacks)
1539 		goto err_callback;
1540 	names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1541 	if (!names)
1542 		goto err_names;
1543 
1544 	/* Parameters for control virtqueue, if any */
1545 	if (vi->has_cvq) {
1546 		callbacks[total_vqs - 1] = NULL;
1547 		names[total_vqs - 1] = "control";
1548 	}
1549 
1550 	/* Allocate/initialize parameters for send/receive virtqueues */
1551 	for (i = 0; i < vi->max_queue_pairs; i++) {
1552 		callbacks[rxq2vq(i)] = skb_recv_done;
1553 		callbacks[txq2vq(i)] = skb_xmit_done;
1554 		sprintf(vi->rq[i].name, "input.%d", i);
1555 		sprintf(vi->sq[i].name, "output.%d", i);
1556 		names[rxq2vq(i)] = vi->rq[i].name;
1557 		names[txq2vq(i)] = vi->sq[i].name;
1558 	}
1559 
1560 	ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1561 					 names);
1562 	if (ret)
1563 		goto err_find;
1564 
1565 	if (vi->has_cvq) {
1566 		vi->cvq = vqs[total_vqs - 1];
1567 		if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1568 			vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1569 	}
1570 
1571 	for (i = 0; i < vi->max_queue_pairs; i++) {
1572 		vi->rq[i].vq = vqs[rxq2vq(i)];
1573 		vi->sq[i].vq = vqs[txq2vq(i)];
1574 	}
1575 
1576 	kfree(names);
1577 	kfree(callbacks);
1578 	kfree(vqs);
1579 
1580 	return 0;
1581 
1582 err_find:
1583 	kfree(names);
1584 err_names:
1585 	kfree(callbacks);
1586 err_callback:
1587 	kfree(vqs);
1588 err_vq:
1589 	return ret;
1590 }
1591 
1592 static int virtnet_alloc_queues(struct virtnet_info *vi)
1593 {
1594 	int i;
1595 
1596 	vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1597 	if (!vi->sq)
1598 		goto err_sq;
1599 	vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1600 	if (!vi->rq)
1601 		goto err_rq;
1602 
1603 	INIT_DELAYED_WORK(&vi->refill, refill_work);
1604 	for (i = 0; i < vi->max_queue_pairs; i++) {
1605 		vi->rq[i].pages = NULL;
1606 		netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1607 			       napi_weight);
1608 		napi_hash_add(&vi->rq[i].napi);
1609 
1610 		sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1611 		ewma_init(&vi->rq[i].mrg_avg_pkt_len, 1, RECEIVE_AVG_WEIGHT);
1612 		sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1613 	}
1614 
1615 	return 0;
1616 
1617 err_rq:
1618 	kfree(vi->sq);
1619 err_sq:
1620 	return -ENOMEM;
1621 }
1622 
1623 static int init_vqs(struct virtnet_info *vi)
1624 {
1625 	int ret;
1626 
1627 	/* Allocate send & receive queues */
1628 	ret = virtnet_alloc_queues(vi);
1629 	if (ret)
1630 		goto err;
1631 
1632 	ret = virtnet_find_vqs(vi);
1633 	if (ret)
1634 		goto err_free;
1635 
1636 	get_online_cpus();
1637 	virtnet_set_affinity(vi);
1638 	put_online_cpus();
1639 
1640 	return 0;
1641 
1642 err_free:
1643 	virtnet_free_queues(vi);
1644 err:
1645 	return ret;
1646 }
1647 
1648 #ifdef CONFIG_SYSFS
1649 static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
1650 		struct rx_queue_attribute *attribute, char *buf)
1651 {
1652 	struct virtnet_info *vi = netdev_priv(queue->dev);
1653 	unsigned int queue_index = get_netdev_rx_queue_index(queue);
1654 	struct ewma *avg;
1655 
1656 	BUG_ON(queue_index >= vi->max_queue_pairs);
1657 	avg = &vi->rq[queue_index].mrg_avg_pkt_len;
1658 	return sprintf(buf, "%u\n", get_mergeable_buf_len(avg));
1659 }
1660 
1661 static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
1662 	__ATTR_RO(mergeable_rx_buffer_size);
1663 
1664 static struct attribute *virtio_net_mrg_rx_attrs[] = {
1665 	&mergeable_rx_buffer_size_attribute.attr,
1666 	NULL
1667 };
1668 
1669 static const struct attribute_group virtio_net_mrg_rx_group = {
1670 	.name = "virtio_net",
1671 	.attrs = virtio_net_mrg_rx_attrs
1672 };
1673 #endif
1674 
1675 static bool virtnet_fail_on_feature(struct virtio_device *vdev,
1676 				    unsigned int fbit,
1677 				    const char *fname, const char *dname)
1678 {
1679 	if (!virtio_has_feature(vdev, fbit))
1680 		return false;
1681 
1682 	dev_err(&vdev->dev, "device advertises feature %s but not %s",
1683 		fname, dname);
1684 
1685 	return true;
1686 }
1687 
1688 #define VIRTNET_FAIL_ON(vdev, fbit, dbit)			\
1689 	virtnet_fail_on_feature(vdev, fbit, #fbit, dbit)
1690 
1691 static bool virtnet_validate_features(struct virtio_device *vdev)
1692 {
1693 	if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
1694 	    (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
1695 			     "VIRTIO_NET_F_CTRL_VQ") ||
1696 	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
1697 			     "VIRTIO_NET_F_CTRL_VQ") ||
1698 	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
1699 			     "VIRTIO_NET_F_CTRL_VQ") ||
1700 	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") ||
1701 	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
1702 			     "VIRTIO_NET_F_CTRL_VQ"))) {
1703 		return false;
1704 	}
1705 
1706 	return true;
1707 }
1708 
1709 static int virtnet_probe(struct virtio_device *vdev)
1710 {
1711 	int i, err;
1712 	struct net_device *dev;
1713 	struct virtnet_info *vi;
1714 	u16 max_queue_pairs;
1715 
1716 	if (!virtnet_validate_features(vdev))
1717 		return -EINVAL;
1718 
1719 	/* Find if host supports multiqueue virtio_net device */
1720 	err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
1721 				   struct virtio_net_config,
1722 				   max_virtqueue_pairs, &max_queue_pairs);
1723 
1724 	/* We need at least 2 queue's */
1725 	if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1726 	    max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1727 	    !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1728 		max_queue_pairs = 1;
1729 
1730 	/* Allocate ourselves a network device with room for our info */
1731 	dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1732 	if (!dev)
1733 		return -ENOMEM;
1734 
1735 	/* Set up network device as normal. */
1736 	dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1737 	dev->netdev_ops = &virtnet_netdev;
1738 	dev->features = NETIF_F_HIGHDMA;
1739 
1740 	dev->ethtool_ops = &virtnet_ethtool_ops;
1741 	SET_NETDEV_DEV(dev, &vdev->dev);
1742 
1743 	/* Do we support "hardware" checksums? */
1744 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1745 		/* This opens up the world of extra features. */
1746 		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1747 		if (csum)
1748 			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1749 
1750 		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1751 			dev->hw_features |= NETIF_F_TSO
1752 				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
1753 		}
1754 		/* Individual feature bits: what can host handle? */
1755 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1756 			dev->hw_features |= NETIF_F_TSO;
1757 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1758 			dev->hw_features |= NETIF_F_TSO6;
1759 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1760 			dev->hw_features |= NETIF_F_TSO_ECN;
1761 
1762 		if (gso)
1763 			dev->features |= dev->hw_features & NETIF_F_ALL_TSO;
1764 		/* (!csum && gso) case will be fixed by register_netdev() */
1765 	}
1766 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
1767 		dev->features |= NETIF_F_RXCSUM;
1768 
1769 	dev->vlan_features = dev->features;
1770 
1771 	/* Configuration may specify what MAC to use.  Otherwise random. */
1772 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
1773 		virtio_cread_bytes(vdev,
1774 				   offsetof(struct virtio_net_config, mac),
1775 				   dev->dev_addr, dev->addr_len);
1776 	else
1777 		eth_hw_addr_random(dev);
1778 
1779 	/* Set up our device-specific information */
1780 	vi = netdev_priv(dev);
1781 	vi->dev = dev;
1782 	vi->vdev = vdev;
1783 	vdev->priv = vi;
1784 	vi->stats = alloc_percpu(struct virtnet_stats);
1785 	err = -ENOMEM;
1786 	if (vi->stats == NULL)
1787 		goto free;
1788 
1789 	for_each_possible_cpu(i) {
1790 		struct virtnet_stats *virtnet_stats;
1791 		virtnet_stats = per_cpu_ptr(vi->stats, i);
1792 		u64_stats_init(&virtnet_stats->tx_syncp);
1793 		u64_stats_init(&virtnet_stats->rx_syncp);
1794 	}
1795 
1796 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1797 
1798 	/* If we can receive ANY GSO packets, we must allocate large ones. */
1799 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1800 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1801 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
1802 		vi->big_packets = true;
1803 
1804 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1805 		vi->mergeable_rx_bufs = true;
1806 
1807 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF) ||
1808 	    virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
1809 		vi->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
1810 	else
1811 		vi->hdr_len = sizeof(struct virtio_net_hdr);
1812 
1813 	if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT))
1814 		vi->any_header_sg = true;
1815 
1816 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1817 		vi->has_cvq = true;
1818 
1819 	if (vi->any_header_sg)
1820 		dev->needed_headroom = vi->hdr_len;
1821 
1822 	/* Use single tx/rx queue pair as default */
1823 	vi->curr_queue_pairs = 1;
1824 	vi->max_queue_pairs = max_queue_pairs;
1825 
1826 	/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1827 	err = init_vqs(vi);
1828 	if (err)
1829 		goto free_stats;
1830 
1831 #ifdef CONFIG_SYSFS
1832 	if (vi->mergeable_rx_bufs)
1833 		dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
1834 #endif
1835 	netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
1836 	netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
1837 
1838 	err = register_netdev(dev);
1839 	if (err) {
1840 		pr_debug("virtio_net: registering device failed\n");
1841 		goto free_vqs;
1842 	}
1843 
1844 	virtio_device_ready(vdev);
1845 
1846 	/* Last of all, set up some receive buffers. */
1847 	for (i = 0; i < vi->curr_queue_pairs; i++) {
1848 		try_fill_recv(vi, &vi->rq[i], GFP_KERNEL);
1849 
1850 		/* If we didn't even get one input buffer, we're useless. */
1851 		if (vi->rq[i].vq->num_free ==
1852 		    virtqueue_get_vring_size(vi->rq[i].vq)) {
1853 			free_unused_bufs(vi);
1854 			err = -ENOMEM;
1855 			goto free_recv_bufs;
1856 		}
1857 	}
1858 
1859 	vi->nb.notifier_call = &virtnet_cpu_callback;
1860 	err = register_hotcpu_notifier(&vi->nb);
1861 	if (err) {
1862 		pr_debug("virtio_net: registering cpu notifier failed\n");
1863 		goto free_recv_bufs;
1864 	}
1865 
1866 	/* Assume link up if device can't report link status,
1867 	   otherwise get link status from config. */
1868 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1869 		netif_carrier_off(dev);
1870 		schedule_work(&vi->config_work);
1871 	} else {
1872 		vi->status = VIRTIO_NET_S_LINK_UP;
1873 		netif_carrier_on(dev);
1874 	}
1875 
1876 	pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1877 		 dev->name, max_queue_pairs);
1878 
1879 	return 0;
1880 
1881 free_recv_bufs:
1882 	vi->vdev->config->reset(vdev);
1883 
1884 	free_receive_bufs(vi);
1885 	unregister_netdev(dev);
1886 free_vqs:
1887 	cancel_delayed_work_sync(&vi->refill);
1888 	free_receive_page_frags(vi);
1889 	virtnet_del_vqs(vi);
1890 free_stats:
1891 	free_percpu(vi->stats);
1892 free:
1893 	free_netdev(dev);
1894 	return err;
1895 }
1896 
1897 static void remove_vq_common(struct virtnet_info *vi)
1898 {
1899 	vi->vdev->config->reset(vi->vdev);
1900 
1901 	/* Free unused buffers in both send and recv, if any. */
1902 	free_unused_bufs(vi);
1903 
1904 	free_receive_bufs(vi);
1905 
1906 	free_receive_page_frags(vi);
1907 
1908 	virtnet_del_vqs(vi);
1909 }
1910 
1911 static void virtnet_remove(struct virtio_device *vdev)
1912 {
1913 	struct virtnet_info *vi = vdev->priv;
1914 
1915 	unregister_hotcpu_notifier(&vi->nb);
1916 
1917 	/* Make sure no work handler is accessing the device. */
1918 	flush_work(&vi->config_work);
1919 
1920 	unregister_netdev(vi->dev);
1921 
1922 	remove_vq_common(vi);
1923 
1924 	free_percpu(vi->stats);
1925 	free_netdev(vi->dev);
1926 }
1927 
1928 #ifdef CONFIG_PM_SLEEP
1929 static int virtnet_freeze(struct virtio_device *vdev)
1930 {
1931 	struct virtnet_info *vi = vdev->priv;
1932 	int i;
1933 
1934 	unregister_hotcpu_notifier(&vi->nb);
1935 
1936 	/* Make sure no work handler is accessing the device */
1937 	flush_work(&vi->config_work);
1938 
1939 	netif_device_detach(vi->dev);
1940 	cancel_delayed_work_sync(&vi->refill);
1941 
1942 	if (netif_running(vi->dev)) {
1943 		for (i = 0; i < vi->max_queue_pairs; i++) {
1944 			napi_disable(&vi->rq[i].napi);
1945 			napi_hash_del(&vi->rq[i].napi);
1946 			netif_napi_del(&vi->rq[i].napi);
1947 		}
1948 	}
1949 
1950 	remove_vq_common(vi);
1951 
1952 	return 0;
1953 }
1954 
1955 static int virtnet_restore(struct virtio_device *vdev)
1956 {
1957 	struct virtnet_info *vi = vdev->priv;
1958 	int err, i;
1959 
1960 	err = init_vqs(vi);
1961 	if (err)
1962 		return err;
1963 
1964 	virtio_device_ready(vdev);
1965 
1966 	if (netif_running(vi->dev)) {
1967 		for (i = 0; i < vi->curr_queue_pairs; i++)
1968 			if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
1969 				schedule_delayed_work(&vi->refill, 0);
1970 
1971 		for (i = 0; i < vi->max_queue_pairs; i++)
1972 			virtnet_napi_enable(&vi->rq[i]);
1973 	}
1974 
1975 	netif_device_attach(vi->dev);
1976 
1977 	rtnl_lock();
1978 	virtnet_set_queues(vi, vi->curr_queue_pairs);
1979 	rtnl_unlock();
1980 
1981 	err = register_hotcpu_notifier(&vi->nb);
1982 	if (err)
1983 		return err;
1984 
1985 	return 0;
1986 }
1987 #endif
1988 
1989 static struct virtio_device_id id_table[] = {
1990 	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1991 	{ 0 },
1992 };
1993 
1994 static unsigned int features[] = {
1995 	VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1996 	VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1997 	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_TSO6,
1998 	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1999 	VIRTIO_NET_F_GUEST_ECN,
2000 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
2001 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
2002 	VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
2003 	VIRTIO_NET_F_CTRL_MAC_ADDR,
2004 	VIRTIO_F_ANY_LAYOUT,
2005 };
2006 
2007 static struct virtio_driver virtio_net_driver = {
2008 	.feature_table = features,
2009 	.feature_table_size = ARRAY_SIZE(features),
2010 	.driver.name =	KBUILD_MODNAME,
2011 	.driver.owner =	THIS_MODULE,
2012 	.id_table =	id_table,
2013 	.probe =	virtnet_probe,
2014 	.remove =	virtnet_remove,
2015 	.config_changed = virtnet_config_changed,
2016 #ifdef CONFIG_PM_SLEEP
2017 	.freeze =	virtnet_freeze,
2018 	.restore =	virtnet_restore,
2019 #endif
2020 };
2021 
2022 module_virtio_driver(virtio_net_driver);
2023 
2024 MODULE_DEVICE_TABLE(virtio, id_table);
2025 MODULE_DESCRIPTION("Virtio network driver");
2026 MODULE_LICENSE("GPL");
2027