xref: /linux/drivers/net/hyperv/netvsc_drv.c (revision 3f2fb9a834cb1fcddbae22deca7fde136944dc89)
1 /*
2  * Copyright (c) 2009, Microsoft Corporation.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program; if not, see <http://www.gnu.org/licenses/>.
15  *
16  * Authors:
17  *   Haiyang Zhang <haiyangz@microsoft.com>
18  *   Hank Janssen  <hjanssen@microsoft.com>
19  */
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 
22 #include <linux/init.h>
23 #include <linux/atomic.h>
24 #include <linux/module.h>
25 #include <linux/highmem.h>
26 #include <linux/device.h>
27 #include <linux/io.h>
28 #include <linux/delay.h>
29 #include <linux/netdevice.h>
30 #include <linux/inetdevice.h>
31 #include <linux/etherdevice.h>
32 #include <linux/skbuff.h>
33 #include <linux/if_vlan.h>
34 #include <linux/in.h>
35 #include <linux/slab.h>
36 #include <net/arp.h>
37 #include <net/route.h>
38 #include <net/sock.h>
39 #include <net/pkt_sched.h>
40 
41 #include "hyperv_net.h"
42 
43 
44 #define RING_SIZE_MIN 64
45 #define LINKCHANGE_INT (2 * HZ)
46 #define NETVSC_HW_FEATURES	(NETIF_F_RXCSUM | \
47 				 NETIF_F_SG | \
48 				 NETIF_F_TSO | \
49 				 NETIF_F_TSO6 | \
50 				 NETIF_F_HW_CSUM)
51 static int ring_size = 128;
52 module_param(ring_size, int, S_IRUGO);
53 MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
54 
55 static int max_num_vrss_chns = 8;
56 
57 static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE |
58 				NETIF_MSG_LINK | NETIF_MSG_IFUP |
59 				NETIF_MSG_IFDOWN | NETIF_MSG_RX_ERR |
60 				NETIF_MSG_TX_ERR;
61 
62 static int debug = -1;
63 module_param(debug, int, S_IRUGO);
64 MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");
65 
66 static void do_set_multicast(struct work_struct *w)
67 {
68 	struct net_device_context *ndevctx =
69 		container_of(w, struct net_device_context, work);
70 	struct netvsc_device *nvdev;
71 	struct rndis_device *rdev;
72 
73 	nvdev = hv_get_drvdata(ndevctx->device_ctx);
74 	if (nvdev == NULL || nvdev->ndev == NULL)
75 		return;
76 
77 	rdev = nvdev->extension;
78 	if (rdev == NULL)
79 		return;
80 
81 	if (nvdev->ndev->flags & IFF_PROMISC)
82 		rndis_filter_set_packet_filter(rdev,
83 			NDIS_PACKET_TYPE_PROMISCUOUS);
84 	else
85 		rndis_filter_set_packet_filter(rdev,
86 			NDIS_PACKET_TYPE_BROADCAST |
87 			NDIS_PACKET_TYPE_ALL_MULTICAST |
88 			NDIS_PACKET_TYPE_DIRECTED);
89 }
90 
91 static void netvsc_set_multicast_list(struct net_device *net)
92 {
93 	struct net_device_context *net_device_ctx = netdev_priv(net);
94 
95 	schedule_work(&net_device_ctx->work);
96 }
97 
98 static int netvsc_open(struct net_device *net)
99 {
100 	struct net_device_context *net_device_ctx = netdev_priv(net);
101 	struct hv_device *device_obj = net_device_ctx->device_ctx;
102 	struct netvsc_device *nvdev;
103 	struct rndis_device *rdev;
104 	int ret = 0;
105 
106 	netif_carrier_off(net);
107 
108 	/* Open up the device */
109 	ret = rndis_filter_open(device_obj);
110 	if (ret != 0) {
111 		netdev_err(net, "unable to open device (ret %d).\n", ret);
112 		return ret;
113 	}
114 
115 	netif_tx_wake_all_queues(net);
116 
117 	nvdev = hv_get_drvdata(device_obj);
118 	rdev = nvdev->extension;
119 	if (!rdev->link_state)
120 		netif_carrier_on(net);
121 
122 	return ret;
123 }
124 
125 static int netvsc_close(struct net_device *net)
126 {
127 	struct net_device_context *net_device_ctx = netdev_priv(net);
128 	struct hv_device *device_obj = net_device_ctx->device_ctx;
129 	struct netvsc_device *nvdev = hv_get_drvdata(device_obj);
130 	int ret;
131 	u32 aread, awrite, i, msec = 10, retry = 0, retry_max = 20;
132 	struct vmbus_channel *chn;
133 
134 	netif_tx_disable(net);
135 
136 	/* Make sure netvsc_set_multicast_list doesn't re-enable filter! */
137 	cancel_work_sync(&net_device_ctx->work);
138 	ret = rndis_filter_close(device_obj);
139 	if (ret != 0) {
140 		netdev_err(net, "unable to close device (ret %d).\n", ret);
141 		return ret;
142 	}
143 
144 	/* Ensure pending bytes in ring are read */
145 	while (true) {
146 		aread = 0;
147 		for (i = 0; i < nvdev->num_chn; i++) {
148 			chn = nvdev->chn_table[i];
149 			if (!chn)
150 				continue;
151 
152 			hv_get_ringbuffer_availbytes(&chn->inbound, &aread,
153 						     &awrite);
154 
155 			if (aread)
156 				break;
157 
158 			hv_get_ringbuffer_availbytes(&chn->outbound, &aread,
159 						     &awrite);
160 
161 			if (aread)
162 				break;
163 		}
164 
165 		retry++;
166 		if (retry > retry_max || aread == 0)
167 			break;
168 
169 		msleep(msec);
170 
171 		if (msec < 1000)
172 			msec *= 2;
173 	}
174 
175 	if (aread) {
176 		netdev_err(net, "Ring buffer not empty after closing rndis\n");
177 		ret = -ETIMEDOUT;
178 	}
179 
180 	return ret;
181 }
182 
183 static void *init_ppi_data(struct rndis_message *msg, u32 ppi_size,
184 				int pkt_type)
185 {
186 	struct rndis_packet *rndis_pkt;
187 	struct rndis_per_packet_info *ppi;
188 
189 	rndis_pkt = &msg->msg.pkt;
190 	rndis_pkt->data_offset += ppi_size;
191 
192 	ppi = (struct rndis_per_packet_info *)((void *)rndis_pkt +
193 		rndis_pkt->per_pkt_info_offset + rndis_pkt->per_pkt_info_len);
194 
195 	ppi->size = ppi_size;
196 	ppi->type = pkt_type;
197 	ppi->ppi_offset = sizeof(struct rndis_per_packet_info);
198 
199 	rndis_pkt->per_pkt_info_len += ppi_size;
200 
201 	return ppi;
202 }
203 
204 static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
205 			void *accel_priv, select_queue_fallback_t fallback)
206 {
207 	struct net_device_context *net_device_ctx = netdev_priv(ndev);
208 	struct hv_device *hdev =  net_device_ctx->device_ctx;
209 	struct netvsc_device *nvsc_dev = hv_get_drvdata(hdev);
210 	u32 hash;
211 	u16 q_idx = 0;
212 
213 	if (nvsc_dev == NULL || ndev->real_num_tx_queues <= 1)
214 		return 0;
215 
216 	hash = skb_get_hash(skb);
217 	q_idx = nvsc_dev->send_table[hash % VRSS_SEND_TAB_SIZE] %
218 		ndev->real_num_tx_queues;
219 
220 	if (!nvsc_dev->chn_table[q_idx])
221 		q_idx = 0;
222 
223 	return q_idx;
224 }
225 
226 static u32 fill_pg_buf(struct page *page, u32 offset, u32 len,
227 			struct hv_page_buffer *pb)
228 {
229 	int j = 0;
230 
231 	/* Deal with compund pages by ignoring unused part
232 	 * of the page.
233 	 */
234 	page += (offset >> PAGE_SHIFT);
235 	offset &= ~PAGE_MASK;
236 
237 	while (len > 0) {
238 		unsigned long bytes;
239 
240 		bytes = PAGE_SIZE - offset;
241 		if (bytes > len)
242 			bytes = len;
243 		pb[j].pfn = page_to_pfn(page);
244 		pb[j].offset = offset;
245 		pb[j].len = bytes;
246 
247 		offset += bytes;
248 		len -= bytes;
249 
250 		if (offset == PAGE_SIZE && len) {
251 			page++;
252 			offset = 0;
253 			j++;
254 		}
255 	}
256 
257 	return j + 1;
258 }
259 
260 static u32 init_page_array(void *hdr, u32 len, struct sk_buff *skb,
261 			   struct hv_netvsc_packet *packet,
262 			   struct hv_page_buffer **page_buf)
263 {
264 	struct hv_page_buffer *pb = *page_buf;
265 	u32 slots_used = 0;
266 	char *data = skb->data;
267 	int frags = skb_shinfo(skb)->nr_frags;
268 	int i;
269 
270 	/* The packet is laid out thus:
271 	 * 1. hdr: RNDIS header and PPI
272 	 * 2. skb linear data
273 	 * 3. skb fragment data
274 	 */
275 	if (hdr != NULL)
276 		slots_used += fill_pg_buf(virt_to_page(hdr),
277 					offset_in_page(hdr),
278 					len, &pb[slots_used]);
279 
280 	packet->rmsg_size = len;
281 	packet->rmsg_pgcnt = slots_used;
282 
283 	slots_used += fill_pg_buf(virt_to_page(data),
284 				offset_in_page(data),
285 				skb_headlen(skb), &pb[slots_used]);
286 
287 	for (i = 0; i < frags; i++) {
288 		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
289 
290 		slots_used += fill_pg_buf(skb_frag_page(frag),
291 					frag->page_offset,
292 					skb_frag_size(frag), &pb[slots_used]);
293 	}
294 	return slots_used;
295 }
296 
297 static int count_skb_frag_slots(struct sk_buff *skb)
298 {
299 	int i, frags = skb_shinfo(skb)->nr_frags;
300 	int pages = 0;
301 
302 	for (i = 0; i < frags; i++) {
303 		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
304 		unsigned long size = skb_frag_size(frag);
305 		unsigned long offset = frag->page_offset;
306 
307 		/* Skip unused frames from start of page */
308 		offset &= ~PAGE_MASK;
309 		pages += PFN_UP(offset + size);
310 	}
311 	return pages;
312 }
313 
314 static int netvsc_get_slots(struct sk_buff *skb)
315 {
316 	char *data = skb->data;
317 	unsigned int offset = offset_in_page(data);
318 	unsigned int len = skb_headlen(skb);
319 	int slots;
320 	int frag_slots;
321 
322 	slots = DIV_ROUND_UP(offset + len, PAGE_SIZE);
323 	frag_slots = count_skb_frag_slots(skb);
324 	return slots + frag_slots;
325 }
326 
327 static u32 get_net_transport_info(struct sk_buff *skb, u32 *trans_off)
328 {
329 	u32 ret_val = TRANSPORT_INFO_NOT_IP;
330 
331 	if ((eth_hdr(skb)->h_proto != htons(ETH_P_IP)) &&
332 		(eth_hdr(skb)->h_proto != htons(ETH_P_IPV6))) {
333 		goto not_ip;
334 	}
335 
336 	*trans_off = skb_transport_offset(skb);
337 
338 	if ((eth_hdr(skb)->h_proto == htons(ETH_P_IP))) {
339 		struct iphdr *iphdr = ip_hdr(skb);
340 
341 		if (iphdr->protocol == IPPROTO_TCP)
342 			ret_val = TRANSPORT_INFO_IPV4_TCP;
343 		else if (iphdr->protocol == IPPROTO_UDP)
344 			ret_val = TRANSPORT_INFO_IPV4_UDP;
345 	} else {
346 		if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
347 			ret_val = TRANSPORT_INFO_IPV6_TCP;
348 		else if (ipv6_hdr(skb)->nexthdr == IPPROTO_UDP)
349 			ret_val = TRANSPORT_INFO_IPV6_UDP;
350 	}
351 
352 not_ip:
353 	return ret_val;
354 }
355 
356 static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
357 {
358 	struct net_device_context *net_device_ctx = netdev_priv(net);
359 	struct hv_netvsc_packet *packet = NULL;
360 	int ret;
361 	unsigned int num_data_pgs;
362 	struct rndis_message *rndis_msg;
363 	struct rndis_packet *rndis_pkt;
364 	u32 rndis_msg_size;
365 	bool isvlan;
366 	bool linear = false;
367 	struct rndis_per_packet_info *ppi;
368 	struct ndis_tcp_ip_checksum_info *csum_info;
369 	struct ndis_tcp_lso_info *lso_info;
370 	int  hdr_offset;
371 	u32 net_trans_info;
372 	u32 hash;
373 	u32 skb_length;
374 	struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT];
375 	struct hv_page_buffer *pb = page_buf;
376 	struct netvsc_stats *tx_stats = this_cpu_ptr(net_device_ctx->tx_stats);
377 
378 	/* We will atmost need two pages to describe the rndis
379 	 * header. We can only transmit MAX_PAGE_BUFFER_COUNT number
380 	 * of pages in a single packet. If skb is scattered around
381 	 * more pages we try linearizing it.
382 	 */
383 
384 check_size:
385 	skb_length = skb->len;
386 	num_data_pgs = netvsc_get_slots(skb) + 2;
387 	if (num_data_pgs > MAX_PAGE_BUFFER_COUNT && linear) {
388 		net_alert_ratelimited("packet too big: %u pages (%u bytes)\n",
389 				      num_data_pgs, skb->len);
390 		ret = -EFAULT;
391 		goto drop;
392 	} else if (num_data_pgs > MAX_PAGE_BUFFER_COUNT) {
393 		if (skb_linearize(skb)) {
394 			net_alert_ratelimited("failed to linearize skb\n");
395 			ret = -ENOMEM;
396 			goto drop;
397 		}
398 		linear = true;
399 		goto check_size;
400 	}
401 
402 	/*
403 	 * Place the rndis header in the skb head room and
404 	 * the skb->cb will be used for hv_netvsc_packet
405 	 * structure.
406 	 */
407 	ret = skb_cow_head(skb, RNDIS_AND_PPI_SIZE);
408 	if (ret) {
409 		netdev_err(net, "unable to alloc hv_netvsc_packet\n");
410 		ret = -ENOMEM;
411 		goto drop;
412 	}
413 	/* Use the skb control buffer for building up the packet */
414 	BUILD_BUG_ON(sizeof(struct hv_netvsc_packet) >
415 			FIELD_SIZEOF(struct sk_buff, cb));
416 	packet = (struct hv_netvsc_packet *)skb->cb;
417 
418 
419 	packet->q_idx = skb_get_queue_mapping(skb);
420 
421 	packet->total_data_buflen = skb->len;
422 
423 	rndis_msg = (struct rndis_message *)skb->head;
424 
425 	memset(rndis_msg, 0, RNDIS_AND_PPI_SIZE);
426 
427 	isvlan = skb->vlan_tci & VLAN_TAG_PRESENT;
428 
429 	/* Add the rndis header */
430 	rndis_msg->ndis_msg_type = RNDIS_MSG_PACKET;
431 	rndis_msg->msg_len = packet->total_data_buflen;
432 	rndis_pkt = &rndis_msg->msg.pkt;
433 	rndis_pkt->data_offset = sizeof(struct rndis_packet);
434 	rndis_pkt->data_len = packet->total_data_buflen;
435 	rndis_pkt->per_pkt_info_offset = sizeof(struct rndis_packet);
436 
437 	rndis_msg_size = RNDIS_MESSAGE_SIZE(struct rndis_packet);
438 
439 	hash = skb_get_hash_raw(skb);
440 	if (hash != 0 && net->real_num_tx_queues > 1) {
441 		rndis_msg_size += NDIS_HASH_PPI_SIZE;
442 		ppi = init_ppi_data(rndis_msg, NDIS_HASH_PPI_SIZE,
443 				    NBL_HASH_VALUE);
444 		*(u32 *)((void *)ppi + ppi->ppi_offset) = hash;
445 	}
446 
447 	if (isvlan) {
448 		struct ndis_pkt_8021q_info *vlan;
449 
450 		rndis_msg_size += NDIS_VLAN_PPI_SIZE;
451 		ppi = init_ppi_data(rndis_msg, NDIS_VLAN_PPI_SIZE,
452 					IEEE_8021Q_INFO);
453 		vlan = (struct ndis_pkt_8021q_info *)((void *)ppi +
454 						ppi->ppi_offset);
455 		vlan->vlanid = skb->vlan_tci & VLAN_VID_MASK;
456 		vlan->pri = (skb->vlan_tci & VLAN_PRIO_MASK) >>
457 				VLAN_PRIO_SHIFT;
458 	}
459 
460 	net_trans_info = get_net_transport_info(skb, &hdr_offset);
461 	if (net_trans_info == TRANSPORT_INFO_NOT_IP)
462 		goto do_send;
463 
464 	/*
465 	 * Setup the sendside checksum offload only if this is not a
466 	 * GSO packet.
467 	 */
468 	if (skb_is_gso(skb))
469 		goto do_lso;
470 
471 	if ((skb->ip_summed == CHECKSUM_NONE) ||
472 	    (skb->ip_summed == CHECKSUM_UNNECESSARY))
473 		goto do_send;
474 
475 	rndis_msg_size += NDIS_CSUM_PPI_SIZE;
476 	ppi = init_ppi_data(rndis_msg, NDIS_CSUM_PPI_SIZE,
477 			    TCPIP_CHKSUM_PKTINFO);
478 
479 	csum_info = (struct ndis_tcp_ip_checksum_info *)((void *)ppi +
480 			ppi->ppi_offset);
481 
482 	if (net_trans_info & (INFO_IPV4 << 16))
483 		csum_info->transmit.is_ipv4 = 1;
484 	else
485 		csum_info->transmit.is_ipv6 = 1;
486 
487 	if (net_trans_info & INFO_TCP) {
488 		csum_info->transmit.tcp_checksum = 1;
489 		csum_info->transmit.tcp_header_offset = hdr_offset;
490 	} else if (net_trans_info & INFO_UDP) {
491 		/* UDP checksum offload is not supported on ws2008r2.
492 		 * Furthermore, on ws2012 and ws2012r2, there are some
493 		 * issues with udp checksum offload from Linux guests.
494 		 * (these are host issues).
495 		 * For now compute the checksum here.
496 		 */
497 		struct udphdr *uh;
498 		u16 udp_len;
499 
500 		ret = skb_cow_head(skb, 0);
501 		if (ret)
502 			goto drop;
503 
504 		uh = udp_hdr(skb);
505 		udp_len = ntohs(uh->len);
506 		uh->check = 0;
507 		uh->check = csum_tcpudp_magic(ip_hdr(skb)->saddr,
508 					      ip_hdr(skb)->daddr,
509 					      udp_len, IPPROTO_UDP,
510 					      csum_partial(uh, udp_len, 0));
511 		if (uh->check == 0)
512 			uh->check = CSUM_MANGLED_0;
513 
514 		csum_info->transmit.udp_checksum = 0;
515 	}
516 	goto do_send;
517 
518 do_lso:
519 	rndis_msg_size += NDIS_LSO_PPI_SIZE;
520 	ppi = init_ppi_data(rndis_msg, NDIS_LSO_PPI_SIZE,
521 			    TCP_LARGESEND_PKTINFO);
522 
523 	lso_info = (struct ndis_tcp_lso_info *)((void *)ppi +
524 			ppi->ppi_offset);
525 
526 	lso_info->lso_v2_transmit.type = NDIS_TCP_LARGE_SEND_OFFLOAD_V2_TYPE;
527 	if (net_trans_info & (INFO_IPV4 << 16)) {
528 		lso_info->lso_v2_transmit.ip_version =
529 			NDIS_TCP_LARGE_SEND_OFFLOAD_IPV4;
530 		ip_hdr(skb)->tot_len = 0;
531 		ip_hdr(skb)->check = 0;
532 		tcp_hdr(skb)->check =
533 		~csum_tcpudp_magic(ip_hdr(skb)->saddr,
534 				   ip_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
535 	} else {
536 		lso_info->lso_v2_transmit.ip_version =
537 			NDIS_TCP_LARGE_SEND_OFFLOAD_IPV6;
538 		ipv6_hdr(skb)->payload_len = 0;
539 		tcp_hdr(skb)->check =
540 		~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
541 				&ipv6_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
542 	}
543 	lso_info->lso_v2_transmit.tcp_header_offset = hdr_offset;
544 	lso_info->lso_v2_transmit.mss = skb_shinfo(skb)->gso_size;
545 
546 do_send:
547 	/* Start filling in the page buffers with the rndis hdr */
548 	rndis_msg->msg_len += rndis_msg_size;
549 	packet->total_data_buflen = rndis_msg->msg_len;
550 	packet->page_buf_cnt = init_page_array(rndis_msg, rndis_msg_size,
551 					       skb, packet, &pb);
552 
553 	/* timestamp packet in software */
554 	skb_tx_timestamp(skb);
555 	ret = netvsc_send(net_device_ctx->device_ctx, packet,
556 			  rndis_msg, &pb, skb);
557 
558 drop:
559 	if (ret == 0) {
560 		u64_stats_update_begin(&tx_stats->syncp);
561 		tx_stats->packets++;
562 		tx_stats->bytes += skb_length;
563 		u64_stats_update_end(&tx_stats->syncp);
564 	} else {
565 		if (ret != -EAGAIN) {
566 			dev_kfree_skb_any(skb);
567 			net->stats.tx_dropped++;
568 		}
569 	}
570 
571 	return (ret == -EAGAIN) ? NETDEV_TX_BUSY : NETDEV_TX_OK;
572 }
573 
574 /*
575  * netvsc_linkstatus_callback - Link up/down notification
576  */
577 void netvsc_linkstatus_callback(struct hv_device *device_obj,
578 				struct rndis_message *resp)
579 {
580 	struct rndis_indicate_status *indicate = &resp->msg.indicate_status;
581 	struct net_device *net;
582 	struct net_device_context *ndev_ctx;
583 	struct netvsc_device *net_device;
584 	struct netvsc_reconfig *event;
585 	unsigned long flags;
586 
587 	/* Handle link change statuses only */
588 	if (indicate->status != RNDIS_STATUS_NETWORK_CHANGE &&
589 	    indicate->status != RNDIS_STATUS_MEDIA_CONNECT &&
590 	    indicate->status != RNDIS_STATUS_MEDIA_DISCONNECT)
591 		return;
592 
593 	net_device = hv_get_drvdata(device_obj);
594 	net = net_device->ndev;
595 
596 	if (!net || net->reg_state != NETREG_REGISTERED)
597 		return;
598 
599 	ndev_ctx = netdev_priv(net);
600 
601 	event = kzalloc(sizeof(*event), GFP_ATOMIC);
602 	if (!event)
603 		return;
604 	event->event = indicate->status;
605 
606 	spin_lock_irqsave(&ndev_ctx->lock, flags);
607 	list_add_tail(&event->list, &ndev_ctx->reconfig_events);
608 	spin_unlock_irqrestore(&ndev_ctx->lock, flags);
609 
610 	schedule_delayed_work(&ndev_ctx->dwork, 0);
611 }
612 
613 /*
614  * netvsc_recv_callback -  Callback when we receive a packet from the
615  * "wire" on the specified device.
616  */
617 int netvsc_recv_callback(struct hv_device *device_obj,
618 				struct hv_netvsc_packet *packet,
619 				void **data,
620 				struct ndis_tcp_ip_checksum_info *csum_info,
621 				struct vmbus_channel *channel,
622 				u16 vlan_tci)
623 {
624 	struct net_device *net;
625 	struct net_device_context *net_device_ctx;
626 	struct sk_buff *skb;
627 	struct netvsc_stats *rx_stats;
628 
629 	net = ((struct netvsc_device *)hv_get_drvdata(device_obj))->ndev;
630 	if (!net || net->reg_state != NETREG_REGISTERED) {
631 		return NVSP_STAT_FAIL;
632 	}
633 	net_device_ctx = netdev_priv(net);
634 	rx_stats = this_cpu_ptr(net_device_ctx->rx_stats);
635 
636 	/* Allocate a skb - TODO direct I/O to pages? */
637 	skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
638 	if (unlikely(!skb)) {
639 		++net->stats.rx_dropped;
640 		return NVSP_STAT_FAIL;
641 	}
642 
643 	/*
644 	 * Copy to skb. This copy is needed here since the memory pointed by
645 	 * hv_netvsc_packet cannot be deallocated
646 	 */
647 	memcpy(skb_put(skb, packet->total_data_buflen), *data,
648 		packet->total_data_buflen);
649 
650 	skb->protocol = eth_type_trans(skb, net);
651 	if (csum_info) {
652 		/* We only look at the IP checksum here.
653 		 * Should we be dropping the packet if checksum
654 		 * failed? How do we deal with other checksums - TCP/UDP?
655 		 */
656 		if (csum_info->receive.ip_checksum_succeeded)
657 			skb->ip_summed = CHECKSUM_UNNECESSARY;
658 		else
659 			skb->ip_summed = CHECKSUM_NONE;
660 	}
661 
662 	if (vlan_tci & VLAN_TAG_PRESENT)
663 		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
664 				       vlan_tci);
665 
666 	skb_record_rx_queue(skb, channel->
667 			    offermsg.offer.sub_channel_index);
668 
669 	u64_stats_update_begin(&rx_stats->syncp);
670 	rx_stats->packets++;
671 	rx_stats->bytes += packet->total_data_buflen;
672 	u64_stats_update_end(&rx_stats->syncp);
673 
674 	/*
675 	 * Pass the skb back up. Network stack will deallocate the skb when it
676 	 * is done.
677 	 * TODO - use NAPI?
678 	 */
679 	netif_rx(skb);
680 
681 	return 0;
682 }
683 
684 static void netvsc_get_drvinfo(struct net_device *net,
685 			       struct ethtool_drvinfo *info)
686 {
687 	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
688 	strlcpy(info->fw_version, "N/A", sizeof(info->fw_version));
689 }
690 
691 static void netvsc_get_channels(struct net_device *net,
692 				struct ethtool_channels *channel)
693 {
694 	struct net_device_context *net_device_ctx = netdev_priv(net);
695 	struct hv_device *dev = net_device_ctx->device_ctx;
696 	struct netvsc_device *nvdev = hv_get_drvdata(dev);
697 
698 	if (nvdev) {
699 		channel->max_combined	= nvdev->max_chn;
700 		channel->combined_count = nvdev->num_chn;
701 	}
702 }
703 
704 static int netvsc_set_channels(struct net_device *net,
705 			       struct ethtool_channels *channels)
706 {
707 	struct net_device_context *net_device_ctx = netdev_priv(net);
708 	struct hv_device *dev = net_device_ctx->device_ctx;
709 	struct netvsc_device *nvdev = hv_get_drvdata(dev);
710 	struct netvsc_device_info device_info;
711 	u32 num_chn;
712 	u32 max_chn;
713 	int ret = 0;
714 	bool recovering = false;
715 
716 	if (!nvdev || nvdev->destroy)
717 		return -ENODEV;
718 
719 	num_chn = nvdev->num_chn;
720 	max_chn = min_t(u32, nvdev->max_chn, num_online_cpus());
721 
722 	if (nvdev->nvsp_version < NVSP_PROTOCOL_VERSION_5) {
723 		pr_info("vRSS unsupported before NVSP Version 5\n");
724 		return -EINVAL;
725 	}
726 
727 	/* We do not support rx, tx, or other */
728 	if (!channels ||
729 	    channels->rx_count ||
730 	    channels->tx_count ||
731 	    channels->other_count ||
732 	    (channels->combined_count < 1))
733 		return -EINVAL;
734 
735 	if (channels->combined_count > max_chn) {
736 		pr_info("combined channels too high, using %d\n", max_chn);
737 		channels->combined_count = max_chn;
738 	}
739 
740 	ret = netvsc_close(net);
741 	if (ret)
742 		goto out;
743 
744  do_set:
745 	nvdev->start_remove = true;
746 	rndis_filter_device_remove(dev);
747 
748 	nvdev->num_chn = channels->combined_count;
749 
750 	net_device_ctx->device_ctx = dev;
751 	hv_set_drvdata(dev, net);
752 
753 	memset(&device_info, 0, sizeof(device_info));
754 	device_info.num_chn = nvdev->num_chn; /* passed to RNDIS */
755 	device_info.ring_size = ring_size;
756 	device_info.max_num_vrss_chns = max_num_vrss_chns;
757 
758 	ret = rndis_filter_device_add(dev, &device_info);
759 	if (ret) {
760 		if (recovering) {
761 			netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
762 			return ret;
763 		}
764 		goto recover;
765 	}
766 
767 	nvdev = hv_get_drvdata(dev);
768 
769 	ret = netif_set_real_num_tx_queues(net, nvdev->num_chn);
770 	if (ret) {
771 		if (recovering) {
772 			netdev_err(net, "could not set tx queue count (ret %d)\n", ret);
773 			return ret;
774 		}
775 		goto recover;
776 	}
777 
778 	ret = netif_set_real_num_rx_queues(net, nvdev->num_chn);
779 	if (ret) {
780 		if (recovering) {
781 			netdev_err(net, "could not set rx queue count (ret %d)\n", ret);
782 			return ret;
783 		}
784 		goto recover;
785 	}
786 
787  out:
788 	netvsc_open(net);
789 
790 	return ret;
791 
792  recover:
793 	/* If the above failed, we attempt to recover through the same
794 	 * process but with the original number of channels.
795 	 */
796 	netdev_err(net, "could not set channels, recovering\n");
797 	recovering = true;
798 	channels->combined_count = num_chn;
799 	goto do_set;
800 }
801 
802 static int netvsc_change_mtu(struct net_device *ndev, int mtu)
803 {
804 	struct net_device_context *ndevctx = netdev_priv(ndev);
805 	struct hv_device *hdev =  ndevctx->device_ctx;
806 	struct netvsc_device *nvdev = hv_get_drvdata(hdev);
807 	struct netvsc_device_info device_info;
808 	int limit = ETH_DATA_LEN;
809 	int ret = 0;
810 
811 	if (nvdev == NULL || nvdev->destroy)
812 		return -ENODEV;
813 
814 	if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2)
815 		limit = NETVSC_MTU - ETH_HLEN;
816 
817 	if (mtu < NETVSC_MTU_MIN || mtu > limit)
818 		return -EINVAL;
819 
820 	ret = netvsc_close(ndev);
821 	if (ret)
822 		goto out;
823 
824 	nvdev->start_remove = true;
825 	rndis_filter_device_remove(hdev);
826 
827 	ndev->mtu = mtu;
828 
829 	ndevctx->device_ctx = hdev;
830 	hv_set_drvdata(hdev, ndev);
831 
832 	memset(&device_info, 0, sizeof(device_info));
833 	device_info.ring_size = ring_size;
834 	device_info.num_chn = nvdev->num_chn;
835 	device_info.max_num_vrss_chns = max_num_vrss_chns;
836 	rndis_filter_device_add(hdev, &device_info);
837 
838 out:
839 	netvsc_open(ndev);
840 
841 	return ret;
842 }
843 
844 static struct rtnl_link_stats64 *netvsc_get_stats64(struct net_device *net,
845 						    struct rtnl_link_stats64 *t)
846 {
847 	struct net_device_context *ndev_ctx = netdev_priv(net);
848 	int cpu;
849 
850 	for_each_possible_cpu(cpu) {
851 		struct netvsc_stats *tx_stats = per_cpu_ptr(ndev_ctx->tx_stats,
852 							    cpu);
853 		struct netvsc_stats *rx_stats = per_cpu_ptr(ndev_ctx->rx_stats,
854 							    cpu);
855 		u64 tx_packets, tx_bytes, rx_packets, rx_bytes;
856 		unsigned int start;
857 
858 		do {
859 			start = u64_stats_fetch_begin_irq(&tx_stats->syncp);
860 			tx_packets = tx_stats->packets;
861 			tx_bytes = tx_stats->bytes;
862 		} while (u64_stats_fetch_retry_irq(&tx_stats->syncp, start));
863 
864 		do {
865 			start = u64_stats_fetch_begin_irq(&rx_stats->syncp);
866 			rx_packets = rx_stats->packets;
867 			rx_bytes = rx_stats->bytes;
868 		} while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start));
869 
870 		t->tx_bytes	+= tx_bytes;
871 		t->tx_packets	+= tx_packets;
872 		t->rx_bytes	+= rx_bytes;
873 		t->rx_packets	+= rx_packets;
874 	}
875 
876 	t->tx_dropped	= net->stats.tx_dropped;
877 	t->tx_errors	= net->stats.tx_dropped;
878 
879 	t->rx_dropped	= net->stats.rx_dropped;
880 	t->rx_errors	= net->stats.rx_errors;
881 
882 	return t;
883 }
884 
885 static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
886 {
887 	struct net_device_context *ndevctx = netdev_priv(ndev);
888 	struct hv_device *hdev =  ndevctx->device_ctx;
889 	struct sockaddr *addr = p;
890 	char save_adr[ETH_ALEN];
891 	unsigned char save_aatype;
892 	int err;
893 
894 	memcpy(save_adr, ndev->dev_addr, ETH_ALEN);
895 	save_aatype = ndev->addr_assign_type;
896 
897 	err = eth_mac_addr(ndev, p);
898 	if (err != 0)
899 		return err;
900 
901 	err = rndis_filter_set_device_mac(hdev, addr->sa_data);
902 	if (err != 0) {
903 		/* roll back to saved MAC */
904 		memcpy(ndev->dev_addr, save_adr, ETH_ALEN);
905 		ndev->addr_assign_type = save_aatype;
906 	}
907 
908 	return err;
909 }
910 
911 #ifdef CONFIG_NET_POLL_CONTROLLER
912 static void netvsc_poll_controller(struct net_device *net)
913 {
914 	/* As netvsc_start_xmit() works synchronous we don't have to
915 	 * trigger anything here.
916 	 */
917 }
918 #endif
919 
920 static const struct ethtool_ops ethtool_ops = {
921 	.get_drvinfo	= netvsc_get_drvinfo,
922 	.get_link	= ethtool_op_get_link,
923 	.get_channels   = netvsc_get_channels,
924 	.set_channels   = netvsc_set_channels,
925 	.get_ts_info	= ethtool_op_get_ts_info,
926 };
927 
928 static const struct net_device_ops device_ops = {
929 	.ndo_open =			netvsc_open,
930 	.ndo_stop =			netvsc_close,
931 	.ndo_start_xmit =		netvsc_start_xmit,
932 	.ndo_set_rx_mode =		netvsc_set_multicast_list,
933 	.ndo_change_mtu =		netvsc_change_mtu,
934 	.ndo_validate_addr =		eth_validate_addr,
935 	.ndo_set_mac_address =		netvsc_set_mac_addr,
936 	.ndo_select_queue =		netvsc_select_queue,
937 	.ndo_get_stats64 =		netvsc_get_stats64,
938 #ifdef CONFIG_NET_POLL_CONTROLLER
939 	.ndo_poll_controller =		netvsc_poll_controller,
940 #endif
941 };
942 
943 /*
944  * Handle link status changes. For RNDIS_STATUS_NETWORK_CHANGE emulate link
945  * down/up sequence. In case of RNDIS_STATUS_MEDIA_CONNECT when carrier is
946  * present send GARP packet to network peers with netif_notify_peers().
947  */
948 static void netvsc_link_change(struct work_struct *w)
949 {
950 	struct net_device_context *ndev_ctx;
951 	struct net_device *net;
952 	struct netvsc_device *net_device;
953 	struct rndis_device *rdev;
954 	struct netvsc_reconfig *event = NULL;
955 	bool notify = false, reschedule = false;
956 	unsigned long flags, next_reconfig, delay;
957 
958 	ndev_ctx = container_of(w, struct net_device_context, dwork.work);
959 	net_device = hv_get_drvdata(ndev_ctx->device_ctx);
960 	rdev = net_device->extension;
961 	net = net_device->ndev;
962 
963 	next_reconfig = ndev_ctx->last_reconfig + LINKCHANGE_INT;
964 	if (time_is_after_jiffies(next_reconfig)) {
965 		/* link_watch only sends one notification with current state
966 		 * per second, avoid doing reconfig more frequently. Handle
967 		 * wrap around.
968 		 */
969 		delay = next_reconfig - jiffies;
970 		delay = delay < LINKCHANGE_INT ? delay : LINKCHANGE_INT;
971 		schedule_delayed_work(&ndev_ctx->dwork, delay);
972 		return;
973 	}
974 	ndev_ctx->last_reconfig = jiffies;
975 
976 	spin_lock_irqsave(&ndev_ctx->lock, flags);
977 	if (!list_empty(&ndev_ctx->reconfig_events)) {
978 		event = list_first_entry(&ndev_ctx->reconfig_events,
979 					 struct netvsc_reconfig, list);
980 		list_del(&event->list);
981 		reschedule = !list_empty(&ndev_ctx->reconfig_events);
982 	}
983 	spin_unlock_irqrestore(&ndev_ctx->lock, flags);
984 
985 	if (!event)
986 		return;
987 
988 	rtnl_lock();
989 
990 	switch (event->event) {
991 		/* Only the following events are possible due to the check in
992 		 * netvsc_linkstatus_callback()
993 		 */
994 	case RNDIS_STATUS_MEDIA_CONNECT:
995 		if (rdev->link_state) {
996 			rdev->link_state = false;
997 			netif_carrier_on(net);
998 			netif_tx_wake_all_queues(net);
999 		} else {
1000 			notify = true;
1001 		}
1002 		kfree(event);
1003 		break;
1004 	case RNDIS_STATUS_MEDIA_DISCONNECT:
1005 		if (!rdev->link_state) {
1006 			rdev->link_state = true;
1007 			netif_carrier_off(net);
1008 			netif_tx_stop_all_queues(net);
1009 		}
1010 		kfree(event);
1011 		break;
1012 	case RNDIS_STATUS_NETWORK_CHANGE:
1013 		/* Only makes sense if carrier is present */
1014 		if (!rdev->link_state) {
1015 			rdev->link_state = true;
1016 			netif_carrier_off(net);
1017 			netif_tx_stop_all_queues(net);
1018 			event->event = RNDIS_STATUS_MEDIA_CONNECT;
1019 			spin_lock_irqsave(&ndev_ctx->lock, flags);
1020 			list_add_tail(&event->list, &ndev_ctx->reconfig_events);
1021 			spin_unlock_irqrestore(&ndev_ctx->lock, flags);
1022 			reschedule = true;
1023 		}
1024 		break;
1025 	}
1026 
1027 	rtnl_unlock();
1028 
1029 	if (notify)
1030 		netdev_notify_peers(net);
1031 
1032 	/* link_watch only sends one notification with current state per
1033 	 * second, handle next reconfig event in 2 seconds.
1034 	 */
1035 	if (reschedule)
1036 		schedule_delayed_work(&ndev_ctx->dwork, LINKCHANGE_INT);
1037 }
1038 
1039 static void netvsc_free_netdev(struct net_device *netdev)
1040 {
1041 	struct net_device_context *net_device_ctx = netdev_priv(netdev);
1042 
1043 	free_percpu(net_device_ctx->tx_stats);
1044 	free_percpu(net_device_ctx->rx_stats);
1045 	free_netdev(netdev);
1046 }
1047 
1048 static int netvsc_probe(struct hv_device *dev,
1049 			const struct hv_vmbus_device_id *dev_id)
1050 {
1051 	struct net_device *net = NULL;
1052 	struct net_device_context *net_device_ctx;
1053 	struct netvsc_device_info device_info;
1054 	struct netvsc_device *nvdev;
1055 	int ret;
1056 
1057 	net = alloc_etherdev_mq(sizeof(struct net_device_context),
1058 				num_online_cpus());
1059 	if (!net)
1060 		return -ENOMEM;
1061 
1062 	netif_carrier_off(net);
1063 
1064 	net_device_ctx = netdev_priv(net);
1065 	net_device_ctx->device_ctx = dev;
1066 	net_device_ctx->msg_enable = netif_msg_init(debug, default_msg);
1067 	if (netif_msg_probe(net_device_ctx))
1068 		netdev_dbg(net, "netvsc msg_enable: %d\n",
1069 			   net_device_ctx->msg_enable);
1070 
1071 	net_device_ctx->tx_stats = netdev_alloc_pcpu_stats(struct netvsc_stats);
1072 	if (!net_device_ctx->tx_stats) {
1073 		free_netdev(net);
1074 		return -ENOMEM;
1075 	}
1076 	net_device_ctx->rx_stats = netdev_alloc_pcpu_stats(struct netvsc_stats);
1077 	if (!net_device_ctx->rx_stats) {
1078 		free_percpu(net_device_ctx->tx_stats);
1079 		free_netdev(net);
1080 		return -ENOMEM;
1081 	}
1082 
1083 	hv_set_drvdata(dev, net);
1084 	INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);
1085 	INIT_WORK(&net_device_ctx->work, do_set_multicast);
1086 
1087 	spin_lock_init(&net_device_ctx->lock);
1088 	INIT_LIST_HEAD(&net_device_ctx->reconfig_events);
1089 
1090 	net->netdev_ops = &device_ops;
1091 
1092 	net->hw_features = NETVSC_HW_FEATURES;
1093 	net->features = NETVSC_HW_FEATURES | NETIF_F_HW_VLAN_CTAG_TX;
1094 
1095 	net->ethtool_ops = &ethtool_ops;
1096 	SET_NETDEV_DEV(net, &dev->device);
1097 
1098 	/* We always need headroom for rndis header */
1099 	net->needed_headroom = RNDIS_AND_PPI_SIZE;
1100 
1101 	/* Notify the netvsc driver of the new device */
1102 	memset(&device_info, 0, sizeof(device_info));
1103 	device_info.ring_size = ring_size;
1104 	device_info.max_num_vrss_chns = max_num_vrss_chns;
1105 	ret = rndis_filter_device_add(dev, &device_info);
1106 	if (ret != 0) {
1107 		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
1108 		netvsc_free_netdev(net);
1109 		hv_set_drvdata(dev, NULL);
1110 		return ret;
1111 	}
1112 	memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);
1113 
1114 	nvdev = hv_get_drvdata(dev);
1115 	netif_set_real_num_tx_queues(net, nvdev->num_chn);
1116 	netif_set_real_num_rx_queues(net, nvdev->num_chn);
1117 
1118 	ret = register_netdev(net);
1119 	if (ret != 0) {
1120 		pr_err("Unable to register netdev.\n");
1121 		rndis_filter_device_remove(dev);
1122 		netvsc_free_netdev(net);
1123 	}
1124 
1125 	return ret;
1126 }
1127 
1128 static int netvsc_remove(struct hv_device *dev)
1129 {
1130 	struct net_device *net;
1131 	struct net_device_context *ndev_ctx;
1132 	struct netvsc_device *net_device;
1133 
1134 	net_device = hv_get_drvdata(dev);
1135 	net = net_device->ndev;
1136 
1137 	if (net == NULL) {
1138 		dev_err(&dev->device, "No net device to remove\n");
1139 		return 0;
1140 	}
1141 
1142 	net_device->start_remove = true;
1143 
1144 	ndev_ctx = netdev_priv(net);
1145 	cancel_delayed_work_sync(&ndev_ctx->dwork);
1146 	cancel_work_sync(&ndev_ctx->work);
1147 
1148 	/* Stop outbound asap */
1149 	netif_tx_disable(net);
1150 
1151 	unregister_netdev(net);
1152 
1153 	/*
1154 	 * Call to the vsc driver to let it know that the device is being
1155 	 * removed
1156 	 */
1157 	rndis_filter_device_remove(dev);
1158 
1159 	netvsc_free_netdev(net);
1160 	return 0;
1161 }
1162 
1163 static const struct hv_vmbus_device_id id_table[] = {
1164 	/* Network guid */
1165 	{ HV_NIC_GUID, },
1166 	{ },
1167 };
1168 
1169 MODULE_DEVICE_TABLE(vmbus, id_table);
1170 
1171 /* The one and only one */
1172 static struct  hv_driver netvsc_drv = {
1173 	.name = KBUILD_MODNAME,
1174 	.id_table = id_table,
1175 	.probe = netvsc_probe,
1176 	.remove = netvsc_remove,
1177 };
1178 
1179 static void __exit netvsc_drv_exit(void)
1180 {
1181 	vmbus_driver_unregister(&netvsc_drv);
1182 }
1183 
1184 static int __init netvsc_drv_init(void)
1185 {
1186 	if (ring_size < RING_SIZE_MIN) {
1187 		ring_size = RING_SIZE_MIN;
1188 		pr_info("Increased ring_size to %d (min allowed)\n",
1189 			ring_size);
1190 	}
1191 	return vmbus_driver_register(&netvsc_drv);
1192 }
1193 
1194 MODULE_LICENSE("GPL");
1195 MODULE_DESCRIPTION("Microsoft Hyper-V network driver");
1196 
1197 module_init(netvsc_drv_init);
1198 module_exit(netvsc_drv_exit);
1199