1 /*
2  * Network-device interface management.
3  *
4  * Copyright (c) 2004-2005, Keir Fraser
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License version 2
8  * as published by the Free Software Foundation; or, when distributed
9  * separately from the Linux kernel or incorporated into other
10  * software packages, subject to the following license:
11  *
12  * Permission is hereby granted, free of charge, to any person obtaining a copy
13  * of this source file (the "Software"), to deal in the Software without
14  * restriction, including without limitation the rights to use, copy, modify,
15  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
16  * and to permit persons to whom the Software is furnished to do so, subject to
17  * the following conditions:
18  *
19  * The above copyright notice and this permission notice shall be included in
20  * all copies or substantial portions of the Software.
21  *
22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
28  * IN THE SOFTWARE.
29  */
30 
31 #include "common.h"
32 
33 #include <linux/kthread.h>
34 #include <linux/ethtool.h>
35 #include <linux/rtnetlink.h>
36 #include <linux/if_vlan.h>
37 #include <linux/vmalloc.h>
38 
39 #include <xen/events.h>
40 #include <asm/xen/hypercall.h>
41 #include <xen/balloon.h>
42 
43 #define XENVIF_QUEUE_LENGTH 32
44 #define XENVIF_NAPI_WEIGHT  64
45 
46 /* Number of bytes allowed on the internal guest Rx queue. */
47 #define XENVIF_RX_QUEUE_BYTES (XEN_NETIF_RX_RING_SIZE/2 * PAGE_SIZE)
48 
49 /* This function is used to set SKBTX_DEV_ZEROCOPY as well as
50  * increasing the inflight counter. We need to increase the inflight
51  * counter because core driver calls into xenvif_zerocopy_callback
52  * which calls xenvif_skb_zerocopy_complete.
53  */
54 void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue,
55 				 struct sk_buff *skb)
56 {
57 	skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
58 	atomic_inc(&queue->inflight_packets);
59 }
60 
61 void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue)
62 {
63 	atomic_dec(&queue->inflight_packets);
64 
65 	/* Wake the dealloc thread _after_ decrementing inflight_packets so
66 	 * that if kthread_stop() has already been called, the dealloc thread
67 	 * does not wait forever with nothing to wake it.
68 	 */
69 	wake_up(&queue->dealloc_wq);
70 }
71 
72 int xenvif_schedulable(struct xenvif *vif)
73 {
74 	return netif_running(vif->dev) &&
75 		test_bit(VIF_STATUS_CONNECTED, &vif->status) &&
76 		!vif->disabled;
77 }
78 
79 static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
80 {
81 	struct xenvif_queue *queue = dev_id;
82 
83 	if (RING_HAS_UNCONSUMED_REQUESTS(&queue->tx))
84 		napi_schedule(&queue->napi);
85 
86 	return IRQ_HANDLED;
87 }
88 
89 static int xenvif_poll(struct napi_struct *napi, int budget)
90 {
91 	struct xenvif_queue *queue =
92 		container_of(napi, struct xenvif_queue, napi);
93 	int work_done;
94 
95 	/* This vif is rogue, we pretend we've there is nothing to do
96 	 * for this vif to deschedule it from NAPI. But this interface
97 	 * will be turned off in thread context later.
98 	 */
99 	if (unlikely(queue->vif->disabled)) {
100 		napi_complete(napi);
101 		return 0;
102 	}
103 
104 	work_done = xenvif_tx_action(queue, budget);
105 
106 	if (work_done < budget) {
107 		napi_complete(napi);
108 		xenvif_napi_schedule_or_enable_events(queue);
109 	}
110 
111 	return work_done;
112 }
113 
114 static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
115 {
116 	struct xenvif_queue *queue = dev_id;
117 
118 	xenvif_kick_thread(queue);
119 
120 	return IRQ_HANDLED;
121 }
122 
123 irqreturn_t xenvif_interrupt(int irq, void *dev_id)
124 {
125 	xenvif_tx_interrupt(irq, dev_id);
126 	xenvif_rx_interrupt(irq, dev_id);
127 
128 	return IRQ_HANDLED;
129 }
130 
131 int xenvif_queue_stopped(struct xenvif_queue *queue)
132 {
133 	struct net_device *dev = queue->vif->dev;
134 	unsigned int id = queue->id;
135 	return netif_tx_queue_stopped(netdev_get_tx_queue(dev, id));
136 }
137 
138 void xenvif_wake_queue(struct xenvif_queue *queue)
139 {
140 	struct net_device *dev = queue->vif->dev;
141 	unsigned int id = queue->id;
142 	netif_tx_wake_queue(netdev_get_tx_queue(dev, id));
143 }
144 
145 static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
146 			       void *accel_priv,
147 			       select_queue_fallback_t fallback)
148 {
149 	struct xenvif *vif = netdev_priv(dev);
150 	unsigned int size = vif->hash.size;
151 
152 	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
153 		return fallback(dev, skb) % dev->real_num_tx_queues;
154 
155 	xenvif_set_skb_hash(vif, skb);
156 
157 	if (size == 0)
158 		return skb_get_hash_raw(skb) % dev->real_num_tx_queues;
159 
160 	return vif->hash.mapping[skb_get_hash_raw(skb) % size];
161 }
162 
163 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
164 {
165 	struct xenvif *vif = netdev_priv(dev);
166 	struct xenvif_queue *queue = NULL;
167 	unsigned int num_queues = vif->num_queues;
168 	u16 index;
169 	struct xenvif_rx_cb *cb;
170 
171 	BUG_ON(skb->dev != dev);
172 
173 	/* Drop the packet if queues are not set up */
174 	if (num_queues < 1)
175 		goto drop;
176 
177 	/* Obtain the queue to be used to transmit this packet */
178 	index = skb_get_queue_mapping(skb);
179 	if (index >= num_queues) {
180 		pr_warn_ratelimited("Invalid queue %hu for packet on interface %s\n.",
181 				    index, vif->dev->name);
182 		index %= num_queues;
183 	}
184 	queue = &vif->queues[index];
185 
186 	/* Drop the packet if queue is not ready */
187 	if (queue->task == NULL ||
188 	    queue->dealloc_task == NULL ||
189 	    !xenvif_schedulable(vif))
190 		goto drop;
191 
192 	if (vif->multicast_control && skb->pkt_type == PACKET_MULTICAST) {
193 		struct ethhdr *eth = (struct ethhdr *)skb->data;
194 
195 		if (!xenvif_mcast_match(vif, eth->h_dest))
196 			goto drop;
197 	}
198 
199 	cb = XENVIF_RX_CB(skb);
200 	cb->expires = jiffies + vif->drain_timeout;
201 
202 	/* If there is no hash algorithm configured then make sure there
203 	 * is no hash information in the socket buffer otherwise it
204 	 * would be incorrectly forwarded to the frontend.
205 	 */
206 	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
207 		skb_clear_hash(skb);
208 
209 	xenvif_rx_queue_tail(queue, skb);
210 	xenvif_kick_thread(queue);
211 
212 	return NETDEV_TX_OK;
213 
214  drop:
215 	vif->dev->stats.tx_dropped++;
216 	dev_kfree_skb(skb);
217 	return NETDEV_TX_OK;
218 }
219 
220 static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
221 {
222 	struct xenvif *vif = netdev_priv(dev);
223 	struct xenvif_queue *queue = NULL;
224 	unsigned int num_queues = vif->num_queues;
225 	unsigned long rx_bytes = 0;
226 	unsigned long rx_packets = 0;
227 	unsigned long tx_bytes = 0;
228 	unsigned long tx_packets = 0;
229 	unsigned int index;
230 
231 	if (vif->queues == NULL)
232 		goto out;
233 
234 	/* Aggregate tx and rx stats from each queue */
235 	for (index = 0; index < num_queues; ++index) {
236 		queue = &vif->queues[index];
237 		rx_bytes += queue->stats.rx_bytes;
238 		rx_packets += queue->stats.rx_packets;
239 		tx_bytes += queue->stats.tx_bytes;
240 		tx_packets += queue->stats.tx_packets;
241 	}
242 
243 out:
244 	vif->dev->stats.rx_bytes = rx_bytes;
245 	vif->dev->stats.rx_packets = rx_packets;
246 	vif->dev->stats.tx_bytes = tx_bytes;
247 	vif->dev->stats.tx_packets = tx_packets;
248 
249 	return &vif->dev->stats;
250 }
251 
252 static void xenvif_up(struct xenvif *vif)
253 {
254 	struct xenvif_queue *queue = NULL;
255 	unsigned int num_queues = vif->num_queues;
256 	unsigned int queue_index;
257 
258 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
259 		queue = &vif->queues[queue_index];
260 		napi_enable(&queue->napi);
261 		enable_irq(queue->tx_irq);
262 		if (queue->tx_irq != queue->rx_irq)
263 			enable_irq(queue->rx_irq);
264 		xenvif_napi_schedule_or_enable_events(queue);
265 	}
266 }
267 
268 static void xenvif_down(struct xenvif *vif)
269 {
270 	struct xenvif_queue *queue = NULL;
271 	unsigned int num_queues = vif->num_queues;
272 	unsigned int queue_index;
273 
274 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
275 		queue = &vif->queues[queue_index];
276 		disable_irq(queue->tx_irq);
277 		if (queue->tx_irq != queue->rx_irq)
278 			disable_irq(queue->rx_irq);
279 		napi_disable(&queue->napi);
280 		del_timer_sync(&queue->credit_timeout);
281 	}
282 }
283 
284 static int xenvif_open(struct net_device *dev)
285 {
286 	struct xenvif *vif = netdev_priv(dev);
287 	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
288 		xenvif_up(vif);
289 	netif_tx_start_all_queues(dev);
290 	return 0;
291 }
292 
293 static int xenvif_close(struct net_device *dev)
294 {
295 	struct xenvif *vif = netdev_priv(dev);
296 	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
297 		xenvif_down(vif);
298 	netif_tx_stop_all_queues(dev);
299 	return 0;
300 }
301 
302 static int xenvif_change_mtu(struct net_device *dev, int mtu)
303 {
304 	struct xenvif *vif = netdev_priv(dev);
305 	int max = vif->can_sg ? ETH_MAX_MTU - VLAN_ETH_HLEN : ETH_DATA_LEN;
306 
307 	if (mtu > max)
308 		return -EINVAL;
309 	dev->mtu = mtu;
310 	return 0;
311 }
312 
313 static netdev_features_t xenvif_fix_features(struct net_device *dev,
314 	netdev_features_t features)
315 {
316 	struct xenvif *vif = netdev_priv(dev);
317 
318 	if (!vif->can_sg)
319 		features &= ~NETIF_F_SG;
320 	if (~(vif->gso_mask) & GSO_BIT(TCPV4))
321 		features &= ~NETIF_F_TSO;
322 	if (~(vif->gso_mask) & GSO_BIT(TCPV6))
323 		features &= ~NETIF_F_TSO6;
324 	if (!vif->ip_csum)
325 		features &= ~NETIF_F_IP_CSUM;
326 	if (!vif->ipv6_csum)
327 		features &= ~NETIF_F_IPV6_CSUM;
328 
329 	return features;
330 }
331 
332 static const struct xenvif_stat {
333 	char name[ETH_GSTRING_LEN];
334 	u16 offset;
335 } xenvif_stats[] = {
336 	{
337 		"rx_gso_checksum_fixup",
338 		offsetof(struct xenvif_stats, rx_gso_checksum_fixup)
339 	},
340 	/* If (sent != success + fail), there are probably packets never
341 	 * freed up properly!
342 	 */
343 	{
344 		"tx_zerocopy_sent",
345 		offsetof(struct xenvif_stats, tx_zerocopy_sent),
346 	},
347 	{
348 		"tx_zerocopy_success",
349 		offsetof(struct xenvif_stats, tx_zerocopy_success),
350 	},
351 	{
352 		"tx_zerocopy_fail",
353 		offsetof(struct xenvif_stats, tx_zerocopy_fail)
354 	},
355 	/* Number of packets exceeding MAX_SKB_FRAG slots. You should use
356 	 * a guest with the same MAX_SKB_FRAG
357 	 */
358 	{
359 		"tx_frag_overflow",
360 		offsetof(struct xenvif_stats, tx_frag_overflow)
361 	},
362 };
363 
364 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
365 {
366 	switch (string_set) {
367 	case ETH_SS_STATS:
368 		return ARRAY_SIZE(xenvif_stats);
369 	default:
370 		return -EINVAL;
371 	}
372 }
373 
374 static void xenvif_get_ethtool_stats(struct net_device *dev,
375 				     struct ethtool_stats *stats, u64 * data)
376 {
377 	struct xenvif *vif = netdev_priv(dev);
378 	unsigned int num_queues = vif->num_queues;
379 	int i;
380 	unsigned int queue_index;
381 
382 	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
383 		unsigned long accum = 0;
384 		for (queue_index = 0; queue_index < num_queues; ++queue_index) {
385 			void *vif_stats = &vif->queues[queue_index].stats;
386 			accum += *(unsigned long *)(vif_stats + xenvif_stats[i].offset);
387 		}
388 		data[i] = accum;
389 	}
390 }
391 
392 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
393 {
394 	int i;
395 
396 	switch (stringset) {
397 	case ETH_SS_STATS:
398 		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
399 			memcpy(data + i * ETH_GSTRING_LEN,
400 			       xenvif_stats[i].name, ETH_GSTRING_LEN);
401 		break;
402 	}
403 }
404 
405 static const struct ethtool_ops xenvif_ethtool_ops = {
406 	.get_link	= ethtool_op_get_link,
407 
408 	.get_sset_count = xenvif_get_sset_count,
409 	.get_ethtool_stats = xenvif_get_ethtool_stats,
410 	.get_strings = xenvif_get_strings,
411 };
412 
413 static const struct net_device_ops xenvif_netdev_ops = {
414 	.ndo_select_queue = xenvif_select_queue,
415 	.ndo_start_xmit	= xenvif_start_xmit,
416 	.ndo_get_stats	= xenvif_get_stats,
417 	.ndo_open	= xenvif_open,
418 	.ndo_stop	= xenvif_close,
419 	.ndo_change_mtu	= xenvif_change_mtu,
420 	.ndo_fix_features = xenvif_fix_features,
421 	.ndo_set_mac_address = eth_mac_addr,
422 	.ndo_validate_addr   = eth_validate_addr,
423 };
424 
425 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
426 			    unsigned int handle)
427 {
428 	int err;
429 	struct net_device *dev;
430 	struct xenvif *vif;
431 	char name[IFNAMSIZ] = {};
432 
433 	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
434 	/* Allocate a netdev with the max. supported number of queues.
435 	 * When the guest selects the desired number, it will be updated
436 	 * via netif_set_real_num_*_queues().
437 	 */
438 	dev = alloc_netdev_mq(sizeof(struct xenvif), name, NET_NAME_UNKNOWN,
439 			      ether_setup, xenvif_max_queues);
440 	if (dev == NULL) {
441 		pr_warn("Could not allocate netdev for %s\n", name);
442 		return ERR_PTR(-ENOMEM);
443 	}
444 
445 	SET_NETDEV_DEV(dev, parent);
446 
447 	vif = netdev_priv(dev);
448 
449 	vif->domid  = domid;
450 	vif->handle = handle;
451 	vif->can_sg = 1;
452 	vif->ip_csum = 1;
453 	vif->dev = dev;
454 	vif->disabled = false;
455 	vif->drain_timeout = msecs_to_jiffies(rx_drain_timeout_msecs);
456 	vif->stall_timeout = msecs_to_jiffies(rx_stall_timeout_msecs);
457 
458 	/* Start out with no queues. */
459 	vif->queues = NULL;
460 	vif->num_queues = 0;
461 
462 	spin_lock_init(&vif->lock);
463 	INIT_LIST_HEAD(&vif->fe_mcast_addr);
464 
465 	dev->netdev_ops	= &xenvif_netdev_ops;
466 	dev->hw_features = NETIF_F_SG |
467 		NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
468 		NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_FRAGLIST;
469 	dev->features = dev->hw_features | NETIF_F_RXCSUM;
470 	dev->ethtool_ops = &xenvif_ethtool_ops;
471 
472 	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
473 
474 	dev->min_mtu = 0;
475 	dev->max_mtu = ETH_MAX_MTU - VLAN_ETH_HLEN;
476 
477 	/*
478 	 * Initialise a dummy MAC address. We choose the numerically
479 	 * largest non-broadcast address to prevent the address getting
480 	 * stolen by an Ethernet bridge for STP purposes.
481 	 * (FE:FF:FF:FF:FF:FF)
482 	 */
483 	eth_broadcast_addr(dev->dev_addr);
484 	dev->dev_addr[0] &= ~0x01;
485 
486 	netif_carrier_off(dev);
487 
488 	err = register_netdev(dev);
489 	if (err) {
490 		netdev_warn(dev, "Could not register device: err=%d\n", err);
491 		free_netdev(dev);
492 		return ERR_PTR(err);
493 	}
494 
495 	netdev_dbg(dev, "Successfully created xenvif\n");
496 
497 	__module_get(THIS_MODULE);
498 
499 	return vif;
500 }
501 
502 int xenvif_init_queue(struct xenvif_queue *queue)
503 {
504 	int err, i;
505 
506 	queue->credit_bytes = queue->remaining_credit = ~0UL;
507 	queue->credit_usec  = 0UL;
508 	init_timer(&queue->credit_timeout);
509 	queue->credit_timeout.function = xenvif_tx_credit_callback;
510 	queue->credit_window_start = get_jiffies_64();
511 
512 	queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES;
513 
514 	skb_queue_head_init(&queue->rx_queue);
515 	skb_queue_head_init(&queue->tx_queue);
516 
517 	queue->pending_cons = 0;
518 	queue->pending_prod = MAX_PENDING_REQS;
519 	for (i = 0; i < MAX_PENDING_REQS; ++i)
520 		queue->pending_ring[i] = i;
521 
522 	spin_lock_init(&queue->callback_lock);
523 	spin_lock_init(&queue->response_lock);
524 
525 	/* If ballooning is disabled, this will consume real memory, so you
526 	 * better enable it. The long term solution would be to use just a
527 	 * bunch of valid page descriptors, without dependency on ballooning
528 	 */
529 	err = gnttab_alloc_pages(MAX_PENDING_REQS,
530 				 queue->mmap_pages);
531 	if (err) {
532 		netdev_err(queue->vif->dev, "Could not reserve mmap_pages\n");
533 		return -ENOMEM;
534 	}
535 
536 	for (i = 0; i < MAX_PENDING_REQS; i++) {
537 		queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
538 			{ .callback = xenvif_zerocopy_callback,
539 			  .ctx = NULL,
540 			  .desc = i };
541 		queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
542 	}
543 
544 	return 0;
545 }
546 
547 void xenvif_carrier_on(struct xenvif *vif)
548 {
549 	rtnl_lock();
550 	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
551 		dev_set_mtu(vif->dev, ETH_DATA_LEN);
552 	netdev_update_features(vif->dev);
553 	set_bit(VIF_STATUS_CONNECTED, &vif->status);
554 	if (netif_running(vif->dev))
555 		xenvif_up(vif);
556 	rtnl_unlock();
557 }
558 
559 int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref,
560 			unsigned int evtchn)
561 {
562 	struct net_device *dev = vif->dev;
563 	void *addr;
564 	struct xen_netif_ctrl_sring *shared;
565 	int err;
566 
567 	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
568 				     &ring_ref, 1, &addr);
569 	if (err)
570 		goto err;
571 
572 	shared = (struct xen_netif_ctrl_sring *)addr;
573 	BACK_RING_INIT(&vif->ctrl, shared, XEN_PAGE_SIZE);
574 
575 	err = bind_interdomain_evtchn_to_irq(vif->domid, evtchn);
576 	if (err < 0)
577 		goto err_unmap;
578 
579 	vif->ctrl_irq = err;
580 
581 	xenvif_init_hash(vif);
582 
583 	err = request_threaded_irq(vif->ctrl_irq, NULL, xenvif_ctrl_irq_fn,
584 				   IRQF_ONESHOT, "xen-netback-ctrl", vif);
585 	if (err) {
586 		pr_warn("Could not setup irq handler for %s\n", dev->name);
587 		goto err_deinit;
588 	}
589 
590 	return 0;
591 
592 err_deinit:
593 	xenvif_deinit_hash(vif);
594 	unbind_from_irqhandler(vif->ctrl_irq, vif);
595 	vif->ctrl_irq = 0;
596 
597 err_unmap:
598 	xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
599 				vif->ctrl.sring);
600 	vif->ctrl.sring = NULL;
601 
602 err:
603 	return err;
604 }
605 
606 int xenvif_connect_data(struct xenvif_queue *queue,
607 			unsigned long tx_ring_ref,
608 			unsigned long rx_ring_ref,
609 			unsigned int tx_evtchn,
610 			unsigned int rx_evtchn)
611 {
612 	struct task_struct *task;
613 	int err = -ENOMEM;
614 
615 	BUG_ON(queue->tx_irq);
616 	BUG_ON(queue->task);
617 	BUG_ON(queue->dealloc_task);
618 
619 	err = xenvif_map_frontend_data_rings(queue, tx_ring_ref,
620 					     rx_ring_ref);
621 	if (err < 0)
622 		goto err;
623 
624 	init_waitqueue_head(&queue->wq);
625 	init_waitqueue_head(&queue->dealloc_wq);
626 	atomic_set(&queue->inflight_packets, 0);
627 
628 	netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
629 			XENVIF_NAPI_WEIGHT);
630 
631 	if (tx_evtchn == rx_evtchn) {
632 		/* feature-split-event-channels == 0 */
633 		err = bind_interdomain_evtchn_to_irqhandler(
634 			queue->vif->domid, tx_evtchn, xenvif_interrupt, 0,
635 			queue->name, queue);
636 		if (err < 0)
637 			goto err_unmap;
638 		queue->tx_irq = queue->rx_irq = err;
639 		disable_irq(queue->tx_irq);
640 	} else {
641 		/* feature-split-event-channels == 1 */
642 		snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
643 			 "%s-tx", queue->name);
644 		err = bind_interdomain_evtchn_to_irqhandler(
645 			queue->vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
646 			queue->tx_irq_name, queue);
647 		if (err < 0)
648 			goto err_unmap;
649 		queue->tx_irq = err;
650 		disable_irq(queue->tx_irq);
651 
652 		snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
653 			 "%s-rx", queue->name);
654 		err = bind_interdomain_evtchn_to_irqhandler(
655 			queue->vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
656 			queue->rx_irq_name, queue);
657 		if (err < 0)
658 			goto err_tx_unbind;
659 		queue->rx_irq = err;
660 		disable_irq(queue->rx_irq);
661 	}
662 
663 	queue->stalled = true;
664 
665 	task = kthread_create(xenvif_kthread_guest_rx,
666 			      (void *)queue, "%s-guest-rx", queue->name);
667 	if (IS_ERR(task)) {
668 		pr_warn("Could not allocate kthread for %s\n", queue->name);
669 		err = PTR_ERR(task);
670 		goto err_rx_unbind;
671 	}
672 	queue->task = task;
673 	get_task_struct(task);
674 
675 	task = kthread_create(xenvif_dealloc_kthread,
676 			      (void *)queue, "%s-dealloc", queue->name);
677 	if (IS_ERR(task)) {
678 		pr_warn("Could not allocate kthread for %s\n", queue->name);
679 		err = PTR_ERR(task);
680 		goto err_rx_unbind;
681 	}
682 	queue->dealloc_task = task;
683 
684 	wake_up_process(queue->task);
685 	wake_up_process(queue->dealloc_task);
686 
687 	return 0;
688 
689 err_rx_unbind:
690 	unbind_from_irqhandler(queue->rx_irq, queue);
691 	queue->rx_irq = 0;
692 err_tx_unbind:
693 	unbind_from_irqhandler(queue->tx_irq, queue);
694 	queue->tx_irq = 0;
695 err_unmap:
696 	xenvif_unmap_frontend_data_rings(queue);
697 	netif_napi_del(&queue->napi);
698 err:
699 	module_put(THIS_MODULE);
700 	return err;
701 }
702 
703 void xenvif_carrier_off(struct xenvif *vif)
704 {
705 	struct net_device *dev = vif->dev;
706 
707 	rtnl_lock();
708 	if (test_and_clear_bit(VIF_STATUS_CONNECTED, &vif->status)) {
709 		netif_carrier_off(dev); /* discard queued packets */
710 		if (netif_running(dev))
711 			xenvif_down(vif);
712 	}
713 	rtnl_unlock();
714 }
715 
716 void xenvif_disconnect_data(struct xenvif *vif)
717 {
718 	struct xenvif_queue *queue = NULL;
719 	unsigned int num_queues = vif->num_queues;
720 	unsigned int queue_index;
721 
722 	xenvif_carrier_off(vif);
723 
724 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
725 		queue = &vif->queues[queue_index];
726 
727 		netif_napi_del(&queue->napi);
728 
729 		if (queue->task) {
730 			kthread_stop(queue->task);
731 			put_task_struct(queue->task);
732 			queue->task = NULL;
733 		}
734 
735 		if (queue->dealloc_task) {
736 			kthread_stop(queue->dealloc_task);
737 			queue->dealloc_task = NULL;
738 		}
739 
740 		if (queue->tx_irq) {
741 			if (queue->tx_irq == queue->rx_irq)
742 				unbind_from_irqhandler(queue->tx_irq, queue);
743 			else {
744 				unbind_from_irqhandler(queue->tx_irq, queue);
745 				unbind_from_irqhandler(queue->rx_irq, queue);
746 			}
747 			queue->tx_irq = 0;
748 		}
749 
750 		xenvif_unmap_frontend_data_rings(queue);
751 	}
752 
753 	xenvif_mcast_addr_list_free(vif);
754 }
755 
756 void xenvif_disconnect_ctrl(struct xenvif *vif)
757 {
758 	if (vif->ctrl_irq) {
759 		xenvif_deinit_hash(vif);
760 		unbind_from_irqhandler(vif->ctrl_irq, vif);
761 		vif->ctrl_irq = 0;
762 	}
763 
764 	if (vif->ctrl.sring) {
765 		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
766 					vif->ctrl.sring);
767 		vif->ctrl.sring = NULL;
768 	}
769 }
770 
771 /* Reverse the relevant parts of xenvif_init_queue().
772  * Used for queue teardown from xenvif_free(), and on the
773  * error handling paths in xenbus.c:connect().
774  */
775 void xenvif_deinit_queue(struct xenvif_queue *queue)
776 {
777 	gnttab_free_pages(MAX_PENDING_REQS, queue->mmap_pages);
778 }
779 
780 void xenvif_free(struct xenvif *vif)
781 {
782 	struct xenvif_queue *queues = vif->queues;
783 	unsigned int num_queues = vif->num_queues;
784 	unsigned int queue_index;
785 
786 	unregister_netdev(vif->dev);
787 	free_netdev(vif->dev);
788 
789 	for (queue_index = 0; queue_index < num_queues; ++queue_index)
790 		xenvif_deinit_queue(&queues[queue_index]);
791 	vfree(queues);
792 
793 	module_put(THIS_MODULE);
794 }
795