1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * virtio transport for vsock
4 *
5 * Copyright (C) 2013-2015 Red Hat, Inc.
6 * Author: Asias He <asias@redhat.com>
7 *         Stefan Hajnoczi <stefanha@redhat.com>
8 *
9 * Some of the code is take from Gerd Hoffmann <kraxel@redhat.com>'s
10 * early virtio-vsock proof-of-concept bits.
11 */
12#include <linux/spinlock.h>
13#include <linux/module.h>
14#include <linux/list.h>
15#include <linux/atomic.h>
16#include <linux/virtio.h>
17#include <linux/virtio_ids.h>
18#include <linux/virtio_config.h>
19#include <linux/virtio_vsock.h>
20#include <net/sock.h>
21#include <linux/mutex.h>
22#include <net/af_vsock.h>
23
24static struct workqueue_struct *virtio_vsock_workqueue;
25static struct virtio_vsock __rcu *the_virtio_vsock;
26static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
27static struct virtio_transport virtio_transport; /* forward declaration */
28
29struct virtio_vsock {
30	struct virtio_device *vdev;
31	struct virtqueue *vqs[VSOCK_VQ_MAX];
32
33	/* Virtqueue processing is deferred to a workqueue */
34	struct work_struct tx_work;
35	struct work_struct rx_work;
36	struct work_struct event_work;
37
38	/* The following fields are protected by tx_lock.  vqs[VSOCK_VQ_TX]
39	 * must be accessed with tx_lock held.
40	 */
41	struct mutex tx_lock;
42	bool tx_run;
43
44	struct work_struct send_pkt_work;
45	struct sk_buff_head send_pkt_queue;
46
47	atomic_t queued_replies;
48
49	/* The following fields are protected by rx_lock.  vqs[VSOCK_VQ_RX]
50	 * must be accessed with rx_lock held.
51	 */
52	struct mutex rx_lock;
53	bool rx_run;
54	int rx_buf_nr;
55	int rx_buf_max_nr;
56
57	/* The following fields are protected by event_lock.
58	 * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
59	 */
60	struct mutex event_lock;
61	bool event_run;
62	struct virtio_vsock_event event_list[8];
63
64	u32 guest_cid;
65	bool seqpacket_allow;
66};
67
68static u32 virtio_transport_get_local_cid(void)
69{
70	struct virtio_vsock *vsock;
71	u32 ret;
72
73	rcu_read_lock();
74	vsock = rcu_dereference(the_virtio_vsock);
75	if (!vsock) {
76		ret = VMADDR_CID_ANY;
77		goto out_rcu;
78	}
79
80	ret = vsock->guest_cid;
81out_rcu:
82	rcu_read_unlock();
83	return ret;
84}
85
86static void
87virtio_transport_send_pkt_work(struct work_struct *work)
88{
89	struct virtio_vsock *vsock =
90		container_of(work, struct virtio_vsock, send_pkt_work);
91	struct virtqueue *vq;
92	bool added = false;
93	bool restart_rx = false;
94
95	mutex_lock(&vsock->tx_lock);
96
97	if (!vsock->tx_run)
98		goto out;
99
100	vq = vsock->vqs[VSOCK_VQ_TX];
101
102	for (;;) {
103		struct scatterlist hdr, buf, *sgs[2];
104		int ret, in_sg = 0, out_sg = 0;
105		struct sk_buff *skb;
106		bool reply;
107
108		skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue);
109		if (!skb)
110			break;
111
112		virtio_transport_deliver_tap_pkt(skb);
113		reply = virtio_vsock_skb_reply(skb);
114
115		sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
116		sgs[out_sg++] = &hdr;
117		if (skb->len > 0) {
118			sg_init_one(&buf, skb->data, skb->len);
119			sgs[out_sg++] = &buf;
120		}
121
122		ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
123		/* Usually this means that there is no more space available in
124		 * the vq
125		 */
126		if (ret < 0) {
127			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
128			break;
129		}
130
131		if (reply) {
132			struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
133			int val;
134
135			val = atomic_dec_return(&vsock->queued_replies);
136
137			/* Do we now have resources to resume rx processing? */
138			if (val + 1 == virtqueue_get_vring_size(rx_vq))
139				restart_rx = true;
140		}
141
142		added = true;
143	}
144
145	if (added)
146		virtqueue_kick(vq);
147
148out:
149	mutex_unlock(&vsock->tx_lock);
150
151	if (restart_rx)
152		queue_work(virtio_vsock_workqueue, &vsock->rx_work);
153}
154
155static int
156virtio_transport_send_pkt(struct sk_buff *skb)
157{
158	struct virtio_vsock_hdr *hdr;
159	struct virtio_vsock *vsock;
160	int len = skb->len;
161
162	hdr = virtio_vsock_hdr(skb);
163
164	rcu_read_lock();
165	vsock = rcu_dereference(the_virtio_vsock);
166	if (!vsock) {
167		kfree_skb(skb);
168		len = -ENODEV;
169		goto out_rcu;
170	}
171
172	if (le64_to_cpu(hdr->dst_cid) == vsock->guest_cid) {
173		kfree_skb(skb);
174		len = -ENODEV;
175		goto out_rcu;
176	}
177
178	if (virtio_vsock_skb_reply(skb))
179		atomic_inc(&vsock->queued_replies);
180
181	virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);
182	queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
183
184out_rcu:
185	rcu_read_unlock();
186	return len;
187}
188
189static int
190virtio_transport_cancel_pkt(struct vsock_sock *vsk)
191{
192	struct virtio_vsock *vsock;
193	int cnt = 0, ret;
194
195	rcu_read_lock();
196	vsock = rcu_dereference(the_virtio_vsock);
197	if (!vsock) {
198		ret = -ENODEV;
199		goto out_rcu;
200	}
201
202	cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue);
203
204	if (cnt) {
205		struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
206		int new_cnt;
207
208		new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
209		if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
210		    new_cnt < virtqueue_get_vring_size(rx_vq))
211			queue_work(virtio_vsock_workqueue, &vsock->rx_work);
212	}
213
214	ret = 0;
215
216out_rcu:
217	rcu_read_unlock();
218	return ret;
219}
220
221static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
222{
223	int total_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM;
224	struct scatterlist pkt, *p;
225	struct virtqueue *vq;
226	struct sk_buff *skb;
227	int ret;
228
229	vq = vsock->vqs[VSOCK_VQ_RX];
230
231	do {
232		skb = virtio_vsock_alloc_skb(total_len, GFP_KERNEL);
233		if (!skb)
234			break;
235
236		memset(skb->head, 0, VIRTIO_VSOCK_SKB_HEADROOM);
237		sg_init_one(&pkt, virtio_vsock_hdr(skb), total_len);
238		p = &pkt;
239		ret = virtqueue_add_sgs(vq, &p, 0, 1, skb, GFP_KERNEL);
240		if (ret < 0) {
241			kfree_skb(skb);
242			break;
243		}
244
245		vsock->rx_buf_nr++;
246	} while (vq->num_free);
247	if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
248		vsock->rx_buf_max_nr = vsock->rx_buf_nr;
249	virtqueue_kick(vq);
250}
251
252static void virtio_transport_tx_work(struct work_struct *work)
253{
254	struct virtio_vsock *vsock =
255		container_of(work, struct virtio_vsock, tx_work);
256	struct virtqueue *vq;
257	bool added = false;
258
259	vq = vsock->vqs[VSOCK_VQ_TX];
260	mutex_lock(&vsock->tx_lock);
261
262	if (!vsock->tx_run)
263		goto out;
264
265	do {
266		struct sk_buff *skb;
267		unsigned int len;
268
269		virtqueue_disable_cb(vq);
270		while ((skb = virtqueue_get_buf(vq, &len)) != NULL) {
271			consume_skb(skb);
272			added = true;
273		}
274	} while (!virtqueue_enable_cb(vq));
275
276out:
277	mutex_unlock(&vsock->tx_lock);
278
279	if (added)
280		queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
281}
282
283/* Is there space left for replies to rx packets? */
284static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
285{
286	struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
287	int val;
288
289	smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
290	val = atomic_read(&vsock->queued_replies);
291
292	return val < virtqueue_get_vring_size(vq);
293}
294
295/* event_lock must be held */
296static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
297				       struct virtio_vsock_event *event)
298{
299	struct scatterlist sg;
300	struct virtqueue *vq;
301
302	vq = vsock->vqs[VSOCK_VQ_EVENT];
303
304	sg_init_one(&sg, event, sizeof(*event));
305
306	return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
307}
308
309/* event_lock must be held */
310static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
311{
312	size_t i;
313
314	for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
315		struct virtio_vsock_event *event = &vsock->event_list[i];
316
317		virtio_vsock_event_fill_one(vsock, event);
318	}
319
320	virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
321}
322
323static void virtio_vsock_reset_sock(struct sock *sk)
324{
325	/* vmci_transport.c doesn't take sk_lock here either.  At least we're
326	 * under vsock_table_lock so the sock cannot disappear while we're
327	 * executing.
328	 */
329
330	sk->sk_state = TCP_CLOSE;
331	sk->sk_err = ECONNRESET;
332	sk_error_report(sk);
333}
334
335static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
336{
337	struct virtio_device *vdev = vsock->vdev;
338	__le64 guest_cid;
339
340	vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
341			  &guest_cid, sizeof(guest_cid));
342	vsock->guest_cid = le64_to_cpu(guest_cid);
343}
344
345/* event_lock must be held */
346static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
347				      struct virtio_vsock_event *event)
348{
349	switch (le32_to_cpu(event->id)) {
350	case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
351		virtio_vsock_update_guest_cid(vsock);
352		vsock_for_each_connected_socket(&virtio_transport.transport,
353						virtio_vsock_reset_sock);
354		break;
355	}
356}
357
358static void virtio_transport_event_work(struct work_struct *work)
359{
360	struct virtio_vsock *vsock =
361		container_of(work, struct virtio_vsock, event_work);
362	struct virtqueue *vq;
363
364	vq = vsock->vqs[VSOCK_VQ_EVENT];
365
366	mutex_lock(&vsock->event_lock);
367
368	if (!vsock->event_run)
369		goto out;
370
371	do {
372		struct virtio_vsock_event *event;
373		unsigned int len;
374
375		virtqueue_disable_cb(vq);
376		while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
377			if (len == sizeof(*event))
378				virtio_vsock_event_handle(vsock, event);
379
380			virtio_vsock_event_fill_one(vsock, event);
381		}
382	} while (!virtqueue_enable_cb(vq));
383
384	virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
385out:
386	mutex_unlock(&vsock->event_lock);
387}
388
389static void virtio_vsock_event_done(struct virtqueue *vq)
390{
391	struct virtio_vsock *vsock = vq->vdev->priv;
392
393	if (!vsock)
394		return;
395	queue_work(virtio_vsock_workqueue, &vsock->event_work);
396}
397
398static void virtio_vsock_tx_done(struct virtqueue *vq)
399{
400	struct virtio_vsock *vsock = vq->vdev->priv;
401
402	if (!vsock)
403		return;
404	queue_work(virtio_vsock_workqueue, &vsock->tx_work);
405}
406
407static void virtio_vsock_rx_done(struct virtqueue *vq)
408{
409	struct virtio_vsock *vsock = vq->vdev->priv;
410
411	if (!vsock)
412		return;
413	queue_work(virtio_vsock_workqueue, &vsock->rx_work);
414}
415
416static bool virtio_transport_seqpacket_allow(u32 remote_cid);
417
418static struct virtio_transport virtio_transport = {
419	.transport = {
420		.module                   = THIS_MODULE,
421
422		.get_local_cid            = virtio_transport_get_local_cid,
423
424		.init                     = virtio_transport_do_socket_init,
425		.destruct                 = virtio_transport_destruct,
426		.release                  = virtio_transport_release,
427		.connect                  = virtio_transport_connect,
428		.shutdown                 = virtio_transport_shutdown,
429		.cancel_pkt               = virtio_transport_cancel_pkt,
430
431		.dgram_bind               = virtio_transport_dgram_bind,
432		.dgram_dequeue            = virtio_transport_dgram_dequeue,
433		.dgram_enqueue            = virtio_transport_dgram_enqueue,
434		.dgram_allow              = virtio_transport_dgram_allow,
435
436		.stream_dequeue           = virtio_transport_stream_dequeue,
437		.stream_enqueue           = virtio_transport_stream_enqueue,
438		.stream_has_data          = virtio_transport_stream_has_data,
439		.stream_has_space         = virtio_transport_stream_has_space,
440		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
441		.stream_is_active         = virtio_transport_stream_is_active,
442		.stream_allow             = virtio_transport_stream_allow,
443
444		.seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,
445		.seqpacket_enqueue        = virtio_transport_seqpacket_enqueue,
446		.seqpacket_allow          = virtio_transport_seqpacket_allow,
447		.seqpacket_has_data       = virtio_transport_seqpacket_has_data,
448
449		.notify_poll_in           = virtio_transport_notify_poll_in,
450		.notify_poll_out          = virtio_transport_notify_poll_out,
451		.notify_recv_init         = virtio_transport_notify_recv_init,
452		.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
453		.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
454		.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
455		.notify_send_init         = virtio_transport_notify_send_init,
456		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
457		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
458		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
459		.notify_buffer_size       = virtio_transport_notify_buffer_size,
460		.notify_set_rcvlowat      = virtio_transport_notify_set_rcvlowat,
461
462		.read_skb = virtio_transport_read_skb,
463	},
464
465	.send_pkt = virtio_transport_send_pkt,
466};
467
468static bool virtio_transport_seqpacket_allow(u32 remote_cid)
469{
470	struct virtio_vsock *vsock;
471	bool seqpacket_allow;
472
473	seqpacket_allow = false;
474	rcu_read_lock();
475	vsock = rcu_dereference(the_virtio_vsock);
476	if (vsock)
477		seqpacket_allow = vsock->seqpacket_allow;
478	rcu_read_unlock();
479
480	return seqpacket_allow;
481}
482
483static void virtio_transport_rx_work(struct work_struct *work)
484{
485	struct virtio_vsock *vsock =
486		container_of(work, struct virtio_vsock, rx_work);
487	struct virtqueue *vq;
488
489	vq = vsock->vqs[VSOCK_VQ_RX];
490
491	mutex_lock(&vsock->rx_lock);
492
493	if (!vsock->rx_run)
494		goto out;
495
496	do {
497		virtqueue_disable_cb(vq);
498		for (;;) {
499			struct sk_buff *skb;
500			unsigned int len;
501
502			if (!virtio_transport_more_replies(vsock)) {
503				/* Stop rx until the device processes already
504				 * pending replies.  Leave rx virtqueue
505				 * callbacks disabled.
506				 */
507				goto out;
508			}
509
510			skb = virtqueue_get_buf(vq, &len);
511			if (!skb)
512				break;
513
514			vsock->rx_buf_nr--;
515
516			/* Drop short/long packets */
517			if (unlikely(len < sizeof(struct virtio_vsock_hdr) ||
518				     len > virtio_vsock_skb_len(skb))) {
519				kfree_skb(skb);
520				continue;
521			}
522
523			virtio_vsock_skb_rx_put(skb);
524			virtio_transport_deliver_tap_pkt(skb);
525			virtio_transport_recv_pkt(&virtio_transport, skb);
526		}
527	} while (!virtqueue_enable_cb(vq));
528
529out:
530	if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
531		virtio_vsock_rx_fill(vsock);
532	mutex_unlock(&vsock->rx_lock);
533}
534
535static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
536{
537	struct virtio_device *vdev = vsock->vdev;
538	static const char * const names[] = {
539		"rx",
540		"tx",
541		"event",
542	};
543	vq_callback_t *callbacks[] = {
544		virtio_vsock_rx_done,
545		virtio_vsock_tx_done,
546		virtio_vsock_event_done,
547	};
548	int ret;
549
550	ret = virtio_find_vqs(vdev, VSOCK_VQ_MAX, vsock->vqs, callbacks, names,
551			      NULL);
552	if (ret < 0)
553		return ret;
554
555	virtio_vsock_update_guest_cid(vsock);
556
557	virtio_device_ready(vdev);
558
559	return 0;
560}
561
562static void virtio_vsock_vqs_start(struct virtio_vsock *vsock)
563{
564	mutex_lock(&vsock->tx_lock);
565	vsock->tx_run = true;
566	mutex_unlock(&vsock->tx_lock);
567
568	mutex_lock(&vsock->rx_lock);
569	virtio_vsock_rx_fill(vsock);
570	vsock->rx_run = true;
571	mutex_unlock(&vsock->rx_lock);
572
573	mutex_lock(&vsock->event_lock);
574	virtio_vsock_event_fill(vsock);
575	vsock->event_run = true;
576	mutex_unlock(&vsock->event_lock);
577
578	/* virtio_transport_send_pkt() can queue packets once
579	 * the_virtio_vsock is set, but they won't be processed until
580	 * vsock->tx_run is set to true. We queue vsock->send_pkt_work
581	 * when initialization finishes to send those packets queued
582	 * earlier.
583	 * We don't need to queue the other workers (rx, event) because
584	 * as long as we don't fill the queues with empty buffers, the
585	 * host can't send us any notification.
586	 */
587	queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
588}
589
590static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)
591{
592	struct virtio_device *vdev = vsock->vdev;
593	struct sk_buff *skb;
594
595	/* Reset all connected sockets when the VQs disappear */
596	vsock_for_each_connected_socket(&virtio_transport.transport,
597					virtio_vsock_reset_sock);
598
599	/* Stop all work handlers to make sure no one is accessing the device,
600	 * so we can safely call virtio_reset_device().
601	 */
602	mutex_lock(&vsock->rx_lock);
603	vsock->rx_run = false;
604	mutex_unlock(&vsock->rx_lock);
605
606	mutex_lock(&vsock->tx_lock);
607	vsock->tx_run = false;
608	mutex_unlock(&vsock->tx_lock);
609
610	mutex_lock(&vsock->event_lock);
611	vsock->event_run = false;
612	mutex_unlock(&vsock->event_lock);
613
614	/* Flush all device writes and interrupts, device will not use any
615	 * more buffers.
616	 */
617	virtio_reset_device(vdev);
618
619	mutex_lock(&vsock->rx_lock);
620	while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
621		kfree_skb(skb);
622	mutex_unlock(&vsock->rx_lock);
623
624	mutex_lock(&vsock->tx_lock);
625	while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
626		kfree_skb(skb);
627	mutex_unlock(&vsock->tx_lock);
628
629	virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue);
630
631	/* Delete virtqueues and flush outstanding callbacks if any */
632	vdev->config->del_vqs(vdev);
633}
634
635static int virtio_vsock_probe(struct virtio_device *vdev)
636{
637	struct virtio_vsock *vsock = NULL;
638	int ret;
639
640	ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
641	if (ret)
642		return ret;
643
644	/* Only one virtio-vsock device per guest is supported */
645	if (rcu_dereference_protected(the_virtio_vsock,
646				lockdep_is_held(&the_virtio_vsock_mutex))) {
647		ret = -EBUSY;
648		goto out;
649	}
650
651	vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
652	if (!vsock) {
653		ret = -ENOMEM;
654		goto out;
655	}
656
657	vsock->vdev = vdev;
658
659	vsock->rx_buf_nr = 0;
660	vsock->rx_buf_max_nr = 0;
661	atomic_set(&vsock->queued_replies, 0);
662
663	mutex_init(&vsock->tx_lock);
664	mutex_init(&vsock->rx_lock);
665	mutex_init(&vsock->event_lock);
666	skb_queue_head_init(&vsock->send_pkt_queue);
667	INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
668	INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
669	INIT_WORK(&vsock->event_work, virtio_transport_event_work);
670	INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
671
672	if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
673		vsock->seqpacket_allow = true;
674
675	vdev->priv = vsock;
676
677	ret = virtio_vsock_vqs_init(vsock);
678	if (ret < 0)
679		goto out;
680
681	rcu_assign_pointer(the_virtio_vsock, vsock);
682	virtio_vsock_vqs_start(vsock);
683
684	mutex_unlock(&the_virtio_vsock_mutex);
685
686	return 0;
687
688out:
689	kfree(vsock);
690	mutex_unlock(&the_virtio_vsock_mutex);
691	return ret;
692}
693
694static void virtio_vsock_remove(struct virtio_device *vdev)
695{
696	struct virtio_vsock *vsock = vdev->priv;
697
698	mutex_lock(&the_virtio_vsock_mutex);
699
700	vdev->priv = NULL;
701	rcu_assign_pointer(the_virtio_vsock, NULL);
702	synchronize_rcu();
703
704	virtio_vsock_vqs_del(vsock);
705
706	/* Other works can be queued before 'config->del_vqs()', so we flush
707	 * all works before to free the vsock object to avoid use after free.
708	 */
709	flush_work(&vsock->rx_work);
710	flush_work(&vsock->tx_work);
711	flush_work(&vsock->event_work);
712	flush_work(&vsock->send_pkt_work);
713
714	mutex_unlock(&the_virtio_vsock_mutex);
715
716	kfree(vsock);
717}
718
719#ifdef CONFIG_PM_SLEEP
720static int virtio_vsock_freeze(struct virtio_device *vdev)
721{
722	struct virtio_vsock *vsock = vdev->priv;
723
724	mutex_lock(&the_virtio_vsock_mutex);
725
726	rcu_assign_pointer(the_virtio_vsock, NULL);
727	synchronize_rcu();
728
729	virtio_vsock_vqs_del(vsock);
730
731	mutex_unlock(&the_virtio_vsock_mutex);
732
733	return 0;
734}
735
736static int virtio_vsock_restore(struct virtio_device *vdev)
737{
738	struct virtio_vsock *vsock = vdev->priv;
739	int ret;
740
741	mutex_lock(&the_virtio_vsock_mutex);
742
743	/* Only one virtio-vsock device per guest is supported */
744	if (rcu_dereference_protected(the_virtio_vsock,
745				lockdep_is_held(&the_virtio_vsock_mutex))) {
746		ret = -EBUSY;
747		goto out;
748	}
749
750	ret = virtio_vsock_vqs_init(vsock);
751	if (ret < 0)
752		goto out;
753
754	rcu_assign_pointer(the_virtio_vsock, vsock);
755	virtio_vsock_vqs_start(vsock);
756
757out:
758	mutex_unlock(&the_virtio_vsock_mutex);
759	return ret;
760}
761#endif /* CONFIG_PM_SLEEP */
762
763static struct virtio_device_id id_table[] = {
764	{ VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
765	{ 0 },
766};
767
768static unsigned int features[] = {
769	VIRTIO_VSOCK_F_SEQPACKET
770};
771
772static struct virtio_driver virtio_vsock_driver = {
773	.feature_table = features,
774	.feature_table_size = ARRAY_SIZE(features),
775	.driver.name = KBUILD_MODNAME,
776	.driver.owner = THIS_MODULE,
777	.id_table = id_table,
778	.probe = virtio_vsock_probe,
779	.remove = virtio_vsock_remove,
780#ifdef CONFIG_PM_SLEEP
781	.freeze = virtio_vsock_freeze,
782	.restore = virtio_vsock_restore,
783#endif
784};
785
786static int __init virtio_vsock_init(void)
787{
788	int ret;
789
790	virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
791	if (!virtio_vsock_workqueue)
792		return -ENOMEM;
793
794	ret = vsock_core_register(&virtio_transport.transport,
795				  VSOCK_TRANSPORT_F_G2H);
796	if (ret)
797		goto out_wq;
798
799	ret = register_virtio_driver(&virtio_vsock_driver);
800	if (ret)
801		goto out_vci;
802
803	return 0;
804
805out_vci:
806	vsock_core_unregister(&virtio_transport.transport);
807out_wq:
808	destroy_workqueue(virtio_vsock_workqueue);
809	return ret;
810}
811
812static void __exit virtio_vsock_exit(void)
813{
814	unregister_virtio_driver(&virtio_vsock_driver);
815	vsock_core_unregister(&virtio_transport.transport);
816	destroy_workqueue(virtio_vsock_workqueue);
817}
818
819module_init(virtio_vsock_init);
820module_exit(virtio_vsock_exit);
821MODULE_LICENSE("GPL v2");
822MODULE_AUTHOR("Asias He");
823MODULE_DESCRIPTION("virtio transport for vsock");
824MODULE_DEVICE_TABLE(virtio, id_table);
825