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
24 static struct workqueue_struct *virtio_vsock_workqueue;
25 static struct virtio_vsock __rcu *the_virtio_vsock;
26 static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
27 static struct virtio_transport virtio_transport; /* forward declaration */
28
29 struct 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 /* These fields are used only in tx path in function
68 * 'virtio_transport_send_pkt_work()', so to save
69 * stack space in it, place both of them here. Each
70 * pointer from 'out_sgs' points to the corresponding
71 * element in 'out_bufs' - this is initialized in
72 * 'virtio_vsock_probe()'. Both fields are protected
73 * by 'tx_lock'. +1 is needed for packet header.
74 */
75 struct scatterlist *out_sgs[MAX_SKB_FRAGS + 1];
76 struct scatterlist out_bufs[MAX_SKB_FRAGS + 1];
77 };
78
79 static u32 virtio_transport_get_local_cid(void)
80 {
81 struct virtio_vsock *vsock;
82 u32 ret;
83
84 rcu_read_lock();
85 vsock = rcu_dereference(the_virtio_vsock);
86 if (!vsock) {
87 ret = VMADDR_CID_ANY;
88 goto out_rcu;
89 }
90
91 ret = vsock->guest_cid;
92 out_rcu:
93 rcu_read_unlock();
94 return ret;
95 }
96
97 static void
98 virtio_transport_send_pkt_work(struct work_struct *work)
99 {
100 struct virtio_vsock *vsock =
101 container_of(work, struct virtio_vsock, send_pkt_work);
102 struct virtqueue *vq;
103 bool added = false;
104 bool restart_rx = false;
105
106 mutex_lock(&vsock->tx_lock);
107
108 if (!vsock->tx_run)
109 goto out;
110
111 vq = vsock->vqs[VSOCK_VQ_TX];
112
113 for (;;) {
114 int ret, in_sg = 0, out_sg = 0;
115 struct scatterlist **sgs;
116 struct sk_buff *skb;
117 bool reply;
118
119 skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue);
120 if (!skb)
121 break;
122
123 reply = virtio_vsock_skb_reply(skb);
124 sgs = vsock->out_sgs;
125 sg_init_one(sgs[out_sg], virtio_vsock_hdr(skb),
126 sizeof(*virtio_vsock_hdr(skb)));
127 out_sg++;
128
129 if (!skb_is_nonlinear(skb)) {
130 if (skb->len > 0) {
131 sg_init_one(sgs[out_sg], skb->data, skb->len);
132 out_sg++;
133 }
134 } else {
135 struct skb_shared_info *si;
136 int i;
137
138 /* If skb is nonlinear, then its buffer must contain
139 * only header and nothing more. Data is stored in
140 * the fragged part.
141 */
142 WARN_ON_ONCE(skb_headroom(skb) != sizeof(*virtio_vsock_hdr(skb)));
143
144 si = skb_shinfo(skb);
145
146 for (i = 0; i < si->nr_frags; i++) {
147 skb_frag_t *skb_frag = &si->frags[i];
148 void *va;
149
150 /* We will use 'page_to_virt()' for the userspace page
151 * here, because virtio or dma-mapping layers will call
152 * 'virt_to_phys()' later to fill the buffer descriptor.
153 * We don't touch memory at "virtual" address of this page.
154 */
155 va = page_to_virt(skb_frag_page(skb_frag));
156 sg_init_one(sgs[out_sg],
157 va + skb_frag_off(skb_frag),
158 skb_frag_size(skb_frag));
159 out_sg++;
160 }
161 }
162
163 ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
164 /* Usually this means that there is no more space available in
165 * the vq
166 */
167 if (ret < 0) {
168 virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
169 break;
170 }
171
172 virtio_transport_deliver_tap_pkt(skb);
173
174 if (reply) {
175 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
176 int val;
177
178 val = atomic_dec_return(&vsock->queued_replies);
179
180 /* Do we now have resources to resume rx processing? */
181 if (val + 1 == virtqueue_get_vring_size(rx_vq))
182 restart_rx = true;
183 }
184
185 added = true;
186 }
187
188 if (added)
189 virtqueue_kick(vq);
190
191 out:
192 mutex_unlock(&vsock->tx_lock);
193
194 if (restart_rx)
195 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
196 }
197
198 static int
199 virtio_transport_send_pkt(struct sk_buff *skb)
200 {
201 struct virtio_vsock_hdr *hdr;
202 struct virtio_vsock *vsock;
203 int len = skb->len;
204
205 hdr = virtio_vsock_hdr(skb);
206
207 rcu_read_lock();
208 vsock = rcu_dereference(the_virtio_vsock);
209 if (!vsock) {
210 kfree_skb(skb);
211 len = -ENODEV;
212 goto out_rcu;
213 }
214
215 if (le64_to_cpu(hdr->dst_cid) == vsock->guest_cid) {
216 kfree_skb(skb);
217 len = -ENODEV;
218 goto out_rcu;
219 }
220
221 if (virtio_vsock_skb_reply(skb))
222 atomic_inc(&vsock->queued_replies);
223
224 virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);
225 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
226
227 out_rcu:
228 rcu_read_unlock();
229 return len;
230 }
231
232 static int
233 virtio_transport_cancel_pkt(struct vsock_sock *vsk)
234 {
235 struct virtio_vsock *vsock;
236 int cnt = 0, ret;
237
238 rcu_read_lock();
239 vsock = rcu_dereference(the_virtio_vsock);
240 if (!vsock) {
241 ret = -ENODEV;
242 goto out_rcu;
243 }
244
245 cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue);
246
247 if (cnt) {
248 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
249 int new_cnt;
250
251 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
252 if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
253 new_cnt < virtqueue_get_vring_size(rx_vq))
254 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
255 }
256
257 ret = 0;
258
259 out_rcu:
260 rcu_read_unlock();
261 return ret;
262 }
263
264 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
265 {
266 int total_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM;
267 struct scatterlist pkt, *p;
268 struct virtqueue *vq;
269 struct sk_buff *skb;
270 int ret;
271
272 vq = vsock->vqs[VSOCK_VQ_RX];
273
274 do {
275 skb = virtio_vsock_alloc_skb(total_len, GFP_KERNEL);
276 if (!skb)
277 break;
278
279 memset(skb->head, 0, VIRTIO_VSOCK_SKB_HEADROOM);
280 sg_init_one(&pkt, virtio_vsock_hdr(skb), total_len);
281 p = &pkt;
282 ret = virtqueue_add_sgs(vq, &p, 0, 1, skb, GFP_KERNEL);
283 if (ret < 0) {
284 kfree_skb(skb);
285 break;
286 }
287
288 vsock->rx_buf_nr++;
289 } while (vq->num_free);
290 if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
291 vsock->rx_buf_max_nr = vsock->rx_buf_nr;
292 virtqueue_kick(vq);
293 }
294
295 static void virtio_transport_tx_work(struct work_struct *work)
296 {
297 struct virtio_vsock *vsock =
298 container_of(work, struct virtio_vsock, tx_work);
299 struct virtqueue *vq;
300 bool added = false;
301
302 vq = vsock->vqs[VSOCK_VQ_TX];
303 mutex_lock(&vsock->tx_lock);
304
305 if (!vsock->tx_run)
306 goto out;
307
308 do {
309 struct sk_buff *skb;
310 unsigned int len;
311
312 virtqueue_disable_cb(vq);
313 while ((skb = virtqueue_get_buf(vq, &len)) != NULL) {
314 consume_skb(skb);
315 added = true;
316 }
317 } while (!virtqueue_enable_cb(vq));
318
319 out:
320 mutex_unlock(&vsock->tx_lock);
321
322 if (added)
323 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
324 }
325
326 /* Is there space left for replies to rx packets? */
327 static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
328 {
329 struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
330 int val;
331
332 smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
333 val = atomic_read(&vsock->queued_replies);
334
335 return val < virtqueue_get_vring_size(vq);
336 }
337
338 /* event_lock must be held */
339 static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
340 struct virtio_vsock_event *event)
341 {
342 struct scatterlist sg;
343 struct virtqueue *vq;
344
345 vq = vsock->vqs[VSOCK_VQ_EVENT];
346
347 sg_init_one(&sg, event, sizeof(*event));
348
349 return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
350 }
351
352 /* event_lock must be held */
353 static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
354 {
355 size_t i;
356
357 for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
358 struct virtio_vsock_event *event = &vsock->event_list[i];
359
360 virtio_vsock_event_fill_one(vsock, event);
361 }
362
363 virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
364 }
365
366 static void virtio_vsock_reset_sock(struct sock *sk)
367 {
368 /* vmci_transport.c doesn't take sk_lock here either. At least we're
369 * under vsock_table_lock so the sock cannot disappear while we're
370 * executing.
371 */
372
373 sk->sk_state = TCP_CLOSE;
374 sk->sk_err = ECONNRESET;
375 sk_error_report(sk);
376 }
377
378 static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
379 {
380 struct virtio_device *vdev = vsock->vdev;
381 __le64 guest_cid;
382
383 vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
384 &guest_cid, sizeof(guest_cid));
385 vsock->guest_cid = le64_to_cpu(guest_cid);
386 }
387
388 /* event_lock must be held */
389 static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
390 struct virtio_vsock_event *event)
391 {
392 switch (le32_to_cpu(event->id)) {
393 case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
394 virtio_vsock_update_guest_cid(vsock);
395 vsock_for_each_connected_socket(&virtio_transport.transport,
396 virtio_vsock_reset_sock);
397 break;
398 }
399 }
400
401 static void virtio_transport_event_work(struct work_struct *work)
402 {
403 struct virtio_vsock *vsock =
404 container_of(work, struct virtio_vsock, event_work);
405 struct virtqueue *vq;
406
407 vq = vsock->vqs[VSOCK_VQ_EVENT];
408
409 mutex_lock(&vsock->event_lock);
410
411 if (!vsock->event_run)
412 goto out;
413
414 do {
415 struct virtio_vsock_event *event;
416 unsigned int len;
417
418 virtqueue_disable_cb(vq);
419 while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
420 if (len == sizeof(*event))
421 virtio_vsock_event_handle(vsock, event);
422
423 virtio_vsock_event_fill_one(vsock, event);
424 }
425 } while (!virtqueue_enable_cb(vq));
426
427 virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
428 out:
429 mutex_unlock(&vsock->event_lock);
430 }
431
432 static void virtio_vsock_event_done(struct virtqueue *vq)
433 {
434 struct virtio_vsock *vsock = vq->vdev->priv;
435
436 if (!vsock)
437 return;
438 queue_work(virtio_vsock_workqueue, &vsock->event_work);
439 }
440
441 static void virtio_vsock_tx_done(struct virtqueue *vq)
442 {
443 struct virtio_vsock *vsock = vq->vdev->priv;
444
445 if (!vsock)
446 return;
447 queue_work(virtio_vsock_workqueue, &vsock->tx_work);
448 }
449
450 static void virtio_vsock_rx_done(struct virtqueue *vq)
451 {
452 struct virtio_vsock *vsock = vq->vdev->priv;
453
454 if (!vsock)
455 return;
456 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
457 }
458
459 static bool virtio_transport_can_msgzerocopy(int bufs_num)
460 {
461 struct virtio_vsock *vsock;
462 bool res = false;
463
464 rcu_read_lock();
465
466 vsock = rcu_dereference(the_virtio_vsock);
467 if (vsock) {
468 struct virtqueue *vq = vsock->vqs[VSOCK_VQ_TX];
469
470 /* Check that tx queue is large enough to keep whole
471 * data to send. This is needed, because when there is
472 * not enough free space in the queue, current skb to
473 * send will be reinserted to the head of tx list of
474 * the socket to retry transmission later, so if skb
475 * is bigger than whole queue, it will be reinserted
476 * again and again, thus blocking other skbs to be sent.
477 * Each page of the user provided buffer will be added
478 * as a single buffer to the tx virtqueue, so compare
479 * number of pages against maximum capacity of the queue.
480 */
481 if (bufs_num <= vq->num_max)
482 res = true;
483 }
484
485 rcu_read_unlock();
486
487 return res;
488 }
489
490 static bool virtio_transport_msgzerocopy_allow(void)
491 {
492 return true;
493 }
494
495 static bool virtio_transport_seqpacket_allow(u32 remote_cid);
496
497 static struct virtio_transport virtio_transport = {
498 .transport = {
499 .module = THIS_MODULE,
500
501 .get_local_cid = virtio_transport_get_local_cid,
502
503 .init = virtio_transport_do_socket_init,
504 .destruct = virtio_transport_destruct,
505 .release = virtio_transport_release,
506 .connect = virtio_transport_connect,
507 .shutdown = virtio_transport_shutdown,
508 .cancel_pkt = virtio_transport_cancel_pkt,
509
510 .dgram_bind = virtio_transport_dgram_bind,
511 .dgram_dequeue = virtio_transport_dgram_dequeue,
512 .dgram_enqueue = virtio_transport_dgram_enqueue,
513 .dgram_allow = virtio_transport_dgram_allow,
514
515 .stream_dequeue = virtio_transport_stream_dequeue,
516 .stream_enqueue = virtio_transport_stream_enqueue,
517 .stream_has_data = virtio_transport_stream_has_data,
518 .stream_has_space = virtio_transport_stream_has_space,
519 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat,
520 .stream_is_active = virtio_transport_stream_is_active,
521 .stream_allow = virtio_transport_stream_allow,
522
523 .seqpacket_dequeue = virtio_transport_seqpacket_dequeue,
524 .seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
525 .seqpacket_allow = virtio_transport_seqpacket_allow,
526 .seqpacket_has_data = virtio_transport_seqpacket_has_data,
527
528 .msgzerocopy_allow = virtio_transport_msgzerocopy_allow,
529
530 .notify_poll_in = virtio_transport_notify_poll_in,
531 .notify_poll_out = virtio_transport_notify_poll_out,
532 .notify_recv_init = virtio_transport_notify_recv_init,
533 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block,
534 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,
535 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
536 .notify_send_init = virtio_transport_notify_send_init,
537 .notify_send_pre_block = virtio_transport_notify_send_pre_block,
538 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,
539 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
540 .notify_buffer_size = virtio_transport_notify_buffer_size,
541 .notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat,
542
543 .read_skb = virtio_transport_read_skb,
544 },
545
546 .send_pkt = virtio_transport_send_pkt,
547 .can_msgzerocopy = virtio_transport_can_msgzerocopy,
548 };
549
550 static bool virtio_transport_seqpacket_allow(u32 remote_cid)
551 {
552 struct virtio_vsock *vsock;
553 bool seqpacket_allow;
554
555 seqpacket_allow = false;
556 rcu_read_lock();
557 vsock = rcu_dereference(the_virtio_vsock);
558 if (vsock)
559 seqpacket_allow = vsock->seqpacket_allow;
560 rcu_read_unlock();
561
562 return seqpacket_allow;
563 }
564
565 static void virtio_transport_rx_work(struct work_struct *work)
566 {
567 struct virtio_vsock *vsock =
568 container_of(work, struct virtio_vsock, rx_work);
569 struct virtqueue *vq;
570
571 vq = vsock->vqs[VSOCK_VQ_RX];
572
573 mutex_lock(&vsock->rx_lock);
574
575 if (!vsock->rx_run)
576 goto out;
577
578 do {
579 virtqueue_disable_cb(vq);
580 for (;;) {
581 struct sk_buff *skb;
582 unsigned int len;
583
584 if (!virtio_transport_more_replies(vsock)) {
585 /* Stop rx until the device processes already
586 * pending replies. Leave rx virtqueue
587 * callbacks disabled.
588 */
589 goto out;
590 }
591
592 skb = virtqueue_get_buf(vq, &len);
593 if (!skb)
594 break;
595
596 vsock->rx_buf_nr--;
597
598 /* Drop short/long packets */
599 if (unlikely(len < sizeof(struct virtio_vsock_hdr) ||
600 len > virtio_vsock_skb_len(skb))) {
601 kfree_skb(skb);
602 continue;
603 }
604
605 virtio_vsock_skb_rx_put(skb);
606 virtio_transport_deliver_tap_pkt(skb);
607 virtio_transport_recv_pkt(&virtio_transport, skb);
608 }
609 } while (!virtqueue_enable_cb(vq));
610
611 out:
612 if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
613 virtio_vsock_rx_fill(vsock);
614 mutex_unlock(&vsock->rx_lock);
615 }
616
617 static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
618 {
619 struct virtio_device *vdev = vsock->vdev;
620 struct virtqueue_info vqs_info[] = {
621 { "rx", virtio_vsock_rx_done },
622 { "tx", virtio_vsock_tx_done },
623 { "event", virtio_vsock_event_done },
624 };
625 int ret;
626
627 ret = virtio_find_vqs(vdev, VSOCK_VQ_MAX, vsock->vqs, vqs_info, NULL);
628 if (ret < 0)
629 return ret;
630
631 virtio_vsock_update_guest_cid(vsock);
632
633 virtio_device_ready(vdev);
634
635 return 0;
636 }
637
638 static void virtio_vsock_vqs_start(struct virtio_vsock *vsock)
639 {
640 mutex_lock(&vsock->tx_lock);
641 vsock->tx_run = true;
642 mutex_unlock(&vsock->tx_lock);
643
644 mutex_lock(&vsock->rx_lock);
645 virtio_vsock_rx_fill(vsock);
646 vsock->rx_run = true;
647 mutex_unlock(&vsock->rx_lock);
648
649 mutex_lock(&vsock->event_lock);
650 virtio_vsock_event_fill(vsock);
651 vsock->event_run = true;
652 mutex_unlock(&vsock->event_lock);
653
654 /* virtio_transport_send_pkt() can queue packets once
655 * the_virtio_vsock is set, but they won't be processed until
656 * vsock->tx_run is set to true. We queue vsock->send_pkt_work
657 * when initialization finishes to send those packets queued
658 * earlier.
659 * We don't need to queue the other workers (rx, event) because
660 * as long as we don't fill the queues with empty buffers, the
661 * host can't send us any notification.
662 */
663 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
664 }
665
666 static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)
667 {
668 struct virtio_device *vdev = vsock->vdev;
669 struct sk_buff *skb;
670
671 /* Reset all connected sockets when the VQs disappear */
672 vsock_for_each_connected_socket(&virtio_transport.transport,
673 virtio_vsock_reset_sock);
674
675 /* Stop all work handlers to make sure no one is accessing the device,
676 * so we can safely call virtio_reset_device().
677 */
678 mutex_lock(&vsock->rx_lock);
679 vsock->rx_run = false;
680 mutex_unlock(&vsock->rx_lock);
681
682 mutex_lock(&vsock->tx_lock);
683 vsock->tx_run = false;
684 mutex_unlock(&vsock->tx_lock);
685
686 mutex_lock(&vsock->event_lock);
687 vsock->event_run = false;
688 mutex_unlock(&vsock->event_lock);
689
690 /* Flush all device writes and interrupts, device will not use any
691 * more buffers.
692 */
693 virtio_reset_device(vdev);
694
695 mutex_lock(&vsock->rx_lock);
696 while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
697 kfree_skb(skb);
698 mutex_unlock(&vsock->rx_lock);
699
700 mutex_lock(&vsock->tx_lock);
701 while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
702 kfree_skb(skb);
703 mutex_unlock(&vsock->tx_lock);
704
705 virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue);
706
707 /* Delete virtqueues and flush outstanding callbacks if any */
708 vdev->config->del_vqs(vdev);
709 }
710
711 static int virtio_vsock_probe(struct virtio_device *vdev)
712 {
713 struct virtio_vsock *vsock = NULL;
714 int ret;
715 int i;
716
717 ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
718 if (ret)
719 return ret;
720
721 /* Only one virtio-vsock device per guest is supported */
722 if (rcu_dereference_protected(the_virtio_vsock,
723 lockdep_is_held(&the_virtio_vsock_mutex))) {
724 ret = -EBUSY;
725 goto out;
726 }
727
728 vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
729 if (!vsock) {
730 ret = -ENOMEM;
731 goto out;
732 }
733
734 vsock->vdev = vdev;
735
736 vsock->rx_buf_nr = 0;
737 vsock->rx_buf_max_nr = 0;
738 atomic_set(&vsock->queued_replies, 0);
739
740 mutex_init(&vsock->tx_lock);
741 mutex_init(&vsock->rx_lock);
742 mutex_init(&vsock->event_lock);
743 skb_queue_head_init(&vsock->send_pkt_queue);
744 INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
745 INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
746 INIT_WORK(&vsock->event_work, virtio_transport_event_work);
747 INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
748
749 if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
750 vsock->seqpacket_allow = true;
751
752 vdev->priv = vsock;
753
754 ret = virtio_vsock_vqs_init(vsock);
755 if (ret < 0)
756 goto out;
757
758 for (i = 0; i < ARRAY_SIZE(vsock->out_sgs); i++)
759 vsock->out_sgs[i] = &vsock->out_bufs[i];
760
761 rcu_assign_pointer(the_virtio_vsock, vsock);
762 virtio_vsock_vqs_start(vsock);
763
764 mutex_unlock(&the_virtio_vsock_mutex);
765
766 return 0;
767
768 out:
769 kfree(vsock);
770 mutex_unlock(&the_virtio_vsock_mutex);
771 return ret;
772 }
773
774 static void virtio_vsock_remove(struct virtio_device *vdev)
775 {
776 struct virtio_vsock *vsock = vdev->priv;
777
778 mutex_lock(&the_virtio_vsock_mutex);
779
780 vdev->priv = NULL;
781 rcu_assign_pointer(the_virtio_vsock, NULL);
782 synchronize_rcu();
783
784 virtio_vsock_vqs_del(vsock);
785
786 /* Other works can be queued before 'config->del_vqs()', so we flush
787 * all works before to free the vsock object to avoid use after free.
788 */
789 flush_work(&vsock->rx_work);
790 flush_work(&vsock->tx_work);
791 flush_work(&vsock->event_work);
792 flush_work(&vsock->send_pkt_work);
793
794 mutex_unlock(&the_virtio_vsock_mutex);
795
796 kfree(vsock);
797 }
798
799 #ifdef CONFIG_PM_SLEEP
800 static int virtio_vsock_freeze(struct virtio_device *vdev)
801 {
802 struct virtio_vsock *vsock = vdev->priv;
803
804 mutex_lock(&the_virtio_vsock_mutex);
805
806 rcu_assign_pointer(the_virtio_vsock, NULL);
807 synchronize_rcu();
808
809 virtio_vsock_vqs_del(vsock);
810
811 mutex_unlock(&the_virtio_vsock_mutex);
812
813 return 0;
814 }
815
816 static int virtio_vsock_restore(struct virtio_device *vdev)
817 {
818 struct virtio_vsock *vsock = vdev->priv;
819 int ret;
820
821 mutex_lock(&the_virtio_vsock_mutex);
822
823 /* Only one virtio-vsock device per guest is supported */
824 if (rcu_dereference_protected(the_virtio_vsock,
825 lockdep_is_held(&the_virtio_vsock_mutex))) {
826 ret = -EBUSY;
827 goto out;
828 }
829
830 ret = virtio_vsock_vqs_init(vsock);
831 if (ret < 0)
832 goto out;
833
834 rcu_assign_pointer(the_virtio_vsock, vsock);
835 virtio_vsock_vqs_start(vsock);
836
837 out:
838 mutex_unlock(&the_virtio_vsock_mutex);
839 return ret;
840 }
841 #endif /* CONFIG_PM_SLEEP */
842
843 static struct virtio_device_id id_table[] = {
844 { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
845 { 0 },
846 };
847
848 static unsigned int features[] = {
849 VIRTIO_VSOCK_F_SEQPACKET
850 };
851
852 static struct virtio_driver virtio_vsock_driver = {
853 .feature_table = features,
854 .feature_table_size = ARRAY_SIZE(features),
855 .driver.name = KBUILD_MODNAME,
856 .id_table = id_table,
857 .probe = virtio_vsock_probe,
858 .remove = virtio_vsock_remove,
859 #ifdef CONFIG_PM_SLEEP
860 .freeze = virtio_vsock_freeze,
861 .restore = virtio_vsock_restore,
862 #endif
863 };
864
865 static int __init virtio_vsock_init(void)
866 {
867 int ret;
868
869 virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
870 if (!virtio_vsock_workqueue)
871 return -ENOMEM;
872
873 ret = vsock_core_register(&virtio_transport.transport,
874 VSOCK_TRANSPORT_F_G2H);
875 if (ret)
876 goto out_wq;
877
878 ret = register_virtio_driver(&virtio_vsock_driver);
879 if (ret)
880 goto out_vci;
881
882 return 0;
883
884 out_vci:
885 vsock_core_unregister(&virtio_transport.transport);
886 out_wq:
887 destroy_workqueue(virtio_vsock_workqueue);
888 return ret;
889 }
890
891 static void __exit virtio_vsock_exit(void)
892 {
893 unregister_virtio_driver(&virtio_vsock_driver);
894 vsock_core_unregister(&virtio_transport.transport);
895 destroy_workqueue(virtio_vsock_workqueue);
896 }
897
898 module_init(virtio_vsock_init);
899 module_exit(virtio_vsock_exit);
900 MODULE_LICENSE("GPL v2");
901 MODULE_AUTHOR("Asias He");
902 MODULE_DESCRIPTION("virtio transport for vsock");
903 MODULE_DEVICE_TABLE(virtio, id_table);
904
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