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 /* 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
79static 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;
92out_rcu:
93 rcu_read_unlock();
94 return ret;
95}
96
97static void
98virtio_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(list: &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(frag: skb_frag),
158 skb_frag_size(frag: skb_frag));
159 out_sg++;
160 }
161 }
162
163 ret = virtqueue_add_sgs(vq, sgs, out_sgs: out_sg, in_sgs: in_sg, data: 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(list: &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(v: &vsock->queued_replies);
179
180 /* Do we now have resources to resume rx processing? */
181 if (val + 1 == virtqueue_get_vring_size(vq: rx_vq))
182 restart_rx = true;
183 }
184
185 added = true;
186 }
187
188 if (added)
189 virtqueue_kick(vq);
190
191out:
192 mutex_unlock(lock: &vsock->tx_lock);
193
194 if (restart_rx)
195 queue_work(wq: virtio_vsock_workqueue, work: &vsock->rx_work);
196}
197
198static int
199virtio_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(v: &vsock->queued_replies);
223
224 virtio_vsock_skb_queue_tail(list: &vsock->send_pkt_queue, skb);
225 queue_work(wq: virtio_vsock_workqueue, work: &vsock->send_pkt_work);
226
227out_rcu:
228 rcu_read_unlock();
229 return len;
230}
231
232static int
233virtio_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, list: &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(i: cnt, v: &vsock->queued_replies);
252 if (new_cnt + cnt >= virtqueue_get_vring_size(vq: rx_vq) &&
253 new_cnt < virtqueue_get_vring_size(vq: rx_vq))
254 queue_work(wq: virtio_vsock_workqueue, work: &vsock->rx_work);
255 }
256
257 ret = 0;
258
259out_rcu:
260 rcu_read_unlock();
261 return ret;
262}
263
264static 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(size: 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, sgs: &p, out_sgs: 0, in_sgs: 1, data: 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
295static 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: &len)) != NULL) {
314 consume_skb(skb);
315 added = true;
316 }
317 } while (!virtqueue_enable_cb(vq));
318
319out:
320 mutex_unlock(lock: &vsock->tx_lock);
321
322 if (added)
323 queue_work(wq: virtio_vsock_workqueue, work: &vsock->send_pkt_work);
324}
325
326/* Is there space left for replies to rx packets? */
327static 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(v: &vsock->queued_replies);
334
335 return val < virtqueue_get_vring_size(vq);
336}
337
338/* event_lock must be held */
339static 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: &sg, num: 1, data: event, GFP_KERNEL);
350}
351
352/* event_lock must be held */
353static 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(vq: vsock->vqs[VSOCK_VQ_EVENT]);
364}
365
366static 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
378static 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 */
389static 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(transport: &virtio_transport.transport,
396 fn: virtio_vsock_reset_sock);
397 break;
398 }
399}
400
401static 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: &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(vq: vsock->vqs[VSOCK_VQ_EVENT]);
428out:
429 mutex_unlock(lock: &vsock->event_lock);
430}
431
432static 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(wq: virtio_vsock_workqueue, work: &vsock->event_work);
439}
440
441static 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(wq: virtio_vsock_workqueue, work: &vsock->tx_work);
448}
449
450static 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(wq: virtio_vsock_workqueue, work: &vsock->rx_work);
457}
458
459static 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
490static bool virtio_transport_msgzerocopy_allow(void)
491{
492 return true;
493}
494
495static bool virtio_transport_seqpacket_allow(u32 remote_cid);
496
497static 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
550static 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
565static 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: &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(t: &virtio_transport, skb);
608 }
609 } while (!virtqueue_enable_cb(vq));
610
611out:
612 if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
613 virtio_vsock_rx_fill(vsock);
614 mutex_unlock(lock: &vsock->rx_lock);
615}
616
617static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
618{
619 struct virtio_device *vdev = vsock->vdev;
620 static const char * const names[] = {
621 "rx",
622 "tx",
623 "event",
624 };
625 vq_callback_t *callbacks[] = {
626 virtio_vsock_rx_done,
627 virtio_vsock_tx_done,
628 virtio_vsock_event_done,
629 };
630 int ret;
631
632 ret = virtio_find_vqs(vdev, nvqs: VSOCK_VQ_MAX, vqs: vsock->vqs, callbacks, names,
633 NULL);
634 if (ret < 0)
635 return ret;
636
637 virtio_vsock_update_guest_cid(vsock);
638
639 virtio_device_ready(dev: vdev);
640
641 return 0;
642}
643
644static void virtio_vsock_vqs_start(struct virtio_vsock *vsock)
645{
646 mutex_lock(&vsock->tx_lock);
647 vsock->tx_run = true;
648 mutex_unlock(lock: &vsock->tx_lock);
649
650 mutex_lock(&vsock->rx_lock);
651 virtio_vsock_rx_fill(vsock);
652 vsock->rx_run = true;
653 mutex_unlock(lock: &vsock->rx_lock);
654
655 mutex_lock(&vsock->event_lock);
656 virtio_vsock_event_fill(vsock);
657 vsock->event_run = true;
658 mutex_unlock(lock: &vsock->event_lock);
659
660 /* virtio_transport_send_pkt() can queue packets once
661 * the_virtio_vsock is set, but they won't be processed until
662 * vsock->tx_run is set to true. We queue vsock->send_pkt_work
663 * when initialization finishes to send those packets queued
664 * earlier.
665 * We don't need to queue the other workers (rx, event) because
666 * as long as we don't fill the queues with empty buffers, the
667 * host can't send us any notification.
668 */
669 queue_work(wq: virtio_vsock_workqueue, work: &vsock->send_pkt_work);
670}
671
672static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)
673{
674 struct virtio_device *vdev = vsock->vdev;
675 struct sk_buff *skb;
676
677 /* Reset all connected sockets when the VQs disappear */
678 vsock_for_each_connected_socket(transport: &virtio_transport.transport,
679 fn: virtio_vsock_reset_sock);
680
681 /* Stop all work handlers to make sure no one is accessing the device,
682 * so we can safely call virtio_reset_device().
683 */
684 mutex_lock(&vsock->rx_lock);
685 vsock->rx_run = false;
686 mutex_unlock(lock: &vsock->rx_lock);
687
688 mutex_lock(&vsock->tx_lock);
689 vsock->tx_run = false;
690 mutex_unlock(lock: &vsock->tx_lock);
691
692 mutex_lock(&vsock->event_lock);
693 vsock->event_run = false;
694 mutex_unlock(lock: &vsock->event_lock);
695
696 /* Flush all device writes and interrupts, device will not use any
697 * more buffers.
698 */
699 virtio_reset_device(dev: vdev);
700
701 mutex_lock(&vsock->rx_lock);
702 while ((skb = virtqueue_detach_unused_buf(vq: vsock->vqs[VSOCK_VQ_RX])))
703 kfree_skb(skb);
704 mutex_unlock(lock: &vsock->rx_lock);
705
706 mutex_lock(&vsock->tx_lock);
707 while ((skb = virtqueue_detach_unused_buf(vq: vsock->vqs[VSOCK_VQ_TX])))
708 kfree_skb(skb);
709 mutex_unlock(lock: &vsock->tx_lock);
710
711 virtio_vsock_skb_queue_purge(list: &vsock->send_pkt_queue);
712
713 /* Delete virtqueues and flush outstanding callbacks if any */
714 vdev->config->del_vqs(vdev);
715}
716
717static int virtio_vsock_probe(struct virtio_device *vdev)
718{
719 struct virtio_vsock *vsock = NULL;
720 int ret;
721 int i;
722
723 ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
724 if (ret)
725 return ret;
726
727 /* Only one virtio-vsock device per guest is supported */
728 if (rcu_dereference_protected(the_virtio_vsock,
729 lockdep_is_held(&the_virtio_vsock_mutex))) {
730 ret = -EBUSY;
731 goto out;
732 }
733
734 vsock = kzalloc(size: sizeof(*vsock), GFP_KERNEL);
735 if (!vsock) {
736 ret = -ENOMEM;
737 goto out;
738 }
739
740 vsock->vdev = vdev;
741
742 vsock->rx_buf_nr = 0;
743 vsock->rx_buf_max_nr = 0;
744 atomic_set(v: &vsock->queued_replies, i: 0);
745
746 mutex_init(&vsock->tx_lock);
747 mutex_init(&vsock->rx_lock);
748 mutex_init(&vsock->event_lock);
749 skb_queue_head_init(list: &vsock->send_pkt_queue);
750 INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
751 INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
752 INIT_WORK(&vsock->event_work, virtio_transport_event_work);
753 INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
754
755 if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
756 vsock->seqpacket_allow = true;
757
758 vdev->priv = vsock;
759
760 ret = virtio_vsock_vqs_init(vsock);
761 if (ret < 0)
762 goto out;
763
764 for (i = 0; i < ARRAY_SIZE(vsock->out_sgs); i++)
765 vsock->out_sgs[i] = &vsock->out_bufs[i];
766
767 rcu_assign_pointer(the_virtio_vsock, vsock);
768 virtio_vsock_vqs_start(vsock);
769
770 mutex_unlock(lock: &the_virtio_vsock_mutex);
771
772 return 0;
773
774out:
775 kfree(objp: vsock);
776 mutex_unlock(lock: &the_virtio_vsock_mutex);
777 return ret;
778}
779
780static void virtio_vsock_remove(struct virtio_device *vdev)
781{
782 struct virtio_vsock *vsock = vdev->priv;
783
784 mutex_lock(&the_virtio_vsock_mutex);
785
786 vdev->priv = NULL;
787 rcu_assign_pointer(the_virtio_vsock, NULL);
788 synchronize_rcu();
789
790 virtio_vsock_vqs_del(vsock);
791
792 /* Other works can be queued before 'config->del_vqs()', so we flush
793 * all works before to free the vsock object to avoid use after free.
794 */
795 flush_work(work: &vsock->rx_work);
796 flush_work(work: &vsock->tx_work);
797 flush_work(work: &vsock->event_work);
798 flush_work(work: &vsock->send_pkt_work);
799
800 mutex_unlock(lock: &the_virtio_vsock_mutex);
801
802 kfree(objp: vsock);
803}
804
805#ifdef CONFIG_PM_SLEEP
806static int virtio_vsock_freeze(struct virtio_device *vdev)
807{
808 struct virtio_vsock *vsock = vdev->priv;
809
810 mutex_lock(&the_virtio_vsock_mutex);
811
812 rcu_assign_pointer(the_virtio_vsock, NULL);
813 synchronize_rcu();
814
815 virtio_vsock_vqs_del(vsock);
816
817 mutex_unlock(lock: &the_virtio_vsock_mutex);
818
819 return 0;
820}
821
822static int virtio_vsock_restore(struct virtio_device *vdev)
823{
824 struct virtio_vsock *vsock = vdev->priv;
825 int ret;
826
827 mutex_lock(&the_virtio_vsock_mutex);
828
829 /* Only one virtio-vsock device per guest is supported */
830 if (rcu_dereference_protected(the_virtio_vsock,
831 lockdep_is_held(&the_virtio_vsock_mutex))) {
832 ret = -EBUSY;
833 goto out;
834 }
835
836 ret = virtio_vsock_vqs_init(vsock);
837 if (ret < 0)
838 goto out;
839
840 rcu_assign_pointer(the_virtio_vsock, vsock);
841 virtio_vsock_vqs_start(vsock);
842
843out:
844 mutex_unlock(lock: &the_virtio_vsock_mutex);
845 return ret;
846}
847#endif /* CONFIG_PM_SLEEP */
848
849static struct virtio_device_id id_table[] = {
850 { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
851 { 0 },
852};
853
854static unsigned int features[] = {
855 VIRTIO_VSOCK_F_SEQPACKET
856};
857
858static struct virtio_driver virtio_vsock_driver = {
859 .feature_table = features,
860 .feature_table_size = ARRAY_SIZE(features),
861 .driver.name = KBUILD_MODNAME,
862 .driver.owner = THIS_MODULE,
863 .id_table = id_table,
864 .probe = virtio_vsock_probe,
865 .remove = virtio_vsock_remove,
866#ifdef CONFIG_PM_SLEEP
867 .freeze = virtio_vsock_freeze,
868 .restore = virtio_vsock_restore,
869#endif
870};
871
872static int __init virtio_vsock_init(void)
873{
874 int ret;
875
876 virtio_vsock_workqueue = alloc_workqueue(fmt: "virtio_vsock", flags: 0, max_active: 0);
877 if (!virtio_vsock_workqueue)
878 return -ENOMEM;
879
880 ret = vsock_core_register(t: &virtio_transport.transport,
881 VSOCK_TRANSPORT_F_G2H);
882 if (ret)
883 goto out_wq;
884
885 ret = register_virtio_driver(&virtio_vsock_driver);
886 if (ret)
887 goto out_vci;
888
889 return 0;
890
891out_vci:
892 vsock_core_unregister(t: &virtio_transport.transport);
893out_wq:
894 destroy_workqueue(wq: virtio_vsock_workqueue);
895 return ret;
896}
897
898static void __exit virtio_vsock_exit(void)
899{
900 unregister_virtio_driver(drv: &virtio_vsock_driver);
901 vsock_core_unregister(t: &virtio_transport.transport);
902 destroy_workqueue(wq: virtio_vsock_workqueue);
903}
904
905module_init(virtio_vsock_init);
906module_exit(virtio_vsock_exit);
907MODULE_LICENSE("GPL v2");
908MODULE_AUTHOR("Asias He");
909MODULE_DESCRIPTION("virtio transport for vsock");
910MODULE_DEVICE_TABLE(virtio, id_table);
911

source code of linux/net/vmw_vsock/virtio_transport.c