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
virtio_transport_get_local_cid(void)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
virtio_transport_send_pkt_work(struct work_struct * work)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 virtio_transport_deliver_tap_pkt(skb);
124 reply = virtio_vsock_skb_reply(skb);
125 sgs = vsock->out_sgs;
126 sg_init_one(sgs[out_sg], virtio_vsock_hdr(skb),
127 sizeof(*virtio_vsock_hdr(skb)));
128 out_sg++;
129
130 if (!skb_is_nonlinear(skb)) {
131 if (skb->len > 0) {
132 sg_init_one(sgs[out_sg], skb->data, skb->len);
133 out_sg++;
134 }
135 } else {
136 struct skb_shared_info *si;
137 int i;
138
139 /* If skb is nonlinear, then its buffer must contain
140 * only header and nothing more. Data is stored in
141 * the fragged part.
142 */
143 WARN_ON_ONCE(skb_headroom(skb) != sizeof(*virtio_vsock_hdr(skb)));
144
145 si = skb_shinfo(skb);
146
147 for (i = 0; i < si->nr_frags; i++) {
148 skb_frag_t *skb_frag = &si->frags[i];
149 void *va;
150
151 /* We will use 'page_to_virt()' for the userspace page
152 * here, because virtio or dma-mapping layers will call
153 * 'virt_to_phys()' later to fill the buffer descriptor.
154 * We don't touch memory at "virtual" address of this page.
155 */
156 va = page_to_virt(skb_frag_page(skb_frag));
157 sg_init_one(sgs[out_sg],
158 va + skb_frag_off(skb_frag),
159 skb_frag_size(skb_frag));
160 out_sg++;
161 }
162 }
163
164 ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
165 /* Usually this means that there is no more space available in
166 * the vq
167 */
168 if (ret < 0) {
169 virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
170 break;
171 }
172
173 if (reply) {
174 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
175 int val;
176
177 val = atomic_dec_return(&vsock->queued_replies);
178
179 /* Do we now have resources to resume rx processing? */
180 if (val + 1 == virtqueue_get_vring_size(rx_vq))
181 restart_rx = true;
182 }
183
184 added = true;
185 }
186
187 if (added)
188 virtqueue_kick(vq);
189
190 out:
191 mutex_unlock(&vsock->tx_lock);
192
193 if (restart_rx)
194 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
195 }
196
197 static int
virtio_transport_send_pkt(struct sk_buff * skb)198 virtio_transport_send_pkt(struct sk_buff *skb)
199 {
200 struct virtio_vsock_hdr *hdr;
201 struct virtio_vsock *vsock;
202 int len = skb->len;
203
204 hdr = virtio_vsock_hdr(skb);
205
206 rcu_read_lock();
207 vsock = rcu_dereference(the_virtio_vsock);
208 if (!vsock) {
209 kfree_skb(skb);
210 len = -ENODEV;
211 goto out_rcu;
212 }
213
214 if (le64_to_cpu(hdr->dst_cid) == vsock->guest_cid) {
215 kfree_skb(skb);
216 len = -ENODEV;
217 goto out_rcu;
218 }
219
220 if (virtio_vsock_skb_reply(skb))
221 atomic_inc(&vsock->queued_replies);
222
223 virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);
224 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
225
226 out_rcu:
227 rcu_read_unlock();
228 return len;
229 }
230
231 static int
virtio_transport_cancel_pkt(struct vsock_sock * vsk)232 virtio_transport_cancel_pkt(struct vsock_sock *vsk)
233 {
234 struct virtio_vsock *vsock;
235 int cnt = 0, ret;
236
237 rcu_read_lock();
238 vsock = rcu_dereference(the_virtio_vsock);
239 if (!vsock) {
240 ret = -ENODEV;
241 goto out_rcu;
242 }
243
244 cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue);
245
246 if (cnt) {
247 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
248 int new_cnt;
249
250 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
251 if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
252 new_cnt < virtqueue_get_vring_size(rx_vq))
253 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
254 }
255
256 ret = 0;
257
258 out_rcu:
259 rcu_read_unlock();
260 return ret;
261 }
262
virtio_vsock_rx_fill(struct virtio_vsock * vsock)263 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
264 {
265 int total_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM;
266 struct scatterlist pkt, *p;
267 struct virtqueue *vq;
268 struct sk_buff *skb;
269 int ret;
270
271 vq = vsock->vqs[VSOCK_VQ_RX];
272
273 do {
274 skb = virtio_vsock_alloc_skb(total_len, GFP_KERNEL);
275 if (!skb)
276 break;
277
278 memset(skb->head, 0, VIRTIO_VSOCK_SKB_HEADROOM);
279 sg_init_one(&pkt, virtio_vsock_hdr(skb), total_len);
280 p = &pkt;
281 ret = virtqueue_add_sgs(vq, &p, 0, 1, skb, GFP_KERNEL);
282 if (ret < 0) {
283 kfree_skb(skb);
284 break;
285 }
286
287 vsock->rx_buf_nr++;
288 } while (vq->num_free);
289 if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
290 vsock->rx_buf_max_nr = vsock->rx_buf_nr;
291 virtqueue_kick(vq);
292 }
293
virtio_transport_tx_work(struct work_struct * work)294 static void virtio_transport_tx_work(struct work_struct *work)
295 {
296 struct virtio_vsock *vsock =
297 container_of(work, struct virtio_vsock, tx_work);
298 struct virtqueue *vq;
299 bool added = false;
300
301 vq = vsock->vqs[VSOCK_VQ_TX];
302 mutex_lock(&vsock->tx_lock);
303
304 if (!vsock->tx_run)
305 goto out;
306
307 do {
308 struct sk_buff *skb;
309 unsigned int len;
310
311 virtqueue_disable_cb(vq);
312 while ((skb = virtqueue_get_buf(vq, &len)) != NULL) {
313 consume_skb(skb);
314 added = true;
315 }
316 } while (!virtqueue_enable_cb(vq));
317
318 out:
319 mutex_unlock(&vsock->tx_lock);
320
321 if (added)
322 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
323 }
324
325 /* Is there space left for replies to rx packets? */
virtio_transport_more_replies(struct virtio_vsock * vsock)326 static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
327 {
328 struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
329 int val;
330
331 smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
332 val = atomic_read(&vsock->queued_replies);
333
334 return val < virtqueue_get_vring_size(vq);
335 }
336
337 /* event_lock must be held */
virtio_vsock_event_fill_one(struct virtio_vsock * vsock,struct virtio_vsock_event * event)338 static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
339 struct virtio_vsock_event *event)
340 {
341 struct scatterlist sg;
342 struct virtqueue *vq;
343
344 vq = vsock->vqs[VSOCK_VQ_EVENT];
345
346 sg_init_one(&sg, event, sizeof(*event));
347
348 return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
349 }
350
351 /* event_lock must be held */
virtio_vsock_event_fill(struct virtio_vsock * vsock)352 static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
353 {
354 size_t i;
355
356 for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
357 struct virtio_vsock_event *event = &vsock->event_list[i];
358
359 virtio_vsock_event_fill_one(vsock, event);
360 }
361
362 virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
363 }
364
virtio_vsock_reset_sock(struct sock * sk)365 static void virtio_vsock_reset_sock(struct sock *sk)
366 {
367 /* vmci_transport.c doesn't take sk_lock here either. At least we're
368 * under vsock_table_lock so the sock cannot disappear while we're
369 * executing.
370 */
371
372 sk->sk_state = TCP_CLOSE;
373 sk->sk_err = ECONNRESET;
374 sk_error_report(sk);
375 }
376
virtio_vsock_update_guest_cid(struct virtio_vsock * vsock)377 static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
378 {
379 struct virtio_device *vdev = vsock->vdev;
380 __le64 guest_cid;
381
382 vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
383 &guest_cid, sizeof(guest_cid));
384 vsock->guest_cid = le64_to_cpu(guest_cid);
385 }
386
387 /* event_lock must be held */
virtio_vsock_event_handle(struct virtio_vsock * vsock,struct virtio_vsock_event * event)388 static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
389 struct virtio_vsock_event *event)
390 {
391 switch (le32_to_cpu(event->id)) {
392 case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
393 virtio_vsock_update_guest_cid(vsock);
394 vsock_for_each_connected_socket(&virtio_transport.transport,
395 virtio_vsock_reset_sock);
396 break;
397 }
398 }
399
virtio_transport_event_work(struct work_struct * work)400 static void virtio_transport_event_work(struct work_struct *work)
401 {
402 struct virtio_vsock *vsock =
403 container_of(work, struct virtio_vsock, event_work);
404 struct virtqueue *vq;
405
406 vq = vsock->vqs[VSOCK_VQ_EVENT];
407
408 mutex_lock(&vsock->event_lock);
409
410 if (!vsock->event_run)
411 goto out;
412
413 do {
414 struct virtio_vsock_event *event;
415 unsigned int len;
416
417 virtqueue_disable_cb(vq);
418 while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
419 if (len == sizeof(*event))
420 virtio_vsock_event_handle(vsock, event);
421
422 virtio_vsock_event_fill_one(vsock, event);
423 }
424 } while (!virtqueue_enable_cb(vq));
425
426 virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
427 out:
428 mutex_unlock(&vsock->event_lock);
429 }
430
virtio_vsock_event_done(struct virtqueue * vq)431 static void virtio_vsock_event_done(struct virtqueue *vq)
432 {
433 struct virtio_vsock *vsock = vq->vdev->priv;
434
435 if (!vsock)
436 return;
437 queue_work(virtio_vsock_workqueue, &vsock->event_work);
438 }
439
virtio_vsock_tx_done(struct virtqueue * vq)440 static void virtio_vsock_tx_done(struct virtqueue *vq)
441 {
442 struct virtio_vsock *vsock = vq->vdev->priv;
443
444 if (!vsock)
445 return;
446 queue_work(virtio_vsock_workqueue, &vsock->tx_work);
447 }
448
virtio_vsock_rx_done(struct virtqueue * vq)449 static void virtio_vsock_rx_done(struct virtqueue *vq)
450 {
451 struct virtio_vsock *vsock = vq->vdev->priv;
452
453 if (!vsock)
454 return;
455 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
456 }
457
virtio_transport_can_msgzerocopy(int bufs_num)458 static bool virtio_transport_can_msgzerocopy(int bufs_num)
459 {
460 struct virtio_vsock *vsock;
461 bool res = false;
462
463 rcu_read_lock();
464
465 vsock = rcu_dereference(the_virtio_vsock);
466 if (vsock) {
467 struct virtqueue *vq = vsock->vqs[VSOCK_VQ_TX];
468
469 /* Check that tx queue is large enough to keep whole
470 * data to send. This is needed, because when there is
471 * not enough free space in the queue, current skb to
472 * send will be reinserted to the head of tx list of
473 * the socket to retry transmission later, so if skb
474 * is bigger than whole queue, it will be reinserted
475 * again and again, thus blocking other skbs to be sent.
476 * Each page of the user provided buffer will be added
477 * as a single buffer to the tx virtqueue, so compare
478 * number of pages against maximum capacity of the queue.
479 */
480 if (bufs_num <= vq->num_max)
481 res = true;
482 }
483
484 rcu_read_unlock();
485
486 return res;
487 }
488
virtio_transport_msgzerocopy_allow(void)489 static bool virtio_transport_msgzerocopy_allow(void)
490 {
491 return true;
492 }
493
494 static bool virtio_transport_seqpacket_allow(u32 remote_cid);
495
496 static struct virtio_transport virtio_transport = {
497 .transport = {
498 .module = THIS_MODULE,
499
500 .get_local_cid = virtio_transport_get_local_cid,
501
502 .init = virtio_transport_do_socket_init,
503 .destruct = virtio_transport_destruct,
504 .release = virtio_transport_release,
505 .connect = virtio_transport_connect,
506 .shutdown = virtio_transport_shutdown,
507 .cancel_pkt = virtio_transport_cancel_pkt,
508
509 .dgram_bind = virtio_transport_dgram_bind,
510 .dgram_dequeue = virtio_transport_dgram_dequeue,
511 .dgram_enqueue = virtio_transport_dgram_enqueue,
512 .dgram_allow = virtio_transport_dgram_allow,
513
514 .stream_dequeue = virtio_transport_stream_dequeue,
515 .stream_enqueue = virtio_transport_stream_enqueue,
516 .stream_has_data = virtio_transport_stream_has_data,
517 .stream_has_space = virtio_transport_stream_has_space,
518 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat,
519 .stream_is_active = virtio_transport_stream_is_active,
520 .stream_allow = virtio_transport_stream_allow,
521
522 .seqpacket_dequeue = virtio_transport_seqpacket_dequeue,
523 .seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
524 .seqpacket_allow = virtio_transport_seqpacket_allow,
525 .seqpacket_has_data = virtio_transport_seqpacket_has_data,
526
527 .msgzerocopy_allow = virtio_transport_msgzerocopy_allow,
528
529 .notify_poll_in = virtio_transport_notify_poll_in,
530 .notify_poll_out = virtio_transport_notify_poll_out,
531 .notify_recv_init = virtio_transport_notify_recv_init,
532 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block,
533 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,
534 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
535 .notify_send_init = virtio_transport_notify_send_init,
536 .notify_send_pre_block = virtio_transport_notify_send_pre_block,
537 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,
538 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
539 .notify_buffer_size = virtio_transport_notify_buffer_size,
540 .notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat,
541
542 .read_skb = virtio_transport_read_skb,
543 },
544
545 .send_pkt = virtio_transport_send_pkt,
546 .can_msgzerocopy = virtio_transport_can_msgzerocopy,
547 };
548
virtio_transport_seqpacket_allow(u32 remote_cid)549 static bool virtio_transport_seqpacket_allow(u32 remote_cid)
550 {
551 struct virtio_vsock *vsock;
552 bool seqpacket_allow;
553
554 seqpacket_allow = false;
555 rcu_read_lock();
556 vsock = rcu_dereference(the_virtio_vsock);
557 if (vsock)
558 seqpacket_allow = vsock->seqpacket_allow;
559 rcu_read_unlock();
560
561 return seqpacket_allow;
562 }
563
virtio_transport_rx_work(struct work_struct * work)564 static void virtio_transport_rx_work(struct work_struct *work)
565 {
566 struct virtio_vsock *vsock =
567 container_of(work, struct virtio_vsock, rx_work);
568 struct virtqueue *vq;
569
570 vq = vsock->vqs[VSOCK_VQ_RX];
571
572 mutex_lock(&vsock->rx_lock);
573
574 if (!vsock->rx_run)
575 goto out;
576
577 do {
578 virtqueue_disable_cb(vq);
579 for (;;) {
580 struct sk_buff *skb;
581 unsigned int len;
582
583 if (!virtio_transport_more_replies(vsock)) {
584 /* Stop rx until the device processes already
585 * pending replies. Leave rx virtqueue
586 * callbacks disabled.
587 */
588 goto out;
589 }
590
591 skb = virtqueue_get_buf(vq, &len);
592 if (!skb)
593 break;
594
595 vsock->rx_buf_nr--;
596
597 /* Drop short/long packets */
598 if (unlikely(len < sizeof(struct virtio_vsock_hdr) ||
599 len > virtio_vsock_skb_len(skb))) {
600 kfree_skb(skb);
601 continue;
602 }
603
604 virtio_vsock_skb_rx_put(skb);
605 virtio_transport_deliver_tap_pkt(skb);
606 virtio_transport_recv_pkt(&virtio_transport, skb);
607 }
608 } while (!virtqueue_enable_cb(vq));
609
610 out:
611 if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
612 virtio_vsock_rx_fill(vsock);
613 mutex_unlock(&vsock->rx_lock);
614 }
615
virtio_vsock_vqs_init(struct virtio_vsock * vsock)616 static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
617 {
618 struct virtio_device *vdev = vsock->vdev;
619 static const char * const names[] = {
620 "rx",
621 "tx",
622 "event",
623 };
624 vq_callback_t *callbacks[] = {
625 virtio_vsock_rx_done,
626 virtio_vsock_tx_done,
627 virtio_vsock_event_done,
628 };
629 int ret;
630
631 ret = virtio_find_vqs(vdev, VSOCK_VQ_MAX, vsock->vqs, callbacks, names,
632 NULL);
633 if (ret < 0)
634 return ret;
635
636 virtio_vsock_update_guest_cid(vsock);
637
638 virtio_device_ready(vdev);
639
640 return 0;
641 }
642
virtio_vsock_vqs_start(struct virtio_vsock * vsock)643 static void virtio_vsock_vqs_start(struct virtio_vsock *vsock)
644 {
645 mutex_lock(&vsock->tx_lock);
646 vsock->tx_run = true;
647 mutex_unlock(&vsock->tx_lock);
648
649 mutex_lock(&vsock->rx_lock);
650 virtio_vsock_rx_fill(vsock);
651 vsock->rx_run = true;
652 mutex_unlock(&vsock->rx_lock);
653
654 mutex_lock(&vsock->event_lock);
655 virtio_vsock_event_fill(vsock);
656 vsock->event_run = true;
657 mutex_unlock(&vsock->event_lock);
658
659 /* virtio_transport_send_pkt() can queue packets once
660 * the_virtio_vsock is set, but they won't be processed until
661 * vsock->tx_run is set to true. We queue vsock->send_pkt_work
662 * when initialization finishes to send those packets queued
663 * earlier.
664 * We don't need to queue the other workers (rx, event) because
665 * as long as we don't fill the queues with empty buffers, the
666 * host can't send us any notification.
667 */
668 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
669 }
670
virtio_vsock_vqs_del(struct virtio_vsock * vsock)671 static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)
672 {
673 struct virtio_device *vdev = vsock->vdev;
674 struct sk_buff *skb;
675
676 /* Reset all connected sockets when the VQs disappear */
677 vsock_for_each_connected_socket(&virtio_transport.transport,
678 virtio_vsock_reset_sock);
679
680 /* Stop all work handlers to make sure no one is accessing the device,
681 * so we can safely call virtio_reset_device().
682 */
683 mutex_lock(&vsock->rx_lock);
684 vsock->rx_run = false;
685 mutex_unlock(&vsock->rx_lock);
686
687 mutex_lock(&vsock->tx_lock);
688 vsock->tx_run = false;
689 mutex_unlock(&vsock->tx_lock);
690
691 mutex_lock(&vsock->event_lock);
692 vsock->event_run = false;
693 mutex_unlock(&vsock->event_lock);
694
695 /* Flush all device writes and interrupts, device will not use any
696 * more buffers.
697 */
698 virtio_reset_device(vdev);
699
700 mutex_lock(&vsock->rx_lock);
701 while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
702 kfree_skb(skb);
703 mutex_unlock(&vsock->rx_lock);
704
705 mutex_lock(&vsock->tx_lock);
706 while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
707 kfree_skb(skb);
708 mutex_unlock(&vsock->tx_lock);
709
710 virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue);
711
712 /* Delete virtqueues and flush outstanding callbacks if any */
713 vdev->config->del_vqs(vdev);
714 }
715
virtio_vsock_probe(struct virtio_device * vdev)716 static int virtio_vsock_probe(struct virtio_device *vdev)
717 {
718 struct virtio_vsock *vsock = NULL;
719 int ret;
720 int i;
721
722 ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
723 if (ret)
724 return ret;
725
726 /* Only one virtio-vsock device per guest is supported */
727 if (rcu_dereference_protected(the_virtio_vsock,
728 lockdep_is_held(&the_virtio_vsock_mutex))) {
729 ret = -EBUSY;
730 goto out;
731 }
732
733 vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
734 if (!vsock) {
735 ret = -ENOMEM;
736 goto out;
737 }
738
739 vsock->vdev = vdev;
740
741 vsock->rx_buf_nr = 0;
742 vsock->rx_buf_max_nr = 0;
743 atomic_set(&vsock->queued_replies, 0);
744
745 mutex_init(&vsock->tx_lock);
746 mutex_init(&vsock->rx_lock);
747 mutex_init(&vsock->event_lock);
748 skb_queue_head_init(&vsock->send_pkt_queue);
749 INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
750 INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
751 INIT_WORK(&vsock->event_work, virtio_transport_event_work);
752 INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
753
754 if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
755 vsock->seqpacket_allow = true;
756
757 vdev->priv = vsock;
758
759 ret = virtio_vsock_vqs_init(vsock);
760 if (ret < 0)
761 goto out;
762
763 for (i = 0; i < ARRAY_SIZE(vsock->out_sgs); i++)
764 vsock->out_sgs[i] = &vsock->out_bufs[i];
765
766 rcu_assign_pointer(the_virtio_vsock, vsock);
767 virtio_vsock_vqs_start(vsock);
768
769 mutex_unlock(&the_virtio_vsock_mutex);
770
771 return 0;
772
773 out:
774 kfree(vsock);
775 mutex_unlock(&the_virtio_vsock_mutex);
776 return ret;
777 }
778
virtio_vsock_remove(struct virtio_device * vdev)779 static void virtio_vsock_remove(struct virtio_device *vdev)
780 {
781 struct virtio_vsock *vsock = vdev->priv;
782
783 mutex_lock(&the_virtio_vsock_mutex);
784
785 vdev->priv = NULL;
786 rcu_assign_pointer(the_virtio_vsock, NULL);
787 synchronize_rcu();
788
789 virtio_vsock_vqs_del(vsock);
790
791 /* Other works can be queued before 'config->del_vqs()', so we flush
792 * all works before to free the vsock object to avoid use after free.
793 */
794 flush_work(&vsock->rx_work);
795 flush_work(&vsock->tx_work);
796 flush_work(&vsock->event_work);
797 flush_work(&vsock->send_pkt_work);
798
799 mutex_unlock(&the_virtio_vsock_mutex);
800
801 kfree(vsock);
802 }
803
804 #ifdef CONFIG_PM_SLEEP
virtio_vsock_freeze(struct virtio_device * vdev)805 static int virtio_vsock_freeze(struct virtio_device *vdev)
806 {
807 struct virtio_vsock *vsock = vdev->priv;
808
809 mutex_lock(&the_virtio_vsock_mutex);
810
811 rcu_assign_pointer(the_virtio_vsock, NULL);
812 synchronize_rcu();
813
814 virtio_vsock_vqs_del(vsock);
815
816 mutex_unlock(&the_virtio_vsock_mutex);
817
818 return 0;
819 }
820
virtio_vsock_restore(struct virtio_device * vdev)821 static int virtio_vsock_restore(struct virtio_device *vdev)
822 {
823 struct virtio_vsock *vsock = vdev->priv;
824 int ret;
825
826 mutex_lock(&the_virtio_vsock_mutex);
827
828 /* Only one virtio-vsock device per guest is supported */
829 if (rcu_dereference_protected(the_virtio_vsock,
830 lockdep_is_held(&the_virtio_vsock_mutex))) {
831 ret = -EBUSY;
832 goto out;
833 }
834
835 ret = virtio_vsock_vqs_init(vsock);
836 if (ret < 0)
837 goto out;
838
839 rcu_assign_pointer(the_virtio_vsock, vsock);
840 virtio_vsock_vqs_start(vsock);
841
842 out:
843 mutex_unlock(&the_virtio_vsock_mutex);
844 return ret;
845 }
846 #endif /* CONFIG_PM_SLEEP */
847
848 static struct virtio_device_id id_table[] = {
849 { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
850 { 0 },
851 };
852
853 static unsigned int features[] = {
854 VIRTIO_VSOCK_F_SEQPACKET
855 };
856
857 static struct virtio_driver virtio_vsock_driver = {
858 .feature_table = features,
859 .feature_table_size = ARRAY_SIZE(features),
860 .driver.name = KBUILD_MODNAME,
861 .driver.owner = THIS_MODULE,
862 .id_table = id_table,
863 .probe = virtio_vsock_probe,
864 .remove = virtio_vsock_remove,
865 #ifdef CONFIG_PM_SLEEP
866 .freeze = virtio_vsock_freeze,
867 .restore = virtio_vsock_restore,
868 #endif
869 };
870
virtio_vsock_init(void)871 static int __init virtio_vsock_init(void)
872 {
873 int ret;
874
875 virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
876 if (!virtio_vsock_workqueue)
877 return -ENOMEM;
878
879 ret = vsock_core_register(&virtio_transport.transport,
880 VSOCK_TRANSPORT_F_G2H);
881 if (ret)
882 goto out_wq;
883
884 ret = register_virtio_driver(&virtio_vsock_driver);
885 if (ret)
886 goto out_vci;
887
888 return 0;
889
890 out_vci:
891 vsock_core_unregister(&virtio_transport.transport);
892 out_wq:
893 destroy_workqueue(virtio_vsock_workqueue);
894 return ret;
895 }
896
virtio_vsock_exit(void)897 static void __exit virtio_vsock_exit(void)
898 {
899 unregister_virtio_driver(&virtio_vsock_driver);
900 vsock_core_unregister(&virtio_transport.transport);
901 destroy_workqueue(virtio_vsock_workqueue);
902 }
903
904 module_init(virtio_vsock_init);
905 module_exit(virtio_vsock_exit);
906 MODULE_LICENSE("GPL v2");
907 MODULE_AUTHOR("Asias He");
908 MODULE_DESCRIPTION("virtio transport for vsock");
909 MODULE_DEVICE_TABLE(virtio, id_table);
910