blob: 936d7eee62d03efbac1e278272ca8fd917a40622 [file] [log] [blame]
Asias He0ea9e1d2016-07-28 15:36:33 +01001/*
2 * virtio transport for vsock
3 *
4 * Copyright (C) 2013-2015 Red Hat, Inc.
5 * Author: Asias He <asias@redhat.com>
6 * Stefan Hajnoczi <stefanha@redhat.com>
7 *
8 * Some of the code is take from Gerd Hoffmann <kraxel@redhat.com>'s
9 * early virtio-vsock proof-of-concept bits.
10 *
11 * This work is licensed under the terms of the GNU GPL, version 2.
12 */
13#include <linux/spinlock.h>
14#include <linux/module.h>
15#include <linux/list.h>
16#include <linux/atomic.h>
17#include <linux/virtio.h>
18#include <linux/virtio_ids.h>
19#include <linux/virtio_config.h>
20#include <linux/virtio_vsock.h>
21#include <net/sock.h>
22#include <linux/mutex.h>
23#include <net/af_vsock.h>
24
25static struct workqueue_struct *virtio_vsock_workqueue;
26static struct virtio_vsock *the_virtio_vsock;
27static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
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
43 struct work_struct send_pkt_work;
44 spinlock_t send_pkt_list_lock;
45 struct list_head send_pkt_list;
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 int rx_buf_nr;
54 int rx_buf_max_nr;
55
56 /* The following fields are protected by event_lock.
57 * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
58 */
59 struct mutex event_lock;
60 struct virtio_vsock_event event_list[8];
61
62 u32 guest_cid;
63};
64
65static struct virtio_vsock *virtio_vsock_get(void)
66{
67 return the_virtio_vsock;
68}
69
70static u32 virtio_transport_get_local_cid(void)
71{
72 struct virtio_vsock *vsock = virtio_vsock_get();
73
74 return vsock->guest_cid;
75}
76
77static void
78virtio_transport_send_pkt_work(struct work_struct *work)
79{
80 struct virtio_vsock *vsock =
81 container_of(work, struct virtio_vsock, send_pkt_work);
82 struct virtqueue *vq;
83 bool added = false;
84 bool restart_rx = false;
85
86 mutex_lock(&vsock->tx_lock);
87
88 vq = vsock->vqs[VSOCK_VQ_TX];
89
Asias He0ea9e1d2016-07-28 15:36:33 +010090 for (;;) {
91 struct virtio_vsock_pkt *pkt;
92 struct scatterlist hdr, buf, *sgs[2];
93 int ret, in_sg = 0, out_sg = 0;
94 bool reply;
95
96 spin_lock_bh(&vsock->send_pkt_list_lock);
97 if (list_empty(&vsock->send_pkt_list)) {
98 spin_unlock_bh(&vsock->send_pkt_list_lock);
Asias He0ea9e1d2016-07-28 15:36:33 +010099 break;
100 }
101
102 pkt = list_first_entry(&vsock->send_pkt_list,
103 struct virtio_vsock_pkt, list);
104 list_del_init(&pkt->list);
105 spin_unlock_bh(&vsock->send_pkt_list_lock);
106
107 reply = pkt->reply;
108
109 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
110 sgs[out_sg++] = &hdr;
111 if (pkt->buf) {
112 sg_init_one(&buf, pkt->buf, pkt->len);
113 sgs[out_sg++] = &buf;
114 }
115
116 ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
Gerard Garcia21bc54f2016-08-10 17:24:34 +0200117 /* Usually this means that there is no more space available in
118 * the vq
119 */
Asias He0ea9e1d2016-07-28 15:36:33 +0100120 if (ret < 0) {
121 spin_lock_bh(&vsock->send_pkt_list_lock);
122 list_add(&pkt->list, &vsock->send_pkt_list);
123 spin_unlock_bh(&vsock->send_pkt_list_lock);
Asias He0ea9e1d2016-07-28 15:36:33 +0100124 break;
125 }
126
127 if (reply) {
128 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
129 int val;
130
131 val = atomic_dec_return(&vsock->queued_replies);
132
133 /* Do we now have resources to resume rx processing? */
134 if (val + 1 == virtqueue_get_vring_size(rx_vq))
135 restart_rx = true;
136 }
137
138 added = true;
139 }
140
141 if (added)
142 virtqueue_kick(vq);
143
144 mutex_unlock(&vsock->tx_lock);
145
146 if (restart_rx)
147 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
148}
149
150static int
151virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
152{
153 struct virtio_vsock *vsock;
154 int len = pkt->len;
155
156 vsock = virtio_vsock_get();
157 if (!vsock) {
158 virtio_transport_free_pkt(pkt);
159 return -ENODEV;
160 }
161
162 if (pkt->reply)
163 atomic_inc(&vsock->queued_replies);
164
165 spin_lock_bh(&vsock->send_pkt_list_lock);
166 list_add_tail(&pkt->list, &vsock->send_pkt_list);
167 spin_unlock_bh(&vsock->send_pkt_list_lock);
168
169 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
170 return len;
171}
172
173static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
174{
175 int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
176 struct virtio_vsock_pkt *pkt;
177 struct scatterlist hdr, buf, *sgs[2];
178 struct virtqueue *vq;
179 int ret;
180
181 vq = vsock->vqs[VSOCK_VQ_RX];
182
183 do {
184 pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
185 if (!pkt)
186 break;
187
188 pkt->buf = kmalloc(buf_len, GFP_KERNEL);
189 if (!pkt->buf) {
190 virtio_transport_free_pkt(pkt);
191 break;
192 }
193
194 pkt->len = buf_len;
195
196 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
197 sgs[0] = &hdr;
198
199 sg_init_one(&buf, pkt->buf, buf_len);
200 sgs[1] = &buf;
201 ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
202 if (ret) {
203 virtio_transport_free_pkt(pkt);
204 break;
205 }
206 vsock->rx_buf_nr++;
207 } while (vq->num_free);
208 if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
209 vsock->rx_buf_max_nr = vsock->rx_buf_nr;
210 virtqueue_kick(vq);
211}
212
213static void virtio_transport_tx_work(struct work_struct *work)
214{
215 struct virtio_vsock *vsock =
216 container_of(work, struct virtio_vsock, tx_work);
217 struct virtqueue *vq;
218 bool added = false;
219
220 vq = vsock->vqs[VSOCK_VQ_TX];
221 mutex_lock(&vsock->tx_lock);
222 do {
223 struct virtio_vsock_pkt *pkt;
224 unsigned int len;
225
226 virtqueue_disable_cb(vq);
227 while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
228 virtio_transport_free_pkt(pkt);
229 added = true;
230 }
231 } while (!virtqueue_enable_cb(vq));
232 mutex_unlock(&vsock->tx_lock);
233
234 if (added)
235 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
236}
237
238/* Is there space left for replies to rx packets? */
239static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
240{
241 struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
242 int val;
243
244 smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
245 val = atomic_read(&vsock->queued_replies);
246
247 return val < virtqueue_get_vring_size(vq);
248}
249
250static void virtio_transport_rx_work(struct work_struct *work)
251{
252 struct virtio_vsock *vsock =
253 container_of(work, struct virtio_vsock, rx_work);
254 struct virtqueue *vq;
255
256 vq = vsock->vqs[VSOCK_VQ_RX];
257
258 mutex_lock(&vsock->rx_lock);
259
260 do {
261 virtqueue_disable_cb(vq);
262 for (;;) {
263 struct virtio_vsock_pkt *pkt;
264 unsigned int len;
265
266 if (!virtio_transport_more_replies(vsock)) {
267 /* Stop rx until the device processes already
268 * pending replies. Leave rx virtqueue
269 * callbacks disabled.
270 */
271 goto out;
272 }
273
274 pkt = virtqueue_get_buf(vq, &len);
275 if (!pkt) {
276 break;
277 }
278
279 vsock->rx_buf_nr--;
280
281 /* Drop short/long packets */
282 if (unlikely(len < sizeof(pkt->hdr) ||
283 len > sizeof(pkt->hdr) + pkt->len)) {
284 virtio_transport_free_pkt(pkt);
285 continue;
286 }
287
288 pkt->len = len - sizeof(pkt->hdr);
289 virtio_transport_recv_pkt(pkt);
290 }
291 } while (!virtqueue_enable_cb(vq));
292
293out:
294 if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
295 virtio_vsock_rx_fill(vsock);
296 mutex_unlock(&vsock->rx_lock);
297}
298
299/* event_lock must be held */
300static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
301 struct virtio_vsock_event *event)
302{
303 struct scatterlist sg;
304 struct virtqueue *vq;
305
306 vq = vsock->vqs[VSOCK_VQ_EVENT];
307
308 sg_init_one(&sg, event, sizeof(*event));
309
310 return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
311}
312
313/* event_lock must be held */
314static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
315{
316 size_t i;
317
318 for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
319 struct virtio_vsock_event *event = &vsock->event_list[i];
320
321 virtio_vsock_event_fill_one(vsock, event);
322 }
323
324 virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
325}
326
327static void virtio_vsock_reset_sock(struct sock *sk)
328{
329 lock_sock(sk);
330 sk->sk_state = SS_UNCONNECTED;
331 sk->sk_err = ECONNRESET;
332 sk->sk_error_report(sk);
333 release_sock(sk);
334}
335
336static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
337{
338 struct virtio_device *vdev = vsock->vdev;
339 u64 guest_cid;
340
341 vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
342 &guest_cid, sizeof(guest_cid));
343 vsock->guest_cid = le64_to_cpu(guest_cid);
344}
345
346/* event_lock must be held */
347static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
348 struct virtio_vsock_event *event)
349{
350 switch (le32_to_cpu(event->id)) {
351 case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
352 virtio_vsock_update_guest_cid(vsock);
353 vsock_for_each_connected_socket(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 do {
369 struct virtio_vsock_event *event;
370 unsigned int len;
371
372 virtqueue_disable_cb(vq);
373 while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
374 if (len == sizeof(*event))
375 virtio_vsock_event_handle(vsock, event);
376
377 virtio_vsock_event_fill_one(vsock, event);
378 }
379 } while (!virtqueue_enable_cb(vq));
380
381 virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
382
383 mutex_unlock(&vsock->event_lock);
384}
385
386static void virtio_vsock_event_done(struct virtqueue *vq)
387{
388 struct virtio_vsock *vsock = vq->vdev->priv;
389
390 if (!vsock)
391 return;
392 queue_work(virtio_vsock_workqueue, &vsock->event_work);
393}
394
395static void virtio_vsock_tx_done(struct virtqueue *vq)
396{
397 struct virtio_vsock *vsock = vq->vdev->priv;
398
399 if (!vsock)
400 return;
401 queue_work(virtio_vsock_workqueue, &vsock->tx_work);
402}
403
404static void virtio_vsock_rx_done(struct virtqueue *vq)
405{
406 struct virtio_vsock *vsock = vq->vdev->priv;
407
408 if (!vsock)
409 return;
410 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
411}
412
413static struct virtio_transport virtio_transport = {
414 .transport = {
415 .get_local_cid = virtio_transport_get_local_cid,
416
417 .init = virtio_transport_do_socket_init,
418 .destruct = virtio_transport_destruct,
419 .release = virtio_transport_release,
420 .connect = virtio_transport_connect,
421 .shutdown = virtio_transport_shutdown,
422
423 .dgram_bind = virtio_transport_dgram_bind,
424 .dgram_dequeue = virtio_transport_dgram_dequeue,
425 .dgram_enqueue = virtio_transport_dgram_enqueue,
426 .dgram_allow = virtio_transport_dgram_allow,
427
428 .stream_dequeue = virtio_transport_stream_dequeue,
429 .stream_enqueue = virtio_transport_stream_enqueue,
430 .stream_has_data = virtio_transport_stream_has_data,
431 .stream_has_space = virtio_transport_stream_has_space,
432 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat,
433 .stream_is_active = virtio_transport_stream_is_active,
434 .stream_allow = virtio_transport_stream_allow,
435
436 .notify_poll_in = virtio_transport_notify_poll_in,
437 .notify_poll_out = virtio_transport_notify_poll_out,
438 .notify_recv_init = virtio_transport_notify_recv_init,
439 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block,
440 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,
441 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
442 .notify_send_init = virtio_transport_notify_send_init,
443 .notify_send_pre_block = virtio_transport_notify_send_pre_block,
444 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,
445 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
446
447 .set_buffer_size = virtio_transport_set_buffer_size,
448 .set_min_buffer_size = virtio_transport_set_min_buffer_size,
449 .set_max_buffer_size = virtio_transport_set_max_buffer_size,
450 .get_buffer_size = virtio_transport_get_buffer_size,
451 .get_min_buffer_size = virtio_transport_get_min_buffer_size,
452 .get_max_buffer_size = virtio_transport_get_max_buffer_size,
453 },
454
455 .send_pkt = virtio_transport_send_pkt,
456};
457
458static int virtio_vsock_probe(struct virtio_device *vdev)
459{
460 vq_callback_t *callbacks[] = {
461 virtio_vsock_rx_done,
462 virtio_vsock_tx_done,
463 virtio_vsock_event_done,
464 };
465 static const char * const names[] = {
466 "rx",
467 "tx",
468 "event",
469 };
470 struct virtio_vsock *vsock = NULL;
471 int ret;
472
473 ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
474 if (ret)
475 return ret;
476
477 /* Only one virtio-vsock device per guest is supported */
478 if (the_virtio_vsock) {
479 ret = -EBUSY;
480 goto out;
481 }
482
483 vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
484 if (!vsock) {
485 ret = -ENOMEM;
486 goto out;
487 }
488
489 vsock->vdev = vdev;
490
491 ret = vsock->vdev->config->find_vqs(vsock->vdev, VSOCK_VQ_MAX,
492 vsock->vqs, callbacks, names);
493 if (ret < 0)
494 goto out;
495
496 virtio_vsock_update_guest_cid(vsock);
497
498 ret = vsock_core_init(&virtio_transport.transport);
499 if (ret < 0)
500 goto out_vqs;
501
502 vsock->rx_buf_nr = 0;
503 vsock->rx_buf_max_nr = 0;
504 atomic_set(&vsock->queued_replies, 0);
505
506 vdev->priv = vsock;
507 the_virtio_vsock = vsock;
508 mutex_init(&vsock->tx_lock);
509 mutex_init(&vsock->rx_lock);
510 mutex_init(&vsock->event_lock);
511 spin_lock_init(&vsock->send_pkt_list_lock);
512 INIT_LIST_HEAD(&vsock->send_pkt_list);
513 INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
514 INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
515 INIT_WORK(&vsock->event_work, virtio_transport_event_work);
516 INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
517
518 mutex_lock(&vsock->rx_lock);
519 virtio_vsock_rx_fill(vsock);
520 mutex_unlock(&vsock->rx_lock);
521
522 mutex_lock(&vsock->event_lock);
523 virtio_vsock_event_fill(vsock);
524 mutex_unlock(&vsock->event_lock);
525
526 mutex_unlock(&the_virtio_vsock_mutex);
527 return 0;
528
529out_vqs:
530 vsock->vdev->config->del_vqs(vsock->vdev);
531out:
532 kfree(vsock);
533 mutex_unlock(&the_virtio_vsock_mutex);
534 return ret;
535}
536
537static void virtio_vsock_remove(struct virtio_device *vdev)
538{
539 struct virtio_vsock *vsock = vdev->priv;
540 struct virtio_vsock_pkt *pkt;
541
542 flush_work(&vsock->rx_work);
543 flush_work(&vsock->tx_work);
544 flush_work(&vsock->event_work);
545 flush_work(&vsock->send_pkt_work);
546
547 vdev->config->reset(vdev);
548
549 mutex_lock(&vsock->rx_lock);
550 while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
551 virtio_transport_free_pkt(pkt);
552 mutex_unlock(&vsock->rx_lock);
553
554 mutex_lock(&vsock->tx_lock);
555 while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
556 virtio_transport_free_pkt(pkt);
557 mutex_unlock(&vsock->tx_lock);
558
559 spin_lock_bh(&vsock->send_pkt_list_lock);
560 while (!list_empty(&vsock->send_pkt_list)) {
561 pkt = list_first_entry(&vsock->send_pkt_list,
562 struct virtio_vsock_pkt, list);
563 list_del(&pkt->list);
564 virtio_transport_free_pkt(pkt);
565 }
566 spin_unlock_bh(&vsock->send_pkt_list_lock);
567
568 mutex_lock(&the_virtio_vsock_mutex);
569 the_virtio_vsock = NULL;
570 vsock_core_exit();
571 mutex_unlock(&the_virtio_vsock_mutex);
572
573 vdev->config->del_vqs(vdev);
574
575 kfree(vsock);
576}
577
578static struct virtio_device_id id_table[] = {
579 { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
580 { 0 },
581};
582
583static unsigned int features[] = {
584};
585
586static struct virtio_driver virtio_vsock_driver = {
587 .feature_table = features,
588 .feature_table_size = ARRAY_SIZE(features),
589 .driver.name = KBUILD_MODNAME,
590 .driver.owner = THIS_MODULE,
591 .id_table = id_table,
592 .probe = virtio_vsock_probe,
593 .remove = virtio_vsock_remove,
594};
595
596static int __init virtio_vsock_init(void)
597{
598 int ret;
599
600 virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
601 if (!virtio_vsock_workqueue)
602 return -ENOMEM;
603 ret = register_virtio_driver(&virtio_vsock_driver);
604 if (ret)
605 destroy_workqueue(virtio_vsock_workqueue);
606 return ret;
607}
608
609static void __exit virtio_vsock_exit(void)
610{
611 unregister_virtio_driver(&virtio_vsock_driver);
612 destroy_workqueue(virtio_vsock_workqueue);
613}
614
615module_init(virtio_vsock_init);
616module_exit(virtio_vsock_exit);
617MODULE_LICENSE("GPL v2");
618MODULE_AUTHOR("Asias He");
619MODULE_DESCRIPTION("virtio transport for vsock");
620MODULE_DEVICE_TABLE(virtio, id_table);