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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * vhost 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#include <linux/miscdevice.h>
10#include <linux/atomic.h>
11#include <linux/module.h>
12#include <linux/mutex.h>
13#include <linux/vmalloc.h>
14#include <net/sock.h>
15#include <linux/virtio_vsock.h>
16#include <linux/vhost.h>
17#include <linux/hashtable.h>
18
19#include <net/af_vsock.h>
20#include "vhost.h"
21
22#define VHOST_VSOCK_DEFAULT_HOST_CID 2
23/* Max number of bytes transferred before requeueing the job.
24 * Using this limit prevents one virtqueue from starving others. */
25#define VHOST_VSOCK_WEIGHT 0x80000
26/* Max number of packets transferred before requeueing the job.
27 * Using this limit prevents one virtqueue from starving others with
28 * small pkts.
29 */
30#define VHOST_VSOCK_PKT_WEIGHT 256
31
32enum {
33 VHOST_VSOCK_FEATURES = VHOST_FEATURES |
34 (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
35 (1ULL << VIRTIO_VSOCK_F_SEQPACKET)
36};
37
38enum {
39 VHOST_VSOCK_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
40};
41
42/* Used to track all the vhost_vsock instances on the system. */
43static DEFINE_MUTEX(vhost_vsock_mutex);
44static DEFINE_READ_MOSTLY_HASHTABLE(vhost_vsock_hash, 8);
45
46struct vhost_vsock {
47 struct vhost_dev dev;
48 struct vhost_virtqueue vqs[2];
49
50 /* Link to global vhost_vsock_hash, writes use vhost_vsock_mutex */
51 struct hlist_node hash;
52
53 struct vhost_work send_pkt_work;
54 spinlock_t send_pkt_list_lock;
55 struct list_head send_pkt_list; /* host->guest pending packets */
56
57 atomic_t queued_replies;
58
59 u32 guest_cid;
60 bool seqpacket_allow;
61};
62
63static u32 vhost_transport_get_local_cid(void)
64{
65 return VHOST_VSOCK_DEFAULT_HOST_CID;
66}
67
68/* Callers that dereference the return value must hold vhost_vsock_mutex or the
69 * RCU read lock.
70 */
71static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
72{
73 struct vhost_vsock *vsock;
74
75 hash_for_each_possible_rcu(vhost_vsock_hash, vsock, hash, guest_cid) {
76 u32 other_cid = vsock->guest_cid;
77
78 /* Skip instances that have no CID yet */
79 if (other_cid == 0)
80 continue;
81
82 if (other_cid == guest_cid)
83 return vsock;
84
85 }
86
87 return NULL;
88}
89
90static void
91vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
92 struct vhost_virtqueue *vq)
93{
94 struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
95 int pkts = 0, total_len = 0;
96 bool added = false;
97 bool restart_tx = false;
98
99 mutex_lock(&vq->mutex);
100
101 if (!vhost_vq_get_backend(vq))
102 goto out;
103
104 if (!vq_meta_prefetch(vq))
105 goto out;
106
107 /* Avoid further vmexits, we're already processing the virtqueue */
108 vhost_disable_notify(&vsock->dev, vq);
109
110 do {
111 struct virtio_vsock_pkt *pkt;
112 struct iov_iter iov_iter;
113 unsigned out, in;
114 size_t nbytes;
115 size_t iov_len, payload_len;
116 int head;
117 u32 flags_to_restore = 0;
118
119 spin_lock_bh(&vsock->send_pkt_list_lock);
120 if (list_empty(&vsock->send_pkt_list)) {
121 spin_unlock_bh(&vsock->send_pkt_list_lock);
122 vhost_enable_notify(&vsock->dev, vq);
123 break;
124 }
125
126 pkt = list_first_entry(&vsock->send_pkt_list,
127 struct virtio_vsock_pkt, list);
128 list_del_init(&pkt->list);
129 spin_unlock_bh(&vsock->send_pkt_list_lock);
130
131 head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
132 &out, &in, NULL, NULL);
133 if (head < 0) {
134 spin_lock_bh(&vsock->send_pkt_list_lock);
135 list_add(&pkt->list, &vsock->send_pkt_list);
136 spin_unlock_bh(&vsock->send_pkt_list_lock);
137 break;
138 }
139
140 if (head == vq->num) {
141 spin_lock_bh(&vsock->send_pkt_list_lock);
142 list_add(&pkt->list, &vsock->send_pkt_list);
143 spin_unlock_bh(&vsock->send_pkt_list_lock);
144
145 /* We cannot finish yet if more buffers snuck in while
146 * re-enabling notify.
147 */
148 if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
149 vhost_disable_notify(&vsock->dev, vq);
150 continue;
151 }
152 break;
153 }
154
155 if (out) {
156 virtio_transport_free_pkt(pkt);
157 vq_err(vq, "Expected 0 output buffers, got %u\n", out);
158 break;
159 }
160
161 iov_len = iov_length(&vq->iov[out], in);
162 if (iov_len < sizeof(pkt->hdr)) {
163 virtio_transport_free_pkt(pkt);
164 vq_err(vq, "Buffer len [%zu] too small\n", iov_len);
165 break;
166 }
167
168 iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[out], in, iov_len);
169 payload_len = pkt->len - pkt->off;
170
171 /* If the packet is greater than the space available in the
172 * buffer, we split it using multiple buffers.
173 */
174 if (payload_len > iov_len - sizeof(pkt->hdr)) {
175 payload_len = iov_len - sizeof(pkt->hdr);
176
177 /* As we are copying pieces of large packet's buffer to
178 * small rx buffers, headers of packets in rx queue are
179 * created dynamically and are initialized with header
180 * of current packet(except length). But in case of
181 * SOCK_SEQPACKET, we also must clear message delimeter
182 * bit (VIRTIO_VSOCK_SEQ_EOM) and MSG_EOR bit
183 * (VIRTIO_VSOCK_SEQ_EOR) if set. Otherwise,
184 * there will be sequence of packets with these
185 * bits set. After initialized header will be copied to
186 * rx buffer, these required bits will be restored.
187 */
188 if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM) {
189 pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
190 flags_to_restore |= VIRTIO_VSOCK_SEQ_EOM;
191
192 if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR) {
193 pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
194 flags_to_restore |= VIRTIO_VSOCK_SEQ_EOR;
195 }
196 }
197 }
198
199 /* Set the correct length in the header */
200 pkt->hdr.len = cpu_to_le32(payload_len);
201
202 nbytes = copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
203 if (nbytes != sizeof(pkt->hdr)) {
204 virtio_transport_free_pkt(pkt);
205 vq_err(vq, "Faulted on copying pkt hdr\n");
206 break;
207 }
208
209 nbytes = copy_to_iter(pkt->buf + pkt->off, payload_len,
210 &iov_iter);
211 if (nbytes != payload_len) {
212 virtio_transport_free_pkt(pkt);
213 vq_err(vq, "Faulted on copying pkt buf\n");
214 break;
215 }
216
217 /* Deliver to monitoring devices all packets that we
218 * will transmit.
219 */
220 virtio_transport_deliver_tap_pkt(pkt);
221
222 vhost_add_used(vq, head, sizeof(pkt->hdr) + payload_len);
223 added = true;
224
225 pkt->off += payload_len;
226 total_len += payload_len;
227
228 /* If we didn't send all the payload we can requeue the packet
229 * to send it with the next available buffer.
230 */
231 if (pkt->off < pkt->len) {
232 pkt->hdr.flags |= cpu_to_le32(flags_to_restore);
233
234 /* We are queueing the same virtio_vsock_pkt to handle
235 * the remaining bytes, and we want to deliver it
236 * to monitoring devices in the next iteration.
237 */
238 pkt->tap_delivered = false;
239
240 spin_lock_bh(&vsock->send_pkt_list_lock);
241 list_add(&pkt->list, &vsock->send_pkt_list);
242 spin_unlock_bh(&vsock->send_pkt_list_lock);
243 } else {
244 if (pkt->reply) {
245 int val;
246
247 val = atomic_dec_return(&vsock->queued_replies);
248
249 /* Do we have resources to resume tx
250 * processing?
251 */
252 if (val + 1 == tx_vq->num)
253 restart_tx = true;
254 }
255
256 virtio_transport_free_pkt(pkt);
257 }
258 } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
259 if (added)
260 vhost_signal(&vsock->dev, vq);
261
262out:
263 mutex_unlock(&vq->mutex);
264
265 if (restart_tx)
266 vhost_poll_queue(&tx_vq->poll);
267}
268
269static void vhost_transport_send_pkt_work(struct vhost_work *work)
270{
271 struct vhost_virtqueue *vq;
272 struct vhost_vsock *vsock;
273
274 vsock = container_of(work, struct vhost_vsock, send_pkt_work);
275 vq = &vsock->vqs[VSOCK_VQ_RX];
276
277 vhost_transport_do_send_pkt(vsock, vq);
278}
279
280static int
281vhost_transport_send_pkt(struct virtio_vsock_pkt *pkt)
282{
283 struct vhost_vsock *vsock;
284 int len = pkt->len;
285
286 rcu_read_lock();
287
288 /* Find the vhost_vsock according to guest context id */
289 vsock = vhost_vsock_get(le64_to_cpu(pkt->hdr.dst_cid));
290 if (!vsock) {
291 rcu_read_unlock();
292 virtio_transport_free_pkt(pkt);
293 return -ENODEV;
294 }
295
296 if (pkt->reply)
297 atomic_inc(&vsock->queued_replies);
298
299 spin_lock_bh(&vsock->send_pkt_list_lock);
300 list_add_tail(&pkt->list, &vsock->send_pkt_list);
301 spin_unlock_bh(&vsock->send_pkt_list_lock);
302
303 vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
304
305 rcu_read_unlock();
306 return len;
307}
308
309static int
310vhost_transport_cancel_pkt(struct vsock_sock *vsk)
311{
312 struct vhost_vsock *vsock;
313 struct virtio_vsock_pkt *pkt, *n;
314 int cnt = 0;
315 int ret = -ENODEV;
316 LIST_HEAD(freeme);
317
318 rcu_read_lock();
319
320 /* Find the vhost_vsock according to guest context id */
321 vsock = vhost_vsock_get(vsk->remote_addr.svm_cid);
322 if (!vsock)
323 goto out;
324
325 spin_lock_bh(&vsock->send_pkt_list_lock);
326 list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
327 if (pkt->vsk != vsk)
328 continue;
329 list_move(&pkt->list, &freeme);
330 }
331 spin_unlock_bh(&vsock->send_pkt_list_lock);
332
333 list_for_each_entry_safe(pkt, n, &freeme, list) {
334 if (pkt->reply)
335 cnt++;
336 list_del(&pkt->list);
337 virtio_transport_free_pkt(pkt);
338 }
339
340 if (cnt) {
341 struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
342 int new_cnt;
343
344 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
345 if (new_cnt + cnt >= tx_vq->num && new_cnt < tx_vq->num)
346 vhost_poll_queue(&tx_vq->poll);
347 }
348
349 ret = 0;
350out:
351 rcu_read_unlock();
352 return ret;
353}
354
355static struct virtio_vsock_pkt *
356vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
357 unsigned int out, unsigned int in)
358{
359 struct virtio_vsock_pkt *pkt;
360 struct iov_iter iov_iter;
361 size_t nbytes;
362 size_t len;
363
364 if (in != 0) {
365 vq_err(vq, "Expected 0 input buffers, got %u\n", in);
366 return NULL;
367 }
368
369 pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
370 if (!pkt)
371 return NULL;
372
373 len = iov_length(vq->iov, out);
374 iov_iter_init(&iov_iter, ITER_SOURCE, vq->iov, out, len);
375
376 nbytes = copy_from_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
377 if (nbytes != sizeof(pkt->hdr)) {
378 vq_err(vq, "Expected %zu bytes for pkt->hdr, got %zu bytes\n",
379 sizeof(pkt->hdr), nbytes);
380 kfree(pkt);
381 return NULL;
382 }
383
384 pkt->len = le32_to_cpu(pkt->hdr.len);
385
386 /* No payload */
387 if (!pkt->len)
388 return pkt;
389
390 /* The pkt is too big */
391 if (pkt->len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
392 kfree(pkt);
393 return NULL;
394 }
395
396 pkt->buf = kvmalloc(pkt->len, GFP_KERNEL);
397 if (!pkt->buf) {
398 kfree(pkt);
399 return NULL;
400 }
401
402 pkt->buf_len = pkt->len;
403
404 nbytes = copy_from_iter(pkt->buf, pkt->len, &iov_iter);
405 if (nbytes != pkt->len) {
406 vq_err(vq, "Expected %u byte payload, got %zu bytes\n",
407 pkt->len, nbytes);
408 virtio_transport_free_pkt(pkt);
409 return NULL;
410 }
411
412 return pkt;
413}
414
415/* Is there space left for replies to rx packets? */
416static bool vhost_vsock_more_replies(struct vhost_vsock *vsock)
417{
418 struct vhost_virtqueue *vq = &vsock->vqs[VSOCK_VQ_TX];
419 int val;
420
421 smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
422 val = atomic_read(&vsock->queued_replies);
423
424 return val < vq->num;
425}
426
427static bool vhost_transport_seqpacket_allow(u32 remote_cid);
428
429static struct virtio_transport vhost_transport = {
430 .transport = {
431 .module = THIS_MODULE,
432
433 .get_local_cid = vhost_transport_get_local_cid,
434
435 .init = virtio_transport_do_socket_init,
436 .destruct = virtio_transport_destruct,
437 .release = virtio_transport_release,
438 .connect = virtio_transport_connect,
439 .shutdown = virtio_transport_shutdown,
440 .cancel_pkt = vhost_transport_cancel_pkt,
441
442 .dgram_enqueue = virtio_transport_dgram_enqueue,
443 .dgram_dequeue = virtio_transport_dgram_dequeue,
444 .dgram_bind = virtio_transport_dgram_bind,
445 .dgram_allow = virtio_transport_dgram_allow,
446
447 .stream_enqueue = virtio_transport_stream_enqueue,
448 .stream_dequeue = virtio_transport_stream_dequeue,
449 .stream_has_data = virtio_transport_stream_has_data,
450 .stream_has_space = virtio_transport_stream_has_space,
451 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat,
452 .stream_is_active = virtio_transport_stream_is_active,
453 .stream_allow = virtio_transport_stream_allow,
454
455 .seqpacket_dequeue = virtio_transport_seqpacket_dequeue,
456 .seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
457 .seqpacket_allow = vhost_transport_seqpacket_allow,
458 .seqpacket_has_data = virtio_transport_seqpacket_has_data,
459
460 .notify_poll_in = virtio_transport_notify_poll_in,
461 .notify_poll_out = virtio_transport_notify_poll_out,
462 .notify_recv_init = virtio_transport_notify_recv_init,
463 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block,
464 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,
465 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
466 .notify_send_init = virtio_transport_notify_send_init,
467 .notify_send_pre_block = virtio_transport_notify_send_pre_block,
468 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,
469 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
470 .notify_buffer_size = virtio_transport_notify_buffer_size,
471
472 },
473
474 .send_pkt = vhost_transport_send_pkt,
475};
476
477static bool vhost_transport_seqpacket_allow(u32 remote_cid)
478{
479 struct vhost_vsock *vsock;
480 bool seqpacket_allow = false;
481
482 rcu_read_lock();
483 vsock = vhost_vsock_get(remote_cid);
484
485 if (vsock)
486 seqpacket_allow = vsock->seqpacket_allow;
487
488 rcu_read_unlock();
489
490 return seqpacket_allow;
491}
492
493static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
494{
495 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
496 poll.work);
497 struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
498 dev);
499 struct virtio_vsock_pkt *pkt;
500 int head, pkts = 0, total_len = 0;
501 unsigned int out, in;
502 bool added = false;
503
504 mutex_lock(&vq->mutex);
505
506 if (!vhost_vq_get_backend(vq))
507 goto out;
508
509 if (!vq_meta_prefetch(vq))
510 goto out;
511
512 vhost_disable_notify(&vsock->dev, vq);
513 do {
514 if (!vhost_vsock_more_replies(vsock)) {
515 /* Stop tx until the device processes already
516 * pending replies. Leave tx virtqueue
517 * callbacks disabled.
518 */
519 goto no_more_replies;
520 }
521
522 head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
523 &out, &in, NULL, NULL);
524 if (head < 0)
525 break;
526
527 if (head == vq->num) {
528 if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
529 vhost_disable_notify(&vsock->dev, vq);
530 continue;
531 }
532 break;
533 }
534
535 pkt = vhost_vsock_alloc_pkt(vq, out, in);
536 if (!pkt) {
537 vq_err(vq, "Faulted on pkt\n");
538 continue;
539 }
540
541 total_len += sizeof(pkt->hdr) + pkt->len;
542
543 /* Deliver to monitoring devices all received packets */
544 virtio_transport_deliver_tap_pkt(pkt);
545
546 /* Only accept correctly addressed packets */
547 if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid &&
548 le64_to_cpu(pkt->hdr.dst_cid) ==
549 vhost_transport_get_local_cid())
550 virtio_transport_recv_pkt(&vhost_transport, pkt);
551 else
552 virtio_transport_free_pkt(pkt);
553
554 vhost_add_used(vq, head, 0);
555 added = true;
556 } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
557
558no_more_replies:
559 if (added)
560 vhost_signal(&vsock->dev, vq);
561
562out:
563 mutex_unlock(&vq->mutex);
564}
565
566static void vhost_vsock_handle_rx_kick(struct vhost_work *work)
567{
568 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
569 poll.work);
570 struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
571 dev);
572
573 vhost_transport_do_send_pkt(vsock, vq);
574}
575
576static int vhost_vsock_start(struct vhost_vsock *vsock)
577{
578 struct vhost_virtqueue *vq;
579 size_t i;
580 int ret;
581
582 mutex_lock(&vsock->dev.mutex);
583
584 ret = vhost_dev_check_owner(&vsock->dev);
585 if (ret)
586 goto err;
587
588 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
589 vq = &vsock->vqs[i];
590
591 mutex_lock(&vq->mutex);
592
593 if (!vhost_vq_access_ok(vq)) {
594 ret = -EFAULT;
595 goto err_vq;
596 }
597
598 if (!vhost_vq_get_backend(vq)) {
599 vhost_vq_set_backend(vq, vsock);
600 ret = vhost_vq_init_access(vq);
601 if (ret)
602 goto err_vq;
603 }
604
605 mutex_unlock(&vq->mutex);
606 }
607
608 /* Some packets may have been queued before the device was started,
609 * let's kick the send worker to send them.
610 */
611 vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
612
613 mutex_unlock(&vsock->dev.mutex);
614 return 0;
615
616err_vq:
617 vhost_vq_set_backend(vq, NULL);
618 mutex_unlock(&vq->mutex);
619
620 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
621 vq = &vsock->vqs[i];
622
623 mutex_lock(&vq->mutex);
624 vhost_vq_set_backend(vq, NULL);
625 mutex_unlock(&vq->mutex);
626 }
627err:
628 mutex_unlock(&vsock->dev.mutex);
629 return ret;
630}
631
632static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner)
633{
634 size_t i;
635 int ret = 0;
636
637 mutex_lock(&vsock->dev.mutex);
638
639 if (check_owner) {
640 ret = vhost_dev_check_owner(&vsock->dev);
641 if (ret)
642 goto err;
643 }
644
645 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
646 struct vhost_virtqueue *vq = &vsock->vqs[i];
647
648 mutex_lock(&vq->mutex);
649 vhost_vq_set_backend(vq, NULL);
650 mutex_unlock(&vq->mutex);
651 }
652
653err:
654 mutex_unlock(&vsock->dev.mutex);
655 return ret;
656}
657
658static void vhost_vsock_free(struct vhost_vsock *vsock)
659{
660 kvfree(vsock);
661}
662
663static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
664{
665 struct vhost_virtqueue **vqs;
666 struct vhost_vsock *vsock;
667 int ret;
668
669 /* This struct is large and allocation could fail, fall back to vmalloc
670 * if there is no other way.
671 */
672 vsock = kvmalloc(sizeof(*vsock), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
673 if (!vsock)
674 return -ENOMEM;
675
676 vqs = kmalloc_array(ARRAY_SIZE(vsock->vqs), sizeof(*vqs), GFP_KERNEL);
677 if (!vqs) {
678 ret = -ENOMEM;
679 goto out;
680 }
681
682 vsock->guest_cid = 0; /* no CID assigned yet */
683
684 atomic_set(&vsock->queued_replies, 0);
685
686 vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX];
687 vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX];
688 vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
689 vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
690
691 vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs),
692 UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT,
693 VHOST_VSOCK_WEIGHT, true, NULL);
694
695 file->private_data = vsock;
696 spin_lock_init(&vsock->send_pkt_list_lock);
697 INIT_LIST_HEAD(&vsock->send_pkt_list);
698 vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work);
699 return 0;
700
701out:
702 vhost_vsock_free(vsock);
703 return ret;
704}
705
706static void vhost_vsock_flush(struct vhost_vsock *vsock)
707{
708 vhost_dev_flush(&vsock->dev);
709}
710
711static void vhost_vsock_reset_orphans(struct sock *sk)
712{
713 struct vsock_sock *vsk = vsock_sk(sk);
714
715 /* vmci_transport.c doesn't take sk_lock here either. At least we're
716 * under vsock_table_lock so the sock cannot disappear while we're
717 * executing.
718 */
719
720 /* If the peer is still valid, no need to reset connection */
721 if (vhost_vsock_get(vsk->remote_addr.svm_cid))
722 return;
723
724 /* If the close timeout is pending, let it expire. This avoids races
725 * with the timeout callback.
726 */
727 if (vsk->close_work_scheduled)
728 return;
729
730 sock_set_flag(sk, SOCK_DONE);
731 vsk->peer_shutdown = SHUTDOWN_MASK;
732 sk->sk_state = SS_UNCONNECTED;
733 sk->sk_err = ECONNRESET;
734 sk_error_report(sk);
735}
736
737static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
738{
739 struct vhost_vsock *vsock = file->private_data;
740
741 mutex_lock(&vhost_vsock_mutex);
742 if (vsock->guest_cid)
743 hash_del_rcu(&vsock->hash);
744 mutex_unlock(&vhost_vsock_mutex);
745
746 /* Wait for other CPUs to finish using vsock */
747 synchronize_rcu();
748
749 /* Iterating over all connections for all CIDs to find orphans is
750 * inefficient. Room for improvement here. */
751 vsock_for_each_connected_socket(&vhost_transport.transport,
752 vhost_vsock_reset_orphans);
753
754 /* Don't check the owner, because we are in the release path, so we
755 * need to stop the vsock device in any case.
756 * vhost_vsock_stop() can not fail in this case, so we don't need to
757 * check the return code.
758 */
759 vhost_vsock_stop(vsock, false);
760 vhost_vsock_flush(vsock);
761 vhost_dev_stop(&vsock->dev);
762
763 spin_lock_bh(&vsock->send_pkt_list_lock);
764 while (!list_empty(&vsock->send_pkt_list)) {
765 struct virtio_vsock_pkt *pkt;
766
767 pkt = list_first_entry(&vsock->send_pkt_list,
768 struct virtio_vsock_pkt, list);
769 list_del_init(&pkt->list);
770 virtio_transport_free_pkt(pkt);
771 }
772 spin_unlock_bh(&vsock->send_pkt_list_lock);
773
774 vhost_dev_cleanup(&vsock->dev);
775 kfree(vsock->dev.vqs);
776 vhost_vsock_free(vsock);
777 return 0;
778}
779
780static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid)
781{
782 struct vhost_vsock *other;
783
784 /* Refuse reserved CIDs */
785 if (guest_cid <= VMADDR_CID_HOST ||
786 guest_cid == U32_MAX)
787 return -EINVAL;
788
789 /* 64-bit CIDs are not yet supported */
790 if (guest_cid > U32_MAX)
791 return -EINVAL;
792
793 /* Refuse if CID is assigned to the guest->host transport (i.e. nested
794 * VM), to make the loopback work.
795 */
796 if (vsock_find_cid(guest_cid))
797 return -EADDRINUSE;
798
799 /* Refuse if CID is already in use */
800 mutex_lock(&vhost_vsock_mutex);
801 other = vhost_vsock_get(guest_cid);
802 if (other && other != vsock) {
803 mutex_unlock(&vhost_vsock_mutex);
804 return -EADDRINUSE;
805 }
806
807 if (vsock->guest_cid)
808 hash_del_rcu(&vsock->hash);
809
810 vsock->guest_cid = guest_cid;
811 hash_add_rcu(vhost_vsock_hash, &vsock->hash, vsock->guest_cid);
812 mutex_unlock(&vhost_vsock_mutex);
813
814 return 0;
815}
816
817static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)
818{
819 struct vhost_virtqueue *vq;
820 int i;
821
822 if (features & ~VHOST_VSOCK_FEATURES)
823 return -EOPNOTSUPP;
824
825 mutex_lock(&vsock->dev.mutex);
826 if ((features & (1 << VHOST_F_LOG_ALL)) &&
827 !vhost_log_access_ok(&vsock->dev)) {
828 goto err;
829 }
830
831 if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) {
832 if (vhost_init_device_iotlb(&vsock->dev, true))
833 goto err;
834 }
835
836 if (features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET))
837 vsock->seqpacket_allow = true;
838
839 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
840 vq = &vsock->vqs[i];
841 mutex_lock(&vq->mutex);
842 vq->acked_features = features;
843 mutex_unlock(&vq->mutex);
844 }
845 mutex_unlock(&vsock->dev.mutex);
846 return 0;
847
848err:
849 mutex_unlock(&vsock->dev.mutex);
850 return -EFAULT;
851}
852
853static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl,
854 unsigned long arg)
855{
856 struct vhost_vsock *vsock = f->private_data;
857 void __user *argp = (void __user *)arg;
858 u64 guest_cid;
859 u64 features;
860 int start;
861 int r;
862
863 switch (ioctl) {
864 case VHOST_VSOCK_SET_GUEST_CID:
865 if (copy_from_user(&guest_cid, argp, sizeof(guest_cid)))
866 return -EFAULT;
867 return vhost_vsock_set_cid(vsock, guest_cid);
868 case VHOST_VSOCK_SET_RUNNING:
869 if (copy_from_user(&start, argp, sizeof(start)))
870 return -EFAULT;
871 if (start)
872 return vhost_vsock_start(vsock);
873 else
874 return vhost_vsock_stop(vsock, true);
875 case VHOST_GET_FEATURES:
876 features = VHOST_VSOCK_FEATURES;
877 if (copy_to_user(argp, &features, sizeof(features)))
878 return -EFAULT;
879 return 0;
880 case VHOST_SET_FEATURES:
881 if (copy_from_user(&features, argp, sizeof(features)))
882 return -EFAULT;
883 return vhost_vsock_set_features(vsock, features);
884 case VHOST_GET_BACKEND_FEATURES:
885 features = VHOST_VSOCK_BACKEND_FEATURES;
886 if (copy_to_user(argp, &features, sizeof(features)))
887 return -EFAULT;
888 return 0;
889 case VHOST_SET_BACKEND_FEATURES:
890 if (copy_from_user(&features, argp, sizeof(features)))
891 return -EFAULT;
892 if (features & ~VHOST_VSOCK_BACKEND_FEATURES)
893 return -EOPNOTSUPP;
894 vhost_set_backend_features(&vsock->dev, features);
895 return 0;
896 default:
897 mutex_lock(&vsock->dev.mutex);
898 r = vhost_dev_ioctl(&vsock->dev, ioctl, argp);
899 if (r == -ENOIOCTLCMD)
900 r = vhost_vring_ioctl(&vsock->dev, ioctl, argp);
901 else
902 vhost_vsock_flush(vsock);
903 mutex_unlock(&vsock->dev.mutex);
904 return r;
905 }
906}
907
908static ssize_t vhost_vsock_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
909{
910 struct file *file = iocb->ki_filp;
911 struct vhost_vsock *vsock = file->private_data;
912 struct vhost_dev *dev = &vsock->dev;
913 int noblock = file->f_flags & O_NONBLOCK;
914
915 return vhost_chr_read_iter(dev, to, noblock);
916}
917
918static ssize_t vhost_vsock_chr_write_iter(struct kiocb *iocb,
919 struct iov_iter *from)
920{
921 struct file *file = iocb->ki_filp;
922 struct vhost_vsock *vsock = file->private_data;
923 struct vhost_dev *dev = &vsock->dev;
924
925 return vhost_chr_write_iter(dev, from);
926}
927
928static __poll_t vhost_vsock_chr_poll(struct file *file, poll_table *wait)
929{
930 struct vhost_vsock *vsock = file->private_data;
931 struct vhost_dev *dev = &vsock->dev;
932
933 return vhost_chr_poll(file, dev, wait);
934}
935
936static const struct file_operations vhost_vsock_fops = {
937 .owner = THIS_MODULE,
938 .open = vhost_vsock_dev_open,
939 .release = vhost_vsock_dev_release,
940 .llseek = noop_llseek,
941 .unlocked_ioctl = vhost_vsock_dev_ioctl,
942 .compat_ioctl = compat_ptr_ioctl,
943 .read_iter = vhost_vsock_chr_read_iter,
944 .write_iter = vhost_vsock_chr_write_iter,
945 .poll = vhost_vsock_chr_poll,
946};
947
948static struct miscdevice vhost_vsock_misc = {
949 .minor = VHOST_VSOCK_MINOR,
950 .name = "vhost-vsock",
951 .fops = &vhost_vsock_fops,
952};
953
954static int __init vhost_vsock_init(void)
955{
956 int ret;
957
958 ret = vsock_core_register(&vhost_transport.transport,
959 VSOCK_TRANSPORT_F_H2G);
960 if (ret < 0)
961 return ret;
962
963 ret = misc_register(&vhost_vsock_misc);
964 if (ret) {
965 vsock_core_unregister(&vhost_transport.transport);
966 return ret;
967 }
968
969 return 0;
970};
971
972static void __exit vhost_vsock_exit(void)
973{
974 misc_deregister(&vhost_vsock_misc);
975 vsock_core_unregister(&vhost_transport.transport);
976};
977
978module_init(vhost_vsock_init);
979module_exit(vhost_vsock_exit);
980MODULE_LICENSE("GPL v2");
981MODULE_AUTHOR("Asias He");
982MODULE_DESCRIPTION("vhost transport for vsock ");
983MODULE_ALIAS_MISCDEV(VHOST_VSOCK_MINOR);
984MODULE_ALIAS("devname:vhost-vsock");