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