xref: /openbmc/linux/drivers/vhost/vsock.c (revision 9134211f)
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 
32 enum {
33 	VHOST_VSOCK_FEATURES = VHOST_FEATURES |
34 			       (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
35 			       (1ULL << VIRTIO_VSOCK_F_SEQPACKET)
36 };
37 
38 enum {
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. */
43 static DEFINE_MUTEX(vhost_vsock_mutex);
44 static DEFINE_READ_MOSTLY_HASHTABLE(vhost_vsock_hash, 8);
45 
46 struct 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 
62 static 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  */
70 static 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 
89 static void
90 vhost_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 		int head;
118 
119 		skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue);
120 
121 		if (!skb) {
122 			vhost_enable_notify(&vsock->dev, vq);
123 			break;
124 		}
125 
126 		head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
127 					 &out, &in, NULL, NULL);
128 		if (head < 0) {
129 			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
130 			break;
131 		}
132 
133 		if (head == vq->num) {
134 			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
135 			/* We cannot finish yet if more buffers snuck in while
136 			 * re-enabling notify.
137 			 */
138 			if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
139 				vhost_disable_notify(&vsock->dev, vq);
140 				continue;
141 			}
142 			break;
143 		}
144 
145 		if (out) {
146 			kfree_skb(skb);
147 			vq_err(vq, "Expected 0 output buffers, got %u\n", out);
148 			break;
149 		}
150 
151 		iov_len = iov_length(&vq->iov[out], in);
152 		if (iov_len < sizeof(*hdr)) {
153 			kfree_skb(skb);
154 			vq_err(vq, "Buffer len [%zu] too small\n", iov_len);
155 			break;
156 		}
157 
158 		iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[out], in, iov_len);
159 		payload_len = skb->len;
160 		hdr = virtio_vsock_hdr(skb);
161 
162 		/* If the packet is greater than the space available in the
163 		 * buffer, we split it using multiple buffers.
164 		 */
165 		if (payload_len > iov_len - sizeof(*hdr)) {
166 			payload_len = iov_len - sizeof(*hdr);
167 
168 			/* As we are copying pieces of large packet's buffer to
169 			 * small rx buffers, headers of packets in rx queue are
170 			 * created dynamically and are initialized with header
171 			 * of current packet(except length). But in case of
172 			 * SOCK_SEQPACKET, we also must clear message delimeter
173 			 * bit (VIRTIO_VSOCK_SEQ_EOM) and MSG_EOR bit
174 			 * (VIRTIO_VSOCK_SEQ_EOR) if set. Otherwise,
175 			 * there will be sequence of packets with these
176 			 * bits set. After initialized header will be copied to
177 			 * rx buffer, these required bits will be restored.
178 			 */
179 			if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
180 				hdr->flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
181 				flags_to_restore |= VIRTIO_VSOCK_SEQ_EOM;
182 
183 				if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR) {
184 					hdr->flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
185 					flags_to_restore |= VIRTIO_VSOCK_SEQ_EOR;
186 				}
187 			}
188 		}
189 
190 		/* Set the correct length in the header */
191 		hdr->len = cpu_to_le32(payload_len);
192 
193 		nbytes = copy_to_iter(hdr, sizeof(*hdr), &iov_iter);
194 		if (nbytes != sizeof(*hdr)) {
195 			kfree_skb(skb);
196 			vq_err(vq, "Faulted on copying pkt hdr\n");
197 			break;
198 		}
199 
200 		nbytes = copy_to_iter(skb->data, payload_len, &iov_iter);
201 		if (nbytes != payload_len) {
202 			kfree_skb(skb);
203 			vq_err(vq, "Faulted on copying pkt buf\n");
204 			break;
205 		}
206 
207 		/* Deliver to monitoring devices all packets that we
208 		 * will transmit.
209 		 */
210 		virtio_transport_deliver_tap_pkt(skb);
211 
212 		vhost_add_used(vq, head, sizeof(*hdr) + payload_len);
213 		added = true;
214 
215 		skb_pull(skb, payload_len);
216 		total_len += payload_len;
217 
218 		/* If we didn't send all the payload we can requeue the packet
219 		 * to send it with the next available buffer.
220 		 */
221 		if (skb->len > 0) {
222 			hdr->flags |= cpu_to_le32(flags_to_restore);
223 
224 			/* We are queueing the same skb to handle
225 			 * the remaining bytes, and we want to deliver it
226 			 * to monitoring devices in the next iteration.
227 			 */
228 			virtio_vsock_skb_clear_tap_delivered(skb);
229 			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
230 		} else {
231 			if (virtio_vsock_skb_reply(skb)) {
232 				int val;
233 
234 				val = atomic_dec_return(&vsock->queued_replies);
235 
236 				/* Do we have resources to resume tx
237 				 * processing?
238 				 */
239 				if (val + 1 == tx_vq->num)
240 					restart_tx = true;
241 			}
242 
243 			consume_skb(skb);
244 		}
245 	} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
246 	if (added)
247 		vhost_signal(&vsock->dev, vq);
248 
249 out:
250 	mutex_unlock(&vq->mutex);
251 
252 	if (restart_tx)
253 		vhost_poll_queue(&tx_vq->poll);
254 }
255 
256 static void vhost_transport_send_pkt_work(struct vhost_work *work)
257 {
258 	struct vhost_virtqueue *vq;
259 	struct vhost_vsock *vsock;
260 
261 	vsock = container_of(work, struct vhost_vsock, send_pkt_work);
262 	vq = &vsock->vqs[VSOCK_VQ_RX];
263 
264 	vhost_transport_do_send_pkt(vsock, vq);
265 }
266 
267 static int
268 vhost_transport_send_pkt(struct sk_buff *skb)
269 {
270 	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
271 	struct vhost_vsock *vsock;
272 	int len = skb->len;
273 
274 	rcu_read_lock();
275 
276 	/* Find the vhost_vsock according to guest context id  */
277 	vsock = vhost_vsock_get(le64_to_cpu(hdr->dst_cid));
278 	if (!vsock) {
279 		rcu_read_unlock();
280 		kfree_skb(skb);
281 		return -ENODEV;
282 	}
283 
284 	if (virtio_vsock_skb_reply(skb))
285 		atomic_inc(&vsock->queued_replies);
286 
287 	virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);
288 	vhost_vq_work_queue(&vsock->vqs[VSOCK_VQ_RX], &vsock->send_pkt_work);
289 
290 	rcu_read_unlock();
291 	return len;
292 }
293 
294 static int
295 vhost_transport_cancel_pkt(struct vsock_sock *vsk)
296 {
297 	struct vhost_vsock *vsock;
298 	int cnt = 0;
299 	int ret = -ENODEV;
300 
301 	rcu_read_lock();
302 
303 	/* Find the vhost_vsock according to guest context id  */
304 	vsock = vhost_vsock_get(vsk->remote_addr.svm_cid);
305 	if (!vsock)
306 		goto out;
307 
308 	cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue);
309 
310 	if (cnt) {
311 		struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
312 		int new_cnt;
313 
314 		new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
315 		if (new_cnt + cnt >= tx_vq->num && new_cnt < tx_vq->num)
316 			vhost_poll_queue(&tx_vq->poll);
317 	}
318 
319 	ret = 0;
320 out:
321 	rcu_read_unlock();
322 	return ret;
323 }
324 
325 static struct sk_buff *
326 vhost_vsock_alloc_skb(struct vhost_virtqueue *vq,
327 		      unsigned int out, unsigned int in)
328 {
329 	struct virtio_vsock_hdr *hdr;
330 	struct iov_iter iov_iter;
331 	struct sk_buff *skb;
332 	size_t payload_len;
333 	size_t nbytes;
334 	size_t len;
335 
336 	if (in != 0) {
337 		vq_err(vq, "Expected 0 input buffers, got %u\n", in);
338 		return NULL;
339 	}
340 
341 	len = iov_length(vq->iov, out);
342 
343 	/* len contains both payload and hdr */
344 	skb = virtio_vsock_alloc_skb(len, GFP_KERNEL);
345 	if (!skb)
346 		return NULL;
347 
348 	iov_iter_init(&iov_iter, ITER_SOURCE, vq->iov, out, len);
349 
350 	hdr = virtio_vsock_hdr(skb);
351 	nbytes = copy_from_iter(hdr, sizeof(*hdr), &iov_iter);
352 	if (nbytes != sizeof(*hdr)) {
353 		vq_err(vq, "Expected %zu bytes for pkt->hdr, got %zu bytes\n",
354 		       sizeof(*hdr), nbytes);
355 		kfree_skb(skb);
356 		return NULL;
357 	}
358 
359 	payload_len = le32_to_cpu(hdr->len);
360 
361 	/* No payload */
362 	if (!payload_len)
363 		return skb;
364 
365 	/* The pkt is too big or the length in the header is invalid */
366 	if (payload_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE ||
367 	    payload_len + sizeof(*hdr) > len) {
368 		kfree_skb(skb);
369 		return NULL;
370 	}
371 
372 	virtio_vsock_skb_rx_put(skb);
373 
374 	nbytes = copy_from_iter(skb->data, payload_len, &iov_iter);
375 	if (nbytes != payload_len) {
376 		vq_err(vq, "Expected %zu byte payload, got %zu bytes\n",
377 		       payload_len, nbytes);
378 		kfree_skb(skb);
379 		return NULL;
380 	}
381 
382 	return skb;
383 }
384 
385 /* Is there space left for replies to rx packets? */
386 static bool vhost_vsock_more_replies(struct vhost_vsock *vsock)
387 {
388 	struct vhost_virtqueue *vq = &vsock->vqs[VSOCK_VQ_TX];
389 	int val;
390 
391 	smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
392 	val = atomic_read(&vsock->queued_replies);
393 
394 	return val < vq->num;
395 }
396 
397 static bool vhost_transport_seqpacket_allow(u32 remote_cid);
398 
399 static struct virtio_transport vhost_transport = {
400 	.transport = {
401 		.module                   = THIS_MODULE,
402 
403 		.get_local_cid            = vhost_transport_get_local_cid,
404 
405 		.init                     = virtio_transport_do_socket_init,
406 		.destruct                 = virtio_transport_destruct,
407 		.release                  = virtio_transport_release,
408 		.connect                  = virtio_transport_connect,
409 		.shutdown                 = virtio_transport_shutdown,
410 		.cancel_pkt               = vhost_transport_cancel_pkt,
411 
412 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
413 		.dgram_dequeue            = virtio_transport_dgram_dequeue,
414 		.dgram_bind               = virtio_transport_dgram_bind,
415 		.dgram_allow              = virtio_transport_dgram_allow,
416 
417 		.stream_enqueue           = virtio_transport_stream_enqueue,
418 		.stream_dequeue           = virtio_transport_stream_dequeue,
419 		.stream_has_data          = virtio_transport_stream_has_data,
420 		.stream_has_space         = virtio_transport_stream_has_space,
421 		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
422 		.stream_is_active         = virtio_transport_stream_is_active,
423 		.stream_allow             = virtio_transport_stream_allow,
424 
425 		.seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,
426 		.seqpacket_enqueue        = virtio_transport_seqpacket_enqueue,
427 		.seqpacket_allow          = vhost_transport_seqpacket_allow,
428 		.seqpacket_has_data       = virtio_transport_seqpacket_has_data,
429 
430 		.notify_poll_in           = virtio_transport_notify_poll_in,
431 		.notify_poll_out          = virtio_transport_notify_poll_out,
432 		.notify_recv_init         = virtio_transport_notify_recv_init,
433 		.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
434 		.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
435 		.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
436 		.notify_send_init         = virtio_transport_notify_send_init,
437 		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
438 		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
439 		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
440 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
441 
442 		.read_skb = virtio_transport_read_skb,
443 	},
444 
445 	.send_pkt = vhost_transport_send_pkt,
446 };
447 
448 static bool vhost_transport_seqpacket_allow(u32 remote_cid)
449 {
450 	struct vhost_vsock *vsock;
451 	bool seqpacket_allow = false;
452 
453 	rcu_read_lock();
454 	vsock = vhost_vsock_get(remote_cid);
455 
456 	if (vsock)
457 		seqpacket_allow = vsock->seqpacket_allow;
458 
459 	rcu_read_unlock();
460 
461 	return seqpacket_allow;
462 }
463 
464 static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
465 {
466 	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
467 						  poll.work);
468 	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
469 						 dev);
470 	int head, pkts = 0, total_len = 0;
471 	unsigned int out, in;
472 	struct sk_buff *skb;
473 	bool added = false;
474 
475 	mutex_lock(&vq->mutex);
476 
477 	if (!vhost_vq_get_backend(vq))
478 		goto out;
479 
480 	if (!vq_meta_prefetch(vq))
481 		goto out;
482 
483 	vhost_disable_notify(&vsock->dev, vq);
484 	do {
485 		struct virtio_vsock_hdr *hdr;
486 
487 		if (!vhost_vsock_more_replies(vsock)) {
488 			/* Stop tx until the device processes already
489 			 * pending replies.  Leave tx virtqueue
490 			 * callbacks disabled.
491 			 */
492 			goto no_more_replies;
493 		}
494 
495 		head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
496 					 &out, &in, NULL, NULL);
497 		if (head < 0)
498 			break;
499 
500 		if (head == vq->num) {
501 			if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
502 				vhost_disable_notify(&vsock->dev, vq);
503 				continue;
504 			}
505 			break;
506 		}
507 
508 		skb = vhost_vsock_alloc_skb(vq, out, in);
509 		if (!skb) {
510 			vq_err(vq, "Faulted on pkt\n");
511 			continue;
512 		}
513 
514 		total_len += sizeof(*hdr) + skb->len;
515 
516 		/* Deliver to monitoring devices all received packets */
517 		virtio_transport_deliver_tap_pkt(skb);
518 
519 		hdr = virtio_vsock_hdr(skb);
520 
521 		/* Only accept correctly addressed packets */
522 		if (le64_to_cpu(hdr->src_cid) == vsock->guest_cid &&
523 		    le64_to_cpu(hdr->dst_cid) ==
524 		    vhost_transport_get_local_cid())
525 			virtio_transport_recv_pkt(&vhost_transport, skb);
526 		else
527 			kfree_skb(skb);
528 
529 		vhost_add_used(vq, head, 0);
530 		added = true;
531 	} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
532 
533 no_more_replies:
534 	if (added)
535 		vhost_signal(&vsock->dev, vq);
536 
537 out:
538 	mutex_unlock(&vq->mutex);
539 }
540 
541 static void vhost_vsock_handle_rx_kick(struct vhost_work *work)
542 {
543 	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
544 						poll.work);
545 	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
546 						 dev);
547 
548 	vhost_transport_do_send_pkt(vsock, vq);
549 }
550 
551 static int vhost_vsock_start(struct vhost_vsock *vsock)
552 {
553 	struct vhost_virtqueue *vq;
554 	size_t i;
555 	int ret;
556 
557 	mutex_lock(&vsock->dev.mutex);
558 
559 	ret = vhost_dev_check_owner(&vsock->dev);
560 	if (ret)
561 		goto err;
562 
563 	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
564 		vq = &vsock->vqs[i];
565 
566 		mutex_lock(&vq->mutex);
567 
568 		if (!vhost_vq_access_ok(vq)) {
569 			ret = -EFAULT;
570 			goto err_vq;
571 		}
572 
573 		if (!vhost_vq_get_backend(vq)) {
574 			vhost_vq_set_backend(vq, vsock);
575 			ret = vhost_vq_init_access(vq);
576 			if (ret)
577 				goto err_vq;
578 		}
579 
580 		mutex_unlock(&vq->mutex);
581 	}
582 
583 	/* Some packets may have been queued before the device was started,
584 	 * let's kick the send worker to send them.
585 	 */
586 	vhost_vq_work_queue(&vsock->vqs[VSOCK_VQ_RX], &vsock->send_pkt_work);
587 
588 	mutex_unlock(&vsock->dev.mutex);
589 	return 0;
590 
591 err_vq:
592 	vhost_vq_set_backend(vq, NULL);
593 	mutex_unlock(&vq->mutex);
594 
595 	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
596 		vq = &vsock->vqs[i];
597 
598 		mutex_lock(&vq->mutex);
599 		vhost_vq_set_backend(vq, NULL);
600 		mutex_unlock(&vq->mutex);
601 	}
602 err:
603 	mutex_unlock(&vsock->dev.mutex);
604 	return ret;
605 }
606 
607 static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner)
608 {
609 	size_t i;
610 	int ret = 0;
611 
612 	mutex_lock(&vsock->dev.mutex);
613 
614 	if (check_owner) {
615 		ret = vhost_dev_check_owner(&vsock->dev);
616 		if (ret)
617 			goto err;
618 	}
619 
620 	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
621 		struct vhost_virtqueue *vq = &vsock->vqs[i];
622 
623 		mutex_lock(&vq->mutex);
624 		vhost_vq_set_backend(vq, NULL);
625 		mutex_unlock(&vq->mutex);
626 	}
627 
628 err:
629 	mutex_unlock(&vsock->dev.mutex);
630 	return ret;
631 }
632 
633 static void vhost_vsock_free(struct vhost_vsock *vsock)
634 {
635 	kvfree(vsock);
636 }
637 
638 static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
639 {
640 	struct vhost_virtqueue **vqs;
641 	struct vhost_vsock *vsock;
642 	int ret;
643 
644 	/* This struct is large and allocation could fail, fall back to vmalloc
645 	 * if there is no other way.
646 	 */
647 	vsock = kvmalloc(sizeof(*vsock), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
648 	if (!vsock)
649 		return -ENOMEM;
650 
651 	vqs = kmalloc_array(ARRAY_SIZE(vsock->vqs), sizeof(*vqs), GFP_KERNEL);
652 	if (!vqs) {
653 		ret = -ENOMEM;
654 		goto out;
655 	}
656 
657 	vsock->guest_cid = 0; /* no CID assigned yet */
658 
659 	atomic_set(&vsock->queued_replies, 0);
660 
661 	vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX];
662 	vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX];
663 	vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
664 	vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
665 
666 	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs),
667 		       UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT,
668 		       VHOST_VSOCK_WEIGHT, true, NULL);
669 
670 	file->private_data = vsock;
671 	skb_queue_head_init(&vsock->send_pkt_queue);
672 	vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work);
673 	return 0;
674 
675 out:
676 	vhost_vsock_free(vsock);
677 	return ret;
678 }
679 
680 static void vhost_vsock_flush(struct vhost_vsock *vsock)
681 {
682 	vhost_dev_flush(&vsock->dev);
683 }
684 
685 static void vhost_vsock_reset_orphans(struct sock *sk)
686 {
687 	struct vsock_sock *vsk = vsock_sk(sk);
688 
689 	/* vmci_transport.c doesn't take sk_lock here either.  At least we're
690 	 * under vsock_table_lock so the sock cannot disappear while we're
691 	 * executing.
692 	 */
693 
694 	/* If the peer is still valid, no need to reset connection */
695 	if (vhost_vsock_get(vsk->remote_addr.svm_cid))
696 		return;
697 
698 	/* If the close timeout is pending, let it expire.  This avoids races
699 	 * with the timeout callback.
700 	 */
701 	if (vsk->close_work_scheduled)
702 		return;
703 
704 	sock_set_flag(sk, SOCK_DONE);
705 	vsk->peer_shutdown = SHUTDOWN_MASK;
706 	sk->sk_state = SS_UNCONNECTED;
707 	sk->sk_err = ECONNRESET;
708 	sk_error_report(sk);
709 }
710 
711 static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
712 {
713 	struct vhost_vsock *vsock = file->private_data;
714 
715 	mutex_lock(&vhost_vsock_mutex);
716 	if (vsock->guest_cid)
717 		hash_del_rcu(&vsock->hash);
718 	mutex_unlock(&vhost_vsock_mutex);
719 
720 	/* Wait for other CPUs to finish using vsock */
721 	synchronize_rcu();
722 
723 	/* Iterating over all connections for all CIDs to find orphans is
724 	 * inefficient.  Room for improvement here. */
725 	vsock_for_each_connected_socket(&vhost_transport.transport,
726 					vhost_vsock_reset_orphans);
727 
728 	/* Don't check the owner, because we are in the release path, so we
729 	 * need to stop the vsock device in any case.
730 	 * vhost_vsock_stop() can not fail in this case, so we don't need to
731 	 * check the return code.
732 	 */
733 	vhost_vsock_stop(vsock, false);
734 	vhost_vsock_flush(vsock);
735 	vhost_dev_stop(&vsock->dev);
736 
737 	virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue);
738 
739 	vhost_dev_cleanup(&vsock->dev);
740 	kfree(vsock->dev.vqs);
741 	vhost_vsock_free(vsock);
742 	return 0;
743 }
744 
745 static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid)
746 {
747 	struct vhost_vsock *other;
748 
749 	/* Refuse reserved CIDs */
750 	if (guest_cid <= VMADDR_CID_HOST ||
751 	    guest_cid == U32_MAX)
752 		return -EINVAL;
753 
754 	/* 64-bit CIDs are not yet supported */
755 	if (guest_cid > U32_MAX)
756 		return -EINVAL;
757 
758 	/* Refuse if CID is assigned to the guest->host transport (i.e. nested
759 	 * VM), to make the loopback work.
760 	 */
761 	if (vsock_find_cid(guest_cid))
762 		return -EADDRINUSE;
763 
764 	/* Refuse if CID is already in use */
765 	mutex_lock(&vhost_vsock_mutex);
766 	other = vhost_vsock_get(guest_cid);
767 	if (other && other != vsock) {
768 		mutex_unlock(&vhost_vsock_mutex);
769 		return -EADDRINUSE;
770 	}
771 
772 	if (vsock->guest_cid)
773 		hash_del_rcu(&vsock->hash);
774 
775 	vsock->guest_cid = guest_cid;
776 	hash_add_rcu(vhost_vsock_hash, &vsock->hash, vsock->guest_cid);
777 	mutex_unlock(&vhost_vsock_mutex);
778 
779 	return 0;
780 }
781 
782 static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)
783 {
784 	struct vhost_virtqueue *vq;
785 	int i;
786 
787 	if (features & ~VHOST_VSOCK_FEATURES)
788 		return -EOPNOTSUPP;
789 
790 	mutex_lock(&vsock->dev.mutex);
791 	if ((features & (1 << VHOST_F_LOG_ALL)) &&
792 	    !vhost_log_access_ok(&vsock->dev)) {
793 		goto err;
794 	}
795 
796 	if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) {
797 		if (vhost_init_device_iotlb(&vsock->dev))
798 			goto err;
799 	}
800 
801 	if (features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET))
802 		vsock->seqpacket_allow = true;
803 
804 	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
805 		vq = &vsock->vqs[i];
806 		mutex_lock(&vq->mutex);
807 		vq->acked_features = features;
808 		mutex_unlock(&vq->mutex);
809 	}
810 	mutex_unlock(&vsock->dev.mutex);
811 	return 0;
812 
813 err:
814 	mutex_unlock(&vsock->dev.mutex);
815 	return -EFAULT;
816 }
817 
818 static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl,
819 				  unsigned long arg)
820 {
821 	struct vhost_vsock *vsock = f->private_data;
822 	void __user *argp = (void __user *)arg;
823 	u64 guest_cid;
824 	u64 features;
825 	int start;
826 	int r;
827 
828 	switch (ioctl) {
829 	case VHOST_VSOCK_SET_GUEST_CID:
830 		if (copy_from_user(&guest_cid, argp, sizeof(guest_cid)))
831 			return -EFAULT;
832 		return vhost_vsock_set_cid(vsock, guest_cid);
833 	case VHOST_VSOCK_SET_RUNNING:
834 		if (copy_from_user(&start, argp, sizeof(start)))
835 			return -EFAULT;
836 		if (start)
837 			return vhost_vsock_start(vsock);
838 		else
839 			return vhost_vsock_stop(vsock, true);
840 	case VHOST_GET_FEATURES:
841 		features = VHOST_VSOCK_FEATURES;
842 		if (copy_to_user(argp, &features, sizeof(features)))
843 			return -EFAULT;
844 		return 0;
845 	case VHOST_SET_FEATURES:
846 		if (copy_from_user(&features, argp, sizeof(features)))
847 			return -EFAULT;
848 		return vhost_vsock_set_features(vsock, features);
849 	case VHOST_GET_BACKEND_FEATURES:
850 		features = VHOST_VSOCK_BACKEND_FEATURES;
851 		if (copy_to_user(argp, &features, sizeof(features)))
852 			return -EFAULT;
853 		return 0;
854 	case VHOST_SET_BACKEND_FEATURES:
855 		if (copy_from_user(&features, argp, sizeof(features)))
856 			return -EFAULT;
857 		if (features & ~VHOST_VSOCK_BACKEND_FEATURES)
858 			return -EOPNOTSUPP;
859 		vhost_set_backend_features(&vsock->dev, features);
860 		return 0;
861 	default:
862 		mutex_lock(&vsock->dev.mutex);
863 		r = vhost_dev_ioctl(&vsock->dev, ioctl, argp);
864 		if (r == -ENOIOCTLCMD)
865 			r = vhost_vring_ioctl(&vsock->dev, ioctl, argp);
866 		else
867 			vhost_vsock_flush(vsock);
868 		mutex_unlock(&vsock->dev.mutex);
869 		return r;
870 	}
871 }
872 
873 static ssize_t vhost_vsock_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
874 {
875 	struct file *file = iocb->ki_filp;
876 	struct vhost_vsock *vsock = file->private_data;
877 	struct vhost_dev *dev = &vsock->dev;
878 	int noblock = file->f_flags & O_NONBLOCK;
879 
880 	return vhost_chr_read_iter(dev, to, noblock);
881 }
882 
883 static ssize_t vhost_vsock_chr_write_iter(struct kiocb *iocb,
884 					struct iov_iter *from)
885 {
886 	struct file *file = iocb->ki_filp;
887 	struct vhost_vsock *vsock = file->private_data;
888 	struct vhost_dev *dev = &vsock->dev;
889 
890 	return vhost_chr_write_iter(dev, from);
891 }
892 
893 static __poll_t vhost_vsock_chr_poll(struct file *file, poll_table *wait)
894 {
895 	struct vhost_vsock *vsock = file->private_data;
896 	struct vhost_dev *dev = &vsock->dev;
897 
898 	return vhost_chr_poll(file, dev, wait);
899 }
900 
901 static const struct file_operations vhost_vsock_fops = {
902 	.owner          = THIS_MODULE,
903 	.open           = vhost_vsock_dev_open,
904 	.release        = vhost_vsock_dev_release,
905 	.llseek		= noop_llseek,
906 	.unlocked_ioctl = vhost_vsock_dev_ioctl,
907 	.compat_ioctl   = compat_ptr_ioctl,
908 	.read_iter      = vhost_vsock_chr_read_iter,
909 	.write_iter     = vhost_vsock_chr_write_iter,
910 	.poll           = vhost_vsock_chr_poll,
911 };
912 
913 static struct miscdevice vhost_vsock_misc = {
914 	.minor = VHOST_VSOCK_MINOR,
915 	.name = "vhost-vsock",
916 	.fops = &vhost_vsock_fops,
917 };
918 
919 static int __init vhost_vsock_init(void)
920 {
921 	int ret;
922 
923 	ret = vsock_core_register(&vhost_transport.transport,
924 				  VSOCK_TRANSPORT_F_H2G);
925 	if (ret < 0)
926 		return ret;
927 
928 	ret = misc_register(&vhost_vsock_misc);
929 	if (ret) {
930 		vsock_core_unregister(&vhost_transport.transport);
931 		return ret;
932 	}
933 
934 	return 0;
935 };
936 
937 static void __exit vhost_vsock_exit(void)
938 {
939 	misc_deregister(&vhost_vsock_misc);
940 	vsock_core_unregister(&vhost_transport.transport);
941 };
942 
943 module_init(vhost_vsock_init);
944 module_exit(vhost_vsock_exit);
945 MODULE_LICENSE("GPL v2");
946 MODULE_AUTHOR("Asias He");
947 MODULE_DESCRIPTION("vhost transport for vsock ");
948 MODULE_ALIAS_MISCDEV(VHOST_VSOCK_MINOR);
949 MODULE_ALIAS("devname:vhost-vsock");
950