1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * virtio transport for vsock 4 * 5 * Copyright (C) 2013-2015 Red Hat, Inc. 6 * Author: Asias He <asias@redhat.com> 7 * Stefan Hajnoczi <stefanha@redhat.com> 8 * 9 * Some of the code is take from Gerd Hoffmann <kraxel@redhat.com>'s 10 * early virtio-vsock proof-of-concept bits. 11 */ 12 #include <linux/spinlock.h> 13 #include <linux/module.h> 14 #include <linux/list.h> 15 #include <linux/atomic.h> 16 #include <linux/virtio.h> 17 #include <linux/virtio_ids.h> 18 #include <linux/virtio_config.h> 19 #include <linux/virtio_vsock.h> 20 #include <net/sock.h> 21 #include <linux/mutex.h> 22 #include <net/af_vsock.h> 23 24 static struct workqueue_struct *virtio_vsock_workqueue; 25 static struct virtio_vsock __rcu *the_virtio_vsock; 26 static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */ 27 static struct virtio_transport virtio_transport; /* forward declaration */ 28 29 struct virtio_vsock { 30 struct virtio_device *vdev; 31 struct virtqueue *vqs[VSOCK_VQ_MAX]; 32 33 /* Virtqueue processing is deferred to a workqueue */ 34 struct work_struct tx_work; 35 struct work_struct rx_work; 36 struct work_struct event_work; 37 38 /* The following fields are protected by tx_lock. vqs[VSOCK_VQ_TX] 39 * must be accessed with tx_lock held. 40 */ 41 struct mutex tx_lock; 42 bool tx_run; 43 44 struct work_struct send_pkt_work; 45 struct sk_buff_head send_pkt_queue; 46 47 atomic_t queued_replies; 48 49 /* The following fields are protected by rx_lock. vqs[VSOCK_VQ_RX] 50 * must be accessed with rx_lock held. 51 */ 52 struct mutex rx_lock; 53 bool rx_run; 54 int rx_buf_nr; 55 int rx_buf_max_nr; 56 57 /* The following fields are protected by event_lock. 58 * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held. 59 */ 60 struct mutex event_lock; 61 bool event_run; 62 struct virtio_vsock_event event_list[8]; 63 64 u32 guest_cid; 65 bool seqpacket_allow; 66 67 /* These fields are used only in tx path in function 68 * 'virtio_transport_send_pkt_work()', so to save 69 * stack space in it, place both of them here. Each 70 * pointer from 'out_sgs' points to the corresponding 71 * element in 'out_bufs' - this is initialized in 72 * 'virtio_vsock_probe()'. Both fields are protected 73 * by 'tx_lock'. +1 is needed for packet header. 74 */ 75 struct scatterlist *out_sgs[MAX_SKB_FRAGS + 1]; 76 struct scatterlist out_bufs[MAX_SKB_FRAGS + 1]; 77 }; 78 79 static u32 virtio_transport_get_local_cid(void) 80 { 81 struct virtio_vsock *vsock; 82 u32 ret; 83 84 rcu_read_lock(); 85 vsock = rcu_dereference(the_virtio_vsock); 86 if (!vsock) { 87 ret = VMADDR_CID_ANY; 88 goto out_rcu; 89 } 90 91 ret = vsock->guest_cid; 92 out_rcu: 93 rcu_read_unlock(); 94 return ret; 95 } 96 97 static void 98 virtio_transport_send_pkt_work(struct work_struct *work) 99 { 100 struct virtio_vsock *vsock = 101 container_of(work, struct virtio_vsock, send_pkt_work); 102 struct virtqueue *vq; 103 bool added = false; 104 bool restart_rx = false; 105 106 mutex_lock(&vsock->tx_lock); 107 108 if (!vsock->tx_run) 109 goto out; 110 111 vq = vsock->vqs[VSOCK_VQ_TX]; 112 113 for (;;) { 114 int ret, in_sg = 0, out_sg = 0; 115 struct scatterlist **sgs; 116 struct sk_buff *skb; 117 bool reply; 118 119 skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue); 120 if (!skb) 121 break; 122 123 virtio_transport_deliver_tap_pkt(skb); 124 reply = virtio_vsock_skb_reply(skb); 125 sgs = vsock->out_sgs; 126 sg_init_one(sgs[out_sg], virtio_vsock_hdr(skb), 127 sizeof(*virtio_vsock_hdr(skb))); 128 out_sg++; 129 130 if (!skb_is_nonlinear(skb)) { 131 if (skb->len > 0) { 132 sg_init_one(sgs[out_sg], skb->data, skb->len); 133 out_sg++; 134 } 135 } else { 136 struct skb_shared_info *si; 137 int i; 138 139 /* If skb is nonlinear, then its buffer must contain 140 * only header and nothing more. Data is stored in 141 * the fragged part. 142 */ 143 WARN_ON_ONCE(skb_headroom(skb) != sizeof(*virtio_vsock_hdr(skb))); 144 145 si = skb_shinfo(skb); 146 147 for (i = 0; i < si->nr_frags; i++) { 148 skb_frag_t *skb_frag = &si->frags[i]; 149 void *va; 150 151 /* We will use 'page_to_virt()' for the userspace page 152 * here, because virtio or dma-mapping layers will call 153 * 'virt_to_phys()' later to fill the buffer descriptor. 154 * We don't touch memory at "virtual" address of this page. 155 */ 156 va = page_to_virt(skb_frag->bv_page); 157 sg_init_one(sgs[out_sg], 158 va + skb_frag->bv_offset, 159 skb_frag->bv_len); 160 out_sg++; 161 } 162 } 163 164 ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL); 165 /* Usually this means that there is no more space available in 166 * the vq 167 */ 168 if (ret < 0) { 169 virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb); 170 break; 171 } 172 173 if (reply) { 174 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX]; 175 int val; 176 177 val = atomic_dec_return(&vsock->queued_replies); 178 179 /* Do we now have resources to resume rx processing? */ 180 if (val + 1 == virtqueue_get_vring_size(rx_vq)) 181 restart_rx = true; 182 } 183 184 added = true; 185 } 186 187 if (added) 188 virtqueue_kick(vq); 189 190 out: 191 mutex_unlock(&vsock->tx_lock); 192 193 if (restart_rx) 194 queue_work(virtio_vsock_workqueue, &vsock->rx_work); 195 } 196 197 static int 198 virtio_transport_send_pkt(struct sk_buff *skb) 199 { 200 struct virtio_vsock_hdr *hdr; 201 struct virtio_vsock *vsock; 202 int len = skb->len; 203 204 hdr = virtio_vsock_hdr(skb); 205 206 rcu_read_lock(); 207 vsock = rcu_dereference(the_virtio_vsock); 208 if (!vsock) { 209 kfree_skb(skb); 210 len = -ENODEV; 211 goto out_rcu; 212 } 213 214 if (le64_to_cpu(hdr->dst_cid) == vsock->guest_cid) { 215 kfree_skb(skb); 216 len = -ENODEV; 217 goto out_rcu; 218 } 219 220 if (virtio_vsock_skb_reply(skb)) 221 atomic_inc(&vsock->queued_replies); 222 223 virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb); 224 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work); 225 226 out_rcu: 227 rcu_read_unlock(); 228 return len; 229 } 230 231 static int 232 virtio_transport_cancel_pkt(struct vsock_sock *vsk) 233 { 234 struct virtio_vsock *vsock; 235 int cnt = 0, ret; 236 237 rcu_read_lock(); 238 vsock = rcu_dereference(the_virtio_vsock); 239 if (!vsock) { 240 ret = -ENODEV; 241 goto out_rcu; 242 } 243 244 cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue); 245 246 if (cnt) { 247 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX]; 248 int new_cnt; 249 250 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies); 251 if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) && 252 new_cnt < virtqueue_get_vring_size(rx_vq)) 253 queue_work(virtio_vsock_workqueue, &vsock->rx_work); 254 } 255 256 ret = 0; 257 258 out_rcu: 259 rcu_read_unlock(); 260 return ret; 261 } 262 263 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock) 264 { 265 int total_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM; 266 struct scatterlist pkt, *p; 267 struct virtqueue *vq; 268 struct sk_buff *skb; 269 int ret; 270 271 vq = vsock->vqs[VSOCK_VQ_RX]; 272 273 do { 274 skb = virtio_vsock_alloc_skb(total_len, GFP_KERNEL); 275 if (!skb) 276 break; 277 278 memset(skb->head, 0, VIRTIO_VSOCK_SKB_HEADROOM); 279 sg_init_one(&pkt, virtio_vsock_hdr(skb), total_len); 280 p = &pkt; 281 ret = virtqueue_add_sgs(vq, &p, 0, 1, skb, GFP_KERNEL); 282 if (ret < 0) { 283 kfree_skb(skb); 284 break; 285 } 286 287 vsock->rx_buf_nr++; 288 } while (vq->num_free); 289 if (vsock->rx_buf_nr > vsock->rx_buf_max_nr) 290 vsock->rx_buf_max_nr = vsock->rx_buf_nr; 291 virtqueue_kick(vq); 292 } 293 294 static void virtio_transport_tx_work(struct work_struct *work) 295 { 296 struct virtio_vsock *vsock = 297 container_of(work, struct virtio_vsock, tx_work); 298 struct virtqueue *vq; 299 bool added = false; 300 301 vq = vsock->vqs[VSOCK_VQ_TX]; 302 mutex_lock(&vsock->tx_lock); 303 304 if (!vsock->tx_run) 305 goto out; 306 307 do { 308 struct sk_buff *skb; 309 unsigned int len; 310 311 virtqueue_disable_cb(vq); 312 while ((skb = virtqueue_get_buf(vq, &len)) != NULL) { 313 consume_skb(skb); 314 added = true; 315 } 316 } while (!virtqueue_enable_cb(vq)); 317 318 out: 319 mutex_unlock(&vsock->tx_lock); 320 321 if (added) 322 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work); 323 } 324 325 /* Is there space left for replies to rx packets? */ 326 static bool virtio_transport_more_replies(struct virtio_vsock *vsock) 327 { 328 struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX]; 329 int val; 330 331 smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */ 332 val = atomic_read(&vsock->queued_replies); 333 334 return val < virtqueue_get_vring_size(vq); 335 } 336 337 /* event_lock must be held */ 338 static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock, 339 struct virtio_vsock_event *event) 340 { 341 struct scatterlist sg; 342 struct virtqueue *vq; 343 344 vq = vsock->vqs[VSOCK_VQ_EVENT]; 345 346 sg_init_one(&sg, event, sizeof(*event)); 347 348 return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL); 349 } 350 351 /* event_lock must be held */ 352 static void virtio_vsock_event_fill(struct virtio_vsock *vsock) 353 { 354 size_t i; 355 356 for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) { 357 struct virtio_vsock_event *event = &vsock->event_list[i]; 358 359 virtio_vsock_event_fill_one(vsock, event); 360 } 361 362 virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]); 363 } 364 365 static void virtio_vsock_reset_sock(struct sock *sk) 366 { 367 /* vmci_transport.c doesn't take sk_lock here either. At least we're 368 * under vsock_table_lock so the sock cannot disappear while we're 369 * executing. 370 */ 371 372 sk->sk_state = TCP_CLOSE; 373 sk->sk_err = ECONNRESET; 374 sk_error_report(sk); 375 } 376 377 static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock) 378 { 379 struct virtio_device *vdev = vsock->vdev; 380 __le64 guest_cid; 381 382 vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid), 383 &guest_cid, sizeof(guest_cid)); 384 vsock->guest_cid = le64_to_cpu(guest_cid); 385 } 386 387 /* event_lock must be held */ 388 static void virtio_vsock_event_handle(struct virtio_vsock *vsock, 389 struct virtio_vsock_event *event) 390 { 391 switch (le32_to_cpu(event->id)) { 392 case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET: 393 virtio_vsock_update_guest_cid(vsock); 394 vsock_for_each_connected_socket(&virtio_transport.transport, 395 virtio_vsock_reset_sock); 396 break; 397 } 398 } 399 400 static void virtio_transport_event_work(struct work_struct *work) 401 { 402 struct virtio_vsock *vsock = 403 container_of(work, struct virtio_vsock, event_work); 404 struct virtqueue *vq; 405 406 vq = vsock->vqs[VSOCK_VQ_EVENT]; 407 408 mutex_lock(&vsock->event_lock); 409 410 if (!vsock->event_run) 411 goto out; 412 413 do { 414 struct virtio_vsock_event *event; 415 unsigned int len; 416 417 virtqueue_disable_cb(vq); 418 while ((event = virtqueue_get_buf(vq, &len)) != NULL) { 419 if (len == sizeof(*event)) 420 virtio_vsock_event_handle(vsock, event); 421 422 virtio_vsock_event_fill_one(vsock, event); 423 } 424 } while (!virtqueue_enable_cb(vq)); 425 426 virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]); 427 out: 428 mutex_unlock(&vsock->event_lock); 429 } 430 431 static void virtio_vsock_event_done(struct virtqueue *vq) 432 { 433 struct virtio_vsock *vsock = vq->vdev->priv; 434 435 if (!vsock) 436 return; 437 queue_work(virtio_vsock_workqueue, &vsock->event_work); 438 } 439 440 static void virtio_vsock_tx_done(struct virtqueue *vq) 441 { 442 struct virtio_vsock *vsock = vq->vdev->priv; 443 444 if (!vsock) 445 return; 446 queue_work(virtio_vsock_workqueue, &vsock->tx_work); 447 } 448 449 static void virtio_vsock_rx_done(struct virtqueue *vq) 450 { 451 struct virtio_vsock *vsock = vq->vdev->priv; 452 453 if (!vsock) 454 return; 455 queue_work(virtio_vsock_workqueue, &vsock->rx_work); 456 } 457 458 static bool virtio_transport_can_msgzerocopy(int bufs_num) 459 { 460 struct virtio_vsock *vsock; 461 bool res = false; 462 463 rcu_read_lock(); 464 465 vsock = rcu_dereference(the_virtio_vsock); 466 if (vsock) { 467 struct virtqueue *vq = vsock->vqs[VSOCK_VQ_TX]; 468 469 /* Check that tx queue is large enough to keep whole 470 * data to send. This is needed, because when there is 471 * not enough free space in the queue, current skb to 472 * send will be reinserted to the head of tx list of 473 * the socket to retry transmission later, so if skb 474 * is bigger than whole queue, it will be reinserted 475 * again and again, thus blocking other skbs to be sent. 476 * Each page of the user provided buffer will be added 477 * as a single buffer to the tx virtqueue, so compare 478 * number of pages against maximum capacity of the queue. 479 */ 480 if (bufs_num <= vq->num_max) 481 res = true; 482 } 483 484 rcu_read_unlock(); 485 486 return res; 487 } 488 489 static bool virtio_transport_msgzerocopy_allow(void) 490 { 491 return true; 492 } 493 494 static bool virtio_transport_seqpacket_allow(u32 remote_cid); 495 496 static struct virtio_transport virtio_transport = { 497 .transport = { 498 .module = THIS_MODULE, 499 500 .get_local_cid = virtio_transport_get_local_cid, 501 502 .init = virtio_transport_do_socket_init, 503 .destruct = virtio_transport_destruct, 504 .release = virtio_transport_release, 505 .connect = virtio_transport_connect, 506 .shutdown = virtio_transport_shutdown, 507 .cancel_pkt = virtio_transport_cancel_pkt, 508 509 .dgram_bind = virtio_transport_dgram_bind, 510 .dgram_dequeue = virtio_transport_dgram_dequeue, 511 .dgram_enqueue = virtio_transport_dgram_enqueue, 512 .dgram_allow = virtio_transport_dgram_allow, 513 514 .stream_dequeue = virtio_transport_stream_dequeue, 515 .stream_enqueue = virtio_transport_stream_enqueue, 516 .stream_has_data = virtio_transport_stream_has_data, 517 .stream_has_space = virtio_transport_stream_has_space, 518 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat, 519 .stream_is_active = virtio_transport_stream_is_active, 520 .stream_allow = virtio_transport_stream_allow, 521 522 .seqpacket_dequeue = virtio_transport_seqpacket_dequeue, 523 .seqpacket_enqueue = virtio_transport_seqpacket_enqueue, 524 .seqpacket_allow = virtio_transport_seqpacket_allow, 525 .seqpacket_has_data = virtio_transport_seqpacket_has_data, 526 527 .msgzerocopy_allow = virtio_transport_msgzerocopy_allow, 528 529 .notify_poll_in = virtio_transport_notify_poll_in, 530 .notify_poll_out = virtio_transport_notify_poll_out, 531 .notify_recv_init = virtio_transport_notify_recv_init, 532 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block, 533 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue, 534 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue, 535 .notify_send_init = virtio_transport_notify_send_init, 536 .notify_send_pre_block = virtio_transport_notify_send_pre_block, 537 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue, 538 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue, 539 .notify_buffer_size = virtio_transport_notify_buffer_size, 540 541 .read_skb = virtio_transport_read_skb, 542 }, 543 544 .send_pkt = virtio_transport_send_pkt, 545 .can_msgzerocopy = virtio_transport_can_msgzerocopy, 546 }; 547 548 static bool virtio_transport_seqpacket_allow(u32 remote_cid) 549 { 550 struct virtio_vsock *vsock; 551 bool seqpacket_allow; 552 553 seqpacket_allow = false; 554 rcu_read_lock(); 555 vsock = rcu_dereference(the_virtio_vsock); 556 if (vsock) 557 seqpacket_allow = vsock->seqpacket_allow; 558 rcu_read_unlock(); 559 560 return seqpacket_allow; 561 } 562 563 static void virtio_transport_rx_work(struct work_struct *work) 564 { 565 struct virtio_vsock *vsock = 566 container_of(work, struct virtio_vsock, rx_work); 567 struct virtqueue *vq; 568 569 vq = vsock->vqs[VSOCK_VQ_RX]; 570 571 mutex_lock(&vsock->rx_lock); 572 573 if (!vsock->rx_run) 574 goto out; 575 576 do { 577 virtqueue_disable_cb(vq); 578 for (;;) { 579 struct sk_buff *skb; 580 unsigned int len; 581 582 if (!virtio_transport_more_replies(vsock)) { 583 /* Stop rx until the device processes already 584 * pending replies. Leave rx virtqueue 585 * callbacks disabled. 586 */ 587 goto out; 588 } 589 590 skb = virtqueue_get_buf(vq, &len); 591 if (!skb) 592 break; 593 594 vsock->rx_buf_nr--; 595 596 /* Drop short/long packets */ 597 if (unlikely(len < sizeof(struct virtio_vsock_hdr) || 598 len > virtio_vsock_skb_len(skb))) { 599 kfree_skb(skb); 600 continue; 601 } 602 603 virtio_vsock_skb_rx_put(skb); 604 virtio_transport_deliver_tap_pkt(skb); 605 virtio_transport_recv_pkt(&virtio_transport, skb); 606 } 607 } while (!virtqueue_enable_cb(vq)); 608 609 out: 610 if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2) 611 virtio_vsock_rx_fill(vsock); 612 mutex_unlock(&vsock->rx_lock); 613 } 614 615 static int virtio_vsock_vqs_init(struct virtio_vsock *vsock) 616 { 617 struct virtio_device *vdev = vsock->vdev; 618 static const char * const names[] = { 619 "rx", 620 "tx", 621 "event", 622 }; 623 vq_callback_t *callbacks[] = { 624 virtio_vsock_rx_done, 625 virtio_vsock_tx_done, 626 virtio_vsock_event_done, 627 }; 628 int ret; 629 630 ret = virtio_find_vqs(vdev, VSOCK_VQ_MAX, vsock->vqs, callbacks, names, 631 NULL); 632 if (ret < 0) 633 return ret; 634 635 virtio_vsock_update_guest_cid(vsock); 636 637 virtio_device_ready(vdev); 638 639 mutex_lock(&vsock->tx_lock); 640 vsock->tx_run = true; 641 mutex_unlock(&vsock->tx_lock); 642 643 mutex_lock(&vsock->rx_lock); 644 virtio_vsock_rx_fill(vsock); 645 vsock->rx_run = true; 646 mutex_unlock(&vsock->rx_lock); 647 648 mutex_lock(&vsock->event_lock); 649 virtio_vsock_event_fill(vsock); 650 vsock->event_run = true; 651 mutex_unlock(&vsock->event_lock); 652 653 return 0; 654 } 655 656 static void virtio_vsock_vqs_del(struct virtio_vsock *vsock) 657 { 658 struct virtio_device *vdev = vsock->vdev; 659 struct sk_buff *skb; 660 661 /* Reset all connected sockets when the VQs disappear */ 662 vsock_for_each_connected_socket(&virtio_transport.transport, 663 virtio_vsock_reset_sock); 664 665 /* Stop all work handlers to make sure no one is accessing the device, 666 * so we can safely call virtio_reset_device(). 667 */ 668 mutex_lock(&vsock->rx_lock); 669 vsock->rx_run = false; 670 mutex_unlock(&vsock->rx_lock); 671 672 mutex_lock(&vsock->tx_lock); 673 vsock->tx_run = false; 674 mutex_unlock(&vsock->tx_lock); 675 676 mutex_lock(&vsock->event_lock); 677 vsock->event_run = false; 678 mutex_unlock(&vsock->event_lock); 679 680 /* Flush all device writes and interrupts, device will not use any 681 * more buffers. 682 */ 683 virtio_reset_device(vdev); 684 685 mutex_lock(&vsock->rx_lock); 686 while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX]))) 687 kfree_skb(skb); 688 mutex_unlock(&vsock->rx_lock); 689 690 mutex_lock(&vsock->tx_lock); 691 while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX]))) 692 kfree_skb(skb); 693 mutex_unlock(&vsock->tx_lock); 694 695 virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue); 696 697 /* Delete virtqueues and flush outstanding callbacks if any */ 698 vdev->config->del_vqs(vdev); 699 } 700 701 static int virtio_vsock_probe(struct virtio_device *vdev) 702 { 703 struct virtio_vsock *vsock = NULL; 704 int ret; 705 int i; 706 707 ret = mutex_lock_interruptible(&the_virtio_vsock_mutex); 708 if (ret) 709 return ret; 710 711 /* Only one virtio-vsock device per guest is supported */ 712 if (rcu_dereference_protected(the_virtio_vsock, 713 lockdep_is_held(&the_virtio_vsock_mutex))) { 714 ret = -EBUSY; 715 goto out; 716 } 717 718 vsock = kzalloc(sizeof(*vsock), GFP_KERNEL); 719 if (!vsock) { 720 ret = -ENOMEM; 721 goto out; 722 } 723 724 vsock->vdev = vdev; 725 726 vsock->rx_buf_nr = 0; 727 vsock->rx_buf_max_nr = 0; 728 atomic_set(&vsock->queued_replies, 0); 729 730 mutex_init(&vsock->tx_lock); 731 mutex_init(&vsock->rx_lock); 732 mutex_init(&vsock->event_lock); 733 skb_queue_head_init(&vsock->send_pkt_queue); 734 INIT_WORK(&vsock->rx_work, virtio_transport_rx_work); 735 INIT_WORK(&vsock->tx_work, virtio_transport_tx_work); 736 INIT_WORK(&vsock->event_work, virtio_transport_event_work); 737 INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work); 738 739 if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET)) 740 vsock->seqpacket_allow = true; 741 742 vdev->priv = vsock; 743 744 ret = virtio_vsock_vqs_init(vsock); 745 if (ret < 0) 746 goto out; 747 748 for (i = 0; i < ARRAY_SIZE(vsock->out_sgs); i++) 749 vsock->out_sgs[i] = &vsock->out_bufs[i]; 750 751 rcu_assign_pointer(the_virtio_vsock, vsock); 752 753 mutex_unlock(&the_virtio_vsock_mutex); 754 755 return 0; 756 757 out: 758 kfree(vsock); 759 mutex_unlock(&the_virtio_vsock_mutex); 760 return ret; 761 } 762 763 static void virtio_vsock_remove(struct virtio_device *vdev) 764 { 765 struct virtio_vsock *vsock = vdev->priv; 766 767 mutex_lock(&the_virtio_vsock_mutex); 768 769 vdev->priv = NULL; 770 rcu_assign_pointer(the_virtio_vsock, NULL); 771 synchronize_rcu(); 772 773 virtio_vsock_vqs_del(vsock); 774 775 /* Other works can be queued before 'config->del_vqs()', so we flush 776 * all works before to free the vsock object to avoid use after free. 777 */ 778 flush_work(&vsock->rx_work); 779 flush_work(&vsock->tx_work); 780 flush_work(&vsock->event_work); 781 flush_work(&vsock->send_pkt_work); 782 783 mutex_unlock(&the_virtio_vsock_mutex); 784 785 kfree(vsock); 786 } 787 788 #ifdef CONFIG_PM_SLEEP 789 static int virtio_vsock_freeze(struct virtio_device *vdev) 790 { 791 struct virtio_vsock *vsock = vdev->priv; 792 793 mutex_lock(&the_virtio_vsock_mutex); 794 795 rcu_assign_pointer(the_virtio_vsock, NULL); 796 synchronize_rcu(); 797 798 virtio_vsock_vqs_del(vsock); 799 800 mutex_unlock(&the_virtio_vsock_mutex); 801 802 return 0; 803 } 804 805 static int virtio_vsock_restore(struct virtio_device *vdev) 806 { 807 struct virtio_vsock *vsock = vdev->priv; 808 int ret; 809 810 mutex_lock(&the_virtio_vsock_mutex); 811 812 /* Only one virtio-vsock device per guest is supported */ 813 if (rcu_dereference_protected(the_virtio_vsock, 814 lockdep_is_held(&the_virtio_vsock_mutex))) { 815 ret = -EBUSY; 816 goto out; 817 } 818 819 ret = virtio_vsock_vqs_init(vsock); 820 if (ret < 0) 821 goto out; 822 823 rcu_assign_pointer(the_virtio_vsock, vsock); 824 825 out: 826 mutex_unlock(&the_virtio_vsock_mutex); 827 return ret; 828 } 829 #endif /* CONFIG_PM_SLEEP */ 830 831 static struct virtio_device_id id_table[] = { 832 { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID }, 833 { 0 }, 834 }; 835 836 static unsigned int features[] = { 837 VIRTIO_VSOCK_F_SEQPACKET 838 }; 839 840 static struct virtio_driver virtio_vsock_driver = { 841 .feature_table = features, 842 .feature_table_size = ARRAY_SIZE(features), 843 .driver.name = KBUILD_MODNAME, 844 .driver.owner = THIS_MODULE, 845 .id_table = id_table, 846 .probe = virtio_vsock_probe, 847 .remove = virtio_vsock_remove, 848 #ifdef CONFIG_PM_SLEEP 849 .freeze = virtio_vsock_freeze, 850 .restore = virtio_vsock_restore, 851 #endif 852 }; 853 854 static int __init virtio_vsock_init(void) 855 { 856 int ret; 857 858 virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0); 859 if (!virtio_vsock_workqueue) 860 return -ENOMEM; 861 862 ret = vsock_core_register(&virtio_transport.transport, 863 VSOCK_TRANSPORT_F_G2H); 864 if (ret) 865 goto out_wq; 866 867 ret = register_virtio_driver(&virtio_vsock_driver); 868 if (ret) 869 goto out_vci; 870 871 return 0; 872 873 out_vci: 874 vsock_core_unregister(&virtio_transport.transport); 875 out_wq: 876 destroy_workqueue(virtio_vsock_workqueue); 877 return ret; 878 } 879 880 static void __exit virtio_vsock_exit(void) 881 { 882 unregister_virtio_driver(&virtio_vsock_driver); 883 vsock_core_unregister(&virtio_transport.transport); 884 destroy_workqueue(virtio_vsock_workqueue); 885 } 886 887 module_init(virtio_vsock_init); 888 module_exit(virtio_vsock_exit); 889 MODULE_LICENSE("GPL v2"); 890 MODULE_AUTHOR("Asias He"); 891 MODULE_DESCRIPTION("virtio transport for vsock"); 892 MODULE_DEVICE_TABLE(virtio, id_table); 893