net/vmw_vsock/virtio_transport.c

   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
  28 struct virtio_vsock {
  29         struct virtio_device *vdev;
  30         struct virtqueue *vqs[VSOCK_VQ_MAX];
  31
  32         /* Virtqueue processing is deferred to a workqueue */
  33         struct work_struct tx_work;
  34         struct work_struct rx_work;
  35         struct work_struct event_work;
  36
  37         /* The following fields are protected by tx_lock.  vqs[VSOCK_VQ_TX]
  38          * must be accessed with tx_lock held.
  39          */
  40         struct mutex tx_lock;
  41         bool tx_run;
  42
  43         struct work_struct send_pkt_work;
  44         spinlock_t send_pkt_list_lock;
  45         struct list_head send_pkt_list;
  46
  47         atomic_t queued_replies;
  48
  49         /* The following fields are protected by rx_lock.  vqs[VSOCK_VQ_RX]
  50          * must be accessed with rx_lock held.
  51          */
  52         struct mutex rx_lock;
  53         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 };
  66
  67 static u32 virtio_transport_get_local_cid(void)
  68 {
  69         struct virtio_vsock *vsock;
  70         u32 ret;
  71
  72         rcu_read_lock();
  73         vsock = rcu_dereference(the_virtio_vsock);
  74         if (!vsock) {
  75                 ret = VMADDR_CID_ANY;
  76                 goto out_rcu;
  77         }
  78
  79         ret = vsock->guest_cid;
  80 out_rcu:
  81         rcu_read_unlock();
  82         return ret;
  83 }
  84
  85 static void
  86 virtio_transport_send_pkt_work(struct work_struct *work)
  87 {
  88         struct virtio_vsock *vsock =
  89                 container_of(work, struct virtio_vsock, send_pkt_work);
  90         struct virtqueue *vq;
  91         bool added = false;
  92         bool restart_rx = false;
  93
  94         mutex_lock(&vsock->tx_lock);
  95
  96         if (!vsock->tx_run)
  97                 goto out;
  98
  99         vq = vsock->vqs[VSOCK_VQ_TX];
 100
 101         for (;;) {
 102                 struct virtio_vsock_pkt *pkt;
 103                 struct scatterlist hdr, buf, *sgs[2];
 104                 int ret, in_sg = 0, out_sg = 0;
 105                 bool reply;
 106
 107                 spin_lock_bh(&vsock->send_pkt_list_lock);
 108                 if (list_empty(&vsock->send_pkt_list)) {
 109                         spin_unlock_bh(&vsock->send_pkt_list_lock);
 110                         break;
 111                 }
 112
 113                 pkt = list_first_entry(&vsock->send_pkt_list,
 114                                        struct virtio_vsock_pkt, list);
 115                 list_del_init(&pkt->list);
 116                 spin_unlock_bh(&vsock->send_pkt_list_lock);
 117
 118                 virtio_transport_deliver_tap_pkt(pkt);
 119
 120                 reply = pkt->reply;
 121
 122                 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
 123                 sgs[out_sg++] = &hdr;
 124                 if (pkt->buf) {
 125                         sg_init_one(&buf, pkt->buf, pkt->len);
 126                         sgs[out_sg++] = &buf;
 127                 }
 128
 129                 ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
 130                 /* Usually this means that there is no more space available in
 131                  * the vq
 132                  */
 133                 if (ret < 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 (reply) {
 141                         struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 142                         int val;
 143
 144                         val = atomic_dec_return(&vsock->queued_replies);
 145
 146                         /* Do we now have resources to resume rx processing? */
 147                         if (val + 1 == virtqueue_get_vring_size(rx_vq))
 148                                 restart_rx = true;
 149                 }
 150
 151                 added = true;
 152         }
 153
 154         if (added)
 155                 virtqueue_kick(vq);
 156
 157 out:
 158         mutex_unlock(&vsock->tx_lock);
 159
 160         if (restart_rx)
 161                 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 162 }
 163
 164 static int
 165 virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
 166 {
 167         struct virtio_vsock *vsock;
 168         int len = pkt->len;
 169
 170         rcu_read_lock();
 171         vsock = rcu_dereference(the_virtio_vsock);
 172         if (!vsock) {
 173                 virtio_transport_free_pkt(pkt);
 174                 len = -ENODEV;
 175                 goto out_rcu;
 176         }
 177
 178         if (le64_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid) {
 179                 virtio_transport_free_pkt(pkt);
 180                 len = -ENODEV;
 181                 goto out_rcu;
 182         }
 183
 184         if (pkt->reply)
 185                 atomic_inc(&vsock->queued_replies);
 186
 187         spin_lock_bh(&vsock->send_pkt_list_lock);
 188         list_add_tail(&pkt->list, &vsock->send_pkt_list);
 189         spin_unlock_bh(&vsock->send_pkt_list_lock);
 190
 191         queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 192
 193 out_rcu:
 194         rcu_read_unlock();
 195         return len;
 196 }
 197
 198 static int
 199 virtio_transport_cancel_pkt(struct vsock_sock *vsk)
 200 {
 201         struct virtio_vsock *vsock;
 202         struct virtio_vsock_pkt *pkt, *n;
 203         int cnt = 0, ret;
 204         LIST_HEAD(freeme);
 205
 206         rcu_read_lock();
 207         vsock = rcu_dereference(the_virtio_vsock);
 208         if (!vsock) {
 209                 ret = -ENODEV;
 210                 goto out_rcu;
 211         }
 212
 213         spin_lock_bh(&vsock->send_pkt_list_lock);
 214         list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
 215                 if (pkt->vsk != vsk)
 216                         continue;
 217                 list_move(&pkt->list, &freeme);
 218         }
 219         spin_unlock_bh(&vsock->send_pkt_list_lock);
 220
 221         list_for_each_entry_safe(pkt, n, &freeme, list) {
 222                 if (pkt->reply)
 223                         cnt++;
 224                 list_del(&pkt->list);
 225                 virtio_transport_free_pkt(pkt);
 226         }
 227
 228         if (cnt) {
 229                 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 230                 int new_cnt;
 231
 232                 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
 233                 if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
 234                     new_cnt < virtqueue_get_vring_size(rx_vq))
 235                         queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 236         }
 237
 238         ret = 0;
 239
 240 out_rcu:
 241         rcu_read_unlock();
 242         return ret;
 243 }
 244
 245 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
 246 {
 247         int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
 248         struct virtio_vsock_pkt *pkt;
 249         struct scatterlist hdr, buf, *sgs[2];
 250         struct virtqueue *vq;
 251         int ret;
 252
 253         vq = vsock->vqs[VSOCK_VQ_RX];
 254
 255         do {
 256                 pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 257                 if (!pkt)
 258                         break;
 259
 260                 pkt->buf = kmalloc(buf_len, GFP_KERNEL);
 261                 if (!pkt->buf) {
 262                         virtio_transport_free_pkt(pkt);
 263                         break;
 264                 }
 265
 266                 pkt->buf_len = buf_len;
 267                 pkt->len = buf_len;
 268
 269                 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
 270                 sgs[0] = &hdr;
 271
 272                 sg_init_one(&buf, pkt->buf, buf_len);
 273                 sgs[1] = &buf;
 274                 ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
 275                 if (ret) {
 276                         virtio_transport_free_pkt(pkt);
 277                         break;
 278                 }
 279                 vsock->rx_buf_nr++;
 280         } while (vq->num_free);
 281         if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
 282                 vsock->rx_buf_max_nr = vsock->rx_buf_nr;
 283         virtqueue_kick(vq);
 284 }
 285
 286 static void virtio_transport_tx_work(struct work_struct *work)
 287 {
 288         struct virtio_vsock *vsock =
 289                 container_of(work, struct virtio_vsock, tx_work);
 290         struct virtqueue *vq;
 291         bool added = false;
 292
 293         vq = vsock->vqs[VSOCK_VQ_TX];
 294         mutex_lock(&vsock->tx_lock);
 295
 296         if (!vsock->tx_run)
 297                 goto out;
 298
 299         do {
 300                 struct virtio_vsock_pkt *pkt;
 301                 unsigned int len;
 302
 303                 virtqueue_disable_cb(vq);
 304                 while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
 305                         virtio_transport_free_pkt(pkt);
 306                         added = true;
 307                 }
 308         } while (!virtqueue_enable_cb(vq));
 309
 310 out:
 311         mutex_unlock(&vsock->tx_lock);
 312
 313         if (added)
 314                 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 315 }
 316
 317 /* Is there space left for replies to rx packets? */
 318 static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
 319 {
 320         struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
 321         int val;
 322
 323         smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
 324         val = atomic_read(&vsock->queued_replies);
 325
 326         return val < virtqueue_get_vring_size(vq);
 327 }
 328
 329 /* event_lock must be held */
 330 static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
 331                                        struct virtio_vsock_event *event)
 332 {
 333         struct scatterlist sg;
 334         struct virtqueue *vq;
 335
 336         vq = vsock->vqs[VSOCK_VQ_EVENT];
 337
 338         sg_init_one(&sg, event, sizeof(*event));
 339
 340         return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
 341 }
 342
 343 /* event_lock must be held */
 344 static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
 345 {
 346         size_t i;
 347
 348         for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
 349                 struct virtio_vsock_event *event = &vsock->event_list[i];
 350
 351                 virtio_vsock_event_fill_one(vsock, event);
 352         }
 353
 354         virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
 355 }
 356
 357 static void virtio_vsock_reset_sock(struct sock *sk)
 358 {
 359         lock_sock(sk);
 360         sk->sk_state = TCP_CLOSE;
 361         sk->sk_err = ECONNRESET;
 362         sk->sk_error_report(sk);
 363         release_sock(sk);
 364 }
 365
 366 static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
 367 {
 368         struct virtio_device *vdev = vsock->vdev;
 369         __le64 guest_cid;
 370
 371         vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
 372                           &guest_cid, sizeof(guest_cid));
 373         vsock->guest_cid = le64_to_cpu(guest_cid);
 374 }
 375
 376 /* event_lock must be held */
 377 static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
 378                                       struct virtio_vsock_event *event)
 379 {
 380         switch (le32_to_cpu(event->id)) {
 381         case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
 382                 virtio_vsock_update_guest_cid(vsock);
 383                 vsock_for_each_connected_socket(virtio_vsock_reset_sock);
 384                 break;
 385         }
 386 }
 387
 388 static void virtio_transport_event_work(struct work_struct *work)
 389 {
 390         struct virtio_vsock *vsock =
 391                 container_of(work, struct virtio_vsock, event_work);
 392         struct virtqueue *vq;
 393
 394         vq = vsock->vqs[VSOCK_VQ_EVENT];
 395
 396         mutex_lock(&vsock->event_lock);
 397
 398         if (!vsock->event_run)
 399                 goto out;
 400
 401         do {
 402                 struct virtio_vsock_event *event;
 403                 unsigned int len;
 404
 405                 virtqueue_disable_cb(vq);
 406                 while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
 407                         if (len == sizeof(*event))
 408                                 virtio_vsock_event_handle(vsock, event);
 409
 410                         virtio_vsock_event_fill_one(vsock, event);
 411                 }
 412         } while (!virtqueue_enable_cb(vq));
 413
 414         virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
 415 out:
 416         mutex_unlock(&vsock->event_lock);
 417 }
 418
 419 static void virtio_vsock_event_done(struct virtqueue *vq)
 420 {
 421         struct virtio_vsock *vsock = vq->vdev->priv;
 422
 423         if (!vsock)
 424                 return;
 425         queue_work(virtio_vsock_workqueue, &vsock->event_work);
 426 }
 427
 428 static void virtio_vsock_tx_done(struct virtqueue *vq)
 429 {
 430         struct virtio_vsock *vsock = vq->vdev->priv;
 431
 432         if (!vsock)
 433                 return;
 434         queue_work(virtio_vsock_workqueue, &vsock->tx_work);
 435 }
 436
 437 static void virtio_vsock_rx_done(struct virtqueue *vq)
 438 {
 439         struct virtio_vsock *vsock = vq->vdev->priv;
 440
 441         if (!vsock)
 442                 return;
 443         queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 444 }
 445
 446 static struct virtio_transport virtio_transport = {
 447         .transport = {
 448                 .module                   = THIS_MODULE,
 449
 450                 .get_local_cid            = virtio_transport_get_local_cid,
 451
 452                 .init                     = virtio_transport_do_socket_init,
 453                 .destruct                 = virtio_transport_destruct,
 454                 .release                  = virtio_transport_release,
 455                 .connect                  = virtio_transport_connect,
 456                 .shutdown                 = virtio_transport_shutdown,
 457                 .cancel_pkt               = virtio_transport_cancel_pkt,
 458
 459                 .dgram_bind               = virtio_transport_dgram_bind,
 460                 .dgram_dequeue            = virtio_transport_dgram_dequeue,
 461                 .dgram_enqueue            = virtio_transport_dgram_enqueue,
 462                 .dgram_allow              = virtio_transport_dgram_allow,
 463
 464                 .stream_dequeue           = virtio_transport_stream_dequeue,
 465                 .stream_enqueue           = virtio_transport_stream_enqueue,
 466                 .stream_has_data          = virtio_transport_stream_has_data,
 467                 .stream_has_space         = virtio_transport_stream_has_space,
 468                 .stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
 469                 .stream_is_active         = virtio_transport_stream_is_active,
 470                 .stream_allow             = virtio_transport_stream_allow,
 471
 472                 .notify_poll_in           = virtio_transport_notify_poll_in,
 473                 .notify_poll_out          = virtio_transport_notify_poll_out,
 474                 .notify_recv_init         = virtio_transport_notify_recv_init,
 475                 .notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
 476                 .notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
 477                 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
 478                 .notify_send_init         = virtio_transport_notify_send_init,
 479                 .notify_send_pre_block    = virtio_transport_notify_send_pre_block,
 480                 .notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
 481                 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
 482                 .notify_buffer_size       = virtio_transport_notify_buffer_size,
 483         },
 484
 485         .send_pkt = virtio_transport_send_pkt,
 486 };
 487
 488 static void virtio_transport_rx_work(struct work_struct *work)
 489 {
 490         struct virtio_vsock *vsock =
 491                 container_of(work, struct virtio_vsock, rx_work);
 492         struct virtqueue *vq;
 493
 494         vq = vsock->vqs[VSOCK_VQ_RX];
 495
 496         mutex_lock(&vsock->rx_lock);
 497
 498         if (!vsock->rx_run)
 499                 goto out;
 500
 501         do {
 502                 virtqueue_disable_cb(vq);
 503                 for (;;) {
 504                         struct virtio_vsock_pkt *pkt;
 505                         unsigned int len;
 506
 507                         if (!virtio_transport_more_replies(vsock)) {
 508                                 /* Stop rx until the device processes already
 509                                  * pending replies.  Leave rx virtqueue
 510                                  * callbacks disabled.
 511                                  */
 512                                 goto out;
 513                         }
 514
 515                         pkt = virtqueue_get_buf(vq, &len);
 516                         if (!pkt) {
 517                                 break;
 518                         }
 519
 520                         vsock->rx_buf_nr--;
 521
 522                         /* Drop short/long packets */
 523                         if (unlikely(len < sizeof(pkt->hdr) ||
 524                                      len > sizeof(pkt->hdr) + pkt->len)) {
 525                                 virtio_transport_free_pkt(pkt);
 526                                 continue;
 527                         }
 528
 529                         pkt->len = len - sizeof(pkt->hdr);
 530                         virtio_transport_deliver_tap_pkt(pkt);
 531                         virtio_transport_recv_pkt(&virtio_transport, pkt);
 532                 }
 533         } while (!virtqueue_enable_cb(vq));
 534
 535 out:
 536         if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
 537                 virtio_vsock_rx_fill(vsock);
 538         mutex_unlock(&vsock->rx_lock);
 539 }
 540
 541 static int virtio_vsock_probe(struct virtio_device *vdev)
 542 {
 543         vq_callback_t *callbacks[] = {
 544                 virtio_vsock_rx_done,
 545                 virtio_vsock_tx_done,
 546                 virtio_vsock_event_done,
 547         };
 548         static const char * const names[] = {
 549                 "rx",
 550                 "tx",
 551                 "event",
 552         };
 553         struct virtio_vsock *vsock = NULL;
 554         int ret;
 555
 556         ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
 557         if (ret)
 558                 return ret;
 559
 560         /* Only one virtio-vsock device per guest is supported */
 561         if (rcu_dereference_protected(the_virtio_vsock,
 562                                 lockdep_is_held(&the_virtio_vsock_mutex))) {
 563                 ret = -EBUSY;
 564                 goto out;
 565         }
 566
 567         vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
 568         if (!vsock) {
 569                 ret = -ENOMEM;
 570                 goto out;
 571         }
 572
 573         vsock->vdev = vdev;
 574
 575         ret = virtio_find_vqs(vsock->vdev, VSOCK_VQ_MAX,
 576                               vsock->vqs, callbacks, names,
 577                               NULL);
 578         if (ret < 0)
 579                 goto out;
 580
 581         virtio_vsock_update_guest_cid(vsock);
 582
 583         vsock->rx_buf_nr = 0;
 584         vsock->rx_buf_max_nr = 0;
 585         atomic_set(&vsock->queued_replies, 0);
 586
 587         mutex_init(&vsock->tx_lock);
 588         mutex_init(&vsock->rx_lock);
 589         mutex_init(&vsock->event_lock);
 590         spin_lock_init(&vsock->send_pkt_list_lock);
 591         INIT_LIST_HEAD(&vsock->send_pkt_list);
 592         INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
 593         INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
 594         INIT_WORK(&vsock->event_work, virtio_transport_event_work);
 595         INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
 596
 597         mutex_lock(&vsock->tx_lock);
 598         vsock->tx_run = true;
 599         mutex_unlock(&vsock->tx_lock);
 600
 601         mutex_lock(&vsock->rx_lock);
 602         virtio_vsock_rx_fill(vsock);
 603         vsock->rx_run = true;
 604         mutex_unlock(&vsock->rx_lock);
 605
 606         mutex_lock(&vsock->event_lock);
 607         virtio_vsock_event_fill(vsock);
 608         vsock->event_run = true;
 609         mutex_unlock(&vsock->event_lock);
 610
 611         vdev->priv = vsock;
 612         rcu_assign_pointer(the_virtio_vsock, vsock);
 613
 614         mutex_unlock(&the_virtio_vsock_mutex);
 615         return 0;
 616
 617 out:
 618         kfree(vsock);
 619         mutex_unlock(&the_virtio_vsock_mutex);
 620         return ret;
 621 }
 622
 623 static void virtio_vsock_remove(struct virtio_device *vdev)
 624 {
 625         struct virtio_vsock *vsock = vdev->priv;
 626         struct virtio_vsock_pkt *pkt;
 627
 628         mutex_lock(&the_virtio_vsock_mutex);
 629
 630         vdev->priv = NULL;
 631         rcu_assign_pointer(the_virtio_vsock, NULL);
 632         synchronize_rcu();
 633
 634         /* Reset all connected sockets when the device disappear */
 635         vsock_for_each_connected_socket(virtio_vsock_reset_sock);
 636
 637         /* Stop all work handlers to make sure no one is accessing the device,
 638          * so we can safely call vdev->config->reset().
 639          */
 640         mutex_lock(&vsock->rx_lock);
 641         vsock->rx_run = false;
 642         mutex_unlock(&vsock->rx_lock);
 643
 644         mutex_lock(&vsock->tx_lock);
 645         vsock->tx_run = false;
 646         mutex_unlock(&vsock->tx_lock);
 647
 648         mutex_lock(&vsock->event_lock);
 649         vsock->event_run = false;
 650         mutex_unlock(&vsock->event_lock);
 651
 652         /* Flush all device writes and interrupts, device will not use any
 653          * more buffers.
 654          */
 655         vdev->config->reset(vdev);
 656
 657         mutex_lock(&vsock->rx_lock);
 658         while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
 659                 virtio_transport_free_pkt(pkt);
 660         mutex_unlock(&vsock->rx_lock);
 661
 662         mutex_lock(&vsock->tx_lock);
 663         while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
 664                 virtio_transport_free_pkt(pkt);
 665         mutex_unlock(&vsock->tx_lock);
 666
 667         spin_lock_bh(&vsock->send_pkt_list_lock);
 668         while (!list_empty(&vsock->send_pkt_list)) {
 669                 pkt = list_first_entry(&vsock->send_pkt_list,
 670                                        struct virtio_vsock_pkt, list);
 671                 list_del(&pkt->list);
 672                 virtio_transport_free_pkt(pkt);
 673         }
 674         spin_unlock_bh(&vsock->send_pkt_list_lock);
 675
 676         /* Delete virtqueues and flush outstanding callbacks if any */
 677         vdev->config->del_vqs(vdev);
 678
 679         /* Other works can be queued before 'config->del_vqs()', so we flush
 680          * all works before to free the vsock object to avoid use after free.
 681          */
 682         flush_work(&vsock->rx_work);
 683         flush_work(&vsock->tx_work);
 684         flush_work(&vsock->event_work);
 685         flush_work(&vsock->send_pkt_work);
 686
 687         mutex_unlock(&the_virtio_vsock_mutex);
 688
 689         kfree(vsock);
 690 }
 691
 692 static struct virtio_device_id id_table[] = {
 693         { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
 694         { 0 },
 695 };
 696
 697 static unsigned int features[] = {
 698 };
 699
 700 static struct virtio_driver virtio_vsock_driver = {
 701         .feature_table = features,
 702         .feature_table_size = ARRAY_SIZE(features),
 703         .driver.name = KBUILD_MODNAME,
 704         .driver.owner = THIS_MODULE,
 705         .id_table = id_table,
 706         .probe = virtio_vsock_probe,
 707         .remove = virtio_vsock_remove,
 708 };
 709
 710 static int __init virtio_vsock_init(void)
 711 {
 712         int ret;
 713
 714         virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
 715         if (!virtio_vsock_workqueue)
 716                 return -ENOMEM;
 717
 718         ret = vsock_core_register(&virtio_transport.transport,
 719                                   VSOCK_TRANSPORT_F_G2H);
 720         if (ret)
 721                 goto out_wq;
 722
 723         ret = register_virtio_driver(&virtio_vsock_driver);
 724         if (ret)
 725                 goto out_vci;
 726
 727         return 0;
 728
 729 out_vci:
 730         vsock_core_unregister(&virtio_transport.transport);
 731 out_wq:
 732         destroy_workqueue(virtio_vsock_workqueue);
 733         return ret;
 734 }
 735
 736 static void __exit virtio_vsock_exit(void)
 737 {
 738         unregister_virtio_driver(&virtio_vsock_driver);
 739         vsock_core_unregister(&virtio_transport.transport);
 740         destroy_workqueue(virtio_vsock_workqueue);
 741 }
 742
 743 module_init(virtio_vsock_init);
 744 module_exit(virtio_vsock_exit);
 745 MODULE_LICENSE("GPL v2");
 746 MODULE_AUTHOR("Asias He");
 747 MODULE_DESCRIPTION("virtio transport for vsock");
 748 MODULE_DEVICE_TABLE(virtio, id_table);