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 *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
  42         struct work_struct send_pkt_work;
  43         spinlock_t send_pkt_list_lock;
  44         struct list_head send_pkt_list;
  45
  46         struct work_struct loopback_work;
  47         spinlock_t loopback_list_lock; /* protects loopback_list */
  48         struct list_head loopback_list;
  49
  50         atomic_t queued_replies;
  51
  52         /* The following fields are protected by rx_lock.  vqs[VSOCK_VQ_RX]
  53          * must be accessed with rx_lock held.
  54          */
  55         struct mutex rx_lock;
  56         int rx_buf_nr;
  57         int rx_buf_max_nr;
  58
  59         /* The following fields are protected by event_lock.
  60          * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
  61          */
  62         struct mutex event_lock;
  63         struct virtio_vsock_event event_list[8];
  64
  65         u32 guest_cid;
  66 };
  67
  68 static struct virtio_vsock *virtio_vsock_get(void)
  69 {
  70         return the_virtio_vsock;
  71 }
  72
  73 static u32 virtio_transport_get_local_cid(void)
  74 {
  75         struct virtio_vsock *vsock = virtio_vsock_get();
  76
  77         if (!vsock)
  78                 return VMADDR_CID_ANY;
  79
  80         return vsock->guest_cid;
  81 }
  82
  83 static void virtio_transport_loopback_work(struct work_struct *work)
  84 {
  85         struct virtio_vsock *vsock =
  86                 container_of(work, struct virtio_vsock, loopback_work);
  87         LIST_HEAD(pkts);
  88
  89         spin_lock_bh(&vsock->loopback_list_lock);
  90         list_splice_init(&vsock->loopback_list, &pkts);
  91         spin_unlock_bh(&vsock->loopback_list_lock);
  92
  93         mutex_lock(&vsock->rx_lock);
  94         while (!list_empty(&pkts)) {
  95                 struct virtio_vsock_pkt *pkt;
  96
  97                 pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
  98                 list_del_init(&pkt->list);
  99
 100                 virtio_transport_recv_pkt(pkt);
 101         }
 102         mutex_unlock(&vsock->rx_lock);
 103 }
 104
 105 static int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
 106                                               struct virtio_vsock_pkt *pkt)
 107 {
 108         int len = pkt->len;
 109
 110         spin_lock_bh(&vsock->loopback_list_lock);
 111         list_add_tail(&pkt->list, &vsock->loopback_list);
 112         spin_unlock_bh(&vsock->loopback_list_lock);
 113
 114         queue_work(virtio_vsock_workqueue, &vsock->loopback_work);
 115
 116         return len;
 117 }
 118
 119 static void
 120 virtio_transport_send_pkt_work(struct work_struct *work)
 121 {
 122         struct virtio_vsock *vsock =
 123                 container_of(work, struct virtio_vsock, send_pkt_work);
 124         struct virtqueue *vq;
 125         bool added = false;
 126         bool restart_rx = false;
 127
 128         mutex_lock(&vsock->tx_lock);
 129
 130         vq = vsock->vqs[VSOCK_VQ_TX];
 131
 132         for (;;) {
 133                 struct virtio_vsock_pkt *pkt;
 134                 struct scatterlist hdr, buf, *sgs[2];
 135                 int ret, in_sg = 0, out_sg = 0;
 136                 bool reply;
 137
 138                 spin_lock_bh(&vsock->send_pkt_list_lock);
 139                 if (list_empty(&vsock->send_pkt_list)) {
 140                         spin_unlock_bh(&vsock->send_pkt_list_lock);
 141                         break;
 142                 }
 143
 144                 pkt = list_first_entry(&vsock->send_pkt_list,
 145                                        struct virtio_vsock_pkt, list);
 146                 list_del_init(&pkt->list);
 147                 spin_unlock_bh(&vsock->send_pkt_list_lock);
 148
 149                 virtio_transport_deliver_tap_pkt(pkt);
 150
 151                 reply = pkt->reply;
 152
 153                 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
 154                 sgs[out_sg++] = &hdr;
 155                 if (pkt->buf) {
 156                         sg_init_one(&buf, pkt->buf, pkt->len);
 157                         sgs[out_sg++] = &buf;
 158                 }
 159
 160                 ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
 161                 /* Usually this means that there is no more space available in
 162                  * the vq
 163                  */
 164                 if (ret < 0) {
 165                         spin_lock_bh(&vsock->send_pkt_list_lock);
 166                         list_add(&pkt->list, &vsock->send_pkt_list);
 167                         spin_unlock_bh(&vsock->send_pkt_list_lock);
 168                         break;
 169                 }
 170
 171                 if (reply) {
 172                         struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 173                         int val;
 174
 175                         val = atomic_dec_return(&vsock->queued_replies);
 176
 177                         /* Do we now have resources to resume rx processing? */
 178                         if (val + 1 == virtqueue_get_vring_size(rx_vq))
 179                                 restart_rx = true;
 180                 }
 181
 182                 added = true;
 183         }
 184
 185         if (added)
 186                 virtqueue_kick(vq);
 187
 188         mutex_unlock(&vsock->tx_lock);
 189
 190         if (restart_rx)
 191                 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 192 }
 193
 194 static int
 195 virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
 196 {
 197         struct virtio_vsock *vsock;
 198         int len = pkt->len;
 199
 200         vsock = virtio_vsock_get();
 201         if (!vsock) {
 202                 virtio_transport_free_pkt(pkt);
 203                 return -ENODEV;
 204         }
 205
 206         if (le64_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid)
 207                 return virtio_transport_send_pkt_loopback(vsock, pkt);
 208
 209         if (pkt->reply)
 210                 atomic_inc(&vsock->queued_replies);
 211
 212         spin_lock_bh(&vsock->send_pkt_list_lock);
 213         list_add_tail(&pkt->list, &vsock->send_pkt_list);
 214         spin_unlock_bh(&vsock->send_pkt_list_lock);
 215
 216         queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 217         return len;
 218 }
 219
 220 static int
 221 virtio_transport_cancel_pkt(struct vsock_sock *vsk)
 222 {
 223         struct virtio_vsock *vsock;
 224         struct virtio_vsock_pkt *pkt, *n;
 225         int cnt = 0;
 226         LIST_HEAD(freeme);
 227
 228         vsock = virtio_vsock_get();
 229         if (!vsock) {
 230                 return -ENODEV;
 231         }
 232
 233         spin_lock_bh(&vsock->send_pkt_list_lock);
 234         list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
 235                 if (pkt->vsk != vsk)
 236                         continue;
 237                 list_move(&pkt->list, &freeme);
 238         }
 239         spin_unlock_bh(&vsock->send_pkt_list_lock);
 240
 241         list_for_each_entry_safe(pkt, n, &freeme, list) {
 242                 if (pkt->reply)
 243                         cnt++;
 244                 list_del(&pkt->list);
 245                 virtio_transport_free_pkt(pkt);
 246         }
 247
 248         if (cnt) {
 249                 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 250                 int new_cnt;
 251
 252                 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
 253                 if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
 254                     new_cnt < virtqueue_get_vring_size(rx_vq))
 255                         queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 256         }
 257
 258         return 0;
 259 }
 260
 261 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
 262 {
 263         int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
 264         struct virtio_vsock_pkt *pkt;
 265         struct scatterlist hdr, buf, *sgs[2];
 266         struct virtqueue *vq;
 267         int ret;
 268
 269         vq = vsock->vqs[VSOCK_VQ_RX];
 270
 271         do {
 272                 pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 273                 if (!pkt)
 274                         break;
 275
 276                 pkt->buf = kmalloc(buf_len, GFP_KERNEL);
 277                 if (!pkt->buf) {
 278                         virtio_transport_free_pkt(pkt);
 279                         break;
 280                 }
 281
 282                 pkt->len = buf_len;
 283
 284                 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
 285                 sgs[0] = &hdr;
 286
 287                 sg_init_one(&buf, pkt->buf, buf_len);
 288                 sgs[1] = &buf;
 289                 ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
 290                 if (ret) {
 291                         virtio_transport_free_pkt(pkt);
 292                         break;
 293                 }
 294                 vsock->rx_buf_nr++;
 295         } while (vq->num_free);
 296         if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
 297                 vsock->rx_buf_max_nr = vsock->rx_buf_nr;
 298         virtqueue_kick(vq);
 299 }
 300
 301 static void virtio_transport_tx_work(struct work_struct *work)
 302 {
 303         struct virtio_vsock *vsock =
 304                 container_of(work, struct virtio_vsock, tx_work);
 305         struct virtqueue *vq;
 306         bool added = false;
 307
 308         vq = vsock->vqs[VSOCK_VQ_TX];
 309         mutex_lock(&vsock->tx_lock);
 310         do {
 311                 struct virtio_vsock_pkt *pkt;
 312                 unsigned int len;
 313
 314                 virtqueue_disable_cb(vq);
 315                 while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
 316                         virtio_transport_free_pkt(pkt);
 317                         added = true;
 318                 }
 319         } while (!virtqueue_enable_cb(vq));
 320         mutex_unlock(&vsock->tx_lock);
 321
 322         if (added)
 323                 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 324 }
 325
 326 /* Is there space left for replies to rx packets? */
 327 static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
 328 {
 329         struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
 330         int val;
 331
 332         smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
 333         val = atomic_read(&vsock->queued_replies);
 334
 335         return val < virtqueue_get_vring_size(vq);
 336 }
 337
 338 static void virtio_transport_rx_work(struct work_struct *work)
 339 {
 340         struct virtio_vsock *vsock =
 341                 container_of(work, struct virtio_vsock, rx_work);
 342         struct virtqueue *vq;
 343
 344         vq = vsock->vqs[VSOCK_VQ_RX];
 345
 346         mutex_lock(&vsock->rx_lock);
 347
 348         do {
 349                 virtqueue_disable_cb(vq);
 350                 for (;;) {
 351                         struct virtio_vsock_pkt *pkt;
 352                         unsigned int len;
 353
 354                         if (!virtio_transport_more_replies(vsock)) {
 355                                 /* Stop rx until the device processes already
 356                                  * pending replies.  Leave rx virtqueue
 357                                  * callbacks disabled.
 358                                  */
 359                                 goto out;
 360                         }
 361
 362                         pkt = virtqueue_get_buf(vq, &len);
 363                         if (!pkt) {
 364                                 break;
 365                         }
 366
 367                         vsock->rx_buf_nr--;
 368
 369                         /* Drop short/long packets */
 370                         if (unlikely(len < sizeof(pkt->hdr) ||
 371                                      len > sizeof(pkt->hdr) + pkt->len)) {
 372                                 virtio_transport_free_pkt(pkt);
 373                                 continue;
 374                         }
 375
 376                         pkt->len = len - sizeof(pkt->hdr);
 377                         virtio_transport_deliver_tap_pkt(pkt);
 378                         virtio_transport_recv_pkt(pkt);
 379                 }
 380         } while (!virtqueue_enable_cb(vq));
 381
 382 out:
 383         if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
 384                 virtio_vsock_rx_fill(vsock);
 385         mutex_unlock(&vsock->rx_lock);
 386 }
 387
 388 /* event_lock must be held */
 389 static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
 390                                        struct virtio_vsock_event *event)
 391 {
 392         struct scatterlist sg;
 393         struct virtqueue *vq;
 394
 395         vq = vsock->vqs[VSOCK_VQ_EVENT];
 396
 397         sg_init_one(&sg, event, sizeof(*event));
 398
 399         return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
 400 }
 401
 402 /* event_lock must be held */
 403 static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
 404 {
 405         size_t i;
 406
 407         for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
 408                 struct virtio_vsock_event *event = &vsock->event_list[i];
 409
 410                 virtio_vsock_event_fill_one(vsock, event);
 411         }
 412
 413         virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
 414 }
 415
 416 static void virtio_vsock_reset_sock(struct sock *sk)
 417 {
 418         lock_sock(sk);
 419         sk->sk_state = TCP_CLOSE;
 420         sk->sk_err = ECONNRESET;
 421         sk->sk_error_report(sk);
 422         release_sock(sk);
 423 }
 424
 425 static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
 426 {
 427         struct virtio_device *vdev = vsock->vdev;
 428         __le64 guest_cid;
 429
 430         vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
 431                           &guest_cid, sizeof(guest_cid));
 432         vsock->guest_cid = le64_to_cpu(guest_cid);
 433 }
 434
 435 /* event_lock must be held */
 436 static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
 437                                       struct virtio_vsock_event *event)
 438 {
 439         switch (le32_to_cpu(event->id)) {
 440         case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
 441                 virtio_vsock_update_guest_cid(vsock);
 442                 vsock_for_each_connected_socket(virtio_vsock_reset_sock);
 443                 break;
 444         }
 445 }
 446
 447 static void virtio_transport_event_work(struct work_struct *work)
 448 {
 449         struct virtio_vsock *vsock =
 450                 container_of(work, struct virtio_vsock, event_work);
 451         struct virtqueue *vq;
 452
 453         vq = vsock->vqs[VSOCK_VQ_EVENT];
 454
 455         mutex_lock(&vsock->event_lock);
 456
 457         do {
 458                 struct virtio_vsock_event *event;
 459                 unsigned int len;
 460
 461                 virtqueue_disable_cb(vq);
 462                 while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
 463                         if (len == sizeof(*event))
 464                                 virtio_vsock_event_handle(vsock, event);
 465
 466                         virtio_vsock_event_fill_one(vsock, event);
 467                 }
 468         } while (!virtqueue_enable_cb(vq));
 469
 470         virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
 471
 472         mutex_unlock(&vsock->event_lock);
 473 }
 474
 475 static void virtio_vsock_event_done(struct virtqueue *vq)
 476 {
 477         struct virtio_vsock *vsock = vq->vdev->priv;
 478
 479         if (!vsock)
 480                 return;
 481         queue_work(virtio_vsock_workqueue, &vsock->event_work);
 482 }
 483
 484 static void virtio_vsock_tx_done(struct virtqueue *vq)
 485 {
 486         struct virtio_vsock *vsock = vq->vdev->priv;
 487
 488         if (!vsock)
 489                 return;
 490         queue_work(virtio_vsock_workqueue, &vsock->tx_work);
 491 }
 492
 493 static void virtio_vsock_rx_done(struct virtqueue *vq)
 494 {
 495         struct virtio_vsock *vsock = vq->vdev->priv;
 496
 497         if (!vsock)
 498                 return;
 499         queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 500 }
 501
 502 static struct virtio_transport virtio_transport = {
 503         .transport = {
 504                 .get_local_cid            = virtio_transport_get_local_cid,
 505
 506                 .init                     = virtio_transport_do_socket_init,
 507                 .destruct                 = virtio_transport_destruct,
 508                 .release                  = virtio_transport_release,
 509                 .connect                  = virtio_transport_connect,
 510                 .shutdown                 = virtio_transport_shutdown,
 511                 .cancel_pkt               = virtio_transport_cancel_pkt,
 512
 513                 .dgram_bind               = virtio_transport_dgram_bind,
 514                 .dgram_dequeue            = virtio_transport_dgram_dequeue,
 515                 .dgram_enqueue            = virtio_transport_dgram_enqueue,
 516                 .dgram_allow              = virtio_transport_dgram_allow,
 517
 518                 .stream_dequeue           = virtio_transport_stream_dequeue,
 519                 .stream_enqueue           = virtio_transport_stream_enqueue,
 520                 .stream_has_data          = virtio_transport_stream_has_data,
 521                 .stream_has_space         = virtio_transport_stream_has_space,
 522                 .stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
 523                 .stream_is_active         = virtio_transport_stream_is_active,
 524                 .stream_allow             = virtio_transport_stream_allow,
 525
 526                 .notify_poll_in           = virtio_transport_notify_poll_in,
 527                 .notify_poll_out          = virtio_transport_notify_poll_out,
 528                 .notify_recv_init         = virtio_transport_notify_recv_init,
 529                 .notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
 530                 .notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
 531                 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
 532                 .notify_send_init         = virtio_transport_notify_send_init,
 533                 .notify_send_pre_block    = virtio_transport_notify_send_pre_block,
 534                 .notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
 535                 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
 536
 537                 .set_buffer_size          = virtio_transport_set_buffer_size,
 538                 .set_min_buffer_size      = virtio_transport_set_min_buffer_size,
 539                 .set_max_buffer_size      = virtio_transport_set_max_buffer_size,
 540                 .get_buffer_size          = virtio_transport_get_buffer_size,
 541                 .get_min_buffer_size      = virtio_transport_get_min_buffer_size,
 542                 .get_max_buffer_size      = virtio_transport_get_max_buffer_size,
 543         },
 544
 545         .send_pkt = virtio_transport_send_pkt,
 546 };
 547
 548 static int virtio_vsock_probe(struct virtio_device *vdev)
 549 {
 550         vq_callback_t *callbacks[] = {
 551                 virtio_vsock_rx_done,
 552                 virtio_vsock_tx_done,
 553                 virtio_vsock_event_done,
 554         };
 555         static const char * const names[] = {
 556                 "rx",
 557                 "tx",
 558                 "event",
 559         };
 560         struct virtio_vsock *vsock = NULL;
 561         int ret;
 562
 563         ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
 564         if (ret)
 565                 return ret;
 566
 567         /* Only one virtio-vsock device per guest is supported */
 568         if (the_virtio_vsock) {
 569                 ret = -EBUSY;
 570                 goto out;
 571         }
 572
 573         vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
 574         if (!vsock) {
 575                 ret = -ENOMEM;
 576                 goto out;
 577         }
 578
 579         vsock->vdev = vdev;
 580
 581         ret = virtio_find_vqs(vsock->vdev, VSOCK_VQ_MAX,
 582                               vsock->vqs, callbacks, names,
 583                               NULL);
 584         if (ret < 0)
 585                 goto out;
 586
 587         virtio_vsock_update_guest_cid(vsock);
 588
 589         vsock->rx_buf_nr = 0;
 590         vsock->rx_buf_max_nr = 0;
 591         atomic_set(&vsock->queued_replies, 0);
 592
 593         vdev->priv = vsock;
 594         the_virtio_vsock = vsock;
 595         mutex_init(&vsock->tx_lock);
 596         mutex_init(&vsock->rx_lock);
 597         mutex_init(&vsock->event_lock);
 598         spin_lock_init(&vsock->send_pkt_list_lock);
 599         INIT_LIST_HEAD(&vsock->send_pkt_list);
 600         spin_lock_init(&vsock->loopback_list_lock);
 601         INIT_LIST_HEAD(&vsock->loopback_list);
 602         INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
 603         INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
 604         INIT_WORK(&vsock->event_work, virtio_transport_event_work);
 605         INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
 606         INIT_WORK(&vsock->loopback_work, virtio_transport_loopback_work);
 607
 608         mutex_lock(&vsock->rx_lock);
 609         virtio_vsock_rx_fill(vsock);
 610         mutex_unlock(&vsock->rx_lock);
 611
 612         mutex_lock(&vsock->event_lock);
 613         virtio_vsock_event_fill(vsock);
 614         mutex_unlock(&vsock->event_lock);
 615
 616         mutex_unlock(&the_virtio_vsock_mutex);
 617         return 0;
 618
 619 out:
 620         kfree(vsock);
 621         mutex_unlock(&the_virtio_vsock_mutex);
 622         return ret;
 623 }
 624
 625 static void virtio_vsock_remove(struct virtio_device *vdev)
 626 {
 627         struct virtio_vsock *vsock = vdev->priv;
 628         struct virtio_vsock_pkt *pkt;
 629
 630         flush_work(&vsock->loopback_work);
 631         flush_work(&vsock->rx_work);
 632         flush_work(&vsock->tx_work);
 633         flush_work(&vsock->event_work);
 634         flush_work(&vsock->send_pkt_work);
 635
 636         /* Reset all connected sockets when the device disappear */
 637         vsock_for_each_connected_socket(virtio_vsock_reset_sock);
 638
 639         vdev->config->reset(vdev);
 640
 641         mutex_lock(&vsock->rx_lock);
 642         while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
 643                 virtio_transport_free_pkt(pkt);
 644         mutex_unlock(&vsock->rx_lock);
 645
 646         mutex_lock(&vsock->tx_lock);
 647         while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
 648                 virtio_transport_free_pkt(pkt);
 649         mutex_unlock(&vsock->tx_lock);
 650
 651         spin_lock_bh(&vsock->send_pkt_list_lock);
 652         while (!list_empty(&vsock->send_pkt_list)) {
 653                 pkt = list_first_entry(&vsock->send_pkt_list,
 654                                        struct virtio_vsock_pkt, list);
 655                 list_del(&pkt->list);
 656                 virtio_transport_free_pkt(pkt);
 657         }
 658         spin_unlock_bh(&vsock->send_pkt_list_lock);
 659
 660         spin_lock_bh(&vsock->loopback_list_lock);
 661         while (!list_empty(&vsock->loopback_list)) {
 662                 pkt = list_first_entry(&vsock->loopback_list,
 663                                        struct virtio_vsock_pkt, list);
 664                 list_del(&pkt->list);
 665                 virtio_transport_free_pkt(pkt);
 666         }
 667         spin_unlock_bh(&vsock->loopback_list_lock);
 668
 669         mutex_lock(&the_virtio_vsock_mutex);
 670         the_virtio_vsock = NULL;
 671         mutex_unlock(&the_virtio_vsock_mutex);
 672
 673         vdev->config->del_vqs(vdev);
 674
 675         kfree(vsock);
 676 }
 677
 678 static struct virtio_device_id id_table[] = {
 679         { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
 680         { 0 },
 681 };
 682
 683 static unsigned int features[] = {
 684 };
 685
 686 static struct virtio_driver virtio_vsock_driver = {
 687         .feature_table = features,
 688         .feature_table_size = ARRAY_SIZE(features),
 689         .driver.name = KBUILD_MODNAME,
 690         .driver.owner = THIS_MODULE,
 691         .id_table = id_table,
 692         .probe = virtio_vsock_probe,
 693         .remove = virtio_vsock_remove,
 694 };
 695
 696 static int __init virtio_vsock_init(void)
 697 {
 698         int ret;
 699
 700         virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
 701         if (!virtio_vsock_workqueue)
 702                 return -ENOMEM;
 703
 704         ret = vsock_core_init(&virtio_transport.transport);
 705         if (ret)
 706                 goto out_wq;
 707
 708         ret = register_virtio_driver(&virtio_vsock_driver);
 709         if (ret)
 710                 goto out_vci;
 711
 712         return 0;
 713
 714 out_vci:
 715         vsock_core_exit();
 716 out_wq:
 717         destroy_workqueue(virtio_vsock_workqueue);
 718         return ret;
 719 }
 720
 721 static void __exit virtio_vsock_exit(void)
 722 {
 723         unregister_virtio_driver(&virtio_vsock_driver);
 724         vsock_core_exit();
 725         destroy_workqueue(virtio_vsock_workqueue);
 726 }
 727
 728 module_init(virtio_vsock_init);
 729 module_exit(virtio_vsock_exit);
 730 MODULE_LICENSE("GPL v2");
 731 MODULE_AUTHOR("Asias He");
 732 MODULE_DESCRIPTION("virtio transport for vsock");
 733 MODULE_DEVICE_TABLE(virtio, id_table);