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         struct work_struct loopback_work;
  48         spinlock_t loopback_list_lock; /* protects loopback_list */
  49         struct list_head loopback_list;
  50
  51         atomic_t queued_replies;
  52
  53         /* The following fields are protected by rx_lock.  vqs[VSOCK_VQ_RX]
  54          * must be accessed with rx_lock held.
  55          */
  56         struct mutex rx_lock;
  57         bool rx_run;
  58         int rx_buf_nr;
  59         int rx_buf_max_nr;
  60
  61         /* The following fields are protected by event_lock.
  62          * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
  63          */
  64         struct mutex event_lock;
  65         bool event_run;
  66         struct virtio_vsock_event event_list[8];
  67
  68         u32 guest_cid;
  69 };
  70
  71 static u32 virtio_transport_get_local_cid(void)
  72 {
  73         struct virtio_vsock *vsock;
  74         u32 ret;
  75
  76         rcu_read_lock();
  77         vsock = rcu_dereference(the_virtio_vsock);
  78         if (!vsock) {
  79                 ret = VMADDR_CID_ANY;
  80                 goto out_rcu;
  81         }
  82
  83         ret = vsock->guest_cid;
  84 out_rcu:
  85         rcu_read_unlock();
  86         return ret;
  87 }
  88
  89 static void virtio_transport_loopback_work(struct work_struct *work)
  90 {
  91         struct virtio_vsock *vsock =
  92                 container_of(work, struct virtio_vsock, loopback_work);
  93         LIST_HEAD(pkts);
  94
  95         spin_lock_bh(&vsock->loopback_list_lock);
  96         list_splice_init(&vsock->loopback_list, &pkts);
  97         spin_unlock_bh(&vsock->loopback_list_lock);
  98
  99         mutex_lock(&vsock->rx_lock);
 100
 101         if (!vsock->rx_run)
 102                 goto out;
 103
 104         while (!list_empty(&pkts)) {
 105                 struct virtio_vsock_pkt *pkt;
 106
 107                 pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
 108                 list_del_init(&pkt->list);
 109
 110                 virtio_transport_recv_pkt(pkt);
 111         }
 112 out:
 113         mutex_unlock(&vsock->rx_lock);
 114 }
 115
 116 static int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
 117                                               struct virtio_vsock_pkt *pkt)
 118 {
 119         int len = pkt->len;
 120
 121         spin_lock_bh(&vsock->loopback_list_lock);
 122         list_add_tail(&pkt->list, &vsock->loopback_list);
 123         spin_unlock_bh(&vsock->loopback_list_lock);
 124
 125         queue_work(virtio_vsock_workqueue, &vsock->loopback_work);
 126
 127         return len;
 128 }
 129
 130 static void
 131 virtio_transport_send_pkt_work(struct work_struct *work)
 132 {
 133         struct virtio_vsock *vsock =
 134                 container_of(work, struct virtio_vsock, send_pkt_work);
 135         struct virtqueue *vq;
 136         bool added = false;
 137         bool restart_rx = false;
 138
 139         mutex_lock(&vsock->tx_lock);
 140
 141         if (!vsock->tx_run)
 142                 goto out;
 143
 144         vq = vsock->vqs[VSOCK_VQ_TX];
 145
 146         for (;;) {
 147                 struct virtio_vsock_pkt *pkt;
 148                 struct scatterlist hdr, buf, *sgs[2];
 149                 int ret, in_sg = 0, out_sg = 0;
 150                 bool reply;
 151
 152                 spin_lock_bh(&vsock->send_pkt_list_lock);
 153                 if (list_empty(&vsock->send_pkt_list)) {
 154                         spin_unlock_bh(&vsock->send_pkt_list_lock);
 155                         break;
 156                 }
 157
 158                 pkt = list_first_entry(&vsock->send_pkt_list,
 159                                        struct virtio_vsock_pkt, list);
 160                 list_del_init(&pkt->list);
 161                 spin_unlock_bh(&vsock->send_pkt_list_lock);
 162
 163                 virtio_transport_deliver_tap_pkt(pkt);
 164
 165                 reply = pkt->reply;
 166
 167                 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
 168                 sgs[out_sg++] = &hdr;
 169                 if (pkt->buf) {
 170                         sg_init_one(&buf, pkt->buf, pkt->len);
 171                         sgs[out_sg++] = &buf;
 172                 }
 173
 174                 ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
 175                 /* Usually this means that there is no more space available in
 176                  * the vq
 177                  */
 178                 if (ret < 0) {
 179                         spin_lock_bh(&vsock->send_pkt_list_lock);
 180                         list_add(&pkt->list, &vsock->send_pkt_list);
 181                         spin_unlock_bh(&vsock->send_pkt_list_lock);
 182                         break;
 183                 }
 184
 185                 if (reply) {
 186                         struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 187                         int val;
 188
 189                         val = atomic_dec_return(&vsock->queued_replies);
 190
 191                         /* Do we now have resources to resume rx processing? */
 192                         if (val + 1 == virtqueue_get_vring_size(rx_vq))
 193                                 restart_rx = true;
 194                 }
 195
 196                 added = true;
 197         }
 198
 199         if (added)
 200                 virtqueue_kick(vq);
 201
 202 out:
 203         mutex_unlock(&vsock->tx_lock);
 204
 205         if (restart_rx)
 206                 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 207 }
 208
 209 static int
 210 virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
 211 {
 212         struct virtio_vsock *vsock;
 213         int len = pkt->len;
 214
 215         rcu_read_lock();
 216         vsock = rcu_dereference(the_virtio_vsock);
 217         if (!vsock) {
 218                 virtio_transport_free_pkt(pkt);
 219                 len = -ENODEV;
 220                 goto out_rcu;
 221         }
 222
 223         if (le64_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid) {
 224                 len = virtio_transport_send_pkt_loopback(vsock, pkt);
 225                 goto out_rcu;
 226         }
 227
 228         if (pkt->reply)
 229                 atomic_inc(&vsock->queued_replies);
 230
 231         spin_lock_bh(&vsock->send_pkt_list_lock);
 232         list_add_tail(&pkt->list, &vsock->send_pkt_list);
 233         spin_unlock_bh(&vsock->send_pkt_list_lock);
 234
 235         queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 236
 237 out_rcu:
 238         rcu_read_unlock();
 239         return len;
 240 }
 241
 242 static int
 243 virtio_transport_cancel_pkt(struct vsock_sock *vsk)
 244 {
 245         struct virtio_vsock *vsock;
 246         struct virtio_vsock_pkt *pkt, *n;
 247         int cnt = 0, ret;
 248         LIST_HEAD(freeme);
 249
 250         rcu_read_lock();
 251         vsock = rcu_dereference(the_virtio_vsock);
 252         if (!vsock) {
 253                 ret = -ENODEV;
 254                 goto out_rcu;
 255         }
 256
 257         spin_lock_bh(&vsock->send_pkt_list_lock);
 258         list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
 259                 if (pkt->vsk != vsk)
 260                         continue;
 261                 list_move(&pkt->list, &freeme);
 262         }
 263         spin_unlock_bh(&vsock->send_pkt_list_lock);
 264
 265         list_for_each_entry_safe(pkt, n, &freeme, list) {
 266                 if (pkt->reply)
 267                         cnt++;
 268                 list_del(&pkt->list);
 269                 virtio_transport_free_pkt(pkt);
 270         }
 271
 272         if (cnt) {
 273                 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 274                 int new_cnt;
 275
 276                 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
 277                 if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
 278                     new_cnt < virtqueue_get_vring_size(rx_vq))
 279                         queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 280         }
 281
 282         ret = 0;
 283
 284 out_rcu:
 285         rcu_read_unlock();
 286         return ret;
 287 }
 288
 289 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
 290 {
 291         int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
 292         struct virtio_vsock_pkt *pkt;
 293         struct scatterlist hdr, buf, *sgs[2];
 294         struct virtqueue *vq;
 295         int ret;
 296
 297         vq = vsock->vqs[VSOCK_VQ_RX];
 298
 299         do {
 300                 pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 301                 if (!pkt)
 302                         break;
 303
 304                 pkt->buf = kmalloc(buf_len, GFP_KERNEL);
 305                 if (!pkt->buf) {
 306                         virtio_transport_free_pkt(pkt);
 307                         break;
 308                 }
 309
 310                 pkt->buf_len = buf_len;
 311                 pkt->len = buf_len;
 312
 313                 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
 314                 sgs[0] = &hdr;
 315
 316                 sg_init_one(&buf, pkt->buf, buf_len);
 317                 sgs[1] = &buf;
 318                 ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
 319                 if (ret) {
 320                         virtio_transport_free_pkt(pkt);
 321                         break;
 322                 }
 323                 vsock->rx_buf_nr++;
 324         } while (vq->num_free);
 325         if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
 326                 vsock->rx_buf_max_nr = vsock->rx_buf_nr;
 327         virtqueue_kick(vq);
 328 }
 329
 330 static void virtio_transport_tx_work(struct work_struct *work)
 331 {
 332         struct virtio_vsock *vsock =
 333                 container_of(work, struct virtio_vsock, tx_work);
 334         struct virtqueue *vq;
 335         bool added = false;
 336
 337         vq = vsock->vqs[VSOCK_VQ_TX];
 338         mutex_lock(&vsock->tx_lock);
 339
 340         if (!vsock->tx_run)
 341                 goto out;
 342
 343         do {
 344                 struct virtio_vsock_pkt *pkt;
 345                 unsigned int len;
 346
 347                 virtqueue_disable_cb(vq);
 348                 while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
 349                         virtio_transport_free_pkt(pkt);
 350                         added = true;
 351                 }
 352         } while (!virtqueue_enable_cb(vq));
 353
 354 out:
 355         mutex_unlock(&vsock->tx_lock);
 356
 357         if (added)
 358                 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 359 }
 360
 361 /* Is there space left for replies to rx packets? */
 362 static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
 363 {
 364         struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
 365         int val;
 366
 367         smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
 368         val = atomic_read(&vsock->queued_replies);
 369
 370         return val < virtqueue_get_vring_size(vq);
 371 }
 372
 373 static void virtio_transport_rx_work(struct work_struct *work)
 374 {
 375         struct virtio_vsock *vsock =
 376                 container_of(work, struct virtio_vsock, rx_work);
 377         struct virtqueue *vq;
 378
 379         vq = vsock->vqs[VSOCK_VQ_RX];
 380
 381         mutex_lock(&vsock->rx_lock);
 382
 383         if (!vsock->rx_run)
 384                 goto out;
 385
 386         do {
 387                 virtqueue_disable_cb(vq);
 388                 for (;;) {
 389                         struct virtio_vsock_pkt *pkt;
 390                         unsigned int len;
 391
 392                         if (!virtio_transport_more_replies(vsock)) {
 393                                 /* Stop rx until the device processes already
 394                                  * pending replies.  Leave rx virtqueue
 395                                  * callbacks disabled.
 396                                  */
 397                                 goto out;
 398                         }
 399
 400                         pkt = virtqueue_get_buf(vq, &len);
 401                         if (!pkt) {
 402                                 break;
 403                         }
 404
 405                         vsock->rx_buf_nr--;
 406
 407                         /* Drop short/long packets */
 408                         if (unlikely(len < sizeof(pkt->hdr) ||
 409                                      len > sizeof(pkt->hdr) + pkt->len)) {
 410                                 virtio_transport_free_pkt(pkt);
 411                                 continue;
 412                         }
 413
 414                         pkt->len = len - sizeof(pkt->hdr);
 415                         virtio_transport_deliver_tap_pkt(pkt);
 416                         virtio_transport_recv_pkt(pkt);
 417                 }
 418         } while (!virtqueue_enable_cb(vq));
 419
 420 out:
 421         if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
 422                 virtio_vsock_rx_fill(vsock);
 423         mutex_unlock(&vsock->rx_lock);
 424 }
 425
 426 /* event_lock must be held */
 427 static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
 428                                        struct virtio_vsock_event *event)
 429 {
 430         struct scatterlist sg;
 431         struct virtqueue *vq;
 432
 433         vq = vsock->vqs[VSOCK_VQ_EVENT];
 434
 435         sg_init_one(&sg, event, sizeof(*event));
 436
 437         return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
 438 }
 439
 440 /* event_lock must be held */
 441 static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
 442 {
 443         size_t i;
 444
 445         for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
 446                 struct virtio_vsock_event *event = &vsock->event_list[i];
 447
 448                 virtio_vsock_event_fill_one(vsock, event);
 449         }
 450
 451         virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
 452 }
 453
 454 static void virtio_vsock_reset_sock(struct sock *sk)
 455 {
 456         lock_sock(sk);
 457         sk->sk_state = TCP_CLOSE;
 458         sk->sk_err = ECONNRESET;
 459         sk->sk_error_report(sk);
 460         release_sock(sk);
 461 }
 462
 463 static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
 464 {
 465         struct virtio_device *vdev = vsock->vdev;
 466         __le64 guest_cid;
 467
 468         vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
 469                           &guest_cid, sizeof(guest_cid));
 470         vsock->guest_cid = le64_to_cpu(guest_cid);
 471 }
 472
 473 /* event_lock must be held */
 474 static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
 475                                       struct virtio_vsock_event *event)
 476 {
 477         switch (le32_to_cpu(event->id)) {
 478         case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
 479                 virtio_vsock_update_guest_cid(vsock);
 480                 vsock_for_each_connected_socket(virtio_vsock_reset_sock);
 481                 break;
 482         }
 483 }
 484
 485 static void virtio_transport_event_work(struct work_struct *work)
 486 {
 487         struct virtio_vsock *vsock =
 488                 container_of(work, struct virtio_vsock, event_work);
 489         struct virtqueue *vq;
 490
 491         vq = vsock->vqs[VSOCK_VQ_EVENT];
 492
 493         mutex_lock(&vsock->event_lock);
 494
 495         if (!vsock->event_run)
 496                 goto out;
 497
 498         do {
 499                 struct virtio_vsock_event *event;
 500                 unsigned int len;
 501
 502                 virtqueue_disable_cb(vq);
 503                 while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
 504                         if (len == sizeof(*event))
 505                                 virtio_vsock_event_handle(vsock, event);
 506
 507                         virtio_vsock_event_fill_one(vsock, event);
 508                 }
 509         } while (!virtqueue_enable_cb(vq));
 510
 511         virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
 512 out:
 513         mutex_unlock(&vsock->event_lock);
 514 }
 515
 516 static void virtio_vsock_event_done(struct virtqueue *vq)
 517 {
 518         struct virtio_vsock *vsock = vq->vdev->priv;
 519
 520         if (!vsock)
 521                 return;
 522         queue_work(virtio_vsock_workqueue, &vsock->event_work);
 523 }
 524
 525 static void virtio_vsock_tx_done(struct virtqueue *vq)
 526 {
 527         struct virtio_vsock *vsock = vq->vdev->priv;
 528
 529         if (!vsock)
 530                 return;
 531         queue_work(virtio_vsock_workqueue, &vsock->tx_work);
 532 }
 533
 534 static void virtio_vsock_rx_done(struct virtqueue *vq)
 535 {
 536         struct virtio_vsock *vsock = vq->vdev->priv;
 537
 538         if (!vsock)
 539                 return;
 540         queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 541 }
 542
 543 static struct virtio_transport virtio_transport = {
 544         .transport = {
 545                 .get_local_cid            = virtio_transport_get_local_cid,
 546
 547                 .init                     = virtio_transport_do_socket_init,
 548                 .destruct                 = virtio_transport_destruct,
 549                 .release                  = virtio_transport_release,
 550                 .connect                  = virtio_transport_connect,
 551                 .shutdown                 = virtio_transport_shutdown,
 552                 .cancel_pkt               = virtio_transport_cancel_pkt,
 553
 554                 .dgram_bind               = virtio_transport_dgram_bind,
 555                 .dgram_dequeue            = virtio_transport_dgram_dequeue,
 556                 .dgram_enqueue            = virtio_transport_dgram_enqueue,
 557                 .dgram_allow              = virtio_transport_dgram_allow,
 558
 559                 .stream_dequeue           = virtio_transport_stream_dequeue,
 560                 .stream_enqueue           = virtio_transport_stream_enqueue,
 561                 .stream_has_data          = virtio_transport_stream_has_data,
 562                 .stream_has_space         = virtio_transport_stream_has_space,
 563                 .stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
 564                 .stream_is_active         = virtio_transport_stream_is_active,
 565                 .stream_allow             = virtio_transport_stream_allow,
 566
 567                 .notify_poll_in           = virtio_transport_notify_poll_in,
 568                 .notify_poll_out          = virtio_transport_notify_poll_out,
 569                 .notify_recv_init         = virtio_transport_notify_recv_init,
 570                 .notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
 571                 .notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
 572                 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
 573                 .notify_send_init         = virtio_transport_notify_send_init,
 574                 .notify_send_pre_block    = virtio_transport_notify_send_pre_block,
 575                 .notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
 576                 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
 577
 578                 .set_buffer_size          = virtio_transport_set_buffer_size,
 579                 .set_min_buffer_size      = virtio_transport_set_min_buffer_size,
 580                 .set_max_buffer_size      = virtio_transport_set_max_buffer_size,
 581                 .get_buffer_size          = virtio_transport_get_buffer_size,
 582                 .get_min_buffer_size      = virtio_transport_get_min_buffer_size,
 583                 .get_max_buffer_size      = virtio_transport_get_max_buffer_size,
 584         },
 585
 586         .send_pkt = virtio_transport_send_pkt,
 587 };
 588
 589 static int virtio_vsock_probe(struct virtio_device *vdev)
 590 {
 591         vq_callback_t *callbacks[] = {
 592                 virtio_vsock_rx_done,
 593                 virtio_vsock_tx_done,
 594                 virtio_vsock_event_done,
 595         };
 596         static const char * const names[] = {
 597                 "rx",
 598                 "tx",
 599                 "event",
 600         };
 601         struct virtio_vsock *vsock = NULL;
 602         int ret;
 603
 604         ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
 605         if (ret)
 606                 return ret;
 607
 608         /* Only one virtio-vsock device per guest is supported */
 609         if (rcu_dereference_protected(the_virtio_vsock,
 610                                 lockdep_is_held(&the_virtio_vsock_mutex))) {
 611                 ret = -EBUSY;
 612                 goto out;
 613         }
 614
 615         vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
 616         if (!vsock) {
 617                 ret = -ENOMEM;
 618                 goto out;
 619         }
 620
 621         vsock->vdev = vdev;
 622
 623         ret = virtio_find_vqs(vsock->vdev, VSOCK_VQ_MAX,
 624                               vsock->vqs, callbacks, names,
 625                               NULL);
 626         if (ret < 0)
 627                 goto out;
 628
 629         virtio_vsock_update_guest_cid(vsock);
 630
 631         vsock->rx_buf_nr = 0;
 632         vsock->rx_buf_max_nr = 0;
 633         atomic_set(&vsock->queued_replies, 0);
 634
 635         mutex_init(&vsock->tx_lock);
 636         mutex_init(&vsock->rx_lock);
 637         mutex_init(&vsock->event_lock);
 638         spin_lock_init(&vsock->send_pkt_list_lock);
 639         INIT_LIST_HEAD(&vsock->send_pkt_list);
 640         spin_lock_init(&vsock->loopback_list_lock);
 641         INIT_LIST_HEAD(&vsock->loopback_list);
 642         INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
 643         INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
 644         INIT_WORK(&vsock->event_work, virtio_transport_event_work);
 645         INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
 646         INIT_WORK(&vsock->loopback_work, virtio_transport_loopback_work);
 647
 648         mutex_lock(&vsock->tx_lock);
 649         vsock->tx_run = true;
 650         mutex_unlock(&vsock->tx_lock);
 651
 652         mutex_lock(&vsock->rx_lock);
 653         virtio_vsock_rx_fill(vsock);
 654         vsock->rx_run = true;
 655         mutex_unlock(&vsock->rx_lock);
 656
 657         mutex_lock(&vsock->event_lock);
 658         virtio_vsock_event_fill(vsock);
 659         vsock->event_run = true;
 660         mutex_unlock(&vsock->event_lock);
 661
 662         vdev->priv = vsock;
 663         rcu_assign_pointer(the_virtio_vsock, vsock);
 664
 665         mutex_unlock(&the_virtio_vsock_mutex);
 666         return 0;
 667
 668 out:
 669         kfree(vsock);
 670         mutex_unlock(&the_virtio_vsock_mutex);
 671         return ret;
 672 }
 673
 674 static void virtio_vsock_remove(struct virtio_device *vdev)
 675 {
 676         struct virtio_vsock *vsock = vdev->priv;
 677         struct virtio_vsock_pkt *pkt;
 678
 679         mutex_lock(&the_virtio_vsock_mutex);
 680
 681         vdev->priv = NULL;
 682         rcu_assign_pointer(the_virtio_vsock, NULL);
 683         synchronize_rcu();
 684
 685         /* Reset all connected sockets when the device disappear */
 686         vsock_for_each_connected_socket(virtio_vsock_reset_sock);
 687
 688         /* Stop all work handlers to make sure no one is accessing the device,
 689          * so we can safely call vdev->config->reset().
 690          */
 691         mutex_lock(&vsock->rx_lock);
 692         vsock->rx_run = false;
 693         mutex_unlock(&vsock->rx_lock);
 694
 695         mutex_lock(&vsock->tx_lock);
 696         vsock->tx_run = false;
 697         mutex_unlock(&vsock->tx_lock);
 698
 699         mutex_lock(&vsock->event_lock);
 700         vsock->event_run = false;
 701         mutex_unlock(&vsock->event_lock);
 702
 703         /* Flush all device writes and interrupts, device will not use any
 704          * more buffers.
 705          */
 706         vdev->config->reset(vdev);
 707
 708         mutex_lock(&vsock->rx_lock);
 709         while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
 710                 virtio_transport_free_pkt(pkt);
 711         mutex_unlock(&vsock->rx_lock);
 712
 713         mutex_lock(&vsock->tx_lock);
 714         while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
 715                 virtio_transport_free_pkt(pkt);
 716         mutex_unlock(&vsock->tx_lock);
 717
 718         spin_lock_bh(&vsock->send_pkt_list_lock);
 719         while (!list_empty(&vsock->send_pkt_list)) {
 720                 pkt = list_first_entry(&vsock->send_pkt_list,
 721                                        struct virtio_vsock_pkt, list);
 722                 list_del(&pkt->list);
 723                 virtio_transport_free_pkt(pkt);
 724         }
 725         spin_unlock_bh(&vsock->send_pkt_list_lock);
 726
 727         spin_lock_bh(&vsock->loopback_list_lock);
 728         while (!list_empty(&vsock->loopback_list)) {
 729                 pkt = list_first_entry(&vsock->loopback_list,
 730                                        struct virtio_vsock_pkt, list);
 731                 list_del(&pkt->list);
 732                 virtio_transport_free_pkt(pkt);
 733         }
 734         spin_unlock_bh(&vsock->loopback_list_lock);
 735
 736         /* Delete virtqueues and flush outstanding callbacks if any */
 737         vdev->config->del_vqs(vdev);
 738
 739         /* Other works can be queued before 'config->del_vqs()', so we flush
 740          * all works before to free the vsock object to avoid use after free.
 741          */
 742         flush_work(&vsock->loopback_work);
 743         flush_work(&vsock->rx_work);
 744         flush_work(&vsock->tx_work);
 745         flush_work(&vsock->event_work);
 746         flush_work(&vsock->send_pkt_work);
 747
 748         mutex_unlock(&the_virtio_vsock_mutex);
 749
 750         kfree(vsock);
 751 }
 752
 753 static struct virtio_device_id id_table[] = {
 754         { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
 755         { 0 },
 756 };
 757
 758 static unsigned int features[] = {
 759 };
 760
 761 static struct virtio_driver virtio_vsock_driver = {
 762         .feature_table = features,
 763         .feature_table_size = ARRAY_SIZE(features),
 764         .driver.name = KBUILD_MODNAME,
 765         .driver.owner = THIS_MODULE,
 766         .id_table = id_table,
 767         .probe = virtio_vsock_probe,
 768         .remove = virtio_vsock_remove,
 769 };
 770
 771 static int __init virtio_vsock_init(void)
 772 {
 773         int ret;
 774
 775         virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
 776         if (!virtio_vsock_workqueue)
 777                 return -ENOMEM;
 778
 779         ret = vsock_core_init(&virtio_transport.transport);
 780         if (ret)
 781                 goto out_wq;
 782
 783         ret = register_virtio_driver(&virtio_vsock_driver);
 784         if (ret)
 785                 goto out_vci;
 786
 787         return 0;
 788
 789 out_vci:
 790         vsock_core_exit();
 791 out_wq:
 792         destroy_workqueue(virtio_vsock_workqueue);
 793         return ret;
 794 }
 795
 796 static void __exit virtio_vsock_exit(void)
 797 {
 798         unregister_virtio_driver(&virtio_vsock_driver);
 799         vsock_core_exit();
 800         destroy_workqueue(virtio_vsock_workqueue);
 801 }
 802
 803 module_init(virtio_vsock_init);
 804 module_exit(virtio_vsock_exit);
 805 MODULE_LICENSE("GPL v2");
 806 MODULE_AUTHOR("Asias He");
 807 MODULE_DESCRIPTION("virtio transport for vsock");
 808 MODULE_DEVICE_TABLE(virtio, id_table);