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         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 int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
  90                                               struct virtio_vsock_pkt *pkt)
  91 {
  92         int len = pkt->len;
  93
  94         spin_lock_bh(&vsock->loopback_list_lock);
  95         list_add_tail(&pkt->list, &vsock->loopback_list);
  96         spin_unlock_bh(&vsock->loopback_list_lock);
  97
  98         queue_work(virtio_vsock_workqueue, &vsock->loopback_work);
  99
 100         return len;
 101 }
 102
 103 static void
 104 virtio_transport_send_pkt_work(struct work_struct *work)
 105 {
 106         struct virtio_vsock *vsock =
 107                 container_of(work, struct virtio_vsock, send_pkt_work);
 108         struct virtqueue *vq;
 109         bool added = false;
 110         bool restart_rx = false;
 111
 112         mutex_lock(&vsock->tx_lock);
 113
 114         if (!vsock->tx_run)
 115                 goto out;
 116
 117         vq = vsock->vqs[VSOCK_VQ_TX];
 118
 119         for (;;) {
 120                 struct virtio_vsock_pkt *pkt;
 121                 struct scatterlist hdr, buf, *sgs[2];
 122                 int ret, in_sg = 0, out_sg = 0;
 123                 bool reply;
 124
 125                 spin_lock_bh(&vsock->send_pkt_list_lock);
 126                 if (list_empty(&vsock->send_pkt_list)) {
 127                         spin_unlock_bh(&vsock->send_pkt_list_lock);
 128                         break;
 129                 }
 130
 131                 pkt = list_first_entry(&vsock->send_pkt_list,
 132                                        struct virtio_vsock_pkt, list);
 133                 list_del_init(&pkt->list);
 134                 spin_unlock_bh(&vsock->send_pkt_list_lock);
 135
 136                 virtio_transport_deliver_tap_pkt(pkt);
 137
 138                 reply = pkt->reply;
 139
 140                 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
 141                 sgs[out_sg++] = &hdr;
 142                 if (pkt->buf) {
 143                         sg_init_one(&buf, pkt->buf, pkt->len);
 144                         sgs[out_sg++] = &buf;
 145                 }
 146
 147                 ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
 148                 /* Usually this means that there is no more space available in
 149                  * the vq
 150                  */
 151                 if (ret < 0) {
 152                         spin_lock_bh(&vsock->send_pkt_list_lock);
 153                         list_add(&pkt->list, &vsock->send_pkt_list);
 154                         spin_unlock_bh(&vsock->send_pkt_list_lock);
 155                         break;
 156                 }
 157
 158                 if (reply) {
 159                         struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 160                         int val;
 161
 162                         val = atomic_dec_return(&vsock->queued_replies);
 163
 164                         /* Do we now have resources to resume rx processing? */
 165                         if (val + 1 == virtqueue_get_vring_size(rx_vq))
 166                                 restart_rx = true;
 167                 }
 168
 169                 added = true;
 170         }
 171
 172         if (added)
 173                 virtqueue_kick(vq);
 174
 175 out:
 176         mutex_unlock(&vsock->tx_lock);
 177
 178         if (restart_rx)
 179                 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 180 }
 181
 182 static int
 183 virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
 184 {
 185         struct virtio_vsock *vsock;
 186         int len = pkt->len;
 187
 188         rcu_read_lock();
 189         vsock = rcu_dereference(the_virtio_vsock);
 190         if (!vsock) {
 191                 virtio_transport_free_pkt(pkt);
 192                 len = -ENODEV;
 193                 goto out_rcu;
 194         }
 195
 196         if (le64_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid) {
 197                 len = virtio_transport_send_pkt_loopback(vsock, pkt);
 198                 goto out_rcu;
 199         }
 200
 201         if (pkt->reply)
 202                 atomic_inc(&vsock->queued_replies);
 203
 204         spin_lock_bh(&vsock->send_pkt_list_lock);
 205         list_add_tail(&pkt->list, &vsock->send_pkt_list);
 206         spin_unlock_bh(&vsock->send_pkt_list_lock);
 207
 208         queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 209
 210 out_rcu:
 211         rcu_read_unlock();
 212         return len;
 213 }
 214
 215 static int
 216 virtio_transport_cancel_pkt(struct vsock_sock *vsk)
 217 {
 218         struct virtio_vsock *vsock;
 219         struct virtio_vsock_pkt *pkt, *n;
 220         int cnt = 0, ret;
 221         LIST_HEAD(freeme);
 222
 223         rcu_read_lock();
 224         vsock = rcu_dereference(the_virtio_vsock);
 225         if (!vsock) {
 226                 ret = -ENODEV;
 227                 goto out_rcu;
 228         }
 229
 230         spin_lock_bh(&vsock->send_pkt_list_lock);
 231         list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
 232                 if (pkt->vsk != vsk)
 233                         continue;
 234                 list_move(&pkt->list, &freeme);
 235         }
 236         spin_unlock_bh(&vsock->send_pkt_list_lock);
 237
 238         list_for_each_entry_safe(pkt, n, &freeme, list) {
 239                 if (pkt->reply)
 240                         cnt++;
 241                 list_del(&pkt->list);
 242                 virtio_transport_free_pkt(pkt);
 243         }
 244
 245         if (cnt) {
 246                 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 247                 int new_cnt;
 248
 249                 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
 250                 if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
 251                     new_cnt < virtqueue_get_vring_size(rx_vq))
 252                         queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 253         }
 254
 255         ret = 0;
 256
 257 out_rcu:
 258         rcu_read_unlock();
 259         return ret;
 260 }
 261
 262 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
 263 {
 264         int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
 265         struct virtio_vsock_pkt *pkt;
 266         struct scatterlist hdr, buf, *sgs[2];
 267         struct virtqueue *vq;
 268         int ret;
 269
 270         vq = vsock->vqs[VSOCK_VQ_RX];
 271
 272         do {
 273                 pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 274                 if (!pkt)
 275                         break;
 276
 277                 pkt->buf = kmalloc(buf_len, GFP_KERNEL);
 278                 if (!pkt->buf) {
 279                         virtio_transport_free_pkt(pkt);
 280                         break;
 281                 }
 282
 283                 pkt->buf_len = buf_len;
 284                 pkt->len = buf_len;
 285
 286                 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
 287                 sgs[0] = &hdr;
 288
 289                 sg_init_one(&buf, pkt->buf, buf_len);
 290                 sgs[1] = &buf;
 291                 ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
 292                 if (ret) {
 293                         virtio_transport_free_pkt(pkt);
 294                         break;
 295                 }
 296                 vsock->rx_buf_nr++;
 297         } while (vq->num_free);
 298         if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
 299                 vsock->rx_buf_max_nr = vsock->rx_buf_nr;
 300         virtqueue_kick(vq);
 301 }
 302
 303 static void virtio_transport_tx_work(struct work_struct *work)
 304 {
 305         struct virtio_vsock *vsock =
 306                 container_of(work, struct virtio_vsock, tx_work);
 307         struct virtqueue *vq;
 308         bool added = false;
 309
 310         vq = vsock->vqs[VSOCK_VQ_TX];
 311         mutex_lock(&vsock->tx_lock);
 312
 313         if (!vsock->tx_run)
 314                 goto out;
 315
 316         do {
 317                 struct virtio_vsock_pkt *pkt;
 318                 unsigned int len;
 319
 320                 virtqueue_disable_cb(vq);
 321                 while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
 322                         virtio_transport_free_pkt(pkt);
 323                         added = true;
 324                 }
 325         } while (!virtqueue_enable_cb(vq));
 326
 327 out:
 328         mutex_unlock(&vsock->tx_lock);
 329
 330         if (added)
 331                 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 332 }
 333
 334 /* Is there space left for replies to rx packets? */
 335 static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
 336 {
 337         struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
 338         int val;
 339
 340         smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
 341         val = atomic_read(&vsock->queued_replies);
 342
 343         return val < virtqueue_get_vring_size(vq);
 344 }
 345
 346 /* event_lock must be held */
 347 static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
 348                                        struct virtio_vsock_event *event)
 349 {
 350         struct scatterlist sg;
 351         struct virtqueue *vq;
 352
 353         vq = vsock->vqs[VSOCK_VQ_EVENT];
 354
 355         sg_init_one(&sg, event, sizeof(*event));
 356
 357         return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
 358 }
 359
 360 /* event_lock must be held */
 361 static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
 362 {
 363         size_t i;
 364
 365         for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
 366                 struct virtio_vsock_event *event = &vsock->event_list[i];
 367
 368                 virtio_vsock_event_fill_one(vsock, event);
 369         }
 370
 371         virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
 372 }
 373
 374 static void virtio_vsock_reset_sock(struct sock *sk)
 375 {
 376         lock_sock(sk);
 377         sk->sk_state = TCP_CLOSE;
 378         sk->sk_err = ECONNRESET;
 379         sk->sk_error_report(sk);
 380         release_sock(sk);
 381 }
 382
 383 static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
 384 {
 385         struct virtio_device *vdev = vsock->vdev;
 386         __le64 guest_cid;
 387
 388         vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
 389                           &guest_cid, sizeof(guest_cid));
 390         vsock->guest_cid = le64_to_cpu(guest_cid);
 391 }
 392
 393 /* event_lock must be held */
 394 static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
 395                                       struct virtio_vsock_event *event)
 396 {
 397         switch (le32_to_cpu(event->id)) {
 398         case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
 399                 virtio_vsock_update_guest_cid(vsock);
 400                 vsock_for_each_connected_socket(virtio_vsock_reset_sock);
 401                 break;
 402         }
 403 }
 404
 405 static void virtio_transport_event_work(struct work_struct *work)
 406 {
 407         struct virtio_vsock *vsock =
 408                 container_of(work, struct virtio_vsock, event_work);
 409         struct virtqueue *vq;
 410
 411         vq = vsock->vqs[VSOCK_VQ_EVENT];
 412
 413         mutex_lock(&vsock->event_lock);
 414
 415         if (!vsock->event_run)
 416                 goto out;
 417
 418         do {
 419                 struct virtio_vsock_event *event;
 420                 unsigned int len;
 421
 422                 virtqueue_disable_cb(vq);
 423                 while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
 424                         if (len == sizeof(*event))
 425                                 virtio_vsock_event_handle(vsock, event);
 426
 427                         virtio_vsock_event_fill_one(vsock, event);
 428                 }
 429         } while (!virtqueue_enable_cb(vq));
 430
 431         virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
 432 out:
 433         mutex_unlock(&vsock->event_lock);
 434 }
 435
 436 static void virtio_vsock_event_done(struct virtqueue *vq)
 437 {
 438         struct virtio_vsock *vsock = vq->vdev->priv;
 439
 440         if (!vsock)
 441                 return;
 442         queue_work(virtio_vsock_workqueue, &vsock->event_work);
 443 }
 444
 445 static void virtio_vsock_tx_done(struct virtqueue *vq)
 446 {
 447         struct virtio_vsock *vsock = vq->vdev->priv;
 448
 449         if (!vsock)
 450                 return;
 451         queue_work(virtio_vsock_workqueue, &vsock->tx_work);
 452 }
 453
 454 static void virtio_vsock_rx_done(struct virtqueue *vq)
 455 {
 456         struct virtio_vsock *vsock = vq->vdev->priv;
 457
 458         if (!vsock)
 459                 return;
 460         queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 461 }
 462
 463 static struct virtio_transport virtio_transport = {
 464         .transport = {
 465                 .module                   = THIS_MODULE,
 466
 467                 .get_local_cid            = virtio_transport_get_local_cid,
 468
 469                 .init                     = virtio_transport_do_socket_init,
 470                 .destruct                 = virtio_transport_destruct,
 471                 .release                  = virtio_transport_release,
 472                 .connect                  = virtio_transport_connect,
 473                 .shutdown                 = virtio_transport_shutdown,
 474                 .cancel_pkt               = virtio_transport_cancel_pkt,
 475
 476                 .dgram_bind               = virtio_transport_dgram_bind,
 477                 .dgram_dequeue            = virtio_transport_dgram_dequeue,
 478                 .dgram_enqueue            = virtio_transport_dgram_enqueue,
 479                 .dgram_allow              = virtio_transport_dgram_allow,
 480
 481                 .stream_dequeue           = virtio_transport_stream_dequeue,
 482                 .stream_enqueue           = virtio_transport_stream_enqueue,
 483                 .stream_has_data          = virtio_transport_stream_has_data,
 484                 .stream_has_space         = virtio_transport_stream_has_space,
 485                 .stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
 486                 .stream_is_active         = virtio_transport_stream_is_active,
 487                 .stream_allow             = virtio_transport_stream_allow,
 488
 489                 .notify_poll_in           = virtio_transport_notify_poll_in,
 490                 .notify_poll_out          = virtio_transport_notify_poll_out,
 491                 .notify_recv_init         = virtio_transport_notify_recv_init,
 492                 .notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
 493                 .notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
 494                 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
 495                 .notify_send_init         = virtio_transport_notify_send_init,
 496                 .notify_send_pre_block    = virtio_transport_notify_send_pre_block,
 497                 .notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
 498                 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
 499                 .notify_buffer_size       = virtio_transport_notify_buffer_size,
 500         },
 501
 502         .send_pkt = virtio_transport_send_pkt,
 503 };
 504
 505 static void virtio_transport_loopback_work(struct work_struct *work)
 506 {
 507         struct virtio_vsock *vsock =
 508                 container_of(work, struct virtio_vsock, loopback_work);
 509         LIST_HEAD(pkts);
 510
 511         spin_lock_bh(&vsock->loopback_list_lock);
 512         list_splice_init(&vsock->loopback_list, &pkts);
 513         spin_unlock_bh(&vsock->loopback_list_lock);
 514
 515         mutex_lock(&vsock->rx_lock);
 516
 517         if (!vsock->rx_run)
 518                 goto out;
 519
 520         while (!list_empty(&pkts)) {
 521                 struct virtio_vsock_pkt *pkt;
 522
 523                 pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
 524                 list_del_init(&pkt->list);
 525
 526                 virtio_transport_recv_pkt(&virtio_transport, pkt);
 527         }
 528 out:
 529         mutex_unlock(&vsock->rx_lock);
 530 }
 531
 532 static void virtio_transport_rx_work(struct work_struct *work)
 533 {
 534         struct virtio_vsock *vsock =
 535                 container_of(work, struct virtio_vsock, rx_work);
 536         struct virtqueue *vq;
 537
 538         vq = vsock->vqs[VSOCK_VQ_RX];
 539
 540         mutex_lock(&vsock->rx_lock);
 541
 542         if (!vsock->rx_run)
 543                 goto out;
 544
 545         do {
 546                 virtqueue_disable_cb(vq);
 547                 for (;;) {
 548                         struct virtio_vsock_pkt *pkt;
 549                         unsigned int len;
 550
 551                         if (!virtio_transport_more_replies(vsock)) {
 552                                 /* Stop rx until the device processes already
 553                                  * pending replies.  Leave rx virtqueue
 554                                  * callbacks disabled.
 555                                  */
 556                                 goto out;
 557                         }
 558
 559                         pkt = virtqueue_get_buf(vq, &len);
 560                         if (!pkt) {
 561                                 break;
 562                         }
 563
 564                         vsock->rx_buf_nr--;
 565
 566                         /* Drop short/long packets */
 567                         if (unlikely(len < sizeof(pkt->hdr) ||
 568                                      len > sizeof(pkt->hdr) + pkt->len)) {
 569                                 virtio_transport_free_pkt(pkt);
 570                                 continue;
 571                         }
 572
 573                         pkt->len = len - sizeof(pkt->hdr);
 574                         virtio_transport_deliver_tap_pkt(pkt);
 575                         virtio_transport_recv_pkt(&virtio_transport, pkt);
 576                 }
 577         } while (!virtqueue_enable_cb(vq));
 578
 579 out:
 580         if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
 581                 virtio_vsock_rx_fill(vsock);
 582         mutex_unlock(&vsock->rx_lock);
 583 }
 584
 585 static int virtio_vsock_probe(struct virtio_device *vdev)
 586 {
 587         vq_callback_t *callbacks[] = {
 588                 virtio_vsock_rx_done,
 589                 virtio_vsock_tx_done,
 590                 virtio_vsock_event_done,
 591         };
 592         static const char * const names[] = {
 593                 "rx",
 594                 "tx",
 595                 "event",
 596         };
 597         struct virtio_vsock *vsock = NULL;
 598         int ret;
 599
 600         ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
 601         if (ret)
 602                 return ret;
 603
 604         /* Only one virtio-vsock device per guest is supported */
 605         if (rcu_dereference_protected(the_virtio_vsock,
 606                                 lockdep_is_held(&the_virtio_vsock_mutex))) {
 607                 ret = -EBUSY;
 608                 goto out;
 609         }
 610
 611         vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
 612         if (!vsock) {
 613                 ret = -ENOMEM;
 614                 goto out;
 615         }
 616
 617         vsock->vdev = vdev;
 618
 619         ret = virtio_find_vqs(vsock->vdev, VSOCK_VQ_MAX,
 620                               vsock->vqs, callbacks, names,
 621                               NULL);
 622         if (ret < 0)
 623                 goto out;
 624
 625         virtio_vsock_update_guest_cid(vsock);
 626
 627         vsock->rx_buf_nr = 0;
 628         vsock->rx_buf_max_nr = 0;
 629         atomic_set(&vsock->queued_replies, 0);
 630
 631         mutex_init(&vsock->tx_lock);
 632         mutex_init(&vsock->rx_lock);
 633         mutex_init(&vsock->event_lock);
 634         spin_lock_init(&vsock->send_pkt_list_lock);
 635         INIT_LIST_HEAD(&vsock->send_pkt_list);
 636         spin_lock_init(&vsock->loopback_list_lock);
 637         INIT_LIST_HEAD(&vsock->loopback_list);
 638         INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
 639         INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
 640         INIT_WORK(&vsock->event_work, virtio_transport_event_work);
 641         INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
 642         INIT_WORK(&vsock->loopback_work, virtio_transport_loopback_work);
 643
 644         mutex_lock(&vsock->tx_lock);
 645         vsock->tx_run = true;
 646         mutex_unlock(&vsock->tx_lock);
 647
 648         mutex_lock(&vsock->rx_lock);
 649         virtio_vsock_rx_fill(vsock);
 650         vsock->rx_run = true;
 651         mutex_unlock(&vsock->rx_lock);
 652
 653         mutex_lock(&vsock->event_lock);
 654         virtio_vsock_event_fill(vsock);
 655         vsock->event_run = true;
 656         mutex_unlock(&vsock->event_lock);
 657
 658         vdev->priv = vsock;
 659         rcu_assign_pointer(the_virtio_vsock, vsock);
 660
 661         mutex_unlock(&the_virtio_vsock_mutex);
 662         return 0;
 663
 664 out:
 665         kfree(vsock);
 666         mutex_unlock(&the_virtio_vsock_mutex);
 667         return ret;
 668 }
 669
 670 static void virtio_vsock_remove(struct virtio_device *vdev)
 671 {
 672         struct virtio_vsock *vsock = vdev->priv;
 673         struct virtio_vsock_pkt *pkt;
 674
 675         mutex_lock(&the_virtio_vsock_mutex);
 676
 677         vdev->priv = NULL;
 678         rcu_assign_pointer(the_virtio_vsock, NULL);
 679         synchronize_rcu();
 680
 681         /* Reset all connected sockets when the device disappear */
 682         vsock_for_each_connected_socket(virtio_vsock_reset_sock);
 683
 684         /* Stop all work handlers to make sure no one is accessing the device,
 685          * so we can safely call vdev->config->reset().
 686          */
 687         mutex_lock(&vsock->rx_lock);
 688         vsock->rx_run = false;
 689         mutex_unlock(&vsock->rx_lock);
 690
 691         mutex_lock(&vsock->tx_lock);
 692         vsock->tx_run = false;
 693         mutex_unlock(&vsock->tx_lock);
 694
 695         mutex_lock(&vsock->event_lock);
 696         vsock->event_run = false;
 697         mutex_unlock(&vsock->event_lock);
 698
 699         /* Flush all device writes and interrupts, device will not use any
 700          * more buffers.
 701          */
 702         vdev->config->reset(vdev);
 703
 704         mutex_lock(&vsock->rx_lock);
 705         while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
 706                 virtio_transport_free_pkt(pkt);
 707         mutex_unlock(&vsock->rx_lock);
 708
 709         mutex_lock(&vsock->tx_lock);
 710         while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
 711                 virtio_transport_free_pkt(pkt);
 712         mutex_unlock(&vsock->tx_lock);
 713
 714         spin_lock_bh(&vsock->send_pkt_list_lock);
 715         while (!list_empty(&vsock->send_pkt_list)) {
 716                 pkt = list_first_entry(&vsock->send_pkt_list,
 717                                        struct virtio_vsock_pkt, list);
 718                 list_del(&pkt->list);
 719                 virtio_transport_free_pkt(pkt);
 720         }
 721         spin_unlock_bh(&vsock->send_pkt_list_lock);
 722
 723         spin_lock_bh(&vsock->loopback_list_lock);
 724         while (!list_empty(&vsock->loopback_list)) {
 725                 pkt = list_first_entry(&vsock->loopback_list,
 726                                        struct virtio_vsock_pkt, list);
 727                 list_del(&pkt->list);
 728                 virtio_transport_free_pkt(pkt);
 729         }
 730         spin_unlock_bh(&vsock->loopback_list_lock);
 731
 732         /* Delete virtqueues and flush outstanding callbacks if any */
 733         vdev->config->del_vqs(vdev);
 734
 735         /* Other works can be queued before 'config->del_vqs()', so we flush
 736          * all works before to free the vsock object to avoid use after free.
 737          */
 738         flush_work(&vsock->loopback_work);
 739         flush_work(&vsock->rx_work);
 740         flush_work(&vsock->tx_work);
 741         flush_work(&vsock->event_work);
 742         flush_work(&vsock->send_pkt_work);
 743
 744         mutex_unlock(&the_virtio_vsock_mutex);
 745
 746         kfree(vsock);
 747 }
 748
 749 static struct virtio_device_id id_table[] = {
 750         { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
 751         { 0 },
 752 };
 753
 754 static unsigned int features[] = {
 755 };
 756
 757 static struct virtio_driver virtio_vsock_driver = {
 758         .feature_table = features,
 759         .feature_table_size = ARRAY_SIZE(features),
 760         .driver.name = KBUILD_MODNAME,
 761         .driver.owner = THIS_MODULE,
 762         .id_table = id_table,
 763         .probe = virtio_vsock_probe,
 764         .remove = virtio_vsock_remove,
 765 };
 766
 767 static int __init virtio_vsock_init(void)
 768 {
 769         int ret;
 770
 771         virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
 772         if (!virtio_vsock_workqueue)
 773                 return -ENOMEM;
 774
 775         ret = vsock_core_register(&virtio_transport.transport,
 776                                   VSOCK_TRANSPORT_F_G2H);
 777         if (ret)
 778                 goto out_wq;
 779
 780         ret = register_virtio_driver(&virtio_vsock_driver);
 781         if (ret)
 782                 goto out_vci;
 783
 784         return 0;
 785
 786 out_vci:
 787         vsock_core_unregister(&virtio_transport.transport);
 788 out_wq:
 789         destroy_workqueue(virtio_vsock_workqueue);
 790         return ret;
 791 }
 792
 793 static void __exit virtio_vsock_exit(void)
 794 {
 795         unregister_virtio_driver(&virtio_vsock_driver);
 796         vsock_core_unregister(&virtio_transport.transport);
 797         destroy_workqueue(virtio_vsock_workqueue);
 798 }
 799
 800 module_init(virtio_vsock_init);
 801 module_exit(virtio_vsock_exit);
 802 MODULE_LICENSE("GPL v2");
 803 MODULE_AUTHOR("Asias He");
 804 MODULE_DESCRIPTION("virtio transport for vsock");
 805 MODULE_DEVICE_TABLE(virtio, id_table);