Pileus Git - ~andy/linux/blob - drivers/vhost/net.c

   1 /* Copyright (C) 2009 Red Hat, Inc.
   2  * Author: Michael S. Tsirkin <mst@redhat.com>
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2.
   5  *
   6  * virtio-net server in host kernel.
   7  */
   8
   9 #include <linux/compat.h>
  10 #include <linux/eventfd.h>
  11 #include <linux/vhost.h>
  12 #include <linux/virtio_net.h>
  13 #include <linux/mmu_context.h>
  14 #include <linux/miscdevice.h>
  15 #include <linux/module.h>
  16 #include <linux/mutex.h>
  17 #include <linux/workqueue.h>
  18 #include <linux/rcupdate.h>
  19 #include <linux/file.h>
  20 #include <linux/slab.h>
  21
  22 #include <linux/net.h>
  23 #include <linux/if_packet.h>
  24 #include <linux/if_arp.h>
  25 #include <linux/if_tun.h>
  26 #include <linux/if_macvlan.h>
  27
  28 #include <net/sock.h>
  29
  30 #include "vhost.h"
  31
  32 /* Max number of bytes transferred before requeueing the job.
  33  * Using this limit prevents one virtqueue from starving others. */
  34 #define VHOST_NET_WEIGHT 0x80000
  35
  36 enum {
  37         VHOST_NET_VQ_RX = 0,
  38         VHOST_NET_VQ_TX = 1,
  39         VHOST_NET_VQ_MAX = 2,
  40 };
  41
  42 enum vhost_net_poll_state {
  43         VHOST_NET_POLL_DISABLED = 0,
  44         VHOST_NET_POLL_STARTED = 1,
  45         VHOST_NET_POLL_STOPPED = 2,
  46 };
  47
  48 struct vhost_net {
  49         struct vhost_dev dev;
  50         struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX];
  51         struct vhost_poll poll[VHOST_NET_VQ_MAX];
  52         /* Tells us whether we are polling a socket for TX.
  53          * We only do this when socket buffer fills up.
  54          * Protected by tx vq lock. */
  55         enum vhost_net_poll_state tx_poll_state;
  56 };
  57
  58 /* Pop first len bytes from iovec. Return number of segments used. */
  59 static int move_iovec_hdr(struct iovec *from, struct iovec *to,
  60                           size_t len, int iov_count)
  61 {
  62         int seg = 0;
  63         size_t size;
  64         while (len && seg < iov_count) {
  65                 size = min(from->iov_len, len);
  66                 to->iov_base = from->iov_base;
  67                 to->iov_len = size;
  68                 from->iov_len -= size;
  69                 from->iov_base += size;
  70                 len -= size;
  71                 ++from;
  72                 ++to;
  73                 ++seg;
  74         }
  75         return seg;
  76 }
  77
  78 /* Caller must have TX VQ lock */
  79 static void tx_poll_stop(struct vhost_net *net)
  80 {
  81         if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED))
  82                 return;
  83         vhost_poll_stop(net->poll + VHOST_NET_VQ_TX);
  84         net->tx_poll_state = VHOST_NET_POLL_STOPPED;
  85 }
  86
  87 /* Caller must have TX VQ lock */
  88 static void tx_poll_start(struct vhost_net *net, struct socket *sock)
  89 {
  90         if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED))
  91                 return;
  92         vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file);
  93         net->tx_poll_state = VHOST_NET_POLL_STARTED;
  94 }
  95
  96 /* Expects to be always run from workqueue - which acts as
  97  * read-size critical section for our kind of RCU. */
  98 static void handle_tx(struct vhost_net *net)
  99 {
 100         struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX];
 101         unsigned out, in, s;
 102         int head;
 103         struct msghdr msg = {
 104                 .msg_name = NULL,
 105                 .msg_namelen = 0,
 106                 .msg_control = NULL,
 107                 .msg_controllen = 0,
 108                 .msg_iov = vq->iov,
 109                 .msg_flags = MSG_DONTWAIT,
 110         };
 111         size_t len, total_len = 0;
 112         int err, wmem;
 113         size_t hdr_size;
 114         struct socket *sock = rcu_dereference(vq->private_data);
 115         if (!sock)
 116                 return;
 117
 118         wmem = atomic_read(&sock->sk->sk_wmem_alloc);
 119         if (wmem >= sock->sk->sk_sndbuf) {
 120                 mutex_lock(&vq->mutex);
 121                 tx_poll_start(net, sock);
 122                 mutex_unlock(&vq->mutex);
 123                 return;
 124         }
 125
 126         use_mm(net->dev.mm);
 127         mutex_lock(&vq->mutex);
 128         vhost_disable_notify(vq);
 129
 130         if (wmem < sock->sk->sk_sndbuf / 2)
 131                 tx_poll_stop(net);
 132         hdr_size = vq->hdr_size;
 133
 134         for (;;) {
 135                 head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
 136                                          ARRAY_SIZE(vq->iov),
 137                                          &out, &in,
 138                                          NULL, NULL);
 139                 /* On error, stop handling until the next kick. */
 140                 if (unlikely(head < 0))
 141                         break;
 142                 /* Nothing new?  Wait for eventfd to tell us they refilled. */
 143                 if (head == vq->num) {
 144                         wmem = atomic_read(&sock->sk->sk_wmem_alloc);
 145                         if (wmem >= sock->sk->sk_sndbuf * 3 / 4) {
 146                                 tx_poll_start(net, sock);
 147                                 set_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
 148                                 break;
 149                         }
 150                         if (unlikely(vhost_enable_notify(vq))) {
 151                                 vhost_disable_notify(vq);
 152                                 continue;
 153                         }
 154                         break;
 155                 }
 156                 if (in) {
 157                         vq_err(vq, "Unexpected descriptor format for TX: "
 158                                "out %d, int %d\n", out, in);
 159                         break;
 160                 }
 161                 /* Skip header. TODO: support TSO. */
 162                 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out);
 163                 msg.msg_iovlen = out;
 164                 len = iov_length(vq->iov, out);
 165                 /* Sanity check */
 166                 if (!len) {
 167                         vq_err(vq, "Unexpected header len for TX: "
 168                                "%zd expected %zd\n",
 169                                iov_length(vq->hdr, s), hdr_size);
 170                         break;
 171                 }
 172                 /* TODO: Check specific error and bomb out unless ENOBUFS? */
 173                 err = sock->ops->sendmsg(NULL, sock, &msg, len);
 174                 if (unlikely(err < 0)) {
 175                         vhost_discard_vq_desc(vq);
 176                         tx_poll_start(net, sock);
 177                         break;
 178                 }
 179                 if (err != len)
 180                         pr_debug("Truncated TX packet: "
 181                                  " len %d != %zd\n", err, len);
 182                 vhost_add_used_and_signal(&net->dev, vq, head, 0);
 183                 total_len += len;
 184                 if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
 185                         vhost_poll_queue(&vq->poll);
 186                         break;
 187                 }
 188         }
 189
 190         mutex_unlock(&vq->mutex);
 191         unuse_mm(net->dev.mm);
 192 }
 193
 194 /* Expects to be always run from workqueue - which acts as
 195  * read-size critical section for our kind of RCU. */
 196 static void handle_rx(struct vhost_net *net)
 197 {
 198         struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
 199         unsigned out, in, log, s;
 200         int head;
 201         struct vhost_log *vq_log;
 202         struct msghdr msg = {
 203                 .msg_name = NULL,
 204                 .msg_namelen = 0,
 205                 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
 206                 .msg_controllen = 0,
 207                 .msg_iov = vq->iov,
 208                 .msg_flags = MSG_DONTWAIT,
 209         };
 210
 211         struct virtio_net_hdr hdr = {
 212                 .flags = 0,
 213                 .gso_type = VIRTIO_NET_HDR_GSO_NONE
 214         };
 215
 216         size_t len, total_len = 0;
 217         int err;
 218         size_t hdr_size;
 219         struct socket *sock = rcu_dereference(vq->private_data);
 220         if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue))
 221                 return;
 222
 223         use_mm(net->dev.mm);
 224         mutex_lock(&vq->mutex);
 225         vhost_disable_notify(vq);
 226         hdr_size = vq->hdr_size;
 227
 228         vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
 229                 vq->log : NULL;
 230
 231         for (;;) {
 232                 head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
 233                                          ARRAY_SIZE(vq->iov),
 234                                          &out, &in,
 235                                          vq_log, &log);
 236                 /* On error, stop handling until the next kick. */
 237                 if (unlikely(head < 0))
 238                         break;
 239                 /* OK, now we need to know about added descriptors. */
 240                 if (head == vq->num) {
 241                         if (unlikely(vhost_enable_notify(vq))) {
 242                                 /* They have slipped one in as we were
 243                                  * doing that: check again. */
 244                                 vhost_disable_notify(vq);
 245                                 continue;
 246                         }
 247                         /* Nothing new?  Wait for eventfd to tell us
 248                          * they refilled. */
 249                         break;
 250                 }
 251                 /* We don't need to be notified again. */
 252                 if (out) {
 253                         vq_err(vq, "Unexpected descriptor format for RX: "
 254                                "out %d, int %d\n",
 255                                out, in);
 256                         break;
 257                 }
 258                 /* Skip header. TODO: support TSO/mergeable rx buffers. */
 259                 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, in);
 260                 msg.msg_iovlen = in;
 261                 len = iov_length(vq->iov, in);
 262                 /* Sanity check */
 263                 if (!len) {
 264                         vq_err(vq, "Unexpected header len for RX: "
 265                                "%zd expected %zd\n",
 266                                iov_length(vq->hdr, s), hdr_size);
 267                         break;
 268                 }
 269                 err = sock->ops->recvmsg(NULL, sock, &msg,
 270                                          len, MSG_DONTWAIT | MSG_TRUNC);
 271                 /* TODO: Check specific error and bomb out unless EAGAIN? */
 272                 if (err < 0) {
 273                         vhost_discard_vq_desc(vq);
 274                         break;
 275                 }
 276                 /* TODO: Should check and handle checksum. */
 277                 if (err > len) {
 278                         pr_debug("Discarded truncated rx packet: "
 279                                  " len %d > %zd\n", err, len);
 280                         vhost_discard_vq_desc(vq);
 281                         continue;
 282                 }
 283                 len = err;
 284                 err = memcpy_toiovec(vq->hdr, (unsigned char *)&hdr, hdr_size);
 285                 if (err) {
 286                         vq_err(vq, "Unable to write vnet_hdr at addr %p: %d\n",
 287                                vq->iov->iov_base, err);
 288                         break;
 289                 }
 290                 len += hdr_size;
 291                 vhost_add_used_and_signal(&net->dev, vq, head, len);
 292                 if (unlikely(vq_log))
 293                         vhost_log_write(vq, vq_log, log, len);
 294                 total_len += len;
 295                 if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
 296                         vhost_poll_queue(&vq->poll);
 297                         break;
 298                 }
 299         }
 300
 301         mutex_unlock(&vq->mutex);
 302         unuse_mm(net->dev.mm);
 303 }
 304
 305 static void handle_tx_kick(struct vhost_work *work)
 306 {
 307         struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
 308                                                   poll.work);
 309         struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
 310
 311         handle_tx(net);
 312 }
 313
 314 static void handle_rx_kick(struct vhost_work *work)
 315 {
 316         struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
 317                                                   poll.work);
 318         struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
 319
 320         handle_rx(net);
 321 }
 322
 323 static void handle_tx_net(struct vhost_work *work)
 324 {
 325         struct vhost_net *net = container_of(work, struct vhost_net,
 326                                              poll[VHOST_NET_VQ_TX].work);
 327         handle_tx(net);
 328 }
 329
 330 static void handle_rx_net(struct vhost_work *work)
 331 {
 332         struct vhost_net *net = container_of(work, struct vhost_net,
 333                                              poll[VHOST_NET_VQ_RX].work);
 334         handle_rx(net);
 335 }
 336
 337 static int vhost_net_open(struct inode *inode, struct file *f)
 338 {
 339         struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL);
 340         struct vhost_dev *dev;
 341         int r;
 342
 343         if (!n)
 344                 return -ENOMEM;
 345
 346         dev = &n->dev;
 347         n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick;
 348         n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick;
 349         r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX);
 350         if (r < 0) {
 351                 kfree(n);
 352                 return r;
 353         }
 354
 355         vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev);
 356         vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev);
 357         n->tx_poll_state = VHOST_NET_POLL_DISABLED;
 358
 359         f->private_data = n;
 360
 361         return 0;
 362 }
 363
 364 static void vhost_net_disable_vq(struct vhost_net *n,
 365                                  struct vhost_virtqueue *vq)
 366 {
 367         if (!vq->private_data)
 368                 return;
 369         if (vq == n->vqs + VHOST_NET_VQ_TX) {
 370                 tx_poll_stop(n);
 371                 n->tx_poll_state = VHOST_NET_POLL_DISABLED;
 372         } else
 373                 vhost_poll_stop(n->poll + VHOST_NET_VQ_RX);
 374 }
 375
 376 static void vhost_net_enable_vq(struct vhost_net *n,
 377                                 struct vhost_virtqueue *vq)
 378 {
 379         struct socket *sock = vq->private_data;
 380         if (!sock)
 381                 return;
 382         if (vq == n->vqs + VHOST_NET_VQ_TX) {
 383                 n->tx_poll_state = VHOST_NET_POLL_STOPPED;
 384                 tx_poll_start(n, sock);
 385         } else
 386                 vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file);
 387 }
 388
 389 static struct socket *vhost_net_stop_vq(struct vhost_net *n,
 390                                         struct vhost_virtqueue *vq)
 391 {
 392         struct socket *sock;
 393
 394         mutex_lock(&vq->mutex);
 395         sock = vq->private_data;
 396         vhost_net_disable_vq(n, vq);
 397         rcu_assign_pointer(vq->private_data, NULL);
 398         mutex_unlock(&vq->mutex);
 399         return sock;
 400 }
 401
 402 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
 403                            struct socket **rx_sock)
 404 {
 405         *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX);
 406         *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX);
 407 }
 408
 409 static void vhost_net_flush_vq(struct vhost_net *n, int index)
 410 {
 411         vhost_poll_flush(n->poll + index);
 412         vhost_poll_flush(&n->dev.vqs[index].poll);
 413 }
 414
 415 static void vhost_net_flush(struct vhost_net *n)
 416 {
 417         vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
 418         vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
 419 }
 420
 421 static int vhost_net_release(struct inode *inode, struct file *f)
 422 {
 423         struct vhost_net *n = f->private_data;
 424         struct socket *tx_sock;
 425         struct socket *rx_sock;
 426
 427         vhost_net_stop(n, &tx_sock, &rx_sock);
 428         vhost_net_flush(n);
 429         vhost_dev_cleanup(&n->dev);
 430         if (tx_sock)
 431                 fput(tx_sock->file);
 432         if (rx_sock)
 433                 fput(rx_sock->file);
 434         /* We do an extra flush before freeing memory,
 435          * since jobs can re-queue themselves. */
 436         vhost_net_flush(n);
 437         kfree(n);
 438         return 0;
 439 }
 440
 441 static struct socket *get_raw_socket(int fd)
 442 {
 443         struct {
 444                 struct sockaddr_ll sa;
 445                 char  buf[MAX_ADDR_LEN];
 446         } uaddr;
 447         int uaddr_len = sizeof uaddr, r;
 448         struct socket *sock = sockfd_lookup(fd, &r);
 449         if (!sock)
 450                 return ERR_PTR(-ENOTSOCK);
 451
 452         /* Parameter checking */
 453         if (sock->sk->sk_type != SOCK_RAW) {
 454                 r = -ESOCKTNOSUPPORT;
 455                 goto err;
 456         }
 457
 458         r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa,
 459                                &uaddr_len, 0);
 460         if (r)
 461                 goto err;
 462
 463         if (uaddr.sa.sll_family != AF_PACKET) {
 464                 r = -EPFNOSUPPORT;
 465                 goto err;
 466         }
 467         return sock;
 468 err:
 469         fput(sock->file);
 470         return ERR_PTR(r);
 471 }
 472
 473 static struct socket *get_tap_socket(int fd)
 474 {
 475         struct file *file = fget(fd);
 476         struct socket *sock;
 477         if (!file)
 478                 return ERR_PTR(-EBADF);
 479         sock = tun_get_socket(file);
 480         if (!IS_ERR(sock))
 481                 return sock;
 482         sock = macvtap_get_socket(file);
 483         if (IS_ERR(sock))
 484                 fput(file);
 485         return sock;
 486 }
 487
 488 static struct socket *get_socket(int fd)
 489 {
 490         struct socket *sock;
 491         /* special case to disable backend */
 492         if (fd == -1)
 493                 return NULL;
 494         sock = get_raw_socket(fd);
 495         if (!IS_ERR(sock))
 496                 return sock;
 497         sock = get_tap_socket(fd);
 498         if (!IS_ERR(sock))
 499                 return sock;
 500         return ERR_PTR(-ENOTSOCK);
 501 }
 502
 503 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
 504 {
 505         struct socket *sock, *oldsock;
 506         struct vhost_virtqueue *vq;
 507         int r;
 508
 509         mutex_lock(&n->dev.mutex);
 510         r = vhost_dev_check_owner(&n->dev);
 511         if (r)
 512                 goto err;
 513
 514         if (index >= VHOST_NET_VQ_MAX) {
 515                 r = -ENOBUFS;
 516                 goto err;
 517         }
 518         vq = n->vqs + index;
 519         mutex_lock(&vq->mutex);
 520
 521         /* Verify that ring has been setup correctly. */
 522         if (!vhost_vq_access_ok(vq)) {
 523                 r = -EFAULT;
 524                 goto err_vq;
 525         }
 526         sock = get_socket(fd);
 527         if (IS_ERR(sock)) {
 528                 r = PTR_ERR(sock);
 529                 goto err_vq;
 530         }
 531
 532         /* start polling new socket */
 533         oldsock = vq->private_data;
 534         if (sock != oldsock) {
 535                 vhost_net_disable_vq(n, vq);
 536                 rcu_assign_pointer(vq->private_data, sock);
 537                 vhost_net_enable_vq(n, vq);
 538         }
 539
 540         mutex_unlock(&vq->mutex);
 541
 542         if (oldsock) {
 543                 vhost_net_flush_vq(n, index);
 544                 fput(oldsock->file);
 545         }
 546
 547         mutex_unlock(&n->dev.mutex);
 548         return 0;
 549
 550 err_vq:
 551         mutex_unlock(&vq->mutex);
 552 err:
 553         mutex_unlock(&n->dev.mutex);
 554         return r;
 555 }
 556
 557 static long vhost_net_reset_owner(struct vhost_net *n)
 558 {
 559         struct socket *tx_sock = NULL;
 560         struct socket *rx_sock = NULL;
 561         long err;
 562         mutex_lock(&n->dev.mutex);
 563         err = vhost_dev_check_owner(&n->dev);
 564         if (err)
 565                 goto done;
 566         vhost_net_stop(n, &tx_sock, &rx_sock);
 567         vhost_net_flush(n);
 568         err = vhost_dev_reset_owner(&n->dev);
 569 done:
 570         mutex_unlock(&n->dev.mutex);
 571         if (tx_sock)
 572                 fput(tx_sock->file);
 573         if (rx_sock)
 574                 fput(rx_sock->file);
 575         return err;
 576 }
 577
 578 static int vhost_net_set_features(struct vhost_net *n, u64 features)
 579 {
 580         size_t hdr_size = features & (1 << VHOST_NET_F_VIRTIO_NET_HDR) ?
 581                 sizeof(struct virtio_net_hdr) : 0;
 582         int i;
 583         mutex_lock(&n->dev.mutex);
 584         if ((features & (1 << VHOST_F_LOG_ALL)) &&
 585             !vhost_log_access_ok(&n->dev)) {
 586                 mutex_unlock(&n->dev.mutex);
 587                 return -EFAULT;
 588         }
 589         n->dev.acked_features = features;
 590         smp_wmb();
 591         for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
 592                 mutex_lock(&n->vqs[i].mutex);
 593                 n->vqs[i].hdr_size = hdr_size;
 594                 mutex_unlock(&n->vqs[i].mutex);
 595         }
 596         vhost_net_flush(n);
 597         mutex_unlock(&n->dev.mutex);
 598         return 0;
 599 }
 600
 601 static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
 602                             unsigned long arg)
 603 {
 604         struct vhost_net *n = f->private_data;
 605         void __user *argp = (void __user *)arg;
 606         u64 __user *featurep = argp;
 607         struct vhost_vring_file backend;
 608         u64 features;
 609         int r;
 610         switch (ioctl) {
 611         case VHOST_NET_SET_BACKEND:
 612                 if (copy_from_user(&backend, argp, sizeof backend))
 613                         return -EFAULT;
 614                 return vhost_net_set_backend(n, backend.index, backend.fd);
 615         case VHOST_GET_FEATURES:
 616                 features = VHOST_FEATURES;
 617                 if (copy_to_user(featurep, &features, sizeof features))
 618                         return -EFAULT;
 619                 return 0;
 620         case VHOST_SET_FEATURES:
 621                 if (copy_from_user(&features, featurep, sizeof features))
 622                         return -EFAULT;
 623                 if (features & ~VHOST_FEATURES)
 624                         return -EOPNOTSUPP;
 625                 return vhost_net_set_features(n, features);
 626         case VHOST_RESET_OWNER:
 627                 return vhost_net_reset_owner(n);
 628         default:
 629                 mutex_lock(&n->dev.mutex);
 630                 r = vhost_dev_ioctl(&n->dev, ioctl, arg);
 631                 vhost_net_flush(n);
 632                 mutex_unlock(&n->dev.mutex);
 633                 return r;
 634         }
 635 }
 636
 637 #ifdef CONFIG_COMPAT
 638 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl,
 639                                    unsigned long arg)
 640 {
 641         return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
 642 }
 643 #endif
 644
 645 static const struct file_operations vhost_net_fops = {
 646         .owner          = THIS_MODULE,
 647         .release        = vhost_net_release,
 648         .unlocked_ioctl = vhost_net_ioctl,
 649 #ifdef CONFIG_COMPAT
 650         .compat_ioctl   = vhost_net_compat_ioctl,
 651 #endif
 652         .open           = vhost_net_open,
 653 };
 654
 655 static struct miscdevice vhost_net_misc = {
 656         VHOST_NET_MINOR,
 657         "vhost-net",
 658         &vhost_net_fops,
 659 };
 660
 661 static int vhost_net_init(void)
 662 {
 663         return misc_register(&vhost_net_misc);
 664 }
 665 module_init(vhost_net_init);
 666
 667 static void vhost_net_exit(void)
 668 {
 669         misc_deregister(&vhost_net_misc);
 670 }
 671 module_exit(vhost_net_exit);
 672
 673 MODULE_VERSION("0.0.1");
 674 MODULE_LICENSE("GPL v2");
 675 MODULE_AUTHOR("Michael S. Tsirkin");
 676 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");