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/miscdevice.h>
  14 #include <linux/module.h>
  15 #include <linux/moduleparam.h>
  16 #include <linux/mutex.h>
  17 #include <linux/workqueue.h>
  18 #include <linux/file.h>
  19 #include <linux/slab.h>
  20 #include <linux/sched/clock.h>
  21 #include <linux/sched/signal.h>
  22 #include <linux/vmalloc.h>
  23
  24 #include <linux/net.h>
  25 #include <linux/if_packet.h>
  26 #include <linux/if_arp.h>
  27 #include <linux/if_tun.h>
  28 #include <linux/if_macvlan.h>
  29 #include <linux/if_tap.h>
  30 #include <linux/if_vlan.h>
  31 #include <linux/skb_array.h>
  32 #include <linux/skbuff.h>
  33
  34 #include <net/sock.h>
  35
  36 #include "vhost.h"
  37
  38 static int experimental_zcopytx = 1;
  39 module_param(experimental_zcopytx, int, 0444);
  40 MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
  41                                        " 1 -Enable; 0 - Disable");
  42
  43 /* Max number of bytes transferred before requeueing the job.
  44  * Using this limit prevents one virtqueue from starving others. */
  45 #define VHOST_NET_WEIGHT 0x80000
  46
  47 /* MAX number of TX used buffers for outstanding zerocopy */
  48 #define VHOST_MAX_PEND 128
  49 #define VHOST_GOODCOPY_LEN 256
  50
  51 /*
  52  * For transmit, used buffer len is unused; we override it to track buffer
  53  * status internally; used for zerocopy tx only.
  54  */
  55 /* Lower device DMA failed */
  56 #define VHOST_DMA_FAILED_LEN    ((__force __virtio32)3)
  57 /* Lower device DMA done */
  58 #define VHOST_DMA_DONE_LEN      ((__force __virtio32)2)
  59 /* Lower device DMA in progress */
  60 #define VHOST_DMA_IN_PROGRESS   ((__force __virtio32)1)
  61 /* Buffer unused */
  62 #define VHOST_DMA_CLEAR_LEN     ((__force __virtio32)0)
  63
  64 #define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN)
  65
  66 enum {
  67         VHOST_NET_FEATURES = VHOST_FEATURES |
  68                          (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
  69                          (1ULL << VIRTIO_NET_F_MRG_RXBUF) |
  70                          (1ULL << VIRTIO_F_IOMMU_PLATFORM)
  71 };
  72
  73 enum {
  74         VHOST_NET_VQ_RX = 0,
  75         VHOST_NET_VQ_TX = 1,
  76         VHOST_NET_VQ_MAX = 2,
  77 };
  78
  79 struct vhost_net_ubuf_ref {
  80         /* refcount follows semantics similar to kref:
  81          *  0: object is released
  82          *  1: no outstanding ubufs
  83          * >1: outstanding ubufs
  84          */
  85         atomic_t refcount;
  86         wait_queue_head_t wait;
  87         struct vhost_virtqueue *vq;
  88 };
  89
  90 #define VHOST_RX_BATCH 64
  91 struct vhost_net_buf {
  92         struct sk_buff **queue;
  93         int tail;
  94         int head;
  95 };
  96
  97 struct vhost_net_virtqueue {
  98         struct vhost_virtqueue vq;
  99         size_t vhost_hlen;
 100         size_t sock_hlen;
 101         /* vhost zerocopy support fields below: */
 102         /* last used idx for outstanding DMA zerocopy buffers */
 103         int upend_idx;
 104         /* first used idx for DMA done zerocopy buffers */
 105         int done_idx;
 106         /* an array of userspace buffers info */
 107         struct ubuf_info *ubuf_info;
 108         /* Reference counting for outstanding ubufs.
 109          * Protected by vq mutex. Writers must also take device mutex. */
 110         struct vhost_net_ubuf_ref *ubufs;
 111         struct skb_array *rx_array;
 112         struct vhost_net_buf rxq;
 113 };
 114
 115 struct vhost_net {
 116         struct vhost_dev dev;
 117         struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX];
 118         struct vhost_poll poll[VHOST_NET_VQ_MAX];
 119         /* Number of TX recently submitted.
 120          * Protected by tx vq lock. */
 121         unsigned tx_packets;
 122         /* Number of times zerocopy TX recently failed.
 123          * Protected by tx vq lock. */
 124         unsigned tx_zcopy_err;
 125         /* Flush in progress. Protected by tx vq lock. */
 126         bool tx_flush;
 127 };
 128
 129 static unsigned vhost_net_zcopy_mask __read_mostly;
 130
 131 static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq)
 132 {
 133         if (rxq->tail != rxq->head)
 134                 return rxq->queue[rxq->head];
 135         else
 136                 return NULL;
 137 }
 138
 139 static int vhost_net_buf_get_size(struct vhost_net_buf *rxq)
 140 {
 141         return rxq->tail - rxq->head;
 142 }
 143
 144 static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq)
 145 {
 146         return rxq->tail == rxq->head;
 147 }
 148
 149 static void *vhost_net_buf_consume(struct vhost_net_buf *rxq)
 150 {
 151         void *ret = vhost_net_buf_get_ptr(rxq);
 152         ++rxq->head;
 153         return ret;
 154 }
 155
 156 static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq)
 157 {
 158         struct vhost_net_buf *rxq = &nvq->rxq;
 159
 160         rxq->head = 0;
 161         rxq->tail = skb_array_consume_batched(nvq->rx_array, rxq->queue,
 162                                               VHOST_RX_BATCH);
 163         return rxq->tail;
 164 }
 165
 166 static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq)
 167 {
 168         struct vhost_net_buf *rxq = &nvq->rxq;
 169
 170         if (nvq->rx_array && !vhost_net_buf_is_empty(rxq)) {
 171                 skb_array_unconsume(nvq->rx_array, rxq->queue + rxq->head,
 172                                     vhost_net_buf_get_size(rxq));
 173                 rxq->head = rxq->tail = 0;
 174         }
 175 }
 176
 177 static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq)
 178 {
 179         struct vhost_net_buf *rxq = &nvq->rxq;
 180
 181         if (!vhost_net_buf_is_empty(rxq))
 182                 goto out;
 183
 184         if (!vhost_net_buf_produce(nvq))
 185                 return 0;
 186
 187 out:
 188         return __skb_array_len_with_tag(vhost_net_buf_get_ptr(rxq));
 189 }
 190
 191 static void vhost_net_buf_init(struct vhost_net_buf *rxq)
 192 {
 193         rxq->head = rxq->tail = 0;
 194 }
 195
 196 static void vhost_net_enable_zcopy(int vq)
 197 {
 198         vhost_net_zcopy_mask |= 0x1 << vq;
 199 }
 200
 201 static struct vhost_net_ubuf_ref *
 202 vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
 203 {
 204         struct vhost_net_ubuf_ref *ubufs;
 205         /* No zero copy backend? Nothing to count. */
 206         if (!zcopy)
 207                 return NULL;
 208         ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL);
 209         if (!ubufs)
 210                 return ERR_PTR(-ENOMEM);
 211         atomic_set(&ubufs->refcount, 1);
 212         init_waitqueue_head(&ubufs->wait);
 213         ubufs->vq = vq;
 214         return ubufs;
 215 }
 216
 217 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
 218 {
 219         int r = atomic_sub_return(1, &ubufs->refcount);
 220         if (unlikely(!r))
 221                 wake_up(&ubufs->wait);
 222         return r;
 223 }
 224
 225 static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs)
 226 {
 227         vhost_net_ubuf_put(ubufs);
 228         wait_event(ubufs->wait, !atomic_read(&ubufs->refcount));
 229 }
 230
 231 static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs)
 232 {
 233         vhost_net_ubuf_put_and_wait(ubufs);
 234         kfree(ubufs);
 235 }
 236
 237 static void vhost_net_clear_ubuf_info(struct vhost_net *n)
 238 {
 239         int i;
 240
 241         for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
 242                 kfree(n->vqs[i].ubuf_info);
 243                 n->vqs[i].ubuf_info = NULL;
 244         }
 245 }
 246
 247 static int vhost_net_set_ubuf_info(struct vhost_net *n)
 248 {
 249         bool zcopy;
 250         int i;
 251
 252         for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
 253                 zcopy = vhost_net_zcopy_mask & (0x1 << i);
 254                 if (!zcopy)
 255                         continue;
 256                 n->vqs[i].ubuf_info = kmalloc(sizeof(*n->vqs[i].ubuf_info) *
 257                                               UIO_MAXIOV, GFP_KERNEL);
 258                 if  (!n->vqs[i].ubuf_info)
 259                         goto err;
 260         }
 261         return 0;
 262
 263 err:
 264         vhost_net_clear_ubuf_info(n);
 265         return -ENOMEM;
 266 }
 267
 268 static void vhost_net_vq_reset(struct vhost_net *n)
 269 {
 270         int i;
 271
 272         vhost_net_clear_ubuf_info(n);
 273
 274         for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
 275                 n->vqs[i].done_idx = 0;
 276                 n->vqs[i].upend_idx = 0;
 277                 n->vqs[i].ubufs = NULL;
 278                 n->vqs[i].vhost_hlen = 0;
 279                 n->vqs[i].sock_hlen = 0;
 280                 vhost_net_buf_init(&n->vqs[i].rxq);
 281         }
 282
 283 }
 284
 285 static void vhost_net_tx_packet(struct vhost_net *net)
 286 {
 287         ++net->tx_packets;
 288         if (net->tx_packets < 1024)
 289                 return;
 290         net->tx_packets = 0;
 291         net->tx_zcopy_err = 0;
 292 }
 293
 294 static void vhost_net_tx_err(struct vhost_net *net)
 295 {
 296         ++net->tx_zcopy_err;
 297 }
 298
 299 static bool vhost_net_tx_select_zcopy(struct vhost_net *net)
 300 {
 301         /* TX flush waits for outstanding DMAs to be done.
 302          * Don't start new DMAs.
 303          */
 304         return !net->tx_flush &&
 305                 net->tx_packets / 64 >= net->tx_zcopy_err;
 306 }
 307
 308 static bool vhost_sock_zcopy(struct socket *sock)
 309 {
 310         return unlikely(experimental_zcopytx) &&
 311                 sock_flag(sock->sk, SOCK_ZEROCOPY);
 312 }
 313
 314 /* In case of DMA done not in order in lower device driver for some reason.
 315  * upend_idx is used to track end of used idx, done_idx is used to track head
 316  * of used idx. Once lower device DMA done contiguously, we will signal KVM
 317  * guest used idx.
 318  */
 319 static void vhost_zerocopy_signal_used(struct vhost_net *net,
 320                                        struct vhost_virtqueue *vq)
 321 {
 322         struct vhost_net_virtqueue *nvq =
 323                 container_of(vq, struct vhost_net_virtqueue, vq);
 324         int i, add;
 325         int j = 0;
 326
 327         for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
 328                 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN)
 329                         vhost_net_tx_err(net);
 330                 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
 331                         vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
 332                         ++j;
 333                 } else
 334                         break;
 335         }
 336         while (j) {
 337                 add = min(UIO_MAXIOV - nvq->done_idx, j);
 338                 vhost_add_used_and_signal_n(vq->dev, vq,
 339                                             &vq->heads[nvq->done_idx], add);
 340                 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV;
 341                 j -= add;
 342         }
 343 }
 344
 345 static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
 346 {
 347         struct vhost_net_ubuf_ref *ubufs = ubuf->ctx;
 348         struct vhost_virtqueue *vq = ubufs->vq;
 349         int cnt;
 350
 351         rcu_read_lock_bh();
 352
 353         /* set len to mark this desc buffers done DMA */
 354         vq->heads[ubuf->desc].len = success ?
 355                 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN;
 356         cnt = vhost_net_ubuf_put(ubufs);
 357
 358         /*
 359          * Trigger polling thread if guest stopped submitting new buffers:
 360          * in this case, the refcount after decrement will eventually reach 1.
 361          * We also trigger polling periodically after each 16 packets
 362          * (the value 16 here is more or less arbitrary, it's tuned to trigger
 363          * less than 10% of times).
 364          */
 365         if (cnt <= 1 || !(cnt % 16))
 366                 vhost_poll_queue(&vq->poll);
 367
 368         rcu_read_unlock_bh();
 369 }
 370
 371 static inline unsigned long busy_clock(void)
 372 {
 373         return local_clock() >> 10;
 374 }
 375
 376 static bool vhost_can_busy_poll(struct vhost_dev *dev,
 377                                 unsigned long endtime)
 378 {
 379         return likely(!need_resched()) &&
 380                likely(!time_after(busy_clock(), endtime)) &&
 381                likely(!signal_pending(current)) &&
 382                !vhost_has_work(dev);
 383 }
 384
 385 static void vhost_net_disable_vq(struct vhost_net *n,
 386                                  struct vhost_virtqueue *vq)
 387 {
 388         struct vhost_net_virtqueue *nvq =
 389                 container_of(vq, struct vhost_net_virtqueue, vq);
 390         struct vhost_poll *poll = n->poll + (nvq - n->vqs);
 391         if (!vq->private_data)
 392                 return;
 393         vhost_poll_stop(poll);
 394 }
 395
 396 static int vhost_net_enable_vq(struct vhost_net *n,
 397                                 struct vhost_virtqueue *vq)
 398 {
 399         struct vhost_net_virtqueue *nvq =
 400                 container_of(vq, struct vhost_net_virtqueue, vq);
 401         struct vhost_poll *poll = n->poll + (nvq - n->vqs);
 402         struct socket *sock;
 403
 404         sock = vq->private_data;
 405         if (!sock)
 406                 return 0;
 407
 408         return vhost_poll_start(poll, sock->file);
 409 }
 410
 411 static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
 412                                     struct vhost_virtqueue *vq,
 413                                     struct iovec iov[], unsigned int iov_size,
 414                                     unsigned int *out_num, unsigned int *in_num)
 415 {
 416         unsigned long uninitialized_var(endtime);
 417         int r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
 418                                   out_num, in_num, NULL, NULL);
 419
 420         if (r == vq->num && vq->busyloop_timeout) {
 421                 preempt_disable();
 422                 endtime = busy_clock() + vq->busyloop_timeout;
 423                 while (vhost_can_busy_poll(vq->dev, endtime) &&
 424                        vhost_vq_avail_empty(vq->dev, vq))
 425                         cpu_relax();
 426                 preempt_enable();
 427                 r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
 428                                       out_num, in_num, NULL, NULL);
 429         }
 430
 431         return r;
 432 }
 433
 434 static bool vhost_exceeds_maxpend(struct vhost_net *net)
 435 {
 436         struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
 437         struct vhost_virtqueue *vq = &nvq->vq;
 438
 439         return (nvq->upend_idx + vq->num - VHOST_MAX_PEND) % UIO_MAXIOV
 440                 == nvq->done_idx;
 441 }
 442
 443 /* Expects to be always run from workqueue - which acts as
 444  * read-size critical section for our kind of RCU. */
 445 static void handle_tx(struct vhost_net *net)
 446 {
 447         struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
 448         struct vhost_virtqueue *vq = &nvq->vq;
 449         unsigned out, in;
 450         int head;
 451         struct msghdr msg = {
 452                 .msg_name = NULL,
 453                 .msg_namelen = 0,
 454                 .msg_control = NULL,
 455                 .msg_controllen = 0,
 456                 .msg_flags = MSG_DONTWAIT,
 457         };
 458         size_t len, total_len = 0;
 459         int err;
 460         size_t hdr_size;
 461         struct socket *sock;
 462         struct vhost_net_ubuf_ref *uninitialized_var(ubufs);
 463         bool zcopy, zcopy_used;
 464
 465         mutex_lock(&vq->mutex);
 466         sock = vq->private_data;
 467         if (!sock)
 468                 goto out;
 469
 470         if (!vq_iotlb_prefetch(vq))
 471                 goto out;
 472
 473         vhost_disable_notify(&net->dev, vq);
 474
 475         hdr_size = nvq->vhost_hlen;
 476         zcopy = nvq->ubufs;
 477
 478         for (;;) {
 479                 /* Release DMAs done buffers first */
 480                 if (zcopy)
 481                         vhost_zerocopy_signal_used(net, vq);
 482
 483                 /* If more outstanding DMAs, queue the work.
 484                  * Handle upend_idx wrap around
 485                  */
 486                 if (unlikely(vhost_exceeds_maxpend(net)))
 487                         break;
 488
 489                 head = vhost_net_tx_get_vq_desc(net, vq, vq->iov,
 490                                                 ARRAY_SIZE(vq->iov),
 491                                                 &out, &in);
 492                 /* On error, stop handling until the next kick. */
 493                 if (unlikely(head < 0))
 494                         break;
 495                 /* Nothing new?  Wait for eventfd to tell us they refilled. */
 496                 if (head == vq->num) {
 497                         if (unlikely(vhost_enable_notify(&net->dev, vq))) {
 498                                 vhost_disable_notify(&net->dev, vq);
 499                                 continue;
 500                         }
 501                         break;
 502                 }
 503                 if (in) {
 504                         vq_err(vq, "Unexpected descriptor format for TX: "
 505                                "out %d, int %d\n", out, in);
 506                         break;
 507                 }
 508                 /* Skip header. TODO: support TSO. */
 509                 len = iov_length(vq->iov, out);
 510                 iov_iter_init(&msg.msg_iter, WRITE, vq->iov, out, len);
 511                 iov_iter_advance(&msg.msg_iter, hdr_size);
 512                 /* Sanity check */
 513                 if (!msg_data_left(&msg)) {
 514                         vq_err(vq, "Unexpected header len for TX: "
 515                                "%zd expected %zd\n",
 516                                len, hdr_size);
 517                         break;
 518                 }
 519                 len = msg_data_left(&msg);
 520
 521                 zcopy_used = zcopy && len >= VHOST_GOODCOPY_LEN
 522                                    && (nvq->upend_idx + 1) % UIO_MAXIOV !=
 523                                       nvq->done_idx
 524                                    && vhost_net_tx_select_zcopy(net);
 525
 526                 /* use msg_control to pass vhost zerocopy ubuf info to skb */
 527                 if (zcopy_used) {
 528                         struct ubuf_info *ubuf;
 529                         ubuf = nvq->ubuf_info + nvq->upend_idx;
 530
 531                         vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head);
 532                         vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS;
 533                         ubuf->callback = vhost_zerocopy_callback;
 534                         ubuf->ctx = nvq->ubufs;
 535                         ubuf->desc = nvq->upend_idx;
 536                         atomic_set(&ubuf->refcnt, 1);
 537                         msg.msg_control = ubuf;
 538                         msg.msg_controllen = sizeof(ubuf);
 539                         ubufs = nvq->ubufs;
 540                         atomic_inc(&ubufs->refcount);
 541                         nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
 542                 } else {
 543                         msg.msg_control = NULL;
 544                         ubufs = NULL;
 545                 }
 546
 547                 total_len += len;
 548                 if (total_len < VHOST_NET_WEIGHT &&
 549                     !vhost_vq_avail_empty(&net->dev, vq) &&
 550                     likely(!vhost_exceeds_maxpend(net))) {
 551                         msg.msg_flags |= MSG_MORE;
 552                 } else {
 553                         msg.msg_flags &= ~MSG_MORE;
 554                 }
 555
 556                 /* TODO: Check specific error and bomb out unless ENOBUFS? */
 557                 err = sock->ops->sendmsg(sock, &msg, len);
 558                 if (unlikely(err < 0)) {
 559                         if (zcopy_used) {
 560                                 vhost_net_ubuf_put(ubufs);
 561                                 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
 562                                         % UIO_MAXIOV;
 563                         }
 564                         vhost_discard_vq_desc(vq, 1);
 565                         break;
 566                 }
 567                 if (err != len)
 568                         pr_debug("Truncated TX packet: "
 569                                  " len %d != %zd\n", err, len);
 570                 if (!zcopy_used)
 571                         vhost_add_used_and_signal(&net->dev, vq, head, 0);
 572                 else
 573                         vhost_zerocopy_signal_used(net, vq);
 574                 vhost_net_tx_packet(net);
 575                 if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
 576                         vhost_poll_queue(&vq->poll);
 577                         break;
 578                 }
 579         }
 580 out:
 581         mutex_unlock(&vq->mutex);
 582 }
 583
 584 static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk)
 585 {
 586         struct sk_buff *head;
 587         int len = 0;
 588         unsigned long flags;
 589
 590         if (rvq->rx_array)
 591                 return vhost_net_buf_peek(rvq);
 592
 593         spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
 594         head = skb_peek(&sk->sk_receive_queue);
 595         if (likely(head)) {
 596                 len = head->len;
 597                 if (skb_vlan_tag_present(head))
 598                         len += VLAN_HLEN;
 599         }
 600
 601         spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags);
 602         return len;
 603 }
 604
 605 static int sk_has_rx_data(struct sock *sk)
 606 {
 607         struct socket *sock = sk->sk_socket;
 608
 609         if (sock->ops->peek_len)
 610                 return sock->ops->peek_len(sock);
 611
 612         return skb_queue_empty(&sk->sk_receive_queue);
 613 }
 614
 615 static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk)
 616 {
 617         struct vhost_net_virtqueue *rvq = &net->vqs[VHOST_NET_VQ_RX];
 618         struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
 619         struct vhost_virtqueue *vq = &nvq->vq;
 620         unsigned long uninitialized_var(endtime);
 621         int len = peek_head_len(rvq, sk);
 622
 623         if (!len && vq->busyloop_timeout) {
 624                 /* Both tx vq and rx socket were polled here */
 625                 mutex_lock(&vq->mutex);
 626                 vhost_disable_notify(&net->dev, vq);
 627
 628                 preempt_disable();
 629                 endtime = busy_clock() + vq->busyloop_timeout;
 630
 631                 while (vhost_can_busy_poll(&net->dev, endtime) &&
 632                        !sk_has_rx_data(sk) &&
 633                        vhost_vq_avail_empty(&net->dev, vq))
 634                         cpu_relax();
 635
 636                 preempt_enable();
 637
 638                 if (vhost_enable_notify(&net->dev, vq))
 639                         vhost_poll_queue(&vq->poll);
 640                 mutex_unlock(&vq->mutex);
 641
 642                 len = peek_head_len(rvq, sk);
 643         }
 644
 645         return len;
 646 }
 647
 648 /* This is a multi-buffer version of vhost_get_desc, that works if
 649  *      vq has read descriptors only.
 650  * @vq          - the relevant virtqueue
 651  * @datalen     - data length we'll be reading
 652  * @iovcount    - returned count of io vectors we fill
 653  * @log         - vhost log
 654  * @log_num     - log offset
 655  * @quota       - headcount quota, 1 for big buffer
 656  *      returns number of buffer heads allocated, negative on error
 657  */
 658 static int get_rx_bufs(struct vhost_virtqueue *vq,
 659                        struct vring_used_elem *heads,
 660                        int datalen,
 661                        unsigned *iovcount,
 662                        struct vhost_log *log,
 663                        unsigned *log_num,
 664                        unsigned int quota)
 665 {
 666         unsigned int out, in;
 667         int seg = 0;
 668         int headcount = 0;
 669         unsigned d;
 670         int r, nlogs = 0;
 671         /* len is always initialized before use since we are always called with
 672          * datalen > 0.
 673          */
 674         u32 uninitialized_var(len);
 675
 676         while (datalen > 0 && headcount < quota) {
 677                 if (unlikely(seg >= UIO_MAXIOV)) {
 678                         r = -ENOBUFS;
 679                         goto err;
 680                 }
 681                 r = vhost_get_vq_desc(vq, vq->iov + seg,
 682                                       ARRAY_SIZE(vq->iov) - seg, &out,
 683                                       &in, log, log_num);
 684                 if (unlikely(r < 0))
 685                         goto err;
 686
 687                 d = r;
 688                 if (d == vq->num) {
 689                         r = 0;
 690                         goto err;
 691                 }
 692                 if (unlikely(out || in <= 0)) {
 693                         vq_err(vq, "unexpected descriptor format for RX: "
 694                                 "out %d, in %d\n", out, in);
 695                         r = -EINVAL;
 696                         goto err;
 697                 }
 698                 if (unlikely(log)) {
 699                         nlogs += *log_num;
 700                         log += *log_num;
 701                 }
 702                 heads[headcount].id = cpu_to_vhost32(vq, d);
 703                 len = iov_length(vq->iov + seg, in);
 704                 heads[headcount].len = cpu_to_vhost32(vq, len);
 705                 datalen -= len;
 706                 ++headcount;
 707                 seg += in;
 708         }
 709         heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
 710         *iovcount = seg;
 711         if (unlikely(log))
 712                 *log_num = nlogs;
 713
 714         /* Detect overrun */
 715         if (unlikely(datalen > 0)) {
 716                 r = UIO_MAXIOV + 1;
 717                 goto err;
 718         }
 719         return headcount;
 720 err:
 721         vhost_discard_vq_desc(vq, headcount);
 722         return r;
 723 }
 724
 725 /* Expects to be always run from workqueue - which acts as
 726  * read-size critical section for our kind of RCU. */
 727 static void handle_rx(struct vhost_net *net)
 728 {
 729         struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX];
 730         struct vhost_virtqueue *vq = &nvq->vq;
 731         unsigned uninitialized_var(in), log;
 732         struct vhost_log *vq_log;
 733         struct msghdr msg = {
 734                 .msg_name = NULL,
 735                 .msg_namelen = 0,
 736                 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
 737                 .msg_controllen = 0,
 738                 .msg_flags = MSG_DONTWAIT,
 739         };
 740         struct virtio_net_hdr hdr = {
 741                 .flags = 0,
 742                 .gso_type = VIRTIO_NET_HDR_GSO_NONE
 743         };
 744         size_t total_len = 0;
 745         int err, mergeable;
 746         s16 headcount;
 747         size_t vhost_hlen, sock_hlen;
 748         size_t vhost_len, sock_len;
 749         struct socket *sock;
 750         struct iov_iter fixup;
 751         __virtio16 num_buffers;
 752
 753         mutex_lock(&vq->mutex);
 754         sock = vq->private_data;
 755         if (!sock)
 756                 goto out;
 757
 758         if (!vq_iotlb_prefetch(vq))
 759                 goto out;
 760
 761         vhost_disable_notify(&net->dev, vq);
 762         vhost_net_disable_vq(net, vq);
 763
 764         vhost_hlen = nvq->vhost_hlen;
 765         sock_hlen = nvq->sock_hlen;
 766
 767         vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ?
 768                 vq->log : NULL;
 769         mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF);
 770
 771         while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk))) {
 772                 sock_len += sock_hlen;
 773                 vhost_len = sock_len + vhost_hlen;
 774                 headcount = get_rx_bufs(vq, vq->heads, vhost_len,
 775                                         &in, vq_log, &log,
 776                                         likely(mergeable) ? UIO_MAXIOV : 1);
 777                 /* On error, stop handling until the next kick. */
 778                 if (unlikely(headcount < 0))
 779                         goto out;
 780                 if (nvq->rx_array)
 781                         msg.msg_control = vhost_net_buf_consume(&nvq->rxq);
 782                 /* On overrun, truncate and discard */
 783                 if (unlikely(headcount > UIO_MAXIOV)) {
 784                         iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1);
 785                         err = sock->ops->recvmsg(sock, &msg,
 786                                                  1, MSG_DONTWAIT | MSG_TRUNC);
 787                         pr_debug("Discarded rx packet: len %zd\n", sock_len);
 788                         continue;
 789                 }
 790                 /* OK, now we need to know about added descriptors. */
 791                 if (!headcount) {
 792                         if (unlikely(vhost_enable_notify(&net->dev, vq))) {
 793                                 /* They have slipped one in as we were
 794                                  * doing that: check again. */
 795                                 vhost_disable_notify(&net->dev, vq);
 796                                 continue;
 797                         }
 798                         /* Nothing new?  Wait for eventfd to tell us
 799                          * they refilled. */
 800                         goto out;
 801                 }
 802                 /* We don't need to be notified again. */
 803                 iov_iter_init(&msg.msg_iter, READ, vq->iov, in, vhost_len);
 804                 fixup = msg.msg_iter;
 805                 if (unlikely((vhost_hlen))) {
 806                         /* We will supply the header ourselves
 807                          * TODO: support TSO.
 808                          */
 809                         iov_iter_advance(&msg.msg_iter, vhost_hlen);
 810                 }
 811                 err = sock->ops->recvmsg(sock, &msg,
 812                                          sock_len, MSG_DONTWAIT | MSG_TRUNC);
 813                 /* Userspace might have consumed the packet meanwhile:
 814                  * it's not supposed to do this usually, but might be hard
 815                  * to prevent. Discard data we got (if any) and keep going. */
 816                 if (unlikely(err != sock_len)) {
 817                         pr_debug("Discarded rx packet: "
 818                                  " len %d, expected %zd\n", err, sock_len);
 819                         vhost_discard_vq_desc(vq, headcount);
 820                         continue;
 821                 }
 822                 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
 823                 if (unlikely(vhost_hlen)) {
 824                         if (copy_to_iter(&hdr, sizeof(hdr),
 825                                          &fixup) != sizeof(hdr)) {
 826                                 vq_err(vq, "Unable to write vnet_hdr "
 827                                        "at addr %p\n", vq->iov->iov_base);
 828                                 goto out;
 829                         }
 830                 } else {
 831                         /* Header came from socket; we'll need to patch
 832                          * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF
 833                          */
 834                         iov_iter_advance(&fixup, sizeof(hdr));
 835                 }
 836                 /* TODO: Should check and handle checksum. */
 837
 838                 num_buffers = cpu_to_vhost16(vq, headcount);
 839                 if (likely(mergeable) &&
 840                     copy_to_iter(&num_buffers, sizeof num_buffers,
 841                                  &fixup) != sizeof num_buffers) {
 842                         vq_err(vq, "Failed num_buffers write");
 843                         vhost_discard_vq_desc(vq, headcount);
 844                         goto out;
 845                 }
 846                 vhost_add_used_and_signal_n(&net->dev, vq, vq->heads,
 847                                             headcount);
 848                 if (unlikely(vq_log))
 849                         vhost_log_write(vq, vq_log, log, vhost_len);
 850                 total_len += vhost_len;
 851                 if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
 852                         vhost_poll_queue(&vq->poll);
 853                         goto out;
 854                 }
 855         }
 856         vhost_net_enable_vq(net, vq);
 857 out:
 858         mutex_unlock(&vq->mutex);
 859 }
 860
 861 static void handle_tx_kick(struct vhost_work *work)
 862 {
 863         struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
 864                                                   poll.work);
 865         struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
 866
 867         handle_tx(net);
 868 }
 869
 870 static void handle_rx_kick(struct vhost_work *work)
 871 {
 872         struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
 873                                                   poll.work);
 874         struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
 875
 876         handle_rx(net);
 877 }
 878
 879 static void handle_tx_net(struct vhost_work *work)
 880 {
 881         struct vhost_net *net = container_of(work, struct vhost_net,
 882                                              poll[VHOST_NET_VQ_TX].work);
 883         handle_tx(net);
 884 }
 885
 886 static void handle_rx_net(struct vhost_work *work)
 887 {
 888         struct vhost_net *net = container_of(work, struct vhost_net,
 889                                              poll[VHOST_NET_VQ_RX].work);
 890         handle_rx(net);
 891 }
 892
 893 static int vhost_net_open(struct inode *inode, struct file *f)
 894 {
 895         struct vhost_net *n;
 896         struct vhost_dev *dev;
 897         struct vhost_virtqueue **vqs;
 898         struct sk_buff **queue;
 899         int i;
 900
 901         n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
 902         if (!n)
 903                 return -ENOMEM;
 904         vqs = kmalloc(VHOST_NET_VQ_MAX * sizeof(*vqs), GFP_KERNEL);
 905         if (!vqs) {
 906                 kvfree(n);
 907                 return -ENOMEM;
 908         }
 909
 910         queue = kmalloc_array(VHOST_RX_BATCH, sizeof(struct sk_buff *),
 911                               GFP_KERNEL);
 912         if (!queue) {
 913                 kfree(vqs);
 914                 kvfree(n);
 915                 return -ENOMEM;
 916         }
 917         n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue;
 918
 919         dev = &n->dev;
 920         vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq;
 921         vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq;
 922         n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick;
 923         n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick;
 924         for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
 925                 n->vqs[i].ubufs = NULL;
 926                 n->vqs[i].ubuf_info = NULL;
 927                 n->vqs[i].upend_idx = 0;
 928                 n->vqs[i].done_idx = 0;
 929                 n->vqs[i].vhost_hlen = 0;
 930                 n->vqs[i].sock_hlen = 0;
 931                 vhost_net_buf_init(&n->vqs[i].rxq);
 932         }
 933         vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX);
 934
 935         vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev);
 936         vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev);
 937
 938         f->private_data = n;
 939
 940         return 0;
 941 }
 942
 943 static struct socket *vhost_net_stop_vq(struct vhost_net *n,
 944                                         struct vhost_virtqueue *vq)
 945 {
 946         struct socket *sock;
 947         struct vhost_net_virtqueue *nvq =
 948                 container_of(vq, struct vhost_net_virtqueue, vq);
 949
 950         mutex_lock(&vq->mutex);
 951         sock = vq->private_data;
 952         vhost_net_disable_vq(n, vq);
 953         vq->private_data = NULL;
 954         vhost_net_buf_unproduce(nvq);
 955         mutex_unlock(&vq->mutex);
 956         return sock;
 957 }
 958
 959 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
 960                            struct socket **rx_sock)
 961 {
 962         *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq);
 963         *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq);
 964 }
 965
 966 static void vhost_net_flush_vq(struct vhost_net *n, int index)
 967 {
 968         vhost_poll_flush(n->poll + index);
 969         vhost_poll_flush(&n->vqs[index].vq.poll);
 970 }
 971
 972 static void vhost_net_flush(struct vhost_net *n)
 973 {
 974         vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
 975         vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
 976         if (n->vqs[VHOST_NET_VQ_TX].ubufs) {
 977                 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
 978                 n->tx_flush = true;
 979                 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
 980                 /* Wait for all lower device DMAs done. */
 981                 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs);
 982                 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
 983                 n->tx_flush = false;
 984                 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1);
 985                 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
 986         }
 987 }
 988
 989 static int vhost_net_release(struct inode *inode, struct file *f)
 990 {
 991         struct vhost_net *n = f->private_data;
 992         struct socket *tx_sock;
 993         struct socket *rx_sock;
 994
 995         vhost_net_stop(n, &tx_sock, &rx_sock);
 996         vhost_net_flush(n);
 997         vhost_dev_stop(&n->dev);
 998         vhost_dev_cleanup(&n->dev, false);
 999         vhost_net_vq_reset(n);
1000         if (tx_sock)
1001                 sockfd_put(tx_sock);
1002         if (rx_sock)
1003                 sockfd_put(rx_sock);
1004         /* Make sure no callbacks are outstanding */
1005         synchronize_rcu_bh();
1006         /* We do an extra flush before freeing memory,
1007          * since jobs can re-queue themselves. */
1008         vhost_net_flush(n);
1009         kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue);
1010         kfree(n->dev.vqs);
1011         kvfree(n);
1012         return 0;
1013 }
1014
1015 static struct socket *get_raw_socket(int fd)
1016 {
1017         struct {
1018                 struct sockaddr_ll sa;
1019                 char  buf[MAX_ADDR_LEN];
1020         } uaddr;
1021         int uaddr_len = sizeof uaddr, r;
1022         struct socket *sock = sockfd_lookup(fd, &r);
1023
1024         if (!sock)
1025                 return ERR_PTR(-ENOTSOCK);
1026
1027         /* Parameter checking */
1028         if (sock->sk->sk_type != SOCK_RAW) {
1029                 r = -ESOCKTNOSUPPORT;
1030                 goto err;
1031         }
1032
1033         r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa,
1034                                &uaddr_len, 0);
1035         if (r)
1036                 goto err;
1037
1038         if (uaddr.sa.sll_family != AF_PACKET) {
1039                 r = -EPFNOSUPPORT;
1040                 goto err;
1041         }
1042         return sock;
1043 err:
1044         sockfd_put(sock);
1045         return ERR_PTR(r);
1046 }
1047
1048 static struct skb_array *get_tap_skb_array(int fd)
1049 {
1050         struct skb_array *array;
1051         struct file *file = fget(fd);
1052
1053         if (!file)
1054                 return NULL;
1055         array = tun_get_skb_array(file);
1056         if (!IS_ERR(array))
1057                 goto out;
1058         array = tap_get_skb_array(file);
1059         if (!IS_ERR(array))
1060                 goto out;
1061         array = NULL;
1062 out:
1063         fput(file);
1064         return array;
1065 }
1066
1067 static struct socket *get_tap_socket(int fd)
1068 {
1069         struct file *file = fget(fd);
1070         struct socket *sock;
1071
1072         if (!file)
1073                 return ERR_PTR(-EBADF);
1074         sock = tun_get_socket(file);
1075         if (!IS_ERR(sock))
1076                 return sock;
1077         sock = tap_get_socket(file);
1078         if (IS_ERR(sock))
1079                 fput(file);
1080         return sock;
1081 }
1082
1083 static struct socket *get_socket(int fd)
1084 {
1085         struct socket *sock;
1086
1087         /* special case to disable backend */
1088         if (fd == -1)
1089                 return NULL;
1090         sock = get_raw_socket(fd);
1091         if (!IS_ERR(sock))
1092                 return sock;
1093         sock = get_tap_socket(fd);
1094         if (!IS_ERR(sock))
1095                 return sock;
1096         return ERR_PTR(-ENOTSOCK);
1097 }
1098
1099 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
1100 {
1101         struct socket *sock, *oldsock;
1102         struct vhost_virtqueue *vq;
1103         struct vhost_net_virtqueue *nvq;
1104         struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL;
1105         int r;
1106
1107         mutex_lock(&n->dev.mutex);
1108         r = vhost_dev_check_owner(&n->dev);
1109         if (r)
1110                 goto err;
1111
1112         if (index >= VHOST_NET_VQ_MAX) {
1113                 r = -ENOBUFS;
1114                 goto err;
1115         }
1116         vq = &n->vqs[index].vq;
1117         nvq = &n->vqs[index];
1118         mutex_lock(&vq->mutex);
1119
1120         /* Verify that ring has been setup correctly. */
1121         if (!vhost_vq_access_ok(vq)) {
1122                 r = -EFAULT;
1123                 goto err_vq;
1124         }
1125         sock = get_socket(fd);
1126         if (IS_ERR(sock)) {
1127                 r = PTR_ERR(sock);
1128                 goto err_vq;
1129         }
1130
1131         /* start polling new socket */
1132         oldsock = vq->private_data;
1133         if (sock != oldsock) {
1134                 ubufs = vhost_net_ubuf_alloc(vq,
1135                                              sock && vhost_sock_zcopy(sock));
1136                 if (IS_ERR(ubufs)) {
1137                         r = PTR_ERR(ubufs);
1138                         goto err_ubufs;
1139                 }
1140
1141                 vhost_net_disable_vq(n, vq);
1142                 vq->private_data = sock;
1143                 vhost_net_buf_unproduce(nvq);
1144                 if (index == VHOST_NET_VQ_RX)
1145                         nvq->rx_array = get_tap_skb_array(fd);
1146                 r = vhost_vq_init_access(vq);
1147                 if (r)
1148                         goto err_used;
1149                 r = vhost_net_enable_vq(n, vq);
1150                 if (r)
1151                         goto err_used;
1152
1153                 oldubufs = nvq->ubufs;
1154                 nvq->ubufs = ubufs;
1155
1156                 n->tx_packets = 0;
1157                 n->tx_zcopy_err = 0;
1158                 n->tx_flush = false;
1159         }
1160
1161         mutex_unlock(&vq->mutex);
1162
1163         if (oldubufs) {
1164                 vhost_net_ubuf_put_wait_and_free(oldubufs);
1165                 mutex_lock(&vq->mutex);
1166                 vhost_zerocopy_signal_used(n, vq);
1167                 mutex_unlock(&vq->mutex);
1168         }
1169
1170         if (oldsock) {
1171                 vhost_net_flush_vq(n, index);
1172                 sockfd_put(oldsock);
1173         }
1174
1175         mutex_unlock(&n->dev.mutex);
1176         return 0;
1177
1178 err_used:
1179         vq->private_data = oldsock;
1180         vhost_net_enable_vq(n, vq);
1181         if (ubufs)
1182                 vhost_net_ubuf_put_wait_and_free(ubufs);
1183 err_ubufs:
1184         sockfd_put(sock);
1185 err_vq:
1186         mutex_unlock(&vq->mutex);
1187 err:
1188         mutex_unlock(&n->dev.mutex);
1189         return r;
1190 }
1191
1192 static long vhost_net_reset_owner(struct vhost_net *n)
1193 {
1194         struct socket *tx_sock = NULL;
1195         struct socket *rx_sock = NULL;
1196         long err;
1197         struct vhost_umem *umem;
1198
1199         mutex_lock(&n->dev.mutex);
1200         err = vhost_dev_check_owner(&n->dev);
1201         if (err)
1202                 goto done;
1203         umem = vhost_dev_reset_owner_prepare();
1204         if (!umem) {
1205                 err = -ENOMEM;
1206                 goto done;
1207         }
1208         vhost_net_stop(n, &tx_sock, &rx_sock);
1209         vhost_net_flush(n);
1210         vhost_dev_reset_owner(&n->dev, umem);
1211         vhost_net_vq_reset(n);
1212 done:
1213         mutex_unlock(&n->dev.mutex);
1214         if (tx_sock)
1215                 sockfd_put(tx_sock);
1216         if (rx_sock)
1217                 sockfd_put(rx_sock);
1218         return err;
1219 }
1220
1221 static int vhost_net_set_features(struct vhost_net *n, u64 features)
1222 {
1223         size_t vhost_hlen, sock_hlen, hdr_len;
1224         int i;
1225
1226         hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
1227                                (1ULL << VIRTIO_F_VERSION_1))) ?
1228                         sizeof(struct virtio_net_hdr_mrg_rxbuf) :
1229                         sizeof(struct virtio_net_hdr);
1230         if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
1231                 /* vhost provides vnet_hdr */
1232                 vhost_hlen = hdr_len;
1233                 sock_hlen = 0;
1234         } else {
1235                 /* socket provides vnet_hdr */
1236                 vhost_hlen = 0;
1237                 sock_hlen = hdr_len;
1238         }
1239         mutex_lock(&n->dev.mutex);
1240         if ((features & (1 << VHOST_F_LOG_ALL)) &&
1241             !vhost_log_access_ok(&n->dev))
1242                 goto out_unlock;
1243
1244         if ((features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))) {
1245                 if (vhost_init_device_iotlb(&n->dev, true))
1246                         goto out_unlock;
1247         }
1248
1249         for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1250                 mutex_lock(&n->vqs[i].vq.mutex);
1251                 n->vqs[i].vq.acked_features = features;
1252                 n->vqs[i].vhost_hlen = vhost_hlen;
1253                 n->vqs[i].sock_hlen = sock_hlen;
1254                 mutex_unlock(&n->vqs[i].vq.mutex);
1255         }
1256         mutex_unlock(&n->dev.mutex);
1257         return 0;
1258
1259 out_unlock:
1260         mutex_unlock(&n->dev.mutex);
1261         return -EFAULT;
1262 }
1263
1264 static long vhost_net_set_owner(struct vhost_net *n)
1265 {
1266         int r;
1267
1268         mutex_lock(&n->dev.mutex);
1269         if (vhost_dev_has_owner(&n->dev)) {
1270                 r = -EBUSY;
1271                 goto out;
1272         }
1273         r = vhost_net_set_ubuf_info(n);
1274         if (r)
1275                 goto out;
1276         r = vhost_dev_set_owner(&n->dev);
1277         if (r)
1278                 vhost_net_clear_ubuf_info(n);
1279         vhost_net_flush(n);
1280 out:
1281         mutex_unlock(&n->dev.mutex);
1282         return r;
1283 }
1284
1285 static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
1286                             unsigned long arg)
1287 {
1288         struct vhost_net *n = f->private_data;
1289         void __user *argp = (void __user *)arg;
1290         u64 __user *featurep = argp;
1291         struct vhost_vring_file backend;
1292         u64 features;
1293         int r;
1294
1295         switch (ioctl) {
1296         case VHOST_NET_SET_BACKEND:
1297                 if (copy_from_user(&backend, argp, sizeof backend))
1298                         return -EFAULT;
1299                 return vhost_net_set_backend(n, backend.index, backend.fd);
1300         case VHOST_GET_FEATURES:
1301                 features = VHOST_NET_FEATURES;
1302                 if (copy_to_user(featurep, &features, sizeof features))
1303                         return -EFAULT;
1304                 return 0;
1305         case VHOST_SET_FEATURES:
1306                 if (copy_from_user(&features, featurep, sizeof features))
1307                         return -EFAULT;
1308                 if (features & ~VHOST_NET_FEATURES)
1309                         return -EOPNOTSUPP;
1310                 return vhost_net_set_features(n, features);
1311         case VHOST_RESET_OWNER:
1312                 return vhost_net_reset_owner(n);
1313         case VHOST_SET_OWNER:
1314                 return vhost_net_set_owner(n);
1315         default:
1316                 mutex_lock(&n->dev.mutex);
1317                 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
1318                 if (r == -ENOIOCTLCMD)
1319                         r = vhost_vring_ioctl(&n->dev, ioctl, argp);
1320                 else
1321                         vhost_net_flush(n);
1322                 mutex_unlock(&n->dev.mutex);
1323                 return r;
1324         }
1325 }
1326
1327 #ifdef CONFIG_COMPAT
1328 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl,
1329                                    unsigned long arg)
1330 {
1331         return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
1332 }
1333 #endif
1334
1335 static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1336 {
1337         struct file *file = iocb->ki_filp;
1338         struct vhost_net *n = file->private_data;
1339         struct vhost_dev *dev = &n->dev;
1340         int noblock = file->f_flags & O_NONBLOCK;
1341
1342         return vhost_chr_read_iter(dev, to, noblock);
1343 }
1344
1345 static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb,
1346                                         struct iov_iter *from)
1347 {
1348         struct file *file = iocb->ki_filp;
1349         struct vhost_net *n = file->private_data;
1350         struct vhost_dev *dev = &n->dev;
1351
1352         return vhost_chr_write_iter(dev, from);
1353 }
1354
1355 static unsigned int vhost_net_chr_poll(struct file *file, poll_table *wait)
1356 {
1357         struct vhost_net *n = file->private_data;
1358         struct vhost_dev *dev = &n->dev;
1359
1360         return vhost_chr_poll(file, dev, wait);
1361 }
1362
1363 static const struct file_operations vhost_net_fops = {
1364         .owner          = THIS_MODULE,
1365         .release        = vhost_net_release,
1366         .read_iter      = vhost_net_chr_read_iter,
1367         .write_iter     = vhost_net_chr_write_iter,
1368         .poll           = vhost_net_chr_poll,
1369         .unlocked_ioctl = vhost_net_ioctl,
1370 #ifdef CONFIG_COMPAT
1371         .compat_ioctl   = vhost_net_compat_ioctl,
1372 #endif
1373         .open           = vhost_net_open,
1374         .llseek         = noop_llseek,
1375 };
1376
1377 static struct miscdevice vhost_net_misc = {
1378         .minor = VHOST_NET_MINOR,
1379         .name = "vhost-net",
1380         .fops = &vhost_net_fops,
1381 };
1382
1383 static int vhost_net_init(void)
1384 {
1385         if (experimental_zcopytx)
1386                 vhost_net_enable_zcopy(VHOST_NET_VQ_TX);
1387         return misc_register(&vhost_net_misc);
1388 }
1389 module_init(vhost_net_init);
1390
1391 static void vhost_net_exit(void)
1392 {
1393         misc_deregister(&vhost_net_misc);
1394 }
1395 module_exit(vhost_net_exit);
1396
1397 MODULE_VERSION("0.0.1");
1398 MODULE_LICENSE("GPL v2");
1399 MODULE_AUTHOR("Michael S. Tsirkin");
1400 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1401 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
1402 MODULE_ALIAS("devname:vhost-net");