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 36enum { 37 VHOST_NET_VQ_RX = 0, 38 VHOST_NET_VQ_TX = 1, 39 VHOST_NET_VQ_MAX = 2, 40}; 41 42enum vhost_net_poll_state { 43 VHOST_NET_POLL_DISABLED = 0, 44 VHOST_NET_POLL_STARTED = 1, 45 VHOST_NET_POLL_STOPPED = 2, 46}; 47 48struct 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. */ 59static 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/* Copy iovec entries for len bytes from iovec. */ 78static void copy_iovec_hdr(const struct iovec *from, struct iovec *to, 79 size_t len, int iovcount) 80{ 81 int seg = 0; 82 size_t size; 83 while (len && seg < iovcount) { 84 size = min(from->iov_len, len); 85 to->iov_base = from->iov_base; 86 to->iov_len = size; 87 len -= size; 88 ++from; 89 ++to; 90 ++seg; 91 } 92} 93 94/* Caller must have TX VQ lock */ 95static void tx_poll_stop(struct vhost_net *net) 96{ 97 if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED)) 98 return; 99 vhost_poll_stop(net->poll + VHOST_NET_VQ_TX); 100 net->tx_poll_state = VHOST_NET_POLL_STOPPED; 101} 102 103/* Caller must have TX VQ lock */ 104static void tx_poll_start(struct vhost_net *net, struct socket *sock) 105{ 106 if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED)) 107 return; 108 vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file); 109 net->tx_poll_state = VHOST_NET_POLL_STARTED; 110} 111 112/* Expects to be always run from workqueue - which acts as 113 * read-size critical section for our kind of RCU. */ 114static void handle_tx(struct vhost_net *net) 115{ 116 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX]; 117 unsigned out, in, s; 118 int head; 119 struct msghdr msg = { 120 .msg_name = NULL, 121 .msg_namelen = 0, 122 .msg_control = NULL, 123 .msg_controllen = 0, 124 .msg_iov = vq->iov, 125 .msg_flags = MSG_DONTWAIT, 126 }; 127 size_t len, total_len = 0; 128 int err, wmem; 129 size_t hdr_size; 130 struct socket *sock = rcu_dereference(vq->private_data); 131 if (!sock) 132 return; 133 134 wmem = atomic_read(&sock->sk->sk_wmem_alloc); 135 if (wmem >= sock->sk->sk_sndbuf) { 136 mutex_lock(&vq->mutex); 137 tx_poll_start(net, sock); 138 mutex_unlock(&vq->mutex); 139 return; 140 } 141 142 use_mm(net->dev.mm); 143 mutex_lock(&vq->mutex); 144 vhost_disable_notify(vq); 145 146 if (wmem < sock->sk->sk_sndbuf / 2) 147 tx_poll_stop(net); 148 hdr_size = vq->vhost_hlen; 149 150 for (;;) { 151 head = vhost_get_vq_desc(&net->dev, vq, vq->iov, 152 ARRAY_SIZE(vq->iov), 153 &out, &in, 154 NULL, NULL); 155 /* On error, stop handling until the next kick. */ 156 if (unlikely(head < 0)) 157 break; 158 /* Nothing new? Wait for eventfd to tell us they refilled. */ 159 if (head == vq->num) { 160 wmem = atomic_read(&sock->sk->sk_wmem_alloc); 161 if (wmem >= sock->sk->sk_sndbuf * 3 / 4) { 162 tx_poll_start(net, sock); 163 set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); 164 break; 165 } 166 if (unlikely(vhost_enable_notify(vq))) { 167 vhost_disable_notify(vq); 168 continue; 169 } 170 break; 171 } 172 if (in) { 173 vq_err(vq, "Unexpected descriptor format for TX: " 174 "out %d, int %d\n", out, in); 175 break; 176 } 177 /* Skip header. TODO: support TSO. */ 178 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out); 179 msg.msg_iovlen = out; 180 len = iov_length(vq->iov, out); 181 /* Sanity check */ 182 if (!len) { 183 vq_err(vq, "Unexpected header len for TX: " 184 "%zd expected %zd\n", 185 iov_length(vq->hdr, s), hdr_size); 186 break; 187 } 188 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 189 err = sock->ops->sendmsg(NULL, sock, &msg, len); 190 if (unlikely(err < 0)) { 191 vhost_discard_vq_desc(vq, 1); 192 tx_poll_start(net, sock); 193 break; 194 } 195 if (err != len) 196 pr_debug("Truncated TX packet: " 197 " len %d != %zd\n", err, len); 198 vhost_add_used_and_signal(&net->dev, vq, head, 0); 199 total_len += len; 200 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 201 vhost_poll_queue(&vq->poll); 202 break; 203 } 204 } 205 206 mutex_unlock(&vq->mutex); 207 unuse_mm(net->dev.mm); 208} 209 210static int peek_head_len(struct sock *sk) 211{ 212 struct sk_buff *head; 213 int len = 0; 214 215 lock_sock(sk); 216 head = skb_peek(&sk->sk_receive_queue); 217 if (head) 218 len = head->len; 219 release_sock(sk); 220 return len; 221} 222 223/* This is a multi-buffer version of vhost_get_desc, that works if 224 * vq has read descriptors only. 225 * @vq - the relevant virtqueue 226 * @datalen - data length we'll be reading 227 * @iovcount - returned count of io vectors we fill 228 * @log - vhost log 229 * @log_num - log offset 230 * returns number of buffer heads allocated, negative on error 231 */ 232static int get_rx_bufs(struct vhost_virtqueue *vq, 233 struct vring_used_elem *heads, 234 int datalen, 235 unsigned *iovcount, 236 struct vhost_log *log, 237 unsigned *log_num) 238{ 239 unsigned int out, in; 240 int seg = 0; 241 int headcount = 0; 242 unsigned d; 243 int r, nlogs = 0; 244 245 while (datalen > 0) { 246 if (unlikely(seg >= VHOST_NET_MAX_SG)) { 247 r = -ENOBUFS; 248 goto err; 249 } 250 d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg, 251 ARRAY_SIZE(vq->iov) - seg, &out, 252 &in, log, log_num); 253 if (d == vq->num) { 254 r = 0; 255 goto err; 256 } 257 if (unlikely(out || in <= 0)) { 258 vq_err(vq, "unexpected descriptor format for RX: " 259 "out %d, in %d\n", out, in); 260 r = -EINVAL; 261 goto err; 262 } 263 if (unlikely(log)) { 264 nlogs += *log_num; 265 log += *log_num; 266 } 267 heads[headcount].id = d; 268 heads[headcount].len = iov_length(vq->iov + seg, in); 269 datalen -= heads[headcount].len; 270 ++headcount; 271 seg += in; 272 } 273 heads[headcount - 1].len += datalen; 274 *iovcount = seg; 275 if (unlikely(log)) 276 *log_num = nlogs; 277 return headcount; 278err: 279 vhost_discard_vq_desc(vq, headcount); 280 return r; 281} 282 283/* Expects to be always run from workqueue - which acts as 284 * read-size critical section for our kind of RCU. */ 285static void handle_rx_big(struct vhost_net *net) 286{ 287 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX]; 288 unsigned out, in, log, s; 289 int head; 290 struct vhost_log *vq_log; 291 struct msghdr msg = { 292 .msg_name = NULL, 293 .msg_namelen = 0, 294 .msg_control = NULL, 295 .msg_controllen = 0, 296 .msg_iov = vq->iov, 297 .msg_flags = MSG_DONTWAIT, 298 }; 299 300 struct virtio_net_hdr hdr = { 301 .flags = 0, 302 .gso_type = VIRTIO_NET_HDR_GSO_NONE 303 }; 304 305 size_t len, total_len = 0; 306 int err; 307 size_t hdr_size; 308 struct socket *sock = rcu_dereference(vq->private_data); 309 if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue)) 310 return; 311 312 use_mm(net->dev.mm); 313 mutex_lock(&vq->mutex); 314 vhost_disable_notify(vq); 315 hdr_size = vq->vhost_hlen; 316 317 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? 318 vq->log : NULL; 319 320 for (;;) { 321 head = vhost_get_vq_desc(&net->dev, vq, vq->iov, 322 ARRAY_SIZE(vq->iov), 323 &out, &in, 324 vq_log, &log); 325 /* On error, stop handling until the next kick. */ 326 if (unlikely(head < 0)) 327 break; 328 /* OK, now we need to know about added descriptors. */ 329 if (head == vq->num) { 330 if (unlikely(vhost_enable_notify(vq))) { 331 /* They have slipped one in as we were 332 * doing that: check again. */ 333 vhost_disable_notify(vq); 334 continue; 335 } 336 /* Nothing new? Wait for eventfd to tell us 337 * they refilled. */ 338 break; 339 } 340 /* We don't need to be notified again. */ 341 if (out) { 342 vq_err(vq, "Unexpected descriptor format for RX: " 343 "out %d, int %d\n", 344 out, in); 345 break; 346 } 347 /* Skip header. TODO: support TSO/mergeable rx buffers. */ 348 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, in); 349 msg.msg_iovlen = in; 350 len = iov_length(vq->iov, in); 351 /* Sanity check */ 352 if (!len) { 353 vq_err(vq, "Unexpected header len for RX: " 354 "%zd expected %zd\n", 355 iov_length(vq->hdr, s), hdr_size); 356 break; 357 } 358 err = sock->ops->recvmsg(NULL, sock, &msg, 359 len, MSG_DONTWAIT | MSG_TRUNC); 360 /* TODO: Check specific error and bomb out unless EAGAIN? */ 361 if (err < 0) { 362 vhost_discard_vq_desc(vq, 1); 363 break; 364 } 365 /* TODO: Should check and handle checksum. */ 366 if (err > len) { 367 pr_debug("Discarded truncated rx packet: " 368 " len %d > %zd\n", err, len); 369 vhost_discard_vq_desc(vq, 1); 370 continue; 371 } 372 len = err; 373 err = memcpy_toiovec(vq->hdr, (unsigned char *)&hdr, hdr_size); 374 if (err) { 375 vq_err(vq, "Unable to write vnet_hdr at addr %p: %d\n", 376 vq->iov->iov_base, err); 377 break; 378 } 379 len += hdr_size; 380 vhost_add_used_and_signal(&net->dev, vq, head, len); 381 if (unlikely(vq_log)) 382 vhost_log_write(vq, vq_log, log, len); 383 total_len += len; 384 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 385 vhost_poll_queue(&vq->poll); 386 break; 387 } 388 } 389 390 mutex_unlock(&vq->mutex); 391 unuse_mm(net->dev.mm); 392} 393 394/* Expects to be always run from workqueue - which acts as 395 * read-size critical section for our kind of RCU. */ 396static void handle_rx_mergeable(struct vhost_net *net) 397{ 398 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX]; 399 unsigned uninitialized_var(in), log; 400 struct vhost_log *vq_log; 401 struct msghdr msg = { 402 .msg_name = NULL, 403 .msg_namelen = 0, 404 .msg_control = NULL, 405 .msg_controllen = 0, 406 .msg_iov = vq->iov, 407 .msg_flags = MSG_DONTWAIT, 408 }; 409 410 struct virtio_net_hdr_mrg_rxbuf hdr = { 411 .hdr.flags = 0, 412 .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE 413 }; 414 415 size_t total_len = 0; 416 int err, headcount; 417 size_t vhost_hlen, sock_hlen; 418 size_t vhost_len, sock_len; 419 struct socket *sock = rcu_dereference(vq->private_data); 420 if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue)) 421 return; 422 423 use_mm(net->dev.mm); 424 mutex_lock(&vq->mutex); 425 vhost_disable_notify(vq); 426 vhost_hlen = vq->vhost_hlen; 427 sock_hlen = vq->sock_hlen; 428 429 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? 430 vq->log : NULL; 431 432 while ((sock_len = peek_head_len(sock->sk))) { 433 sock_len += sock_hlen; 434 vhost_len = sock_len + vhost_hlen; 435 headcount = get_rx_bufs(vq, vq->heads, vhost_len, 436 &in, vq_log, &log); 437 /* On error, stop handling until the next kick. */ 438 if (unlikely(headcount < 0)) 439 break; 440 /* OK, now we need to know about added descriptors. */ 441 if (!headcount) { 442 if (unlikely(vhost_enable_notify(vq))) { 443 /* They have slipped one in as we were 444 * doing that: check again. */ 445 vhost_disable_notify(vq); 446 continue; 447 } 448 /* Nothing new? Wait for eventfd to tell us 449 * they refilled. */ 450 break; 451 } 452 /* We don't need to be notified again. */ 453 if (unlikely((vhost_hlen))) 454 /* Skip header. TODO: support TSO. */ 455 move_iovec_hdr(vq->iov, vq->hdr, vhost_hlen, in); 456 else 457 /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF: 458 * needed because sendmsg can modify msg_iov. */ 459 copy_iovec_hdr(vq->iov, vq->hdr, sock_hlen, in); 460 msg.msg_iovlen = in; 461 err = sock->ops->recvmsg(NULL, sock, &msg, 462 sock_len, MSG_DONTWAIT | MSG_TRUNC); 463 /* Userspace might have consumed the packet meanwhile: 464 * it's not supposed to do this usually, but might be hard 465 * to prevent. Discard data we got (if any) and keep going. */ 466 if (unlikely(err != sock_len)) { 467 pr_debug("Discarded rx packet: " 468 " len %d, expected %zd\n", err, sock_len); 469 vhost_discard_vq_desc(vq, headcount); 470 continue; 471 } 472 if (unlikely(vhost_hlen) && 473 memcpy_toiovecend(vq->hdr, (unsigned char *)&hdr, 0, 474 vhost_hlen)) { 475 vq_err(vq, "Unable to write vnet_hdr at addr %p\n", 476 vq->iov->iov_base); 477 break; 478 } 479 /* TODO: Should check and handle checksum. */ 480 if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF) && 481 memcpy_toiovecend(vq->hdr, (unsigned char *)&headcount, 482 offsetof(typeof(hdr), num_buffers), 483 sizeof hdr.num_buffers)) { 484 vq_err(vq, "Failed num_buffers write"); 485 vhost_discard_vq_desc(vq, headcount); 486 break; 487 } 488 vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, 489 headcount); 490 if (unlikely(vq_log)) 491 vhost_log_write(vq, vq_log, log, vhost_len); 492 total_len += vhost_len; 493 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 494 vhost_poll_queue(&vq->poll); 495 break; 496 } 497 } 498 499 mutex_unlock(&vq->mutex); 500 unuse_mm(net->dev.mm); 501} 502 503static void handle_rx(struct vhost_net *net) 504{ 505 if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF)) 506 handle_rx_mergeable(net); 507 else 508 handle_rx_big(net); 509} 510 511static void handle_tx_kick(struct vhost_work *work) 512{ 513 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 514 poll.work); 515 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 516 517 handle_tx(net); 518} 519 520static void handle_rx_kick(struct vhost_work *work) 521{ 522 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 523 poll.work); 524 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 525 526 handle_rx(net); 527} 528 529static void handle_tx_net(struct vhost_work *work) 530{ 531 struct vhost_net *net = container_of(work, struct vhost_net, 532 poll[VHOST_NET_VQ_TX].work); 533 handle_tx(net); 534} 535 536static void handle_rx_net(struct vhost_work *work) 537{ 538 struct vhost_net *net = container_of(work, struct vhost_net, 539 poll[VHOST_NET_VQ_RX].work); 540 handle_rx(net); 541} 542 543static int vhost_net_open(struct inode *inode, struct file *f) 544{ 545 struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL); 546 struct vhost_dev *dev; 547 int r; 548 549 if (!n) 550 return -ENOMEM; 551 552 dev = &n->dev; 553 n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick; 554 n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick; 555 r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX); 556 if (r < 0) { 557 kfree(n); 558 return r; 559 } 560 561 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev); 562 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev); 563 n->tx_poll_state = VHOST_NET_POLL_DISABLED; 564 565 f->private_data = n; 566 567 return 0; 568} 569 570static void vhost_net_disable_vq(struct vhost_net *n, 571 struct vhost_virtqueue *vq) 572{ 573 if (!vq->private_data) 574 return; 575 if (vq == n->vqs + VHOST_NET_VQ_TX) { 576 tx_poll_stop(n); 577 n->tx_poll_state = VHOST_NET_POLL_DISABLED; 578 } else 579 vhost_poll_stop(n->poll + VHOST_NET_VQ_RX); 580} 581 582static void vhost_net_enable_vq(struct vhost_net *n, 583 struct vhost_virtqueue *vq) 584{ 585 struct socket *sock = vq->private_data; 586 if (!sock) 587 return; 588 if (vq == n->vqs + VHOST_NET_VQ_TX) { 589 n->tx_poll_state = VHOST_NET_POLL_STOPPED; 590 tx_poll_start(n, sock); 591 } else 592 vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file); 593} 594 595static struct socket *vhost_net_stop_vq(struct vhost_net *n, 596 struct vhost_virtqueue *vq) 597{ 598 struct socket *sock; 599 600 mutex_lock(&vq->mutex); 601 sock = vq->private_data; 602 vhost_net_disable_vq(n, vq); 603 rcu_assign_pointer(vq->private_data, NULL); 604 mutex_unlock(&vq->mutex); 605 return sock; 606} 607 608static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 609 struct socket **rx_sock) 610{ 611 *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX); 612 *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX); 613} 614 615static void vhost_net_flush_vq(struct vhost_net *n, int index) 616{ 617 vhost_poll_flush(n->poll + index); 618 vhost_poll_flush(&n->dev.vqs[index].poll); 619} 620 621static void vhost_net_flush(struct vhost_net *n) 622{ 623 vhost_net_flush_vq(n, VHOST_NET_VQ_TX); 624 vhost_net_flush_vq(n, VHOST_NET_VQ_RX); 625} 626 627static int vhost_net_release(struct inode *inode, struct file *f) 628{ 629 struct vhost_net *n = f->private_data; 630 struct socket *tx_sock; 631 struct socket *rx_sock; 632 633 vhost_net_stop(n, &tx_sock, &rx_sock); 634 vhost_net_flush(n); 635 vhost_dev_cleanup(&n->dev); 636 if (tx_sock) 637 fput(tx_sock->file); 638 if (rx_sock) 639 fput(rx_sock->file); 640 /* We do an extra flush before freeing memory, 641 * since jobs can re-queue themselves. */ 642 vhost_net_flush(n); 643 kfree(n); 644 return 0; 645} 646 647static struct socket *get_raw_socket(int fd) 648{ 649 struct { 650 struct sockaddr_ll sa; 651 char buf[MAX_ADDR_LEN]; 652 } uaddr; 653 int uaddr_len = sizeof uaddr, r; 654 struct socket *sock = sockfd_lookup(fd, &r); 655 if (!sock) 656 return ERR_PTR(-ENOTSOCK); 657 658 /* Parameter checking */ 659 if (sock->sk->sk_type != SOCK_RAW) { 660 r = -ESOCKTNOSUPPORT; 661 goto err; 662 } 663 664 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 665 &uaddr_len, 0); 666 if (r) 667 goto err; 668 669 if (uaddr.sa.sll_family != AF_PACKET) { 670 r = -EPFNOSUPPORT; 671 goto err; 672 } 673 return sock; 674err: 675 fput(sock->file); 676 return ERR_PTR(r); 677} 678 679static struct socket *get_tap_socket(int fd) 680{ 681 struct file *file = fget(fd); 682 struct socket *sock; 683 if (!file) 684 return ERR_PTR(-EBADF); 685 sock = tun_get_socket(file); 686 if (!IS_ERR(sock)) 687 return sock; 688 sock = macvtap_get_socket(file); 689 if (IS_ERR(sock)) 690 fput(file); 691 return sock; 692} 693 694static struct socket *get_socket(int fd) 695{ 696 struct socket *sock; 697 /* special case to disable backend */ 698 if (fd == -1) 699 return NULL; 700 sock = get_raw_socket(fd); 701 if (!IS_ERR(sock)) 702 return sock; 703 sock = get_tap_socket(fd); 704 if (!IS_ERR(sock)) 705 return sock; 706 return ERR_PTR(-ENOTSOCK); 707} 708 709static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 710{ 711 struct socket *sock, *oldsock; 712 struct vhost_virtqueue *vq; 713 int r; 714 715 mutex_lock(&n->dev.mutex); 716 r = vhost_dev_check_owner(&n->dev); 717 if (r) 718 goto err; 719 720 if (index >= VHOST_NET_VQ_MAX) { 721 r = -ENOBUFS; 722 goto err; 723 } 724 vq = n->vqs + index; 725 mutex_lock(&vq->mutex); 726 727 /* Verify that ring has been setup correctly. */ 728 if (!vhost_vq_access_ok(vq)) { 729 r = -EFAULT; 730 goto err_vq; 731 } 732 sock = get_socket(fd); 733 if (IS_ERR(sock)) { 734 r = PTR_ERR(sock); 735 goto err_vq; 736 } 737 738 /* start polling new socket */ 739 oldsock = vq->private_data; 740 if (sock != oldsock) { 741 vhost_net_disable_vq(n, vq); 742 rcu_assign_pointer(vq->private_data, sock); 743 vhost_net_enable_vq(n, vq); 744 } 745 746 mutex_unlock(&vq->mutex); 747 748 if (oldsock) { 749 vhost_net_flush_vq(n, index); 750 fput(oldsock->file); 751 } 752 753 mutex_unlock(&n->dev.mutex); 754 return 0; 755 756err_vq: 757 mutex_unlock(&vq->mutex); 758err: 759 mutex_unlock(&n->dev.mutex); 760 return r; 761} 762 763static long vhost_net_reset_owner(struct vhost_net *n) 764{ 765 struct socket *tx_sock = NULL; 766 struct socket *rx_sock = NULL; 767 long err; 768 mutex_lock(&n->dev.mutex); 769 err = vhost_dev_check_owner(&n->dev); 770 if (err) 771 goto done; 772 vhost_net_stop(n, &tx_sock, &rx_sock); 773 vhost_net_flush(n); 774 err = vhost_dev_reset_owner(&n->dev); 775done: 776 mutex_unlock(&n->dev.mutex); 777 if (tx_sock) 778 fput(tx_sock->file); 779 if (rx_sock) 780 fput(rx_sock->file); 781 return err; 782} 783 784static int vhost_net_set_features(struct vhost_net *n, u64 features) 785{ 786 size_t vhost_hlen, sock_hlen, hdr_len; 787 int i; 788 789 hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? 790 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 791 sizeof(struct virtio_net_hdr); 792 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 793 /* vhost provides vnet_hdr */ 794 vhost_hlen = hdr_len; 795 sock_hlen = 0; 796 } else { 797 /* socket provides vnet_hdr */ 798 vhost_hlen = 0; 799 sock_hlen = hdr_len; 800 } 801 mutex_lock(&n->dev.mutex); 802 if ((features & (1 << VHOST_F_LOG_ALL)) && 803 !vhost_log_access_ok(&n->dev)) { 804 mutex_unlock(&n->dev.mutex); 805 return -EFAULT; 806 } 807 n->dev.acked_features = features; 808 smp_wmb(); 809 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 810 mutex_lock(&n->vqs[i].mutex); 811 n->vqs[i].vhost_hlen = vhost_hlen; 812 n->vqs[i].sock_hlen = sock_hlen; 813 mutex_unlock(&n->vqs[i].mutex); 814 } 815 vhost_net_flush(n); 816 mutex_unlock(&n->dev.mutex); 817 return 0; 818} 819 820static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 821 unsigned long arg) 822{ 823 struct vhost_net *n = f->private_data; 824 void __user *argp = (void __user *)arg; 825 u64 __user *featurep = argp; 826 struct vhost_vring_file backend; 827 u64 features; 828 int r; 829 switch (ioctl) { 830 case VHOST_NET_SET_BACKEND: 831 if (copy_from_user(&backend, argp, sizeof backend)) 832 return -EFAULT; 833 return vhost_net_set_backend(n, backend.index, backend.fd); 834 case VHOST_GET_FEATURES: 835 features = VHOST_FEATURES; 836 if (copy_to_user(featurep, &features, sizeof features)) 837 return -EFAULT; 838 return 0; 839 case VHOST_SET_FEATURES: 840 if (copy_from_user(&features, featurep, sizeof features)) 841 return -EFAULT; 842 if (features & ~VHOST_FEATURES) 843 return -EOPNOTSUPP; 844 return vhost_net_set_features(n, features); 845 case VHOST_RESET_OWNER: 846 return vhost_net_reset_owner(n); 847 default: 848 mutex_lock(&n->dev.mutex); 849 r = vhost_dev_ioctl(&n->dev, ioctl, arg); 850 vhost_net_flush(n); 851 mutex_unlock(&n->dev.mutex); 852 return r; 853 } 854} 855 856#ifdef CONFIG_COMPAT 857static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, 858 unsigned long arg) 859{ 860 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); 861} 862#endif 863 864static const struct file_operations vhost_net_fops = { 865 .owner = THIS_MODULE, 866 .release = vhost_net_release, 867 .unlocked_ioctl = vhost_net_ioctl, 868#ifdef CONFIG_COMPAT 869 .compat_ioctl = vhost_net_compat_ioctl, 870#endif 871 .open = vhost_net_open, 872}; 873 874static struct miscdevice vhost_net_misc = { 875 MISC_DYNAMIC_MINOR, 876 "vhost-net", 877 &vhost_net_fops, 878}; 879 880static int vhost_net_init(void) 881{ 882 return misc_register(&vhost_net_misc); 883} 884module_init(vhost_net_init); 885 886static void vhost_net_exit(void) 887{ 888 misc_deregister(&vhost_net_misc); 889} 890module_exit(vhost_net_exit); 891 892MODULE_VERSION("0.0.1"); 893MODULE_LICENSE("GPL v2"); 894MODULE_AUTHOR("Michael S. Tsirkin"); 895MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 896