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/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 #include <linux/if_vlan.h> 28 29 #include <net/sock.h> 30 31 #include "vhost.h" 32 33 static int experimental_zcopytx = 1; 34 module_param(experimental_zcopytx, int, 0444); 35 MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" 36 " 1 -Enable; 0 - Disable"); 37 38 /* Max number of bytes transferred before requeueing the job. 39 * Using this limit prevents one virtqueue from starving others. */ 40 #define VHOST_NET_WEIGHT 0x80000 41 42 /* MAX number of TX used buffers for outstanding zerocopy */ 43 #define VHOST_MAX_PEND 128 44 #define VHOST_GOODCOPY_LEN 256 45 46 /* 47 * For transmit, used buffer len is unused; we override it to track buffer 48 * status internally; used for zerocopy tx only. 49 */ 50 /* Lower device DMA failed */ 51 #define VHOST_DMA_FAILED_LEN 3 52 /* Lower device DMA done */ 53 #define VHOST_DMA_DONE_LEN 2 54 /* Lower device DMA in progress */ 55 #define VHOST_DMA_IN_PROGRESS 1 56 /* Buffer unused */ 57 #define VHOST_DMA_CLEAR_LEN 0 58 59 #define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN) 60 61 enum { 62 VHOST_NET_VQ_RX = 0, 63 VHOST_NET_VQ_TX = 1, 64 VHOST_NET_VQ_MAX = 2, 65 }; 66 67 enum vhost_net_poll_state { 68 VHOST_NET_POLL_DISABLED = 0, 69 VHOST_NET_POLL_STARTED = 1, 70 VHOST_NET_POLL_STOPPED = 2, 71 }; 72 73 struct vhost_net { 74 struct vhost_dev dev; 75 struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX]; 76 struct vhost_poll poll[VHOST_NET_VQ_MAX]; 77 /* Tells us whether we are polling a socket for TX. 78 * We only do this when socket buffer fills up. 79 * Protected by tx vq lock. */ 80 enum vhost_net_poll_state tx_poll_state; 81 /* Number of TX recently submitted. 82 * Protected by tx vq lock. */ 83 unsigned tx_packets; 84 /* Number of times zerocopy TX recently failed. 85 * Protected by tx vq lock. */ 86 unsigned tx_zcopy_err; 87 /* Flush in progress. Protected by tx vq lock. */ 88 bool tx_flush; 89 }; 90 91 static void vhost_net_tx_packet(struct vhost_net *net) 92 { 93 ++net->tx_packets; 94 if (net->tx_packets < 1024) 95 return; 96 net->tx_packets = 0; 97 net->tx_zcopy_err = 0; 98 } 99 100 static void vhost_net_tx_err(struct vhost_net *net) 101 { 102 ++net->tx_zcopy_err; 103 } 104 105 static bool vhost_net_tx_select_zcopy(struct vhost_net *net) 106 { 107 /* TX flush waits for outstanding DMAs to be done. 108 * Don't start new DMAs. 109 */ 110 return !net->tx_flush && 111 net->tx_packets / 64 >= net->tx_zcopy_err; 112 } 113 114 static bool vhost_sock_zcopy(struct socket *sock) 115 { 116 return unlikely(experimental_zcopytx) && 117 sock_flag(sock->sk, SOCK_ZEROCOPY); 118 } 119 120 /* Pop first len bytes from iovec. Return number of segments used. */ 121 static int move_iovec_hdr(struct iovec *from, struct iovec *to, 122 size_t len, int iov_count) 123 { 124 int seg = 0; 125 size_t size; 126 127 while (len && seg < iov_count) { 128 size = min(from->iov_len, len); 129 to->iov_base = from->iov_base; 130 to->iov_len = size; 131 from->iov_len -= size; 132 from->iov_base += size; 133 len -= size; 134 ++from; 135 ++to; 136 ++seg; 137 } 138 return seg; 139 } 140 /* Copy iovec entries for len bytes from iovec. */ 141 static void copy_iovec_hdr(const struct iovec *from, struct iovec *to, 142 size_t len, int iovcount) 143 { 144 int seg = 0; 145 size_t size; 146 147 while (len && seg < iovcount) { 148 size = min(from->iov_len, len); 149 to->iov_base = from->iov_base; 150 to->iov_len = size; 151 len -= size; 152 ++from; 153 ++to; 154 ++seg; 155 } 156 } 157 158 /* Caller must have TX VQ lock */ 159 static void tx_poll_stop(struct vhost_net *net) 160 { 161 if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED)) 162 return; 163 vhost_poll_stop(net->poll + VHOST_NET_VQ_TX); 164 net->tx_poll_state = VHOST_NET_POLL_STOPPED; 165 } 166 167 /* Caller must have TX VQ lock */ 168 static int tx_poll_start(struct vhost_net *net, struct socket *sock) 169 { 170 int ret; 171 172 if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED)) 173 return 0; 174 ret = vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file); 175 if (!ret) 176 net->tx_poll_state = VHOST_NET_POLL_STARTED; 177 return ret; 178 } 179 180 /* In case of DMA done not in order in lower device driver for some reason. 181 * upend_idx is used to track end of used idx, done_idx is used to track head 182 * of used idx. Once lower device DMA done contiguously, we will signal KVM 183 * guest used idx. 184 */ 185 static int vhost_zerocopy_signal_used(struct vhost_net *net, 186 struct vhost_virtqueue *vq) 187 { 188 int i; 189 int j = 0; 190 191 for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) { 192 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) 193 vhost_net_tx_err(net); 194 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { 195 vq->heads[i].len = VHOST_DMA_CLEAR_LEN; 196 vhost_add_used_and_signal(vq->dev, vq, 197 vq->heads[i].id, 0); 198 ++j; 199 } else 200 break; 201 } 202 if (j) 203 vq->done_idx = i; 204 return j; 205 } 206 207 static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) 208 { 209 struct vhost_ubuf_ref *ubufs = ubuf->ctx; 210 struct vhost_virtqueue *vq = ubufs->vq; 211 int cnt = atomic_read(&ubufs->kref.refcount); 212 213 /* 214 * Trigger polling thread if guest stopped submitting new buffers: 215 * in this case, the refcount after decrement will eventually reach 1 216 * so here it is 2. 217 * We also trigger polling periodically after each 16 packets 218 * (the value 16 here is more or less arbitrary, it's tuned to trigger 219 * less than 10% of times). 220 */ 221 if (cnt <= 2 || !(cnt % 16)) 222 vhost_poll_queue(&vq->poll); 223 /* set len to mark this desc buffers done DMA */ 224 vq->heads[ubuf->desc].len = success ? 225 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; 226 vhost_ubuf_put(ubufs); 227 } 228 229 /* Expects to be always run from workqueue - which acts as 230 * read-size critical section for our kind of RCU. */ 231 static void handle_tx(struct vhost_net *net) 232 { 233 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX]; 234 unsigned out, in, s; 235 int head; 236 struct msghdr msg = { 237 .msg_name = NULL, 238 .msg_namelen = 0, 239 .msg_control = NULL, 240 .msg_controllen = 0, 241 .msg_iov = vq->iov, 242 .msg_flags = MSG_DONTWAIT, 243 }; 244 size_t len, total_len = 0; 245 int err, wmem; 246 size_t hdr_size; 247 struct socket *sock; 248 struct vhost_ubuf_ref *uninitialized_var(ubufs); 249 bool zcopy, zcopy_used; 250 251 /* TODO: check that we are running from vhost_worker? */ 252 sock = rcu_dereference_check(vq->private_data, 1); 253 if (!sock) 254 return; 255 256 wmem = atomic_read(&sock->sk->sk_wmem_alloc); 257 if (wmem >= sock->sk->sk_sndbuf) { 258 mutex_lock(&vq->mutex); 259 tx_poll_start(net, sock); 260 mutex_unlock(&vq->mutex); 261 return; 262 } 263 264 mutex_lock(&vq->mutex); 265 vhost_disable_notify(&net->dev, vq); 266 267 if (wmem < sock->sk->sk_sndbuf / 2) 268 tx_poll_stop(net); 269 hdr_size = vq->vhost_hlen; 270 zcopy = vq->ubufs; 271 272 for (;;) { 273 /* Release DMAs done buffers first */ 274 if (zcopy) 275 vhost_zerocopy_signal_used(net, vq); 276 277 head = vhost_get_vq_desc(&net->dev, vq, vq->iov, 278 ARRAY_SIZE(vq->iov), 279 &out, &in, 280 NULL, NULL); 281 /* On error, stop handling until the next kick. */ 282 if (unlikely(head < 0)) 283 break; 284 /* Nothing new? Wait for eventfd to tell us they refilled. */ 285 if (head == vq->num) { 286 int num_pends; 287 288 wmem = atomic_read(&sock->sk->sk_wmem_alloc); 289 if (wmem >= sock->sk->sk_sndbuf * 3 / 4) { 290 tx_poll_start(net, sock); 291 set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); 292 break; 293 } 294 /* If more outstanding DMAs, queue the work. 295 * Handle upend_idx wrap around 296 */ 297 num_pends = likely(vq->upend_idx >= vq->done_idx) ? 298 (vq->upend_idx - vq->done_idx) : 299 (vq->upend_idx + UIO_MAXIOV - vq->done_idx); 300 if (unlikely(num_pends > VHOST_MAX_PEND)) { 301 tx_poll_start(net, sock); 302 set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); 303 break; 304 } 305 if (unlikely(vhost_enable_notify(&net->dev, vq))) { 306 vhost_disable_notify(&net->dev, vq); 307 continue; 308 } 309 break; 310 } 311 if (in) { 312 vq_err(vq, "Unexpected descriptor format for TX: " 313 "out %d, int %d\n", out, in); 314 break; 315 } 316 /* Skip header. TODO: support TSO. */ 317 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out); 318 msg.msg_iovlen = out; 319 len = iov_length(vq->iov, out); 320 /* Sanity check */ 321 if (!len) { 322 vq_err(vq, "Unexpected header len for TX: " 323 "%zd expected %zd\n", 324 iov_length(vq->hdr, s), hdr_size); 325 break; 326 } 327 zcopy_used = zcopy && (len >= VHOST_GOODCOPY_LEN || 328 vq->upend_idx != vq->done_idx); 329 330 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 331 if (zcopy_used) { 332 vq->heads[vq->upend_idx].id = head; 333 if (!vhost_net_tx_select_zcopy(net) || 334 len < VHOST_GOODCOPY_LEN) { 335 /* copy don't need to wait for DMA done */ 336 vq->heads[vq->upend_idx].len = 337 VHOST_DMA_DONE_LEN; 338 msg.msg_control = NULL; 339 msg.msg_controllen = 0; 340 ubufs = NULL; 341 } else { 342 struct ubuf_info *ubuf = &vq->ubuf_info[head]; 343 344 vq->heads[vq->upend_idx].len = 345 VHOST_DMA_IN_PROGRESS; 346 ubuf->callback = vhost_zerocopy_callback; 347 ubuf->ctx = vq->ubufs; 348 ubuf->desc = vq->upend_idx; 349 msg.msg_control = ubuf; 350 msg.msg_controllen = sizeof(ubuf); 351 ubufs = vq->ubufs; 352 kref_get(&ubufs->kref); 353 } 354 vq->upend_idx = (vq->upend_idx + 1) % UIO_MAXIOV; 355 } 356 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 357 err = sock->ops->sendmsg(NULL, sock, &msg, len); 358 if (unlikely(err < 0)) { 359 if (zcopy_used) { 360 if (ubufs) 361 vhost_ubuf_put(ubufs); 362 vq->upend_idx = ((unsigned)vq->upend_idx - 1) % 363 UIO_MAXIOV; 364 } 365 vhost_discard_vq_desc(vq, 1); 366 if (err == -EAGAIN || err == -ENOBUFS) 367 tx_poll_start(net, sock); 368 break; 369 } 370 if (err != len) 371 pr_debug("Truncated TX packet: " 372 " len %d != %zd\n", err, len); 373 if (!zcopy_used) 374 vhost_add_used_and_signal(&net->dev, vq, head, 0); 375 else 376 vhost_zerocopy_signal_used(net, vq); 377 total_len += len; 378 vhost_net_tx_packet(net); 379 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 380 vhost_poll_queue(&vq->poll); 381 break; 382 } 383 } 384 385 mutex_unlock(&vq->mutex); 386 } 387 388 static int peek_head_len(struct sock *sk) 389 { 390 struct sk_buff *head; 391 int len = 0; 392 unsigned long flags; 393 394 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); 395 head = skb_peek(&sk->sk_receive_queue); 396 if (likely(head)) { 397 len = head->len; 398 if (vlan_tx_tag_present(head)) 399 len += VLAN_HLEN; 400 } 401 402 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); 403 return len; 404 } 405 406 /* This is a multi-buffer version of vhost_get_desc, that works if 407 * vq has read descriptors only. 408 * @vq - the relevant virtqueue 409 * @datalen - data length we'll be reading 410 * @iovcount - returned count of io vectors we fill 411 * @log - vhost log 412 * @log_num - log offset 413 * @quota - headcount quota, 1 for big buffer 414 * returns number of buffer heads allocated, negative on error 415 */ 416 static int get_rx_bufs(struct vhost_virtqueue *vq, 417 struct vring_used_elem *heads, 418 int datalen, 419 unsigned *iovcount, 420 struct vhost_log *log, 421 unsigned *log_num, 422 unsigned int quota) 423 { 424 unsigned int out, in; 425 int seg = 0; 426 int headcount = 0; 427 unsigned d; 428 int r, nlogs = 0; 429 430 while (datalen > 0 && headcount < quota) { 431 if (unlikely(seg >= UIO_MAXIOV)) { 432 r = -ENOBUFS; 433 goto err; 434 } 435 d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg, 436 ARRAY_SIZE(vq->iov) - seg, &out, 437 &in, log, log_num); 438 if (d == vq->num) { 439 r = 0; 440 goto err; 441 } 442 if (unlikely(out || in <= 0)) { 443 vq_err(vq, "unexpected descriptor format for RX: " 444 "out %d, in %d\n", out, in); 445 r = -EINVAL; 446 goto err; 447 } 448 if (unlikely(log)) { 449 nlogs += *log_num; 450 log += *log_num; 451 } 452 heads[headcount].id = d; 453 heads[headcount].len = iov_length(vq->iov + seg, in); 454 datalen -= heads[headcount].len; 455 ++headcount; 456 seg += in; 457 } 458 heads[headcount - 1].len += datalen; 459 *iovcount = seg; 460 if (unlikely(log)) 461 *log_num = nlogs; 462 return headcount; 463 err: 464 vhost_discard_vq_desc(vq, headcount); 465 return r; 466 } 467 468 /* Expects to be always run from workqueue - which acts as 469 * read-size critical section for our kind of RCU. */ 470 static void handle_rx(struct vhost_net *net) 471 { 472 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX]; 473 unsigned uninitialized_var(in), log; 474 struct vhost_log *vq_log; 475 struct msghdr msg = { 476 .msg_name = NULL, 477 .msg_namelen = 0, 478 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 479 .msg_controllen = 0, 480 .msg_iov = vq->iov, 481 .msg_flags = MSG_DONTWAIT, 482 }; 483 struct virtio_net_hdr_mrg_rxbuf hdr = { 484 .hdr.flags = 0, 485 .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE 486 }; 487 size_t total_len = 0; 488 int err, mergeable; 489 s16 headcount; 490 size_t vhost_hlen, sock_hlen; 491 size_t vhost_len, sock_len; 492 /* TODO: check that we are running from vhost_worker? */ 493 struct socket *sock = rcu_dereference_check(vq->private_data, 1); 494 495 if (!sock) 496 return; 497 498 mutex_lock(&vq->mutex); 499 vhost_disable_notify(&net->dev, vq); 500 vhost_hlen = vq->vhost_hlen; 501 sock_hlen = vq->sock_hlen; 502 503 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? 504 vq->log : NULL; 505 mergeable = vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF); 506 507 while ((sock_len = peek_head_len(sock->sk))) { 508 sock_len += sock_hlen; 509 vhost_len = sock_len + vhost_hlen; 510 headcount = get_rx_bufs(vq, vq->heads, vhost_len, 511 &in, vq_log, &log, 512 likely(mergeable) ? UIO_MAXIOV : 1); 513 /* On error, stop handling until the next kick. */ 514 if (unlikely(headcount < 0)) 515 break; 516 /* OK, now we need to know about added descriptors. */ 517 if (!headcount) { 518 if (unlikely(vhost_enable_notify(&net->dev, vq))) { 519 /* They have slipped one in as we were 520 * doing that: check again. */ 521 vhost_disable_notify(&net->dev, vq); 522 continue; 523 } 524 /* Nothing new? Wait for eventfd to tell us 525 * they refilled. */ 526 break; 527 } 528 /* We don't need to be notified again. */ 529 if (unlikely((vhost_hlen))) 530 /* Skip header. TODO: support TSO. */ 531 move_iovec_hdr(vq->iov, vq->hdr, vhost_hlen, in); 532 else 533 /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF: 534 * needed because recvmsg can modify msg_iov. */ 535 copy_iovec_hdr(vq->iov, vq->hdr, sock_hlen, in); 536 msg.msg_iovlen = in; 537 err = sock->ops->recvmsg(NULL, sock, &msg, 538 sock_len, MSG_DONTWAIT | MSG_TRUNC); 539 /* Userspace might have consumed the packet meanwhile: 540 * it's not supposed to do this usually, but might be hard 541 * to prevent. Discard data we got (if any) and keep going. */ 542 if (unlikely(err != sock_len)) { 543 pr_debug("Discarded rx packet: " 544 " len %d, expected %zd\n", err, sock_len); 545 vhost_discard_vq_desc(vq, headcount); 546 continue; 547 } 548 if (unlikely(vhost_hlen) && 549 memcpy_toiovecend(vq->hdr, (unsigned char *)&hdr, 0, 550 vhost_hlen)) { 551 vq_err(vq, "Unable to write vnet_hdr at addr %p\n", 552 vq->iov->iov_base); 553 break; 554 } 555 /* TODO: Should check and handle checksum. */ 556 if (likely(mergeable) && 557 memcpy_toiovecend(vq->hdr, (unsigned char *)&headcount, 558 offsetof(typeof(hdr), num_buffers), 559 sizeof hdr.num_buffers)) { 560 vq_err(vq, "Failed num_buffers write"); 561 vhost_discard_vq_desc(vq, headcount); 562 break; 563 } 564 vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, 565 headcount); 566 if (unlikely(vq_log)) 567 vhost_log_write(vq, vq_log, log, vhost_len); 568 total_len += vhost_len; 569 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 570 vhost_poll_queue(&vq->poll); 571 break; 572 } 573 } 574 575 mutex_unlock(&vq->mutex); 576 } 577 578 static void handle_tx_kick(struct vhost_work *work) 579 { 580 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 581 poll.work); 582 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 583 584 handle_tx(net); 585 } 586 587 static void handle_rx_kick(struct vhost_work *work) 588 { 589 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 590 poll.work); 591 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 592 593 handle_rx(net); 594 } 595 596 static void handle_tx_net(struct vhost_work *work) 597 { 598 struct vhost_net *net = container_of(work, struct vhost_net, 599 poll[VHOST_NET_VQ_TX].work); 600 handle_tx(net); 601 } 602 603 static void handle_rx_net(struct vhost_work *work) 604 { 605 struct vhost_net *net = container_of(work, struct vhost_net, 606 poll[VHOST_NET_VQ_RX].work); 607 handle_rx(net); 608 } 609 610 static int vhost_net_open(struct inode *inode, struct file *f) 611 { 612 struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL); 613 struct vhost_dev *dev; 614 int r; 615 616 if (!n) 617 return -ENOMEM; 618 619 dev = &n->dev; 620 n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick; 621 n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick; 622 r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX); 623 if (r < 0) { 624 kfree(n); 625 return r; 626 } 627 628 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev); 629 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev); 630 n->tx_poll_state = VHOST_NET_POLL_DISABLED; 631 632 f->private_data = n; 633 634 return 0; 635 } 636 637 static void vhost_net_disable_vq(struct vhost_net *n, 638 struct vhost_virtqueue *vq) 639 { 640 if (!vq->private_data) 641 return; 642 if (vq == n->vqs + VHOST_NET_VQ_TX) { 643 tx_poll_stop(n); 644 n->tx_poll_state = VHOST_NET_POLL_DISABLED; 645 } else 646 vhost_poll_stop(n->poll + VHOST_NET_VQ_RX); 647 } 648 649 static int vhost_net_enable_vq(struct vhost_net *n, 650 struct vhost_virtqueue *vq) 651 { 652 struct socket *sock; 653 int ret; 654 655 sock = rcu_dereference_protected(vq->private_data, 656 lockdep_is_held(&vq->mutex)); 657 if (!sock) 658 return 0; 659 if (vq == n->vqs + VHOST_NET_VQ_TX) { 660 n->tx_poll_state = VHOST_NET_POLL_STOPPED; 661 ret = tx_poll_start(n, sock); 662 } else 663 ret = vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file); 664 665 return ret; 666 } 667 668 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 669 struct vhost_virtqueue *vq) 670 { 671 struct socket *sock; 672 673 mutex_lock(&vq->mutex); 674 sock = rcu_dereference_protected(vq->private_data, 675 lockdep_is_held(&vq->mutex)); 676 vhost_net_disable_vq(n, vq); 677 rcu_assign_pointer(vq->private_data, NULL); 678 mutex_unlock(&vq->mutex); 679 return sock; 680 } 681 682 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 683 struct socket **rx_sock) 684 { 685 *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX); 686 *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX); 687 } 688 689 static void vhost_net_flush_vq(struct vhost_net *n, int index) 690 { 691 vhost_poll_flush(n->poll + index); 692 vhost_poll_flush(&n->dev.vqs[index].poll); 693 } 694 695 static void vhost_net_flush(struct vhost_net *n) 696 { 697 vhost_net_flush_vq(n, VHOST_NET_VQ_TX); 698 vhost_net_flush_vq(n, VHOST_NET_VQ_RX); 699 if (n->dev.vqs[VHOST_NET_VQ_TX].ubufs) { 700 mutex_lock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex); 701 n->tx_flush = true; 702 mutex_unlock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex); 703 /* Wait for all lower device DMAs done. */ 704 vhost_ubuf_put_and_wait(n->dev.vqs[VHOST_NET_VQ_TX].ubufs); 705 mutex_lock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex); 706 n->tx_flush = false; 707 kref_init(&n->dev.vqs[VHOST_NET_VQ_TX].ubufs->kref); 708 mutex_unlock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex); 709 } 710 } 711 712 static int vhost_net_release(struct inode *inode, struct file *f) 713 { 714 struct vhost_net *n = f->private_data; 715 struct socket *tx_sock; 716 struct socket *rx_sock; 717 718 vhost_net_stop(n, &tx_sock, &rx_sock); 719 vhost_net_flush(n); 720 vhost_dev_stop(&n->dev); 721 vhost_dev_cleanup(&n->dev, false); 722 if (tx_sock) 723 fput(tx_sock->file); 724 if (rx_sock) 725 fput(rx_sock->file); 726 /* We do an extra flush before freeing memory, 727 * since jobs can re-queue themselves. */ 728 vhost_net_flush(n); 729 kfree(n); 730 return 0; 731 } 732 733 static struct socket *get_raw_socket(int fd) 734 { 735 struct { 736 struct sockaddr_ll sa; 737 char buf[MAX_ADDR_LEN]; 738 } uaddr; 739 int uaddr_len = sizeof uaddr, r; 740 struct socket *sock = sockfd_lookup(fd, &r); 741 742 if (!sock) 743 return ERR_PTR(-ENOTSOCK); 744 745 /* Parameter checking */ 746 if (sock->sk->sk_type != SOCK_RAW) { 747 r = -ESOCKTNOSUPPORT; 748 goto err; 749 } 750 751 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 752 &uaddr_len, 0); 753 if (r) 754 goto err; 755 756 if (uaddr.sa.sll_family != AF_PACKET) { 757 r = -EPFNOSUPPORT; 758 goto err; 759 } 760 return sock; 761 err: 762 fput(sock->file); 763 return ERR_PTR(r); 764 } 765 766 static struct socket *get_tap_socket(int fd) 767 { 768 struct file *file = fget(fd); 769 struct socket *sock; 770 771 if (!file) 772 return ERR_PTR(-EBADF); 773 sock = tun_get_socket(file); 774 if (!IS_ERR(sock)) 775 return sock; 776 sock = macvtap_get_socket(file); 777 if (IS_ERR(sock)) 778 fput(file); 779 return sock; 780 } 781 782 static struct socket *get_socket(int fd) 783 { 784 struct socket *sock; 785 786 /* special case to disable backend */ 787 if (fd == -1) 788 return NULL; 789 sock = get_raw_socket(fd); 790 if (!IS_ERR(sock)) 791 return sock; 792 sock = get_tap_socket(fd); 793 if (!IS_ERR(sock)) 794 return sock; 795 return ERR_PTR(-ENOTSOCK); 796 } 797 798 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 799 { 800 struct socket *sock, *oldsock; 801 struct vhost_virtqueue *vq; 802 struct vhost_ubuf_ref *ubufs, *oldubufs = NULL; 803 int r; 804 805 mutex_lock(&n->dev.mutex); 806 r = vhost_dev_check_owner(&n->dev); 807 if (r) 808 goto err; 809 810 if (index >= VHOST_NET_VQ_MAX) { 811 r = -ENOBUFS; 812 goto err; 813 } 814 vq = n->vqs + index; 815 mutex_lock(&vq->mutex); 816 817 /* Verify that ring has been setup correctly. */ 818 if (!vhost_vq_access_ok(vq)) { 819 r = -EFAULT; 820 goto err_vq; 821 } 822 sock = get_socket(fd); 823 if (IS_ERR(sock)) { 824 r = PTR_ERR(sock); 825 goto err_vq; 826 } 827 828 /* start polling new socket */ 829 oldsock = rcu_dereference_protected(vq->private_data, 830 lockdep_is_held(&vq->mutex)); 831 if (sock != oldsock) { 832 ubufs = vhost_ubuf_alloc(vq, sock && vhost_sock_zcopy(sock)); 833 if (IS_ERR(ubufs)) { 834 r = PTR_ERR(ubufs); 835 goto err_ubufs; 836 } 837 838 vhost_net_disable_vq(n, vq); 839 rcu_assign_pointer(vq->private_data, sock); 840 r = vhost_init_used(vq); 841 if (r) 842 goto err_used; 843 r = vhost_net_enable_vq(n, vq); 844 if (r) 845 goto err_used; 846 847 oldubufs = vq->ubufs; 848 vq->ubufs = ubufs; 849 850 n->tx_packets = 0; 851 n->tx_zcopy_err = 0; 852 n->tx_flush = false; 853 } 854 855 mutex_unlock(&vq->mutex); 856 857 if (oldubufs) { 858 vhost_ubuf_put_and_wait(oldubufs); 859 mutex_lock(&vq->mutex); 860 vhost_zerocopy_signal_used(n, vq); 861 mutex_unlock(&vq->mutex); 862 } 863 864 if (oldsock) { 865 vhost_net_flush_vq(n, index); 866 fput(oldsock->file); 867 } 868 869 mutex_unlock(&n->dev.mutex); 870 return 0; 871 872 err_used: 873 rcu_assign_pointer(vq->private_data, oldsock); 874 vhost_net_enable_vq(n, vq); 875 if (ubufs) 876 vhost_ubuf_put_and_wait(ubufs); 877 err_ubufs: 878 fput(sock->file); 879 err_vq: 880 mutex_unlock(&vq->mutex); 881 err: 882 mutex_unlock(&n->dev.mutex); 883 return r; 884 } 885 886 static long vhost_net_reset_owner(struct vhost_net *n) 887 { 888 struct socket *tx_sock = NULL; 889 struct socket *rx_sock = NULL; 890 long err; 891 892 mutex_lock(&n->dev.mutex); 893 err = vhost_dev_check_owner(&n->dev); 894 if (err) 895 goto done; 896 vhost_net_stop(n, &tx_sock, &rx_sock); 897 vhost_net_flush(n); 898 err = vhost_dev_reset_owner(&n->dev); 899 done: 900 mutex_unlock(&n->dev.mutex); 901 if (tx_sock) 902 fput(tx_sock->file); 903 if (rx_sock) 904 fput(rx_sock->file); 905 return err; 906 } 907 908 static int vhost_net_set_features(struct vhost_net *n, u64 features) 909 { 910 size_t vhost_hlen, sock_hlen, hdr_len; 911 int i; 912 913 hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? 914 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 915 sizeof(struct virtio_net_hdr); 916 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 917 /* vhost provides vnet_hdr */ 918 vhost_hlen = hdr_len; 919 sock_hlen = 0; 920 } else { 921 /* socket provides vnet_hdr */ 922 vhost_hlen = 0; 923 sock_hlen = hdr_len; 924 } 925 mutex_lock(&n->dev.mutex); 926 if ((features & (1 << VHOST_F_LOG_ALL)) && 927 !vhost_log_access_ok(&n->dev)) { 928 mutex_unlock(&n->dev.mutex); 929 return -EFAULT; 930 } 931 n->dev.acked_features = features; 932 smp_wmb(); 933 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 934 mutex_lock(&n->vqs[i].mutex); 935 n->vqs[i].vhost_hlen = vhost_hlen; 936 n->vqs[i].sock_hlen = sock_hlen; 937 mutex_unlock(&n->vqs[i].mutex); 938 } 939 vhost_net_flush(n); 940 mutex_unlock(&n->dev.mutex); 941 return 0; 942 } 943 944 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 945 unsigned long arg) 946 { 947 struct vhost_net *n = f->private_data; 948 void __user *argp = (void __user *)arg; 949 u64 __user *featurep = argp; 950 struct vhost_vring_file backend; 951 u64 features; 952 int r; 953 954 switch (ioctl) { 955 case VHOST_NET_SET_BACKEND: 956 if (copy_from_user(&backend, argp, sizeof backend)) 957 return -EFAULT; 958 return vhost_net_set_backend(n, backend.index, backend.fd); 959 case VHOST_GET_FEATURES: 960 features = VHOST_NET_FEATURES; 961 if (copy_to_user(featurep, &features, sizeof features)) 962 return -EFAULT; 963 return 0; 964 case VHOST_SET_FEATURES: 965 if (copy_from_user(&features, featurep, sizeof features)) 966 return -EFAULT; 967 if (features & ~VHOST_NET_FEATURES) 968 return -EOPNOTSUPP; 969 return vhost_net_set_features(n, features); 970 case VHOST_RESET_OWNER: 971 return vhost_net_reset_owner(n); 972 default: 973 mutex_lock(&n->dev.mutex); 974 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 975 if (r == -ENOIOCTLCMD) 976 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 977 else 978 vhost_net_flush(n); 979 mutex_unlock(&n->dev.mutex); 980 return r; 981 } 982 } 983 984 #ifdef CONFIG_COMPAT 985 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, 986 unsigned long arg) 987 { 988 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); 989 } 990 #endif 991 992 static const struct file_operations vhost_net_fops = { 993 .owner = THIS_MODULE, 994 .release = vhost_net_release, 995 .unlocked_ioctl = vhost_net_ioctl, 996 #ifdef CONFIG_COMPAT 997 .compat_ioctl = vhost_net_compat_ioctl, 998 #endif 999 .open = vhost_net_open, 1000 .llseek = noop_llseek, 1001 }; 1002 1003 static struct miscdevice vhost_net_misc = { 1004 .minor = VHOST_NET_MINOR, 1005 .name = "vhost-net", 1006 .fops = &vhost_net_fops, 1007 }; 1008 1009 static int vhost_net_init(void) 1010 { 1011 if (experimental_zcopytx) 1012 vhost_enable_zcopy(VHOST_NET_VQ_TX); 1013 return misc_register(&vhost_net_misc); 1014 } 1015 module_init(vhost_net_init); 1016 1017 static void vhost_net_exit(void) 1018 { 1019 misc_deregister(&vhost_net_misc); 1020 } 1021 module_exit(vhost_net_exit); 1022 1023 MODULE_VERSION("0.0.1"); 1024 MODULE_LICENSE("GPL v2"); 1025 MODULE_AUTHOR("Michael S. Tsirkin"); 1026 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1027 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1028 MODULE_ALIAS("devname:vhost-net"); 1029