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