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 struct vhost_ubuf_ref { 68 struct kref kref; 69 wait_queue_head_t wait; 70 struct vhost_virtqueue *vq; 71 }; 72 73 struct vhost_net_virtqueue { 74 struct vhost_virtqueue vq; 75 /* hdr is used to store the virtio header. 76 * Since each iovec has >= 1 byte length, we never need more than 77 * header length entries to store the header. */ 78 struct iovec hdr[sizeof(struct virtio_net_hdr_mrg_rxbuf)]; 79 size_t vhost_hlen; 80 size_t sock_hlen; 81 /* vhost zerocopy support fields below: */ 82 /* last used idx for outstanding DMA zerocopy buffers */ 83 int upend_idx; 84 /* first used idx for DMA done zerocopy buffers */ 85 int done_idx; 86 /* an array of userspace buffers info */ 87 struct ubuf_info *ubuf_info; 88 /* Reference counting for outstanding ubufs. 89 * Protected by vq mutex. Writers must also take device mutex. */ 90 struct vhost_ubuf_ref *ubufs; 91 }; 92 93 struct vhost_net { 94 struct vhost_dev dev; 95 struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX]; 96 struct vhost_poll poll[VHOST_NET_VQ_MAX]; 97 /* Number of TX recently submitted. 98 * Protected by tx vq lock. */ 99 unsigned tx_packets; 100 /* Number of times zerocopy TX recently failed. 101 * Protected by tx vq lock. */ 102 unsigned tx_zcopy_err; 103 /* Flush in progress. Protected by tx vq lock. */ 104 bool tx_flush; 105 }; 106 107 static unsigned vhost_zcopy_mask __read_mostly; 108 109 void vhost_enable_zcopy(int vq) 110 { 111 vhost_zcopy_mask |= 0x1 << vq; 112 } 113 114 static void vhost_zerocopy_done_signal(struct kref *kref) 115 { 116 struct vhost_ubuf_ref *ubufs = container_of(kref, struct vhost_ubuf_ref, 117 kref); 118 wake_up(&ubufs->wait); 119 } 120 121 struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *vq, 122 bool zcopy) 123 { 124 struct vhost_ubuf_ref *ubufs; 125 /* No zero copy backend? Nothing to count. */ 126 if (!zcopy) 127 return NULL; 128 ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL); 129 if (!ubufs) 130 return ERR_PTR(-ENOMEM); 131 kref_init(&ubufs->kref); 132 init_waitqueue_head(&ubufs->wait); 133 ubufs->vq = vq; 134 return ubufs; 135 } 136 137 void vhost_ubuf_put(struct vhost_ubuf_ref *ubufs) 138 { 139 kref_put(&ubufs->kref, vhost_zerocopy_done_signal); 140 } 141 142 void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs) 143 { 144 kref_put(&ubufs->kref, vhost_zerocopy_done_signal); 145 wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount)); 146 kfree(ubufs); 147 } 148 149 int vhost_net_set_ubuf_info(struct vhost_net *n) 150 { 151 bool zcopy; 152 int i; 153 154 for (i = 0; i < n->dev.nvqs; ++i) { 155 zcopy = vhost_zcopy_mask & (0x1 << i); 156 if (!zcopy) 157 continue; 158 n->vqs[i].ubuf_info = kmalloc(sizeof(*n->vqs[i].ubuf_info) * 159 UIO_MAXIOV, GFP_KERNEL); 160 if (!n->vqs[i].ubuf_info) 161 goto err; 162 } 163 return 0; 164 165 err: 166 while (i--) { 167 zcopy = vhost_zcopy_mask & (0x1 << i); 168 if (!zcopy) 169 continue; 170 kfree(n->vqs[i].ubuf_info); 171 } 172 return -ENOMEM; 173 } 174 175 void vhost_net_vq_reset(struct vhost_net *n) 176 { 177 int i; 178 179 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 180 n->vqs[i].done_idx = 0; 181 n->vqs[i].upend_idx = 0; 182 n->vqs[i].ubufs = NULL; 183 kfree(n->vqs[i].ubuf_info); 184 n->vqs[i].ubuf_info = NULL; 185 n->vqs[i].vhost_hlen = 0; 186 n->vqs[i].sock_hlen = 0; 187 } 188 189 } 190 191 static void vhost_net_tx_packet(struct vhost_net *net) 192 { 193 ++net->tx_packets; 194 if (net->tx_packets < 1024) 195 return; 196 net->tx_packets = 0; 197 net->tx_zcopy_err = 0; 198 } 199 200 static void vhost_net_tx_err(struct vhost_net *net) 201 { 202 ++net->tx_zcopy_err; 203 } 204 205 static bool vhost_net_tx_select_zcopy(struct vhost_net *net) 206 { 207 /* TX flush waits for outstanding DMAs to be done. 208 * Don't start new DMAs. 209 */ 210 return !net->tx_flush && 211 net->tx_packets / 64 >= net->tx_zcopy_err; 212 } 213 214 static bool vhost_sock_zcopy(struct socket *sock) 215 { 216 return unlikely(experimental_zcopytx) && 217 sock_flag(sock->sk, SOCK_ZEROCOPY); 218 } 219 220 /* Pop first len bytes from iovec. Return number of segments used. */ 221 static int move_iovec_hdr(struct iovec *from, struct iovec *to, 222 size_t len, int iov_count) 223 { 224 int seg = 0; 225 size_t size; 226 227 while (len && seg < iov_count) { 228 size = min(from->iov_len, len); 229 to->iov_base = from->iov_base; 230 to->iov_len = size; 231 from->iov_len -= size; 232 from->iov_base += size; 233 len -= size; 234 ++from; 235 ++to; 236 ++seg; 237 } 238 return seg; 239 } 240 /* Copy iovec entries for len bytes from iovec. */ 241 static void copy_iovec_hdr(const struct iovec *from, struct iovec *to, 242 size_t len, int iovcount) 243 { 244 int seg = 0; 245 size_t size; 246 247 while (len && seg < iovcount) { 248 size = min(from->iov_len, len); 249 to->iov_base = from->iov_base; 250 to->iov_len = size; 251 len -= size; 252 ++from; 253 ++to; 254 ++seg; 255 } 256 } 257 258 /* In case of DMA done not in order in lower device driver for some reason. 259 * upend_idx is used to track end of used idx, done_idx is used to track head 260 * of used idx. Once lower device DMA done contiguously, we will signal KVM 261 * guest used idx. 262 */ 263 static int vhost_zerocopy_signal_used(struct vhost_net *net, 264 struct vhost_virtqueue *vq) 265 { 266 struct vhost_net_virtqueue *nvq = 267 container_of(vq, struct vhost_net_virtqueue, vq); 268 int i; 269 int j = 0; 270 271 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { 272 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) 273 vhost_net_tx_err(net); 274 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { 275 vq->heads[i].len = VHOST_DMA_CLEAR_LEN; 276 vhost_add_used_and_signal(vq->dev, vq, 277 vq->heads[i].id, 0); 278 ++j; 279 } else 280 break; 281 } 282 if (j) 283 nvq->done_idx = i; 284 return j; 285 } 286 287 static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) 288 { 289 struct vhost_ubuf_ref *ubufs = ubuf->ctx; 290 struct vhost_virtqueue *vq = ubufs->vq; 291 int cnt = atomic_read(&ubufs->kref.refcount); 292 293 /* 294 * Trigger polling thread if guest stopped submitting new buffers: 295 * in this case, the refcount after decrement will eventually reach 1 296 * so here it is 2. 297 * We also trigger polling periodically after each 16 packets 298 * (the value 16 here is more or less arbitrary, it's tuned to trigger 299 * less than 10% of times). 300 */ 301 if (cnt <= 2 || !(cnt % 16)) 302 vhost_poll_queue(&vq->poll); 303 /* set len to mark this desc buffers done DMA */ 304 vq->heads[ubuf->desc].len = success ? 305 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; 306 vhost_ubuf_put(ubufs); 307 } 308 309 /* Expects to be always run from workqueue - which acts as 310 * read-size critical section for our kind of RCU. */ 311 static void handle_tx(struct vhost_net *net) 312 { 313 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 314 struct vhost_virtqueue *vq = &nvq->vq; 315 unsigned out, in, s; 316 int head; 317 struct msghdr msg = { 318 .msg_name = NULL, 319 .msg_namelen = 0, 320 .msg_control = NULL, 321 .msg_controllen = 0, 322 .msg_iov = vq->iov, 323 .msg_flags = MSG_DONTWAIT, 324 }; 325 size_t len, total_len = 0; 326 int err; 327 size_t hdr_size; 328 struct socket *sock; 329 struct vhost_ubuf_ref *uninitialized_var(ubufs); 330 bool zcopy, zcopy_used; 331 332 /* TODO: check that we are running from vhost_worker? */ 333 sock = rcu_dereference_check(vq->private_data, 1); 334 if (!sock) 335 return; 336 337 mutex_lock(&vq->mutex); 338 vhost_disable_notify(&net->dev, vq); 339 340 hdr_size = nvq->vhost_hlen; 341 zcopy = nvq->ubufs; 342 343 for (;;) { 344 /* Release DMAs done buffers first */ 345 if (zcopy) 346 vhost_zerocopy_signal_used(net, vq); 347 348 head = vhost_get_vq_desc(&net->dev, vq, vq->iov, 349 ARRAY_SIZE(vq->iov), 350 &out, &in, 351 NULL, NULL); 352 /* On error, stop handling until the next kick. */ 353 if (unlikely(head < 0)) 354 break; 355 /* Nothing new? Wait for eventfd to tell us they refilled. */ 356 if (head == vq->num) { 357 int num_pends; 358 359 /* If more outstanding DMAs, queue the work. 360 * Handle upend_idx wrap around 361 */ 362 num_pends = likely(nvq->upend_idx >= nvq->done_idx) ? 363 (nvq->upend_idx - nvq->done_idx) : 364 (nvq->upend_idx + UIO_MAXIOV - 365 nvq->done_idx); 366 if (unlikely(num_pends > VHOST_MAX_PEND)) 367 break; 368 if (unlikely(vhost_enable_notify(&net->dev, vq))) { 369 vhost_disable_notify(&net->dev, vq); 370 continue; 371 } 372 break; 373 } 374 if (in) { 375 vq_err(vq, "Unexpected descriptor format for TX: " 376 "out %d, int %d\n", out, in); 377 break; 378 } 379 /* Skip header. TODO: support TSO. */ 380 s = move_iovec_hdr(vq->iov, nvq->hdr, hdr_size, out); 381 msg.msg_iovlen = out; 382 len = iov_length(vq->iov, out); 383 /* Sanity check */ 384 if (!len) { 385 vq_err(vq, "Unexpected header len for TX: " 386 "%zd expected %zd\n", 387 iov_length(nvq->hdr, s), hdr_size); 388 break; 389 } 390 zcopy_used = zcopy && (len >= VHOST_GOODCOPY_LEN || 391 nvq->upend_idx != nvq->done_idx); 392 393 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 394 if (zcopy_used) { 395 vq->heads[nvq->upend_idx].id = head; 396 if (!vhost_net_tx_select_zcopy(net) || 397 len < VHOST_GOODCOPY_LEN) { 398 /* copy don't need to wait for DMA done */ 399 vq->heads[nvq->upend_idx].len = 400 VHOST_DMA_DONE_LEN; 401 msg.msg_control = NULL; 402 msg.msg_controllen = 0; 403 ubufs = NULL; 404 } else { 405 struct ubuf_info *ubuf; 406 ubuf = nvq->ubuf_info + nvq->upend_idx; 407 408 vq->heads[nvq->upend_idx].len = 409 VHOST_DMA_IN_PROGRESS; 410 ubuf->callback = vhost_zerocopy_callback; 411 ubuf->ctx = nvq->ubufs; 412 ubuf->desc = nvq->upend_idx; 413 msg.msg_control = ubuf; 414 msg.msg_controllen = sizeof(ubuf); 415 ubufs = nvq->ubufs; 416 kref_get(&ubufs->kref); 417 } 418 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; 419 } 420 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 421 err = sock->ops->sendmsg(NULL, sock, &msg, len); 422 if (unlikely(err < 0)) { 423 if (zcopy_used) { 424 if (ubufs) 425 vhost_ubuf_put(ubufs); 426 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) 427 % UIO_MAXIOV; 428 } 429 vhost_discard_vq_desc(vq, 1); 430 break; 431 } 432 if (err != len) 433 pr_debug("Truncated TX packet: " 434 " len %d != %zd\n", err, len); 435 if (!zcopy_used) 436 vhost_add_used_and_signal(&net->dev, vq, head, 0); 437 else 438 vhost_zerocopy_signal_used(net, vq); 439 total_len += len; 440 vhost_net_tx_packet(net); 441 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 442 vhost_poll_queue(&vq->poll); 443 break; 444 } 445 } 446 447 mutex_unlock(&vq->mutex); 448 } 449 450 static int peek_head_len(struct sock *sk) 451 { 452 struct sk_buff *head; 453 int len = 0; 454 unsigned long flags; 455 456 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); 457 head = skb_peek(&sk->sk_receive_queue); 458 if (likely(head)) { 459 len = head->len; 460 if (vlan_tx_tag_present(head)) 461 len += VLAN_HLEN; 462 } 463 464 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); 465 return len; 466 } 467 468 /* This is a multi-buffer version of vhost_get_desc, that works if 469 * vq has read descriptors only. 470 * @vq - the relevant virtqueue 471 * @datalen - data length we'll be reading 472 * @iovcount - returned count of io vectors we fill 473 * @log - vhost log 474 * @log_num - log offset 475 * @quota - headcount quota, 1 for big buffer 476 * returns number of buffer heads allocated, negative on error 477 */ 478 static int get_rx_bufs(struct vhost_virtqueue *vq, 479 struct vring_used_elem *heads, 480 int datalen, 481 unsigned *iovcount, 482 struct vhost_log *log, 483 unsigned *log_num, 484 unsigned int quota) 485 { 486 unsigned int out, in; 487 int seg = 0; 488 int headcount = 0; 489 unsigned d; 490 int r, nlogs = 0; 491 492 while (datalen > 0 && headcount < quota) { 493 if (unlikely(seg >= UIO_MAXIOV)) { 494 r = -ENOBUFS; 495 goto err; 496 } 497 d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg, 498 ARRAY_SIZE(vq->iov) - seg, &out, 499 &in, log, log_num); 500 if (d == vq->num) { 501 r = 0; 502 goto err; 503 } 504 if (unlikely(out || in <= 0)) { 505 vq_err(vq, "unexpected descriptor format for RX: " 506 "out %d, in %d\n", out, in); 507 r = -EINVAL; 508 goto err; 509 } 510 if (unlikely(log)) { 511 nlogs += *log_num; 512 log += *log_num; 513 } 514 heads[headcount].id = d; 515 heads[headcount].len = iov_length(vq->iov + seg, in); 516 datalen -= heads[headcount].len; 517 ++headcount; 518 seg += in; 519 } 520 heads[headcount - 1].len += datalen; 521 *iovcount = seg; 522 if (unlikely(log)) 523 *log_num = nlogs; 524 return headcount; 525 err: 526 vhost_discard_vq_desc(vq, headcount); 527 return r; 528 } 529 530 /* Expects to be always run from workqueue - which acts as 531 * read-size critical section for our kind of RCU. */ 532 static void handle_rx(struct vhost_net *net) 533 { 534 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; 535 struct vhost_virtqueue *vq = &nvq->vq; 536 unsigned uninitialized_var(in), log; 537 struct vhost_log *vq_log; 538 struct msghdr msg = { 539 .msg_name = NULL, 540 .msg_namelen = 0, 541 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 542 .msg_controllen = 0, 543 .msg_iov = vq->iov, 544 .msg_flags = MSG_DONTWAIT, 545 }; 546 struct virtio_net_hdr_mrg_rxbuf hdr = { 547 .hdr.flags = 0, 548 .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE 549 }; 550 size_t total_len = 0; 551 int err, mergeable; 552 s16 headcount; 553 size_t vhost_hlen, sock_hlen; 554 size_t vhost_len, sock_len; 555 /* TODO: check that we are running from vhost_worker? */ 556 struct socket *sock = rcu_dereference_check(vq->private_data, 1); 557 558 if (!sock) 559 return; 560 561 mutex_lock(&vq->mutex); 562 vhost_disable_notify(&net->dev, vq); 563 vhost_hlen = nvq->vhost_hlen; 564 sock_hlen = nvq->sock_hlen; 565 566 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? 567 vq->log : NULL; 568 mergeable = vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF); 569 570 while ((sock_len = peek_head_len(sock->sk))) { 571 sock_len += sock_hlen; 572 vhost_len = sock_len + vhost_hlen; 573 headcount = get_rx_bufs(vq, vq->heads, vhost_len, 574 &in, vq_log, &log, 575 likely(mergeable) ? UIO_MAXIOV : 1); 576 /* On error, stop handling until the next kick. */ 577 if (unlikely(headcount < 0)) 578 break; 579 /* OK, now we need to know about added descriptors. */ 580 if (!headcount) { 581 if (unlikely(vhost_enable_notify(&net->dev, vq))) { 582 /* They have slipped one in as we were 583 * doing that: check again. */ 584 vhost_disable_notify(&net->dev, vq); 585 continue; 586 } 587 /* Nothing new? Wait for eventfd to tell us 588 * they refilled. */ 589 break; 590 } 591 /* We don't need to be notified again. */ 592 if (unlikely((vhost_hlen))) 593 /* Skip header. TODO: support TSO. */ 594 move_iovec_hdr(vq->iov, nvq->hdr, vhost_hlen, in); 595 else 596 /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF: 597 * needed because recvmsg can modify msg_iov. */ 598 copy_iovec_hdr(vq->iov, nvq->hdr, sock_hlen, in); 599 msg.msg_iovlen = in; 600 err = sock->ops->recvmsg(NULL, sock, &msg, 601 sock_len, MSG_DONTWAIT | MSG_TRUNC); 602 /* Userspace might have consumed the packet meanwhile: 603 * it's not supposed to do this usually, but might be hard 604 * to prevent. Discard data we got (if any) and keep going. */ 605 if (unlikely(err != sock_len)) { 606 pr_debug("Discarded rx packet: " 607 " len %d, expected %zd\n", err, sock_len); 608 vhost_discard_vq_desc(vq, headcount); 609 continue; 610 } 611 if (unlikely(vhost_hlen) && 612 memcpy_toiovecend(nvq->hdr, (unsigned char *)&hdr, 0, 613 vhost_hlen)) { 614 vq_err(vq, "Unable to write vnet_hdr at addr %p\n", 615 vq->iov->iov_base); 616 break; 617 } 618 /* TODO: Should check and handle checksum. */ 619 if (likely(mergeable) && 620 memcpy_toiovecend(nvq->hdr, (unsigned char *)&headcount, 621 offsetof(typeof(hdr), num_buffers), 622 sizeof hdr.num_buffers)) { 623 vq_err(vq, "Failed num_buffers write"); 624 vhost_discard_vq_desc(vq, headcount); 625 break; 626 } 627 vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, 628 headcount); 629 if (unlikely(vq_log)) 630 vhost_log_write(vq, vq_log, log, vhost_len); 631 total_len += vhost_len; 632 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 633 vhost_poll_queue(&vq->poll); 634 break; 635 } 636 } 637 638 mutex_unlock(&vq->mutex); 639 } 640 641 static void handle_tx_kick(struct vhost_work *work) 642 { 643 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 644 poll.work); 645 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 646 647 handle_tx(net); 648 } 649 650 static void handle_rx_kick(struct vhost_work *work) 651 { 652 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 653 poll.work); 654 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 655 656 handle_rx(net); 657 } 658 659 static void handle_tx_net(struct vhost_work *work) 660 { 661 struct vhost_net *net = container_of(work, struct vhost_net, 662 poll[VHOST_NET_VQ_TX].work); 663 handle_tx(net); 664 } 665 666 static void handle_rx_net(struct vhost_work *work) 667 { 668 struct vhost_net *net = container_of(work, struct vhost_net, 669 poll[VHOST_NET_VQ_RX].work); 670 handle_rx(net); 671 } 672 673 static int vhost_net_open(struct inode *inode, struct file *f) 674 { 675 struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL); 676 struct vhost_dev *dev; 677 struct vhost_virtqueue **vqs; 678 int r, i; 679 680 if (!n) 681 return -ENOMEM; 682 vqs = kmalloc(VHOST_NET_VQ_MAX * sizeof(*vqs), GFP_KERNEL); 683 if (!vqs) { 684 kfree(n); 685 return -ENOMEM; 686 } 687 688 dev = &n->dev; 689 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; 690 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; 691 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; 692 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; 693 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 694 n->vqs[i].ubufs = NULL; 695 n->vqs[i].ubuf_info = NULL; 696 n->vqs[i].upend_idx = 0; 697 n->vqs[i].done_idx = 0; 698 n->vqs[i].vhost_hlen = 0; 699 n->vqs[i].sock_hlen = 0; 700 } 701 r = vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX); 702 if (r < 0) { 703 kfree(n); 704 kfree(vqs); 705 return r; 706 } 707 708 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev); 709 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev); 710 711 f->private_data = n; 712 713 return 0; 714 } 715 716 static void vhost_net_disable_vq(struct vhost_net *n, 717 struct vhost_virtqueue *vq) 718 { 719 struct vhost_net_virtqueue *nvq = 720 container_of(vq, struct vhost_net_virtqueue, vq); 721 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 722 if (!vq->private_data) 723 return; 724 vhost_poll_stop(poll); 725 } 726 727 static int vhost_net_enable_vq(struct vhost_net *n, 728 struct vhost_virtqueue *vq) 729 { 730 struct vhost_net_virtqueue *nvq = 731 container_of(vq, struct vhost_net_virtqueue, vq); 732 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 733 struct socket *sock; 734 735 sock = rcu_dereference_protected(vq->private_data, 736 lockdep_is_held(&vq->mutex)); 737 if (!sock) 738 return 0; 739 740 return vhost_poll_start(poll, sock->file); 741 } 742 743 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 744 struct vhost_virtqueue *vq) 745 { 746 struct socket *sock; 747 748 mutex_lock(&vq->mutex); 749 sock = rcu_dereference_protected(vq->private_data, 750 lockdep_is_held(&vq->mutex)); 751 vhost_net_disable_vq(n, vq); 752 rcu_assign_pointer(vq->private_data, NULL); 753 mutex_unlock(&vq->mutex); 754 return sock; 755 } 756 757 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 758 struct socket **rx_sock) 759 { 760 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); 761 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); 762 } 763 764 static void vhost_net_flush_vq(struct vhost_net *n, int index) 765 { 766 vhost_poll_flush(n->poll + index); 767 vhost_poll_flush(&n->vqs[index].vq.poll); 768 } 769 770 static void vhost_net_flush(struct vhost_net *n) 771 { 772 vhost_net_flush_vq(n, VHOST_NET_VQ_TX); 773 vhost_net_flush_vq(n, VHOST_NET_VQ_RX); 774 if (n->vqs[VHOST_NET_VQ_TX].ubufs) { 775 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 776 n->tx_flush = true; 777 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 778 /* Wait for all lower device DMAs done. */ 779 vhost_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); 780 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 781 n->tx_flush = false; 782 kref_init(&n->vqs[VHOST_NET_VQ_TX].ubufs->kref); 783 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 784 } 785 } 786 787 static int vhost_net_release(struct inode *inode, struct file *f) 788 { 789 struct vhost_net *n = f->private_data; 790 struct socket *tx_sock; 791 struct socket *rx_sock; 792 793 vhost_net_stop(n, &tx_sock, &rx_sock); 794 vhost_net_flush(n); 795 vhost_dev_stop(&n->dev); 796 vhost_dev_cleanup(&n->dev, false); 797 vhost_net_vq_reset(n); 798 if (tx_sock) 799 fput(tx_sock->file); 800 if (rx_sock) 801 fput(rx_sock->file); 802 /* We do an extra flush before freeing memory, 803 * since jobs can re-queue themselves. */ 804 vhost_net_flush(n); 805 kfree(n->dev.vqs); 806 kfree(n); 807 return 0; 808 } 809 810 static struct socket *get_raw_socket(int fd) 811 { 812 struct { 813 struct sockaddr_ll sa; 814 char buf[MAX_ADDR_LEN]; 815 } uaddr; 816 int uaddr_len = sizeof uaddr, r; 817 struct socket *sock = sockfd_lookup(fd, &r); 818 819 if (!sock) 820 return ERR_PTR(-ENOTSOCK); 821 822 /* Parameter checking */ 823 if (sock->sk->sk_type != SOCK_RAW) { 824 r = -ESOCKTNOSUPPORT; 825 goto err; 826 } 827 828 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 829 &uaddr_len, 0); 830 if (r) 831 goto err; 832 833 if (uaddr.sa.sll_family != AF_PACKET) { 834 r = -EPFNOSUPPORT; 835 goto err; 836 } 837 return sock; 838 err: 839 fput(sock->file); 840 return ERR_PTR(r); 841 } 842 843 static struct socket *get_tap_socket(int fd) 844 { 845 struct file *file = fget(fd); 846 struct socket *sock; 847 848 if (!file) 849 return ERR_PTR(-EBADF); 850 sock = tun_get_socket(file); 851 if (!IS_ERR(sock)) 852 return sock; 853 sock = macvtap_get_socket(file); 854 if (IS_ERR(sock)) 855 fput(file); 856 return sock; 857 } 858 859 static struct socket *get_socket(int fd) 860 { 861 struct socket *sock; 862 863 /* special case to disable backend */ 864 if (fd == -1) 865 return NULL; 866 sock = get_raw_socket(fd); 867 if (!IS_ERR(sock)) 868 return sock; 869 sock = get_tap_socket(fd); 870 if (!IS_ERR(sock)) 871 return sock; 872 return ERR_PTR(-ENOTSOCK); 873 } 874 875 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 876 { 877 struct socket *sock, *oldsock; 878 struct vhost_virtqueue *vq; 879 struct vhost_net_virtqueue *nvq; 880 struct vhost_ubuf_ref *ubufs, *oldubufs = NULL; 881 int r; 882 883 mutex_lock(&n->dev.mutex); 884 r = vhost_dev_check_owner(&n->dev); 885 if (r) 886 goto err; 887 888 if (index >= VHOST_NET_VQ_MAX) { 889 r = -ENOBUFS; 890 goto err; 891 } 892 vq = &n->vqs[index].vq; 893 nvq = &n->vqs[index]; 894 mutex_lock(&vq->mutex); 895 896 /* Verify that ring has been setup correctly. */ 897 if (!vhost_vq_access_ok(vq)) { 898 r = -EFAULT; 899 goto err_vq; 900 } 901 sock = get_socket(fd); 902 if (IS_ERR(sock)) { 903 r = PTR_ERR(sock); 904 goto err_vq; 905 } 906 907 /* start polling new socket */ 908 oldsock = rcu_dereference_protected(vq->private_data, 909 lockdep_is_held(&vq->mutex)); 910 if (sock != oldsock) { 911 ubufs = vhost_ubuf_alloc(vq, sock && vhost_sock_zcopy(sock)); 912 if (IS_ERR(ubufs)) { 913 r = PTR_ERR(ubufs); 914 goto err_ubufs; 915 } 916 917 vhost_net_disable_vq(n, vq); 918 rcu_assign_pointer(vq->private_data, sock); 919 r = vhost_init_used(vq); 920 if (r) 921 goto err_used; 922 r = vhost_net_enable_vq(n, vq); 923 if (r) 924 goto err_used; 925 926 oldubufs = nvq->ubufs; 927 nvq->ubufs = ubufs; 928 929 n->tx_packets = 0; 930 n->tx_zcopy_err = 0; 931 n->tx_flush = false; 932 } 933 934 mutex_unlock(&vq->mutex); 935 936 if (oldubufs) { 937 vhost_ubuf_put_and_wait(oldubufs); 938 mutex_lock(&vq->mutex); 939 vhost_zerocopy_signal_used(n, vq); 940 mutex_unlock(&vq->mutex); 941 } 942 943 if (oldsock) { 944 vhost_net_flush_vq(n, index); 945 fput(oldsock->file); 946 } 947 948 mutex_unlock(&n->dev.mutex); 949 return 0; 950 951 err_used: 952 rcu_assign_pointer(vq->private_data, oldsock); 953 vhost_net_enable_vq(n, vq); 954 if (ubufs) 955 vhost_ubuf_put_and_wait(ubufs); 956 err_ubufs: 957 fput(sock->file); 958 err_vq: 959 mutex_unlock(&vq->mutex); 960 err: 961 mutex_unlock(&n->dev.mutex); 962 return r; 963 } 964 965 static long vhost_net_reset_owner(struct vhost_net *n) 966 { 967 struct socket *tx_sock = NULL; 968 struct socket *rx_sock = NULL; 969 long err; 970 struct vhost_memory *memory; 971 972 mutex_lock(&n->dev.mutex); 973 err = vhost_dev_check_owner(&n->dev); 974 if (err) 975 goto done; 976 memory = vhost_dev_reset_owner_prepare(); 977 if (!memory) { 978 err = -ENOMEM; 979 goto done; 980 } 981 vhost_net_stop(n, &tx_sock, &rx_sock); 982 vhost_net_flush(n); 983 vhost_dev_reset_owner(&n->dev, memory); 984 vhost_net_vq_reset(n); 985 done: 986 mutex_unlock(&n->dev.mutex); 987 if (tx_sock) 988 fput(tx_sock->file); 989 if (rx_sock) 990 fput(rx_sock->file); 991 return err; 992 } 993 994 static int vhost_net_set_features(struct vhost_net *n, u64 features) 995 { 996 size_t vhost_hlen, sock_hlen, hdr_len; 997 int i; 998 999 hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? 1000 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 1001 sizeof(struct virtio_net_hdr); 1002 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 1003 /* vhost provides vnet_hdr */ 1004 vhost_hlen = hdr_len; 1005 sock_hlen = 0; 1006 } else { 1007 /* socket provides vnet_hdr */ 1008 vhost_hlen = 0; 1009 sock_hlen = hdr_len; 1010 } 1011 mutex_lock(&n->dev.mutex); 1012 if ((features & (1 << VHOST_F_LOG_ALL)) && 1013 !vhost_log_access_ok(&n->dev)) { 1014 mutex_unlock(&n->dev.mutex); 1015 return -EFAULT; 1016 } 1017 n->dev.acked_features = features; 1018 smp_wmb(); 1019 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1020 mutex_lock(&n->vqs[i].vq.mutex); 1021 n->vqs[i].vhost_hlen = vhost_hlen; 1022 n->vqs[i].sock_hlen = sock_hlen; 1023 mutex_unlock(&n->vqs[i].vq.mutex); 1024 } 1025 vhost_net_flush(n); 1026 mutex_unlock(&n->dev.mutex); 1027 return 0; 1028 } 1029 1030 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 1031 unsigned long arg) 1032 { 1033 struct vhost_net *n = f->private_data; 1034 void __user *argp = (void __user *)arg; 1035 u64 __user *featurep = argp; 1036 struct vhost_vring_file backend; 1037 u64 features; 1038 int r; 1039 1040 switch (ioctl) { 1041 case VHOST_NET_SET_BACKEND: 1042 if (copy_from_user(&backend, argp, sizeof backend)) 1043 return -EFAULT; 1044 return vhost_net_set_backend(n, backend.index, backend.fd); 1045 case VHOST_GET_FEATURES: 1046 features = VHOST_NET_FEATURES; 1047 if (copy_to_user(featurep, &features, sizeof features)) 1048 return -EFAULT; 1049 return 0; 1050 case VHOST_SET_FEATURES: 1051 if (copy_from_user(&features, featurep, sizeof features)) 1052 return -EFAULT; 1053 if (features & ~VHOST_NET_FEATURES) 1054 return -EOPNOTSUPP; 1055 return vhost_net_set_features(n, features); 1056 case VHOST_RESET_OWNER: 1057 return vhost_net_reset_owner(n); 1058 default: 1059 mutex_lock(&n->dev.mutex); 1060 if (ioctl == VHOST_SET_OWNER) { 1061 r = vhost_net_set_ubuf_info(n); 1062 if (r) 1063 goto out; 1064 } 1065 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 1066 if (r == -ENOIOCTLCMD) 1067 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 1068 else 1069 vhost_net_flush(n); 1070 out: 1071 mutex_unlock(&n->dev.mutex); 1072 return r; 1073 } 1074 } 1075 1076 #ifdef CONFIG_COMPAT 1077 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, 1078 unsigned long arg) 1079 { 1080 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); 1081 } 1082 #endif 1083 1084 static const struct file_operations vhost_net_fops = { 1085 .owner = THIS_MODULE, 1086 .release = vhost_net_release, 1087 .unlocked_ioctl = vhost_net_ioctl, 1088 #ifdef CONFIG_COMPAT 1089 .compat_ioctl = vhost_net_compat_ioctl, 1090 #endif 1091 .open = vhost_net_open, 1092 .llseek = noop_llseek, 1093 }; 1094 1095 static struct miscdevice vhost_net_misc = { 1096 .minor = VHOST_NET_MINOR, 1097 .name = "vhost-net", 1098 .fops = &vhost_net_fops, 1099 }; 1100 1101 static int vhost_net_init(void) 1102 { 1103 if (experimental_zcopytx) 1104 vhost_enable_zcopy(VHOST_NET_VQ_TX); 1105 return misc_register(&vhost_net_misc); 1106 } 1107 module_init(vhost_net_init); 1108 1109 static void vhost_net_exit(void) 1110 { 1111 misc_deregister(&vhost_net_misc); 1112 } 1113 module_exit(vhost_net_exit); 1114 1115 MODULE_VERSION("0.0.1"); 1116 MODULE_LICENSE("GPL v2"); 1117 MODULE_AUTHOR("Michael S. Tsirkin"); 1118 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1119 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1120 MODULE_ALIAS("devname:vhost-net"); 1121