1 /* Copyright (C) 2009 Red Hat, Inc. 2 * Author: Michael S. Tsirkin <mst@redhat.com> 3 * 4 * This work is licensed under the terms of the GNU GPL, version 2. 5 * 6 * virtio-net server in host kernel. 7 */ 8 9 #include <linux/compat.h> 10 #include <linux/eventfd.h> 11 #include <linux/vhost.h> 12 #include <linux/virtio_net.h> 13 #include <linux/miscdevice.h> 14 #include <linux/module.h> 15 #include <linux/moduleparam.h> 16 #include <linux/mutex.h> 17 #include <linux/workqueue.h> 18 #include <linux/file.h> 19 #include <linux/slab.h> 20 21 #include <linux/net.h> 22 #include <linux/if_packet.h> 23 #include <linux/if_arp.h> 24 #include <linux/if_tun.h> 25 #include <linux/if_macvlan.h> 26 #include <linux/if_vlan.h> 27 28 #include <net/sock.h> 29 30 #include "vhost.h" 31 32 static int experimental_zcopytx = 1; 33 module_param(experimental_zcopytx, int, 0444); 34 MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" 35 " 1 -Enable; 0 - Disable"); 36 37 /* Max number of bytes transferred before requeueing the job. 38 * Using this limit prevents one virtqueue from starving others. */ 39 #define VHOST_NET_WEIGHT 0x80000 40 41 /* MAX number of TX used buffers for outstanding zerocopy */ 42 #define VHOST_MAX_PEND 128 43 #define VHOST_GOODCOPY_LEN 256 44 45 /* 46 * For transmit, used buffer len is unused; we override it to track buffer 47 * status internally; used for zerocopy tx only. 48 */ 49 /* Lower device DMA failed */ 50 #define VHOST_DMA_FAILED_LEN 3 51 /* Lower device DMA done */ 52 #define VHOST_DMA_DONE_LEN 2 53 /* Lower device DMA in progress */ 54 #define VHOST_DMA_IN_PROGRESS 1 55 /* Buffer unused */ 56 #define VHOST_DMA_CLEAR_LEN 0 57 58 #define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN) 59 60 enum { 61 VHOST_NET_FEATURES = VHOST_FEATURES | 62 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | 63 (1ULL << VIRTIO_NET_F_MRG_RXBUF), 64 }; 65 66 enum { 67 VHOST_NET_VQ_RX = 0, 68 VHOST_NET_VQ_TX = 1, 69 VHOST_NET_VQ_MAX = 2, 70 }; 71 72 struct vhost_net_ubuf_ref { 73 /* refcount follows semantics similar to kref: 74 * 0: object is released 75 * 1: no outstanding ubufs 76 * >1: outstanding ubufs 77 */ 78 atomic_t refcount; 79 wait_queue_head_t wait; 80 struct vhost_virtqueue *vq; 81 }; 82 83 struct vhost_net_virtqueue { 84 struct vhost_virtqueue vq; 85 /* hdr is used to store the virtio header. 86 * Since each iovec has >= 1 byte length, we never need more than 87 * header length entries to store the header. */ 88 struct iovec hdr[sizeof(struct virtio_net_hdr_mrg_rxbuf)]; 89 size_t vhost_hlen; 90 size_t sock_hlen; 91 /* vhost zerocopy support fields below: */ 92 /* last used idx for outstanding DMA zerocopy buffers */ 93 int upend_idx; 94 /* first used idx for DMA done zerocopy buffers */ 95 int done_idx; 96 /* an array of userspace buffers info */ 97 struct ubuf_info *ubuf_info; 98 /* Reference counting for outstanding ubufs. 99 * Protected by vq mutex. Writers must also take device mutex. */ 100 struct vhost_net_ubuf_ref *ubufs; 101 }; 102 103 struct vhost_net { 104 struct vhost_dev dev; 105 struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX]; 106 struct vhost_poll poll[VHOST_NET_VQ_MAX]; 107 /* Number of TX recently submitted. 108 * Protected by tx vq lock. */ 109 unsigned tx_packets; 110 /* Number of times zerocopy TX recently failed. 111 * Protected by tx vq lock. */ 112 unsigned tx_zcopy_err; 113 /* Flush in progress. Protected by tx vq lock. */ 114 bool tx_flush; 115 }; 116 117 static unsigned vhost_net_zcopy_mask __read_mostly; 118 119 static void vhost_net_enable_zcopy(int vq) 120 { 121 vhost_net_zcopy_mask |= 0x1 << vq; 122 } 123 124 static struct vhost_net_ubuf_ref * 125 vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy) 126 { 127 struct vhost_net_ubuf_ref *ubufs; 128 /* No zero copy backend? Nothing to count. */ 129 if (!zcopy) 130 return NULL; 131 ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL); 132 if (!ubufs) 133 return ERR_PTR(-ENOMEM); 134 atomic_set(&ubufs->refcount, 1); 135 init_waitqueue_head(&ubufs->wait); 136 ubufs->vq = vq; 137 return ubufs; 138 } 139 140 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs) 141 { 142 int r = atomic_sub_return(1, &ubufs->refcount); 143 if (unlikely(!r)) 144 wake_up(&ubufs->wait); 145 return r; 146 } 147 148 static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) 149 { 150 vhost_net_ubuf_put(ubufs); 151 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); 152 } 153 154 static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) 155 { 156 vhost_net_ubuf_put_and_wait(ubufs); 157 kfree(ubufs); 158 } 159 160 static void vhost_net_clear_ubuf_info(struct vhost_net *n) 161 { 162 int i; 163 164 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 165 kfree(n->vqs[i].ubuf_info); 166 n->vqs[i].ubuf_info = NULL; 167 } 168 } 169 170 static int vhost_net_set_ubuf_info(struct vhost_net *n) 171 { 172 bool zcopy; 173 int i; 174 175 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 176 zcopy = vhost_net_zcopy_mask & (0x1 << i); 177 if (!zcopy) 178 continue; 179 n->vqs[i].ubuf_info = kmalloc(sizeof(*n->vqs[i].ubuf_info) * 180 UIO_MAXIOV, GFP_KERNEL); 181 if (!n->vqs[i].ubuf_info) 182 goto err; 183 } 184 return 0; 185 186 err: 187 vhost_net_clear_ubuf_info(n); 188 return -ENOMEM; 189 } 190 191 static void vhost_net_vq_reset(struct vhost_net *n) 192 { 193 int i; 194 195 vhost_net_clear_ubuf_info(n); 196 197 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 198 n->vqs[i].done_idx = 0; 199 n->vqs[i].upend_idx = 0; 200 n->vqs[i].ubufs = NULL; 201 n->vqs[i].vhost_hlen = 0; 202 n->vqs[i].sock_hlen = 0; 203 } 204 205 } 206 207 static void vhost_net_tx_packet(struct vhost_net *net) 208 { 209 ++net->tx_packets; 210 if (net->tx_packets < 1024) 211 return; 212 net->tx_packets = 0; 213 net->tx_zcopy_err = 0; 214 } 215 216 static void vhost_net_tx_err(struct vhost_net *net) 217 { 218 ++net->tx_zcopy_err; 219 } 220 221 static bool vhost_net_tx_select_zcopy(struct vhost_net *net) 222 { 223 /* TX flush waits for outstanding DMAs to be done. 224 * Don't start new DMAs. 225 */ 226 return !net->tx_flush && 227 net->tx_packets / 64 >= net->tx_zcopy_err; 228 } 229 230 static bool vhost_sock_zcopy(struct socket *sock) 231 { 232 return unlikely(experimental_zcopytx) && 233 sock_flag(sock->sk, SOCK_ZEROCOPY); 234 } 235 236 /* Pop first len bytes from iovec. Return number of segments used. */ 237 static int move_iovec_hdr(struct iovec *from, struct iovec *to, 238 size_t len, int iov_count) 239 { 240 int seg = 0; 241 size_t size; 242 243 while (len && seg < iov_count) { 244 size = min(from->iov_len, len); 245 to->iov_base = from->iov_base; 246 to->iov_len = size; 247 from->iov_len -= size; 248 from->iov_base += size; 249 len -= size; 250 ++from; 251 ++to; 252 ++seg; 253 } 254 return seg; 255 } 256 /* Copy iovec entries for len bytes from iovec. */ 257 static void copy_iovec_hdr(const struct iovec *from, struct iovec *to, 258 size_t len, int iovcount) 259 { 260 int seg = 0; 261 size_t size; 262 263 while (len && seg < iovcount) { 264 size = min(from->iov_len, len); 265 to->iov_base = from->iov_base; 266 to->iov_len = size; 267 len -= size; 268 ++from; 269 ++to; 270 ++seg; 271 } 272 } 273 274 /* In case of DMA done not in order in lower device driver for some reason. 275 * upend_idx is used to track end of used idx, done_idx is used to track head 276 * of used idx. Once lower device DMA done contiguously, we will signal KVM 277 * guest used idx. 278 */ 279 static void vhost_zerocopy_signal_used(struct vhost_net *net, 280 struct vhost_virtqueue *vq) 281 { 282 struct vhost_net_virtqueue *nvq = 283 container_of(vq, struct vhost_net_virtqueue, vq); 284 int i, add; 285 int j = 0; 286 287 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { 288 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) 289 vhost_net_tx_err(net); 290 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { 291 vq->heads[i].len = VHOST_DMA_CLEAR_LEN; 292 ++j; 293 } else 294 break; 295 } 296 while (j) { 297 add = min(UIO_MAXIOV - nvq->done_idx, j); 298 vhost_add_used_and_signal_n(vq->dev, vq, 299 &vq->heads[nvq->done_idx], add); 300 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; 301 j -= add; 302 } 303 } 304 305 static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) 306 { 307 struct vhost_net_ubuf_ref *ubufs = ubuf->ctx; 308 struct vhost_virtqueue *vq = ubufs->vq; 309 int cnt; 310 311 rcu_read_lock_bh(); 312 313 /* set len to mark this desc buffers done DMA */ 314 vq->heads[ubuf->desc].len = success ? 315 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; 316 cnt = vhost_net_ubuf_put(ubufs); 317 318 /* 319 * Trigger polling thread if guest stopped submitting new buffers: 320 * in this case, the refcount after decrement will eventually reach 1. 321 * We also trigger polling periodically after each 16 packets 322 * (the value 16 here is more or less arbitrary, it's tuned to trigger 323 * less than 10% of times). 324 */ 325 if (cnt <= 1 || !(cnt % 16)) 326 vhost_poll_queue(&vq->poll); 327 328 rcu_read_unlock_bh(); 329 } 330 331 /* Expects to be always run from workqueue - which acts as 332 * read-size critical section for our kind of RCU. */ 333 static void handle_tx(struct vhost_net *net) 334 { 335 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 336 struct vhost_virtqueue *vq = &nvq->vq; 337 unsigned out, in, s; 338 int head; 339 struct msghdr msg = { 340 .msg_name = NULL, 341 .msg_namelen = 0, 342 .msg_control = NULL, 343 .msg_controllen = 0, 344 .msg_iov = vq->iov, 345 .msg_flags = MSG_DONTWAIT, 346 }; 347 size_t len, total_len = 0; 348 int err; 349 size_t hdr_size; 350 struct socket *sock; 351 struct vhost_net_ubuf_ref *uninitialized_var(ubufs); 352 bool zcopy, zcopy_used; 353 354 mutex_lock(&vq->mutex); 355 sock = vq->private_data; 356 if (!sock) 357 goto out; 358 359 vhost_disable_notify(&net->dev, vq); 360 361 hdr_size = nvq->vhost_hlen; 362 zcopy = nvq->ubufs; 363 364 for (;;) { 365 /* Release DMAs done buffers first */ 366 if (zcopy) 367 vhost_zerocopy_signal_used(net, vq); 368 369 /* If more outstanding DMAs, queue the work. 370 * Handle upend_idx wrap around 371 */ 372 if (unlikely((nvq->upend_idx + vq->num - VHOST_MAX_PEND) 373 % UIO_MAXIOV == nvq->done_idx)) 374 break; 375 376 head = vhost_get_vq_desc(&net->dev, vq, vq->iov, 377 ARRAY_SIZE(vq->iov), 378 &out, &in, 379 NULL, NULL); 380 /* On error, stop handling until the next kick. */ 381 if (unlikely(head < 0)) 382 break; 383 /* Nothing new? Wait for eventfd to tell us they refilled. */ 384 if (head == vq->num) { 385 if (unlikely(vhost_enable_notify(&net->dev, vq))) { 386 vhost_disable_notify(&net->dev, vq); 387 continue; 388 } 389 break; 390 } 391 if (in) { 392 vq_err(vq, "Unexpected descriptor format for TX: " 393 "out %d, int %d\n", out, in); 394 break; 395 } 396 /* Skip header. TODO: support TSO. */ 397 s = move_iovec_hdr(vq->iov, nvq->hdr, hdr_size, out); 398 msg.msg_iovlen = out; 399 len = iov_length(vq->iov, out); 400 /* Sanity check */ 401 if (!len) { 402 vq_err(vq, "Unexpected header len for TX: " 403 "%zd expected %zd\n", 404 iov_length(nvq->hdr, s), hdr_size); 405 break; 406 } 407 408 zcopy_used = zcopy && len >= VHOST_GOODCOPY_LEN 409 && (nvq->upend_idx + 1) % UIO_MAXIOV != 410 nvq->done_idx 411 && vhost_net_tx_select_zcopy(net); 412 413 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 414 if (zcopy_used) { 415 struct ubuf_info *ubuf; 416 ubuf = nvq->ubuf_info + nvq->upend_idx; 417 418 vq->heads[nvq->upend_idx].id = head; 419 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; 420 ubuf->callback = vhost_zerocopy_callback; 421 ubuf->ctx = nvq->ubufs; 422 ubuf->desc = nvq->upend_idx; 423 msg.msg_control = ubuf; 424 msg.msg_controllen = sizeof(ubuf); 425 ubufs = nvq->ubufs; 426 atomic_inc(&ubufs->refcount); 427 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; 428 } else { 429 msg.msg_control = NULL; 430 ubufs = NULL; 431 } 432 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 433 err = sock->ops->sendmsg(NULL, sock, &msg, len); 434 if (unlikely(err < 0)) { 435 if (zcopy_used) { 436 vhost_net_ubuf_put(ubufs); 437 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) 438 % UIO_MAXIOV; 439 } 440 vhost_discard_vq_desc(vq, 1); 441 break; 442 } 443 if (err != len) 444 pr_debug("Truncated TX packet: " 445 " len %d != %zd\n", err, len); 446 if (!zcopy_used) 447 vhost_add_used_and_signal(&net->dev, vq, head, 0); 448 else 449 vhost_zerocopy_signal_used(net, vq); 450 total_len += len; 451 vhost_net_tx_packet(net); 452 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 453 vhost_poll_queue(&vq->poll); 454 break; 455 } 456 } 457 out: 458 mutex_unlock(&vq->mutex); 459 } 460 461 static int peek_head_len(struct sock *sk) 462 { 463 struct sk_buff *head; 464 int len = 0; 465 unsigned long flags; 466 467 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); 468 head = skb_peek(&sk->sk_receive_queue); 469 if (likely(head)) { 470 len = head->len; 471 if (vlan_tx_tag_present(head)) 472 len += VLAN_HLEN; 473 } 474 475 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); 476 return len; 477 } 478 479 /* This is a multi-buffer version of vhost_get_desc, that works if 480 * vq has read descriptors only. 481 * @vq - the relevant virtqueue 482 * @datalen - data length we'll be reading 483 * @iovcount - returned count of io vectors we fill 484 * @log - vhost log 485 * @log_num - log offset 486 * @quota - headcount quota, 1 for big buffer 487 * returns number of buffer heads allocated, negative on error 488 */ 489 static int get_rx_bufs(struct vhost_virtqueue *vq, 490 struct vring_used_elem *heads, 491 int datalen, 492 unsigned *iovcount, 493 struct vhost_log *log, 494 unsigned *log_num, 495 unsigned int quota) 496 { 497 unsigned int out, in; 498 int seg = 0; 499 int headcount = 0; 500 unsigned d; 501 int r, nlogs = 0; 502 503 while (datalen > 0 && headcount < quota) { 504 if (unlikely(seg >= UIO_MAXIOV)) { 505 r = -ENOBUFS; 506 goto err; 507 } 508 d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg, 509 ARRAY_SIZE(vq->iov) - seg, &out, 510 &in, log, log_num); 511 if (d == vq->num) { 512 r = 0; 513 goto err; 514 } 515 if (unlikely(out || in <= 0)) { 516 vq_err(vq, "unexpected descriptor format for RX: " 517 "out %d, in %d\n", out, in); 518 r = -EINVAL; 519 goto err; 520 } 521 if (unlikely(log)) { 522 nlogs += *log_num; 523 log += *log_num; 524 } 525 heads[headcount].id = d; 526 heads[headcount].len = iov_length(vq->iov + seg, in); 527 datalen -= heads[headcount].len; 528 ++headcount; 529 seg += in; 530 } 531 heads[headcount - 1].len += datalen; 532 *iovcount = seg; 533 if (unlikely(log)) 534 *log_num = nlogs; 535 return headcount; 536 err: 537 vhost_discard_vq_desc(vq, headcount); 538 return r; 539 } 540 541 /* Expects to be always run from workqueue - which acts as 542 * read-size critical section for our kind of RCU. */ 543 static void handle_rx(struct vhost_net *net) 544 { 545 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; 546 struct vhost_virtqueue *vq = &nvq->vq; 547 unsigned uninitialized_var(in), log; 548 struct vhost_log *vq_log; 549 struct msghdr msg = { 550 .msg_name = NULL, 551 .msg_namelen = 0, 552 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 553 .msg_controllen = 0, 554 .msg_iov = vq->iov, 555 .msg_flags = MSG_DONTWAIT, 556 }; 557 struct virtio_net_hdr_mrg_rxbuf hdr = { 558 .hdr.flags = 0, 559 .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE 560 }; 561 size_t total_len = 0; 562 int err, mergeable; 563 s16 headcount; 564 size_t vhost_hlen, sock_hlen; 565 size_t vhost_len, sock_len; 566 struct socket *sock; 567 568 mutex_lock(&vq->mutex); 569 sock = vq->private_data; 570 if (!sock) 571 goto out; 572 vhost_disable_notify(&net->dev, vq); 573 574 vhost_hlen = nvq->vhost_hlen; 575 sock_hlen = nvq->sock_hlen; 576 577 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? 578 vq->log : NULL; 579 mergeable = vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF); 580 581 while ((sock_len = peek_head_len(sock->sk))) { 582 sock_len += sock_hlen; 583 vhost_len = sock_len + vhost_hlen; 584 headcount = get_rx_bufs(vq, vq->heads, vhost_len, 585 &in, vq_log, &log, 586 likely(mergeable) ? UIO_MAXIOV : 1); 587 /* On error, stop handling until the next kick. */ 588 if (unlikely(headcount < 0)) 589 break; 590 /* OK, now we need to know about added descriptors. */ 591 if (!headcount) { 592 if (unlikely(vhost_enable_notify(&net->dev, vq))) { 593 /* They have slipped one in as we were 594 * doing that: check again. */ 595 vhost_disable_notify(&net->dev, vq); 596 continue; 597 } 598 /* Nothing new? Wait for eventfd to tell us 599 * they refilled. */ 600 break; 601 } 602 /* We don't need to be notified again. */ 603 if (unlikely((vhost_hlen))) 604 /* Skip header. TODO: support TSO. */ 605 move_iovec_hdr(vq->iov, nvq->hdr, vhost_hlen, in); 606 else 607 /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF: 608 * needed because recvmsg can modify msg_iov. */ 609 copy_iovec_hdr(vq->iov, nvq->hdr, sock_hlen, in); 610 msg.msg_iovlen = in; 611 err = sock->ops->recvmsg(NULL, sock, &msg, 612 sock_len, MSG_DONTWAIT | MSG_TRUNC); 613 /* Userspace might have consumed the packet meanwhile: 614 * it's not supposed to do this usually, but might be hard 615 * to prevent. Discard data we got (if any) and keep going. */ 616 if (unlikely(err != sock_len)) { 617 pr_debug("Discarded rx packet: " 618 " len %d, expected %zd\n", err, sock_len); 619 vhost_discard_vq_desc(vq, headcount); 620 continue; 621 } 622 if (unlikely(vhost_hlen) && 623 memcpy_toiovecend(nvq->hdr, (unsigned char *)&hdr, 0, 624 vhost_hlen)) { 625 vq_err(vq, "Unable to write vnet_hdr at addr %p\n", 626 vq->iov->iov_base); 627 break; 628 } 629 /* TODO: Should check and handle checksum. */ 630 if (likely(mergeable) && 631 memcpy_toiovecend(nvq->hdr, (unsigned char *)&headcount, 632 offsetof(typeof(hdr), num_buffers), 633 sizeof hdr.num_buffers)) { 634 vq_err(vq, "Failed num_buffers write"); 635 vhost_discard_vq_desc(vq, headcount); 636 break; 637 } 638 vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, 639 headcount); 640 if (unlikely(vq_log)) 641 vhost_log_write(vq, vq_log, log, vhost_len); 642 total_len += vhost_len; 643 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 644 vhost_poll_queue(&vq->poll); 645 break; 646 } 647 } 648 out: 649 mutex_unlock(&vq->mutex); 650 } 651 652 static void handle_tx_kick(struct vhost_work *work) 653 { 654 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 655 poll.work); 656 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 657 658 handle_tx(net); 659 } 660 661 static void handle_rx_kick(struct vhost_work *work) 662 { 663 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 664 poll.work); 665 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 666 667 handle_rx(net); 668 } 669 670 static void handle_tx_net(struct vhost_work *work) 671 { 672 struct vhost_net *net = container_of(work, struct vhost_net, 673 poll[VHOST_NET_VQ_TX].work); 674 handle_tx(net); 675 } 676 677 static void handle_rx_net(struct vhost_work *work) 678 { 679 struct vhost_net *net = container_of(work, struct vhost_net, 680 poll[VHOST_NET_VQ_RX].work); 681 handle_rx(net); 682 } 683 684 static int vhost_net_open(struct inode *inode, struct file *f) 685 { 686 struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL); 687 struct vhost_dev *dev; 688 struct vhost_virtqueue **vqs; 689 int i; 690 691 if (!n) 692 return -ENOMEM; 693 vqs = kmalloc(VHOST_NET_VQ_MAX * sizeof(*vqs), GFP_KERNEL); 694 if (!vqs) { 695 kfree(n); 696 return -ENOMEM; 697 } 698 699 dev = &n->dev; 700 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; 701 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; 702 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; 703 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; 704 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 705 n->vqs[i].ubufs = NULL; 706 n->vqs[i].ubuf_info = NULL; 707 n->vqs[i].upend_idx = 0; 708 n->vqs[i].done_idx = 0; 709 n->vqs[i].vhost_hlen = 0; 710 n->vqs[i].sock_hlen = 0; 711 } 712 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX); 713 714 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev); 715 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev); 716 717 f->private_data = n; 718 719 return 0; 720 } 721 722 static void vhost_net_disable_vq(struct vhost_net *n, 723 struct vhost_virtqueue *vq) 724 { 725 struct vhost_net_virtqueue *nvq = 726 container_of(vq, struct vhost_net_virtqueue, vq); 727 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 728 if (!vq->private_data) 729 return; 730 vhost_poll_stop(poll); 731 } 732 733 static int vhost_net_enable_vq(struct vhost_net *n, 734 struct vhost_virtqueue *vq) 735 { 736 struct vhost_net_virtqueue *nvq = 737 container_of(vq, struct vhost_net_virtqueue, vq); 738 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 739 struct socket *sock; 740 741 sock = vq->private_data; 742 if (!sock) 743 return 0; 744 745 return vhost_poll_start(poll, sock->file); 746 } 747 748 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 749 struct vhost_virtqueue *vq) 750 { 751 struct socket *sock; 752 753 mutex_lock(&vq->mutex); 754 sock = vq->private_data; 755 vhost_net_disable_vq(n, vq); 756 vq->private_data = NULL; 757 mutex_unlock(&vq->mutex); 758 return sock; 759 } 760 761 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 762 struct socket **rx_sock) 763 { 764 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); 765 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); 766 } 767 768 static void vhost_net_flush_vq(struct vhost_net *n, int index) 769 { 770 vhost_poll_flush(n->poll + index); 771 vhost_poll_flush(&n->vqs[index].vq.poll); 772 } 773 774 static void vhost_net_flush(struct vhost_net *n) 775 { 776 vhost_net_flush_vq(n, VHOST_NET_VQ_TX); 777 vhost_net_flush_vq(n, VHOST_NET_VQ_RX); 778 if (n->vqs[VHOST_NET_VQ_TX].ubufs) { 779 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 780 n->tx_flush = true; 781 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 782 /* Wait for all lower device DMAs done. */ 783 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); 784 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 785 n->tx_flush = false; 786 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); 787 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 788 } 789 } 790 791 static int vhost_net_release(struct inode *inode, struct file *f) 792 { 793 struct vhost_net *n = f->private_data; 794 struct socket *tx_sock; 795 struct socket *rx_sock; 796 797 vhost_net_stop(n, &tx_sock, &rx_sock); 798 vhost_net_flush(n); 799 vhost_dev_stop(&n->dev); 800 vhost_dev_cleanup(&n->dev, false); 801 vhost_net_vq_reset(n); 802 if (tx_sock) 803 fput(tx_sock->file); 804 if (rx_sock) 805 fput(rx_sock->file); 806 /* Make sure no callbacks are outstanding */ 807 synchronize_rcu_bh(); 808 /* We do an extra flush before freeing memory, 809 * since jobs can re-queue themselves. */ 810 vhost_net_flush(n); 811 kfree(n->dev.vqs); 812 kfree(n); 813 return 0; 814 } 815 816 static struct socket *get_raw_socket(int fd) 817 { 818 struct { 819 struct sockaddr_ll sa; 820 char buf[MAX_ADDR_LEN]; 821 } uaddr; 822 int uaddr_len = sizeof uaddr, r; 823 struct socket *sock = sockfd_lookup(fd, &r); 824 825 if (!sock) 826 return ERR_PTR(-ENOTSOCK); 827 828 /* Parameter checking */ 829 if (sock->sk->sk_type != SOCK_RAW) { 830 r = -ESOCKTNOSUPPORT; 831 goto err; 832 } 833 834 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 835 &uaddr_len, 0); 836 if (r) 837 goto err; 838 839 if (uaddr.sa.sll_family != AF_PACKET) { 840 r = -EPFNOSUPPORT; 841 goto err; 842 } 843 return sock; 844 err: 845 fput(sock->file); 846 return ERR_PTR(r); 847 } 848 849 static struct socket *get_tap_socket(int fd) 850 { 851 struct file *file = fget(fd); 852 struct socket *sock; 853 854 if (!file) 855 return ERR_PTR(-EBADF); 856 sock = tun_get_socket(file); 857 if (!IS_ERR(sock)) 858 return sock; 859 sock = macvtap_get_socket(file); 860 if (IS_ERR(sock)) 861 fput(file); 862 return sock; 863 } 864 865 static struct socket *get_socket(int fd) 866 { 867 struct socket *sock; 868 869 /* special case to disable backend */ 870 if (fd == -1) 871 return NULL; 872 sock = get_raw_socket(fd); 873 if (!IS_ERR(sock)) 874 return sock; 875 sock = get_tap_socket(fd); 876 if (!IS_ERR(sock)) 877 return sock; 878 return ERR_PTR(-ENOTSOCK); 879 } 880 881 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 882 { 883 struct socket *sock, *oldsock; 884 struct vhost_virtqueue *vq; 885 struct vhost_net_virtqueue *nvq; 886 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; 887 int r; 888 889 mutex_lock(&n->dev.mutex); 890 r = vhost_dev_check_owner(&n->dev); 891 if (r) 892 goto err; 893 894 if (index >= VHOST_NET_VQ_MAX) { 895 r = -ENOBUFS; 896 goto err; 897 } 898 vq = &n->vqs[index].vq; 899 nvq = &n->vqs[index]; 900 mutex_lock(&vq->mutex); 901 902 /* Verify that ring has been setup correctly. */ 903 if (!vhost_vq_access_ok(vq)) { 904 r = -EFAULT; 905 goto err_vq; 906 } 907 sock = get_socket(fd); 908 if (IS_ERR(sock)) { 909 r = PTR_ERR(sock); 910 goto err_vq; 911 } 912 913 /* start polling new socket */ 914 oldsock = vq->private_data; 915 if (sock != oldsock) { 916 ubufs = vhost_net_ubuf_alloc(vq, 917 sock && vhost_sock_zcopy(sock)); 918 if (IS_ERR(ubufs)) { 919 r = PTR_ERR(ubufs); 920 goto err_ubufs; 921 } 922 923 vhost_net_disable_vq(n, vq); 924 vq->private_data = sock; 925 r = vhost_init_used(vq); 926 if (r) 927 goto err_used; 928 r = vhost_net_enable_vq(n, vq); 929 if (r) 930 goto err_used; 931 932 oldubufs = nvq->ubufs; 933 nvq->ubufs = ubufs; 934 935 n->tx_packets = 0; 936 n->tx_zcopy_err = 0; 937 n->tx_flush = false; 938 } 939 940 mutex_unlock(&vq->mutex); 941 942 if (oldubufs) { 943 vhost_net_ubuf_put_wait_and_free(oldubufs); 944 mutex_lock(&vq->mutex); 945 vhost_zerocopy_signal_used(n, vq); 946 mutex_unlock(&vq->mutex); 947 } 948 949 if (oldsock) { 950 vhost_net_flush_vq(n, index); 951 fput(oldsock->file); 952 } 953 954 mutex_unlock(&n->dev.mutex); 955 return 0; 956 957 err_used: 958 vq->private_data = oldsock; 959 vhost_net_enable_vq(n, vq); 960 if (ubufs) 961 vhost_net_ubuf_put_wait_and_free(ubufs); 962 err_ubufs: 963 fput(sock->file); 964 err_vq: 965 mutex_unlock(&vq->mutex); 966 err: 967 mutex_unlock(&n->dev.mutex); 968 return r; 969 } 970 971 static long vhost_net_reset_owner(struct vhost_net *n) 972 { 973 struct socket *tx_sock = NULL; 974 struct socket *rx_sock = NULL; 975 long err; 976 struct vhost_memory *memory; 977 978 mutex_lock(&n->dev.mutex); 979 err = vhost_dev_check_owner(&n->dev); 980 if (err) 981 goto done; 982 memory = vhost_dev_reset_owner_prepare(); 983 if (!memory) { 984 err = -ENOMEM; 985 goto done; 986 } 987 vhost_net_stop(n, &tx_sock, &rx_sock); 988 vhost_net_flush(n); 989 vhost_dev_reset_owner(&n->dev, memory); 990 vhost_net_vq_reset(n); 991 done: 992 mutex_unlock(&n->dev.mutex); 993 if (tx_sock) 994 fput(tx_sock->file); 995 if (rx_sock) 996 fput(rx_sock->file); 997 return err; 998 } 999 1000 static int vhost_net_set_features(struct vhost_net *n, u64 features) 1001 { 1002 size_t vhost_hlen, sock_hlen, hdr_len; 1003 int i; 1004 1005 hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? 1006 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 1007 sizeof(struct virtio_net_hdr); 1008 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 1009 /* vhost provides vnet_hdr */ 1010 vhost_hlen = hdr_len; 1011 sock_hlen = 0; 1012 } else { 1013 /* socket provides vnet_hdr */ 1014 vhost_hlen = 0; 1015 sock_hlen = hdr_len; 1016 } 1017 mutex_lock(&n->dev.mutex); 1018 if ((features & (1 << VHOST_F_LOG_ALL)) && 1019 !vhost_log_access_ok(&n->dev)) { 1020 mutex_unlock(&n->dev.mutex); 1021 return -EFAULT; 1022 } 1023 n->dev.acked_features = features; 1024 smp_wmb(); 1025 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1026 mutex_lock(&n->vqs[i].vq.mutex); 1027 n->vqs[i].vhost_hlen = vhost_hlen; 1028 n->vqs[i].sock_hlen = sock_hlen; 1029 mutex_unlock(&n->vqs[i].vq.mutex); 1030 } 1031 vhost_net_flush(n); 1032 mutex_unlock(&n->dev.mutex); 1033 return 0; 1034 } 1035 1036 static long vhost_net_set_owner(struct vhost_net *n) 1037 { 1038 int r; 1039 1040 mutex_lock(&n->dev.mutex); 1041 if (vhost_dev_has_owner(&n->dev)) { 1042 r = -EBUSY; 1043 goto out; 1044 } 1045 r = vhost_net_set_ubuf_info(n); 1046 if (r) 1047 goto out; 1048 r = vhost_dev_set_owner(&n->dev); 1049 if (r) 1050 vhost_net_clear_ubuf_info(n); 1051 vhost_net_flush(n); 1052 out: 1053 mutex_unlock(&n->dev.mutex); 1054 return r; 1055 } 1056 1057 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 1058 unsigned long arg) 1059 { 1060 struct vhost_net *n = f->private_data; 1061 void __user *argp = (void __user *)arg; 1062 u64 __user *featurep = argp; 1063 struct vhost_vring_file backend; 1064 u64 features; 1065 int r; 1066 1067 switch (ioctl) { 1068 case VHOST_NET_SET_BACKEND: 1069 if (copy_from_user(&backend, argp, sizeof backend)) 1070 return -EFAULT; 1071 return vhost_net_set_backend(n, backend.index, backend.fd); 1072 case VHOST_GET_FEATURES: 1073 features = VHOST_NET_FEATURES; 1074 if (copy_to_user(featurep, &features, sizeof features)) 1075 return -EFAULT; 1076 return 0; 1077 case VHOST_SET_FEATURES: 1078 if (copy_from_user(&features, featurep, sizeof features)) 1079 return -EFAULT; 1080 if (features & ~VHOST_NET_FEATURES) 1081 return -EOPNOTSUPP; 1082 return vhost_net_set_features(n, features); 1083 case VHOST_RESET_OWNER: 1084 return vhost_net_reset_owner(n); 1085 case VHOST_SET_OWNER: 1086 return vhost_net_set_owner(n); 1087 default: 1088 mutex_lock(&n->dev.mutex); 1089 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 1090 if (r == -ENOIOCTLCMD) 1091 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 1092 else 1093 vhost_net_flush(n); 1094 mutex_unlock(&n->dev.mutex); 1095 return r; 1096 } 1097 } 1098 1099 #ifdef CONFIG_COMPAT 1100 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, 1101 unsigned long arg) 1102 { 1103 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); 1104 } 1105 #endif 1106 1107 static const struct file_operations vhost_net_fops = { 1108 .owner = THIS_MODULE, 1109 .release = vhost_net_release, 1110 .unlocked_ioctl = vhost_net_ioctl, 1111 #ifdef CONFIG_COMPAT 1112 .compat_ioctl = vhost_net_compat_ioctl, 1113 #endif 1114 .open = vhost_net_open, 1115 .llseek = noop_llseek, 1116 }; 1117 1118 static struct miscdevice vhost_net_misc = { 1119 .minor = VHOST_NET_MINOR, 1120 .name = "vhost-net", 1121 .fops = &vhost_net_fops, 1122 }; 1123 1124 static int vhost_net_init(void) 1125 { 1126 if (experimental_zcopytx) 1127 vhost_net_enable_zcopy(VHOST_NET_VQ_TX); 1128 return misc_register(&vhost_net_misc); 1129 } 1130 module_init(vhost_net_init); 1131 1132 static void vhost_net_exit(void) 1133 { 1134 misc_deregister(&vhost_net_misc); 1135 } 1136 module_exit(vhost_net_exit); 1137 1138 MODULE_VERSION("0.0.1"); 1139 MODULE_LICENSE("GPL v2"); 1140 MODULE_AUTHOR("Michael S. Tsirkin"); 1141 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1142 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1143 MODULE_ALIAS("devname:vhost-net"); 1144