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 r = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg, 509 ARRAY_SIZE(vq->iov) - seg, &out, 510 &in, log, log_num); 511 if (unlikely(r < 0)) 512 goto err; 513 514 d = r; 515 if (d == vq->num) { 516 r = 0; 517 goto err; 518 } 519 if (unlikely(out || in <= 0)) { 520 vq_err(vq, "unexpected descriptor format for RX: " 521 "out %d, in %d\n", out, in); 522 r = -EINVAL; 523 goto err; 524 } 525 if (unlikely(log)) { 526 nlogs += *log_num; 527 log += *log_num; 528 } 529 heads[headcount].id = d; 530 heads[headcount].len = iov_length(vq->iov + seg, in); 531 datalen -= heads[headcount].len; 532 ++headcount; 533 seg += in; 534 } 535 heads[headcount - 1].len += datalen; 536 *iovcount = seg; 537 if (unlikely(log)) 538 *log_num = nlogs; 539 540 /* Detect overrun */ 541 if (unlikely(datalen > 0)) { 542 r = UIO_MAXIOV + 1; 543 goto err; 544 } 545 return headcount; 546 err: 547 vhost_discard_vq_desc(vq, headcount); 548 return r; 549 } 550 551 /* Expects to be always run from workqueue - which acts as 552 * read-size critical section for our kind of RCU. */ 553 static void handle_rx(struct vhost_net *net) 554 { 555 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; 556 struct vhost_virtqueue *vq = &nvq->vq; 557 unsigned uninitialized_var(in), log; 558 struct vhost_log *vq_log; 559 struct msghdr msg = { 560 .msg_name = NULL, 561 .msg_namelen = 0, 562 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 563 .msg_controllen = 0, 564 .msg_iov = vq->iov, 565 .msg_flags = MSG_DONTWAIT, 566 }; 567 struct virtio_net_hdr_mrg_rxbuf hdr = { 568 .hdr.flags = 0, 569 .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE 570 }; 571 size_t total_len = 0; 572 int err, mergeable; 573 s16 headcount; 574 size_t vhost_hlen, sock_hlen; 575 size_t vhost_len, sock_len; 576 struct socket *sock; 577 578 mutex_lock(&vq->mutex); 579 sock = vq->private_data; 580 if (!sock) 581 goto out; 582 vhost_disable_notify(&net->dev, vq); 583 584 vhost_hlen = nvq->vhost_hlen; 585 sock_hlen = nvq->sock_hlen; 586 587 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? 588 vq->log : NULL; 589 mergeable = vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF); 590 591 while ((sock_len = peek_head_len(sock->sk))) { 592 sock_len += sock_hlen; 593 vhost_len = sock_len + vhost_hlen; 594 headcount = get_rx_bufs(vq, vq->heads, vhost_len, 595 &in, vq_log, &log, 596 likely(mergeable) ? UIO_MAXIOV : 1); 597 /* On error, stop handling until the next kick. */ 598 if (unlikely(headcount < 0)) 599 break; 600 /* On overrun, truncate and discard */ 601 if (unlikely(headcount > UIO_MAXIOV)) { 602 msg.msg_iovlen = 1; 603 err = sock->ops->recvmsg(NULL, sock, &msg, 604 1, MSG_DONTWAIT | MSG_TRUNC); 605 pr_debug("Discarded rx packet: len %zd\n", sock_len); 606 continue; 607 } 608 /* OK, now we need to know about added descriptors. */ 609 if (!headcount) { 610 if (unlikely(vhost_enable_notify(&net->dev, vq))) { 611 /* They have slipped one in as we were 612 * doing that: check again. */ 613 vhost_disable_notify(&net->dev, vq); 614 continue; 615 } 616 /* Nothing new? Wait for eventfd to tell us 617 * they refilled. */ 618 break; 619 } 620 /* We don't need to be notified again. */ 621 if (unlikely((vhost_hlen))) 622 /* Skip header. TODO: support TSO. */ 623 move_iovec_hdr(vq->iov, nvq->hdr, vhost_hlen, in); 624 else 625 /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF: 626 * needed because recvmsg can modify msg_iov. */ 627 copy_iovec_hdr(vq->iov, nvq->hdr, sock_hlen, in); 628 msg.msg_iovlen = in; 629 err = sock->ops->recvmsg(NULL, sock, &msg, 630 sock_len, MSG_DONTWAIT | MSG_TRUNC); 631 /* Userspace might have consumed the packet meanwhile: 632 * it's not supposed to do this usually, but might be hard 633 * to prevent. Discard data we got (if any) and keep going. */ 634 if (unlikely(err != sock_len)) { 635 pr_debug("Discarded rx packet: " 636 " len %d, expected %zd\n", err, sock_len); 637 vhost_discard_vq_desc(vq, headcount); 638 continue; 639 } 640 if (unlikely(vhost_hlen) && 641 memcpy_toiovecend(nvq->hdr, (unsigned char *)&hdr, 0, 642 vhost_hlen)) { 643 vq_err(vq, "Unable to write vnet_hdr at addr %p\n", 644 vq->iov->iov_base); 645 break; 646 } 647 /* TODO: Should check and handle checksum. */ 648 if (likely(mergeable) && 649 memcpy_toiovecend(nvq->hdr, (unsigned char *)&headcount, 650 offsetof(typeof(hdr), num_buffers), 651 sizeof hdr.num_buffers)) { 652 vq_err(vq, "Failed num_buffers write"); 653 vhost_discard_vq_desc(vq, headcount); 654 break; 655 } 656 vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, 657 headcount); 658 if (unlikely(vq_log)) 659 vhost_log_write(vq, vq_log, log, vhost_len); 660 total_len += vhost_len; 661 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 662 vhost_poll_queue(&vq->poll); 663 break; 664 } 665 } 666 out: 667 mutex_unlock(&vq->mutex); 668 } 669 670 static void handle_tx_kick(struct vhost_work *work) 671 { 672 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 673 poll.work); 674 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 675 676 handle_tx(net); 677 } 678 679 static void handle_rx_kick(struct vhost_work *work) 680 { 681 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 682 poll.work); 683 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 684 685 handle_rx(net); 686 } 687 688 static void handle_tx_net(struct vhost_work *work) 689 { 690 struct vhost_net *net = container_of(work, struct vhost_net, 691 poll[VHOST_NET_VQ_TX].work); 692 handle_tx(net); 693 } 694 695 static void handle_rx_net(struct vhost_work *work) 696 { 697 struct vhost_net *net = container_of(work, struct vhost_net, 698 poll[VHOST_NET_VQ_RX].work); 699 handle_rx(net); 700 } 701 702 static int vhost_net_open(struct inode *inode, struct file *f) 703 { 704 struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL); 705 struct vhost_dev *dev; 706 struct vhost_virtqueue **vqs; 707 int i; 708 709 if (!n) 710 return -ENOMEM; 711 vqs = kmalloc(VHOST_NET_VQ_MAX * sizeof(*vqs), GFP_KERNEL); 712 if (!vqs) { 713 kfree(n); 714 return -ENOMEM; 715 } 716 717 dev = &n->dev; 718 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; 719 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; 720 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; 721 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; 722 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 723 n->vqs[i].ubufs = NULL; 724 n->vqs[i].ubuf_info = NULL; 725 n->vqs[i].upend_idx = 0; 726 n->vqs[i].done_idx = 0; 727 n->vqs[i].vhost_hlen = 0; 728 n->vqs[i].sock_hlen = 0; 729 } 730 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX); 731 732 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev); 733 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev); 734 735 f->private_data = n; 736 737 return 0; 738 } 739 740 static void vhost_net_disable_vq(struct vhost_net *n, 741 struct vhost_virtqueue *vq) 742 { 743 struct vhost_net_virtqueue *nvq = 744 container_of(vq, struct vhost_net_virtqueue, vq); 745 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 746 if (!vq->private_data) 747 return; 748 vhost_poll_stop(poll); 749 } 750 751 static int vhost_net_enable_vq(struct vhost_net *n, 752 struct vhost_virtqueue *vq) 753 { 754 struct vhost_net_virtqueue *nvq = 755 container_of(vq, struct vhost_net_virtqueue, vq); 756 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 757 struct socket *sock; 758 759 sock = vq->private_data; 760 if (!sock) 761 return 0; 762 763 return vhost_poll_start(poll, sock->file); 764 } 765 766 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 767 struct vhost_virtqueue *vq) 768 { 769 struct socket *sock; 770 771 mutex_lock(&vq->mutex); 772 sock = vq->private_data; 773 vhost_net_disable_vq(n, vq); 774 vq->private_data = NULL; 775 mutex_unlock(&vq->mutex); 776 return sock; 777 } 778 779 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 780 struct socket **rx_sock) 781 { 782 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); 783 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); 784 } 785 786 static void vhost_net_flush_vq(struct vhost_net *n, int index) 787 { 788 vhost_poll_flush(n->poll + index); 789 vhost_poll_flush(&n->vqs[index].vq.poll); 790 } 791 792 static void vhost_net_flush(struct vhost_net *n) 793 { 794 vhost_net_flush_vq(n, VHOST_NET_VQ_TX); 795 vhost_net_flush_vq(n, VHOST_NET_VQ_RX); 796 if (n->vqs[VHOST_NET_VQ_TX].ubufs) { 797 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 798 n->tx_flush = true; 799 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 800 /* Wait for all lower device DMAs done. */ 801 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); 802 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 803 n->tx_flush = false; 804 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); 805 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 806 } 807 } 808 809 static int vhost_net_release(struct inode *inode, struct file *f) 810 { 811 struct vhost_net *n = f->private_data; 812 struct socket *tx_sock; 813 struct socket *rx_sock; 814 815 vhost_net_stop(n, &tx_sock, &rx_sock); 816 vhost_net_flush(n); 817 vhost_dev_stop(&n->dev); 818 vhost_dev_cleanup(&n->dev, false); 819 vhost_net_vq_reset(n); 820 if (tx_sock) 821 sockfd_put(tx_sock); 822 if (rx_sock) 823 sockfd_put(rx_sock); 824 /* Make sure no callbacks are outstanding */ 825 synchronize_rcu_bh(); 826 /* We do an extra flush before freeing memory, 827 * since jobs can re-queue themselves. */ 828 vhost_net_flush(n); 829 kfree(n->dev.vqs); 830 kfree(n); 831 return 0; 832 } 833 834 static struct socket *get_raw_socket(int fd) 835 { 836 struct { 837 struct sockaddr_ll sa; 838 char buf[MAX_ADDR_LEN]; 839 } uaddr; 840 int uaddr_len = sizeof uaddr, r; 841 struct socket *sock = sockfd_lookup(fd, &r); 842 843 if (!sock) 844 return ERR_PTR(-ENOTSOCK); 845 846 /* Parameter checking */ 847 if (sock->sk->sk_type != SOCK_RAW) { 848 r = -ESOCKTNOSUPPORT; 849 goto err; 850 } 851 852 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 853 &uaddr_len, 0); 854 if (r) 855 goto err; 856 857 if (uaddr.sa.sll_family != AF_PACKET) { 858 r = -EPFNOSUPPORT; 859 goto err; 860 } 861 return sock; 862 err: 863 sockfd_put(sock); 864 return ERR_PTR(r); 865 } 866 867 static struct socket *get_tap_socket(int fd) 868 { 869 struct file *file = fget(fd); 870 struct socket *sock; 871 872 if (!file) 873 return ERR_PTR(-EBADF); 874 sock = tun_get_socket(file); 875 if (!IS_ERR(sock)) 876 return sock; 877 sock = macvtap_get_socket(file); 878 if (IS_ERR(sock)) 879 fput(file); 880 return sock; 881 } 882 883 static struct socket *get_socket(int fd) 884 { 885 struct socket *sock; 886 887 /* special case to disable backend */ 888 if (fd == -1) 889 return NULL; 890 sock = get_raw_socket(fd); 891 if (!IS_ERR(sock)) 892 return sock; 893 sock = get_tap_socket(fd); 894 if (!IS_ERR(sock)) 895 return sock; 896 return ERR_PTR(-ENOTSOCK); 897 } 898 899 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 900 { 901 struct socket *sock, *oldsock; 902 struct vhost_virtqueue *vq; 903 struct vhost_net_virtqueue *nvq; 904 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; 905 int r; 906 907 mutex_lock(&n->dev.mutex); 908 r = vhost_dev_check_owner(&n->dev); 909 if (r) 910 goto err; 911 912 if (index >= VHOST_NET_VQ_MAX) { 913 r = -ENOBUFS; 914 goto err; 915 } 916 vq = &n->vqs[index].vq; 917 nvq = &n->vqs[index]; 918 mutex_lock(&vq->mutex); 919 920 /* Verify that ring has been setup correctly. */ 921 if (!vhost_vq_access_ok(vq)) { 922 r = -EFAULT; 923 goto err_vq; 924 } 925 sock = get_socket(fd); 926 if (IS_ERR(sock)) { 927 r = PTR_ERR(sock); 928 goto err_vq; 929 } 930 931 /* start polling new socket */ 932 oldsock = vq->private_data; 933 if (sock != oldsock) { 934 ubufs = vhost_net_ubuf_alloc(vq, 935 sock && vhost_sock_zcopy(sock)); 936 if (IS_ERR(ubufs)) { 937 r = PTR_ERR(ubufs); 938 goto err_ubufs; 939 } 940 941 vhost_net_disable_vq(n, vq); 942 vq->private_data = sock; 943 r = vhost_init_used(vq); 944 if (r) 945 goto err_used; 946 r = vhost_net_enable_vq(n, vq); 947 if (r) 948 goto err_used; 949 950 oldubufs = nvq->ubufs; 951 nvq->ubufs = ubufs; 952 953 n->tx_packets = 0; 954 n->tx_zcopy_err = 0; 955 n->tx_flush = false; 956 } 957 958 mutex_unlock(&vq->mutex); 959 960 if (oldubufs) { 961 vhost_net_ubuf_put_wait_and_free(oldubufs); 962 mutex_lock(&vq->mutex); 963 vhost_zerocopy_signal_used(n, vq); 964 mutex_unlock(&vq->mutex); 965 } 966 967 if (oldsock) { 968 vhost_net_flush_vq(n, index); 969 sockfd_put(oldsock); 970 } 971 972 mutex_unlock(&n->dev.mutex); 973 return 0; 974 975 err_used: 976 vq->private_data = oldsock; 977 vhost_net_enable_vq(n, vq); 978 if (ubufs) 979 vhost_net_ubuf_put_wait_and_free(ubufs); 980 err_ubufs: 981 sockfd_put(sock); 982 err_vq: 983 mutex_unlock(&vq->mutex); 984 err: 985 mutex_unlock(&n->dev.mutex); 986 return r; 987 } 988 989 static long vhost_net_reset_owner(struct vhost_net *n) 990 { 991 struct socket *tx_sock = NULL; 992 struct socket *rx_sock = NULL; 993 long err; 994 struct vhost_memory *memory; 995 996 mutex_lock(&n->dev.mutex); 997 err = vhost_dev_check_owner(&n->dev); 998 if (err) 999 goto done; 1000 memory = vhost_dev_reset_owner_prepare(); 1001 if (!memory) { 1002 err = -ENOMEM; 1003 goto done; 1004 } 1005 vhost_net_stop(n, &tx_sock, &rx_sock); 1006 vhost_net_flush(n); 1007 vhost_dev_reset_owner(&n->dev, memory); 1008 vhost_net_vq_reset(n); 1009 done: 1010 mutex_unlock(&n->dev.mutex); 1011 if (tx_sock) 1012 sockfd_put(tx_sock); 1013 if (rx_sock) 1014 sockfd_put(rx_sock); 1015 return err; 1016 } 1017 1018 static int vhost_net_set_features(struct vhost_net *n, u64 features) 1019 { 1020 size_t vhost_hlen, sock_hlen, hdr_len; 1021 int i; 1022 1023 hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? 1024 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 1025 sizeof(struct virtio_net_hdr); 1026 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 1027 /* vhost provides vnet_hdr */ 1028 vhost_hlen = hdr_len; 1029 sock_hlen = 0; 1030 } else { 1031 /* socket provides vnet_hdr */ 1032 vhost_hlen = 0; 1033 sock_hlen = hdr_len; 1034 } 1035 mutex_lock(&n->dev.mutex); 1036 if ((features & (1 << VHOST_F_LOG_ALL)) && 1037 !vhost_log_access_ok(&n->dev)) { 1038 mutex_unlock(&n->dev.mutex); 1039 return -EFAULT; 1040 } 1041 n->dev.acked_features = features; 1042 smp_wmb(); 1043 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1044 mutex_lock(&n->vqs[i].vq.mutex); 1045 n->vqs[i].vhost_hlen = vhost_hlen; 1046 n->vqs[i].sock_hlen = sock_hlen; 1047 mutex_unlock(&n->vqs[i].vq.mutex); 1048 } 1049 vhost_net_flush(n); 1050 mutex_unlock(&n->dev.mutex); 1051 return 0; 1052 } 1053 1054 static long vhost_net_set_owner(struct vhost_net *n) 1055 { 1056 int r; 1057 1058 mutex_lock(&n->dev.mutex); 1059 if (vhost_dev_has_owner(&n->dev)) { 1060 r = -EBUSY; 1061 goto out; 1062 } 1063 r = vhost_net_set_ubuf_info(n); 1064 if (r) 1065 goto out; 1066 r = vhost_dev_set_owner(&n->dev); 1067 if (r) 1068 vhost_net_clear_ubuf_info(n); 1069 vhost_net_flush(n); 1070 out: 1071 mutex_unlock(&n->dev.mutex); 1072 return r; 1073 } 1074 1075 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 1076 unsigned long arg) 1077 { 1078 struct vhost_net *n = f->private_data; 1079 void __user *argp = (void __user *)arg; 1080 u64 __user *featurep = argp; 1081 struct vhost_vring_file backend; 1082 u64 features; 1083 int r; 1084 1085 switch (ioctl) { 1086 case VHOST_NET_SET_BACKEND: 1087 if (copy_from_user(&backend, argp, sizeof backend)) 1088 return -EFAULT; 1089 return vhost_net_set_backend(n, backend.index, backend.fd); 1090 case VHOST_GET_FEATURES: 1091 features = VHOST_NET_FEATURES; 1092 if (copy_to_user(featurep, &features, sizeof features)) 1093 return -EFAULT; 1094 return 0; 1095 case VHOST_SET_FEATURES: 1096 if (copy_from_user(&features, featurep, sizeof features)) 1097 return -EFAULT; 1098 if (features & ~VHOST_NET_FEATURES) 1099 return -EOPNOTSUPP; 1100 return vhost_net_set_features(n, features); 1101 case VHOST_RESET_OWNER: 1102 return vhost_net_reset_owner(n); 1103 case VHOST_SET_OWNER: 1104 return vhost_net_set_owner(n); 1105 default: 1106 mutex_lock(&n->dev.mutex); 1107 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 1108 if (r == -ENOIOCTLCMD) 1109 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 1110 else 1111 vhost_net_flush(n); 1112 mutex_unlock(&n->dev.mutex); 1113 return r; 1114 } 1115 } 1116 1117 #ifdef CONFIG_COMPAT 1118 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, 1119 unsigned long arg) 1120 { 1121 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); 1122 } 1123 #endif 1124 1125 static const struct file_operations vhost_net_fops = { 1126 .owner = THIS_MODULE, 1127 .release = vhost_net_release, 1128 .unlocked_ioctl = vhost_net_ioctl, 1129 #ifdef CONFIG_COMPAT 1130 .compat_ioctl = vhost_net_compat_ioctl, 1131 #endif 1132 .open = vhost_net_open, 1133 .llseek = noop_llseek, 1134 }; 1135 1136 static struct miscdevice vhost_net_misc = { 1137 .minor = VHOST_NET_MINOR, 1138 .name = "vhost-net", 1139 .fops = &vhost_net_fops, 1140 }; 1141 1142 static int vhost_net_init(void) 1143 { 1144 if (experimental_zcopytx) 1145 vhost_net_enable_zcopy(VHOST_NET_VQ_TX); 1146 return misc_register(&vhost_net_misc); 1147 } 1148 module_init(vhost_net_init); 1149 1150 static void vhost_net_exit(void) 1151 { 1152 misc_deregister(&vhost_net_misc); 1153 } 1154 module_exit(vhost_net_exit); 1155 1156 MODULE_VERSION("0.0.1"); 1157 MODULE_LICENSE("GPL v2"); 1158 MODULE_AUTHOR("Michael S. Tsirkin"); 1159 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1160 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1161 MODULE_ALIAS("devname:vhost-net"); 1162