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 #include <linux/vmalloc.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 ((__force __virtio32)3) 52 /* Lower device DMA done */ 53 #define VHOST_DMA_DONE_LEN ((__force __virtio32)2) 54 /* Lower device DMA in progress */ 55 #define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) 56 /* Buffer unused */ 57 #define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) 58 59 #define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) 60 61 enum { 62 VHOST_NET_FEATURES = VHOST_FEATURES | 63 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | 64 (1ULL << VIRTIO_NET_F_MRG_RXBUF) 65 }; 66 67 enum { 68 VHOST_NET_VQ_RX = 0, 69 VHOST_NET_VQ_TX = 1, 70 VHOST_NET_VQ_MAX = 2, 71 }; 72 73 struct vhost_net_ubuf_ref { 74 /* refcount follows semantics similar to kref: 75 * 0: object is released 76 * 1: no outstanding ubufs 77 * >1: outstanding ubufs 78 */ 79 atomic_t refcount; 80 wait_queue_head_t wait; 81 struct vhost_virtqueue *vq; 82 }; 83 84 struct vhost_net_virtqueue { 85 struct vhost_virtqueue vq; 86 size_t vhost_hlen; 87 size_t sock_hlen; 88 /* vhost zerocopy support fields below: */ 89 /* last used idx for outstanding DMA zerocopy buffers */ 90 int upend_idx; 91 /* first used idx for DMA done zerocopy buffers */ 92 int done_idx; 93 /* an array of userspace buffers info */ 94 struct ubuf_info *ubuf_info; 95 /* Reference counting for outstanding ubufs. 96 * Protected by vq mutex. Writers must also take device mutex. */ 97 struct vhost_net_ubuf_ref *ubufs; 98 }; 99 100 struct vhost_net { 101 struct vhost_dev dev; 102 struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX]; 103 struct vhost_poll poll[VHOST_NET_VQ_MAX]; 104 /* Number of TX recently submitted. 105 * Protected by tx vq lock. */ 106 unsigned tx_packets; 107 /* Number of times zerocopy TX recently failed. 108 * Protected by tx vq lock. */ 109 unsigned tx_zcopy_err; 110 /* Flush in progress. Protected by tx vq lock. */ 111 bool tx_flush; 112 }; 113 114 static unsigned vhost_net_zcopy_mask __read_mostly; 115 116 static void vhost_net_enable_zcopy(int vq) 117 { 118 vhost_net_zcopy_mask |= 0x1 << vq; 119 } 120 121 static struct vhost_net_ubuf_ref * 122 vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy) 123 { 124 struct vhost_net_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 atomic_set(&ubufs->refcount, 1); 132 init_waitqueue_head(&ubufs->wait); 133 ubufs->vq = vq; 134 return ubufs; 135 } 136 137 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs) 138 { 139 int r = atomic_sub_return(1, &ubufs->refcount); 140 if (unlikely(!r)) 141 wake_up(&ubufs->wait); 142 return r; 143 } 144 145 static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) 146 { 147 vhost_net_ubuf_put(ubufs); 148 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); 149 } 150 151 static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) 152 { 153 vhost_net_ubuf_put_and_wait(ubufs); 154 kfree(ubufs); 155 } 156 157 static void vhost_net_clear_ubuf_info(struct vhost_net *n) 158 { 159 int i; 160 161 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 162 kfree(n->vqs[i].ubuf_info); 163 n->vqs[i].ubuf_info = NULL; 164 } 165 } 166 167 static int vhost_net_set_ubuf_info(struct vhost_net *n) 168 { 169 bool zcopy; 170 int i; 171 172 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 173 zcopy = vhost_net_zcopy_mask & (0x1 << i); 174 if (!zcopy) 175 continue; 176 n->vqs[i].ubuf_info = kmalloc(sizeof(*n->vqs[i].ubuf_info) * 177 UIO_MAXIOV, GFP_KERNEL); 178 if (!n->vqs[i].ubuf_info) 179 goto err; 180 } 181 return 0; 182 183 err: 184 vhost_net_clear_ubuf_info(n); 185 return -ENOMEM; 186 } 187 188 static void vhost_net_vq_reset(struct vhost_net *n) 189 { 190 int i; 191 192 vhost_net_clear_ubuf_info(n); 193 194 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 195 n->vqs[i].done_idx = 0; 196 n->vqs[i].upend_idx = 0; 197 n->vqs[i].ubufs = NULL; 198 n->vqs[i].vhost_hlen = 0; 199 n->vqs[i].sock_hlen = 0; 200 } 201 202 } 203 204 static void vhost_net_tx_packet(struct vhost_net *net) 205 { 206 ++net->tx_packets; 207 if (net->tx_packets < 1024) 208 return; 209 net->tx_packets = 0; 210 net->tx_zcopy_err = 0; 211 } 212 213 static void vhost_net_tx_err(struct vhost_net *net) 214 { 215 ++net->tx_zcopy_err; 216 } 217 218 static bool vhost_net_tx_select_zcopy(struct vhost_net *net) 219 { 220 /* TX flush waits for outstanding DMAs to be done. 221 * Don't start new DMAs. 222 */ 223 return !net->tx_flush && 224 net->tx_packets / 64 >= net->tx_zcopy_err; 225 } 226 227 static bool vhost_sock_zcopy(struct socket *sock) 228 { 229 return unlikely(experimental_zcopytx) && 230 sock_flag(sock->sk, SOCK_ZEROCOPY); 231 } 232 233 /* In case of DMA done not in order in lower device driver for some reason. 234 * upend_idx is used to track end of used idx, done_idx is used to track head 235 * of used idx. Once lower device DMA done contiguously, we will signal KVM 236 * guest used idx. 237 */ 238 static void vhost_zerocopy_signal_used(struct vhost_net *net, 239 struct vhost_virtqueue *vq) 240 { 241 struct vhost_net_virtqueue *nvq = 242 container_of(vq, struct vhost_net_virtqueue, vq); 243 int i, add; 244 int j = 0; 245 246 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { 247 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) 248 vhost_net_tx_err(net); 249 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { 250 vq->heads[i].len = VHOST_DMA_CLEAR_LEN; 251 ++j; 252 } else 253 break; 254 } 255 while (j) { 256 add = min(UIO_MAXIOV - nvq->done_idx, j); 257 vhost_add_used_and_signal_n(vq->dev, vq, 258 &vq->heads[nvq->done_idx], add); 259 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; 260 j -= add; 261 } 262 } 263 264 static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) 265 { 266 struct vhost_net_ubuf_ref *ubufs = ubuf->ctx; 267 struct vhost_virtqueue *vq = ubufs->vq; 268 int cnt; 269 270 rcu_read_lock_bh(); 271 272 /* set len to mark this desc buffers done DMA */ 273 vq->heads[ubuf->desc].len = success ? 274 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; 275 cnt = vhost_net_ubuf_put(ubufs); 276 277 /* 278 * Trigger polling thread if guest stopped submitting new buffers: 279 * in this case, the refcount after decrement will eventually reach 1. 280 * We also trigger polling periodically after each 16 packets 281 * (the value 16 here is more or less arbitrary, it's tuned to trigger 282 * less than 10% of times). 283 */ 284 if (cnt <= 1 || !(cnt % 16)) 285 vhost_poll_queue(&vq->poll); 286 287 rcu_read_unlock_bh(); 288 } 289 290 static inline unsigned long busy_clock(void) 291 { 292 return local_clock() >> 10; 293 } 294 295 static bool vhost_can_busy_poll(struct vhost_dev *dev, 296 unsigned long endtime) 297 { 298 return likely(!need_resched()) && 299 likely(!time_after(busy_clock(), endtime)) && 300 likely(!signal_pending(current)) && 301 !vhost_has_work(dev); 302 } 303 304 static int vhost_net_tx_get_vq_desc(struct vhost_net *net, 305 struct vhost_virtqueue *vq, 306 struct iovec iov[], unsigned int iov_size, 307 unsigned int *out_num, unsigned int *in_num) 308 { 309 unsigned long uninitialized_var(endtime); 310 int r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), 311 out_num, in_num, NULL, NULL); 312 313 if (r == vq->num && vq->busyloop_timeout) { 314 preempt_disable(); 315 endtime = busy_clock() + vq->busyloop_timeout; 316 while (vhost_can_busy_poll(vq->dev, endtime) && 317 vhost_vq_avail_empty(vq->dev, vq)) 318 cpu_relax_lowlatency(); 319 preempt_enable(); 320 r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), 321 out_num, in_num, NULL, NULL); 322 } 323 324 return r; 325 } 326 327 /* Expects to be always run from workqueue - which acts as 328 * read-size critical section for our kind of RCU. */ 329 static void handle_tx(struct vhost_net *net) 330 { 331 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 332 struct vhost_virtqueue *vq = &nvq->vq; 333 unsigned out, in; 334 int head; 335 struct msghdr msg = { 336 .msg_name = NULL, 337 .msg_namelen = 0, 338 .msg_control = NULL, 339 .msg_controllen = 0, 340 .msg_flags = MSG_DONTWAIT, 341 }; 342 size_t len, total_len = 0; 343 int err; 344 size_t hdr_size; 345 struct socket *sock; 346 struct vhost_net_ubuf_ref *uninitialized_var(ubufs); 347 bool zcopy, zcopy_used; 348 349 mutex_lock(&vq->mutex); 350 sock = vq->private_data; 351 if (!sock) 352 goto out; 353 354 vhost_disable_notify(&net->dev, vq); 355 356 hdr_size = nvq->vhost_hlen; 357 zcopy = nvq->ubufs; 358 359 for (;;) { 360 /* Release DMAs done buffers first */ 361 if (zcopy) 362 vhost_zerocopy_signal_used(net, vq); 363 364 /* If more outstanding DMAs, queue the work. 365 * Handle upend_idx wrap around 366 */ 367 if (unlikely((nvq->upend_idx + vq->num - VHOST_MAX_PEND) 368 % UIO_MAXIOV == nvq->done_idx)) 369 break; 370 371 head = vhost_net_tx_get_vq_desc(net, vq, vq->iov, 372 ARRAY_SIZE(vq->iov), 373 &out, &in); 374 /* On error, stop handling until the next kick. */ 375 if (unlikely(head < 0)) 376 break; 377 /* Nothing new? Wait for eventfd to tell us they refilled. */ 378 if (head == vq->num) { 379 if (unlikely(vhost_enable_notify(&net->dev, vq))) { 380 vhost_disable_notify(&net->dev, vq); 381 continue; 382 } 383 break; 384 } 385 if (in) { 386 vq_err(vq, "Unexpected descriptor format for TX: " 387 "out %d, int %d\n", out, in); 388 break; 389 } 390 /* Skip header. TODO: support TSO. */ 391 len = iov_length(vq->iov, out); 392 iov_iter_init(&msg.msg_iter, WRITE, vq->iov, out, len); 393 iov_iter_advance(&msg.msg_iter, hdr_size); 394 /* Sanity check */ 395 if (!msg_data_left(&msg)) { 396 vq_err(vq, "Unexpected header len for TX: " 397 "%zd expected %zd\n", 398 len, hdr_size); 399 break; 400 } 401 len = msg_data_left(&msg); 402 403 zcopy_used = zcopy && len >= VHOST_GOODCOPY_LEN 404 && (nvq->upend_idx + 1) % UIO_MAXIOV != 405 nvq->done_idx 406 && vhost_net_tx_select_zcopy(net); 407 408 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 409 if (zcopy_used) { 410 struct ubuf_info *ubuf; 411 ubuf = nvq->ubuf_info + nvq->upend_idx; 412 413 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); 414 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; 415 ubuf->callback = vhost_zerocopy_callback; 416 ubuf->ctx = nvq->ubufs; 417 ubuf->desc = nvq->upend_idx; 418 msg.msg_control = ubuf; 419 msg.msg_controllen = sizeof(ubuf); 420 ubufs = nvq->ubufs; 421 atomic_inc(&ubufs->refcount); 422 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; 423 } else { 424 msg.msg_control = NULL; 425 ubufs = NULL; 426 } 427 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 428 err = sock->ops->sendmsg(sock, &msg, len); 429 if (unlikely(err < 0)) { 430 if (zcopy_used) { 431 vhost_net_ubuf_put(ubufs); 432 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) 433 % UIO_MAXIOV; 434 } 435 vhost_discard_vq_desc(vq, 1); 436 break; 437 } 438 if (err != len) 439 pr_debug("Truncated TX packet: " 440 " len %d != %zd\n", err, len); 441 if (!zcopy_used) 442 vhost_add_used_and_signal(&net->dev, vq, head, 0); 443 else 444 vhost_zerocopy_signal_used(net, vq); 445 total_len += len; 446 vhost_net_tx_packet(net); 447 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 448 vhost_poll_queue(&vq->poll); 449 break; 450 } 451 } 452 out: 453 mutex_unlock(&vq->mutex); 454 } 455 456 static int peek_head_len(struct sock *sk) 457 { 458 struct sk_buff *head; 459 int len = 0; 460 unsigned long flags; 461 462 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); 463 head = skb_peek(&sk->sk_receive_queue); 464 if (likely(head)) { 465 len = head->len; 466 if (skb_vlan_tag_present(head)) 467 len += VLAN_HLEN; 468 } 469 470 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); 471 return len; 472 } 473 474 static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk) 475 { 476 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 477 struct vhost_virtqueue *vq = &nvq->vq; 478 unsigned long uninitialized_var(endtime); 479 int len = peek_head_len(sk); 480 481 if (!len && vq->busyloop_timeout) { 482 /* Both tx vq and rx socket were polled here */ 483 mutex_lock(&vq->mutex); 484 vhost_disable_notify(&net->dev, vq); 485 486 preempt_disable(); 487 endtime = busy_clock() + vq->busyloop_timeout; 488 489 while (vhost_can_busy_poll(&net->dev, endtime) && 490 skb_queue_empty(&sk->sk_receive_queue) && 491 vhost_vq_avail_empty(&net->dev, vq)) 492 cpu_relax_lowlatency(); 493 494 preempt_enable(); 495 496 if (vhost_enable_notify(&net->dev, vq)) 497 vhost_poll_queue(&vq->poll); 498 mutex_unlock(&vq->mutex); 499 500 len = peek_head_len(sk); 501 } 502 503 return len; 504 } 505 506 /* This is a multi-buffer version of vhost_get_desc, that works if 507 * vq has read descriptors only. 508 * @vq - the relevant virtqueue 509 * @datalen - data length we'll be reading 510 * @iovcount - returned count of io vectors we fill 511 * @log - vhost log 512 * @log_num - log offset 513 * @quota - headcount quota, 1 for big buffer 514 * returns number of buffer heads allocated, negative on error 515 */ 516 static int get_rx_bufs(struct vhost_virtqueue *vq, 517 struct vring_used_elem *heads, 518 int datalen, 519 unsigned *iovcount, 520 struct vhost_log *log, 521 unsigned *log_num, 522 unsigned int quota) 523 { 524 unsigned int out, in; 525 int seg = 0; 526 int headcount = 0; 527 unsigned d; 528 int r, nlogs = 0; 529 /* len is always initialized before use since we are always called with 530 * datalen > 0. 531 */ 532 u32 uninitialized_var(len); 533 534 while (datalen > 0 && headcount < quota) { 535 if (unlikely(seg >= UIO_MAXIOV)) { 536 r = -ENOBUFS; 537 goto err; 538 } 539 r = vhost_get_vq_desc(vq, vq->iov + seg, 540 ARRAY_SIZE(vq->iov) - seg, &out, 541 &in, log, log_num); 542 if (unlikely(r < 0)) 543 goto err; 544 545 d = r; 546 if (d == vq->num) { 547 r = 0; 548 goto err; 549 } 550 if (unlikely(out || in <= 0)) { 551 vq_err(vq, "unexpected descriptor format for RX: " 552 "out %d, in %d\n", out, in); 553 r = -EINVAL; 554 goto err; 555 } 556 if (unlikely(log)) { 557 nlogs += *log_num; 558 log += *log_num; 559 } 560 heads[headcount].id = cpu_to_vhost32(vq, d); 561 len = iov_length(vq->iov + seg, in); 562 heads[headcount].len = cpu_to_vhost32(vq, len); 563 datalen -= len; 564 ++headcount; 565 seg += in; 566 } 567 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); 568 *iovcount = seg; 569 if (unlikely(log)) 570 *log_num = nlogs; 571 572 /* Detect overrun */ 573 if (unlikely(datalen > 0)) { 574 r = UIO_MAXIOV + 1; 575 goto err; 576 } 577 return headcount; 578 err: 579 vhost_discard_vq_desc(vq, headcount); 580 return r; 581 } 582 583 /* Expects to be always run from workqueue - which acts as 584 * read-size critical section for our kind of RCU. */ 585 static void handle_rx(struct vhost_net *net) 586 { 587 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; 588 struct vhost_virtqueue *vq = &nvq->vq; 589 unsigned uninitialized_var(in), log; 590 struct vhost_log *vq_log; 591 struct msghdr msg = { 592 .msg_name = NULL, 593 .msg_namelen = 0, 594 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 595 .msg_controllen = 0, 596 .msg_flags = MSG_DONTWAIT, 597 }; 598 struct virtio_net_hdr hdr = { 599 .flags = 0, 600 .gso_type = VIRTIO_NET_HDR_GSO_NONE 601 }; 602 size_t total_len = 0; 603 int err, mergeable; 604 s16 headcount; 605 size_t vhost_hlen, sock_hlen; 606 size_t vhost_len, sock_len; 607 struct socket *sock; 608 struct iov_iter fixup; 609 __virtio16 num_buffers; 610 611 mutex_lock(&vq->mutex); 612 sock = vq->private_data; 613 if (!sock) 614 goto out; 615 vhost_disable_notify(&net->dev, vq); 616 617 vhost_hlen = nvq->vhost_hlen; 618 sock_hlen = nvq->sock_hlen; 619 620 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ? 621 vq->log : NULL; 622 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); 623 624 while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk))) { 625 sock_len += sock_hlen; 626 vhost_len = sock_len + vhost_hlen; 627 headcount = get_rx_bufs(vq, vq->heads, vhost_len, 628 &in, vq_log, &log, 629 likely(mergeable) ? UIO_MAXIOV : 1); 630 /* On error, stop handling until the next kick. */ 631 if (unlikely(headcount < 0)) 632 break; 633 /* On overrun, truncate and discard */ 634 if (unlikely(headcount > UIO_MAXIOV)) { 635 iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1); 636 err = sock->ops->recvmsg(sock, &msg, 637 1, MSG_DONTWAIT | MSG_TRUNC); 638 pr_debug("Discarded rx packet: len %zd\n", sock_len); 639 continue; 640 } 641 /* OK, now we need to know about added descriptors. */ 642 if (!headcount) { 643 if (unlikely(vhost_enable_notify(&net->dev, vq))) { 644 /* They have slipped one in as we were 645 * doing that: check again. */ 646 vhost_disable_notify(&net->dev, vq); 647 continue; 648 } 649 /* Nothing new? Wait for eventfd to tell us 650 * they refilled. */ 651 break; 652 } 653 /* We don't need to be notified again. */ 654 iov_iter_init(&msg.msg_iter, READ, vq->iov, in, vhost_len); 655 fixup = msg.msg_iter; 656 if (unlikely((vhost_hlen))) { 657 /* We will supply the header ourselves 658 * TODO: support TSO. 659 */ 660 iov_iter_advance(&msg.msg_iter, vhost_hlen); 661 } 662 err = sock->ops->recvmsg(sock, &msg, 663 sock_len, MSG_DONTWAIT | MSG_TRUNC); 664 /* Userspace might have consumed the packet meanwhile: 665 * it's not supposed to do this usually, but might be hard 666 * to prevent. Discard data we got (if any) and keep going. */ 667 if (unlikely(err != sock_len)) { 668 pr_debug("Discarded rx packet: " 669 " len %d, expected %zd\n", err, sock_len); 670 vhost_discard_vq_desc(vq, headcount); 671 continue; 672 } 673 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ 674 if (unlikely(vhost_hlen)) { 675 if (copy_to_iter(&hdr, sizeof(hdr), 676 &fixup) != sizeof(hdr)) { 677 vq_err(vq, "Unable to write vnet_hdr " 678 "at addr %p\n", vq->iov->iov_base); 679 break; 680 } 681 } else { 682 /* Header came from socket; we'll need to patch 683 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF 684 */ 685 iov_iter_advance(&fixup, sizeof(hdr)); 686 } 687 /* TODO: Should check and handle checksum. */ 688 689 num_buffers = cpu_to_vhost16(vq, headcount); 690 if (likely(mergeable) && 691 copy_to_iter(&num_buffers, sizeof num_buffers, 692 &fixup) != sizeof num_buffers) { 693 vq_err(vq, "Failed num_buffers write"); 694 vhost_discard_vq_desc(vq, headcount); 695 break; 696 } 697 vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, 698 headcount); 699 if (unlikely(vq_log)) 700 vhost_log_write(vq, vq_log, log, vhost_len); 701 total_len += vhost_len; 702 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 703 vhost_poll_queue(&vq->poll); 704 break; 705 } 706 } 707 out: 708 mutex_unlock(&vq->mutex); 709 } 710 711 static void handle_tx_kick(struct vhost_work *work) 712 { 713 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 714 poll.work); 715 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 716 717 handle_tx(net); 718 } 719 720 static void handle_rx_kick(struct vhost_work *work) 721 { 722 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 723 poll.work); 724 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 725 726 handle_rx(net); 727 } 728 729 static void handle_tx_net(struct vhost_work *work) 730 { 731 struct vhost_net *net = container_of(work, struct vhost_net, 732 poll[VHOST_NET_VQ_TX].work); 733 handle_tx(net); 734 } 735 736 static void handle_rx_net(struct vhost_work *work) 737 { 738 struct vhost_net *net = container_of(work, struct vhost_net, 739 poll[VHOST_NET_VQ_RX].work); 740 handle_rx(net); 741 } 742 743 static int vhost_net_open(struct inode *inode, struct file *f) 744 { 745 struct vhost_net *n; 746 struct vhost_dev *dev; 747 struct vhost_virtqueue **vqs; 748 int i; 749 750 n = kmalloc(sizeof *n, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT); 751 if (!n) { 752 n = vmalloc(sizeof *n); 753 if (!n) 754 return -ENOMEM; 755 } 756 vqs = kmalloc(VHOST_NET_VQ_MAX * sizeof(*vqs), GFP_KERNEL); 757 if (!vqs) { 758 kvfree(n); 759 return -ENOMEM; 760 } 761 762 dev = &n->dev; 763 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; 764 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; 765 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; 766 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; 767 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 768 n->vqs[i].ubufs = NULL; 769 n->vqs[i].ubuf_info = NULL; 770 n->vqs[i].upend_idx = 0; 771 n->vqs[i].done_idx = 0; 772 n->vqs[i].vhost_hlen = 0; 773 n->vqs[i].sock_hlen = 0; 774 } 775 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX); 776 777 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev); 778 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev); 779 780 f->private_data = n; 781 782 return 0; 783 } 784 785 static void vhost_net_disable_vq(struct vhost_net *n, 786 struct vhost_virtqueue *vq) 787 { 788 struct vhost_net_virtqueue *nvq = 789 container_of(vq, struct vhost_net_virtqueue, vq); 790 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 791 if (!vq->private_data) 792 return; 793 vhost_poll_stop(poll); 794 } 795 796 static int vhost_net_enable_vq(struct vhost_net *n, 797 struct vhost_virtqueue *vq) 798 { 799 struct vhost_net_virtqueue *nvq = 800 container_of(vq, struct vhost_net_virtqueue, vq); 801 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 802 struct socket *sock; 803 804 sock = vq->private_data; 805 if (!sock) 806 return 0; 807 808 return vhost_poll_start(poll, sock->file); 809 } 810 811 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 812 struct vhost_virtqueue *vq) 813 { 814 struct socket *sock; 815 816 mutex_lock(&vq->mutex); 817 sock = vq->private_data; 818 vhost_net_disable_vq(n, vq); 819 vq->private_data = NULL; 820 mutex_unlock(&vq->mutex); 821 return sock; 822 } 823 824 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 825 struct socket **rx_sock) 826 { 827 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); 828 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); 829 } 830 831 static void vhost_net_flush_vq(struct vhost_net *n, int index) 832 { 833 vhost_poll_flush(n->poll + index); 834 vhost_poll_flush(&n->vqs[index].vq.poll); 835 } 836 837 static void vhost_net_flush(struct vhost_net *n) 838 { 839 vhost_net_flush_vq(n, VHOST_NET_VQ_TX); 840 vhost_net_flush_vq(n, VHOST_NET_VQ_RX); 841 if (n->vqs[VHOST_NET_VQ_TX].ubufs) { 842 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 843 n->tx_flush = true; 844 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 845 /* Wait for all lower device DMAs done. */ 846 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); 847 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 848 n->tx_flush = false; 849 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); 850 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 851 } 852 } 853 854 static int vhost_net_release(struct inode *inode, struct file *f) 855 { 856 struct vhost_net *n = f->private_data; 857 struct socket *tx_sock; 858 struct socket *rx_sock; 859 860 vhost_net_stop(n, &tx_sock, &rx_sock); 861 vhost_net_flush(n); 862 vhost_dev_stop(&n->dev); 863 vhost_dev_cleanup(&n->dev, false); 864 vhost_net_vq_reset(n); 865 if (tx_sock) 866 sockfd_put(tx_sock); 867 if (rx_sock) 868 sockfd_put(rx_sock); 869 /* Make sure no callbacks are outstanding */ 870 synchronize_rcu_bh(); 871 /* We do an extra flush before freeing memory, 872 * since jobs can re-queue themselves. */ 873 vhost_net_flush(n); 874 kfree(n->dev.vqs); 875 kvfree(n); 876 return 0; 877 } 878 879 static struct socket *get_raw_socket(int fd) 880 { 881 struct { 882 struct sockaddr_ll sa; 883 char buf[MAX_ADDR_LEN]; 884 } uaddr; 885 int uaddr_len = sizeof uaddr, r; 886 struct socket *sock = sockfd_lookup(fd, &r); 887 888 if (!sock) 889 return ERR_PTR(-ENOTSOCK); 890 891 /* Parameter checking */ 892 if (sock->sk->sk_type != SOCK_RAW) { 893 r = -ESOCKTNOSUPPORT; 894 goto err; 895 } 896 897 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 898 &uaddr_len, 0); 899 if (r) 900 goto err; 901 902 if (uaddr.sa.sll_family != AF_PACKET) { 903 r = -EPFNOSUPPORT; 904 goto err; 905 } 906 return sock; 907 err: 908 sockfd_put(sock); 909 return ERR_PTR(r); 910 } 911 912 static struct socket *get_tap_socket(int fd) 913 { 914 struct file *file = fget(fd); 915 struct socket *sock; 916 917 if (!file) 918 return ERR_PTR(-EBADF); 919 sock = tun_get_socket(file); 920 if (!IS_ERR(sock)) 921 return sock; 922 sock = macvtap_get_socket(file); 923 if (IS_ERR(sock)) 924 fput(file); 925 return sock; 926 } 927 928 static struct socket *get_socket(int fd) 929 { 930 struct socket *sock; 931 932 /* special case to disable backend */ 933 if (fd == -1) 934 return NULL; 935 sock = get_raw_socket(fd); 936 if (!IS_ERR(sock)) 937 return sock; 938 sock = get_tap_socket(fd); 939 if (!IS_ERR(sock)) 940 return sock; 941 return ERR_PTR(-ENOTSOCK); 942 } 943 944 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 945 { 946 struct socket *sock, *oldsock; 947 struct vhost_virtqueue *vq; 948 struct vhost_net_virtqueue *nvq; 949 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; 950 int r; 951 952 mutex_lock(&n->dev.mutex); 953 r = vhost_dev_check_owner(&n->dev); 954 if (r) 955 goto err; 956 957 if (index >= VHOST_NET_VQ_MAX) { 958 r = -ENOBUFS; 959 goto err; 960 } 961 vq = &n->vqs[index].vq; 962 nvq = &n->vqs[index]; 963 mutex_lock(&vq->mutex); 964 965 /* Verify that ring has been setup correctly. */ 966 if (!vhost_vq_access_ok(vq)) { 967 r = -EFAULT; 968 goto err_vq; 969 } 970 sock = get_socket(fd); 971 if (IS_ERR(sock)) { 972 r = PTR_ERR(sock); 973 goto err_vq; 974 } 975 976 /* start polling new socket */ 977 oldsock = vq->private_data; 978 if (sock != oldsock) { 979 ubufs = vhost_net_ubuf_alloc(vq, 980 sock && vhost_sock_zcopy(sock)); 981 if (IS_ERR(ubufs)) { 982 r = PTR_ERR(ubufs); 983 goto err_ubufs; 984 } 985 986 vhost_net_disable_vq(n, vq); 987 vq->private_data = sock; 988 r = vhost_vq_init_access(vq); 989 if (r) 990 goto err_used; 991 r = vhost_net_enable_vq(n, vq); 992 if (r) 993 goto err_used; 994 995 oldubufs = nvq->ubufs; 996 nvq->ubufs = ubufs; 997 998 n->tx_packets = 0; 999 n->tx_zcopy_err = 0; 1000 n->tx_flush = false; 1001 } 1002 1003 mutex_unlock(&vq->mutex); 1004 1005 if (oldubufs) { 1006 vhost_net_ubuf_put_wait_and_free(oldubufs); 1007 mutex_lock(&vq->mutex); 1008 vhost_zerocopy_signal_used(n, vq); 1009 mutex_unlock(&vq->mutex); 1010 } 1011 1012 if (oldsock) { 1013 vhost_net_flush_vq(n, index); 1014 sockfd_put(oldsock); 1015 } 1016 1017 mutex_unlock(&n->dev.mutex); 1018 return 0; 1019 1020 err_used: 1021 vq->private_data = oldsock; 1022 vhost_net_enable_vq(n, vq); 1023 if (ubufs) 1024 vhost_net_ubuf_put_wait_and_free(ubufs); 1025 err_ubufs: 1026 sockfd_put(sock); 1027 err_vq: 1028 mutex_unlock(&vq->mutex); 1029 err: 1030 mutex_unlock(&n->dev.mutex); 1031 return r; 1032 } 1033 1034 static long vhost_net_reset_owner(struct vhost_net *n) 1035 { 1036 struct socket *tx_sock = NULL; 1037 struct socket *rx_sock = NULL; 1038 long err; 1039 struct vhost_memory *memory; 1040 1041 mutex_lock(&n->dev.mutex); 1042 err = vhost_dev_check_owner(&n->dev); 1043 if (err) 1044 goto done; 1045 memory = vhost_dev_reset_owner_prepare(); 1046 if (!memory) { 1047 err = -ENOMEM; 1048 goto done; 1049 } 1050 vhost_net_stop(n, &tx_sock, &rx_sock); 1051 vhost_net_flush(n); 1052 vhost_dev_reset_owner(&n->dev, memory); 1053 vhost_net_vq_reset(n); 1054 done: 1055 mutex_unlock(&n->dev.mutex); 1056 if (tx_sock) 1057 sockfd_put(tx_sock); 1058 if (rx_sock) 1059 sockfd_put(rx_sock); 1060 return err; 1061 } 1062 1063 static int vhost_net_set_features(struct vhost_net *n, u64 features) 1064 { 1065 size_t vhost_hlen, sock_hlen, hdr_len; 1066 int i; 1067 1068 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | 1069 (1ULL << VIRTIO_F_VERSION_1))) ? 1070 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 1071 sizeof(struct virtio_net_hdr); 1072 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 1073 /* vhost provides vnet_hdr */ 1074 vhost_hlen = hdr_len; 1075 sock_hlen = 0; 1076 } else { 1077 /* socket provides vnet_hdr */ 1078 vhost_hlen = 0; 1079 sock_hlen = hdr_len; 1080 } 1081 mutex_lock(&n->dev.mutex); 1082 if ((features & (1 << VHOST_F_LOG_ALL)) && 1083 !vhost_log_access_ok(&n->dev)) { 1084 mutex_unlock(&n->dev.mutex); 1085 return -EFAULT; 1086 } 1087 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1088 mutex_lock(&n->vqs[i].vq.mutex); 1089 n->vqs[i].vq.acked_features = features; 1090 n->vqs[i].vhost_hlen = vhost_hlen; 1091 n->vqs[i].sock_hlen = sock_hlen; 1092 mutex_unlock(&n->vqs[i].vq.mutex); 1093 } 1094 mutex_unlock(&n->dev.mutex); 1095 return 0; 1096 } 1097 1098 static long vhost_net_set_owner(struct vhost_net *n) 1099 { 1100 int r; 1101 1102 mutex_lock(&n->dev.mutex); 1103 if (vhost_dev_has_owner(&n->dev)) { 1104 r = -EBUSY; 1105 goto out; 1106 } 1107 r = vhost_net_set_ubuf_info(n); 1108 if (r) 1109 goto out; 1110 r = vhost_dev_set_owner(&n->dev); 1111 if (r) 1112 vhost_net_clear_ubuf_info(n); 1113 vhost_net_flush(n); 1114 out: 1115 mutex_unlock(&n->dev.mutex); 1116 return r; 1117 } 1118 1119 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 1120 unsigned long arg) 1121 { 1122 struct vhost_net *n = f->private_data; 1123 void __user *argp = (void __user *)arg; 1124 u64 __user *featurep = argp; 1125 struct vhost_vring_file backend; 1126 u64 features; 1127 int r; 1128 1129 switch (ioctl) { 1130 case VHOST_NET_SET_BACKEND: 1131 if (copy_from_user(&backend, argp, sizeof backend)) 1132 return -EFAULT; 1133 return vhost_net_set_backend(n, backend.index, backend.fd); 1134 case VHOST_GET_FEATURES: 1135 features = VHOST_NET_FEATURES; 1136 if (copy_to_user(featurep, &features, sizeof features)) 1137 return -EFAULT; 1138 return 0; 1139 case VHOST_SET_FEATURES: 1140 if (copy_from_user(&features, featurep, sizeof features)) 1141 return -EFAULT; 1142 if (features & ~VHOST_NET_FEATURES) 1143 return -EOPNOTSUPP; 1144 return vhost_net_set_features(n, features); 1145 case VHOST_RESET_OWNER: 1146 return vhost_net_reset_owner(n); 1147 case VHOST_SET_OWNER: 1148 return vhost_net_set_owner(n); 1149 default: 1150 mutex_lock(&n->dev.mutex); 1151 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 1152 if (r == -ENOIOCTLCMD) 1153 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 1154 else 1155 vhost_net_flush(n); 1156 mutex_unlock(&n->dev.mutex); 1157 return r; 1158 } 1159 } 1160 1161 #ifdef CONFIG_COMPAT 1162 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, 1163 unsigned long arg) 1164 { 1165 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); 1166 } 1167 #endif 1168 1169 static const struct file_operations vhost_net_fops = { 1170 .owner = THIS_MODULE, 1171 .release = vhost_net_release, 1172 .unlocked_ioctl = vhost_net_ioctl, 1173 #ifdef CONFIG_COMPAT 1174 .compat_ioctl = vhost_net_compat_ioctl, 1175 #endif 1176 .open = vhost_net_open, 1177 .llseek = noop_llseek, 1178 }; 1179 1180 static struct miscdevice vhost_net_misc = { 1181 .minor = VHOST_NET_MINOR, 1182 .name = "vhost-net", 1183 .fops = &vhost_net_fops, 1184 }; 1185 1186 static int vhost_net_init(void) 1187 { 1188 if (experimental_zcopytx) 1189 vhost_net_enable_zcopy(VHOST_NET_VQ_TX); 1190 return misc_register(&vhost_net_misc); 1191 } 1192 module_init(vhost_net_init); 1193 1194 static void vhost_net_exit(void) 1195 { 1196 misc_deregister(&vhost_net_misc); 1197 } 1198 module_exit(vhost_net_exit); 1199 1200 MODULE_VERSION("0.0.1"); 1201 MODULE_LICENSE("GPL v2"); 1202 MODULE_AUTHOR("Michael S. Tsirkin"); 1203 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1204 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1205 MODULE_ALIAS("devname:vhost-net"); 1206