1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (C) 2009 Red Hat, Inc. 3 * Author: Michael S. Tsirkin <mst@redhat.com> 4 * 5 * virtio-net server in host kernel. 6 */ 7 8 #include <linux/compat.h> 9 #include <linux/eventfd.h> 10 #include <linux/vhost.h> 11 #include <linux/virtio_net.h> 12 #include <linux/miscdevice.h> 13 #include <linux/module.h> 14 #include <linux/moduleparam.h> 15 #include <linux/mutex.h> 16 #include <linux/workqueue.h> 17 #include <linux/file.h> 18 #include <linux/slab.h> 19 #include <linux/sched/clock.h> 20 #include <linux/sched/signal.h> 21 #include <linux/vmalloc.h> 22 23 #include <linux/net.h> 24 #include <linux/if_packet.h> 25 #include <linux/if_arp.h> 26 #include <linux/if_tun.h> 27 #include <linux/if_macvlan.h> 28 #include <linux/if_tap.h> 29 #include <linux/if_vlan.h> 30 #include <linux/skb_array.h> 31 #include <linux/skbuff.h> 32 33 #include <net/sock.h> 34 #include <net/xdp.h> 35 36 #include "vhost.h" 37 38 static int experimental_zcopytx = 0; 39 module_param(experimental_zcopytx, int, 0444); 40 MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" 41 " 1 -Enable; 0 - Disable"); 42 43 /* Max number of bytes transferred before requeueing the job. 44 * Using this limit prevents one virtqueue from starving others. */ 45 #define VHOST_NET_WEIGHT 0x80000 46 47 /* Max number of packets transferred before requeueing the job. 48 * Using this limit prevents one virtqueue from starving others with small 49 * pkts. 50 */ 51 #define VHOST_NET_PKT_WEIGHT 256 52 53 /* MAX number of TX used buffers for outstanding zerocopy */ 54 #define VHOST_MAX_PEND 128 55 #define VHOST_GOODCOPY_LEN 256 56 57 /* 58 * For transmit, used buffer len is unused; we override it to track buffer 59 * status internally; used for zerocopy tx only. 60 */ 61 /* Lower device DMA failed */ 62 #define VHOST_DMA_FAILED_LEN ((__force __virtio32)3) 63 /* Lower device DMA done */ 64 #define VHOST_DMA_DONE_LEN ((__force __virtio32)2) 65 /* Lower device DMA in progress */ 66 #define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) 67 /* Buffer unused */ 68 #define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) 69 70 #define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) 71 72 enum { 73 VHOST_NET_FEATURES = VHOST_FEATURES | 74 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | 75 (1ULL << VIRTIO_NET_F_MRG_RXBUF) | 76 (1ULL << VIRTIO_F_ACCESS_PLATFORM) | 77 (1ULL << VIRTIO_F_RING_RESET) 78 }; 79 80 enum { 81 VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) 82 }; 83 84 enum { 85 VHOST_NET_VQ_RX = 0, 86 VHOST_NET_VQ_TX = 1, 87 VHOST_NET_VQ_MAX = 2, 88 }; 89 90 struct vhost_net_ubuf_ref { 91 /* refcount follows semantics similar to kref: 92 * 0: object is released 93 * 1: no outstanding ubufs 94 * >1: outstanding ubufs 95 */ 96 atomic_t refcount; 97 wait_queue_head_t wait; 98 struct vhost_virtqueue *vq; 99 }; 100 101 #define VHOST_NET_BATCH 64 102 struct vhost_net_buf { 103 void **queue; 104 int tail; 105 int head; 106 }; 107 108 struct vhost_net_virtqueue { 109 struct vhost_virtqueue vq; 110 size_t vhost_hlen; 111 size_t sock_hlen; 112 /* vhost zerocopy support fields below: */ 113 /* last used idx for outstanding DMA zerocopy buffers */ 114 int upend_idx; 115 /* For TX, first used idx for DMA done zerocopy buffers 116 * For RX, number of batched heads 117 */ 118 int done_idx; 119 /* Number of XDP frames batched */ 120 int batched_xdp; 121 /* an array of userspace buffers info */ 122 struct ubuf_info_msgzc *ubuf_info; 123 /* Reference counting for outstanding ubufs. 124 * Protected by vq mutex. Writers must also take device mutex. */ 125 struct vhost_net_ubuf_ref *ubufs; 126 struct ptr_ring *rx_ring; 127 struct vhost_net_buf rxq; 128 /* Batched XDP buffs */ 129 struct xdp_buff *xdp; 130 }; 131 132 struct vhost_net { 133 struct vhost_dev dev; 134 struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX]; 135 struct vhost_poll poll[VHOST_NET_VQ_MAX]; 136 /* Number of TX recently submitted. 137 * Protected by tx vq lock. */ 138 unsigned tx_packets; 139 /* Number of times zerocopy TX recently failed. 140 * Protected by tx vq lock. */ 141 unsigned tx_zcopy_err; 142 /* Flush in progress. Protected by tx vq lock. */ 143 bool tx_flush; 144 /* Private page frag cache */ 145 struct page_frag_cache pf_cache; 146 }; 147 148 static unsigned vhost_net_zcopy_mask __read_mostly; 149 150 static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq) 151 { 152 if (rxq->tail != rxq->head) 153 return rxq->queue[rxq->head]; 154 else 155 return NULL; 156 } 157 158 static int vhost_net_buf_get_size(struct vhost_net_buf *rxq) 159 { 160 return rxq->tail - rxq->head; 161 } 162 163 static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq) 164 { 165 return rxq->tail == rxq->head; 166 } 167 168 static void *vhost_net_buf_consume(struct vhost_net_buf *rxq) 169 { 170 void *ret = vhost_net_buf_get_ptr(rxq); 171 ++rxq->head; 172 return ret; 173 } 174 175 static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq) 176 { 177 struct vhost_net_buf *rxq = &nvq->rxq; 178 179 rxq->head = 0; 180 rxq->tail = ptr_ring_consume_batched(nvq->rx_ring, rxq->queue, 181 VHOST_NET_BATCH); 182 return rxq->tail; 183 } 184 185 static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq) 186 { 187 struct vhost_net_buf *rxq = &nvq->rxq; 188 189 if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) { 190 ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head, 191 vhost_net_buf_get_size(rxq), 192 tun_ptr_free); 193 rxq->head = rxq->tail = 0; 194 } 195 } 196 197 static int vhost_net_buf_peek_len(void *ptr) 198 { 199 if (tun_is_xdp_frame(ptr)) { 200 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr); 201 202 return xdpf->len; 203 } 204 205 return __skb_array_len_with_tag(ptr); 206 } 207 208 static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq) 209 { 210 struct vhost_net_buf *rxq = &nvq->rxq; 211 212 if (!vhost_net_buf_is_empty(rxq)) 213 goto out; 214 215 if (!vhost_net_buf_produce(nvq)) 216 return 0; 217 218 out: 219 return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq)); 220 } 221 222 static void vhost_net_buf_init(struct vhost_net_buf *rxq) 223 { 224 rxq->head = rxq->tail = 0; 225 } 226 227 static void vhost_net_enable_zcopy(int vq) 228 { 229 vhost_net_zcopy_mask |= 0x1 << vq; 230 } 231 232 static struct vhost_net_ubuf_ref * 233 vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy) 234 { 235 struct vhost_net_ubuf_ref *ubufs; 236 /* No zero copy backend? Nothing to count. */ 237 if (!zcopy) 238 return NULL; 239 ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL); 240 if (!ubufs) 241 return ERR_PTR(-ENOMEM); 242 atomic_set(&ubufs->refcount, 1); 243 init_waitqueue_head(&ubufs->wait); 244 ubufs->vq = vq; 245 return ubufs; 246 } 247 248 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs) 249 { 250 int r = atomic_sub_return(1, &ubufs->refcount); 251 if (unlikely(!r)) 252 wake_up(&ubufs->wait); 253 return r; 254 } 255 256 static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) 257 { 258 vhost_net_ubuf_put(ubufs); 259 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); 260 } 261 262 static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) 263 { 264 vhost_net_ubuf_put_and_wait(ubufs); 265 kfree(ubufs); 266 } 267 268 static void vhost_net_clear_ubuf_info(struct vhost_net *n) 269 { 270 int i; 271 272 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 273 kfree(n->vqs[i].ubuf_info); 274 n->vqs[i].ubuf_info = NULL; 275 } 276 } 277 278 static int vhost_net_set_ubuf_info(struct vhost_net *n) 279 { 280 bool zcopy; 281 int i; 282 283 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 284 zcopy = vhost_net_zcopy_mask & (0x1 << i); 285 if (!zcopy) 286 continue; 287 n->vqs[i].ubuf_info = 288 kmalloc_array(UIO_MAXIOV, 289 sizeof(*n->vqs[i].ubuf_info), 290 GFP_KERNEL); 291 if (!n->vqs[i].ubuf_info) 292 goto err; 293 } 294 return 0; 295 296 err: 297 vhost_net_clear_ubuf_info(n); 298 return -ENOMEM; 299 } 300 301 static void vhost_net_vq_reset(struct vhost_net *n) 302 { 303 int i; 304 305 vhost_net_clear_ubuf_info(n); 306 307 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 308 n->vqs[i].done_idx = 0; 309 n->vqs[i].upend_idx = 0; 310 n->vqs[i].ubufs = NULL; 311 n->vqs[i].vhost_hlen = 0; 312 n->vqs[i].sock_hlen = 0; 313 vhost_net_buf_init(&n->vqs[i].rxq); 314 } 315 316 } 317 318 static void vhost_net_tx_packet(struct vhost_net *net) 319 { 320 ++net->tx_packets; 321 if (net->tx_packets < 1024) 322 return; 323 net->tx_packets = 0; 324 net->tx_zcopy_err = 0; 325 } 326 327 static void vhost_net_tx_err(struct vhost_net *net) 328 { 329 ++net->tx_zcopy_err; 330 } 331 332 static bool vhost_net_tx_select_zcopy(struct vhost_net *net) 333 { 334 /* TX flush waits for outstanding DMAs to be done. 335 * Don't start new DMAs. 336 */ 337 return !net->tx_flush && 338 net->tx_packets / 64 >= net->tx_zcopy_err; 339 } 340 341 static bool vhost_sock_zcopy(struct socket *sock) 342 { 343 return unlikely(experimental_zcopytx) && 344 sock_flag(sock->sk, SOCK_ZEROCOPY); 345 } 346 347 static bool vhost_sock_xdp(struct socket *sock) 348 { 349 return sock_flag(sock->sk, SOCK_XDP); 350 } 351 352 /* In case of DMA done not in order in lower device driver for some reason. 353 * upend_idx is used to track end of used idx, done_idx is used to track head 354 * of used idx. Once lower device DMA done contiguously, we will signal KVM 355 * guest used idx. 356 */ 357 static void vhost_zerocopy_signal_used(struct vhost_net *net, 358 struct vhost_virtqueue *vq) 359 { 360 struct vhost_net_virtqueue *nvq = 361 container_of(vq, struct vhost_net_virtqueue, vq); 362 int i, add; 363 int j = 0; 364 365 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { 366 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) 367 vhost_net_tx_err(net); 368 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { 369 vq->heads[i].len = VHOST_DMA_CLEAR_LEN; 370 ++j; 371 } else 372 break; 373 } 374 while (j) { 375 add = min(UIO_MAXIOV - nvq->done_idx, j); 376 vhost_add_used_and_signal_n(vq->dev, vq, 377 &vq->heads[nvq->done_idx], add); 378 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; 379 j -= add; 380 } 381 } 382 383 static void vhost_zerocopy_complete(struct sk_buff *skb, 384 struct ubuf_info *ubuf_base, bool success) 385 { 386 struct ubuf_info_msgzc *ubuf = uarg_to_msgzc(ubuf_base); 387 struct vhost_net_ubuf_ref *ubufs = ubuf->ctx; 388 struct vhost_virtqueue *vq = ubufs->vq; 389 int cnt; 390 391 rcu_read_lock_bh(); 392 393 /* set len to mark this desc buffers done DMA */ 394 vq->heads[ubuf->desc].len = success ? 395 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; 396 cnt = vhost_net_ubuf_put(ubufs); 397 398 /* 399 * Trigger polling thread if guest stopped submitting new buffers: 400 * in this case, the refcount after decrement will eventually reach 1. 401 * We also trigger polling periodically after each 16 packets 402 * (the value 16 here is more or less arbitrary, it's tuned to trigger 403 * less than 10% of times). 404 */ 405 if (cnt <= 1 || !(cnt % 16)) 406 vhost_poll_queue(&vq->poll); 407 408 rcu_read_unlock_bh(); 409 } 410 411 static const struct ubuf_info_ops vhost_ubuf_ops = { 412 .complete = vhost_zerocopy_complete, 413 }; 414 415 static inline unsigned long busy_clock(void) 416 { 417 return local_clock() >> 10; 418 } 419 420 static bool vhost_can_busy_poll(unsigned long endtime) 421 { 422 return likely(!need_resched() && !time_after(busy_clock(), endtime) && 423 !signal_pending(current)); 424 } 425 426 static void vhost_net_disable_vq(struct vhost_net *n, 427 struct vhost_virtqueue *vq) 428 { 429 struct vhost_net_virtqueue *nvq = 430 container_of(vq, struct vhost_net_virtqueue, vq); 431 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 432 if (!vhost_vq_get_backend(vq)) 433 return; 434 vhost_poll_stop(poll); 435 } 436 437 static int vhost_net_enable_vq(struct vhost_net *n, 438 struct vhost_virtqueue *vq) 439 { 440 struct vhost_net_virtqueue *nvq = 441 container_of(vq, struct vhost_net_virtqueue, vq); 442 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 443 struct socket *sock; 444 445 sock = vhost_vq_get_backend(vq); 446 if (!sock) 447 return 0; 448 449 return vhost_poll_start(poll, sock->file); 450 } 451 452 static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq) 453 { 454 struct vhost_virtqueue *vq = &nvq->vq; 455 struct vhost_dev *dev = vq->dev; 456 457 if (!nvq->done_idx) 458 return; 459 460 vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx); 461 nvq->done_idx = 0; 462 } 463 464 static void vhost_tx_batch(struct vhost_net *net, 465 struct vhost_net_virtqueue *nvq, 466 struct socket *sock, 467 struct msghdr *msghdr) 468 { 469 struct tun_msg_ctl ctl = { 470 .type = TUN_MSG_PTR, 471 .num = nvq->batched_xdp, 472 .ptr = nvq->xdp, 473 }; 474 int i, err; 475 476 if (nvq->batched_xdp == 0) 477 goto signal_used; 478 479 msghdr->msg_control = &ctl; 480 msghdr->msg_controllen = sizeof(ctl); 481 err = sock->ops->sendmsg(sock, msghdr, 0); 482 if (unlikely(err < 0)) { 483 vq_err(&nvq->vq, "Fail to batch sending packets\n"); 484 485 /* free pages owned by XDP; since this is an unlikely error path, 486 * keep it simple and avoid more complex bulk update for the 487 * used pages 488 */ 489 for (i = 0; i < nvq->batched_xdp; ++i) 490 put_page(virt_to_head_page(nvq->xdp[i].data)); 491 nvq->batched_xdp = 0; 492 nvq->done_idx = 0; 493 return; 494 } 495 496 signal_used: 497 vhost_net_signal_used(nvq); 498 nvq->batched_xdp = 0; 499 } 500 501 static int sock_has_rx_data(struct socket *sock) 502 { 503 if (unlikely(!sock)) 504 return 0; 505 506 if (sock->ops->peek_len) 507 return sock->ops->peek_len(sock); 508 509 return skb_queue_empty(&sock->sk->sk_receive_queue); 510 } 511 512 static void vhost_net_busy_poll_try_queue(struct vhost_net *net, 513 struct vhost_virtqueue *vq) 514 { 515 if (!vhost_vq_avail_empty(&net->dev, vq)) { 516 vhost_poll_queue(&vq->poll); 517 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 518 vhost_disable_notify(&net->dev, vq); 519 vhost_poll_queue(&vq->poll); 520 } 521 } 522 523 static void vhost_net_busy_poll(struct vhost_net *net, 524 struct vhost_virtqueue *rvq, 525 struct vhost_virtqueue *tvq, 526 bool *busyloop_intr, 527 bool poll_rx) 528 { 529 unsigned long busyloop_timeout; 530 unsigned long endtime; 531 struct socket *sock; 532 struct vhost_virtqueue *vq = poll_rx ? tvq : rvq; 533 534 /* Try to hold the vq mutex of the paired virtqueue. We can't 535 * use mutex_lock() here since we could not guarantee a 536 * consistenet lock ordering. 537 */ 538 if (!mutex_trylock(&vq->mutex)) 539 return; 540 541 vhost_disable_notify(&net->dev, vq); 542 sock = vhost_vq_get_backend(rvq); 543 544 busyloop_timeout = poll_rx ? rvq->busyloop_timeout: 545 tvq->busyloop_timeout; 546 547 preempt_disable(); 548 endtime = busy_clock() + busyloop_timeout; 549 550 while (vhost_can_busy_poll(endtime)) { 551 if (vhost_vq_has_work(vq)) { 552 *busyloop_intr = true; 553 break; 554 } 555 556 if ((sock_has_rx_data(sock) && 557 !vhost_vq_avail_empty(&net->dev, rvq)) || 558 !vhost_vq_avail_empty(&net->dev, tvq)) 559 break; 560 561 cpu_relax(); 562 } 563 564 preempt_enable(); 565 566 if (poll_rx || sock_has_rx_data(sock)) 567 vhost_net_busy_poll_try_queue(net, vq); 568 else if (!poll_rx) /* On tx here, sock has no rx data. */ 569 vhost_enable_notify(&net->dev, rvq); 570 571 mutex_unlock(&vq->mutex); 572 } 573 574 static int vhost_net_tx_get_vq_desc(struct vhost_net *net, 575 struct vhost_net_virtqueue *tnvq, 576 unsigned int *out_num, unsigned int *in_num, 577 struct msghdr *msghdr, bool *busyloop_intr) 578 { 579 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 580 struct vhost_virtqueue *rvq = &rnvq->vq; 581 struct vhost_virtqueue *tvq = &tnvq->vq; 582 583 int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), 584 out_num, in_num, NULL, NULL); 585 586 if (r == tvq->num && tvq->busyloop_timeout) { 587 /* Flush batched packets first */ 588 if (!vhost_sock_zcopy(vhost_vq_get_backend(tvq))) 589 vhost_tx_batch(net, tnvq, 590 vhost_vq_get_backend(tvq), 591 msghdr); 592 593 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false); 594 595 r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), 596 out_num, in_num, NULL, NULL); 597 } 598 599 return r; 600 } 601 602 static bool vhost_exceeds_maxpend(struct vhost_net *net) 603 { 604 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 605 struct vhost_virtqueue *vq = &nvq->vq; 606 607 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV > 608 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2); 609 } 610 611 static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter, 612 size_t hdr_size, int out) 613 { 614 /* Skip header. TODO: support TSO. */ 615 size_t len = iov_length(vq->iov, out); 616 617 iov_iter_init(iter, ITER_SOURCE, vq->iov, out, len); 618 iov_iter_advance(iter, hdr_size); 619 620 return iov_iter_count(iter); 621 } 622 623 static int get_tx_bufs(struct vhost_net *net, 624 struct vhost_net_virtqueue *nvq, 625 struct msghdr *msg, 626 unsigned int *out, unsigned int *in, 627 size_t *len, bool *busyloop_intr) 628 { 629 struct vhost_virtqueue *vq = &nvq->vq; 630 int ret; 631 632 ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr); 633 634 if (ret < 0 || ret == vq->num) 635 return ret; 636 637 if (*in) { 638 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n", 639 *out, *in); 640 return -EFAULT; 641 } 642 643 /* Sanity check */ 644 *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out); 645 if (*len == 0) { 646 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n", 647 *len, nvq->vhost_hlen); 648 return -EFAULT; 649 } 650 651 return ret; 652 } 653 654 static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len) 655 { 656 return total_len < VHOST_NET_WEIGHT && 657 !vhost_vq_avail_empty(vq->dev, vq); 658 } 659 660 #define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD) 661 662 static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, 663 struct iov_iter *from) 664 { 665 struct vhost_virtqueue *vq = &nvq->vq; 666 struct vhost_net *net = container_of(vq->dev, struct vhost_net, 667 dev); 668 struct socket *sock = vhost_vq_get_backend(vq); 669 struct virtio_net_hdr *gso; 670 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp]; 671 struct tun_xdp_hdr *hdr; 672 size_t len = iov_iter_count(from); 673 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0; 674 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 675 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen); 676 int sock_hlen = nvq->sock_hlen; 677 void *buf; 678 int copied; 679 int ret; 680 681 if (unlikely(len < nvq->sock_hlen)) 682 return -EFAULT; 683 684 if (SKB_DATA_ALIGN(len + pad) + 685 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE) 686 return -ENOSPC; 687 688 buflen += SKB_DATA_ALIGN(len + pad); 689 buf = page_frag_alloc_align(&net->pf_cache, buflen, GFP_KERNEL, 690 SMP_CACHE_BYTES); 691 if (unlikely(!buf)) 692 return -ENOMEM; 693 694 copied = copy_from_iter(buf + offsetof(struct tun_xdp_hdr, gso), 695 sock_hlen, from); 696 if (copied != sock_hlen) { 697 ret = -EFAULT; 698 goto err; 699 } 700 701 hdr = buf; 702 gso = &hdr->gso; 703 704 if (!sock_hlen) 705 memset(buf, 0, pad); 706 707 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 708 vhost16_to_cpu(vq, gso->csum_start) + 709 vhost16_to_cpu(vq, gso->csum_offset) + 2 > 710 vhost16_to_cpu(vq, gso->hdr_len)) { 711 gso->hdr_len = cpu_to_vhost16(vq, 712 vhost16_to_cpu(vq, gso->csum_start) + 713 vhost16_to_cpu(vq, gso->csum_offset) + 2); 714 715 if (vhost16_to_cpu(vq, gso->hdr_len) > len) { 716 ret = -EINVAL; 717 goto err; 718 } 719 } 720 721 len -= sock_hlen; 722 copied = copy_from_iter(buf + pad, len, from); 723 if (copied != len) { 724 ret = -EFAULT; 725 goto err; 726 } 727 728 xdp_init_buff(xdp, buflen, NULL); 729 xdp_prepare_buff(xdp, buf, pad, len, true); 730 hdr->buflen = buflen; 731 732 ++nvq->batched_xdp; 733 734 return 0; 735 736 err: 737 page_frag_free(buf); 738 return ret; 739 } 740 741 static void handle_tx_copy(struct vhost_net *net, struct socket *sock) 742 { 743 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 744 struct vhost_virtqueue *vq = &nvq->vq; 745 unsigned out, in; 746 int head; 747 struct msghdr msg = { 748 .msg_name = NULL, 749 .msg_namelen = 0, 750 .msg_control = NULL, 751 .msg_controllen = 0, 752 .msg_flags = MSG_DONTWAIT, 753 }; 754 size_t len, total_len = 0; 755 int err; 756 int sent_pkts = 0; 757 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX); 758 bool busyloop_intr; 759 760 do { 761 busyloop_intr = false; 762 if (nvq->done_idx == VHOST_NET_BATCH) 763 vhost_tx_batch(net, nvq, sock, &msg); 764 765 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 766 &busyloop_intr); 767 /* On error, stop handling until the next kick. */ 768 if (unlikely(head < 0)) 769 break; 770 /* Nothing new? Wait for eventfd to tell us they refilled. */ 771 if (head == vq->num) { 772 /* Kicks are disabled at this point, break loop and 773 * process any remaining batched packets. Queue will 774 * be re-enabled afterwards. 775 */ 776 break; 777 } 778 779 total_len += len; 780 781 /* For simplicity, TX batching is only enabled if 782 * sndbuf is unlimited. 783 */ 784 if (sock_can_batch) { 785 err = vhost_net_build_xdp(nvq, &msg.msg_iter); 786 if (!err) { 787 goto done; 788 } else if (unlikely(err != -ENOSPC)) { 789 vhost_tx_batch(net, nvq, sock, &msg); 790 vhost_discard_vq_desc(vq, 1); 791 vhost_net_enable_vq(net, vq); 792 break; 793 } 794 795 /* We can't build XDP buff, go for single 796 * packet path but let's flush batched 797 * packets. 798 */ 799 vhost_tx_batch(net, nvq, sock, &msg); 800 msg.msg_control = NULL; 801 } else { 802 if (tx_can_batch(vq, total_len)) 803 msg.msg_flags |= MSG_MORE; 804 else 805 msg.msg_flags &= ~MSG_MORE; 806 } 807 808 err = sock->ops->sendmsg(sock, &msg, len); 809 if (unlikely(err < 0)) { 810 if (err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS) { 811 vhost_discard_vq_desc(vq, 1); 812 vhost_net_enable_vq(net, vq); 813 break; 814 } 815 pr_debug("Fail to send packet: err %d", err); 816 } else if (unlikely(err != len)) 817 pr_debug("Truncated TX packet: len %d != %zd\n", 818 err, len); 819 done: 820 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head); 821 vq->heads[nvq->done_idx].len = 0; 822 ++nvq->done_idx; 823 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); 824 825 /* Kicks are still disabled, dispatch any remaining batched msgs. */ 826 vhost_tx_batch(net, nvq, sock, &msg); 827 828 if (unlikely(busyloop_intr)) 829 /* If interrupted while doing busy polling, requeue the 830 * handler to be fair handle_rx as well as other tasks 831 * waiting on cpu. 832 */ 833 vhost_poll_queue(&vq->poll); 834 else 835 /* All of our work has been completed; however, before 836 * leaving the TX handler, do one last check for work, 837 * and requeue handler if necessary. If there is no work, 838 * queue will be reenabled. 839 */ 840 vhost_net_busy_poll_try_queue(net, vq); 841 } 842 843 static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) 844 { 845 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 846 struct vhost_virtqueue *vq = &nvq->vq; 847 unsigned out, in; 848 int head; 849 struct msghdr msg = { 850 .msg_name = NULL, 851 .msg_namelen = 0, 852 .msg_control = NULL, 853 .msg_controllen = 0, 854 .msg_flags = MSG_DONTWAIT, 855 }; 856 struct tun_msg_ctl ctl; 857 size_t len, total_len = 0; 858 int err; 859 struct vhost_net_ubuf_ref *ubufs; 860 struct ubuf_info_msgzc *ubuf; 861 bool zcopy_used; 862 int sent_pkts = 0; 863 864 do { 865 bool busyloop_intr; 866 867 /* Release DMAs done buffers first */ 868 vhost_zerocopy_signal_used(net, vq); 869 870 busyloop_intr = false; 871 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 872 &busyloop_intr); 873 /* On error, stop handling until the next kick. */ 874 if (unlikely(head < 0)) 875 break; 876 /* Nothing new? Wait for eventfd to tell us they refilled. */ 877 if (head == vq->num) { 878 if (unlikely(busyloop_intr)) { 879 vhost_poll_queue(&vq->poll); 880 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 881 vhost_disable_notify(&net->dev, vq); 882 continue; 883 } 884 break; 885 } 886 887 zcopy_used = len >= VHOST_GOODCOPY_LEN 888 && !vhost_exceeds_maxpend(net) 889 && vhost_net_tx_select_zcopy(net); 890 891 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 892 if (zcopy_used) { 893 ubuf = nvq->ubuf_info + nvq->upend_idx; 894 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); 895 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; 896 ubuf->ctx = nvq->ubufs; 897 ubuf->desc = nvq->upend_idx; 898 ubuf->ubuf.ops = &vhost_ubuf_ops; 899 ubuf->ubuf.flags = SKBFL_ZEROCOPY_FRAG; 900 refcount_set(&ubuf->ubuf.refcnt, 1); 901 msg.msg_control = &ctl; 902 ctl.type = TUN_MSG_UBUF; 903 ctl.ptr = &ubuf->ubuf; 904 msg.msg_controllen = sizeof(ctl); 905 ubufs = nvq->ubufs; 906 atomic_inc(&ubufs->refcount); 907 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; 908 } else { 909 msg.msg_control = NULL; 910 ubufs = NULL; 911 } 912 total_len += len; 913 if (tx_can_batch(vq, total_len) && 914 likely(!vhost_exceeds_maxpend(net))) { 915 msg.msg_flags |= MSG_MORE; 916 } else { 917 msg.msg_flags &= ~MSG_MORE; 918 } 919 920 err = sock->ops->sendmsg(sock, &msg, len); 921 if (unlikely(err < 0)) { 922 bool retry = err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS; 923 924 if (zcopy_used) { 925 if (vq->heads[ubuf->desc].len == VHOST_DMA_IN_PROGRESS) 926 vhost_net_ubuf_put(ubufs); 927 if (retry) 928 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) 929 % UIO_MAXIOV; 930 else 931 vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN; 932 } 933 if (retry) { 934 vhost_discard_vq_desc(vq, 1); 935 vhost_net_enable_vq(net, vq); 936 break; 937 } 938 pr_debug("Fail to send packet: err %d", err); 939 } else if (unlikely(err != len)) 940 pr_debug("Truncated TX packet: " 941 " len %d != %zd\n", err, len); 942 if (!zcopy_used) 943 vhost_add_used_and_signal(&net->dev, vq, head, 0); 944 else 945 vhost_zerocopy_signal_used(net, vq); 946 vhost_net_tx_packet(net); 947 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); 948 } 949 950 /* Expects to be always run from workqueue - which acts as 951 * read-size critical section for our kind of RCU. */ 952 static void handle_tx(struct vhost_net *net) 953 { 954 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 955 struct vhost_virtqueue *vq = &nvq->vq; 956 struct socket *sock; 957 958 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_TX); 959 sock = vhost_vq_get_backend(vq); 960 if (!sock) 961 goto out; 962 963 if (!vq_meta_prefetch(vq)) 964 goto out; 965 966 vhost_disable_notify(&net->dev, vq); 967 vhost_net_disable_vq(net, vq); 968 969 if (vhost_sock_zcopy(sock)) 970 handle_tx_zerocopy(net, sock); 971 else 972 handle_tx_copy(net, sock); 973 974 out: 975 mutex_unlock(&vq->mutex); 976 } 977 978 static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk) 979 { 980 struct sk_buff *head; 981 int len = 0; 982 unsigned long flags; 983 984 if (rvq->rx_ring) 985 return vhost_net_buf_peek(rvq); 986 987 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); 988 head = skb_peek(&sk->sk_receive_queue); 989 if (likely(head)) { 990 len = head->len; 991 if (skb_vlan_tag_present(head)) 992 len += VLAN_HLEN; 993 } 994 995 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); 996 return len; 997 } 998 999 static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, 1000 bool *busyloop_intr) 1001 { 1002 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 1003 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX]; 1004 struct vhost_virtqueue *rvq = &rnvq->vq; 1005 struct vhost_virtqueue *tvq = &tnvq->vq; 1006 int len = peek_head_len(rnvq, sk); 1007 1008 if (!len && rvq->busyloop_timeout) { 1009 /* Flush batched heads first */ 1010 vhost_net_signal_used(rnvq); 1011 /* Both tx vq and rx socket were polled here */ 1012 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true); 1013 1014 len = peek_head_len(rnvq, sk); 1015 } 1016 1017 return len; 1018 } 1019 1020 /* This is a multi-buffer version of vhost_get_desc, that works if 1021 * vq has read descriptors only. 1022 * @vq - the relevant virtqueue 1023 * @datalen - data length we'll be reading 1024 * @iovcount - returned count of io vectors we fill 1025 * @log - vhost log 1026 * @log_num - log offset 1027 * @quota - headcount quota, 1 for big buffer 1028 * returns number of buffer heads allocated, negative on error 1029 */ 1030 static int get_rx_bufs(struct vhost_virtqueue *vq, 1031 struct vring_used_elem *heads, 1032 int datalen, 1033 unsigned *iovcount, 1034 struct vhost_log *log, 1035 unsigned *log_num, 1036 unsigned int quota) 1037 { 1038 unsigned int out, in; 1039 int seg = 0; 1040 int headcount = 0; 1041 unsigned d; 1042 int r, nlogs = 0; 1043 /* len is always initialized before use since we are always called with 1044 * datalen > 0. 1045 */ 1046 u32 len; 1047 1048 while (datalen > 0 && headcount < quota) { 1049 if (unlikely(seg >= UIO_MAXIOV)) { 1050 r = -ENOBUFS; 1051 goto err; 1052 } 1053 r = vhost_get_vq_desc(vq, vq->iov + seg, 1054 ARRAY_SIZE(vq->iov) - seg, &out, 1055 &in, log, log_num); 1056 if (unlikely(r < 0)) 1057 goto err; 1058 1059 d = r; 1060 if (d == vq->num) { 1061 r = 0; 1062 goto err; 1063 } 1064 if (unlikely(out || in <= 0)) { 1065 vq_err(vq, "unexpected descriptor format for RX: " 1066 "out %d, in %d\n", out, in); 1067 r = -EINVAL; 1068 goto err; 1069 } 1070 if (unlikely(log)) { 1071 nlogs += *log_num; 1072 log += *log_num; 1073 } 1074 heads[headcount].id = cpu_to_vhost32(vq, d); 1075 len = iov_length(vq->iov + seg, in); 1076 heads[headcount].len = cpu_to_vhost32(vq, len); 1077 datalen -= len; 1078 ++headcount; 1079 seg += in; 1080 } 1081 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); 1082 *iovcount = seg; 1083 if (unlikely(log)) 1084 *log_num = nlogs; 1085 1086 /* Detect overrun */ 1087 if (unlikely(datalen > 0)) { 1088 r = UIO_MAXIOV + 1; 1089 goto err; 1090 } 1091 return headcount; 1092 err: 1093 vhost_discard_vq_desc(vq, headcount); 1094 return r; 1095 } 1096 1097 /* Expects to be always run from workqueue - which acts as 1098 * read-size critical section for our kind of RCU. */ 1099 static void handle_rx(struct vhost_net *net) 1100 { 1101 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; 1102 struct vhost_virtqueue *vq = &nvq->vq; 1103 unsigned in, log; 1104 struct vhost_log *vq_log; 1105 struct msghdr msg = { 1106 .msg_name = NULL, 1107 .msg_namelen = 0, 1108 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 1109 .msg_controllen = 0, 1110 .msg_flags = MSG_DONTWAIT, 1111 }; 1112 struct virtio_net_hdr hdr = { 1113 .flags = 0, 1114 .gso_type = VIRTIO_NET_HDR_GSO_NONE 1115 }; 1116 size_t total_len = 0; 1117 int err, mergeable; 1118 s16 headcount; 1119 size_t vhost_hlen, sock_hlen; 1120 size_t vhost_len, sock_len; 1121 bool busyloop_intr = false; 1122 bool set_num_buffers; 1123 struct socket *sock; 1124 struct iov_iter fixup; 1125 __virtio16 num_buffers; 1126 int recv_pkts = 0; 1127 1128 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX); 1129 sock = vhost_vq_get_backend(vq); 1130 if (!sock) 1131 goto out; 1132 1133 if (!vq_meta_prefetch(vq)) 1134 goto out; 1135 1136 vhost_disable_notify(&net->dev, vq); 1137 vhost_net_disable_vq(net, vq); 1138 1139 vhost_hlen = nvq->vhost_hlen; 1140 sock_hlen = nvq->sock_hlen; 1141 1142 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ? 1143 vq->log : NULL; 1144 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); 1145 set_num_buffers = mergeable || 1146 vhost_has_feature(vq, VIRTIO_F_VERSION_1); 1147 1148 do { 1149 sock_len = vhost_net_rx_peek_head_len(net, sock->sk, 1150 &busyloop_intr); 1151 if (!sock_len) 1152 break; 1153 sock_len += sock_hlen; 1154 vhost_len = sock_len + vhost_hlen; 1155 headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx, 1156 vhost_len, &in, vq_log, &log, 1157 likely(mergeable) ? UIO_MAXIOV : 1); 1158 /* On error, stop handling until the next kick. */ 1159 if (unlikely(headcount < 0)) 1160 goto out; 1161 /* OK, now we need to know about added descriptors. */ 1162 if (!headcount) { 1163 if (unlikely(busyloop_intr)) { 1164 vhost_poll_queue(&vq->poll); 1165 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 1166 /* They have slipped one in as we were 1167 * doing that: check again. */ 1168 vhost_disable_notify(&net->dev, vq); 1169 continue; 1170 } 1171 /* Nothing new? Wait for eventfd to tell us 1172 * they refilled. */ 1173 goto out; 1174 } 1175 busyloop_intr = false; 1176 if (nvq->rx_ring) 1177 msg.msg_control = vhost_net_buf_consume(&nvq->rxq); 1178 /* On overrun, truncate and discard */ 1179 if (unlikely(headcount > UIO_MAXIOV)) { 1180 iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, 1, 1); 1181 err = sock->ops->recvmsg(sock, &msg, 1182 1, MSG_DONTWAIT | MSG_TRUNC); 1183 pr_debug("Discarded rx packet: len %zd\n", sock_len); 1184 continue; 1185 } 1186 /* We don't need to be notified again. */ 1187 iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, in, vhost_len); 1188 fixup = msg.msg_iter; 1189 if (unlikely((vhost_hlen))) { 1190 /* We will supply the header ourselves 1191 * TODO: support TSO. 1192 */ 1193 iov_iter_advance(&msg.msg_iter, vhost_hlen); 1194 } 1195 err = sock->ops->recvmsg(sock, &msg, 1196 sock_len, MSG_DONTWAIT | MSG_TRUNC); 1197 /* Userspace might have consumed the packet meanwhile: 1198 * it's not supposed to do this usually, but might be hard 1199 * to prevent. Discard data we got (if any) and keep going. */ 1200 if (unlikely(err != sock_len)) { 1201 pr_debug("Discarded rx packet: " 1202 " len %d, expected %zd\n", err, sock_len); 1203 vhost_discard_vq_desc(vq, headcount); 1204 continue; 1205 } 1206 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ 1207 if (unlikely(vhost_hlen)) { 1208 if (copy_to_iter(&hdr, sizeof(hdr), 1209 &fixup) != sizeof(hdr)) { 1210 vq_err(vq, "Unable to write vnet_hdr " 1211 "at addr %p\n", vq->iov->iov_base); 1212 goto out; 1213 } 1214 } else { 1215 /* Header came from socket; we'll need to patch 1216 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF 1217 */ 1218 iov_iter_advance(&fixup, sizeof(hdr)); 1219 } 1220 /* TODO: Should check and handle checksum. */ 1221 1222 num_buffers = cpu_to_vhost16(vq, headcount); 1223 if (likely(set_num_buffers) && 1224 copy_to_iter(&num_buffers, sizeof num_buffers, 1225 &fixup) != sizeof num_buffers) { 1226 vq_err(vq, "Failed num_buffers write"); 1227 vhost_discard_vq_desc(vq, headcount); 1228 goto out; 1229 } 1230 nvq->done_idx += headcount; 1231 if (nvq->done_idx > VHOST_NET_BATCH) 1232 vhost_net_signal_used(nvq); 1233 if (unlikely(vq_log)) 1234 vhost_log_write(vq, vq_log, log, vhost_len, 1235 vq->iov, in); 1236 total_len += vhost_len; 1237 } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len))); 1238 1239 if (unlikely(busyloop_intr)) 1240 vhost_poll_queue(&vq->poll); 1241 else if (!sock_len) 1242 vhost_net_enable_vq(net, vq); 1243 out: 1244 vhost_net_signal_used(nvq); 1245 mutex_unlock(&vq->mutex); 1246 } 1247 1248 static void handle_tx_kick(struct vhost_work *work) 1249 { 1250 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1251 poll.work); 1252 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1253 1254 handle_tx(net); 1255 } 1256 1257 static void handle_rx_kick(struct vhost_work *work) 1258 { 1259 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1260 poll.work); 1261 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1262 1263 handle_rx(net); 1264 } 1265 1266 static void handle_tx_net(struct vhost_work *work) 1267 { 1268 struct vhost_net *net = container_of(work, struct vhost_net, 1269 poll[VHOST_NET_VQ_TX].work); 1270 handle_tx(net); 1271 } 1272 1273 static void handle_rx_net(struct vhost_work *work) 1274 { 1275 struct vhost_net *net = container_of(work, struct vhost_net, 1276 poll[VHOST_NET_VQ_RX].work); 1277 handle_rx(net); 1278 } 1279 1280 static int vhost_net_open(struct inode *inode, struct file *f) 1281 { 1282 struct vhost_net *n; 1283 struct vhost_dev *dev; 1284 struct vhost_virtqueue **vqs; 1285 void **queue; 1286 struct xdp_buff *xdp; 1287 int i; 1288 1289 n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL); 1290 if (!n) 1291 return -ENOMEM; 1292 vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL); 1293 if (!vqs) { 1294 kvfree(n); 1295 return -ENOMEM; 1296 } 1297 1298 queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *), 1299 GFP_KERNEL); 1300 if (!queue) { 1301 kfree(vqs); 1302 kvfree(n); 1303 return -ENOMEM; 1304 } 1305 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue; 1306 1307 xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL); 1308 if (!xdp) { 1309 kfree(vqs); 1310 kvfree(n); 1311 kfree(queue); 1312 return -ENOMEM; 1313 } 1314 n->vqs[VHOST_NET_VQ_TX].xdp = xdp; 1315 1316 dev = &n->dev; 1317 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; 1318 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; 1319 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; 1320 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; 1321 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 1322 n->vqs[i].ubufs = NULL; 1323 n->vqs[i].ubuf_info = NULL; 1324 n->vqs[i].upend_idx = 0; 1325 n->vqs[i].done_idx = 0; 1326 n->vqs[i].batched_xdp = 0; 1327 n->vqs[i].vhost_hlen = 0; 1328 n->vqs[i].sock_hlen = 0; 1329 n->vqs[i].rx_ring = NULL; 1330 vhost_net_buf_init(&n->vqs[i].rxq); 1331 } 1332 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX, 1333 UIO_MAXIOV + VHOST_NET_BATCH, 1334 VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT, true, 1335 NULL); 1336 1337 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev, 1338 vqs[VHOST_NET_VQ_TX]); 1339 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev, 1340 vqs[VHOST_NET_VQ_RX]); 1341 1342 f->private_data = n; 1343 page_frag_cache_init(&n->pf_cache); 1344 1345 return 0; 1346 } 1347 1348 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 1349 struct vhost_virtqueue *vq) 1350 { 1351 struct socket *sock; 1352 struct vhost_net_virtqueue *nvq = 1353 container_of(vq, struct vhost_net_virtqueue, vq); 1354 1355 mutex_lock(&vq->mutex); 1356 sock = vhost_vq_get_backend(vq); 1357 vhost_net_disable_vq(n, vq); 1358 vhost_vq_set_backend(vq, NULL); 1359 vhost_net_buf_unproduce(nvq); 1360 nvq->rx_ring = NULL; 1361 mutex_unlock(&vq->mutex); 1362 return sock; 1363 } 1364 1365 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 1366 struct socket **rx_sock) 1367 { 1368 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); 1369 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); 1370 } 1371 1372 static void vhost_net_flush(struct vhost_net *n) 1373 { 1374 vhost_dev_flush(&n->dev); 1375 if (n->vqs[VHOST_NET_VQ_TX].ubufs) { 1376 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1377 n->tx_flush = true; 1378 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1379 /* Wait for all lower device DMAs done. */ 1380 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); 1381 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1382 n->tx_flush = false; 1383 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); 1384 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1385 } 1386 } 1387 1388 static int vhost_net_release(struct inode *inode, struct file *f) 1389 { 1390 struct vhost_net *n = f->private_data; 1391 struct socket *tx_sock; 1392 struct socket *rx_sock; 1393 1394 vhost_net_stop(n, &tx_sock, &rx_sock); 1395 vhost_net_flush(n); 1396 vhost_dev_stop(&n->dev); 1397 vhost_dev_cleanup(&n->dev); 1398 vhost_net_vq_reset(n); 1399 if (tx_sock) 1400 sockfd_put(tx_sock); 1401 if (rx_sock) 1402 sockfd_put(rx_sock); 1403 /* Make sure no callbacks are outstanding */ 1404 synchronize_rcu(); 1405 /* We do an extra flush before freeing memory, 1406 * since jobs can re-queue themselves. */ 1407 vhost_net_flush(n); 1408 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue); 1409 kfree(n->vqs[VHOST_NET_VQ_TX].xdp); 1410 kfree(n->dev.vqs); 1411 page_frag_cache_drain(&n->pf_cache); 1412 kvfree(n); 1413 return 0; 1414 } 1415 1416 static struct socket *get_raw_socket(int fd) 1417 { 1418 int r; 1419 struct socket *sock = sockfd_lookup(fd, &r); 1420 1421 if (!sock) 1422 return ERR_PTR(-ENOTSOCK); 1423 1424 /* Parameter checking */ 1425 if (sock->sk->sk_type != SOCK_RAW) { 1426 r = -ESOCKTNOSUPPORT; 1427 goto err; 1428 } 1429 1430 if (sock->sk->sk_family != AF_PACKET) { 1431 r = -EPFNOSUPPORT; 1432 goto err; 1433 } 1434 return sock; 1435 err: 1436 sockfd_put(sock); 1437 return ERR_PTR(r); 1438 } 1439 1440 static struct ptr_ring *get_tap_ptr_ring(struct file *file) 1441 { 1442 struct ptr_ring *ring; 1443 ring = tun_get_tx_ring(file); 1444 if (!IS_ERR(ring)) 1445 goto out; 1446 ring = tap_get_ptr_ring(file); 1447 if (!IS_ERR(ring)) 1448 goto out; 1449 ring = NULL; 1450 out: 1451 return ring; 1452 } 1453 1454 static struct socket *get_tap_socket(int fd) 1455 { 1456 struct file *file = fget(fd); 1457 struct socket *sock; 1458 1459 if (!file) 1460 return ERR_PTR(-EBADF); 1461 sock = tun_get_socket(file); 1462 if (!IS_ERR(sock)) 1463 return sock; 1464 sock = tap_get_socket(file); 1465 if (IS_ERR(sock)) 1466 fput(file); 1467 return sock; 1468 } 1469 1470 static struct socket *get_socket(int fd) 1471 { 1472 struct socket *sock; 1473 1474 /* special case to disable backend */ 1475 if (fd == -1) 1476 return NULL; 1477 sock = get_raw_socket(fd); 1478 if (!IS_ERR(sock)) 1479 return sock; 1480 sock = get_tap_socket(fd); 1481 if (!IS_ERR(sock)) 1482 return sock; 1483 return ERR_PTR(-ENOTSOCK); 1484 } 1485 1486 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 1487 { 1488 struct socket *sock, *oldsock; 1489 struct vhost_virtqueue *vq; 1490 struct vhost_net_virtqueue *nvq; 1491 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; 1492 int r; 1493 1494 mutex_lock(&n->dev.mutex); 1495 r = vhost_dev_check_owner(&n->dev); 1496 if (r) 1497 goto err; 1498 1499 if (index >= VHOST_NET_VQ_MAX) { 1500 r = -ENOBUFS; 1501 goto err; 1502 } 1503 vq = &n->vqs[index].vq; 1504 nvq = &n->vqs[index]; 1505 mutex_lock(&vq->mutex); 1506 1507 if (fd == -1) 1508 vhost_clear_msg(&n->dev); 1509 1510 /* Verify that ring has been setup correctly. */ 1511 if (!vhost_vq_access_ok(vq)) { 1512 r = -EFAULT; 1513 goto err_vq; 1514 } 1515 sock = get_socket(fd); 1516 if (IS_ERR(sock)) { 1517 r = PTR_ERR(sock); 1518 goto err_vq; 1519 } 1520 1521 /* start polling new socket */ 1522 oldsock = vhost_vq_get_backend(vq); 1523 if (sock != oldsock) { 1524 ubufs = vhost_net_ubuf_alloc(vq, 1525 sock && vhost_sock_zcopy(sock)); 1526 if (IS_ERR(ubufs)) { 1527 r = PTR_ERR(ubufs); 1528 goto err_ubufs; 1529 } 1530 1531 vhost_net_disable_vq(n, vq); 1532 vhost_vq_set_backend(vq, sock); 1533 vhost_net_buf_unproduce(nvq); 1534 r = vhost_vq_init_access(vq); 1535 if (r) 1536 goto err_used; 1537 r = vhost_net_enable_vq(n, vq); 1538 if (r) 1539 goto err_used; 1540 if (index == VHOST_NET_VQ_RX) { 1541 if (sock) 1542 nvq->rx_ring = get_tap_ptr_ring(sock->file); 1543 else 1544 nvq->rx_ring = NULL; 1545 } 1546 1547 oldubufs = nvq->ubufs; 1548 nvq->ubufs = ubufs; 1549 1550 n->tx_packets = 0; 1551 n->tx_zcopy_err = 0; 1552 n->tx_flush = false; 1553 } 1554 1555 mutex_unlock(&vq->mutex); 1556 1557 if (oldubufs) { 1558 vhost_net_ubuf_put_wait_and_free(oldubufs); 1559 mutex_lock(&vq->mutex); 1560 vhost_zerocopy_signal_used(n, vq); 1561 mutex_unlock(&vq->mutex); 1562 } 1563 1564 if (oldsock) { 1565 vhost_dev_flush(&n->dev); 1566 sockfd_put(oldsock); 1567 } 1568 1569 mutex_unlock(&n->dev.mutex); 1570 return 0; 1571 1572 err_used: 1573 vhost_vq_set_backend(vq, oldsock); 1574 vhost_net_enable_vq(n, vq); 1575 if (ubufs) 1576 vhost_net_ubuf_put_wait_and_free(ubufs); 1577 err_ubufs: 1578 if (sock) 1579 sockfd_put(sock); 1580 err_vq: 1581 mutex_unlock(&vq->mutex); 1582 err: 1583 mutex_unlock(&n->dev.mutex); 1584 return r; 1585 } 1586 1587 static long vhost_net_reset_owner(struct vhost_net *n) 1588 { 1589 struct socket *tx_sock = NULL; 1590 struct socket *rx_sock = NULL; 1591 long err; 1592 struct vhost_iotlb *umem; 1593 1594 mutex_lock(&n->dev.mutex); 1595 err = vhost_dev_check_owner(&n->dev); 1596 if (err) 1597 goto done; 1598 umem = vhost_dev_reset_owner_prepare(); 1599 if (!umem) { 1600 err = -ENOMEM; 1601 goto done; 1602 } 1603 vhost_net_stop(n, &tx_sock, &rx_sock); 1604 vhost_net_flush(n); 1605 vhost_dev_stop(&n->dev); 1606 vhost_dev_reset_owner(&n->dev, umem); 1607 vhost_net_vq_reset(n); 1608 done: 1609 mutex_unlock(&n->dev.mutex); 1610 if (tx_sock) 1611 sockfd_put(tx_sock); 1612 if (rx_sock) 1613 sockfd_put(rx_sock); 1614 return err; 1615 } 1616 1617 static int vhost_net_set_features(struct vhost_net *n, u64 features) 1618 { 1619 size_t vhost_hlen, sock_hlen, hdr_len; 1620 int i; 1621 1622 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | 1623 (1ULL << VIRTIO_F_VERSION_1))) ? 1624 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 1625 sizeof(struct virtio_net_hdr); 1626 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 1627 /* vhost provides vnet_hdr */ 1628 vhost_hlen = hdr_len; 1629 sock_hlen = 0; 1630 } else { 1631 /* socket provides vnet_hdr */ 1632 vhost_hlen = 0; 1633 sock_hlen = hdr_len; 1634 } 1635 mutex_lock(&n->dev.mutex); 1636 if ((features & (1 << VHOST_F_LOG_ALL)) && 1637 !vhost_log_access_ok(&n->dev)) 1638 goto out_unlock; 1639 1640 if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) { 1641 if (vhost_init_device_iotlb(&n->dev)) 1642 goto out_unlock; 1643 } 1644 1645 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1646 mutex_lock(&n->vqs[i].vq.mutex); 1647 n->vqs[i].vq.acked_features = features; 1648 n->vqs[i].vhost_hlen = vhost_hlen; 1649 n->vqs[i].sock_hlen = sock_hlen; 1650 mutex_unlock(&n->vqs[i].vq.mutex); 1651 } 1652 mutex_unlock(&n->dev.mutex); 1653 return 0; 1654 1655 out_unlock: 1656 mutex_unlock(&n->dev.mutex); 1657 return -EFAULT; 1658 } 1659 1660 static long vhost_net_set_owner(struct vhost_net *n) 1661 { 1662 int r; 1663 1664 mutex_lock(&n->dev.mutex); 1665 if (vhost_dev_has_owner(&n->dev)) { 1666 r = -EBUSY; 1667 goto out; 1668 } 1669 r = vhost_net_set_ubuf_info(n); 1670 if (r) 1671 goto out; 1672 r = vhost_dev_set_owner(&n->dev); 1673 if (r) 1674 vhost_net_clear_ubuf_info(n); 1675 vhost_net_flush(n); 1676 out: 1677 mutex_unlock(&n->dev.mutex); 1678 return r; 1679 } 1680 1681 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 1682 unsigned long arg) 1683 { 1684 struct vhost_net *n = f->private_data; 1685 void __user *argp = (void __user *)arg; 1686 u64 __user *featurep = argp; 1687 struct vhost_vring_file backend; 1688 u64 features; 1689 int r; 1690 1691 switch (ioctl) { 1692 case VHOST_NET_SET_BACKEND: 1693 if (copy_from_user(&backend, argp, sizeof backend)) 1694 return -EFAULT; 1695 return vhost_net_set_backend(n, backend.index, backend.fd); 1696 case VHOST_GET_FEATURES: 1697 features = VHOST_NET_FEATURES; 1698 if (copy_to_user(featurep, &features, sizeof features)) 1699 return -EFAULT; 1700 return 0; 1701 case VHOST_SET_FEATURES: 1702 if (copy_from_user(&features, featurep, sizeof features)) 1703 return -EFAULT; 1704 if (features & ~VHOST_NET_FEATURES) 1705 return -EOPNOTSUPP; 1706 return vhost_net_set_features(n, features); 1707 case VHOST_GET_BACKEND_FEATURES: 1708 features = VHOST_NET_BACKEND_FEATURES; 1709 if (copy_to_user(featurep, &features, sizeof(features))) 1710 return -EFAULT; 1711 return 0; 1712 case VHOST_SET_BACKEND_FEATURES: 1713 if (copy_from_user(&features, featurep, sizeof(features))) 1714 return -EFAULT; 1715 if (features & ~VHOST_NET_BACKEND_FEATURES) 1716 return -EOPNOTSUPP; 1717 vhost_set_backend_features(&n->dev, features); 1718 return 0; 1719 case VHOST_RESET_OWNER: 1720 return vhost_net_reset_owner(n); 1721 case VHOST_SET_OWNER: 1722 return vhost_net_set_owner(n); 1723 default: 1724 mutex_lock(&n->dev.mutex); 1725 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 1726 if (r == -ENOIOCTLCMD) 1727 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 1728 else 1729 vhost_net_flush(n); 1730 mutex_unlock(&n->dev.mutex); 1731 return r; 1732 } 1733 } 1734 1735 static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1736 { 1737 struct file *file = iocb->ki_filp; 1738 struct vhost_net *n = file->private_data; 1739 struct vhost_dev *dev = &n->dev; 1740 int noblock = file->f_flags & O_NONBLOCK; 1741 1742 return vhost_chr_read_iter(dev, to, noblock); 1743 } 1744 1745 static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb, 1746 struct iov_iter *from) 1747 { 1748 struct file *file = iocb->ki_filp; 1749 struct vhost_net *n = file->private_data; 1750 struct vhost_dev *dev = &n->dev; 1751 1752 return vhost_chr_write_iter(dev, from); 1753 } 1754 1755 static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait) 1756 { 1757 struct vhost_net *n = file->private_data; 1758 struct vhost_dev *dev = &n->dev; 1759 1760 return vhost_chr_poll(file, dev, wait); 1761 } 1762 1763 static const struct file_operations vhost_net_fops = { 1764 .owner = THIS_MODULE, 1765 .release = vhost_net_release, 1766 .read_iter = vhost_net_chr_read_iter, 1767 .write_iter = vhost_net_chr_write_iter, 1768 .poll = vhost_net_chr_poll, 1769 .unlocked_ioctl = vhost_net_ioctl, 1770 .compat_ioctl = compat_ptr_ioctl, 1771 .open = vhost_net_open, 1772 .llseek = noop_llseek, 1773 }; 1774 1775 static struct miscdevice vhost_net_misc = { 1776 .minor = VHOST_NET_MINOR, 1777 .name = "vhost-net", 1778 .fops = &vhost_net_fops, 1779 }; 1780 1781 static int __init vhost_net_init(void) 1782 { 1783 if (experimental_zcopytx) 1784 vhost_net_enable_zcopy(VHOST_NET_VQ_TX); 1785 return misc_register(&vhost_net_misc); 1786 } 1787 module_init(vhost_net_init); 1788 1789 static void __exit vhost_net_exit(void) 1790 { 1791 misc_deregister(&vhost_net_misc); 1792 } 1793 module_exit(vhost_net_exit); 1794 1795 MODULE_VERSION("0.0.1"); 1796 MODULE_LICENSE("GPL v2"); 1797 MODULE_AUTHOR("Michael S. Tsirkin"); 1798 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1799 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1800 MODULE_ALIAS("devname:vhost-net"); 1801