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_callback(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 inline unsigned long busy_clock(void) 412 { 413 return local_clock() >> 10; 414 } 415 416 static bool vhost_can_busy_poll(unsigned long endtime) 417 { 418 return likely(!need_resched() && !time_after(busy_clock(), endtime) && 419 !signal_pending(current)); 420 } 421 422 static void vhost_net_disable_vq(struct vhost_net *n, 423 struct vhost_virtqueue *vq) 424 { 425 struct vhost_net_virtqueue *nvq = 426 container_of(vq, struct vhost_net_virtqueue, vq); 427 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 428 if (!vhost_vq_get_backend(vq)) 429 return; 430 vhost_poll_stop(poll); 431 } 432 433 static int vhost_net_enable_vq(struct vhost_net *n, 434 struct vhost_virtqueue *vq) 435 { 436 struct vhost_net_virtqueue *nvq = 437 container_of(vq, struct vhost_net_virtqueue, vq); 438 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 439 struct socket *sock; 440 441 sock = vhost_vq_get_backend(vq); 442 if (!sock) 443 return 0; 444 445 return vhost_poll_start(poll, sock->file); 446 } 447 448 static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq) 449 { 450 struct vhost_virtqueue *vq = &nvq->vq; 451 struct vhost_dev *dev = vq->dev; 452 453 if (!nvq->done_idx) 454 return; 455 456 vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx); 457 nvq->done_idx = 0; 458 } 459 460 static void vhost_tx_batch(struct vhost_net *net, 461 struct vhost_net_virtqueue *nvq, 462 struct socket *sock, 463 struct msghdr *msghdr) 464 { 465 struct tun_msg_ctl ctl = { 466 .type = TUN_MSG_PTR, 467 .num = nvq->batched_xdp, 468 .ptr = nvq->xdp, 469 }; 470 int i, err; 471 472 if (nvq->batched_xdp == 0) 473 goto signal_used; 474 475 msghdr->msg_control = &ctl; 476 msghdr->msg_controllen = sizeof(ctl); 477 err = sock->ops->sendmsg(sock, msghdr, 0); 478 if (unlikely(err < 0)) { 479 vq_err(&nvq->vq, "Fail to batch sending packets\n"); 480 481 /* free pages owned by XDP; since this is an unlikely error path, 482 * keep it simple and avoid more complex bulk update for the 483 * used pages 484 */ 485 for (i = 0; i < nvq->batched_xdp; ++i) 486 put_page(virt_to_head_page(nvq->xdp[i].data)); 487 nvq->batched_xdp = 0; 488 nvq->done_idx = 0; 489 return; 490 } 491 492 signal_used: 493 vhost_net_signal_used(nvq); 494 nvq->batched_xdp = 0; 495 } 496 497 static int sock_has_rx_data(struct socket *sock) 498 { 499 if (unlikely(!sock)) 500 return 0; 501 502 if (sock->ops->peek_len) 503 return sock->ops->peek_len(sock); 504 505 return skb_queue_empty(&sock->sk->sk_receive_queue); 506 } 507 508 static void vhost_net_busy_poll_try_queue(struct vhost_net *net, 509 struct vhost_virtqueue *vq) 510 { 511 if (!vhost_vq_avail_empty(&net->dev, vq)) { 512 vhost_poll_queue(&vq->poll); 513 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 514 vhost_disable_notify(&net->dev, vq); 515 vhost_poll_queue(&vq->poll); 516 } 517 } 518 519 static void vhost_net_busy_poll(struct vhost_net *net, 520 struct vhost_virtqueue *rvq, 521 struct vhost_virtqueue *tvq, 522 bool *busyloop_intr, 523 bool poll_rx) 524 { 525 unsigned long busyloop_timeout; 526 unsigned long endtime; 527 struct socket *sock; 528 struct vhost_virtqueue *vq = poll_rx ? tvq : rvq; 529 530 /* Try to hold the vq mutex of the paired virtqueue. We can't 531 * use mutex_lock() here since we could not guarantee a 532 * consistenet lock ordering. 533 */ 534 if (!mutex_trylock(&vq->mutex)) 535 return; 536 537 vhost_disable_notify(&net->dev, vq); 538 sock = vhost_vq_get_backend(rvq); 539 540 busyloop_timeout = poll_rx ? rvq->busyloop_timeout: 541 tvq->busyloop_timeout; 542 543 preempt_disable(); 544 endtime = busy_clock() + busyloop_timeout; 545 546 while (vhost_can_busy_poll(endtime)) { 547 if (vhost_vq_has_work(vq)) { 548 *busyloop_intr = true; 549 break; 550 } 551 552 if ((sock_has_rx_data(sock) && 553 !vhost_vq_avail_empty(&net->dev, rvq)) || 554 !vhost_vq_avail_empty(&net->dev, tvq)) 555 break; 556 557 cpu_relax(); 558 } 559 560 preempt_enable(); 561 562 if (poll_rx || sock_has_rx_data(sock)) 563 vhost_net_busy_poll_try_queue(net, vq); 564 else if (!poll_rx) /* On tx here, sock has no rx data. */ 565 vhost_enable_notify(&net->dev, rvq); 566 567 mutex_unlock(&vq->mutex); 568 } 569 570 static int vhost_net_tx_get_vq_desc(struct vhost_net *net, 571 struct vhost_net_virtqueue *tnvq, 572 unsigned int *out_num, unsigned int *in_num, 573 struct msghdr *msghdr, bool *busyloop_intr) 574 { 575 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 576 struct vhost_virtqueue *rvq = &rnvq->vq; 577 struct vhost_virtqueue *tvq = &tnvq->vq; 578 579 int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), 580 out_num, in_num, NULL, NULL); 581 582 if (r == tvq->num && tvq->busyloop_timeout) { 583 /* Flush batched packets first */ 584 if (!vhost_sock_zcopy(vhost_vq_get_backend(tvq))) 585 vhost_tx_batch(net, tnvq, 586 vhost_vq_get_backend(tvq), 587 msghdr); 588 589 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false); 590 591 r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), 592 out_num, in_num, NULL, NULL); 593 } 594 595 return r; 596 } 597 598 static bool vhost_exceeds_maxpend(struct vhost_net *net) 599 { 600 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 601 struct vhost_virtqueue *vq = &nvq->vq; 602 603 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV > 604 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2); 605 } 606 607 static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter, 608 size_t hdr_size, int out) 609 { 610 /* Skip header. TODO: support TSO. */ 611 size_t len = iov_length(vq->iov, out); 612 613 iov_iter_init(iter, ITER_SOURCE, vq->iov, out, len); 614 iov_iter_advance(iter, hdr_size); 615 616 return iov_iter_count(iter); 617 } 618 619 static int get_tx_bufs(struct vhost_net *net, 620 struct vhost_net_virtqueue *nvq, 621 struct msghdr *msg, 622 unsigned int *out, unsigned int *in, 623 size_t *len, bool *busyloop_intr) 624 { 625 struct vhost_virtqueue *vq = &nvq->vq; 626 int ret; 627 628 ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr); 629 630 if (ret < 0 || ret == vq->num) 631 return ret; 632 633 if (*in) { 634 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n", 635 *out, *in); 636 return -EFAULT; 637 } 638 639 /* Sanity check */ 640 *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out); 641 if (*len == 0) { 642 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n", 643 *len, nvq->vhost_hlen); 644 return -EFAULT; 645 } 646 647 return ret; 648 } 649 650 static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len) 651 { 652 return total_len < VHOST_NET_WEIGHT && 653 !vhost_vq_avail_empty(vq->dev, vq); 654 } 655 656 #define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD) 657 658 static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, 659 struct iov_iter *from) 660 { 661 struct vhost_virtqueue *vq = &nvq->vq; 662 struct vhost_net *net = container_of(vq->dev, struct vhost_net, 663 dev); 664 struct socket *sock = vhost_vq_get_backend(vq); 665 struct virtio_net_hdr *gso; 666 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp]; 667 struct tun_xdp_hdr *hdr; 668 size_t len = iov_iter_count(from); 669 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0; 670 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 671 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen); 672 int sock_hlen = nvq->sock_hlen; 673 void *buf; 674 int copied; 675 int ret; 676 677 if (unlikely(len < nvq->sock_hlen)) 678 return -EFAULT; 679 680 if (SKB_DATA_ALIGN(len + pad) + 681 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE) 682 return -ENOSPC; 683 684 buflen += SKB_DATA_ALIGN(len + pad); 685 buf = page_frag_alloc_align(&net->pf_cache, buflen, GFP_KERNEL, 686 SMP_CACHE_BYTES); 687 if (unlikely(!buf)) 688 return -ENOMEM; 689 690 copied = copy_from_iter(buf + offsetof(struct tun_xdp_hdr, gso), 691 sock_hlen, from); 692 if (copied != sock_hlen) { 693 ret = -EFAULT; 694 goto err; 695 } 696 697 hdr = buf; 698 gso = &hdr->gso; 699 700 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 701 vhost16_to_cpu(vq, gso->csum_start) + 702 vhost16_to_cpu(vq, gso->csum_offset) + 2 > 703 vhost16_to_cpu(vq, gso->hdr_len)) { 704 gso->hdr_len = cpu_to_vhost16(vq, 705 vhost16_to_cpu(vq, gso->csum_start) + 706 vhost16_to_cpu(vq, gso->csum_offset) + 2); 707 708 if (vhost16_to_cpu(vq, gso->hdr_len) > len) { 709 ret = -EINVAL; 710 goto err; 711 } 712 } 713 714 len -= sock_hlen; 715 copied = copy_from_iter(buf + pad, len, from); 716 if (copied != len) { 717 ret = -EFAULT; 718 goto err; 719 } 720 721 xdp_init_buff(xdp, buflen, NULL); 722 xdp_prepare_buff(xdp, buf, pad, len, true); 723 hdr->buflen = buflen; 724 725 ++nvq->batched_xdp; 726 727 return 0; 728 729 err: 730 page_frag_free(buf); 731 return ret; 732 } 733 734 static void handle_tx_copy(struct vhost_net *net, struct socket *sock) 735 { 736 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 737 struct vhost_virtqueue *vq = &nvq->vq; 738 unsigned out, in; 739 int head; 740 struct msghdr msg = { 741 .msg_name = NULL, 742 .msg_namelen = 0, 743 .msg_control = NULL, 744 .msg_controllen = 0, 745 .msg_flags = MSG_DONTWAIT, 746 }; 747 size_t len, total_len = 0; 748 int err; 749 int sent_pkts = 0; 750 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX); 751 752 do { 753 bool busyloop_intr = false; 754 755 if (nvq->done_idx == VHOST_NET_BATCH) 756 vhost_tx_batch(net, nvq, sock, &msg); 757 758 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 759 &busyloop_intr); 760 /* On error, stop handling until the next kick. */ 761 if (unlikely(head < 0)) 762 break; 763 /* Nothing new? Wait for eventfd to tell us they refilled. */ 764 if (head == vq->num) { 765 if (unlikely(busyloop_intr)) { 766 vhost_poll_queue(&vq->poll); 767 } else if (unlikely(vhost_enable_notify(&net->dev, 768 vq))) { 769 vhost_disable_notify(&net->dev, vq); 770 continue; 771 } 772 break; 773 } 774 775 total_len += len; 776 777 /* For simplicity, TX batching is only enabled if 778 * sndbuf is unlimited. 779 */ 780 if (sock_can_batch) { 781 err = vhost_net_build_xdp(nvq, &msg.msg_iter); 782 if (!err) { 783 goto done; 784 } else if (unlikely(err != -ENOSPC)) { 785 vhost_tx_batch(net, nvq, sock, &msg); 786 vhost_discard_vq_desc(vq, 1); 787 vhost_net_enable_vq(net, vq); 788 break; 789 } 790 791 /* We can't build XDP buff, go for single 792 * packet path but let's flush batched 793 * packets. 794 */ 795 vhost_tx_batch(net, nvq, sock, &msg); 796 msg.msg_control = NULL; 797 } else { 798 if (tx_can_batch(vq, total_len)) 799 msg.msg_flags |= MSG_MORE; 800 else 801 msg.msg_flags &= ~MSG_MORE; 802 } 803 804 err = sock->ops->sendmsg(sock, &msg, len); 805 if (unlikely(err < 0)) { 806 if (err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS) { 807 vhost_discard_vq_desc(vq, 1); 808 vhost_net_enable_vq(net, vq); 809 break; 810 } 811 pr_debug("Fail to send packet: err %d", err); 812 } else if (unlikely(err != len)) 813 pr_debug("Truncated TX packet: len %d != %zd\n", 814 err, len); 815 done: 816 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head); 817 vq->heads[nvq->done_idx].len = 0; 818 ++nvq->done_idx; 819 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); 820 821 vhost_tx_batch(net, nvq, sock, &msg); 822 } 823 824 static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) 825 { 826 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 827 struct vhost_virtqueue *vq = &nvq->vq; 828 unsigned out, in; 829 int head; 830 struct msghdr msg = { 831 .msg_name = NULL, 832 .msg_namelen = 0, 833 .msg_control = NULL, 834 .msg_controllen = 0, 835 .msg_flags = MSG_DONTWAIT, 836 }; 837 struct tun_msg_ctl ctl; 838 size_t len, total_len = 0; 839 int err; 840 struct vhost_net_ubuf_ref *ubufs; 841 struct ubuf_info_msgzc *ubuf; 842 bool zcopy_used; 843 int sent_pkts = 0; 844 845 do { 846 bool busyloop_intr; 847 848 /* Release DMAs done buffers first */ 849 vhost_zerocopy_signal_used(net, vq); 850 851 busyloop_intr = false; 852 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 853 &busyloop_intr); 854 /* On error, stop handling until the next kick. */ 855 if (unlikely(head < 0)) 856 break; 857 /* Nothing new? Wait for eventfd to tell us they refilled. */ 858 if (head == vq->num) { 859 if (unlikely(busyloop_intr)) { 860 vhost_poll_queue(&vq->poll); 861 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 862 vhost_disable_notify(&net->dev, vq); 863 continue; 864 } 865 break; 866 } 867 868 zcopy_used = len >= VHOST_GOODCOPY_LEN 869 && !vhost_exceeds_maxpend(net) 870 && vhost_net_tx_select_zcopy(net); 871 872 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 873 if (zcopy_used) { 874 ubuf = nvq->ubuf_info + nvq->upend_idx; 875 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); 876 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; 877 ubuf->ctx = nvq->ubufs; 878 ubuf->desc = nvq->upend_idx; 879 ubuf->ubuf.callback = vhost_zerocopy_callback; 880 ubuf->ubuf.flags = SKBFL_ZEROCOPY_FRAG; 881 refcount_set(&ubuf->ubuf.refcnt, 1); 882 msg.msg_control = &ctl; 883 ctl.type = TUN_MSG_UBUF; 884 ctl.ptr = &ubuf->ubuf; 885 msg.msg_controllen = sizeof(ctl); 886 ubufs = nvq->ubufs; 887 atomic_inc(&ubufs->refcount); 888 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; 889 } else { 890 msg.msg_control = NULL; 891 ubufs = NULL; 892 } 893 total_len += len; 894 if (tx_can_batch(vq, total_len) && 895 likely(!vhost_exceeds_maxpend(net))) { 896 msg.msg_flags |= MSG_MORE; 897 } else { 898 msg.msg_flags &= ~MSG_MORE; 899 } 900 901 err = sock->ops->sendmsg(sock, &msg, len); 902 if (unlikely(err < 0)) { 903 bool retry = err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS; 904 905 if (zcopy_used) { 906 if (vq->heads[ubuf->desc].len == VHOST_DMA_IN_PROGRESS) 907 vhost_net_ubuf_put(ubufs); 908 if (retry) 909 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) 910 % UIO_MAXIOV; 911 else 912 vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN; 913 } 914 if (retry) { 915 vhost_discard_vq_desc(vq, 1); 916 vhost_net_enable_vq(net, vq); 917 break; 918 } 919 pr_debug("Fail to send packet: err %d", err); 920 } else if (unlikely(err != len)) 921 pr_debug("Truncated TX packet: " 922 " len %d != %zd\n", err, len); 923 if (!zcopy_used) 924 vhost_add_used_and_signal(&net->dev, vq, head, 0); 925 else 926 vhost_zerocopy_signal_used(net, vq); 927 vhost_net_tx_packet(net); 928 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); 929 } 930 931 /* Expects to be always run from workqueue - which acts as 932 * read-size critical section for our kind of RCU. */ 933 static void handle_tx(struct vhost_net *net) 934 { 935 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 936 struct vhost_virtqueue *vq = &nvq->vq; 937 struct socket *sock; 938 939 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_TX); 940 sock = vhost_vq_get_backend(vq); 941 if (!sock) 942 goto out; 943 944 if (!vq_meta_prefetch(vq)) 945 goto out; 946 947 vhost_disable_notify(&net->dev, vq); 948 vhost_net_disable_vq(net, vq); 949 950 if (vhost_sock_zcopy(sock)) 951 handle_tx_zerocopy(net, sock); 952 else 953 handle_tx_copy(net, sock); 954 955 out: 956 mutex_unlock(&vq->mutex); 957 } 958 959 static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk) 960 { 961 struct sk_buff *head; 962 int len = 0; 963 unsigned long flags; 964 965 if (rvq->rx_ring) 966 return vhost_net_buf_peek(rvq); 967 968 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); 969 head = skb_peek(&sk->sk_receive_queue); 970 if (likely(head)) { 971 len = head->len; 972 if (skb_vlan_tag_present(head)) 973 len += VLAN_HLEN; 974 } 975 976 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); 977 return len; 978 } 979 980 static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, 981 bool *busyloop_intr) 982 { 983 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 984 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX]; 985 struct vhost_virtqueue *rvq = &rnvq->vq; 986 struct vhost_virtqueue *tvq = &tnvq->vq; 987 int len = peek_head_len(rnvq, sk); 988 989 if (!len && rvq->busyloop_timeout) { 990 /* Flush batched heads first */ 991 vhost_net_signal_used(rnvq); 992 /* Both tx vq and rx socket were polled here */ 993 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true); 994 995 len = peek_head_len(rnvq, sk); 996 } 997 998 return len; 999 } 1000 1001 /* This is a multi-buffer version of vhost_get_desc, that works if 1002 * vq has read descriptors only. 1003 * @vq - the relevant virtqueue 1004 * @datalen - data length we'll be reading 1005 * @iovcount - returned count of io vectors we fill 1006 * @log - vhost log 1007 * @log_num - log offset 1008 * @quota - headcount quota, 1 for big buffer 1009 * returns number of buffer heads allocated, negative on error 1010 */ 1011 static int get_rx_bufs(struct vhost_virtqueue *vq, 1012 struct vring_used_elem *heads, 1013 int datalen, 1014 unsigned *iovcount, 1015 struct vhost_log *log, 1016 unsigned *log_num, 1017 unsigned int quota) 1018 { 1019 unsigned int out, in; 1020 int seg = 0; 1021 int headcount = 0; 1022 unsigned d; 1023 int r, nlogs = 0; 1024 /* len is always initialized before use since we are always called with 1025 * datalen > 0. 1026 */ 1027 u32 len; 1028 1029 while (datalen > 0 && headcount < quota) { 1030 if (unlikely(seg >= UIO_MAXIOV)) { 1031 r = -ENOBUFS; 1032 goto err; 1033 } 1034 r = vhost_get_vq_desc(vq, vq->iov + seg, 1035 ARRAY_SIZE(vq->iov) - seg, &out, 1036 &in, log, log_num); 1037 if (unlikely(r < 0)) 1038 goto err; 1039 1040 d = r; 1041 if (d == vq->num) { 1042 r = 0; 1043 goto err; 1044 } 1045 if (unlikely(out || in <= 0)) { 1046 vq_err(vq, "unexpected descriptor format for RX: " 1047 "out %d, in %d\n", out, in); 1048 r = -EINVAL; 1049 goto err; 1050 } 1051 if (unlikely(log)) { 1052 nlogs += *log_num; 1053 log += *log_num; 1054 } 1055 heads[headcount].id = cpu_to_vhost32(vq, d); 1056 len = iov_length(vq->iov + seg, in); 1057 heads[headcount].len = cpu_to_vhost32(vq, len); 1058 datalen -= len; 1059 ++headcount; 1060 seg += in; 1061 } 1062 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); 1063 *iovcount = seg; 1064 if (unlikely(log)) 1065 *log_num = nlogs; 1066 1067 /* Detect overrun */ 1068 if (unlikely(datalen > 0)) { 1069 r = UIO_MAXIOV + 1; 1070 goto err; 1071 } 1072 return headcount; 1073 err: 1074 vhost_discard_vq_desc(vq, headcount); 1075 return r; 1076 } 1077 1078 /* Expects to be always run from workqueue - which acts as 1079 * read-size critical section for our kind of RCU. */ 1080 static void handle_rx(struct vhost_net *net) 1081 { 1082 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; 1083 struct vhost_virtqueue *vq = &nvq->vq; 1084 unsigned in, log; 1085 struct vhost_log *vq_log; 1086 struct msghdr msg = { 1087 .msg_name = NULL, 1088 .msg_namelen = 0, 1089 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 1090 .msg_controllen = 0, 1091 .msg_flags = MSG_DONTWAIT, 1092 }; 1093 struct virtio_net_hdr hdr = { 1094 .flags = 0, 1095 .gso_type = VIRTIO_NET_HDR_GSO_NONE 1096 }; 1097 size_t total_len = 0; 1098 int err, mergeable; 1099 s16 headcount; 1100 size_t vhost_hlen, sock_hlen; 1101 size_t vhost_len, sock_len; 1102 bool busyloop_intr = false; 1103 struct socket *sock; 1104 struct iov_iter fixup; 1105 __virtio16 num_buffers; 1106 int recv_pkts = 0; 1107 1108 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX); 1109 sock = vhost_vq_get_backend(vq); 1110 if (!sock) 1111 goto out; 1112 1113 if (!vq_meta_prefetch(vq)) 1114 goto out; 1115 1116 vhost_disable_notify(&net->dev, vq); 1117 vhost_net_disable_vq(net, vq); 1118 1119 vhost_hlen = nvq->vhost_hlen; 1120 sock_hlen = nvq->sock_hlen; 1121 1122 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ? 1123 vq->log : NULL; 1124 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); 1125 1126 do { 1127 sock_len = vhost_net_rx_peek_head_len(net, sock->sk, 1128 &busyloop_intr); 1129 if (!sock_len) 1130 break; 1131 sock_len += sock_hlen; 1132 vhost_len = sock_len + vhost_hlen; 1133 headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx, 1134 vhost_len, &in, vq_log, &log, 1135 likely(mergeable) ? UIO_MAXIOV : 1); 1136 /* On error, stop handling until the next kick. */ 1137 if (unlikely(headcount < 0)) 1138 goto out; 1139 /* OK, now we need to know about added descriptors. */ 1140 if (!headcount) { 1141 if (unlikely(busyloop_intr)) { 1142 vhost_poll_queue(&vq->poll); 1143 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 1144 /* They have slipped one in as we were 1145 * doing that: check again. */ 1146 vhost_disable_notify(&net->dev, vq); 1147 continue; 1148 } 1149 /* Nothing new? Wait for eventfd to tell us 1150 * they refilled. */ 1151 goto out; 1152 } 1153 busyloop_intr = false; 1154 if (nvq->rx_ring) 1155 msg.msg_control = vhost_net_buf_consume(&nvq->rxq); 1156 /* On overrun, truncate and discard */ 1157 if (unlikely(headcount > UIO_MAXIOV)) { 1158 iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, 1, 1); 1159 err = sock->ops->recvmsg(sock, &msg, 1160 1, MSG_DONTWAIT | MSG_TRUNC); 1161 pr_debug("Discarded rx packet: len %zd\n", sock_len); 1162 continue; 1163 } 1164 /* We don't need to be notified again. */ 1165 iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, in, vhost_len); 1166 fixup = msg.msg_iter; 1167 if (unlikely((vhost_hlen))) { 1168 /* We will supply the header ourselves 1169 * TODO: support TSO. 1170 */ 1171 iov_iter_advance(&msg.msg_iter, vhost_hlen); 1172 } 1173 err = sock->ops->recvmsg(sock, &msg, 1174 sock_len, MSG_DONTWAIT | MSG_TRUNC); 1175 /* Userspace might have consumed the packet meanwhile: 1176 * it's not supposed to do this usually, but might be hard 1177 * to prevent. Discard data we got (if any) and keep going. */ 1178 if (unlikely(err != sock_len)) { 1179 pr_debug("Discarded rx packet: " 1180 " len %d, expected %zd\n", err, sock_len); 1181 vhost_discard_vq_desc(vq, headcount); 1182 continue; 1183 } 1184 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ 1185 if (unlikely(vhost_hlen)) { 1186 if (copy_to_iter(&hdr, sizeof(hdr), 1187 &fixup) != sizeof(hdr)) { 1188 vq_err(vq, "Unable to write vnet_hdr " 1189 "at addr %p\n", vq->iov->iov_base); 1190 goto out; 1191 } 1192 } else { 1193 /* Header came from socket; we'll need to patch 1194 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF 1195 */ 1196 iov_iter_advance(&fixup, sizeof(hdr)); 1197 } 1198 /* TODO: Should check and handle checksum. */ 1199 1200 num_buffers = cpu_to_vhost16(vq, headcount); 1201 if (likely(mergeable) && 1202 copy_to_iter(&num_buffers, sizeof num_buffers, 1203 &fixup) != sizeof num_buffers) { 1204 vq_err(vq, "Failed num_buffers write"); 1205 vhost_discard_vq_desc(vq, headcount); 1206 goto out; 1207 } 1208 nvq->done_idx += headcount; 1209 if (nvq->done_idx > VHOST_NET_BATCH) 1210 vhost_net_signal_used(nvq); 1211 if (unlikely(vq_log)) 1212 vhost_log_write(vq, vq_log, log, vhost_len, 1213 vq->iov, in); 1214 total_len += vhost_len; 1215 } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len))); 1216 1217 if (unlikely(busyloop_intr)) 1218 vhost_poll_queue(&vq->poll); 1219 else if (!sock_len) 1220 vhost_net_enable_vq(net, vq); 1221 out: 1222 vhost_net_signal_used(nvq); 1223 mutex_unlock(&vq->mutex); 1224 } 1225 1226 static void handle_tx_kick(struct vhost_work *work) 1227 { 1228 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1229 poll.work); 1230 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1231 1232 handle_tx(net); 1233 } 1234 1235 static void handle_rx_kick(struct vhost_work *work) 1236 { 1237 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1238 poll.work); 1239 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1240 1241 handle_rx(net); 1242 } 1243 1244 static void handle_tx_net(struct vhost_work *work) 1245 { 1246 struct vhost_net *net = container_of(work, struct vhost_net, 1247 poll[VHOST_NET_VQ_TX].work); 1248 handle_tx(net); 1249 } 1250 1251 static void handle_rx_net(struct vhost_work *work) 1252 { 1253 struct vhost_net *net = container_of(work, struct vhost_net, 1254 poll[VHOST_NET_VQ_RX].work); 1255 handle_rx(net); 1256 } 1257 1258 static int vhost_net_open(struct inode *inode, struct file *f) 1259 { 1260 struct vhost_net *n; 1261 struct vhost_dev *dev; 1262 struct vhost_virtqueue **vqs; 1263 void **queue; 1264 struct xdp_buff *xdp; 1265 int i; 1266 1267 n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL); 1268 if (!n) 1269 return -ENOMEM; 1270 vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL); 1271 if (!vqs) { 1272 kvfree(n); 1273 return -ENOMEM; 1274 } 1275 1276 queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *), 1277 GFP_KERNEL); 1278 if (!queue) { 1279 kfree(vqs); 1280 kvfree(n); 1281 return -ENOMEM; 1282 } 1283 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue; 1284 1285 xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL); 1286 if (!xdp) { 1287 kfree(vqs); 1288 kvfree(n); 1289 kfree(queue); 1290 return -ENOMEM; 1291 } 1292 n->vqs[VHOST_NET_VQ_TX].xdp = xdp; 1293 1294 dev = &n->dev; 1295 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; 1296 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; 1297 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; 1298 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; 1299 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 1300 n->vqs[i].ubufs = NULL; 1301 n->vqs[i].ubuf_info = NULL; 1302 n->vqs[i].upend_idx = 0; 1303 n->vqs[i].done_idx = 0; 1304 n->vqs[i].batched_xdp = 0; 1305 n->vqs[i].vhost_hlen = 0; 1306 n->vqs[i].sock_hlen = 0; 1307 n->vqs[i].rx_ring = NULL; 1308 vhost_net_buf_init(&n->vqs[i].rxq); 1309 } 1310 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX, 1311 UIO_MAXIOV + VHOST_NET_BATCH, 1312 VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT, true, 1313 NULL); 1314 1315 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev, 1316 vqs[VHOST_NET_VQ_TX]); 1317 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev, 1318 vqs[VHOST_NET_VQ_RX]); 1319 1320 f->private_data = n; 1321 n->pf_cache.va = NULL; 1322 1323 return 0; 1324 } 1325 1326 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 1327 struct vhost_virtqueue *vq) 1328 { 1329 struct socket *sock; 1330 struct vhost_net_virtqueue *nvq = 1331 container_of(vq, struct vhost_net_virtqueue, vq); 1332 1333 mutex_lock(&vq->mutex); 1334 sock = vhost_vq_get_backend(vq); 1335 vhost_net_disable_vq(n, vq); 1336 vhost_vq_set_backend(vq, NULL); 1337 vhost_net_buf_unproduce(nvq); 1338 nvq->rx_ring = NULL; 1339 mutex_unlock(&vq->mutex); 1340 return sock; 1341 } 1342 1343 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 1344 struct socket **rx_sock) 1345 { 1346 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); 1347 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); 1348 } 1349 1350 static void vhost_net_flush(struct vhost_net *n) 1351 { 1352 vhost_dev_flush(&n->dev); 1353 if (n->vqs[VHOST_NET_VQ_TX].ubufs) { 1354 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1355 n->tx_flush = true; 1356 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1357 /* Wait for all lower device DMAs done. */ 1358 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); 1359 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1360 n->tx_flush = false; 1361 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); 1362 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1363 } 1364 } 1365 1366 static int vhost_net_release(struct inode *inode, struct file *f) 1367 { 1368 struct vhost_net *n = f->private_data; 1369 struct socket *tx_sock; 1370 struct socket *rx_sock; 1371 1372 vhost_net_stop(n, &tx_sock, &rx_sock); 1373 vhost_net_flush(n); 1374 vhost_dev_stop(&n->dev); 1375 vhost_dev_cleanup(&n->dev); 1376 vhost_net_vq_reset(n); 1377 if (tx_sock) 1378 sockfd_put(tx_sock); 1379 if (rx_sock) 1380 sockfd_put(rx_sock); 1381 /* Make sure no callbacks are outstanding */ 1382 synchronize_rcu(); 1383 /* We do an extra flush before freeing memory, 1384 * since jobs can re-queue themselves. */ 1385 vhost_net_flush(n); 1386 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue); 1387 kfree(n->vqs[VHOST_NET_VQ_TX].xdp); 1388 kfree(n->dev.vqs); 1389 page_frag_cache_drain(&n->pf_cache); 1390 kvfree(n); 1391 return 0; 1392 } 1393 1394 static struct socket *get_raw_socket(int fd) 1395 { 1396 int r; 1397 struct socket *sock = sockfd_lookup(fd, &r); 1398 1399 if (!sock) 1400 return ERR_PTR(-ENOTSOCK); 1401 1402 /* Parameter checking */ 1403 if (sock->sk->sk_type != SOCK_RAW) { 1404 r = -ESOCKTNOSUPPORT; 1405 goto err; 1406 } 1407 1408 if (sock->sk->sk_family != AF_PACKET) { 1409 r = -EPFNOSUPPORT; 1410 goto err; 1411 } 1412 return sock; 1413 err: 1414 sockfd_put(sock); 1415 return ERR_PTR(r); 1416 } 1417 1418 static struct ptr_ring *get_tap_ptr_ring(struct file *file) 1419 { 1420 struct ptr_ring *ring; 1421 ring = tun_get_tx_ring(file); 1422 if (!IS_ERR(ring)) 1423 goto out; 1424 ring = tap_get_ptr_ring(file); 1425 if (!IS_ERR(ring)) 1426 goto out; 1427 ring = NULL; 1428 out: 1429 return ring; 1430 } 1431 1432 static struct socket *get_tap_socket(int fd) 1433 { 1434 struct file *file = fget(fd); 1435 struct socket *sock; 1436 1437 if (!file) 1438 return ERR_PTR(-EBADF); 1439 sock = tun_get_socket(file); 1440 if (!IS_ERR(sock)) 1441 return sock; 1442 sock = tap_get_socket(file); 1443 if (IS_ERR(sock)) 1444 fput(file); 1445 return sock; 1446 } 1447 1448 static struct socket *get_socket(int fd) 1449 { 1450 struct socket *sock; 1451 1452 /* special case to disable backend */ 1453 if (fd == -1) 1454 return NULL; 1455 sock = get_raw_socket(fd); 1456 if (!IS_ERR(sock)) 1457 return sock; 1458 sock = get_tap_socket(fd); 1459 if (!IS_ERR(sock)) 1460 return sock; 1461 return ERR_PTR(-ENOTSOCK); 1462 } 1463 1464 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 1465 { 1466 struct socket *sock, *oldsock; 1467 struct vhost_virtqueue *vq; 1468 struct vhost_net_virtqueue *nvq; 1469 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; 1470 int r; 1471 1472 mutex_lock(&n->dev.mutex); 1473 r = vhost_dev_check_owner(&n->dev); 1474 if (r) 1475 goto err; 1476 1477 if (index >= VHOST_NET_VQ_MAX) { 1478 r = -ENOBUFS; 1479 goto err; 1480 } 1481 vq = &n->vqs[index].vq; 1482 nvq = &n->vqs[index]; 1483 mutex_lock(&vq->mutex); 1484 1485 if (fd == -1) 1486 vhost_clear_msg(&n->dev); 1487 1488 /* Verify that ring has been setup correctly. */ 1489 if (!vhost_vq_access_ok(vq)) { 1490 r = -EFAULT; 1491 goto err_vq; 1492 } 1493 sock = get_socket(fd); 1494 if (IS_ERR(sock)) { 1495 r = PTR_ERR(sock); 1496 goto err_vq; 1497 } 1498 1499 /* start polling new socket */ 1500 oldsock = vhost_vq_get_backend(vq); 1501 if (sock != oldsock) { 1502 ubufs = vhost_net_ubuf_alloc(vq, 1503 sock && vhost_sock_zcopy(sock)); 1504 if (IS_ERR(ubufs)) { 1505 r = PTR_ERR(ubufs); 1506 goto err_ubufs; 1507 } 1508 1509 vhost_net_disable_vq(n, vq); 1510 vhost_vq_set_backend(vq, sock); 1511 vhost_net_buf_unproduce(nvq); 1512 r = vhost_vq_init_access(vq); 1513 if (r) 1514 goto err_used; 1515 r = vhost_net_enable_vq(n, vq); 1516 if (r) 1517 goto err_used; 1518 if (index == VHOST_NET_VQ_RX) { 1519 if (sock) 1520 nvq->rx_ring = get_tap_ptr_ring(sock->file); 1521 else 1522 nvq->rx_ring = NULL; 1523 } 1524 1525 oldubufs = nvq->ubufs; 1526 nvq->ubufs = ubufs; 1527 1528 n->tx_packets = 0; 1529 n->tx_zcopy_err = 0; 1530 n->tx_flush = false; 1531 } 1532 1533 mutex_unlock(&vq->mutex); 1534 1535 if (oldubufs) { 1536 vhost_net_ubuf_put_wait_and_free(oldubufs); 1537 mutex_lock(&vq->mutex); 1538 vhost_zerocopy_signal_used(n, vq); 1539 mutex_unlock(&vq->mutex); 1540 } 1541 1542 if (oldsock) { 1543 vhost_dev_flush(&n->dev); 1544 sockfd_put(oldsock); 1545 } 1546 1547 mutex_unlock(&n->dev.mutex); 1548 return 0; 1549 1550 err_used: 1551 vhost_vq_set_backend(vq, oldsock); 1552 vhost_net_enable_vq(n, vq); 1553 if (ubufs) 1554 vhost_net_ubuf_put_wait_and_free(ubufs); 1555 err_ubufs: 1556 if (sock) 1557 sockfd_put(sock); 1558 err_vq: 1559 mutex_unlock(&vq->mutex); 1560 err: 1561 mutex_unlock(&n->dev.mutex); 1562 return r; 1563 } 1564 1565 static long vhost_net_reset_owner(struct vhost_net *n) 1566 { 1567 struct socket *tx_sock = NULL; 1568 struct socket *rx_sock = NULL; 1569 long err; 1570 struct vhost_iotlb *umem; 1571 1572 mutex_lock(&n->dev.mutex); 1573 err = vhost_dev_check_owner(&n->dev); 1574 if (err) 1575 goto done; 1576 umem = vhost_dev_reset_owner_prepare(); 1577 if (!umem) { 1578 err = -ENOMEM; 1579 goto done; 1580 } 1581 vhost_net_stop(n, &tx_sock, &rx_sock); 1582 vhost_net_flush(n); 1583 vhost_dev_stop(&n->dev); 1584 vhost_dev_reset_owner(&n->dev, umem); 1585 vhost_net_vq_reset(n); 1586 done: 1587 mutex_unlock(&n->dev.mutex); 1588 if (tx_sock) 1589 sockfd_put(tx_sock); 1590 if (rx_sock) 1591 sockfd_put(rx_sock); 1592 return err; 1593 } 1594 1595 static int vhost_net_set_features(struct vhost_net *n, u64 features) 1596 { 1597 size_t vhost_hlen, sock_hlen, hdr_len; 1598 int i; 1599 1600 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | 1601 (1ULL << VIRTIO_F_VERSION_1))) ? 1602 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 1603 sizeof(struct virtio_net_hdr); 1604 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 1605 /* vhost provides vnet_hdr */ 1606 vhost_hlen = hdr_len; 1607 sock_hlen = 0; 1608 } else { 1609 /* socket provides vnet_hdr */ 1610 vhost_hlen = 0; 1611 sock_hlen = hdr_len; 1612 } 1613 mutex_lock(&n->dev.mutex); 1614 if ((features & (1 << VHOST_F_LOG_ALL)) && 1615 !vhost_log_access_ok(&n->dev)) 1616 goto out_unlock; 1617 1618 if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) { 1619 if (vhost_init_device_iotlb(&n->dev)) 1620 goto out_unlock; 1621 } 1622 1623 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1624 mutex_lock(&n->vqs[i].vq.mutex); 1625 n->vqs[i].vq.acked_features = features; 1626 n->vqs[i].vhost_hlen = vhost_hlen; 1627 n->vqs[i].sock_hlen = sock_hlen; 1628 mutex_unlock(&n->vqs[i].vq.mutex); 1629 } 1630 mutex_unlock(&n->dev.mutex); 1631 return 0; 1632 1633 out_unlock: 1634 mutex_unlock(&n->dev.mutex); 1635 return -EFAULT; 1636 } 1637 1638 static long vhost_net_set_owner(struct vhost_net *n) 1639 { 1640 int r; 1641 1642 mutex_lock(&n->dev.mutex); 1643 if (vhost_dev_has_owner(&n->dev)) { 1644 r = -EBUSY; 1645 goto out; 1646 } 1647 r = vhost_net_set_ubuf_info(n); 1648 if (r) 1649 goto out; 1650 r = vhost_dev_set_owner(&n->dev); 1651 if (r) 1652 vhost_net_clear_ubuf_info(n); 1653 vhost_net_flush(n); 1654 out: 1655 mutex_unlock(&n->dev.mutex); 1656 return r; 1657 } 1658 1659 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 1660 unsigned long arg) 1661 { 1662 struct vhost_net *n = f->private_data; 1663 void __user *argp = (void __user *)arg; 1664 u64 __user *featurep = argp; 1665 struct vhost_vring_file backend; 1666 u64 features; 1667 int r; 1668 1669 switch (ioctl) { 1670 case VHOST_NET_SET_BACKEND: 1671 if (copy_from_user(&backend, argp, sizeof backend)) 1672 return -EFAULT; 1673 return vhost_net_set_backend(n, backend.index, backend.fd); 1674 case VHOST_GET_FEATURES: 1675 features = VHOST_NET_FEATURES; 1676 if (copy_to_user(featurep, &features, sizeof features)) 1677 return -EFAULT; 1678 return 0; 1679 case VHOST_SET_FEATURES: 1680 if (copy_from_user(&features, featurep, sizeof features)) 1681 return -EFAULT; 1682 if (features & ~VHOST_NET_FEATURES) 1683 return -EOPNOTSUPP; 1684 return vhost_net_set_features(n, features); 1685 case VHOST_GET_BACKEND_FEATURES: 1686 features = VHOST_NET_BACKEND_FEATURES; 1687 if (copy_to_user(featurep, &features, sizeof(features))) 1688 return -EFAULT; 1689 return 0; 1690 case VHOST_SET_BACKEND_FEATURES: 1691 if (copy_from_user(&features, featurep, sizeof(features))) 1692 return -EFAULT; 1693 if (features & ~VHOST_NET_BACKEND_FEATURES) 1694 return -EOPNOTSUPP; 1695 vhost_set_backend_features(&n->dev, features); 1696 return 0; 1697 case VHOST_RESET_OWNER: 1698 return vhost_net_reset_owner(n); 1699 case VHOST_SET_OWNER: 1700 return vhost_net_set_owner(n); 1701 default: 1702 mutex_lock(&n->dev.mutex); 1703 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 1704 if (r == -ENOIOCTLCMD) 1705 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 1706 else 1707 vhost_net_flush(n); 1708 mutex_unlock(&n->dev.mutex); 1709 return r; 1710 } 1711 } 1712 1713 static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1714 { 1715 struct file *file = iocb->ki_filp; 1716 struct vhost_net *n = file->private_data; 1717 struct vhost_dev *dev = &n->dev; 1718 int noblock = file->f_flags & O_NONBLOCK; 1719 1720 return vhost_chr_read_iter(dev, to, noblock); 1721 } 1722 1723 static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb, 1724 struct iov_iter *from) 1725 { 1726 struct file *file = iocb->ki_filp; 1727 struct vhost_net *n = file->private_data; 1728 struct vhost_dev *dev = &n->dev; 1729 1730 return vhost_chr_write_iter(dev, from); 1731 } 1732 1733 static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait) 1734 { 1735 struct vhost_net *n = file->private_data; 1736 struct vhost_dev *dev = &n->dev; 1737 1738 return vhost_chr_poll(file, dev, wait); 1739 } 1740 1741 static const struct file_operations vhost_net_fops = { 1742 .owner = THIS_MODULE, 1743 .release = vhost_net_release, 1744 .read_iter = vhost_net_chr_read_iter, 1745 .write_iter = vhost_net_chr_write_iter, 1746 .poll = vhost_net_chr_poll, 1747 .unlocked_ioctl = vhost_net_ioctl, 1748 .compat_ioctl = compat_ptr_ioctl, 1749 .open = vhost_net_open, 1750 .llseek = noop_llseek, 1751 }; 1752 1753 static struct miscdevice vhost_net_misc = { 1754 .minor = VHOST_NET_MINOR, 1755 .name = "vhost-net", 1756 .fops = &vhost_net_fops, 1757 }; 1758 1759 static int __init vhost_net_init(void) 1760 { 1761 if (experimental_zcopytx) 1762 vhost_net_enable_zcopy(VHOST_NET_VQ_TX); 1763 return misc_register(&vhost_net_misc); 1764 } 1765 module_init(vhost_net_init); 1766 1767 static void __exit vhost_net_exit(void) 1768 { 1769 misc_deregister(&vhost_net_misc); 1770 } 1771 module_exit(vhost_net_exit); 1772 1773 MODULE_VERSION("0.0.1"); 1774 MODULE_LICENSE("GPL v2"); 1775 MODULE_AUTHOR("Michael S. Tsirkin"); 1776 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1777 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1778 MODULE_ALIAS("devname:vhost-net"); 1779