1 /* Copyright (C) 2009 Red Hat, Inc. 2 * Author: Michael S. Tsirkin <mst@redhat.com> 3 * 4 * This work is licensed under the terms of the GNU GPL, version 2. 5 * 6 * virtio-net server in host kernel. 7 */ 8 9 #include <linux/compat.h> 10 #include <linux/eventfd.h> 11 #include <linux/vhost.h> 12 #include <linux/virtio_net.h> 13 #include <linux/miscdevice.h> 14 #include <linux/module.h> 15 #include <linux/moduleparam.h> 16 #include <linux/mutex.h> 17 #include <linux/workqueue.h> 18 #include <linux/file.h> 19 #include <linux/slab.h> 20 #include <linux/sched/clock.h> 21 #include <linux/sched/signal.h> 22 #include <linux/vmalloc.h> 23 24 #include <linux/net.h> 25 #include <linux/if_packet.h> 26 #include <linux/if_arp.h> 27 #include <linux/if_tun.h> 28 #include <linux/if_macvlan.h> 29 #include <linux/if_tap.h> 30 #include <linux/if_vlan.h> 31 #include <linux/skb_array.h> 32 #include <linux/skbuff.h> 33 34 #include <net/sock.h> 35 #include <net/xdp.h> 36 37 #include "vhost.h" 38 39 static int experimental_zcopytx = 1; 40 module_param(experimental_zcopytx, int, 0444); 41 MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" 42 " 1 -Enable; 0 - Disable"); 43 44 /* Max number of bytes transferred before requeueing the job. 45 * Using this limit prevents one virtqueue from starving others. */ 46 #define VHOST_NET_WEIGHT 0x80000 47 48 /* Max number of packets transferred before requeueing the job. 49 * Using this limit prevents one virtqueue from starving others with small 50 * pkts. 51 */ 52 #define VHOST_NET_PKT_WEIGHT 256 53 54 /* MAX number of TX used buffers for outstanding zerocopy */ 55 #define VHOST_MAX_PEND 128 56 #define VHOST_GOODCOPY_LEN 256 57 58 /* 59 * For transmit, used buffer len is unused; we override it to track buffer 60 * status internally; used for zerocopy tx only. 61 */ 62 /* Lower device DMA failed */ 63 #define VHOST_DMA_FAILED_LEN ((__force __virtio32)3) 64 /* Lower device DMA done */ 65 #define VHOST_DMA_DONE_LEN ((__force __virtio32)2) 66 /* Lower device DMA in progress */ 67 #define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) 68 /* Buffer unused */ 69 #define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) 70 71 #define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) 72 73 enum { 74 VHOST_NET_FEATURES = VHOST_FEATURES | 75 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | 76 (1ULL << VIRTIO_NET_F_MRG_RXBUF) | 77 (1ULL << VIRTIO_F_IOMMU_PLATFORM) 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 *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 */ 145 struct page_frag page_frag; 146 /* Refcount bias of page frag */ 147 int refcnt_bias; 148 }; 149 150 static unsigned vhost_net_zcopy_mask __read_mostly; 151 152 static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq) 153 { 154 if (rxq->tail != rxq->head) 155 return rxq->queue[rxq->head]; 156 else 157 return NULL; 158 } 159 160 static int vhost_net_buf_get_size(struct vhost_net_buf *rxq) 161 { 162 return rxq->tail - rxq->head; 163 } 164 165 static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq) 166 { 167 return rxq->tail == rxq->head; 168 } 169 170 static void *vhost_net_buf_consume(struct vhost_net_buf *rxq) 171 { 172 void *ret = vhost_net_buf_get_ptr(rxq); 173 ++rxq->head; 174 return ret; 175 } 176 177 static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq) 178 { 179 struct vhost_net_buf *rxq = &nvq->rxq; 180 181 rxq->head = 0; 182 rxq->tail = ptr_ring_consume_batched(nvq->rx_ring, rxq->queue, 183 VHOST_NET_BATCH); 184 return rxq->tail; 185 } 186 187 static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq) 188 { 189 struct vhost_net_buf *rxq = &nvq->rxq; 190 191 if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) { 192 ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head, 193 vhost_net_buf_get_size(rxq), 194 tun_ptr_free); 195 rxq->head = rxq->tail = 0; 196 } 197 } 198 199 static int vhost_net_buf_peek_len(void *ptr) 200 { 201 if (tun_is_xdp_frame(ptr)) { 202 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr); 203 204 return xdpf->len; 205 } 206 207 return __skb_array_len_with_tag(ptr); 208 } 209 210 static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq) 211 { 212 struct vhost_net_buf *rxq = &nvq->rxq; 213 214 if (!vhost_net_buf_is_empty(rxq)) 215 goto out; 216 217 if (!vhost_net_buf_produce(nvq)) 218 return 0; 219 220 out: 221 return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq)); 222 } 223 224 static void vhost_net_buf_init(struct vhost_net_buf *rxq) 225 { 226 rxq->head = rxq->tail = 0; 227 } 228 229 static void vhost_net_enable_zcopy(int vq) 230 { 231 vhost_net_zcopy_mask |= 0x1 << vq; 232 } 233 234 static struct vhost_net_ubuf_ref * 235 vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy) 236 { 237 struct vhost_net_ubuf_ref *ubufs; 238 /* No zero copy backend? Nothing to count. */ 239 if (!zcopy) 240 return NULL; 241 ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL); 242 if (!ubufs) 243 return ERR_PTR(-ENOMEM); 244 atomic_set(&ubufs->refcount, 1); 245 init_waitqueue_head(&ubufs->wait); 246 ubufs->vq = vq; 247 return ubufs; 248 } 249 250 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs) 251 { 252 int r = atomic_sub_return(1, &ubufs->refcount); 253 if (unlikely(!r)) 254 wake_up(&ubufs->wait); 255 return r; 256 } 257 258 static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) 259 { 260 vhost_net_ubuf_put(ubufs); 261 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); 262 } 263 264 static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) 265 { 266 vhost_net_ubuf_put_and_wait(ubufs); 267 kfree(ubufs); 268 } 269 270 static void vhost_net_clear_ubuf_info(struct vhost_net *n) 271 { 272 int i; 273 274 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 275 kfree(n->vqs[i].ubuf_info); 276 n->vqs[i].ubuf_info = NULL; 277 } 278 } 279 280 static int vhost_net_set_ubuf_info(struct vhost_net *n) 281 { 282 bool zcopy; 283 int i; 284 285 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 286 zcopy = vhost_net_zcopy_mask & (0x1 << i); 287 if (!zcopy) 288 continue; 289 n->vqs[i].ubuf_info = 290 kmalloc_array(UIO_MAXIOV, 291 sizeof(*n->vqs[i].ubuf_info), 292 GFP_KERNEL); 293 if (!n->vqs[i].ubuf_info) 294 goto err; 295 } 296 return 0; 297 298 err: 299 vhost_net_clear_ubuf_info(n); 300 return -ENOMEM; 301 } 302 303 static void vhost_net_vq_reset(struct vhost_net *n) 304 { 305 int i; 306 307 vhost_net_clear_ubuf_info(n); 308 309 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 310 n->vqs[i].done_idx = 0; 311 n->vqs[i].upend_idx = 0; 312 n->vqs[i].ubufs = NULL; 313 n->vqs[i].vhost_hlen = 0; 314 n->vqs[i].sock_hlen = 0; 315 vhost_net_buf_init(&n->vqs[i].rxq); 316 } 317 318 } 319 320 static void vhost_net_tx_packet(struct vhost_net *net) 321 { 322 ++net->tx_packets; 323 if (net->tx_packets < 1024) 324 return; 325 net->tx_packets = 0; 326 net->tx_zcopy_err = 0; 327 } 328 329 static void vhost_net_tx_err(struct vhost_net *net) 330 { 331 ++net->tx_zcopy_err; 332 } 333 334 static bool vhost_net_tx_select_zcopy(struct vhost_net *net) 335 { 336 /* TX flush waits for outstanding DMAs to be done. 337 * Don't start new DMAs. 338 */ 339 return !net->tx_flush && 340 net->tx_packets / 64 >= net->tx_zcopy_err; 341 } 342 343 static bool vhost_sock_zcopy(struct socket *sock) 344 { 345 return unlikely(experimental_zcopytx) && 346 sock_flag(sock->sk, SOCK_ZEROCOPY); 347 } 348 349 static bool vhost_sock_xdp(struct socket *sock) 350 { 351 return sock_flag(sock->sk, SOCK_XDP); 352 } 353 354 /* In case of DMA done not in order in lower device driver for some reason. 355 * upend_idx is used to track end of used idx, done_idx is used to track head 356 * of used idx. Once lower device DMA done contiguously, we will signal KVM 357 * guest used idx. 358 */ 359 static void vhost_zerocopy_signal_used(struct vhost_net *net, 360 struct vhost_virtqueue *vq) 361 { 362 struct vhost_net_virtqueue *nvq = 363 container_of(vq, struct vhost_net_virtqueue, vq); 364 int i, add; 365 int j = 0; 366 367 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { 368 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) 369 vhost_net_tx_err(net); 370 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { 371 vq->heads[i].len = VHOST_DMA_CLEAR_LEN; 372 ++j; 373 } else 374 break; 375 } 376 while (j) { 377 add = min(UIO_MAXIOV - nvq->done_idx, j); 378 vhost_add_used_and_signal_n(vq->dev, vq, 379 &vq->heads[nvq->done_idx], add); 380 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; 381 j -= add; 382 } 383 } 384 385 static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) 386 { 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 (!vq->private_data) 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 = vq->private_data; 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 err; 471 472 if (nvq->batched_xdp == 0) 473 goto signal_used; 474 475 msghdr->msg_control = &ctl; 476 err = sock->ops->sendmsg(sock, msghdr, 0); 477 if (unlikely(err < 0)) { 478 vq_err(&nvq->vq, "Fail to batch sending packets\n"); 479 return; 480 } 481 482 signal_used: 483 vhost_net_signal_used(nvq); 484 nvq->batched_xdp = 0; 485 } 486 487 static int sock_has_rx_data(struct socket *sock) 488 { 489 if (unlikely(!sock)) 490 return 0; 491 492 if (sock->ops->peek_len) 493 return sock->ops->peek_len(sock); 494 495 return skb_queue_empty(&sock->sk->sk_receive_queue); 496 } 497 498 static void vhost_net_busy_poll_try_queue(struct vhost_net *net, 499 struct vhost_virtqueue *vq) 500 { 501 if (!vhost_vq_avail_empty(&net->dev, vq)) { 502 vhost_poll_queue(&vq->poll); 503 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 504 vhost_disable_notify(&net->dev, vq); 505 vhost_poll_queue(&vq->poll); 506 } 507 } 508 509 static void vhost_net_busy_poll(struct vhost_net *net, 510 struct vhost_virtqueue *rvq, 511 struct vhost_virtqueue *tvq, 512 bool *busyloop_intr, 513 bool poll_rx) 514 { 515 unsigned long busyloop_timeout; 516 unsigned long endtime; 517 struct socket *sock; 518 struct vhost_virtqueue *vq = poll_rx ? tvq : rvq; 519 520 /* Try to hold the vq mutex of the paired virtqueue. We can't 521 * use mutex_lock() here since we could not guarantee a 522 * consistenet lock ordering. 523 */ 524 if (!mutex_trylock(&vq->mutex)) 525 return; 526 527 vhost_disable_notify(&net->dev, vq); 528 sock = rvq->private_data; 529 530 busyloop_timeout = poll_rx ? rvq->busyloop_timeout: 531 tvq->busyloop_timeout; 532 533 preempt_disable(); 534 endtime = busy_clock() + busyloop_timeout; 535 536 while (vhost_can_busy_poll(endtime)) { 537 if (vhost_has_work(&net->dev)) { 538 *busyloop_intr = true; 539 break; 540 } 541 542 if ((sock_has_rx_data(sock) && 543 !vhost_vq_avail_empty(&net->dev, rvq)) || 544 !vhost_vq_avail_empty(&net->dev, tvq)) 545 break; 546 547 cpu_relax(); 548 } 549 550 preempt_enable(); 551 552 if (poll_rx || sock_has_rx_data(sock)) 553 vhost_net_busy_poll_try_queue(net, vq); 554 else if (!poll_rx) /* On tx here, sock has no rx data. */ 555 vhost_enable_notify(&net->dev, rvq); 556 557 mutex_unlock(&vq->mutex); 558 } 559 560 static int vhost_net_tx_get_vq_desc(struct vhost_net *net, 561 struct vhost_net_virtqueue *tnvq, 562 unsigned int *out_num, unsigned int *in_num, 563 struct msghdr *msghdr, bool *busyloop_intr) 564 { 565 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 566 struct vhost_virtqueue *rvq = &rnvq->vq; 567 struct vhost_virtqueue *tvq = &tnvq->vq; 568 569 int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), 570 out_num, in_num, NULL, NULL); 571 572 if (r == tvq->num && tvq->busyloop_timeout) { 573 /* Flush batched packets first */ 574 if (!vhost_sock_zcopy(tvq->private_data)) 575 vhost_tx_batch(net, tnvq, tvq->private_data, msghdr); 576 577 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false); 578 579 r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), 580 out_num, in_num, NULL, NULL); 581 } 582 583 return r; 584 } 585 586 static bool vhost_exceeds_maxpend(struct vhost_net *net) 587 { 588 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 589 struct vhost_virtqueue *vq = &nvq->vq; 590 591 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV > 592 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2); 593 } 594 595 static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter, 596 size_t hdr_size, int out) 597 { 598 /* Skip header. TODO: support TSO. */ 599 size_t len = iov_length(vq->iov, out); 600 601 iov_iter_init(iter, WRITE, vq->iov, out, len); 602 iov_iter_advance(iter, hdr_size); 603 604 return iov_iter_count(iter); 605 } 606 607 static int get_tx_bufs(struct vhost_net *net, 608 struct vhost_net_virtqueue *nvq, 609 struct msghdr *msg, 610 unsigned int *out, unsigned int *in, 611 size_t *len, bool *busyloop_intr) 612 { 613 struct vhost_virtqueue *vq = &nvq->vq; 614 int ret; 615 616 ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr); 617 618 if (ret < 0 || ret == vq->num) 619 return ret; 620 621 if (*in) { 622 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n", 623 *out, *in); 624 return -EFAULT; 625 } 626 627 /* Sanity check */ 628 *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out); 629 if (*len == 0) { 630 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n", 631 *len, nvq->vhost_hlen); 632 return -EFAULT; 633 } 634 635 return ret; 636 } 637 638 static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len) 639 { 640 return total_len < VHOST_NET_WEIGHT && 641 !vhost_vq_avail_empty(vq->dev, vq); 642 } 643 644 #define SKB_FRAG_PAGE_ORDER get_order(32768) 645 646 static bool vhost_net_page_frag_refill(struct vhost_net *net, unsigned int sz, 647 struct page_frag *pfrag, gfp_t gfp) 648 { 649 if (pfrag->page) { 650 if (pfrag->offset + sz <= pfrag->size) 651 return true; 652 __page_frag_cache_drain(pfrag->page, net->refcnt_bias); 653 } 654 655 pfrag->offset = 0; 656 net->refcnt_bias = 0; 657 if (SKB_FRAG_PAGE_ORDER) { 658 /* Avoid direct reclaim but allow kswapd to wake */ 659 pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) | 660 __GFP_COMP | __GFP_NOWARN | 661 __GFP_NORETRY, 662 SKB_FRAG_PAGE_ORDER); 663 if (likely(pfrag->page)) { 664 pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER; 665 goto done; 666 } 667 } 668 pfrag->page = alloc_page(gfp); 669 if (likely(pfrag->page)) { 670 pfrag->size = PAGE_SIZE; 671 goto done; 672 } 673 return false; 674 675 done: 676 net->refcnt_bias = USHRT_MAX; 677 page_ref_add(pfrag->page, USHRT_MAX - 1); 678 return true; 679 } 680 681 #define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD) 682 683 static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, 684 struct iov_iter *from) 685 { 686 struct vhost_virtqueue *vq = &nvq->vq; 687 struct vhost_net *net = container_of(vq->dev, struct vhost_net, 688 dev); 689 struct socket *sock = vq->private_data; 690 struct page_frag *alloc_frag = &net->page_frag; 691 struct virtio_net_hdr *gso; 692 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp]; 693 struct tun_xdp_hdr *hdr; 694 size_t len = iov_iter_count(from); 695 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0; 696 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 697 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen); 698 int sock_hlen = nvq->sock_hlen; 699 void *buf; 700 int copied; 701 702 if (unlikely(len < nvq->sock_hlen)) 703 return -EFAULT; 704 705 if (SKB_DATA_ALIGN(len + pad) + 706 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE) 707 return -ENOSPC; 708 709 buflen += SKB_DATA_ALIGN(len + pad); 710 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES); 711 if (unlikely(!vhost_net_page_frag_refill(net, buflen, 712 alloc_frag, GFP_KERNEL))) 713 return -ENOMEM; 714 715 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset; 716 copied = copy_page_from_iter(alloc_frag->page, 717 alloc_frag->offset + 718 offsetof(struct tun_xdp_hdr, gso), 719 sock_hlen, from); 720 if (copied != sock_hlen) 721 return -EFAULT; 722 723 hdr = buf; 724 gso = &hdr->gso; 725 726 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 727 vhost16_to_cpu(vq, gso->csum_start) + 728 vhost16_to_cpu(vq, gso->csum_offset) + 2 > 729 vhost16_to_cpu(vq, gso->hdr_len)) { 730 gso->hdr_len = cpu_to_vhost16(vq, 731 vhost16_to_cpu(vq, gso->csum_start) + 732 vhost16_to_cpu(vq, gso->csum_offset) + 2); 733 734 if (vhost16_to_cpu(vq, gso->hdr_len) > len) 735 return -EINVAL; 736 } 737 738 len -= sock_hlen; 739 copied = copy_page_from_iter(alloc_frag->page, 740 alloc_frag->offset + pad, 741 len, from); 742 if (copied != len) 743 return -EFAULT; 744 745 xdp->data_hard_start = buf; 746 xdp->data = buf + pad; 747 xdp->data_end = xdp->data + len; 748 hdr->buflen = buflen; 749 750 --net->refcnt_bias; 751 alloc_frag->offset += buflen; 752 753 ++nvq->batched_xdp; 754 755 return 0; 756 } 757 758 static void handle_tx_copy(struct vhost_net *net, struct socket *sock) 759 { 760 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 761 struct vhost_virtqueue *vq = &nvq->vq; 762 unsigned out, in; 763 int head; 764 struct msghdr msg = { 765 .msg_name = NULL, 766 .msg_namelen = 0, 767 .msg_control = NULL, 768 .msg_controllen = 0, 769 .msg_flags = MSG_DONTWAIT, 770 }; 771 size_t len, total_len = 0; 772 int err; 773 int sent_pkts = 0; 774 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX); 775 776 do { 777 bool busyloop_intr = false; 778 779 if (nvq->done_idx == VHOST_NET_BATCH) 780 vhost_tx_batch(net, nvq, sock, &msg); 781 782 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 783 &busyloop_intr); 784 /* On error, stop handling until the next kick. */ 785 if (unlikely(head < 0)) 786 break; 787 /* Nothing new? Wait for eventfd to tell us they refilled. */ 788 if (head == vq->num) { 789 if (unlikely(busyloop_intr)) { 790 vhost_poll_queue(&vq->poll); 791 } else if (unlikely(vhost_enable_notify(&net->dev, 792 vq))) { 793 vhost_disable_notify(&net->dev, vq); 794 continue; 795 } 796 break; 797 } 798 799 total_len += len; 800 801 /* For simplicity, TX batching is only enabled if 802 * sndbuf is unlimited. 803 */ 804 if (sock_can_batch) { 805 err = vhost_net_build_xdp(nvq, &msg.msg_iter); 806 if (!err) { 807 goto done; 808 } else if (unlikely(err != -ENOSPC)) { 809 vhost_tx_batch(net, nvq, sock, &msg); 810 vhost_discard_vq_desc(vq, 1); 811 vhost_net_enable_vq(net, vq); 812 break; 813 } 814 815 /* We can't build XDP buff, go for single 816 * packet path but let's flush batched 817 * packets. 818 */ 819 vhost_tx_batch(net, nvq, sock, &msg); 820 msg.msg_control = NULL; 821 } else { 822 if (tx_can_batch(vq, total_len)) 823 msg.msg_flags |= MSG_MORE; 824 else 825 msg.msg_flags &= ~MSG_MORE; 826 } 827 828 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 829 err = sock->ops->sendmsg(sock, &msg, len); 830 if (unlikely(err < 0)) { 831 vhost_discard_vq_desc(vq, 1); 832 vhost_net_enable_vq(net, vq); 833 break; 834 } 835 if (err != len) 836 pr_debug("Truncated TX packet: len %d != %zd\n", 837 err, len); 838 done: 839 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head); 840 vq->heads[nvq->done_idx].len = 0; 841 ++nvq->done_idx; 842 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); 843 844 vhost_tx_batch(net, nvq, sock, &msg); 845 } 846 847 static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) 848 { 849 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 850 struct vhost_virtqueue *vq = &nvq->vq; 851 unsigned out, in; 852 int head; 853 struct msghdr msg = { 854 .msg_name = NULL, 855 .msg_namelen = 0, 856 .msg_control = NULL, 857 .msg_controllen = 0, 858 .msg_flags = MSG_DONTWAIT, 859 }; 860 struct tun_msg_ctl ctl; 861 size_t len, total_len = 0; 862 int err; 863 struct vhost_net_ubuf_ref *uninitialized_var(ubufs); 864 bool zcopy_used; 865 int sent_pkts = 0; 866 867 do { 868 bool busyloop_intr; 869 870 /* Release DMAs done buffers first */ 871 vhost_zerocopy_signal_used(net, vq); 872 873 busyloop_intr = false; 874 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 875 &busyloop_intr); 876 /* On error, stop handling until the next kick. */ 877 if (unlikely(head < 0)) 878 break; 879 /* Nothing new? Wait for eventfd to tell us they refilled. */ 880 if (head == vq->num) { 881 if (unlikely(busyloop_intr)) { 882 vhost_poll_queue(&vq->poll); 883 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 884 vhost_disable_notify(&net->dev, vq); 885 continue; 886 } 887 break; 888 } 889 890 zcopy_used = len >= VHOST_GOODCOPY_LEN 891 && !vhost_exceeds_maxpend(net) 892 && vhost_net_tx_select_zcopy(net); 893 894 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 895 if (zcopy_used) { 896 struct ubuf_info *ubuf; 897 ubuf = nvq->ubuf_info + nvq->upend_idx; 898 899 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); 900 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; 901 ubuf->callback = vhost_zerocopy_callback; 902 ubuf->ctx = nvq->ubufs; 903 ubuf->desc = nvq->upend_idx; 904 refcount_set(&ubuf->refcnt, 1); 905 msg.msg_control = &ctl; 906 ctl.type = TUN_MSG_UBUF; 907 ctl.ptr = ubuf; 908 msg.msg_controllen = sizeof(ctl); 909 ubufs = nvq->ubufs; 910 atomic_inc(&ubufs->refcount); 911 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; 912 } else { 913 msg.msg_control = NULL; 914 ubufs = NULL; 915 } 916 total_len += len; 917 if (tx_can_batch(vq, total_len) && 918 likely(!vhost_exceeds_maxpend(net))) { 919 msg.msg_flags |= MSG_MORE; 920 } else { 921 msg.msg_flags &= ~MSG_MORE; 922 } 923 924 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 925 err = sock->ops->sendmsg(sock, &msg, len); 926 if (unlikely(err < 0)) { 927 if (zcopy_used) { 928 vhost_net_ubuf_put(ubufs); 929 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) 930 % UIO_MAXIOV; 931 } 932 vhost_discard_vq_desc(vq, 1); 933 vhost_net_enable_vq(net, vq); 934 break; 935 } 936 if (err != len) 937 pr_debug("Truncated TX packet: " 938 " len %d != %zd\n", err, len); 939 if (!zcopy_used) 940 vhost_add_used_and_signal(&net->dev, vq, head, 0); 941 else 942 vhost_zerocopy_signal_used(net, vq); 943 vhost_net_tx_packet(net); 944 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); 945 } 946 947 /* Expects to be always run from workqueue - which acts as 948 * read-size critical section for our kind of RCU. */ 949 static void handle_tx(struct vhost_net *net) 950 { 951 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 952 struct vhost_virtqueue *vq = &nvq->vq; 953 struct socket *sock; 954 955 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_TX); 956 sock = vq->private_data; 957 if (!sock) 958 goto out; 959 960 if (!vq_iotlb_prefetch(vq)) 961 goto out; 962 963 vhost_disable_notify(&net->dev, vq); 964 vhost_net_disable_vq(net, vq); 965 966 if (vhost_sock_zcopy(sock)) 967 handle_tx_zerocopy(net, sock); 968 else 969 handle_tx_copy(net, sock); 970 971 out: 972 mutex_unlock(&vq->mutex); 973 } 974 975 static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk) 976 { 977 struct sk_buff *head; 978 int len = 0; 979 unsigned long flags; 980 981 if (rvq->rx_ring) 982 return vhost_net_buf_peek(rvq); 983 984 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); 985 head = skb_peek(&sk->sk_receive_queue); 986 if (likely(head)) { 987 len = head->len; 988 if (skb_vlan_tag_present(head)) 989 len += VLAN_HLEN; 990 } 991 992 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); 993 return len; 994 } 995 996 static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, 997 bool *busyloop_intr) 998 { 999 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 1000 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX]; 1001 struct vhost_virtqueue *rvq = &rnvq->vq; 1002 struct vhost_virtqueue *tvq = &tnvq->vq; 1003 int len = peek_head_len(rnvq, sk); 1004 1005 if (!len && rvq->busyloop_timeout) { 1006 /* Flush batched heads first */ 1007 vhost_net_signal_used(rnvq); 1008 /* Both tx vq and rx socket were polled here */ 1009 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true); 1010 1011 len = peek_head_len(rnvq, sk); 1012 } 1013 1014 return len; 1015 } 1016 1017 /* This is a multi-buffer version of vhost_get_desc, that works if 1018 * vq has read descriptors only. 1019 * @vq - the relevant virtqueue 1020 * @datalen - data length we'll be reading 1021 * @iovcount - returned count of io vectors we fill 1022 * @log - vhost log 1023 * @log_num - log offset 1024 * @quota - headcount quota, 1 for big buffer 1025 * returns number of buffer heads allocated, negative on error 1026 */ 1027 static int get_rx_bufs(struct vhost_virtqueue *vq, 1028 struct vring_used_elem *heads, 1029 int datalen, 1030 unsigned *iovcount, 1031 struct vhost_log *log, 1032 unsigned *log_num, 1033 unsigned int quota) 1034 { 1035 unsigned int out, in; 1036 int seg = 0; 1037 int headcount = 0; 1038 unsigned d; 1039 int r, nlogs = 0; 1040 /* len is always initialized before use since we are always called with 1041 * datalen > 0. 1042 */ 1043 u32 uninitialized_var(len); 1044 1045 while (datalen > 0 && headcount < quota) { 1046 if (unlikely(seg >= UIO_MAXIOV)) { 1047 r = -ENOBUFS; 1048 goto err; 1049 } 1050 r = vhost_get_vq_desc(vq, vq->iov + seg, 1051 ARRAY_SIZE(vq->iov) - seg, &out, 1052 &in, log, log_num); 1053 if (unlikely(r < 0)) 1054 goto err; 1055 1056 d = r; 1057 if (d == vq->num) { 1058 r = 0; 1059 goto err; 1060 } 1061 if (unlikely(out || in <= 0)) { 1062 vq_err(vq, "unexpected descriptor format for RX: " 1063 "out %d, in %d\n", out, in); 1064 r = -EINVAL; 1065 goto err; 1066 } 1067 if (unlikely(log)) { 1068 nlogs += *log_num; 1069 log += *log_num; 1070 } 1071 heads[headcount].id = cpu_to_vhost32(vq, d); 1072 len = iov_length(vq->iov + seg, in); 1073 heads[headcount].len = cpu_to_vhost32(vq, len); 1074 datalen -= len; 1075 ++headcount; 1076 seg += in; 1077 } 1078 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); 1079 *iovcount = seg; 1080 if (unlikely(log)) 1081 *log_num = nlogs; 1082 1083 /* Detect overrun */ 1084 if (unlikely(datalen > 0)) { 1085 r = UIO_MAXIOV + 1; 1086 goto err; 1087 } 1088 return headcount; 1089 err: 1090 vhost_discard_vq_desc(vq, headcount); 1091 return r; 1092 } 1093 1094 /* Expects to be always run from workqueue - which acts as 1095 * read-size critical section for our kind of RCU. */ 1096 static void handle_rx(struct vhost_net *net) 1097 { 1098 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; 1099 struct vhost_virtqueue *vq = &nvq->vq; 1100 unsigned uninitialized_var(in), log; 1101 struct vhost_log *vq_log; 1102 struct msghdr msg = { 1103 .msg_name = NULL, 1104 .msg_namelen = 0, 1105 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 1106 .msg_controllen = 0, 1107 .msg_flags = MSG_DONTWAIT, 1108 }; 1109 struct virtio_net_hdr hdr = { 1110 .flags = 0, 1111 .gso_type = VIRTIO_NET_HDR_GSO_NONE 1112 }; 1113 size_t total_len = 0; 1114 int err, mergeable; 1115 s16 headcount; 1116 size_t vhost_hlen, sock_hlen; 1117 size_t vhost_len, sock_len; 1118 bool busyloop_intr = false; 1119 struct socket *sock; 1120 struct iov_iter fixup; 1121 __virtio16 num_buffers; 1122 int recv_pkts = 0; 1123 1124 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX); 1125 sock = vq->private_data; 1126 if (!sock) 1127 goto out; 1128 1129 if (!vq_iotlb_prefetch(vq)) 1130 goto out; 1131 1132 vhost_disable_notify(&net->dev, vq); 1133 vhost_net_disable_vq(net, vq); 1134 1135 vhost_hlen = nvq->vhost_hlen; 1136 sock_hlen = nvq->sock_hlen; 1137 1138 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ? 1139 vq->log : NULL; 1140 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); 1141 1142 do { 1143 sock_len = vhost_net_rx_peek_head_len(net, sock->sk, 1144 &busyloop_intr); 1145 if (!sock_len) 1146 break; 1147 sock_len += sock_hlen; 1148 vhost_len = sock_len + vhost_hlen; 1149 headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx, 1150 vhost_len, &in, vq_log, &log, 1151 likely(mergeable) ? UIO_MAXIOV : 1); 1152 /* On error, stop handling until the next kick. */ 1153 if (unlikely(headcount < 0)) 1154 goto out; 1155 /* OK, now we need to know about added descriptors. */ 1156 if (!headcount) { 1157 if (unlikely(busyloop_intr)) { 1158 vhost_poll_queue(&vq->poll); 1159 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 1160 /* They have slipped one in as we were 1161 * doing that: check again. */ 1162 vhost_disable_notify(&net->dev, vq); 1163 continue; 1164 } 1165 /* Nothing new? Wait for eventfd to tell us 1166 * they refilled. */ 1167 goto out; 1168 } 1169 busyloop_intr = false; 1170 if (nvq->rx_ring) 1171 msg.msg_control = vhost_net_buf_consume(&nvq->rxq); 1172 /* On overrun, truncate and discard */ 1173 if (unlikely(headcount > UIO_MAXIOV)) { 1174 iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1); 1175 err = sock->ops->recvmsg(sock, &msg, 1176 1, MSG_DONTWAIT | MSG_TRUNC); 1177 pr_debug("Discarded rx packet: len %zd\n", sock_len); 1178 continue; 1179 } 1180 /* We don't need to be notified again. */ 1181 iov_iter_init(&msg.msg_iter, READ, vq->iov, in, vhost_len); 1182 fixup = msg.msg_iter; 1183 if (unlikely((vhost_hlen))) { 1184 /* We will supply the header ourselves 1185 * TODO: support TSO. 1186 */ 1187 iov_iter_advance(&msg.msg_iter, vhost_hlen); 1188 } 1189 err = sock->ops->recvmsg(sock, &msg, 1190 sock_len, MSG_DONTWAIT | MSG_TRUNC); 1191 /* Userspace might have consumed the packet meanwhile: 1192 * it's not supposed to do this usually, but might be hard 1193 * to prevent. Discard data we got (if any) and keep going. */ 1194 if (unlikely(err != sock_len)) { 1195 pr_debug("Discarded rx packet: " 1196 " len %d, expected %zd\n", err, sock_len); 1197 vhost_discard_vq_desc(vq, headcount); 1198 continue; 1199 } 1200 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ 1201 if (unlikely(vhost_hlen)) { 1202 if (copy_to_iter(&hdr, sizeof(hdr), 1203 &fixup) != sizeof(hdr)) { 1204 vq_err(vq, "Unable to write vnet_hdr " 1205 "at addr %p\n", vq->iov->iov_base); 1206 goto out; 1207 } 1208 } else { 1209 /* Header came from socket; we'll need to patch 1210 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF 1211 */ 1212 iov_iter_advance(&fixup, sizeof(hdr)); 1213 } 1214 /* TODO: Should check and handle checksum. */ 1215 1216 num_buffers = cpu_to_vhost16(vq, headcount); 1217 if (likely(mergeable) && 1218 copy_to_iter(&num_buffers, sizeof num_buffers, 1219 &fixup) != sizeof num_buffers) { 1220 vq_err(vq, "Failed num_buffers write"); 1221 vhost_discard_vq_desc(vq, headcount); 1222 goto out; 1223 } 1224 nvq->done_idx += headcount; 1225 if (nvq->done_idx > VHOST_NET_BATCH) 1226 vhost_net_signal_used(nvq); 1227 if (unlikely(vq_log)) 1228 vhost_log_write(vq, vq_log, log, vhost_len, 1229 vq->iov, in); 1230 total_len += vhost_len; 1231 } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len))); 1232 1233 if (unlikely(busyloop_intr)) 1234 vhost_poll_queue(&vq->poll); 1235 else if (!sock_len) 1236 vhost_net_enable_vq(net, vq); 1237 out: 1238 vhost_net_signal_used(nvq); 1239 mutex_unlock(&vq->mutex); 1240 } 1241 1242 static void handle_tx_kick(struct vhost_work *work) 1243 { 1244 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1245 poll.work); 1246 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1247 1248 handle_tx(net); 1249 } 1250 1251 static void handle_rx_kick(struct vhost_work *work) 1252 { 1253 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1254 poll.work); 1255 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1256 1257 handle_rx(net); 1258 } 1259 1260 static void handle_tx_net(struct vhost_work *work) 1261 { 1262 struct vhost_net *net = container_of(work, struct vhost_net, 1263 poll[VHOST_NET_VQ_TX].work); 1264 handle_tx(net); 1265 } 1266 1267 static void handle_rx_net(struct vhost_work *work) 1268 { 1269 struct vhost_net *net = container_of(work, struct vhost_net, 1270 poll[VHOST_NET_VQ_RX].work); 1271 handle_rx(net); 1272 } 1273 1274 static int vhost_net_open(struct inode *inode, struct file *f) 1275 { 1276 struct vhost_net *n; 1277 struct vhost_dev *dev; 1278 struct vhost_virtqueue **vqs; 1279 void **queue; 1280 struct xdp_buff *xdp; 1281 int i; 1282 1283 n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL); 1284 if (!n) 1285 return -ENOMEM; 1286 vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL); 1287 if (!vqs) { 1288 kvfree(n); 1289 return -ENOMEM; 1290 } 1291 1292 queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *), 1293 GFP_KERNEL); 1294 if (!queue) { 1295 kfree(vqs); 1296 kvfree(n); 1297 return -ENOMEM; 1298 } 1299 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue; 1300 1301 xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL); 1302 if (!xdp) { 1303 kfree(vqs); 1304 kvfree(n); 1305 kfree(queue); 1306 return -ENOMEM; 1307 } 1308 n->vqs[VHOST_NET_VQ_TX].xdp = xdp; 1309 1310 dev = &n->dev; 1311 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; 1312 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; 1313 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; 1314 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; 1315 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 1316 n->vqs[i].ubufs = NULL; 1317 n->vqs[i].ubuf_info = NULL; 1318 n->vqs[i].upend_idx = 0; 1319 n->vqs[i].done_idx = 0; 1320 n->vqs[i].batched_xdp = 0; 1321 n->vqs[i].vhost_hlen = 0; 1322 n->vqs[i].sock_hlen = 0; 1323 n->vqs[i].rx_ring = NULL; 1324 vhost_net_buf_init(&n->vqs[i].rxq); 1325 } 1326 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX, 1327 UIO_MAXIOV + VHOST_NET_BATCH, 1328 VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT); 1329 1330 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev); 1331 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev); 1332 1333 f->private_data = n; 1334 n->page_frag.page = NULL; 1335 n->refcnt_bias = 0; 1336 1337 return 0; 1338 } 1339 1340 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 1341 struct vhost_virtqueue *vq) 1342 { 1343 struct socket *sock; 1344 struct vhost_net_virtqueue *nvq = 1345 container_of(vq, struct vhost_net_virtqueue, vq); 1346 1347 mutex_lock(&vq->mutex); 1348 sock = vq->private_data; 1349 vhost_net_disable_vq(n, vq); 1350 vq->private_data = NULL; 1351 vhost_net_buf_unproduce(nvq); 1352 nvq->rx_ring = NULL; 1353 mutex_unlock(&vq->mutex); 1354 return sock; 1355 } 1356 1357 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 1358 struct socket **rx_sock) 1359 { 1360 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); 1361 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); 1362 } 1363 1364 static void vhost_net_flush_vq(struct vhost_net *n, int index) 1365 { 1366 vhost_poll_flush(n->poll + index); 1367 vhost_poll_flush(&n->vqs[index].vq.poll); 1368 } 1369 1370 static void vhost_net_flush(struct vhost_net *n) 1371 { 1372 vhost_net_flush_vq(n, VHOST_NET_VQ_TX); 1373 vhost_net_flush_vq(n, VHOST_NET_VQ_RX); 1374 if (n->vqs[VHOST_NET_VQ_TX].ubufs) { 1375 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1376 n->tx_flush = true; 1377 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1378 /* Wait for all lower device DMAs done. */ 1379 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); 1380 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1381 n->tx_flush = false; 1382 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); 1383 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1384 } 1385 } 1386 1387 static int vhost_net_release(struct inode *inode, struct file *f) 1388 { 1389 struct vhost_net *n = f->private_data; 1390 struct socket *tx_sock; 1391 struct socket *rx_sock; 1392 1393 vhost_net_stop(n, &tx_sock, &rx_sock); 1394 vhost_net_flush(n); 1395 vhost_dev_stop(&n->dev); 1396 vhost_dev_cleanup(&n->dev); 1397 vhost_net_vq_reset(n); 1398 if (tx_sock) 1399 sockfd_put(tx_sock); 1400 if (rx_sock) 1401 sockfd_put(rx_sock); 1402 /* Make sure no callbacks are outstanding */ 1403 synchronize_rcu(); 1404 /* We do an extra flush before freeing memory, 1405 * since jobs can re-queue themselves. */ 1406 vhost_net_flush(n); 1407 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue); 1408 kfree(n->vqs[VHOST_NET_VQ_TX].xdp); 1409 kfree(n->dev.vqs); 1410 if (n->page_frag.page) 1411 __page_frag_cache_drain(n->page_frag.page, n->refcnt_bias); 1412 kvfree(n); 1413 return 0; 1414 } 1415 1416 static struct socket *get_raw_socket(int fd) 1417 { 1418 struct { 1419 struct sockaddr_ll sa; 1420 char buf[MAX_ADDR_LEN]; 1421 } uaddr; 1422 int r; 1423 struct socket *sock = sockfd_lookup(fd, &r); 1424 1425 if (!sock) 1426 return ERR_PTR(-ENOTSOCK); 1427 1428 /* Parameter checking */ 1429 if (sock->sk->sk_type != SOCK_RAW) { 1430 r = -ESOCKTNOSUPPORT; 1431 goto err; 1432 } 1433 1434 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 0); 1435 if (r < 0) 1436 goto err; 1437 1438 if (uaddr.sa.sll_family != AF_PACKET) { 1439 r = -EPFNOSUPPORT; 1440 goto err; 1441 } 1442 return sock; 1443 err: 1444 sockfd_put(sock); 1445 return ERR_PTR(r); 1446 } 1447 1448 static struct ptr_ring *get_tap_ptr_ring(int fd) 1449 { 1450 struct ptr_ring *ring; 1451 struct file *file = fget(fd); 1452 1453 if (!file) 1454 return NULL; 1455 ring = tun_get_tx_ring(file); 1456 if (!IS_ERR(ring)) 1457 goto out; 1458 ring = tap_get_ptr_ring(file); 1459 if (!IS_ERR(ring)) 1460 goto out; 1461 ring = NULL; 1462 out: 1463 fput(file); 1464 return ring; 1465 } 1466 1467 static struct socket *get_tap_socket(int fd) 1468 { 1469 struct file *file = fget(fd); 1470 struct socket *sock; 1471 1472 if (!file) 1473 return ERR_PTR(-EBADF); 1474 sock = tun_get_socket(file); 1475 if (!IS_ERR(sock)) 1476 return sock; 1477 sock = tap_get_socket(file); 1478 if (IS_ERR(sock)) 1479 fput(file); 1480 return sock; 1481 } 1482 1483 static struct socket *get_socket(int fd) 1484 { 1485 struct socket *sock; 1486 1487 /* special case to disable backend */ 1488 if (fd == -1) 1489 return NULL; 1490 sock = get_raw_socket(fd); 1491 if (!IS_ERR(sock)) 1492 return sock; 1493 sock = get_tap_socket(fd); 1494 if (!IS_ERR(sock)) 1495 return sock; 1496 return ERR_PTR(-ENOTSOCK); 1497 } 1498 1499 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 1500 { 1501 struct socket *sock, *oldsock; 1502 struct vhost_virtqueue *vq; 1503 struct vhost_net_virtqueue *nvq; 1504 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; 1505 int r; 1506 1507 mutex_lock(&n->dev.mutex); 1508 r = vhost_dev_check_owner(&n->dev); 1509 if (r) 1510 goto err; 1511 1512 if (index >= VHOST_NET_VQ_MAX) { 1513 r = -ENOBUFS; 1514 goto err; 1515 } 1516 vq = &n->vqs[index].vq; 1517 nvq = &n->vqs[index]; 1518 mutex_lock(&vq->mutex); 1519 1520 /* Verify that ring has been setup correctly. */ 1521 if (!vhost_vq_access_ok(vq)) { 1522 r = -EFAULT; 1523 goto err_vq; 1524 } 1525 sock = get_socket(fd); 1526 if (IS_ERR(sock)) { 1527 r = PTR_ERR(sock); 1528 goto err_vq; 1529 } 1530 1531 /* start polling new socket */ 1532 oldsock = vq->private_data; 1533 if (sock != oldsock) { 1534 ubufs = vhost_net_ubuf_alloc(vq, 1535 sock && vhost_sock_zcopy(sock)); 1536 if (IS_ERR(ubufs)) { 1537 r = PTR_ERR(ubufs); 1538 goto err_ubufs; 1539 } 1540 1541 vhost_net_disable_vq(n, vq); 1542 vq->private_data = sock; 1543 vhost_net_buf_unproduce(nvq); 1544 r = vhost_vq_init_access(vq); 1545 if (r) 1546 goto err_used; 1547 r = vhost_net_enable_vq(n, vq); 1548 if (r) 1549 goto err_used; 1550 if (index == VHOST_NET_VQ_RX) 1551 nvq->rx_ring = get_tap_ptr_ring(fd); 1552 1553 oldubufs = nvq->ubufs; 1554 nvq->ubufs = ubufs; 1555 1556 n->tx_packets = 0; 1557 n->tx_zcopy_err = 0; 1558 n->tx_flush = false; 1559 } 1560 1561 mutex_unlock(&vq->mutex); 1562 1563 if (oldubufs) { 1564 vhost_net_ubuf_put_wait_and_free(oldubufs); 1565 mutex_lock(&vq->mutex); 1566 vhost_zerocopy_signal_used(n, vq); 1567 mutex_unlock(&vq->mutex); 1568 } 1569 1570 if (oldsock) { 1571 vhost_net_flush_vq(n, index); 1572 sockfd_put(oldsock); 1573 } 1574 1575 mutex_unlock(&n->dev.mutex); 1576 return 0; 1577 1578 err_used: 1579 vq->private_data = oldsock; 1580 vhost_net_enable_vq(n, vq); 1581 if (ubufs) 1582 vhost_net_ubuf_put_wait_and_free(ubufs); 1583 err_ubufs: 1584 if (sock) 1585 sockfd_put(sock); 1586 err_vq: 1587 mutex_unlock(&vq->mutex); 1588 err: 1589 mutex_unlock(&n->dev.mutex); 1590 return r; 1591 } 1592 1593 static long vhost_net_reset_owner(struct vhost_net *n) 1594 { 1595 struct socket *tx_sock = NULL; 1596 struct socket *rx_sock = NULL; 1597 long err; 1598 struct vhost_umem *umem; 1599 1600 mutex_lock(&n->dev.mutex); 1601 err = vhost_dev_check_owner(&n->dev); 1602 if (err) 1603 goto done; 1604 umem = vhost_dev_reset_owner_prepare(); 1605 if (!umem) { 1606 err = -ENOMEM; 1607 goto done; 1608 } 1609 vhost_net_stop(n, &tx_sock, &rx_sock); 1610 vhost_net_flush(n); 1611 vhost_dev_stop(&n->dev); 1612 vhost_dev_reset_owner(&n->dev, umem); 1613 vhost_net_vq_reset(n); 1614 done: 1615 mutex_unlock(&n->dev.mutex); 1616 if (tx_sock) 1617 sockfd_put(tx_sock); 1618 if (rx_sock) 1619 sockfd_put(rx_sock); 1620 return err; 1621 } 1622 1623 static int vhost_net_set_backend_features(struct vhost_net *n, u64 features) 1624 { 1625 int i; 1626 1627 mutex_lock(&n->dev.mutex); 1628 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1629 mutex_lock(&n->vqs[i].vq.mutex); 1630 n->vqs[i].vq.acked_backend_features = features; 1631 mutex_unlock(&n->vqs[i].vq.mutex); 1632 } 1633 mutex_unlock(&n->dev.mutex); 1634 1635 return 0; 1636 } 1637 1638 static int vhost_net_set_features(struct vhost_net *n, u64 features) 1639 { 1640 size_t vhost_hlen, sock_hlen, hdr_len; 1641 int i; 1642 1643 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | 1644 (1ULL << VIRTIO_F_VERSION_1))) ? 1645 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 1646 sizeof(struct virtio_net_hdr); 1647 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 1648 /* vhost provides vnet_hdr */ 1649 vhost_hlen = hdr_len; 1650 sock_hlen = 0; 1651 } else { 1652 /* socket provides vnet_hdr */ 1653 vhost_hlen = 0; 1654 sock_hlen = hdr_len; 1655 } 1656 mutex_lock(&n->dev.mutex); 1657 if ((features & (1 << VHOST_F_LOG_ALL)) && 1658 !vhost_log_access_ok(&n->dev)) 1659 goto out_unlock; 1660 1661 if ((features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))) { 1662 if (vhost_init_device_iotlb(&n->dev, true)) 1663 goto out_unlock; 1664 } 1665 1666 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1667 mutex_lock(&n->vqs[i].vq.mutex); 1668 n->vqs[i].vq.acked_features = features; 1669 n->vqs[i].vhost_hlen = vhost_hlen; 1670 n->vqs[i].sock_hlen = sock_hlen; 1671 mutex_unlock(&n->vqs[i].vq.mutex); 1672 } 1673 mutex_unlock(&n->dev.mutex); 1674 return 0; 1675 1676 out_unlock: 1677 mutex_unlock(&n->dev.mutex); 1678 return -EFAULT; 1679 } 1680 1681 static long vhost_net_set_owner(struct vhost_net *n) 1682 { 1683 int r; 1684 1685 mutex_lock(&n->dev.mutex); 1686 if (vhost_dev_has_owner(&n->dev)) { 1687 r = -EBUSY; 1688 goto out; 1689 } 1690 r = vhost_net_set_ubuf_info(n); 1691 if (r) 1692 goto out; 1693 r = vhost_dev_set_owner(&n->dev); 1694 if (r) 1695 vhost_net_clear_ubuf_info(n); 1696 vhost_net_flush(n); 1697 out: 1698 mutex_unlock(&n->dev.mutex); 1699 return r; 1700 } 1701 1702 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 1703 unsigned long arg) 1704 { 1705 struct vhost_net *n = f->private_data; 1706 void __user *argp = (void __user *)arg; 1707 u64 __user *featurep = argp; 1708 struct vhost_vring_file backend; 1709 u64 features; 1710 int r; 1711 1712 switch (ioctl) { 1713 case VHOST_NET_SET_BACKEND: 1714 if (copy_from_user(&backend, argp, sizeof backend)) 1715 return -EFAULT; 1716 return vhost_net_set_backend(n, backend.index, backend.fd); 1717 case VHOST_GET_FEATURES: 1718 features = VHOST_NET_FEATURES; 1719 if (copy_to_user(featurep, &features, sizeof features)) 1720 return -EFAULT; 1721 return 0; 1722 case VHOST_SET_FEATURES: 1723 if (copy_from_user(&features, featurep, sizeof features)) 1724 return -EFAULT; 1725 if (features & ~VHOST_NET_FEATURES) 1726 return -EOPNOTSUPP; 1727 return vhost_net_set_features(n, features); 1728 case VHOST_GET_BACKEND_FEATURES: 1729 features = VHOST_NET_BACKEND_FEATURES; 1730 if (copy_to_user(featurep, &features, sizeof(features))) 1731 return -EFAULT; 1732 return 0; 1733 case VHOST_SET_BACKEND_FEATURES: 1734 if (copy_from_user(&features, featurep, sizeof(features))) 1735 return -EFAULT; 1736 if (features & ~VHOST_NET_BACKEND_FEATURES) 1737 return -EOPNOTSUPP; 1738 return vhost_net_set_backend_features(n, features); 1739 case VHOST_RESET_OWNER: 1740 return vhost_net_reset_owner(n); 1741 case VHOST_SET_OWNER: 1742 return vhost_net_set_owner(n); 1743 default: 1744 mutex_lock(&n->dev.mutex); 1745 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 1746 if (r == -ENOIOCTLCMD) 1747 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 1748 else 1749 vhost_net_flush(n); 1750 mutex_unlock(&n->dev.mutex); 1751 return r; 1752 } 1753 } 1754 1755 #ifdef CONFIG_COMPAT 1756 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, 1757 unsigned long arg) 1758 { 1759 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); 1760 } 1761 #endif 1762 1763 static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1764 { 1765 struct file *file = iocb->ki_filp; 1766 struct vhost_net *n = file->private_data; 1767 struct vhost_dev *dev = &n->dev; 1768 int noblock = file->f_flags & O_NONBLOCK; 1769 1770 return vhost_chr_read_iter(dev, to, noblock); 1771 } 1772 1773 static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb, 1774 struct iov_iter *from) 1775 { 1776 struct file *file = iocb->ki_filp; 1777 struct vhost_net *n = file->private_data; 1778 struct vhost_dev *dev = &n->dev; 1779 1780 return vhost_chr_write_iter(dev, from); 1781 } 1782 1783 static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait) 1784 { 1785 struct vhost_net *n = file->private_data; 1786 struct vhost_dev *dev = &n->dev; 1787 1788 return vhost_chr_poll(file, dev, wait); 1789 } 1790 1791 static const struct file_operations vhost_net_fops = { 1792 .owner = THIS_MODULE, 1793 .release = vhost_net_release, 1794 .read_iter = vhost_net_chr_read_iter, 1795 .write_iter = vhost_net_chr_write_iter, 1796 .poll = vhost_net_chr_poll, 1797 .unlocked_ioctl = vhost_net_ioctl, 1798 #ifdef CONFIG_COMPAT 1799 .compat_ioctl = vhost_net_compat_ioctl, 1800 #endif 1801 .open = vhost_net_open, 1802 .llseek = noop_llseek, 1803 }; 1804 1805 static struct miscdevice vhost_net_misc = { 1806 .minor = VHOST_NET_MINOR, 1807 .name = "vhost-net", 1808 .fops = &vhost_net_fops, 1809 }; 1810 1811 static int vhost_net_init(void) 1812 { 1813 if (experimental_zcopytx) 1814 vhost_net_enable_zcopy(VHOST_NET_VQ_TX); 1815 return misc_register(&vhost_net_misc); 1816 } 1817 module_init(vhost_net_init); 1818 1819 static void vhost_net_exit(void) 1820 { 1821 misc_deregister(&vhost_net_misc); 1822 } 1823 module_exit(vhost_net_exit); 1824 1825 MODULE_VERSION("0.0.1"); 1826 MODULE_LICENSE("GPL v2"); 1827 MODULE_AUTHOR("Michael S. Tsirkin"); 1828 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1829 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1830 MODULE_ALIAS("devname:vhost-net"); 1831