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 38static int experimental_zcopytx = 0; 39module_param(experimental_zcopytx, int, 0444); 40MODULE_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 72enum { 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}; 78 79enum { 80 VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) 81}; 82 83enum { 84 VHOST_NET_VQ_RX = 0, 85 VHOST_NET_VQ_TX = 1, 86 VHOST_NET_VQ_MAX = 2, 87}; 88 89struct vhost_net_ubuf_ref { 90 /* refcount follows semantics similar to kref: 91 * 0: object is released 92 * 1: no outstanding ubufs 93 * >1: outstanding ubufs 94 */ 95 atomic_t refcount; 96 wait_queue_head_t wait; 97 struct vhost_virtqueue *vq; 98}; 99 100#define VHOST_NET_BATCH 64 101struct vhost_net_buf { 102 void **queue; 103 int tail; 104 int head; 105}; 106 107struct vhost_net_virtqueue { 108 struct vhost_virtqueue vq; 109 size_t vhost_hlen; 110 size_t sock_hlen; 111 /* vhost zerocopy support fields below: */ 112 /* last used idx for outstanding DMA zerocopy buffers */ 113 int upend_idx; 114 /* For TX, first used idx for DMA done zerocopy buffers 115 * For RX, number of batched heads 116 */ 117 int done_idx; 118 /* Number of XDP frames batched */ 119 int batched_xdp; 120 /* an array of userspace buffers info */ 121 struct ubuf_info *ubuf_info; 122 /* Reference counting for outstanding ubufs. 123 * Protected by vq mutex. Writers must also take device mutex. */ 124 struct vhost_net_ubuf_ref *ubufs; 125 struct ptr_ring *rx_ring; 126 struct vhost_net_buf rxq; 127 /* Batched XDP buffs */ 128 struct xdp_buff *xdp; 129}; 130 131struct vhost_net { 132 struct vhost_dev dev; 133 struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX]; 134 struct vhost_poll poll[VHOST_NET_VQ_MAX]; 135 /* Number of TX recently submitted. 136 * Protected by tx vq lock. */ 137 unsigned tx_packets; 138 /* Number of times zerocopy TX recently failed. 139 * Protected by tx vq lock. */ 140 unsigned tx_zcopy_err; 141 /* Flush in progress. Protected by tx vq lock. */ 142 bool tx_flush; 143 /* Private page frag */ 144 struct page_frag page_frag; 145 /* Refcount bias of page frag */ 146 int refcnt_bias; 147}; 148 149static unsigned vhost_net_zcopy_mask __read_mostly; 150 151static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq) 152{ 153 if (rxq->tail != rxq->head) 154 return rxq->queue[rxq->head]; 155 else 156 return NULL; 157} 158 159static int vhost_net_buf_get_size(struct vhost_net_buf *rxq) 160{ 161 return rxq->tail - rxq->head; 162} 163 164static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq) 165{ 166 return rxq->tail == rxq->head; 167} 168 169static void *vhost_net_buf_consume(struct vhost_net_buf *rxq) 170{ 171 void *ret = vhost_net_buf_get_ptr(rxq); 172 ++rxq->head; 173 return ret; 174} 175 176static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq) 177{ 178 struct vhost_net_buf *rxq = &nvq->rxq; 179 180 rxq->head = 0; 181 rxq->tail = ptr_ring_consume_batched(nvq->rx_ring, rxq->queue, 182 VHOST_NET_BATCH); 183 return rxq->tail; 184} 185 186static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq) 187{ 188 struct vhost_net_buf *rxq = &nvq->rxq; 189 190 if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) { 191 ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head, 192 vhost_net_buf_get_size(rxq), 193 tun_ptr_free); 194 rxq->head = rxq->tail = 0; 195 } 196} 197 198static int vhost_net_buf_peek_len(void *ptr) 199{ 200 if (tun_is_xdp_frame(ptr)) { 201 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr); 202 203 return xdpf->len; 204 } 205 206 return __skb_array_len_with_tag(ptr); 207} 208 209static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq) 210{ 211 struct vhost_net_buf *rxq = &nvq->rxq; 212 213 if (!vhost_net_buf_is_empty(rxq)) 214 goto out; 215 216 if (!vhost_net_buf_produce(nvq)) 217 return 0; 218 219out: 220 return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq)); 221} 222 223static void vhost_net_buf_init(struct vhost_net_buf *rxq) 224{ 225 rxq->head = rxq->tail = 0; 226} 227 228static void vhost_net_enable_zcopy(int vq) 229{ 230 vhost_net_zcopy_mask |= 0x1 << vq; 231} 232 233static struct vhost_net_ubuf_ref * 234vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy) 235{ 236 struct vhost_net_ubuf_ref *ubufs; 237 /* No zero copy backend? Nothing to count. */ 238 if (!zcopy) 239 return NULL; 240 ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL); 241 if (!ubufs) 242 return ERR_PTR(-ENOMEM); 243 atomic_set(&ubufs->refcount, 1); 244 init_waitqueue_head(&ubufs->wait); 245 ubufs->vq = vq; 246 return ubufs; 247} 248 249static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs) 250{ 251 int r = atomic_sub_return(1, &ubufs->refcount); 252 if (unlikely(!r)) 253 wake_up(&ubufs->wait); 254 return r; 255} 256 257static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) 258{ 259 vhost_net_ubuf_put(ubufs); 260 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); 261} 262 263static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) 264{ 265 vhost_net_ubuf_put_and_wait(ubufs); 266 kfree(ubufs); 267} 268 269static void vhost_net_clear_ubuf_info(struct vhost_net *n) 270{ 271 int i; 272 273 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 274 kfree(n->vqs[i].ubuf_info); 275 n->vqs[i].ubuf_info = NULL; 276 } 277} 278 279static int vhost_net_set_ubuf_info(struct vhost_net *n) 280{ 281 bool zcopy; 282 int i; 283 284 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 285 zcopy = vhost_net_zcopy_mask & (0x1 << i); 286 if (!zcopy) 287 continue; 288 n->vqs[i].ubuf_info = 289 kmalloc_array(UIO_MAXIOV, 290 sizeof(*n->vqs[i].ubuf_info), 291 GFP_KERNEL); 292 if (!n->vqs[i].ubuf_info) 293 goto err; 294 } 295 return 0; 296 297err: 298 vhost_net_clear_ubuf_info(n); 299 return -ENOMEM; 300} 301 302static void vhost_net_vq_reset(struct vhost_net *n) 303{ 304 int i; 305 306 vhost_net_clear_ubuf_info(n); 307 308 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 309 n->vqs[i].done_idx = 0; 310 n->vqs[i].upend_idx = 0; 311 n->vqs[i].ubufs = NULL; 312 n->vqs[i].vhost_hlen = 0; 313 n->vqs[i].sock_hlen = 0; 314 vhost_net_buf_init(&n->vqs[i].rxq); 315 } 316 317} 318 319static void vhost_net_tx_packet(struct vhost_net *net) 320{ 321 ++net->tx_packets; 322 if (net->tx_packets < 1024) 323 return; 324 net->tx_packets = 0; 325 net->tx_zcopy_err = 0; 326} 327 328static void vhost_net_tx_err(struct vhost_net *net) 329{ 330 ++net->tx_zcopy_err; 331} 332 333static bool vhost_net_tx_select_zcopy(struct vhost_net *net) 334{ 335 /* TX flush waits for outstanding DMAs to be done. 336 * Don't start new DMAs. 337 */ 338 return !net->tx_flush && 339 net->tx_packets / 64 >= net->tx_zcopy_err; 340} 341 342static bool vhost_sock_zcopy(struct socket *sock) 343{ 344 return unlikely(experimental_zcopytx) && 345 sock_flag(sock->sk, SOCK_ZEROCOPY); 346} 347 348static bool vhost_sock_xdp(struct socket *sock) 349{ 350 return sock_flag(sock->sk, SOCK_XDP); 351} 352 353/* In case of DMA done not in order in lower device driver for some reason. 354 * upend_idx is used to track end of used idx, done_idx is used to track head 355 * of used idx. Once lower device DMA done contiguously, we will signal KVM 356 * guest used idx. 357 */ 358static void vhost_zerocopy_signal_used(struct vhost_net *net, 359 struct vhost_virtqueue *vq) 360{ 361 struct vhost_net_virtqueue *nvq = 362 container_of(vq, struct vhost_net_virtqueue, vq); 363 int i, add; 364 int j = 0; 365 366 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { 367 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) 368 vhost_net_tx_err(net); 369 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { 370 vq->heads[i].len = VHOST_DMA_CLEAR_LEN; 371 ++j; 372 } else 373 break; 374 } 375 while (j) { 376 add = min(UIO_MAXIOV - nvq->done_idx, j); 377 vhost_add_used_and_signal_n(vq->dev, vq, 378 &vq->heads[nvq->done_idx], add); 379 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; 380 j -= add; 381 } 382} 383 384static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) 385{ 386 struct vhost_net_ubuf_ref *ubufs = ubuf->ctx; 387 struct vhost_virtqueue *vq = ubufs->vq; 388 int cnt; 389 390 rcu_read_lock_bh(); 391 392 /* set len to mark this desc buffers done DMA */ 393 vq->heads[ubuf->desc].len = success ? 394 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; 395 cnt = vhost_net_ubuf_put(ubufs); 396 397 /* 398 * Trigger polling thread if guest stopped submitting new buffers: 399 * in this case, the refcount after decrement will eventually reach 1. 400 * We also trigger polling periodically after each 16 packets 401 * (the value 16 here is more or less arbitrary, it's tuned to trigger 402 * less than 10% of times). 403 */ 404 if (cnt <= 1 || !(cnt % 16)) 405 vhost_poll_queue(&vq->poll); 406 407 rcu_read_unlock_bh(); 408} 409 410static inline unsigned long busy_clock(void) 411{ 412 return local_clock() >> 10; 413} 414 415static bool vhost_can_busy_poll(unsigned long endtime) 416{ 417 return likely(!need_resched() && !time_after(busy_clock(), endtime) && 418 !signal_pending(current)); 419} 420 421static void vhost_net_disable_vq(struct vhost_net *n, 422 struct vhost_virtqueue *vq) 423{ 424 struct vhost_net_virtqueue *nvq = 425 container_of(vq, struct vhost_net_virtqueue, vq); 426 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 427 if (!vhost_vq_get_backend(vq)) 428 return; 429 vhost_poll_stop(poll); 430} 431 432static int vhost_net_enable_vq(struct vhost_net *n, 433 struct vhost_virtqueue *vq) 434{ 435 struct vhost_net_virtqueue *nvq = 436 container_of(vq, struct vhost_net_virtqueue, vq); 437 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 438 struct socket *sock; 439 440 sock = vhost_vq_get_backend(vq); 441 if (!sock) 442 return 0; 443 444 return vhost_poll_start(poll, sock->file); 445} 446 447static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq) 448{ 449 struct vhost_virtqueue *vq = &nvq->vq; 450 struct vhost_dev *dev = vq->dev; 451 452 if (!nvq->done_idx) 453 return; 454 455 vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx); 456 nvq->done_idx = 0; 457} 458 459static void vhost_tx_batch(struct vhost_net *net, 460 struct vhost_net_virtqueue *nvq, 461 struct socket *sock, 462 struct msghdr *msghdr) 463{ 464 struct tun_msg_ctl ctl = { 465 .type = TUN_MSG_PTR, 466 .num = nvq->batched_xdp, 467 .ptr = nvq->xdp, 468 }; 469 int i, err; 470 471 if (nvq->batched_xdp == 0) 472 goto signal_used; 473 474 msghdr->msg_control = &ctl; 475 msghdr->msg_controllen = sizeof(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"); 479 480 /* free pages owned by XDP; since this is an unlikely error path, 481 * keep it simple and avoid more complex bulk update for the 482 * used pages 483 */ 484 for (i = 0; i < nvq->batched_xdp; ++i) 485 put_page(virt_to_head_page(nvq->xdp[i].data)); 486 nvq->batched_xdp = 0; 487 nvq->done_idx = 0; 488 return; 489 } 490 491signal_used: 492 vhost_net_signal_used(nvq); 493 nvq->batched_xdp = 0; 494} 495 496static int sock_has_rx_data(struct socket *sock) 497{ 498 if (unlikely(!sock)) 499 return 0; 500 501 if (sock->ops->peek_len) 502 return sock->ops->peek_len(sock); 503 504 return skb_queue_empty(&sock->sk->sk_receive_queue); 505} 506 507static void vhost_net_busy_poll_try_queue(struct vhost_net *net, 508 struct vhost_virtqueue *vq) 509{ 510 if (!vhost_vq_avail_empty(&net->dev, vq)) { 511 vhost_poll_queue(&vq->poll); 512 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 513 vhost_disable_notify(&net->dev, vq); 514 vhost_poll_queue(&vq->poll); 515 } 516} 517 518static void vhost_net_busy_poll(struct vhost_net *net, 519 struct vhost_virtqueue *rvq, 520 struct vhost_virtqueue *tvq, 521 bool *busyloop_intr, 522 bool poll_rx) 523{ 524 unsigned long busyloop_timeout; 525 unsigned long endtime; 526 struct socket *sock; 527 struct vhost_virtqueue *vq = poll_rx ? tvq : rvq; 528 529 /* Try to hold the vq mutex of the paired virtqueue. We can't 530 * use mutex_lock() here since we could not guarantee a 531 * consistenet lock ordering. 532 */ 533 if (!mutex_trylock(&vq->mutex)) 534 return; 535 536 vhost_disable_notify(&net->dev, vq); 537 sock = vhost_vq_get_backend(rvq); 538 539 busyloop_timeout = poll_rx ? rvq->busyloop_timeout: 540 tvq->busyloop_timeout; 541 542 preempt_disable(); 543 endtime = busy_clock() + busyloop_timeout; 544 545 while (vhost_can_busy_poll(endtime)) { 546 if (vhost_has_work(&net->dev)) { 547 *busyloop_intr = true; 548 break; 549 } 550 551 if ((sock_has_rx_data(sock) && 552 !vhost_vq_avail_empty(&net->dev, rvq)) || 553 !vhost_vq_avail_empty(&net->dev, tvq)) 554 break; 555 556 cpu_relax(); 557 } 558 559 preempt_enable(); 560 561 if (poll_rx || sock_has_rx_data(sock)) 562 vhost_net_busy_poll_try_queue(net, vq); 563 else if (!poll_rx) /* On tx here, sock has no rx data. */ 564 vhost_enable_notify(&net->dev, rvq); 565 566 mutex_unlock(&vq->mutex); 567} 568 569static int vhost_net_tx_get_vq_desc(struct vhost_net *net, 570 struct vhost_net_virtqueue *tnvq, 571 unsigned int *out_num, unsigned int *in_num, 572 struct msghdr *msghdr, bool *busyloop_intr) 573{ 574 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 575 struct vhost_virtqueue *rvq = &rnvq->vq; 576 struct vhost_virtqueue *tvq = &tnvq->vq; 577 578 int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), 579 out_num, in_num, NULL, NULL); 580 581 if (r == tvq->num && tvq->busyloop_timeout) { 582 /* Flush batched packets first */ 583 if (!vhost_sock_zcopy(vhost_vq_get_backend(tvq))) 584 vhost_tx_batch(net, tnvq, 585 vhost_vq_get_backend(tvq), 586 msghdr); 587 588 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false); 589 590 r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), 591 out_num, in_num, NULL, NULL); 592 } 593 594 return r; 595} 596 597static bool vhost_exceeds_maxpend(struct vhost_net *net) 598{ 599 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 600 struct vhost_virtqueue *vq = &nvq->vq; 601 602 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV > 603 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2); 604} 605 606static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter, 607 size_t hdr_size, int out) 608{ 609 /* Skip header. TODO: support TSO. */ 610 size_t len = iov_length(vq->iov, out); 611 612 iov_iter_init(iter, WRITE, vq->iov, out, len); 613 iov_iter_advance(iter, hdr_size); 614 615 return iov_iter_count(iter); 616} 617 618static int get_tx_bufs(struct vhost_net *net, 619 struct vhost_net_virtqueue *nvq, 620 struct msghdr *msg, 621 unsigned int *out, unsigned int *in, 622 size_t *len, bool *busyloop_intr) 623{ 624 struct vhost_virtqueue *vq = &nvq->vq; 625 int ret; 626 627 ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr); 628 629 if (ret < 0 || ret == vq->num) 630 return ret; 631 632 if (*in) { 633 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n", 634 *out, *in); 635 return -EFAULT; 636 } 637 638 /* Sanity check */ 639 *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out); 640 if (*len == 0) { 641 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n", 642 *len, nvq->vhost_hlen); 643 return -EFAULT; 644 } 645 646 return ret; 647} 648 649static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len) 650{ 651 return total_len < VHOST_NET_WEIGHT && 652 !vhost_vq_avail_empty(vq->dev, vq); 653} 654 655static bool vhost_net_page_frag_refill(struct vhost_net *net, unsigned int sz, 656 struct page_frag *pfrag, gfp_t gfp) 657{ 658 if (pfrag->page) { 659 if (pfrag->offset + sz <= pfrag->size) 660 return true; 661 __page_frag_cache_drain(pfrag->page, net->refcnt_bias); 662 } 663 664 pfrag->offset = 0; 665 net->refcnt_bias = 0; 666 if (SKB_FRAG_PAGE_ORDER) { 667 /* Avoid direct reclaim but allow kswapd to wake */ 668 pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) | 669 __GFP_COMP | __GFP_NOWARN | 670 __GFP_NORETRY, 671 SKB_FRAG_PAGE_ORDER); 672 if (likely(pfrag->page)) { 673 pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER; 674 goto done; 675 } 676 } 677 pfrag->page = alloc_page(gfp); 678 if (likely(pfrag->page)) { 679 pfrag->size = PAGE_SIZE; 680 goto done; 681 } 682 return false; 683 684done: 685 net->refcnt_bias = USHRT_MAX; 686 page_ref_add(pfrag->page, USHRT_MAX - 1); 687 return true; 688} 689 690#define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD) 691 692static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, 693 struct iov_iter *from) 694{ 695 struct vhost_virtqueue *vq = &nvq->vq; 696 struct vhost_net *net = container_of(vq->dev, struct vhost_net, 697 dev); 698 struct socket *sock = vhost_vq_get_backend(vq); 699 struct page_frag *alloc_frag = &net->page_frag; 700 struct virtio_net_hdr *gso; 701 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp]; 702 struct tun_xdp_hdr *hdr; 703 size_t len = iov_iter_count(from); 704 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0; 705 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 706 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen); 707 int sock_hlen = nvq->sock_hlen; 708 void *buf; 709 int copied; 710 711 if (unlikely(len < nvq->sock_hlen)) 712 return -EFAULT; 713 714 if (SKB_DATA_ALIGN(len + pad) + 715 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE) 716 return -ENOSPC; 717 718 buflen += SKB_DATA_ALIGN(len + pad); 719 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES); 720 if (unlikely(!vhost_net_page_frag_refill(net, buflen, 721 alloc_frag, GFP_KERNEL))) 722 return -ENOMEM; 723 724 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset; 725 copied = copy_page_from_iter(alloc_frag->page, 726 alloc_frag->offset + 727 offsetof(struct tun_xdp_hdr, gso), 728 sock_hlen, from); 729 if (copied != sock_hlen) 730 return -EFAULT; 731 732 hdr = buf; 733 gso = &hdr->gso; 734 735 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 736 vhost16_to_cpu(vq, gso->csum_start) + 737 vhost16_to_cpu(vq, gso->csum_offset) + 2 > 738 vhost16_to_cpu(vq, gso->hdr_len)) { 739 gso->hdr_len = cpu_to_vhost16(vq, 740 vhost16_to_cpu(vq, gso->csum_start) + 741 vhost16_to_cpu(vq, gso->csum_offset) + 2); 742 743 if (vhost16_to_cpu(vq, gso->hdr_len) > len) 744 return -EINVAL; 745 } 746 747 len -= sock_hlen; 748 copied = copy_page_from_iter(alloc_frag->page, 749 alloc_frag->offset + pad, 750 len, from); 751 if (copied != len) 752 return -EFAULT; 753 754 xdp->data_hard_start = buf; 755 xdp->data = buf + pad; 756 xdp->data_end = xdp->data + len; 757 hdr->buflen = buflen; 758 xdp->frame_sz = buflen; 759 760 --net->refcnt_bias; 761 alloc_frag->offset += buflen; 762 763 ++nvq->batched_xdp; 764 765 return 0; 766} 767 768static void handle_tx_copy(struct vhost_net *net, struct socket *sock) 769{ 770 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 771 struct vhost_virtqueue *vq = &nvq->vq; 772 unsigned out, in; 773 int head; 774 struct msghdr msg = { 775 .msg_name = NULL, 776 .msg_namelen = 0, 777 .msg_control = NULL, 778 .msg_controllen = 0, 779 .msg_flags = MSG_DONTWAIT, 780 }; 781 size_t len, total_len = 0; 782 int err; 783 int sent_pkts = 0; 784 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX); 785 786 do { 787 bool busyloop_intr = false; 788 789 if (nvq->done_idx == VHOST_NET_BATCH) 790 vhost_tx_batch(net, nvq, sock, &msg); 791 792 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 793 &busyloop_intr); 794 /* On error, stop handling until the next kick. */ 795 if (unlikely(head < 0)) 796 break; 797 /* Nothing new? Wait for eventfd to tell us they refilled. */ 798 if (head == vq->num) { 799 if (unlikely(busyloop_intr)) { 800 vhost_poll_queue(&vq->poll); 801 } else if (unlikely(vhost_enable_notify(&net->dev, 802 vq))) { 803 vhost_disable_notify(&net->dev, vq); 804 continue; 805 } 806 break; 807 } 808 809 total_len += len; 810 811 /* For simplicity, TX batching is only enabled if 812 * sndbuf is unlimited. 813 */ 814 if (sock_can_batch) { 815 err = vhost_net_build_xdp(nvq, &msg.msg_iter); 816 if (!err) { 817 goto done; 818 } else if (unlikely(err != -ENOSPC)) { 819 vhost_tx_batch(net, nvq, sock, &msg); 820 vhost_discard_vq_desc(vq, 1); 821 vhost_net_enable_vq(net, vq); 822 break; 823 } 824 825 /* We can't build XDP buff, go for single 826 * packet path but let's flush batched 827 * packets. 828 */ 829 vhost_tx_batch(net, nvq, sock, &msg); 830 msg.msg_control = NULL; 831 } else { 832 if (tx_can_batch(vq, total_len)) 833 msg.msg_flags |= MSG_MORE; 834 else 835 msg.msg_flags &= ~MSG_MORE; 836 } 837 838 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 839 err = sock->ops->sendmsg(sock, &msg, len); 840 if (unlikely(err < 0)) { 841 vhost_discard_vq_desc(vq, 1); 842 vhost_net_enable_vq(net, vq); 843 break; 844 } 845 if (err != len) 846 pr_debug("Truncated TX packet: len %d != %zd\n", 847 err, len); 848done: 849 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head); 850 vq->heads[nvq->done_idx].len = 0; 851 ++nvq->done_idx; 852 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); 853 854 vhost_tx_batch(net, nvq, sock, &msg); 855} 856 857static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) 858{ 859 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 860 struct vhost_virtqueue *vq = &nvq->vq; 861 unsigned out, in; 862 int head; 863 struct msghdr msg = { 864 .msg_name = NULL, 865 .msg_namelen = 0, 866 .msg_control = NULL, 867 .msg_controllen = 0, 868 .msg_flags = MSG_DONTWAIT, 869 }; 870 struct tun_msg_ctl ctl; 871 size_t len, total_len = 0; 872 int err; 873 struct vhost_net_ubuf_ref *ubufs; 874 struct ubuf_info *ubuf; 875 bool zcopy_used; 876 int sent_pkts = 0; 877 878 do { 879 bool busyloop_intr; 880 881 /* Release DMAs done buffers first */ 882 vhost_zerocopy_signal_used(net, vq); 883 884 busyloop_intr = false; 885 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 886 &busyloop_intr); 887 /* On error, stop handling until the next kick. */ 888 if (unlikely(head < 0)) 889 break; 890 /* Nothing new? Wait for eventfd to tell us they refilled. */ 891 if (head == vq->num) { 892 if (unlikely(busyloop_intr)) { 893 vhost_poll_queue(&vq->poll); 894 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 895 vhost_disable_notify(&net->dev, vq); 896 continue; 897 } 898 break; 899 } 900 901 zcopy_used = len >= VHOST_GOODCOPY_LEN 902 && !vhost_exceeds_maxpend(net) 903 && vhost_net_tx_select_zcopy(net); 904 905 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 906 if (zcopy_used) { 907 ubuf = nvq->ubuf_info + nvq->upend_idx; 908 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); 909 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; 910 ubuf->callback = vhost_zerocopy_callback; 911 ubuf->ctx = nvq->ubufs; 912 ubuf->desc = nvq->upend_idx; 913 refcount_set(&ubuf->refcnt, 1); 914 msg.msg_control = &ctl; 915 ctl.type = TUN_MSG_UBUF; 916 ctl.ptr = ubuf; 917 msg.msg_controllen = sizeof(ctl); 918 ubufs = nvq->ubufs; 919 atomic_inc(&ubufs->refcount); 920 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; 921 } else { 922 msg.msg_control = NULL; 923 ubufs = NULL; 924 } 925 total_len += len; 926 if (tx_can_batch(vq, total_len) && 927 likely(!vhost_exceeds_maxpend(net))) { 928 msg.msg_flags |= MSG_MORE; 929 } else { 930 msg.msg_flags &= ~MSG_MORE; 931 } 932 933 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 934 err = sock->ops->sendmsg(sock, &msg, len); 935 if (unlikely(err < 0)) { 936 if (zcopy_used) { 937 if (vq->heads[ubuf->desc].len == VHOST_DMA_IN_PROGRESS) 938 vhost_net_ubuf_put(ubufs); 939 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) 940 % UIO_MAXIOV; 941 } 942 vhost_discard_vq_desc(vq, 1); 943 vhost_net_enable_vq(net, vq); 944 break; 945 } 946 if (err != len) 947 pr_debug("Truncated TX packet: " 948 " len %d != %zd\n", err, len); 949 if (!zcopy_used) 950 vhost_add_used_and_signal(&net->dev, vq, head, 0); 951 else 952 vhost_zerocopy_signal_used(net, vq); 953 vhost_net_tx_packet(net); 954 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); 955} 956 957/* Expects to be always run from workqueue - which acts as 958 * read-size critical section for our kind of RCU. */ 959static void handle_tx(struct vhost_net *net) 960{ 961 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 962 struct vhost_virtqueue *vq = &nvq->vq; 963 struct socket *sock; 964 965 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_TX); 966 sock = vhost_vq_get_backend(vq); 967 if (!sock) 968 goto out; 969 970 if (!vq_meta_prefetch(vq)) 971 goto out; 972 973 vhost_disable_notify(&net->dev, vq); 974 vhost_net_disable_vq(net, vq); 975 976 if (vhost_sock_zcopy(sock)) 977 handle_tx_zerocopy(net, sock); 978 else 979 handle_tx_copy(net, sock); 980 981out: 982 mutex_unlock(&vq->mutex); 983} 984 985static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk) 986{ 987 struct sk_buff *head; 988 int len = 0; 989 unsigned long flags; 990 991 if (rvq->rx_ring) 992 return vhost_net_buf_peek(rvq); 993 994 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); 995 head = skb_peek(&sk->sk_receive_queue); 996 if (likely(head)) { 997 len = head->len; 998 if (skb_vlan_tag_present(head)) 999 len += VLAN_HLEN; 1000 } 1001 1002 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); 1003 return len; 1004} 1005 1006static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, 1007 bool *busyloop_intr) 1008{ 1009 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 1010 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX]; 1011 struct vhost_virtqueue *rvq = &rnvq->vq; 1012 struct vhost_virtqueue *tvq = &tnvq->vq; 1013 int len = peek_head_len(rnvq, sk); 1014 1015 if (!len && rvq->busyloop_timeout) { 1016 /* Flush batched heads first */ 1017 vhost_net_signal_used(rnvq); 1018 /* Both tx vq and rx socket were polled here */ 1019 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true); 1020 1021 len = peek_head_len(rnvq, sk); 1022 } 1023 1024 return len; 1025} 1026 1027/* This is a multi-buffer version of vhost_get_desc, that works if 1028 * vq has read descriptors only. 1029 * @vq - the relevant virtqueue 1030 * @datalen - data length we'll be reading 1031 * @iovcount - returned count of io vectors we fill 1032 * @log - vhost log 1033 * @log_num - log offset 1034 * @quota - headcount quota, 1 for big buffer 1035 * returns number of buffer heads allocated, negative on error 1036 */ 1037static int get_rx_bufs(struct vhost_virtqueue *vq, 1038 struct vring_used_elem *heads, 1039 int datalen, 1040 unsigned *iovcount, 1041 struct vhost_log *log, 1042 unsigned *log_num, 1043 unsigned int quota) 1044{ 1045 unsigned int out, in; 1046 int seg = 0; 1047 int headcount = 0; 1048 unsigned d; 1049 int r, nlogs = 0; 1050 /* len is always initialized before use since we are always called with 1051 * datalen > 0. 1052 */ 1053 u32 len; 1054 1055 while (datalen > 0 && headcount < quota) { 1056 if (unlikely(seg >= UIO_MAXIOV)) { 1057 r = -ENOBUFS; 1058 goto err; 1059 } 1060 r = vhost_get_vq_desc(vq, vq->iov + seg, 1061 ARRAY_SIZE(vq->iov) - seg, &out, 1062 &in, log, log_num); 1063 if (unlikely(r < 0)) 1064 goto err; 1065 1066 d = r; 1067 if (d == vq->num) { 1068 r = 0; 1069 goto err; 1070 } 1071 if (unlikely(out || in <= 0)) { 1072 vq_err(vq, "unexpected descriptor format for RX: " 1073 "out %d, in %d\n", out, in); 1074 r = -EINVAL; 1075 goto err; 1076 } 1077 if (unlikely(log)) { 1078 nlogs += *log_num; 1079 log += *log_num; 1080 } 1081 heads[headcount].id = cpu_to_vhost32(vq, d); 1082 len = iov_length(vq->iov + seg, in); 1083 heads[headcount].len = cpu_to_vhost32(vq, len); 1084 datalen -= len; 1085 ++headcount; 1086 seg += in; 1087 } 1088 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); 1089 *iovcount = seg; 1090 if (unlikely(log)) 1091 *log_num = nlogs; 1092 1093 /* Detect overrun */ 1094 if (unlikely(datalen > 0)) { 1095 r = UIO_MAXIOV + 1; 1096 goto err; 1097 } 1098 return headcount; 1099err: 1100 vhost_discard_vq_desc(vq, headcount); 1101 return r; 1102} 1103 1104/* Expects to be always run from workqueue - which acts as 1105 * read-size critical section for our kind of RCU. */ 1106static void handle_rx(struct vhost_net *net) 1107{ 1108 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; 1109 struct vhost_virtqueue *vq = &nvq->vq; 1110 unsigned in, log; 1111 struct vhost_log *vq_log; 1112 struct msghdr msg = { 1113 .msg_name = NULL, 1114 .msg_namelen = 0, 1115 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 1116 .msg_controllen = 0, 1117 .msg_flags = MSG_DONTWAIT, 1118 }; 1119 struct virtio_net_hdr hdr = { 1120 .flags = 0, 1121 .gso_type = VIRTIO_NET_HDR_GSO_NONE 1122 }; 1123 size_t total_len = 0; 1124 int err, mergeable; 1125 s16 headcount; 1126 size_t vhost_hlen, sock_hlen; 1127 size_t vhost_len, sock_len; 1128 bool busyloop_intr = false; 1129 struct socket *sock; 1130 struct iov_iter fixup; 1131 __virtio16 num_buffers; 1132 int recv_pkts = 0; 1133 1134 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX); 1135 sock = vhost_vq_get_backend(vq); 1136 if (!sock) 1137 goto out; 1138 1139 if (!vq_meta_prefetch(vq)) 1140 goto out; 1141 1142 vhost_disable_notify(&net->dev, vq); 1143 vhost_net_disable_vq(net, vq); 1144 1145 vhost_hlen = nvq->vhost_hlen; 1146 sock_hlen = nvq->sock_hlen; 1147 1148 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ? 1149 vq->log : NULL; 1150 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); 1151 1152 do { 1153 sock_len = vhost_net_rx_peek_head_len(net, sock->sk, 1154 &busyloop_intr); 1155 if (!sock_len) 1156 break; 1157 sock_len += sock_hlen; 1158 vhost_len = sock_len + vhost_hlen; 1159 headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx, 1160 vhost_len, &in, vq_log, &log, 1161 likely(mergeable) ? UIO_MAXIOV : 1); 1162 /* On error, stop handling until the next kick. */ 1163 if (unlikely(headcount < 0)) 1164 goto out; 1165 /* OK, now we need to know about added descriptors. */ 1166 if (!headcount) { 1167 if (unlikely(busyloop_intr)) { 1168 vhost_poll_queue(&vq->poll); 1169 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 1170 /* They have slipped one in as we were 1171 * doing that: check again. */ 1172 vhost_disable_notify(&net->dev, vq); 1173 continue; 1174 } 1175 /* Nothing new? Wait for eventfd to tell us 1176 * they refilled. */ 1177 goto out; 1178 } 1179 busyloop_intr = false; 1180 if (nvq->rx_ring) 1181 msg.msg_control = vhost_net_buf_consume(&nvq->rxq); 1182 /* On overrun, truncate and discard */ 1183 if (unlikely(headcount > UIO_MAXIOV)) { 1184 iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1); 1185 err = sock->ops->recvmsg(sock, &msg, 1186 1, MSG_DONTWAIT | MSG_TRUNC); 1187 pr_debug("Discarded rx packet: len %zd\n", sock_len); 1188 continue; 1189 } 1190 /* We don't need to be notified again. */ 1191 iov_iter_init(&msg.msg_iter, READ, vq->iov, in, vhost_len); 1192 fixup = msg.msg_iter; 1193 if (unlikely((vhost_hlen))) { 1194 /* We will supply the header ourselves 1195 * TODO: support TSO. 1196 */ 1197 iov_iter_advance(&msg.msg_iter, vhost_hlen); 1198 } 1199 err = sock->ops->recvmsg(sock, &msg, 1200 sock_len, MSG_DONTWAIT | MSG_TRUNC); 1201 /* Userspace might have consumed the packet meanwhile: 1202 * it's not supposed to do this usually, but might be hard 1203 * to prevent. Discard data we got (if any) and keep going. */ 1204 if (unlikely(err != sock_len)) { 1205 pr_debug("Discarded rx packet: " 1206 " len %d, expected %zd\n", err, sock_len); 1207 vhost_discard_vq_desc(vq, headcount); 1208 continue; 1209 } 1210 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ 1211 if (unlikely(vhost_hlen)) { 1212 if (copy_to_iter(&hdr, sizeof(hdr), 1213 &fixup) != sizeof(hdr)) { 1214 vq_err(vq, "Unable to write vnet_hdr " 1215 "at addr %p\n", vq->iov->iov_base); 1216 goto out; 1217 } 1218 } else { 1219 /* Header came from socket; we'll need to patch 1220 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF 1221 */ 1222 iov_iter_advance(&fixup, sizeof(hdr)); 1223 } 1224 /* TODO: Should check and handle checksum. */ 1225 1226 num_buffers = cpu_to_vhost16(vq, headcount); 1227 if (likely(mergeable) && 1228 copy_to_iter(&num_buffers, sizeof num_buffers, 1229 &fixup) != sizeof num_buffers) { 1230 vq_err(vq, "Failed num_buffers write"); 1231 vhost_discard_vq_desc(vq, headcount); 1232 goto out; 1233 } 1234 nvq->done_idx += headcount; 1235 if (nvq->done_idx > VHOST_NET_BATCH) 1236 vhost_net_signal_used(nvq); 1237 if (unlikely(vq_log)) 1238 vhost_log_write(vq, vq_log, log, vhost_len, 1239 vq->iov, in); 1240 total_len += vhost_len; 1241 } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len))); 1242 1243 if (unlikely(busyloop_intr)) 1244 vhost_poll_queue(&vq->poll); 1245 else if (!sock_len) 1246 vhost_net_enable_vq(net, vq); 1247out: 1248 vhost_net_signal_used(nvq); 1249 mutex_unlock(&vq->mutex); 1250} 1251 1252static void handle_tx_kick(struct vhost_work *work) 1253{ 1254 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1255 poll.work); 1256 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1257 1258 handle_tx(net); 1259} 1260 1261static void handle_rx_kick(struct vhost_work *work) 1262{ 1263 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1264 poll.work); 1265 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1266 1267 handle_rx(net); 1268} 1269 1270static void handle_tx_net(struct vhost_work *work) 1271{ 1272 struct vhost_net *net = container_of(work, struct vhost_net, 1273 poll[VHOST_NET_VQ_TX].work); 1274 handle_tx(net); 1275} 1276 1277static void handle_rx_net(struct vhost_work *work) 1278{ 1279 struct vhost_net *net = container_of(work, struct vhost_net, 1280 poll[VHOST_NET_VQ_RX].work); 1281 handle_rx(net); 1282} 1283 1284static int vhost_net_open(struct inode *inode, struct file *f) 1285{ 1286 struct vhost_net *n; 1287 struct vhost_dev *dev; 1288 struct vhost_virtqueue **vqs; 1289 void **queue; 1290 struct xdp_buff *xdp; 1291 int i; 1292 1293 n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL); 1294 if (!n) 1295 return -ENOMEM; 1296 vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL); 1297 if (!vqs) { 1298 kvfree(n); 1299 return -ENOMEM; 1300 } 1301 1302 queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *), 1303 GFP_KERNEL); 1304 if (!queue) { 1305 kfree(vqs); 1306 kvfree(n); 1307 return -ENOMEM; 1308 } 1309 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue; 1310 1311 xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL); 1312 if (!xdp) { 1313 kfree(vqs); 1314 kvfree(n); 1315 kfree(queue); 1316 return -ENOMEM; 1317 } 1318 n->vqs[VHOST_NET_VQ_TX].xdp = xdp; 1319 1320 dev = &n->dev; 1321 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; 1322 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; 1323 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; 1324 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; 1325 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 1326 n->vqs[i].ubufs = NULL; 1327 n->vqs[i].ubuf_info = NULL; 1328 n->vqs[i].upend_idx = 0; 1329 n->vqs[i].done_idx = 0; 1330 n->vqs[i].batched_xdp = 0; 1331 n->vqs[i].vhost_hlen = 0; 1332 n->vqs[i].sock_hlen = 0; 1333 n->vqs[i].rx_ring = NULL; 1334 vhost_net_buf_init(&n->vqs[i].rxq); 1335 } 1336 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX, 1337 UIO_MAXIOV + VHOST_NET_BATCH, 1338 VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT, true, 1339 NULL); 1340 1341 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev); 1342 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev); 1343 1344 f->private_data = n; 1345 n->page_frag.page = NULL; 1346 n->refcnt_bias = 0; 1347 1348 return 0; 1349} 1350 1351static struct socket *vhost_net_stop_vq(struct vhost_net *n, 1352 struct vhost_virtqueue *vq) 1353{ 1354 struct socket *sock; 1355 struct vhost_net_virtqueue *nvq = 1356 container_of(vq, struct vhost_net_virtqueue, vq); 1357 1358 mutex_lock(&vq->mutex); 1359 sock = vhost_vq_get_backend(vq); 1360 vhost_net_disable_vq(n, vq); 1361 vhost_vq_set_backend(vq, NULL); 1362 vhost_net_buf_unproduce(nvq); 1363 nvq->rx_ring = NULL; 1364 mutex_unlock(&vq->mutex); 1365 return sock; 1366} 1367 1368static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 1369 struct socket **rx_sock) 1370{ 1371 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); 1372 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); 1373} 1374 1375static void vhost_net_flush_vq(struct vhost_net *n, int index) 1376{ 1377 vhost_poll_flush(n->poll + index); 1378 vhost_poll_flush(&n->vqs[index].vq.poll); 1379} 1380 1381static void vhost_net_flush(struct vhost_net *n) 1382{ 1383 vhost_net_flush_vq(n, VHOST_NET_VQ_TX); 1384 vhost_net_flush_vq(n, VHOST_NET_VQ_RX); 1385 if (n->vqs[VHOST_NET_VQ_TX].ubufs) { 1386 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1387 n->tx_flush = true; 1388 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1389 /* Wait for all lower device DMAs done. */ 1390 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); 1391 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1392 n->tx_flush = false; 1393 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); 1394 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1395 } 1396} 1397 1398static int vhost_net_release(struct inode *inode, struct file *f) 1399{ 1400 struct vhost_net *n = f->private_data; 1401 struct socket *tx_sock; 1402 struct socket *rx_sock; 1403 1404 vhost_net_stop(n, &tx_sock, &rx_sock); 1405 vhost_net_flush(n); 1406 vhost_dev_stop(&n->dev); 1407 vhost_dev_cleanup(&n->dev); 1408 vhost_net_vq_reset(n); 1409 if (tx_sock) 1410 sockfd_put(tx_sock); 1411 if (rx_sock) 1412 sockfd_put(rx_sock); 1413 /* Make sure no callbacks are outstanding */ 1414 synchronize_rcu(); 1415 /* We do an extra flush before freeing memory, 1416 * since jobs can re-queue themselves. */ 1417 vhost_net_flush(n); 1418 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue); 1419 kfree(n->vqs[VHOST_NET_VQ_TX].xdp); 1420 kfree(n->dev.vqs); 1421 if (n->page_frag.page) 1422 __page_frag_cache_drain(n->page_frag.page, n->refcnt_bias); 1423 kvfree(n); 1424 return 0; 1425} 1426 1427static struct socket *get_raw_socket(int fd) 1428{ 1429 int r; 1430 struct socket *sock = sockfd_lookup(fd, &r); 1431 1432 if (!sock) 1433 return ERR_PTR(-ENOTSOCK); 1434 1435 /* Parameter checking */ 1436 if (sock->sk->sk_type != SOCK_RAW) { 1437 r = -ESOCKTNOSUPPORT; 1438 goto err; 1439 } 1440 1441 if (sock->sk->sk_family != AF_PACKET) { 1442 r = -EPFNOSUPPORT; 1443 goto err; 1444 } 1445 return sock; 1446err: 1447 sockfd_put(sock); 1448 return ERR_PTR(r); 1449} 1450 1451static struct ptr_ring *get_tap_ptr_ring(struct file *file) 1452{ 1453 struct ptr_ring *ring; 1454 ring = tun_get_tx_ring(file); 1455 if (!IS_ERR(ring)) 1456 goto out; 1457 ring = tap_get_ptr_ring(file); 1458 if (!IS_ERR(ring)) 1459 goto out; 1460 ring = NULL; 1461out: 1462 return ring; 1463} 1464 1465static struct socket *get_tap_socket(int fd) 1466{ 1467 struct file *file = fget(fd); 1468 struct socket *sock; 1469 1470 if (!file) 1471 return ERR_PTR(-EBADF); 1472 sock = tun_get_socket(file); 1473 if (!IS_ERR(sock)) 1474 return sock; 1475 sock = tap_get_socket(file); 1476 if (IS_ERR(sock)) 1477 fput(file); 1478 return sock; 1479} 1480 1481static struct socket *get_socket(int fd) 1482{ 1483 struct socket *sock; 1484 1485 /* special case to disable backend */ 1486 if (fd == -1) 1487 return NULL; 1488 sock = get_raw_socket(fd); 1489 if (!IS_ERR(sock)) 1490 return sock; 1491 sock = get_tap_socket(fd); 1492 if (!IS_ERR(sock)) 1493 return sock; 1494 return ERR_PTR(-ENOTSOCK); 1495} 1496 1497static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 1498{ 1499 struct socket *sock, *oldsock; 1500 struct vhost_virtqueue *vq; 1501 struct vhost_net_virtqueue *nvq; 1502 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; 1503 int r; 1504 1505 mutex_lock(&n->dev.mutex); 1506 r = vhost_dev_check_owner(&n->dev); 1507 if (r) 1508 goto err; 1509 1510 if (index >= VHOST_NET_VQ_MAX) { 1511 r = -ENOBUFS; 1512 goto err; 1513 } 1514 vq = &n->vqs[index].vq; 1515 nvq = &n->vqs[index]; 1516 mutex_lock(&vq->mutex); 1517 1518 if (fd == -1) 1519 vhost_clear_msg(&n->dev); 1520 1521 /* Verify that ring has been setup correctly. */ 1522 if (!vhost_vq_access_ok(vq)) { 1523 r = -EFAULT; 1524 goto err_vq; 1525 } 1526 sock = get_socket(fd); 1527 if (IS_ERR(sock)) { 1528 r = PTR_ERR(sock); 1529 goto err_vq; 1530 } 1531 1532 /* start polling new socket */ 1533 oldsock = vhost_vq_get_backend(vq); 1534 if (sock != oldsock) { 1535 ubufs = vhost_net_ubuf_alloc(vq, 1536 sock && vhost_sock_zcopy(sock)); 1537 if (IS_ERR(ubufs)) { 1538 r = PTR_ERR(ubufs); 1539 goto err_ubufs; 1540 } 1541 1542 vhost_net_disable_vq(n, vq); 1543 vhost_vq_set_backend(vq, sock); 1544 vhost_net_buf_unproduce(nvq); 1545 r = vhost_vq_init_access(vq); 1546 if (r) 1547 goto err_used; 1548 r = vhost_net_enable_vq(n, vq); 1549 if (r) 1550 goto err_used; 1551 if (index == VHOST_NET_VQ_RX) { 1552 if (sock) 1553 nvq->rx_ring = get_tap_ptr_ring(sock->file); 1554 else 1555 nvq->rx_ring = NULL; 1556 } 1557 1558 oldubufs = nvq->ubufs; 1559 nvq->ubufs = ubufs; 1560 1561 n->tx_packets = 0; 1562 n->tx_zcopy_err = 0; 1563 n->tx_flush = false; 1564 } 1565 1566 mutex_unlock(&vq->mutex); 1567 1568 if (oldubufs) { 1569 vhost_net_ubuf_put_wait_and_free(oldubufs); 1570 mutex_lock(&vq->mutex); 1571 vhost_zerocopy_signal_used(n, vq); 1572 mutex_unlock(&vq->mutex); 1573 } 1574 1575 if (oldsock) { 1576 vhost_net_flush_vq(n, index); 1577 sockfd_put(oldsock); 1578 } 1579 1580 mutex_unlock(&n->dev.mutex); 1581 return 0; 1582 1583err_used: 1584 vhost_vq_set_backend(vq, oldsock); 1585 vhost_net_enable_vq(n, vq); 1586 if (ubufs) 1587 vhost_net_ubuf_put_wait_and_free(ubufs); 1588err_ubufs: 1589 if (sock) 1590 sockfd_put(sock); 1591err_vq: 1592 mutex_unlock(&vq->mutex); 1593err: 1594 mutex_unlock(&n->dev.mutex); 1595 return r; 1596} 1597 1598static long vhost_net_reset_owner(struct vhost_net *n) 1599{ 1600 struct socket *tx_sock = NULL; 1601 struct socket *rx_sock = NULL; 1602 long err; 1603 struct vhost_iotlb *umem; 1604 1605 mutex_lock(&n->dev.mutex); 1606 err = vhost_dev_check_owner(&n->dev); 1607 if (err) 1608 goto done; 1609 umem = vhost_dev_reset_owner_prepare(); 1610 if (!umem) { 1611 err = -ENOMEM; 1612 goto done; 1613 } 1614 vhost_net_stop(n, &tx_sock, &rx_sock); 1615 vhost_net_flush(n); 1616 vhost_dev_stop(&n->dev); 1617 vhost_dev_reset_owner(&n->dev, umem); 1618 vhost_net_vq_reset(n); 1619done: 1620 mutex_unlock(&n->dev.mutex); 1621 if (tx_sock) 1622 sockfd_put(tx_sock); 1623 if (rx_sock) 1624 sockfd_put(rx_sock); 1625 return err; 1626} 1627 1628static int vhost_net_set_features(struct vhost_net *n, u64 features) 1629{ 1630 size_t vhost_hlen, sock_hlen, hdr_len; 1631 int i; 1632 1633 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | 1634 (1ULL << VIRTIO_F_VERSION_1))) ? 1635 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 1636 sizeof(struct virtio_net_hdr); 1637 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 1638 /* vhost provides vnet_hdr */ 1639 vhost_hlen = hdr_len; 1640 sock_hlen = 0; 1641 } else { 1642 /* socket provides vnet_hdr */ 1643 vhost_hlen = 0; 1644 sock_hlen = hdr_len; 1645 } 1646 mutex_lock(&n->dev.mutex); 1647 if ((features & (1 << VHOST_F_LOG_ALL)) && 1648 !vhost_log_access_ok(&n->dev)) 1649 goto out_unlock; 1650 1651 if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) { 1652 if (vhost_init_device_iotlb(&n->dev, true)) 1653 goto out_unlock; 1654 } 1655 1656 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1657 mutex_lock(&n->vqs[i].vq.mutex); 1658 n->vqs[i].vq.acked_features = features; 1659 n->vqs[i].vhost_hlen = vhost_hlen; 1660 n->vqs[i].sock_hlen = sock_hlen; 1661 mutex_unlock(&n->vqs[i].vq.mutex); 1662 } 1663 mutex_unlock(&n->dev.mutex); 1664 return 0; 1665 1666out_unlock: 1667 mutex_unlock(&n->dev.mutex); 1668 return -EFAULT; 1669} 1670 1671static long vhost_net_set_owner(struct vhost_net *n) 1672{ 1673 int r; 1674 1675 mutex_lock(&n->dev.mutex); 1676 if (vhost_dev_has_owner(&n->dev)) { 1677 r = -EBUSY; 1678 goto out; 1679 } 1680 r = vhost_net_set_ubuf_info(n); 1681 if (r) 1682 goto out; 1683 r = vhost_dev_set_owner(&n->dev); 1684 if (r) 1685 vhost_net_clear_ubuf_info(n); 1686 vhost_net_flush(n); 1687out: 1688 mutex_unlock(&n->dev.mutex); 1689 return r; 1690} 1691 1692static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 1693 unsigned long arg) 1694{ 1695 struct vhost_net *n = f->private_data; 1696 void __user *argp = (void __user *)arg; 1697 u64 __user *featurep = argp; 1698 struct vhost_vring_file backend; 1699 u64 features; 1700 int r; 1701 1702 switch (ioctl) { 1703 case VHOST_NET_SET_BACKEND: 1704 if (copy_from_user(&backend, argp, sizeof backend)) 1705 return -EFAULT; 1706 return vhost_net_set_backend(n, backend.index, backend.fd); 1707 case VHOST_GET_FEATURES: 1708 features = VHOST_NET_FEATURES; 1709 if (copy_to_user(featurep, &features, sizeof features)) 1710 return -EFAULT; 1711 return 0; 1712 case VHOST_SET_FEATURES: 1713 if (copy_from_user(&features, featurep, sizeof features)) 1714 return -EFAULT; 1715 if (features & ~VHOST_NET_FEATURES) 1716 return -EOPNOTSUPP; 1717 return vhost_net_set_features(n, features); 1718 case VHOST_GET_BACKEND_FEATURES: 1719 features = VHOST_NET_BACKEND_FEATURES; 1720 if (copy_to_user(featurep, &features, sizeof(features))) 1721 return -EFAULT; 1722 return 0; 1723 case VHOST_SET_BACKEND_FEATURES: 1724 if (copy_from_user(&features, featurep, sizeof(features))) 1725 return -EFAULT; 1726 if (features & ~VHOST_NET_BACKEND_FEATURES) 1727 return -EOPNOTSUPP; 1728 vhost_set_backend_features(&n->dev, features); 1729 return 0; 1730 case VHOST_RESET_OWNER: 1731 return vhost_net_reset_owner(n); 1732 case VHOST_SET_OWNER: 1733 return vhost_net_set_owner(n); 1734 default: 1735 mutex_lock(&n->dev.mutex); 1736 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 1737 if (r == -ENOIOCTLCMD) 1738 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 1739 else 1740 vhost_net_flush(n); 1741 mutex_unlock(&n->dev.mutex); 1742 return r; 1743 } 1744} 1745 1746static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1747{ 1748 struct file *file = iocb->ki_filp; 1749 struct vhost_net *n = file->private_data; 1750 struct vhost_dev *dev = &n->dev; 1751 int noblock = file->f_flags & O_NONBLOCK; 1752 1753 return vhost_chr_read_iter(dev, to, noblock); 1754} 1755 1756static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb, 1757 struct iov_iter *from) 1758{ 1759 struct file *file = iocb->ki_filp; 1760 struct vhost_net *n = file->private_data; 1761 struct vhost_dev *dev = &n->dev; 1762 1763 return vhost_chr_write_iter(dev, from); 1764} 1765 1766static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait) 1767{ 1768 struct vhost_net *n = file->private_data; 1769 struct vhost_dev *dev = &n->dev; 1770 1771 return vhost_chr_poll(file, dev, wait); 1772} 1773 1774static const struct file_operations vhost_net_fops = { 1775 .owner = THIS_MODULE, 1776 .release = vhost_net_release, 1777 .read_iter = vhost_net_chr_read_iter, 1778 .write_iter = vhost_net_chr_write_iter, 1779 .poll = vhost_net_chr_poll, 1780 .unlocked_ioctl = vhost_net_ioctl, 1781 .compat_ioctl = compat_ptr_ioctl, 1782 .open = vhost_net_open, 1783 .llseek = noop_llseek, 1784}; 1785 1786static struct miscdevice vhost_net_misc = { 1787 .minor = VHOST_NET_MINOR, 1788 .name = "vhost-net", 1789 .fops = &vhost_net_fops, 1790}; 1791 1792static int vhost_net_init(void) 1793{ 1794 if (experimental_zcopytx) 1795 vhost_net_enable_zcopy(VHOST_NET_VQ_TX); 1796 return misc_register(&vhost_net_misc); 1797} 1798module_init(vhost_net_init); 1799 1800static void vhost_net_exit(void) 1801{ 1802 misc_deregister(&vhost_net_misc); 1803} 1804module_exit(vhost_net_exit); 1805 1806MODULE_VERSION("0.0.1"); 1807MODULE_LICENSE("GPL v2"); 1808MODULE_AUTHOR("Michael S. Tsirkin"); 1809MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1810MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1811MODULE_ALIAS("devname:vhost-net"); 1812