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