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