1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * vhost transport for vsock 4 * 5 * Copyright (C) 2013-2015 Red Hat, Inc. 6 * Author: Asias He <asias@redhat.com> 7 * Stefan Hajnoczi <stefanha@redhat.com> 8 */ 9 #include <linux/miscdevice.h> 10 #include <linux/atomic.h> 11 #include <linux/module.h> 12 #include <linux/mutex.h> 13 #include <linux/vmalloc.h> 14 #include <net/sock.h> 15 #include <linux/virtio_vsock.h> 16 #include <linux/vhost.h> 17 #include <linux/hashtable.h> 18 19 #include <net/af_vsock.h> 20 #include "vhost.h" 21 22 #define VHOST_VSOCK_DEFAULT_HOST_CID 2 23 /* Max number of bytes transferred before requeueing the job. 24 * Using this limit prevents one virtqueue from starving others. */ 25 #define VHOST_VSOCK_WEIGHT 0x80000 26 /* Max number of packets transferred before requeueing the job. 27 * Using this limit prevents one virtqueue from starving others with 28 * small pkts. 29 */ 30 #define VHOST_VSOCK_PKT_WEIGHT 256 31 32 static const int vhost_vsock_bits[] = { 33 VHOST_FEATURES, 34 VIRTIO_F_ACCESS_PLATFORM, 35 VIRTIO_VSOCK_F_SEQPACKET 36 }; 37 38 #define VHOST_VSOCK_FEATURES VHOST_FEATURES_U64(vhost_vsock_bits, 0) 39 40 enum { 41 VHOST_VSOCK_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) 42 }; 43 44 /* Used to track all the vhost_vsock instances on the system. */ 45 static DEFINE_MUTEX(vhost_vsock_mutex); 46 static DEFINE_READ_MOSTLY_HASHTABLE(vhost_vsock_hash, 8); 47 48 struct vhost_vsock { 49 struct vhost_dev dev; 50 struct vhost_virtqueue vqs[2]; 51 struct net *net; 52 netns_tracker ns_tracker; 53 54 /* Link to global vhost_vsock_hash, writes use vhost_vsock_mutex */ 55 struct hlist_node hash; 56 57 struct vhost_work send_pkt_work; 58 struct sk_buff_head send_pkt_queue; /* host->guest pending packets */ 59 60 atomic_t queued_replies; 61 62 u32 guest_cid; 63 bool seqpacket_allow; 64 }; 65 66 static u32 vhost_transport_get_local_cid(void) 67 { 68 return VHOST_VSOCK_DEFAULT_HOST_CID; 69 } 70 71 /* Callers must be in an RCU read section or hold the vhost_vsock_mutex. 72 * The return value can only be dereferenced while within the section. 73 */ 74 static struct vhost_vsock *vhost_vsock_get(u32 guest_cid, struct net *net) 75 { 76 struct vhost_vsock *vsock; 77 78 hash_for_each_possible_rcu(vhost_vsock_hash, vsock, hash, guest_cid, 79 lockdep_is_held(&vhost_vsock_mutex)) { 80 u32 other_cid = vsock->guest_cid; 81 82 /* Skip instances that have no CID yet */ 83 if (other_cid == 0) 84 continue; 85 86 if (other_cid == guest_cid && 87 vsock_net_check_mode(net, vsock->net)) 88 return vsock; 89 } 90 91 return NULL; 92 } 93 94 static bool vhost_transport_has_remote_cid(struct vsock_sock *vsk, u32 cid) 95 { 96 struct sock *sk = sk_vsock(vsk); 97 struct net *net = sock_net(sk); 98 bool found; 99 100 rcu_read_lock(); 101 found = !!vhost_vsock_get(cid, net); 102 rcu_read_unlock(); 103 return found; 104 } 105 106 static void 107 vhost_transport_do_send_pkt(struct vhost_vsock *vsock, 108 struct vhost_virtqueue *vq) 109 { 110 struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX]; 111 int pkts = 0, total_len = 0; 112 bool added = false; 113 bool restart_tx = false; 114 115 mutex_lock(&vq->mutex); 116 117 if (!vhost_vq_get_backend(vq)) 118 goto out; 119 120 if (!vq_meta_prefetch(vq)) 121 goto out; 122 123 /* Avoid further vmexits, we're already processing the virtqueue */ 124 vhost_disable_notify(&vsock->dev, vq); 125 126 do { 127 struct virtio_vsock_hdr *hdr; 128 size_t iov_len, payload_len; 129 struct iov_iter iov_iter; 130 u32 flags_to_restore = 0; 131 struct sk_buff *skb; 132 unsigned out, in; 133 size_t nbytes; 134 u32 offset; 135 int head; 136 137 skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue); 138 139 if (!skb) { 140 vhost_enable_notify(&vsock->dev, vq); 141 break; 142 } 143 144 head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), 145 &out, &in, NULL, NULL); 146 if (head < 0) { 147 virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb); 148 break; 149 } 150 151 if (head == vq->num) { 152 virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb); 153 /* We cannot finish yet if more buffers snuck in while 154 * re-enabling notify. 155 */ 156 if (unlikely(vhost_enable_notify(&vsock->dev, vq))) { 157 vhost_disable_notify(&vsock->dev, vq); 158 continue; 159 } 160 break; 161 } 162 163 if (out) { 164 kfree_skb(skb); 165 vq_err(vq, "Expected 0 output buffers, got %u\n", out); 166 break; 167 } 168 169 iov_len = iov_length(&vq->iov[out], in); 170 if (iov_len < sizeof(*hdr)) { 171 kfree_skb(skb); 172 vq_err(vq, "Buffer len [%zu] too small\n", iov_len); 173 break; 174 } 175 176 iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[out], in, iov_len); 177 offset = VIRTIO_VSOCK_SKB_CB(skb)->offset; 178 payload_len = skb->len - offset; 179 hdr = virtio_vsock_hdr(skb); 180 181 /* If the packet is greater than the space available in the 182 * buffer, we split it using multiple buffers. 183 */ 184 if (payload_len > iov_len - sizeof(*hdr)) { 185 payload_len = iov_len - sizeof(*hdr); 186 187 /* As we are copying pieces of large packet's buffer to 188 * small rx buffers, headers of packets in rx queue are 189 * created dynamically and are initialized with header 190 * of current packet(except length). But in case of 191 * SOCK_SEQPACKET, we also must clear message delimeter 192 * bit (VIRTIO_VSOCK_SEQ_EOM) and MSG_EOR bit 193 * (VIRTIO_VSOCK_SEQ_EOR) if set. Otherwise, 194 * there will be sequence of packets with these 195 * bits set. After initialized header will be copied to 196 * rx buffer, these required bits will be restored. 197 */ 198 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) { 199 hdr->flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM); 200 flags_to_restore |= VIRTIO_VSOCK_SEQ_EOM; 201 202 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR) { 203 hdr->flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR); 204 flags_to_restore |= VIRTIO_VSOCK_SEQ_EOR; 205 } 206 } 207 } 208 209 /* Set the correct length in the header */ 210 hdr->len = cpu_to_le32(payload_len); 211 212 nbytes = copy_to_iter(hdr, sizeof(*hdr), &iov_iter); 213 if (nbytes != sizeof(*hdr)) { 214 kfree_skb(skb); 215 vq_err(vq, "Faulted on copying pkt hdr\n"); 216 break; 217 } 218 219 if (skb_copy_datagram_iter(skb, 220 offset, 221 &iov_iter, 222 payload_len)) { 223 kfree_skb(skb); 224 vq_err(vq, "Faulted on copying pkt buf\n"); 225 break; 226 } 227 228 /* Deliver to monitoring devices all packets that we 229 * will transmit. 230 */ 231 virtio_transport_deliver_tap_pkt(skb); 232 233 vhost_add_used(vq, head, sizeof(*hdr) + payload_len); 234 added = true; 235 236 VIRTIO_VSOCK_SKB_CB(skb)->offset += payload_len; 237 total_len += payload_len; 238 239 /* If we didn't send all the payload we can requeue the packet 240 * to send it with the next available buffer. 241 */ 242 if (VIRTIO_VSOCK_SKB_CB(skb)->offset < skb->len) { 243 hdr->flags |= cpu_to_le32(flags_to_restore); 244 245 /* We are queueing the same skb to handle 246 * the remaining bytes, and we want to deliver it 247 * to monitoring devices in the next iteration. 248 */ 249 virtio_vsock_skb_clear_tap_delivered(skb); 250 virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb); 251 } else { 252 if (virtio_vsock_skb_reply(skb)) { 253 int val; 254 255 val = atomic_dec_return(&vsock->queued_replies); 256 257 /* Do we have resources to resume tx 258 * processing? 259 */ 260 if (val + 1 == tx_vq->num) 261 restart_tx = true; 262 } 263 264 virtio_transport_consume_skb_sent(skb, true); 265 } 266 } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len))); 267 if (added) 268 vhost_signal(&vsock->dev, vq); 269 270 out: 271 mutex_unlock(&vq->mutex); 272 273 if (restart_tx) 274 vhost_poll_queue(&tx_vq->poll); 275 } 276 277 static void vhost_transport_send_pkt_work(struct vhost_work *work) 278 { 279 struct vhost_virtqueue *vq; 280 struct vhost_vsock *vsock; 281 282 vsock = container_of(work, struct vhost_vsock, send_pkt_work); 283 vq = &vsock->vqs[VSOCK_VQ_RX]; 284 285 vhost_transport_do_send_pkt(vsock, vq); 286 } 287 288 static int 289 vhost_transport_send_pkt(struct sk_buff *skb, struct net *net) 290 { 291 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb); 292 struct vhost_vsock *vsock; 293 int len = skb->len; 294 295 rcu_read_lock(); 296 297 /* Find the vhost_vsock according to guest context id */ 298 vsock = vhost_vsock_get(le64_to_cpu(hdr->dst_cid), net); 299 if (!vsock) { 300 rcu_read_unlock(); 301 kfree_skb(skb); 302 return -ENODEV; 303 } 304 305 /* Fast-fail if the guest hasn't enabled the RX vq yet. Queuing the packet 306 * and making the caller wait is pointless: even if the guest manages to init 307 * within the timeout, it'll immediately reply with RST, because there's no 308 * listener on the port yet. 309 * 310 * vhost_vq_get_backend() without vq->mutex is acceptable here: locking 311 * the mutex would be too expensive in this hot path, and we already have 312 * all the outcomes covered: if the backend becomes NULL right after the check, 313 * vhost_transport_do_send_pkt() will check it under the mutex anyway. 314 */ 315 if (unlikely(!data_race(vhost_vq_get_backend(&vsock->vqs[VSOCK_VQ_RX])))) { 316 rcu_read_unlock(); 317 kfree_skb(skb); 318 return -EHOSTUNREACH; 319 } 320 321 if (virtio_vsock_skb_reply(skb)) 322 atomic_inc(&vsock->queued_replies); 323 324 virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb); 325 vhost_vq_work_queue(&vsock->vqs[VSOCK_VQ_RX], &vsock->send_pkt_work); 326 327 rcu_read_unlock(); 328 return len; 329 } 330 331 static int 332 vhost_transport_cancel_pkt(struct vsock_sock *vsk) 333 { 334 struct vhost_vsock *vsock; 335 int cnt = 0; 336 int ret = -ENODEV; 337 338 rcu_read_lock(); 339 340 /* Find the vhost_vsock according to guest context id */ 341 vsock = vhost_vsock_get(vsk->remote_addr.svm_cid, 342 sock_net(sk_vsock(vsk))); 343 if (!vsock) 344 goto out; 345 346 cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue); 347 348 if (cnt) { 349 struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX]; 350 int new_cnt; 351 352 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies); 353 if (new_cnt + cnt >= tx_vq->num && new_cnt < tx_vq->num) 354 vhost_poll_queue(&tx_vq->poll); 355 } 356 357 ret = 0; 358 out: 359 rcu_read_unlock(); 360 return ret; 361 } 362 363 static struct sk_buff * 364 vhost_vsock_alloc_skb(struct vhost_virtqueue *vq, 365 unsigned int out, unsigned int in) 366 { 367 struct virtio_vsock_hdr *hdr; 368 struct iov_iter iov_iter; 369 struct sk_buff *skb; 370 size_t payload_len; 371 size_t nbytes; 372 size_t len; 373 374 if (in != 0) { 375 vq_err(vq, "Expected 0 input buffers, got %u\n", in); 376 return NULL; 377 } 378 379 len = iov_length(vq->iov, out); 380 381 if (len < VIRTIO_VSOCK_SKB_HEADROOM || 382 len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM) 383 return NULL; 384 385 /* len contains both payload and hdr */ 386 skb = virtio_vsock_alloc_skb(len, GFP_KERNEL); 387 if (!skb) 388 return NULL; 389 390 iov_iter_init(&iov_iter, ITER_SOURCE, vq->iov, out, len); 391 392 hdr = virtio_vsock_hdr(skb); 393 nbytes = copy_from_iter(hdr, sizeof(*hdr), &iov_iter); 394 if (nbytes != sizeof(*hdr)) { 395 vq_err(vq, "Expected %zu bytes for pkt->hdr, got %zu bytes\n", 396 sizeof(*hdr), nbytes); 397 kfree_skb(skb); 398 return NULL; 399 } 400 401 payload_len = le32_to_cpu(hdr->len); 402 403 /* No payload */ 404 if (!payload_len) 405 return skb; 406 407 /* The pkt is too big or the length in the header is invalid */ 408 if (payload_len + sizeof(*hdr) > len) { 409 kfree_skb(skb); 410 return NULL; 411 } 412 413 virtio_vsock_skb_put(skb, payload_len); 414 415 if (skb_copy_datagram_from_iter(skb, 0, &iov_iter, payload_len)) { 416 vq_err(vq, "Failed to copy %zu byte payload\n", payload_len); 417 kfree_skb(skb); 418 return NULL; 419 } 420 421 return skb; 422 } 423 424 /* Is there space left for replies to rx packets? */ 425 static bool vhost_vsock_more_replies(struct vhost_vsock *vsock) 426 { 427 struct vhost_virtqueue *vq = &vsock->vqs[VSOCK_VQ_TX]; 428 int val; 429 430 smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */ 431 val = atomic_read(&vsock->queued_replies); 432 433 return val < vq->num; 434 } 435 436 static bool vhost_transport_msgzerocopy_allow(void) 437 { 438 return true; 439 } 440 441 static bool vhost_transport_seqpacket_allow(struct vsock_sock *vsk, 442 u32 remote_cid); 443 444 static bool 445 vhost_transport_stream_allow(struct vsock_sock *vsk, u32 cid, u32 port) 446 { 447 return true; 448 } 449 450 static struct virtio_transport vhost_transport = { 451 .transport = { 452 .module = THIS_MODULE, 453 454 .get_local_cid = vhost_transport_get_local_cid, 455 .has_remote_cid = vhost_transport_has_remote_cid, 456 457 .init = virtio_transport_do_socket_init, 458 .destruct = virtio_transport_destruct, 459 .release = virtio_transport_release, 460 .connect = virtio_transport_connect, 461 .shutdown = virtio_transport_shutdown, 462 .cancel_pkt = vhost_transport_cancel_pkt, 463 464 .dgram_enqueue = virtio_transport_dgram_enqueue, 465 .dgram_dequeue = virtio_transport_dgram_dequeue, 466 .dgram_bind = virtio_transport_dgram_bind, 467 .dgram_allow = virtio_transport_dgram_allow, 468 469 .stream_enqueue = virtio_transport_stream_enqueue, 470 .stream_dequeue = virtio_transport_stream_dequeue, 471 .stream_has_data = virtio_transport_stream_has_data, 472 .stream_has_space = virtio_transport_stream_has_space, 473 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat, 474 .stream_is_active = virtio_transport_stream_is_active, 475 .stream_allow = vhost_transport_stream_allow, 476 477 .seqpacket_dequeue = virtio_transport_seqpacket_dequeue, 478 .seqpacket_enqueue = virtio_transport_seqpacket_enqueue, 479 .seqpacket_allow = vhost_transport_seqpacket_allow, 480 .seqpacket_has_data = virtio_transport_seqpacket_has_data, 481 482 .msgzerocopy_allow = vhost_transport_msgzerocopy_allow, 483 484 .notify_poll_in = virtio_transport_notify_poll_in, 485 .notify_poll_out = virtio_transport_notify_poll_out, 486 .notify_recv_init = virtio_transport_notify_recv_init, 487 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block, 488 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue, 489 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue, 490 .notify_send_init = virtio_transport_notify_send_init, 491 .notify_send_pre_block = virtio_transport_notify_send_pre_block, 492 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue, 493 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue, 494 .notify_buffer_size = virtio_transport_notify_buffer_size, 495 .notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat, 496 497 .unsent_bytes = virtio_transport_unsent_bytes, 498 499 .read_skb = virtio_transport_read_skb, 500 }, 501 502 .send_pkt = vhost_transport_send_pkt, 503 }; 504 505 static bool vhost_transport_seqpacket_allow(struct vsock_sock *vsk, 506 u32 remote_cid) 507 { 508 struct net *net = sock_net(sk_vsock(vsk)); 509 struct vhost_vsock *vsock; 510 bool seqpacket_allow = false; 511 512 rcu_read_lock(); 513 vsock = vhost_vsock_get(remote_cid, net); 514 515 if (vsock) 516 seqpacket_allow = vsock->seqpacket_allow; 517 518 rcu_read_unlock(); 519 520 return seqpacket_allow; 521 } 522 523 static void vhost_vsock_handle_tx_kick(struct vhost_work *work) 524 { 525 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 526 poll.work); 527 struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock, 528 dev); 529 int head, pkts = 0, total_len = 0; 530 unsigned int out, in; 531 struct sk_buff *skb; 532 bool added = false; 533 534 mutex_lock(&vq->mutex); 535 536 if (!vhost_vq_get_backend(vq)) 537 goto out; 538 539 if (!vq_meta_prefetch(vq)) 540 goto out; 541 542 vhost_disable_notify(&vsock->dev, vq); 543 do { 544 struct virtio_vsock_hdr *hdr; 545 546 if (!vhost_vsock_more_replies(vsock)) { 547 /* Stop tx until the device processes already 548 * pending replies. Leave tx virtqueue 549 * callbacks disabled. 550 */ 551 goto no_more_replies; 552 } 553 554 head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), 555 &out, &in, NULL, NULL); 556 if (head < 0) 557 break; 558 559 if (head == vq->num) { 560 if (unlikely(vhost_enable_notify(&vsock->dev, vq))) { 561 vhost_disable_notify(&vsock->dev, vq); 562 continue; 563 } 564 break; 565 } 566 567 skb = vhost_vsock_alloc_skb(vq, out, in); 568 if (!skb) { 569 vq_err(vq, "Faulted on pkt\n"); 570 continue; 571 } 572 573 total_len += sizeof(*hdr) + skb->len; 574 575 /* Deliver to monitoring devices all received packets */ 576 virtio_transport_deliver_tap_pkt(skb); 577 578 hdr = virtio_vsock_hdr(skb); 579 580 /* Only accept correctly addressed packets */ 581 if (le64_to_cpu(hdr->src_cid) == vsock->guest_cid && 582 le64_to_cpu(hdr->dst_cid) == 583 vhost_transport_get_local_cid()) 584 virtio_transport_recv_pkt(&vhost_transport, skb, 585 vsock->net); 586 else 587 kfree_skb(skb); 588 589 vhost_add_used(vq, head, 0); 590 added = true; 591 } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len))); 592 593 no_more_replies: 594 if (added) 595 vhost_signal(&vsock->dev, vq); 596 597 out: 598 mutex_unlock(&vq->mutex); 599 } 600 601 static void vhost_vsock_handle_rx_kick(struct vhost_work *work) 602 { 603 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 604 poll.work); 605 struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock, 606 dev); 607 608 vhost_transport_do_send_pkt(vsock, vq); 609 } 610 611 static int vhost_vsock_start(struct vhost_vsock *vsock) 612 { 613 struct vhost_virtqueue *vq; 614 size_t i; 615 int ret; 616 617 mutex_lock(&vsock->dev.mutex); 618 619 ret = vhost_dev_check_owner(&vsock->dev); 620 if (ret) 621 goto err; 622 623 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { 624 vq = &vsock->vqs[i]; 625 626 mutex_lock(&vq->mutex); 627 628 if (!vhost_vq_access_ok(vq)) { 629 ret = -EFAULT; 630 goto err_vq; 631 } 632 633 if (!vhost_vq_get_backend(vq)) { 634 vhost_vq_set_backend(vq, vsock); 635 ret = vhost_vq_init_access(vq); 636 if (ret) 637 goto err_vq; 638 } 639 640 mutex_unlock(&vq->mutex); 641 } 642 643 /* Some packets may have been queued before the device was started, 644 * let's kick the send worker to send them. 645 */ 646 vhost_vq_work_queue(&vsock->vqs[VSOCK_VQ_RX], &vsock->send_pkt_work); 647 648 mutex_unlock(&vsock->dev.mutex); 649 return 0; 650 651 err_vq: 652 vhost_vq_set_backend(vq, NULL); 653 mutex_unlock(&vq->mutex); 654 655 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { 656 vq = &vsock->vqs[i]; 657 658 mutex_lock(&vq->mutex); 659 vhost_vq_set_backend(vq, NULL); 660 mutex_unlock(&vq->mutex); 661 } 662 err: 663 mutex_unlock(&vsock->dev.mutex); 664 return ret; 665 } 666 667 static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner) 668 { 669 size_t i; 670 int ret = 0; 671 672 mutex_lock(&vsock->dev.mutex); 673 674 if (check_owner) { 675 ret = vhost_dev_check_owner(&vsock->dev); 676 if (ret) 677 goto err; 678 } 679 680 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { 681 struct vhost_virtqueue *vq = &vsock->vqs[i]; 682 683 mutex_lock(&vq->mutex); 684 vhost_vq_set_backend(vq, NULL); 685 mutex_unlock(&vq->mutex); 686 } 687 688 err: 689 mutex_unlock(&vsock->dev.mutex); 690 return ret; 691 } 692 693 static void vhost_vsock_free(struct vhost_vsock *vsock) 694 { 695 kvfree(vsock); 696 } 697 698 static int vhost_vsock_dev_open(struct inode *inode, struct file *file) 699 { 700 struct vhost_virtqueue **vqs; 701 struct vhost_vsock *vsock; 702 struct net *net; 703 int ret; 704 705 /* This struct is large and allocation could fail, fall back to vmalloc 706 * if there is no other way. 707 */ 708 vsock = kvmalloc_obj(*vsock, GFP_KERNEL | __GFP_RETRY_MAYFAIL); 709 if (!vsock) 710 return -ENOMEM; 711 712 vqs = kmalloc_objs(*vqs, ARRAY_SIZE(vsock->vqs)); 713 if (!vqs) { 714 ret = -ENOMEM; 715 goto out; 716 } 717 718 net = current->nsproxy->net_ns; 719 vsock->net = get_net_track(net, &vsock->ns_tracker, GFP_KERNEL); 720 721 vsock->guest_cid = 0; /* no CID assigned yet */ 722 vsock->seqpacket_allow = false; 723 724 atomic_set(&vsock->queued_replies, 0); 725 726 vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX]; 727 vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX]; 728 vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick; 729 vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick; 730 731 vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs), 732 UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT, 733 VHOST_VSOCK_WEIGHT, true, NULL); 734 735 file->private_data = vsock; 736 skb_queue_head_init(&vsock->send_pkt_queue); 737 vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work); 738 return 0; 739 740 out: 741 vhost_vsock_free(vsock); 742 return ret; 743 } 744 745 static void vhost_vsock_flush(struct vhost_vsock *vsock) 746 { 747 vhost_dev_flush(&vsock->dev); 748 } 749 750 static void vhost_vsock_reset_orphans(struct sock *sk) 751 { 752 struct vsock_sock *vsk = vsock_sk(sk); 753 754 /* vmci_transport.c doesn't take sk_lock here either. At least we're 755 * under vsock_table_lock so the sock cannot disappear while we're 756 * executing. 757 */ 758 759 rcu_read_lock(); 760 761 /* If the peer is still valid, no need to reset connection */ 762 if (vhost_vsock_get(vsk->remote_addr.svm_cid, sock_net(sk))) { 763 rcu_read_unlock(); 764 return; 765 } 766 767 rcu_read_unlock(); 768 769 /* If the close timeout is pending, let it expire. This avoids races 770 * with the timeout callback. 771 */ 772 if (vsk->close_work_scheduled) 773 return; 774 775 sock_set_flag(sk, SOCK_DONE); 776 vsk->peer_shutdown = SHUTDOWN_MASK; 777 sk->sk_state = SS_UNCONNECTED; 778 sk->sk_err = ECONNRESET; 779 sk_error_report(sk); 780 } 781 782 static int vhost_vsock_dev_release(struct inode *inode, struct file *file) 783 { 784 struct vhost_vsock *vsock = file->private_data; 785 786 mutex_lock(&vhost_vsock_mutex); 787 if (vsock->guest_cid) 788 hash_del_rcu(&vsock->hash); 789 mutex_unlock(&vhost_vsock_mutex); 790 791 /* Wait for other CPUs to finish using vsock */ 792 synchronize_rcu(); 793 794 /* Iterating over all connections for all CIDs to find orphans is 795 * inefficient. Room for improvement here. */ 796 vsock_for_each_connected_socket(&vhost_transport.transport, 797 vhost_vsock_reset_orphans); 798 799 /* Don't check the owner, because we are in the release path, so we 800 * need to stop the vsock device in any case. 801 * vhost_vsock_stop() can not fail in this case, so we don't need to 802 * check the return code. 803 */ 804 vhost_vsock_stop(vsock, false); 805 vhost_vsock_flush(vsock); 806 vhost_dev_stop(&vsock->dev); 807 808 virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue); 809 810 vhost_dev_cleanup(&vsock->dev); 811 put_net_track(vsock->net, &vsock->ns_tracker); 812 kfree(vsock->dev.vqs); 813 vhost_vsock_free(vsock); 814 return 0; 815 } 816 817 static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid) 818 { 819 struct vhost_vsock *other; 820 821 /* Refuse reserved CIDs */ 822 if (guest_cid <= VMADDR_CID_HOST || 823 guest_cid == U32_MAX) 824 return -EINVAL; 825 826 /* 64-bit CIDs are not yet supported */ 827 if (guest_cid > U32_MAX) 828 return -EINVAL; 829 830 /* Refuse if CID is assigned to the guest->host transport (i.e. nested 831 * VM), to make the loopback work. 832 */ 833 if (vsock_find_cid(guest_cid)) 834 return -EADDRINUSE; 835 836 /* Refuse if CID is already in use */ 837 mutex_lock(&vhost_vsock_mutex); 838 other = vhost_vsock_get(guest_cid, vsock->net); 839 if (other && other != vsock) { 840 mutex_unlock(&vhost_vsock_mutex); 841 return -EADDRINUSE; 842 } 843 844 if (vsock->guest_cid) 845 hash_del_rcu(&vsock->hash); 846 847 vsock->guest_cid = guest_cid; 848 hash_add_rcu(vhost_vsock_hash, &vsock->hash, vsock->guest_cid); 849 mutex_unlock(&vhost_vsock_mutex); 850 851 return 0; 852 } 853 854 static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features) 855 { 856 struct vhost_virtqueue *vq; 857 int i; 858 859 if (features & ~VHOST_VSOCK_FEATURES) 860 return -EOPNOTSUPP; 861 862 mutex_lock(&vsock->dev.mutex); 863 if ((features & (1 << VHOST_F_LOG_ALL)) && 864 !vhost_log_access_ok(&vsock->dev)) { 865 goto err; 866 } 867 868 if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) { 869 if (vhost_init_device_iotlb(&vsock->dev)) 870 goto err; 871 } 872 873 vsock->seqpacket_allow = features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET); 874 875 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { 876 vq = &vsock->vqs[i]; 877 mutex_lock(&vq->mutex); 878 vq->acked_features = features; 879 mutex_unlock(&vq->mutex); 880 } 881 mutex_unlock(&vsock->dev.mutex); 882 return 0; 883 884 err: 885 mutex_unlock(&vsock->dev.mutex); 886 return -EFAULT; 887 } 888 889 static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl, 890 unsigned long arg) 891 { 892 struct vhost_vsock *vsock = f->private_data; 893 void __user *argp = (void __user *)arg; 894 u64 guest_cid; 895 u64 features; 896 int start; 897 int r; 898 899 switch (ioctl) { 900 case VHOST_VSOCK_SET_GUEST_CID: 901 if (copy_from_user(&guest_cid, argp, sizeof(guest_cid))) 902 return -EFAULT; 903 return vhost_vsock_set_cid(vsock, guest_cid); 904 case VHOST_VSOCK_SET_RUNNING: 905 if (copy_from_user(&start, argp, sizeof(start))) 906 return -EFAULT; 907 if (start) 908 return vhost_vsock_start(vsock); 909 else 910 return vhost_vsock_stop(vsock, true); 911 case VHOST_GET_FEATURES: 912 features = VHOST_VSOCK_FEATURES; 913 if (copy_to_user(argp, &features, sizeof(features))) 914 return -EFAULT; 915 return 0; 916 case VHOST_SET_FEATURES: 917 if (copy_from_user(&features, argp, sizeof(features))) 918 return -EFAULT; 919 return vhost_vsock_set_features(vsock, features); 920 case VHOST_GET_BACKEND_FEATURES: 921 features = VHOST_VSOCK_BACKEND_FEATURES; 922 if (copy_to_user(argp, &features, sizeof(features))) 923 return -EFAULT; 924 return 0; 925 case VHOST_SET_BACKEND_FEATURES: 926 if (copy_from_user(&features, argp, sizeof(features))) 927 return -EFAULT; 928 if (features & ~VHOST_VSOCK_BACKEND_FEATURES) 929 return -EOPNOTSUPP; 930 vhost_set_backend_features(&vsock->dev, features); 931 return 0; 932 default: 933 mutex_lock(&vsock->dev.mutex); 934 r = vhost_dev_ioctl(&vsock->dev, ioctl, argp); 935 if (r == -ENOIOCTLCMD) 936 r = vhost_vring_ioctl(&vsock->dev, ioctl, argp); 937 else 938 vhost_vsock_flush(vsock); 939 mutex_unlock(&vsock->dev.mutex); 940 return r; 941 } 942 } 943 944 static ssize_t vhost_vsock_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 945 { 946 struct file *file = iocb->ki_filp; 947 struct vhost_vsock *vsock = file->private_data; 948 struct vhost_dev *dev = &vsock->dev; 949 int noblock = file->f_flags & O_NONBLOCK; 950 951 return vhost_chr_read_iter(dev, to, noblock); 952 } 953 954 static ssize_t vhost_vsock_chr_write_iter(struct kiocb *iocb, 955 struct iov_iter *from) 956 { 957 struct file *file = iocb->ki_filp; 958 struct vhost_vsock *vsock = file->private_data; 959 struct vhost_dev *dev = &vsock->dev; 960 961 return vhost_chr_write_iter(dev, from); 962 } 963 964 static __poll_t vhost_vsock_chr_poll(struct file *file, poll_table *wait) 965 { 966 struct vhost_vsock *vsock = file->private_data; 967 struct vhost_dev *dev = &vsock->dev; 968 969 return vhost_chr_poll(file, dev, wait); 970 } 971 972 static const struct file_operations vhost_vsock_fops = { 973 .owner = THIS_MODULE, 974 .open = vhost_vsock_dev_open, 975 .release = vhost_vsock_dev_release, 976 .llseek = noop_llseek, 977 .unlocked_ioctl = vhost_vsock_dev_ioctl, 978 .compat_ioctl = compat_ptr_ioctl, 979 .read_iter = vhost_vsock_chr_read_iter, 980 .write_iter = vhost_vsock_chr_write_iter, 981 .poll = vhost_vsock_chr_poll, 982 }; 983 984 static struct miscdevice vhost_vsock_misc = { 985 .minor = VHOST_VSOCK_MINOR, 986 .name = "vhost-vsock", 987 .fops = &vhost_vsock_fops, 988 }; 989 990 static int __init vhost_vsock_init(void) 991 { 992 int ret; 993 994 ret = vsock_core_register(&vhost_transport.transport, 995 VSOCK_TRANSPORT_F_H2G); 996 if (ret < 0) 997 return ret; 998 999 ret = misc_register(&vhost_vsock_misc); 1000 if (ret) { 1001 vsock_core_unregister(&vhost_transport.transport); 1002 return ret; 1003 } 1004 1005 return 0; 1006 }; 1007 1008 static void __exit vhost_vsock_exit(void) 1009 { 1010 misc_deregister(&vhost_vsock_misc); 1011 vsock_core_unregister(&vhost_transport.transport); 1012 }; 1013 1014 module_init(vhost_vsock_init); 1015 module_exit(vhost_vsock_exit); 1016 MODULE_LICENSE("GPL v2"); 1017 MODULE_AUTHOR("Asias He"); 1018 MODULE_DESCRIPTION("vhost transport for vsock "); 1019 MODULE_ALIAS_MISCDEV(VHOST_VSOCK_MINOR); 1020 MODULE_ALIAS("devname:vhost-vsock"); 1021