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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * vhost transport for vsock4 *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 223/* Max number of bytes transferred before requeueing the job.24 * Using this limit prevents one virtqueue from starving others. */25#define VHOST_VSOCK_WEIGHT 0x8000026/* Max number of packets transferred before requeueing the job.27 * Using this limit prevents one virtqueue from starving others with28 * small pkts.29 */30#define VHOST_VSOCK_PKT_WEIGHT 25631 32enum {33 VHOST_VSOCK_FEATURES = VHOST_FEATURES |34 (1ULL << VIRTIO_F_ACCESS_PLATFORM) |35 (1ULL << VIRTIO_VSOCK_F_SEQPACKET)36};37 38enum {39 VHOST_VSOCK_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)40};41 42/* Used to track all the vhost_vsock instances on the system. */43static DEFINE_MUTEX(vhost_vsock_mutex);44static DEFINE_READ_MOSTLY_HASHTABLE(vhost_vsock_hash, 8);45 46struct vhost_vsock {47 struct vhost_dev dev;48 struct vhost_virtqueue vqs[2];49 50 /* Link to global vhost_vsock_hash, writes use vhost_vsock_mutex */51 struct hlist_node hash;52 53 struct vhost_work send_pkt_work;54 struct sk_buff_head send_pkt_queue; /* host->guest pending packets */55 56 atomic_t queued_replies;57 58 u32 guest_cid;59 bool seqpacket_allow;60};61 62static u32 vhost_transport_get_local_cid(void)63{64 return VHOST_VSOCK_DEFAULT_HOST_CID;65}66 67/* Callers that dereference the return value must hold vhost_vsock_mutex or the68 * RCU read lock.69 */70static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)71{72 struct vhost_vsock *vsock;73 74 hash_for_each_possible_rcu(vhost_vsock_hash, vsock, hash, guest_cid) {75 u32 other_cid = vsock->guest_cid;76 77 /* Skip instances that have no CID yet */78 if (other_cid == 0)79 continue;80 81 if (other_cid == guest_cid)82 return vsock;83 84 }85 86 return NULL;87}88 89static void90vhost_transport_do_send_pkt(struct vhost_vsock *vsock,91 struct vhost_virtqueue *vq)92{93 struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];94 int pkts = 0, total_len = 0;95 bool added = false;96 bool restart_tx = false;97 98 mutex_lock(&vq->mutex);99 100 if (!vhost_vq_get_backend(vq))101 goto out;102 103 if (!vq_meta_prefetch(vq))104 goto out;105 106 /* Avoid further vmexits, we're already processing the virtqueue */107 vhost_disable_notify(&vsock->dev, vq);108 109 do {110 struct virtio_vsock_hdr *hdr;111 size_t iov_len, payload_len;112 struct iov_iter iov_iter;113 u32 flags_to_restore = 0;114 struct sk_buff *skb;115 unsigned out, in;116 size_t nbytes;117 u32 offset;118 int head;119 120 skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue);121 122 if (!skb) {123 vhost_enable_notify(&vsock->dev, vq);124 break;125 }126 127 head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),128 &out, &in, NULL, NULL);129 if (head < 0) {130 virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);131 break;132 }133 134 if (head == vq->num) {135 virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);136 /* We cannot finish yet if more buffers snuck in while137 * re-enabling notify.138 */139 if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {140 vhost_disable_notify(&vsock->dev, vq);141 continue;142 }143 break;144 }145 146 if (out) {147 kfree_skb(skb);148 vq_err(vq, "Expected 0 output buffers, got %u\n", out);149 break;150 }151 152 iov_len = iov_length(&vq->iov[out], in);153 if (iov_len < sizeof(*hdr)) {154 kfree_skb(skb);155 vq_err(vq, "Buffer len [%zu] too small\n", iov_len);156 break;157 }158 159 iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[out], in, iov_len);160 offset = VIRTIO_VSOCK_SKB_CB(skb)->offset;161 payload_len = skb->len - offset;162 hdr = virtio_vsock_hdr(skb);163 164 /* If the packet is greater than the space available in the165 * buffer, we split it using multiple buffers.166 */167 if (payload_len > iov_len - sizeof(*hdr)) {168 payload_len = iov_len - sizeof(*hdr);169 170 /* As we are copying pieces of large packet's buffer to171 * small rx buffers, headers of packets in rx queue are172 * created dynamically and are initialized with header173 * of current packet(except length). But in case of174 * SOCK_SEQPACKET, we also must clear message delimeter175 * bit (VIRTIO_VSOCK_SEQ_EOM) and MSG_EOR bit176 * (VIRTIO_VSOCK_SEQ_EOR) if set. Otherwise,177 * there will be sequence of packets with these178 * bits set. After initialized header will be copied to179 * rx buffer, these required bits will be restored.180 */181 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {182 hdr->flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);183 flags_to_restore |= VIRTIO_VSOCK_SEQ_EOM;184 185 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR) {186 hdr->flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);187 flags_to_restore |= VIRTIO_VSOCK_SEQ_EOR;188 }189 }190 }191 192 /* Set the correct length in the header */193 hdr->len = cpu_to_le32(payload_len);194 195 nbytes = copy_to_iter(hdr, sizeof(*hdr), &iov_iter);196 if (nbytes != sizeof(*hdr)) {197 kfree_skb(skb);198 vq_err(vq, "Faulted on copying pkt hdr\n");199 break;200 }201 202 if (skb_copy_datagram_iter(skb,203 offset,204 &iov_iter,205 payload_len)) {206 kfree_skb(skb);207 vq_err(vq, "Faulted on copying pkt buf\n");208 break;209 }210 211 /* Deliver to monitoring devices all packets that we212 * will transmit.213 */214 virtio_transport_deliver_tap_pkt(skb);215 216 vhost_add_used(vq, head, sizeof(*hdr) + payload_len);217 added = true;218 219 VIRTIO_VSOCK_SKB_CB(skb)->offset += payload_len;220 total_len += payload_len;221 222 /* If we didn't send all the payload we can requeue the packet223 * to send it with the next available buffer.224 */225 if (VIRTIO_VSOCK_SKB_CB(skb)->offset < skb->len) {226 hdr->flags |= cpu_to_le32(flags_to_restore);227 228 /* We are queueing the same skb to handle229 * the remaining bytes, and we want to deliver it230 * to monitoring devices in the next iteration.231 */232 virtio_vsock_skb_clear_tap_delivered(skb);233 virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);234 } else {235 if (virtio_vsock_skb_reply(skb)) {236 int val;237 238 val = atomic_dec_return(&vsock->queued_replies);239 240 /* Do we have resources to resume tx241 * processing?242 */243 if (val + 1 == tx_vq->num)244 restart_tx = true;245 }246 247 virtio_transport_consume_skb_sent(skb, true);248 }249 } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));250 if (added)251 vhost_signal(&vsock->dev, vq);252 253out:254 mutex_unlock(&vq->mutex);255 256 if (restart_tx)257 vhost_poll_queue(&tx_vq->poll);258}259 260static void vhost_transport_send_pkt_work(struct vhost_work *work)261{262 struct vhost_virtqueue *vq;263 struct vhost_vsock *vsock;264 265 vsock = container_of(work, struct vhost_vsock, send_pkt_work);266 vq = &vsock->vqs[VSOCK_VQ_RX];267 268 vhost_transport_do_send_pkt(vsock, vq);269}270 271static int272vhost_transport_send_pkt(struct sk_buff *skb)273{274 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);275 struct vhost_vsock *vsock;276 int len = skb->len;277 278 rcu_read_lock();279 280 /* Find the vhost_vsock according to guest context id */281 vsock = vhost_vsock_get(le64_to_cpu(hdr->dst_cid));282 if (!vsock) {283 rcu_read_unlock();284 kfree_skb(skb);285 return -ENODEV;286 }287 288 if (virtio_vsock_skb_reply(skb))289 atomic_inc(&vsock->queued_replies);290 291 virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);292 vhost_vq_work_queue(&vsock->vqs[VSOCK_VQ_RX], &vsock->send_pkt_work);293 294 rcu_read_unlock();295 return len;296}297 298static int299vhost_transport_cancel_pkt(struct vsock_sock *vsk)300{301 struct vhost_vsock *vsock;302 int cnt = 0;303 int ret = -ENODEV;304 305 rcu_read_lock();306 307 /* Find the vhost_vsock according to guest context id */308 vsock = vhost_vsock_get(vsk->remote_addr.svm_cid);309 if (!vsock)310 goto out;311 312 cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue);313 314 if (cnt) {315 struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];316 int new_cnt;317 318 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);319 if (new_cnt + cnt >= tx_vq->num && new_cnt < tx_vq->num)320 vhost_poll_queue(&tx_vq->poll);321 }322 323 ret = 0;324out:325 rcu_read_unlock();326 return ret;327}328 329static struct sk_buff *330vhost_vsock_alloc_skb(struct vhost_virtqueue *vq,331 unsigned int out, unsigned int in)332{333 struct virtio_vsock_hdr *hdr;334 struct iov_iter iov_iter;335 struct sk_buff *skb;336 size_t payload_len;337 size_t nbytes;338 size_t len;339 340 if (in != 0) {341 vq_err(vq, "Expected 0 input buffers, got %u\n", in);342 return NULL;343 }344 345 len = iov_length(vq->iov, out);346 347 /* len contains both payload and hdr */348 skb = virtio_vsock_alloc_skb(len, GFP_KERNEL);349 if (!skb)350 return NULL;351 352 iov_iter_init(&iov_iter, ITER_SOURCE, vq->iov, out, len);353 354 hdr = virtio_vsock_hdr(skb);355 nbytes = copy_from_iter(hdr, sizeof(*hdr), &iov_iter);356 if (nbytes != sizeof(*hdr)) {357 vq_err(vq, "Expected %zu bytes for pkt->hdr, got %zu bytes\n",358 sizeof(*hdr), nbytes);359 kfree_skb(skb);360 return NULL;361 }362 363 payload_len = le32_to_cpu(hdr->len);364 365 /* No payload */366 if (!payload_len)367 return skb;368 369 /* The pkt is too big or the length in the header is invalid */370 if (payload_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE ||371 payload_len + sizeof(*hdr) > len) {372 kfree_skb(skb);373 return NULL;374 }375 376 virtio_vsock_skb_rx_put(skb);377 378 nbytes = copy_from_iter(skb->data, payload_len, &iov_iter);379 if (nbytes != payload_len) {380 vq_err(vq, "Expected %zu byte payload, got %zu bytes\n",381 payload_len, nbytes);382 kfree_skb(skb);383 return NULL;384 }385 386 return skb;387}388 389/* Is there space left for replies to rx packets? */390static bool vhost_vsock_more_replies(struct vhost_vsock *vsock)391{392 struct vhost_virtqueue *vq = &vsock->vqs[VSOCK_VQ_TX];393 int val;394 395 smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */396 val = atomic_read(&vsock->queued_replies);397 398 return val < vq->num;399}400 401static bool vhost_transport_msgzerocopy_allow(void)402{403 return true;404}405 406static bool vhost_transport_seqpacket_allow(u32 remote_cid);407 408static struct virtio_transport vhost_transport = {409 .transport = {410 .module = THIS_MODULE,411 412 .get_local_cid = vhost_transport_get_local_cid,413 414 .init = virtio_transport_do_socket_init,415 .destruct = virtio_transport_destruct,416 .release = virtio_transport_release,417 .connect = virtio_transport_connect,418 .shutdown = virtio_transport_shutdown,419 .cancel_pkt = vhost_transport_cancel_pkt,420 421 .dgram_enqueue = virtio_transport_dgram_enqueue,422 .dgram_dequeue = virtio_transport_dgram_dequeue,423 .dgram_bind = virtio_transport_dgram_bind,424 .dgram_allow = virtio_transport_dgram_allow,425 426 .stream_enqueue = virtio_transport_stream_enqueue,427 .stream_dequeue = virtio_transport_stream_dequeue,428 .stream_has_data = virtio_transport_stream_has_data,429 .stream_has_space = virtio_transport_stream_has_space,430 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat,431 .stream_is_active = virtio_transport_stream_is_active,432 .stream_allow = virtio_transport_stream_allow,433 434 .seqpacket_dequeue = virtio_transport_seqpacket_dequeue,435 .seqpacket_enqueue = virtio_transport_seqpacket_enqueue,436 .seqpacket_allow = vhost_transport_seqpacket_allow,437 .seqpacket_has_data = virtio_transport_seqpacket_has_data,438 439 .msgzerocopy_allow = vhost_transport_msgzerocopy_allow,440 441 .notify_poll_in = virtio_transport_notify_poll_in,442 .notify_poll_out = virtio_transport_notify_poll_out,443 .notify_recv_init = virtio_transport_notify_recv_init,444 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block,445 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,446 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,447 .notify_send_init = virtio_transport_notify_send_init,448 .notify_send_pre_block = virtio_transport_notify_send_pre_block,449 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,450 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,451 .notify_buffer_size = virtio_transport_notify_buffer_size,452 .notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat,453 454 .unsent_bytes = virtio_transport_unsent_bytes,455 456 .read_skb = virtio_transport_read_skb,457 },458 459 .send_pkt = vhost_transport_send_pkt,460};461 462static bool vhost_transport_seqpacket_allow(u32 remote_cid)463{464 struct vhost_vsock *vsock;465 bool seqpacket_allow = false;466 467 rcu_read_lock();468 vsock = vhost_vsock_get(remote_cid);469 470 if (vsock)471 seqpacket_allow = vsock->seqpacket_allow;472 473 rcu_read_unlock();474 475 return seqpacket_allow;476}477 478static void vhost_vsock_handle_tx_kick(struct vhost_work *work)479{480 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,481 poll.work);482 struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,483 dev);484 int head, pkts = 0, total_len = 0;485 unsigned int out, in;486 struct sk_buff *skb;487 bool added = false;488 489 mutex_lock(&vq->mutex);490 491 if (!vhost_vq_get_backend(vq))492 goto out;493 494 if (!vq_meta_prefetch(vq))495 goto out;496 497 vhost_disable_notify(&vsock->dev, vq);498 do {499 struct virtio_vsock_hdr *hdr;500 501 if (!vhost_vsock_more_replies(vsock)) {502 /* Stop tx until the device processes already503 * pending replies. Leave tx virtqueue504 * callbacks disabled.505 */506 goto no_more_replies;507 }508 509 head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),510 &out, &in, NULL, NULL);511 if (head < 0)512 break;513 514 if (head == vq->num) {515 if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {516 vhost_disable_notify(&vsock->dev, vq);517 continue;518 }519 break;520 }521 522 skb = vhost_vsock_alloc_skb(vq, out, in);523 if (!skb) {524 vq_err(vq, "Faulted on pkt\n");525 continue;526 }527 528 total_len += sizeof(*hdr) + skb->len;529 530 /* Deliver to monitoring devices all received packets */531 virtio_transport_deliver_tap_pkt(skb);532 533 hdr = virtio_vsock_hdr(skb);534 535 /* Only accept correctly addressed packets */536 if (le64_to_cpu(hdr->src_cid) == vsock->guest_cid &&537 le64_to_cpu(hdr->dst_cid) ==538 vhost_transport_get_local_cid())539 virtio_transport_recv_pkt(&vhost_transport, skb);540 else541 kfree_skb(skb);542 543 vhost_add_used(vq, head, 0);544 added = true;545 } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));546 547no_more_replies:548 if (added)549 vhost_signal(&vsock->dev, vq);550 551out:552 mutex_unlock(&vq->mutex);553}554 555static void vhost_vsock_handle_rx_kick(struct vhost_work *work)556{557 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,558 poll.work);559 struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,560 dev);561 562 vhost_transport_do_send_pkt(vsock, vq);563}564 565static int vhost_vsock_start(struct vhost_vsock *vsock)566{567 struct vhost_virtqueue *vq;568 size_t i;569 int ret;570 571 mutex_lock(&vsock->dev.mutex);572 573 ret = vhost_dev_check_owner(&vsock->dev);574 if (ret)575 goto err;576 577 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {578 vq = &vsock->vqs[i];579 580 mutex_lock(&vq->mutex);581 582 if (!vhost_vq_access_ok(vq)) {583 ret = -EFAULT;584 goto err_vq;585 }586 587 if (!vhost_vq_get_backend(vq)) {588 vhost_vq_set_backend(vq, vsock);589 ret = vhost_vq_init_access(vq);590 if (ret)591 goto err_vq;592 }593 594 mutex_unlock(&vq->mutex);595 }596 597 /* Some packets may have been queued before the device was started,598 * let's kick the send worker to send them.599 */600 vhost_vq_work_queue(&vsock->vqs[VSOCK_VQ_RX], &vsock->send_pkt_work);601 602 mutex_unlock(&vsock->dev.mutex);603 return 0;604 605err_vq:606 vhost_vq_set_backend(vq, NULL);607 mutex_unlock(&vq->mutex);608 609 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {610 vq = &vsock->vqs[i];611 612 mutex_lock(&vq->mutex);613 vhost_vq_set_backend(vq, NULL);614 mutex_unlock(&vq->mutex);615 }616err:617 mutex_unlock(&vsock->dev.mutex);618 return ret;619}620 621static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner)622{623 size_t i;624 int ret = 0;625 626 mutex_lock(&vsock->dev.mutex);627 628 if (check_owner) {629 ret = vhost_dev_check_owner(&vsock->dev);630 if (ret)631 goto err;632 }633 634 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {635 struct vhost_virtqueue *vq = &vsock->vqs[i];636 637 mutex_lock(&vq->mutex);638 vhost_vq_set_backend(vq, NULL);639 mutex_unlock(&vq->mutex);640 }641 642err:643 mutex_unlock(&vsock->dev.mutex);644 return ret;645}646 647static void vhost_vsock_free(struct vhost_vsock *vsock)648{649 kvfree(vsock);650}651 652static int vhost_vsock_dev_open(struct inode *inode, struct file *file)653{654 struct vhost_virtqueue **vqs;655 struct vhost_vsock *vsock;656 int ret;657 658 /* This struct is large and allocation could fail, fall back to vmalloc659 * if there is no other way.660 */661 vsock = kvmalloc(sizeof(*vsock), GFP_KERNEL | __GFP_RETRY_MAYFAIL);662 if (!vsock)663 return -ENOMEM;664 665 vqs = kmalloc_array(ARRAY_SIZE(vsock->vqs), sizeof(*vqs), GFP_KERNEL);666 if (!vqs) {667 ret = -ENOMEM;668 goto out;669 }670 671 vsock->guest_cid = 0; /* no CID assigned yet */672 vsock->seqpacket_allow = false;673 674 atomic_set(&vsock->queued_replies, 0);675 676 vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX];677 vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX];678 vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;679 vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;680 681 vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs),682 UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT,683 VHOST_VSOCK_WEIGHT, true, NULL);684 685 file->private_data = vsock;686 skb_queue_head_init(&vsock->send_pkt_queue);687 vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work);688 return 0;689 690out:691 vhost_vsock_free(vsock);692 return ret;693}694 695static void vhost_vsock_flush(struct vhost_vsock *vsock)696{697 vhost_dev_flush(&vsock->dev);698}699 700static void vhost_vsock_reset_orphans(struct sock *sk)701{702 struct vsock_sock *vsk = vsock_sk(sk);703 704 /* vmci_transport.c doesn't take sk_lock here either. At least we're705 * under vsock_table_lock so the sock cannot disappear while we're706 * executing.707 */708 709 /* If the peer is still valid, no need to reset connection */710 if (vhost_vsock_get(vsk->remote_addr.svm_cid))711 return;712 713 /* If the close timeout is pending, let it expire. This avoids races714 * with the timeout callback.715 */716 if (vsk->close_work_scheduled)717 return;718 719 sock_set_flag(sk, SOCK_DONE);720 vsk->peer_shutdown = SHUTDOWN_MASK;721 sk->sk_state = SS_UNCONNECTED;722 sk->sk_err = ECONNRESET;723 sk_error_report(sk);724}725 726static int vhost_vsock_dev_release(struct inode *inode, struct file *file)727{728 struct vhost_vsock *vsock = file->private_data;729 730 mutex_lock(&vhost_vsock_mutex);731 if (vsock->guest_cid)732 hash_del_rcu(&vsock->hash);733 mutex_unlock(&vhost_vsock_mutex);734 735 /* Wait for other CPUs to finish using vsock */736 synchronize_rcu();737 738 /* Iterating over all connections for all CIDs to find orphans is739 * inefficient. Room for improvement here. */740 vsock_for_each_connected_socket(&vhost_transport.transport,741 vhost_vsock_reset_orphans);742 743 /* Don't check the owner, because we are in the release path, so we744 * need to stop the vsock device in any case.745 * vhost_vsock_stop() can not fail in this case, so we don't need to746 * check the return code.747 */748 vhost_vsock_stop(vsock, false);749 vhost_vsock_flush(vsock);750 vhost_dev_stop(&vsock->dev);751 752 virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue);753 754 vhost_dev_cleanup(&vsock->dev);755 kfree(vsock->dev.vqs);756 vhost_vsock_free(vsock);757 return 0;758}759 760static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid)761{762 struct vhost_vsock *other;763 764 /* Refuse reserved CIDs */765 if (guest_cid <= VMADDR_CID_HOST ||766 guest_cid == U32_MAX)767 return -EINVAL;768 769 /* 64-bit CIDs are not yet supported */770 if (guest_cid > U32_MAX)771 return -EINVAL;772 773 /* Refuse if CID is assigned to the guest->host transport (i.e. nested774 * VM), to make the loopback work.775 */776 if (vsock_find_cid(guest_cid))777 return -EADDRINUSE;778 779 /* Refuse if CID is already in use */780 mutex_lock(&vhost_vsock_mutex);781 other = vhost_vsock_get(guest_cid);782 if (other && other != vsock) {783 mutex_unlock(&vhost_vsock_mutex);784 return -EADDRINUSE;785 }786 787 if (vsock->guest_cid)788 hash_del_rcu(&vsock->hash);789 790 vsock->guest_cid = guest_cid;791 hash_add_rcu(vhost_vsock_hash, &vsock->hash, vsock->guest_cid);792 mutex_unlock(&vhost_vsock_mutex);793 794 return 0;795}796 797static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)798{799 struct vhost_virtqueue *vq;800 int i;801 802 if (features & ~VHOST_VSOCK_FEATURES)803 return -EOPNOTSUPP;804 805 mutex_lock(&vsock->dev.mutex);806 if ((features & (1 << VHOST_F_LOG_ALL)) &&807 !vhost_log_access_ok(&vsock->dev)) {808 goto err;809 }810 811 if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) {812 if (vhost_init_device_iotlb(&vsock->dev))813 goto err;814 }815 816 vsock->seqpacket_allow = features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET);817 818 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {819 vq = &vsock->vqs[i];820 mutex_lock(&vq->mutex);821 vq->acked_features = features;822 mutex_unlock(&vq->mutex);823 }824 mutex_unlock(&vsock->dev.mutex);825 return 0;826 827err:828 mutex_unlock(&vsock->dev.mutex);829 return -EFAULT;830}831 832static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl,833 unsigned long arg)834{835 struct vhost_vsock *vsock = f->private_data;836 void __user *argp = (void __user *)arg;837 u64 guest_cid;838 u64 features;839 int start;840 int r;841 842 switch (ioctl) {843 case VHOST_VSOCK_SET_GUEST_CID:844 if (copy_from_user(&guest_cid, argp, sizeof(guest_cid)))845 return -EFAULT;846 return vhost_vsock_set_cid(vsock, guest_cid);847 case VHOST_VSOCK_SET_RUNNING:848 if (copy_from_user(&start, argp, sizeof(start)))849 return -EFAULT;850 if (start)851 return vhost_vsock_start(vsock);852 else853 return vhost_vsock_stop(vsock, true);854 case VHOST_GET_FEATURES:855 features = VHOST_VSOCK_FEATURES;856 if (copy_to_user(argp, &features, sizeof(features)))857 return -EFAULT;858 return 0;859 case VHOST_SET_FEATURES:860 if (copy_from_user(&features, argp, sizeof(features)))861 return -EFAULT;862 return vhost_vsock_set_features(vsock, features);863 case VHOST_GET_BACKEND_FEATURES:864 features = VHOST_VSOCK_BACKEND_FEATURES;865 if (copy_to_user(argp, &features, sizeof(features)))866 return -EFAULT;867 return 0;868 case VHOST_SET_BACKEND_FEATURES:869 if (copy_from_user(&features, argp, sizeof(features)))870 return -EFAULT;871 if (features & ~VHOST_VSOCK_BACKEND_FEATURES)872 return -EOPNOTSUPP;873 vhost_set_backend_features(&vsock->dev, features);874 return 0;875 default:876 mutex_lock(&vsock->dev.mutex);877 r = vhost_dev_ioctl(&vsock->dev, ioctl, argp);878 if (r == -ENOIOCTLCMD)879 r = vhost_vring_ioctl(&vsock->dev, ioctl, argp);880 else881 vhost_vsock_flush(vsock);882 mutex_unlock(&vsock->dev.mutex);883 return r;884 }885}886 887static ssize_t vhost_vsock_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)888{889 struct file *file = iocb->ki_filp;890 struct vhost_vsock *vsock = file->private_data;891 struct vhost_dev *dev = &vsock->dev;892 int noblock = file->f_flags & O_NONBLOCK;893 894 return vhost_chr_read_iter(dev, to, noblock);895}896 897static ssize_t vhost_vsock_chr_write_iter(struct kiocb *iocb,898 struct iov_iter *from)899{900 struct file *file = iocb->ki_filp;901 struct vhost_vsock *vsock = file->private_data;902 struct vhost_dev *dev = &vsock->dev;903 904 return vhost_chr_write_iter(dev, from);905}906 907static __poll_t vhost_vsock_chr_poll(struct file *file, poll_table *wait)908{909 struct vhost_vsock *vsock = file->private_data;910 struct vhost_dev *dev = &vsock->dev;911 912 return vhost_chr_poll(file, dev, wait);913}914 915static const struct file_operations vhost_vsock_fops = {916 .owner = THIS_MODULE,917 .open = vhost_vsock_dev_open,918 .release = vhost_vsock_dev_release,919 .llseek = noop_llseek,920 .unlocked_ioctl = vhost_vsock_dev_ioctl,921 .compat_ioctl = compat_ptr_ioctl,922 .read_iter = vhost_vsock_chr_read_iter,923 .write_iter = vhost_vsock_chr_write_iter,924 .poll = vhost_vsock_chr_poll,925};926 927static struct miscdevice vhost_vsock_misc = {928 .minor = VHOST_VSOCK_MINOR,929 .name = "vhost-vsock",930 .fops = &vhost_vsock_fops,931};932 933static int __init vhost_vsock_init(void)934{935 int ret;936 937 ret = vsock_core_register(&vhost_transport.transport,938 VSOCK_TRANSPORT_F_H2G);939 if (ret < 0)940 return ret;941 942 ret = misc_register(&vhost_vsock_misc);943 if (ret) {944 vsock_core_unregister(&vhost_transport.transport);945 return ret;946 }947 948 return 0;949};950 951static void __exit vhost_vsock_exit(void)952{953 misc_deregister(&vhost_vsock_misc);954 vsock_core_unregister(&vhost_transport.transport);955};956 957module_init(vhost_vsock_init);958module_exit(vhost_vsock_exit);959MODULE_LICENSE("GPL v2");960MODULE_AUTHOR("Asias He");961MODULE_DESCRIPTION("vhost transport for vsock ");962MODULE_ALIAS_MISCDEV(VHOST_VSOCK_MINOR);963MODULE_ALIAS("devname:vhost-vsock");964