Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 948 insertions, 0 deletions

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
new file mode 100644
index 000000000..1f3b89c88
--- /dev/null
+++ b/drivers/vhost/vsock.c
@@ -0,0 +1,948 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * vhost transport for vsock
+ *
+ * Copyright (C) 2013-2015 Red Hat, Inc.
+ * Author: Asias He <asias@redhat.com>
+ *         Stefan Hajnoczi <stefanha@redhat.com>
+ */
+#include <linux/miscdevice.h>
+#include <linux/atomic.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/vmalloc.h>
+#include <net/sock.h>
+#include <linux/virtio_vsock.h>
+#include <linux/vhost.h>
+#include <linux/hashtable.h>
+
+#include <net/af_vsock.h>
+#include "vhost.h"
+
+#define VHOST_VSOCK_DEFAULT_HOST_CID	2
+/* Max number of bytes transferred before requeueing the job.
+ * Using this limit prevents one virtqueue from starving others. */
+#define VHOST_VSOCK_WEIGHT 0x80000
+/* Max number of packets transferred before requeueing the job.
+ * Using this limit prevents one virtqueue from starving others with
+ * small pkts.
+ */
+#define VHOST_VSOCK_PKT_WEIGHT 256
+
+enum {
+	VHOST_VSOCK_FEATURES = VHOST_FEATURES |
+			       (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
+			       (1ULL << VIRTIO_VSOCK_F_SEQPACKET)
+};
+
+enum {
+	VHOST_VSOCK_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
+};
+
+/* Used to track all the vhost_vsock instances on the system. */
+static DEFINE_MUTEX(vhost_vsock_mutex);
+static DEFINE_READ_MOSTLY_HASHTABLE(vhost_vsock_hash, 8);
+
+struct vhost_vsock {
+	struct vhost_dev dev;
+	struct vhost_virtqueue vqs[2];
+
+	/* Link to global vhost_vsock_hash, writes use vhost_vsock_mutex */
+	struct hlist_node hash;
+
+	struct vhost_work send_pkt_work;
+	struct sk_buff_head send_pkt_queue; /* host->guest pending packets */
+
+	atomic_t queued_replies;
+
+	u32 guest_cid;
+	bool seqpacket_allow;
+};
+
+static u32 vhost_transport_get_local_cid(void)
+{
+	return VHOST_VSOCK_DEFAULT_HOST_CID;
+}
+
+/* Callers that dereference the return value must hold vhost_vsock_mutex or the
+ * RCU read lock.
+ */
+static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
+{
+	struct vhost_vsock *vsock;
+
+	hash_for_each_possible_rcu(vhost_vsock_hash, vsock, hash, guest_cid) {
+		u32 other_cid = vsock->guest_cid;
+
+		/* Skip instances that have no CID yet */
+		if (other_cid == 0)
+			continue;
+
+		if (other_cid == guest_cid)
+			return vsock;
+
+	}
+
+	return NULL;
+}
+
+static void
+vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
+			    struct vhost_virtqueue *vq)
+{
+	struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
+	int pkts = 0, total_len = 0;
+	bool added = false;
+	bool restart_tx = false;
+
+	mutex_lock(&vq->mutex);
+
+	if (!vhost_vq_get_backend(vq))
+		goto out;
+
+	if (!vq_meta_prefetch(vq))
+		goto out;
+
+	/* Avoid further vmexits, we're already processing the virtqueue */
+	vhost_disable_notify(&vsock->dev, vq);
+
+	do {
+		struct virtio_vsock_hdr *hdr;
+		size_t iov_len, payload_len;
+		struct iov_iter iov_iter;
+		u32 flags_to_restore = 0;
+		struct sk_buff *skb;
+		unsigned out, in;
+		size_t nbytes;
+		int head;
+
+		skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue);
+
+		if (!skb) {
+			vhost_enable_notify(&vsock->dev, vq);
+			break;
+		}
+
+		head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
+					 &out, &in, NULL, NULL);
+		if (head < 0) {
+			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
+			break;
+		}
+
+		if (head == vq->num) {
+			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
+			/* We cannot finish yet if more buffers snuck in while
+			 * re-enabling notify.
+			 */
+			if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
+				vhost_disable_notify(&vsock->dev, vq);
+				continue;
+			}
+			break;
+		}
+
+		if (out) {
+			kfree_skb(skb);
+			vq_err(vq, "Expected 0 output buffers, got %u\n", out);
+			break;
+		}
+
+		iov_len = iov_length(&vq->iov[out], in);
+		if (iov_len < sizeof(*hdr)) {
+			kfree_skb(skb);
+			vq_err(vq, "Buffer len [%zu] too small\n", iov_len);
+			break;
+		}
+
+		iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[out], in, iov_len);
+		payload_len = skb->len;
+		hdr = virtio_vsock_hdr(skb);
+
+		/* If the packet is greater than the space available in the
+		 * buffer, we split it using multiple buffers.
+		 */
+		if (payload_len > iov_len - sizeof(*hdr)) {
+			payload_len = iov_len - sizeof(*hdr);
+
+			/* As we are copying pieces of large packet's buffer to
+			 * small rx buffers, headers of packets in rx queue are
+			 * created dynamically and are initialized with header
+			 * of current packet(except length). But in case of
+			 * SOCK_SEQPACKET, we also must clear message delimeter
+			 * bit (VIRTIO_VSOCK_SEQ_EOM) and MSG_EOR bit
+			 * (VIRTIO_VSOCK_SEQ_EOR) if set. Otherwise,
+			 * there will be sequence of packets with these
+			 * bits set. After initialized header will be copied to
+			 * rx buffer, these required bits will be restored.
+			 */
+			if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
+				hdr->flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
+				flags_to_restore |= VIRTIO_VSOCK_SEQ_EOM;
+
+				if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR) {
+					hdr->flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
+					flags_to_restore |= VIRTIO_VSOCK_SEQ_EOR;
+				}
+			}
+		}
+
+		/* Set the correct length in the header */
+		hdr->len = cpu_to_le32(payload_len);
+
+		nbytes = copy_to_iter(hdr, sizeof(*hdr), &iov_iter);
+		if (nbytes != sizeof(*hdr)) {
+			kfree_skb(skb);
+			vq_err(vq, "Faulted on copying pkt hdr\n");
+			break;
+		}
+
+		nbytes = copy_to_iter(skb->data, payload_len, &iov_iter);
+		if (nbytes != payload_len) {
+			kfree_skb(skb);
+			vq_err(vq, "Faulted on copying pkt buf\n");
+			break;
+		}
+
+		/* Deliver to monitoring devices all packets that we
+		 * will transmit.
+		 */
+		virtio_transport_deliver_tap_pkt(skb);
+
+		vhost_add_used(vq, head, sizeof(*hdr) + payload_len);
+		added = true;
+
+		skb_pull(skb, payload_len);
+		total_len += payload_len;
+
+		/* If we didn't send all the payload we can requeue the packet
+		 * to send it with the next available buffer.
+		 */
+		if (skb->len > 0) {
+			hdr->flags |= cpu_to_le32(flags_to_restore);
+
+			/* We are queueing the same skb to handle
+			 * the remaining bytes, and we want to deliver it
+			 * to monitoring devices in the next iteration.
+			 */
+			virtio_vsock_skb_clear_tap_delivered(skb);
+			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
+		} else {
+			if (virtio_vsock_skb_reply(skb)) {
+				int val;
+
+				val = atomic_dec_return(&vsock->queued_replies);
+
+				/* Do we have resources to resume tx
+				 * processing?
+				 */
+				if (val + 1 == tx_vq->num)
+					restart_tx = true;
+			}
+
+			consume_skb(skb);
+		}
+	} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
+	if (added)
+		vhost_signal(&vsock->dev, vq);
+
+out:
+	mutex_unlock(&vq->mutex);
+
+	if (restart_tx)
+		vhost_poll_queue(&tx_vq->poll);
+}
+
+static void vhost_transport_send_pkt_work(struct vhost_work *work)
+{
+	struct vhost_virtqueue *vq;
+	struct vhost_vsock *vsock;
+
+	vsock = container_of(work, struct vhost_vsock, send_pkt_work);
+	vq = &vsock->vqs[VSOCK_VQ_RX];
+
+	vhost_transport_do_send_pkt(vsock, vq);
+}
+
+static int
+vhost_transport_send_pkt(struct sk_buff *skb)
+{
+	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
+	struct vhost_vsock *vsock;
+	int len = skb->len;
+
+	rcu_read_lock();
+
+	/* Find the vhost_vsock according to guest context id  */
+	vsock = vhost_vsock_get(le64_to_cpu(hdr->dst_cid));
+	if (!vsock) {
+		rcu_read_unlock();
+		kfree_skb(skb);
+		return -ENODEV;
+	}
+
+	if (virtio_vsock_skb_reply(skb))
+		atomic_inc(&vsock->queued_replies);
+
+	virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);
+	vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
+
+	rcu_read_unlock();
+	return len;
+}
+
+static int
+vhost_transport_cancel_pkt(struct vsock_sock *vsk)
+{
+	struct vhost_vsock *vsock;
+	int cnt = 0;
+	int ret = -ENODEV;
+
+	rcu_read_lock();
+
+	/* Find the vhost_vsock according to guest context id  */
+	vsock = vhost_vsock_get(vsk->remote_addr.svm_cid);
+	if (!vsock)
+		goto out;
+
+	cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue);
+
+	if (cnt) {
+		struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
+		int new_cnt;
+
+		new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
+		if (new_cnt + cnt >= tx_vq->num && new_cnt < tx_vq->num)
+			vhost_poll_queue(&tx_vq->poll);
+	}
+
+	ret = 0;
+out:
+	rcu_read_unlock();
+	return ret;
+}
+
+static struct sk_buff *
+vhost_vsock_alloc_skb(struct vhost_virtqueue *vq,
+		      unsigned int out, unsigned int in)
+{
+	struct virtio_vsock_hdr *hdr;
+	struct iov_iter iov_iter;
+	struct sk_buff *skb;
+	size_t payload_len;
+	size_t nbytes;
+	size_t len;
+
+	if (in != 0) {
+		vq_err(vq, "Expected 0 input buffers, got %u\n", in);
+		return NULL;
+	}
+
+	len = iov_length(vq->iov, out);
+
+	/* len contains both payload and hdr */
+	skb = virtio_vsock_alloc_skb(len, GFP_KERNEL);
+	if (!skb)
+		return NULL;
+
+	iov_iter_init(&iov_iter, ITER_SOURCE, vq->iov, out, len);
+
+	hdr = virtio_vsock_hdr(skb);
+	nbytes = copy_from_iter(hdr, sizeof(*hdr), &iov_iter);
+	if (nbytes != sizeof(*hdr)) {
+		vq_err(vq, "Expected %zu bytes for pkt->hdr, got %zu bytes\n",
+		       sizeof(*hdr), nbytes);
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	payload_len = le32_to_cpu(hdr->len);
+
+	/* No payload */
+	if (!payload_len)
+		return skb;
+
+	/* The pkt is too big or the length in the header is invalid */
+	if (payload_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE ||
+	    payload_len + sizeof(*hdr) > len) {
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	virtio_vsock_skb_rx_put(skb);
+
+	nbytes = copy_from_iter(skb->data, payload_len, &iov_iter);
+	if (nbytes != payload_len) {
+		vq_err(vq, "Expected %zu byte payload, got %zu bytes\n",
+		       payload_len, nbytes);
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	return skb;
+}
+
+/* Is there space left for replies to rx packets? */
+static bool vhost_vsock_more_replies(struct vhost_vsock *vsock)
+{
+	struct vhost_virtqueue *vq = &vsock->vqs[VSOCK_VQ_TX];
+	int val;
+
+	smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
+	val = atomic_read(&vsock->queued_replies);
+
+	return val < vq->num;
+}
+
+static bool vhost_transport_seqpacket_allow(u32 remote_cid);
+
+static struct virtio_transport vhost_transport = {
+	.transport = {
+		.module                   = THIS_MODULE,
+
+		.get_local_cid            = vhost_transport_get_local_cid,
+
+		.init                     = virtio_transport_do_socket_init,
+		.destruct                 = virtio_transport_destruct,
+		.release                  = virtio_transport_release,
+		.connect                  = virtio_transport_connect,
+		.shutdown                 = virtio_transport_shutdown,
+		.cancel_pkt               = vhost_transport_cancel_pkt,
+
+		.dgram_enqueue            = virtio_transport_dgram_enqueue,
+		.dgram_dequeue            = virtio_transport_dgram_dequeue,
+		.dgram_bind               = virtio_transport_dgram_bind,
+		.dgram_allow              = virtio_transport_dgram_allow,
+
+		.stream_enqueue           = virtio_transport_stream_enqueue,
+		.stream_dequeue           = virtio_transport_stream_dequeue,
+		.stream_has_data          = virtio_transport_stream_has_data,
+		.stream_has_space         = virtio_transport_stream_has_space,
+		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
+		.stream_is_active         = virtio_transport_stream_is_active,
+		.stream_allow             = virtio_transport_stream_allow,
+
+		.seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,
+		.seqpacket_enqueue        = virtio_transport_seqpacket_enqueue,
+		.seqpacket_allow          = vhost_transport_seqpacket_allow,
+		.seqpacket_has_data       = virtio_transport_seqpacket_has_data,
+
+		.notify_poll_in           = virtio_transport_notify_poll_in,
+		.notify_poll_out          = virtio_transport_notify_poll_out,
+		.notify_recv_init         = virtio_transport_notify_recv_init,
+		.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
+		.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
+		.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
+		.notify_send_init         = virtio_transport_notify_send_init,
+		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
+		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
+		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
+		.notify_buffer_size       = virtio_transport_notify_buffer_size,
+
+	},
+
+	.send_pkt = vhost_transport_send_pkt,
+};
+
+static bool vhost_transport_seqpacket_allow(u32 remote_cid)
+{
+	struct vhost_vsock *vsock;
+	bool seqpacket_allow = false;
+
+	rcu_read_lock();
+	vsock = vhost_vsock_get(remote_cid);
+
+	if (vsock)
+		seqpacket_allow = vsock->seqpacket_allow;
+
+	rcu_read_unlock();
+
+	return seqpacket_allow;
+}
+
+static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
+{
+	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
+						  poll.work);
+	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
+						 dev);
+	int head, pkts = 0, total_len = 0;
+	unsigned int out, in;
+	struct sk_buff *skb;
+	bool added = false;
+
+	mutex_lock(&vq->mutex);
+
+	if (!vhost_vq_get_backend(vq))
+		goto out;
+
+	if (!vq_meta_prefetch(vq))
+		goto out;
+
+	vhost_disable_notify(&vsock->dev, vq);
+	do {
+		struct virtio_vsock_hdr *hdr;
+
+		if (!vhost_vsock_more_replies(vsock)) {
+			/* Stop tx until the device processes already
+			 * pending replies.  Leave tx virtqueue
+			 * callbacks disabled.
+			 */
+			goto no_more_replies;
+		}
+
+		head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
+					 &out, &in, NULL, NULL);
+		if (head < 0)
+			break;
+
+		if (head == vq->num) {
+			if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
+				vhost_disable_notify(&vsock->dev, vq);
+				continue;
+			}
+			break;
+		}
+
+		skb = vhost_vsock_alloc_skb(vq, out, in);
+		if (!skb) {
+			vq_err(vq, "Faulted on pkt\n");
+			continue;
+		}
+
+		total_len += sizeof(*hdr) + skb->len;
+
+		/* Deliver to monitoring devices all received packets */
+		virtio_transport_deliver_tap_pkt(skb);
+
+		hdr = virtio_vsock_hdr(skb);
+
+		/* Only accept correctly addressed packets */
+		if (le64_to_cpu(hdr->src_cid) == vsock->guest_cid &&
+		    le64_to_cpu(hdr->dst_cid) ==
+		    vhost_transport_get_local_cid())
+			virtio_transport_recv_pkt(&vhost_transport, skb);
+		else
+			kfree_skb(skb);
+
+		vhost_add_used(vq, head, 0);
+		added = true;
+	} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
+
+no_more_replies:
+	if (added)
+		vhost_signal(&vsock->dev, vq);
+
+out:
+	mutex_unlock(&vq->mutex);
+}
+
+static void vhost_vsock_handle_rx_kick(struct vhost_work *work)
+{
+	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
+						poll.work);
+	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
+						 dev);
+
+	vhost_transport_do_send_pkt(vsock, vq);
+}
+
+static int vhost_vsock_start(struct vhost_vsock *vsock)
+{
+	struct vhost_virtqueue *vq;
+	size_t i;
+	int ret;
+
+	mutex_lock(&vsock->dev.mutex);
+
+	ret = vhost_dev_check_owner(&vsock->dev);
+	if (ret)
+		goto err;
+
+	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
+		vq = &vsock->vqs[i];
+
+		mutex_lock(&vq->mutex);
+
+		if (!vhost_vq_access_ok(vq)) {
+			ret = -EFAULT;
+			goto err_vq;
+		}
+
+		if (!vhost_vq_get_backend(vq)) {
+			vhost_vq_set_backend(vq, vsock);
+			ret = vhost_vq_init_access(vq);
+			if (ret)
+				goto err_vq;
+		}
+
+		mutex_unlock(&vq->mutex);
+	}
+
+	/* Some packets may have been queued before the device was started,
+	 * let's kick the send worker to send them.
+	 */
+	vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
+
+	mutex_unlock(&vsock->dev.mutex);
+	return 0;
+
+err_vq:
+	vhost_vq_set_backend(vq, NULL);
+	mutex_unlock(&vq->mutex);
+
+	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
+		vq = &vsock->vqs[i];
+
+		mutex_lock(&vq->mutex);
+		vhost_vq_set_backend(vq, NULL);
+		mutex_unlock(&vq->mutex);
+	}
+err:
+	mutex_unlock(&vsock->dev.mutex);
+	return ret;
+}
+
+static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner)
+{
+	size_t i;
+	int ret = 0;
+
+	mutex_lock(&vsock->dev.mutex);
+
+	if (check_owner) {
+		ret = vhost_dev_check_owner(&vsock->dev);
+		if (ret)
+			goto err;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
+		struct vhost_virtqueue *vq = &vsock->vqs[i];
+
+		mutex_lock(&vq->mutex);
+		vhost_vq_set_backend(vq, NULL);
+		mutex_unlock(&vq->mutex);
+	}
+
+err:
+	mutex_unlock(&vsock->dev.mutex);
+	return ret;
+}
+
+static void vhost_vsock_free(struct vhost_vsock *vsock)
+{
+	kvfree(vsock);
+}
+
+static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
+{
+	struct vhost_virtqueue **vqs;
+	struct vhost_vsock *vsock;
+	int ret;
+
+	/* This struct is large and allocation could fail, fall back to vmalloc
+	 * if there is no other way.
+	 */
+	vsock = kvmalloc(sizeof(*vsock), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
+	if (!vsock)
+		return -ENOMEM;
+
+	vqs = kmalloc_array(ARRAY_SIZE(vsock->vqs), sizeof(*vqs), GFP_KERNEL);
+	if (!vqs) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	vsock->guest_cid = 0; /* no CID assigned yet */
+
+	atomic_set(&vsock->queued_replies, 0);
+
+	vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX];
+	vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX];
+	vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
+	vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
+
+	vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs),
+		       UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT,
+		       VHOST_VSOCK_WEIGHT, true, NULL);
+
+	file->private_data = vsock;
+	skb_queue_head_init(&vsock->send_pkt_queue);
+	vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work);
+	return 0;
+
+out:
+	vhost_vsock_free(vsock);
+	return ret;
+}
+
+static void vhost_vsock_flush(struct vhost_vsock *vsock)
+{
+	vhost_dev_flush(&vsock->dev);
+}
+
+static void vhost_vsock_reset_orphans(struct sock *sk)
+{
+	struct vsock_sock *vsk = vsock_sk(sk);
+
+	/* vmci_transport.c doesn't take sk_lock here either.  At least we're
+	 * under vsock_table_lock so the sock cannot disappear while we're
+	 * executing.
+	 */
+
+	/* If the peer is still valid, no need to reset connection */
+	if (vhost_vsock_get(vsk->remote_addr.svm_cid))
+		return;
+
+	/* If the close timeout is pending, let it expire.  This avoids races
+	 * with the timeout callback.
+	 */
+	if (vsk->close_work_scheduled)
+		return;
+
+	sock_set_flag(sk, SOCK_DONE);
+	vsk->peer_shutdown = SHUTDOWN_MASK;
+	sk->sk_state = SS_UNCONNECTED;
+	sk->sk_err = ECONNRESET;
+	sk_error_report(sk);
+}
+
+static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
+{
+	struct vhost_vsock *vsock = file->private_data;
+
+	mutex_lock(&vhost_vsock_mutex);
+	if (vsock->guest_cid)
+		hash_del_rcu(&vsock->hash);
+	mutex_unlock(&vhost_vsock_mutex);
+
+	/* Wait for other CPUs to finish using vsock */
+	synchronize_rcu();
+
+	/* Iterating over all connections for all CIDs to find orphans is
+	 * inefficient.  Room for improvement here. */
+	vsock_for_each_connected_socket(&vhost_transport.transport,
+					vhost_vsock_reset_orphans);
+
+	/* Don't check the owner, because we are in the release path, so we
+	 * need to stop the vsock device in any case.
+	 * vhost_vsock_stop() can not fail in this case, so we don't need to
+	 * check the return code.
+	 */
+	vhost_vsock_stop(vsock, false);
+	vhost_vsock_flush(vsock);
+	vhost_dev_stop(&vsock->dev);
+
+	virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue);
+
+	vhost_dev_cleanup(&vsock->dev);
+	kfree(vsock->dev.vqs);
+	vhost_vsock_free(vsock);
+	return 0;
+}
+
+static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid)
+{
+	struct vhost_vsock *other;
+
+	/* Refuse reserved CIDs */
+	if (guest_cid <= VMADDR_CID_HOST ||
+	    guest_cid == U32_MAX)
+		return -EINVAL;
+
+	/* 64-bit CIDs are not yet supported */
+	if (guest_cid > U32_MAX)
+		return -EINVAL;
+
+	/* Refuse if CID is assigned to the guest->host transport (i.e. nested
+	 * VM), to make the loopback work.
+	 */
+	if (vsock_find_cid(guest_cid))
+		return -EADDRINUSE;
+
+	/* Refuse if CID is already in use */
+	mutex_lock(&vhost_vsock_mutex);
+	other = vhost_vsock_get(guest_cid);
+	if (other && other != vsock) {
+		mutex_unlock(&vhost_vsock_mutex);
+		return -EADDRINUSE;
+	}
+
+	if (vsock->guest_cid)
+		hash_del_rcu(&vsock->hash);
+
+	vsock->guest_cid = guest_cid;
+	hash_add_rcu(vhost_vsock_hash, &vsock->hash, vsock->guest_cid);
+	mutex_unlock(&vhost_vsock_mutex);
+
+	return 0;
+}
+
+static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)
+{
+	struct vhost_virtqueue *vq;
+	int i;
+
+	if (features & ~VHOST_VSOCK_FEATURES)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&vsock->dev.mutex);
+	if ((features & (1 << VHOST_F_LOG_ALL)) &&
+	    !vhost_log_access_ok(&vsock->dev)) {
+		goto err;
+	}
+
+	if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) {
+		if (vhost_init_device_iotlb(&vsock->dev, true))
+			goto err;
+	}
+
+	if (features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET))
+		vsock->seqpacket_allow = true;
+
+	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
+		vq = &vsock->vqs[i];
+		mutex_lock(&vq->mutex);
+		vq->acked_features = features;
+		mutex_unlock(&vq->mutex);
+	}
+	mutex_unlock(&vsock->dev.mutex);
+	return 0;
+
+err:
+	mutex_unlock(&vsock->dev.mutex);
+	return -EFAULT;
+}
+
+static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl,
+				  unsigned long arg)
+{
+	struct vhost_vsock *vsock = f->private_data;
+	void __user *argp = (void __user *)arg;
+	u64 guest_cid;
+	u64 features;
+	int start;
+	int r;
+
+	switch (ioctl) {
+	case VHOST_VSOCK_SET_GUEST_CID:
+		if (copy_from_user(&guest_cid, argp, sizeof(guest_cid)))
+			return -EFAULT;
+		return vhost_vsock_set_cid(vsock, guest_cid);
+	case VHOST_VSOCK_SET_RUNNING:
+		if (copy_from_user(&start, argp, sizeof(start)))
+			return -EFAULT;
+		if (start)
+			return vhost_vsock_start(vsock);
+		else
+			return vhost_vsock_stop(vsock, true);
+	case VHOST_GET_FEATURES:
+		features = VHOST_VSOCK_FEATURES;
+		if (copy_to_user(argp, &features, sizeof(features)))
+			return -EFAULT;
+		return 0;
+	case VHOST_SET_FEATURES:
+		if (copy_from_user(&features, argp, sizeof(features)))
+			return -EFAULT;
+		return vhost_vsock_set_features(vsock, features);
+	case VHOST_GET_BACKEND_FEATURES:
+		features = VHOST_VSOCK_BACKEND_FEATURES;
+		if (copy_to_user(argp, &features, sizeof(features)))
+			return -EFAULT;
+		return 0;
+	case VHOST_SET_BACKEND_FEATURES:
+		if (copy_from_user(&features, argp, sizeof(features)))
+			return -EFAULT;
+		if (features & ~VHOST_VSOCK_BACKEND_FEATURES)
+			return -EOPNOTSUPP;
+		vhost_set_backend_features(&vsock->dev, features);
+		return 0;
+	default:
+		mutex_lock(&vsock->dev.mutex);
+		r = vhost_dev_ioctl(&vsock->dev, ioctl, argp);
+		if (r == -ENOIOCTLCMD)
+			r = vhost_vring_ioctl(&vsock->dev, ioctl, argp);
+		else
+			vhost_vsock_flush(vsock);
+		mutex_unlock(&vsock->dev.mutex);
+		return r;
+	}
+}
+
+static ssize_t vhost_vsock_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *file = iocb->ki_filp;
+	struct vhost_vsock *vsock = file->private_data;
+	struct vhost_dev *dev = &vsock->dev;
+	int noblock = file->f_flags & O_NONBLOCK;
+
+	return vhost_chr_read_iter(dev, to, noblock);
+}
+
+static ssize_t vhost_vsock_chr_write_iter(struct kiocb *iocb,
+					struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct vhost_vsock *vsock = file->private_data;
+	struct vhost_dev *dev = &vsock->dev;
+
+	return vhost_chr_write_iter(dev, from);
+}
+
+static __poll_t vhost_vsock_chr_poll(struct file *file, poll_table *wait)
+{
+	struct vhost_vsock *vsock = file->private_data;
+	struct vhost_dev *dev = &vsock->dev;
+
+	return vhost_chr_poll(file, dev, wait);
+}
+
+static const struct file_operations vhost_vsock_fops = {
+	.owner          = THIS_MODULE,
+	.open           = vhost_vsock_dev_open,
+	.release        = vhost_vsock_dev_release,
+	.llseek		= noop_llseek,
+	.unlocked_ioctl = vhost_vsock_dev_ioctl,
+	.compat_ioctl   = compat_ptr_ioctl,
+	.read_iter      = vhost_vsock_chr_read_iter,
+	.write_iter     = vhost_vsock_chr_write_iter,
+	.poll           = vhost_vsock_chr_poll,
+};
+
+static struct miscdevice vhost_vsock_misc = {
+	.minor = VHOST_VSOCK_MINOR,
+	.name = "vhost-vsock",
+	.fops = &vhost_vsock_fops,
+};
+
+static int __init vhost_vsock_init(void)
+{
+	int ret;
+
+	ret = vsock_core_register(&vhost_transport.transport,
+				  VSOCK_TRANSPORT_F_H2G);
+	if (ret < 0)
+		return ret;
+
+	ret = misc_register(&vhost_vsock_misc);
+	if (ret) {
+		vsock_core_unregister(&vhost_transport.transport);
+		return ret;
+	}
+
+	return 0;
+};
+
+static void __exit vhost_vsock_exit(void)
+{
+	misc_deregister(&vhost_vsock_misc);
+	vsock_core_unregister(&vhost_transport.transport);
+};
+
+module_init(vhost_vsock_init);
+module_exit(vhost_vsock_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Asias He");
+MODULE_DESCRIPTION("vhost transport for vsock ");
+MODULE_ALIAS_MISCDEV(VHOST_VSOCK_MINOR);
+MODULE_ALIAS("devname:vhost-vsock");