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Commit 0ea9e1d3 authored by Asias He's avatar Asias He Committed by Michael S. Tsirkin
Browse files

VSOCK: Introduce virtio_transport.ko 



VM sockets virtio transport implementation.  This driver runs in the
guest.

Signed-off-by: default avatarAsias He <asias@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 06a8fc78

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -12147,6 +12147,7 @@ S: Maintained 
F:	include/linux/virtio_vsock.h

F:	include/uapi/linux/virtio_vsock.h

F:	net/vmw_vsock/virtio_transport_common.c

F:	net/vmw_vsock/virtio_transport.c



VIRTUAL SERIO DEVICE DRIVER

M:	Stephen Chandler Paul <thatslyude@gmail.com>

net/vmw_vsock/virtio_transport.c

0 → 100644
+624 −0
Original line number Diff line number Diff line 
/*

 * virtio transport for vsock

 *

 * Copyright (C) 2013-2015 Red Hat, Inc.

 * Author: Asias He <asias@redhat.com>

 *         Stefan Hajnoczi <stefanha@redhat.com>

 *

 * Some of the code is take from Gerd Hoffmann <kraxel@redhat.com>'s

 * early virtio-vsock proof-of-concept bits.

 *

 * This work is licensed under the terms of the GNU GPL, version 2.

 */

#include <linux/spinlock.h>

#include <linux/module.h>

#include <linux/list.h>

#include <linux/atomic.h>

#include <linux/virtio.h>

#include <linux/virtio_ids.h>

#include <linux/virtio_config.h>

#include <linux/virtio_vsock.h>

#include <net/sock.h>

#include <linux/mutex.h>

#include <net/af_vsock.h>



static struct workqueue_struct *virtio_vsock_workqueue;

static struct virtio_vsock *the_virtio_vsock;

static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */



struct virtio_vsock {

	struct virtio_device *vdev;

	struct virtqueue *vqs[VSOCK_VQ_MAX];



	/* Virtqueue processing is deferred to a workqueue */

	struct work_struct tx_work;

	struct work_struct rx_work;

	struct work_struct event_work;



	/* The following fields are protected by tx_lock.  vqs[VSOCK_VQ_TX]

	 * must be accessed with tx_lock held.

	 */

	struct mutex tx_lock;



	struct work_struct send_pkt_work;

	spinlock_t send_pkt_list_lock;

	struct list_head send_pkt_list;



	atomic_t queued_replies;



	/* The following fields are protected by rx_lock.  vqs[VSOCK_VQ_RX]

	 * must be accessed with rx_lock held.

	 */

	struct mutex rx_lock;

	int rx_buf_nr;

	int rx_buf_max_nr;



	/* The following fields are protected by event_lock.

	 * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.

	 */

	struct mutex event_lock;

	struct virtio_vsock_event event_list[8];



	u32 guest_cid;

};



static struct virtio_vsock *virtio_vsock_get(void)

{

	return the_virtio_vsock;

}



static u32 virtio_transport_get_local_cid(void)

{

	struct virtio_vsock *vsock = virtio_vsock_get();



	return vsock->guest_cid;

}



static void

virtio_transport_send_pkt_work(struct work_struct *work)

{

	struct virtio_vsock *vsock =

		container_of(work, struct virtio_vsock, send_pkt_work);

	struct virtqueue *vq;

	bool added = false;

	bool restart_rx = false;



	mutex_lock(&vsock->tx_lock);



	vq = vsock->vqs[VSOCK_VQ_TX];



	/* Avoid unnecessary interrupts while we're processing the ring */

	virtqueue_disable_cb(vq);



	for (;;) {

		struct virtio_vsock_pkt *pkt;

		struct scatterlist hdr, buf, *sgs[2];

		int ret, in_sg = 0, out_sg = 0;

		bool reply;



		spin_lock_bh(&vsock->send_pkt_list_lock);

		if (list_empty(&vsock->send_pkt_list)) {

			spin_unlock_bh(&vsock->send_pkt_list_lock);

			virtqueue_enable_cb(vq);

			break;

		}



		pkt = list_first_entry(&vsock->send_pkt_list,

				       struct virtio_vsock_pkt, list);

		list_del_init(&pkt->list);

		spin_unlock_bh(&vsock->send_pkt_list_lock);



		reply = pkt->reply;



		sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));

		sgs[out_sg++] = &hdr;

		if (pkt->buf) {

			sg_init_one(&buf, pkt->buf, pkt->len);

			sgs[out_sg++] = &buf;

		}



		ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);

		if (ret < 0) {

			spin_lock_bh(&vsock->send_pkt_list_lock);

			list_add(&pkt->list, &vsock->send_pkt_list);

			spin_unlock_bh(&vsock->send_pkt_list_lock);



			if (!virtqueue_enable_cb(vq) && ret == -ENOSPC)

				continue; /* retry now that we have more space */

			break;

		}



		if (reply) {

			struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];

			int val;



			val = atomic_dec_return(&vsock->queued_replies);



			/* Do we now have resources to resume rx processing? */

			if (val + 1 == virtqueue_get_vring_size(rx_vq))

				restart_rx = true;

		}



		added = true;

	}



	if (added)

		virtqueue_kick(vq);



	mutex_unlock(&vsock->tx_lock);



	if (restart_rx)

		queue_work(virtio_vsock_workqueue, &vsock->rx_work);

}



static int

virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)

{

	struct virtio_vsock *vsock;

	int len = pkt->len;



	vsock = virtio_vsock_get();

	if (!vsock) {

		virtio_transport_free_pkt(pkt);

		return -ENODEV;

	}



	if (pkt->reply)

		atomic_inc(&vsock->queued_replies);



	spin_lock_bh(&vsock->send_pkt_list_lock);

	list_add_tail(&pkt->list, &vsock->send_pkt_list);

	spin_unlock_bh(&vsock->send_pkt_list_lock);



	queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);

	return len;

}



static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)

{

	int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;

	struct virtio_vsock_pkt *pkt;

	struct scatterlist hdr, buf, *sgs[2];

	struct virtqueue *vq;

	int ret;



	vq = vsock->vqs[VSOCK_VQ_RX];



	do {

		pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);

		if (!pkt)

			break;



		pkt->buf = kmalloc(buf_len, GFP_KERNEL);

		if (!pkt->buf) {

			virtio_transport_free_pkt(pkt);

			break;

		}



		pkt->len = buf_len;



		sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));

		sgs[0] = &hdr;



		sg_init_one(&buf, pkt->buf, buf_len);

		sgs[1] = &buf;

		ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);

		if (ret) {

			virtio_transport_free_pkt(pkt);

			break;

		}

		vsock->rx_buf_nr++;

	} while (vq->num_free);

	if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)

		vsock->rx_buf_max_nr = vsock->rx_buf_nr;

	virtqueue_kick(vq);

}



static void virtio_transport_tx_work(struct work_struct *work)

{

	struct virtio_vsock *vsock =

		container_of(work, struct virtio_vsock, tx_work);

	struct virtqueue *vq;

	bool added = false;



	vq = vsock->vqs[VSOCK_VQ_TX];

	mutex_lock(&vsock->tx_lock);

	do {

		struct virtio_vsock_pkt *pkt;

		unsigned int len;



		virtqueue_disable_cb(vq);

		while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {

			virtio_transport_free_pkt(pkt);

			added = true;

		}

	} while (!virtqueue_enable_cb(vq));

	mutex_unlock(&vsock->tx_lock);



	if (added)

		queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);

}



/* Is there space left for replies to rx packets? */

static bool virtio_transport_more_replies(struct virtio_vsock *vsock)

{

	struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];

	int val;



	smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */

	val = atomic_read(&vsock->queued_replies);



	return val < virtqueue_get_vring_size(vq);

}



static void virtio_transport_rx_work(struct work_struct *work)

{

	struct virtio_vsock *vsock =

		container_of(work, struct virtio_vsock, rx_work);

	struct virtqueue *vq;



	vq = vsock->vqs[VSOCK_VQ_RX];



	mutex_lock(&vsock->rx_lock);



	do {

		virtqueue_disable_cb(vq);

		for (;;) {

			struct virtio_vsock_pkt *pkt;

			unsigned int len;



			if (!virtio_transport_more_replies(vsock)) {

				/* Stop rx until the device processes already

				 * pending replies.  Leave rx virtqueue

				 * callbacks disabled.

				 */

				goto out;

			}



			pkt = virtqueue_get_buf(vq, &len);

			if (!pkt) {

				break;

			}



			vsock->rx_buf_nr--;



			/* Drop short/long packets */

			if (unlikely(len < sizeof(pkt->hdr) ||

				     len > sizeof(pkt->hdr) + pkt->len)) {

				virtio_transport_free_pkt(pkt);

				continue;

			}



			pkt->len = len - sizeof(pkt->hdr);

			virtio_transport_recv_pkt(pkt);

		}

	} while (!virtqueue_enable_cb(vq));



out:

	if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)

		virtio_vsock_rx_fill(vsock);

	mutex_unlock(&vsock->rx_lock);

}



/* event_lock must be held */

static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,

				       struct virtio_vsock_event *event)

{

	struct scatterlist sg;

	struct virtqueue *vq;



	vq = vsock->vqs[VSOCK_VQ_EVENT];



	sg_init_one(&sg, event, sizeof(*event));



	return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);

}



/* event_lock must be held */

static void virtio_vsock_event_fill(struct virtio_vsock *vsock)

{

	size_t i;



	for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {

		struct virtio_vsock_event *event = &vsock->event_list[i];



		virtio_vsock_event_fill_one(vsock, event);

	}



	virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);

}



static void virtio_vsock_reset_sock(struct sock *sk)

{

	lock_sock(sk);

	sk->sk_state = SS_UNCONNECTED;

	sk->sk_err = ECONNRESET;

	sk->sk_error_report(sk);

	release_sock(sk);

}



static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)

{

	struct virtio_device *vdev = vsock->vdev;

	u64 guest_cid;



	vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),

			  &guest_cid, sizeof(guest_cid));

	vsock->guest_cid = le64_to_cpu(guest_cid);

}



/* event_lock must be held */

static void virtio_vsock_event_handle(struct virtio_vsock *vsock,

				      struct virtio_vsock_event *event)

{

	switch (le32_to_cpu(event->id)) {

	case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:

		virtio_vsock_update_guest_cid(vsock);

		vsock_for_each_connected_socket(virtio_vsock_reset_sock);

		break;

	}

}



static void virtio_transport_event_work(struct work_struct *work)

{

	struct virtio_vsock *vsock =

		container_of(work, struct virtio_vsock, event_work);

	struct virtqueue *vq;



	vq = vsock->vqs[VSOCK_VQ_EVENT];



	mutex_lock(&vsock->event_lock);



	do {

		struct virtio_vsock_event *event;

		unsigned int len;



		virtqueue_disable_cb(vq);

		while ((event = virtqueue_get_buf(vq, &len)) != NULL) {

			if (len == sizeof(*event))

				virtio_vsock_event_handle(vsock, event);



			virtio_vsock_event_fill_one(vsock, event);

		}

	} while (!virtqueue_enable_cb(vq));



	virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);



	mutex_unlock(&vsock->event_lock);

}



static void virtio_vsock_event_done(struct virtqueue *vq)

{

	struct virtio_vsock *vsock = vq->vdev->priv;



	if (!vsock)

		return;

	queue_work(virtio_vsock_workqueue, &vsock->event_work);

}



static void virtio_vsock_tx_done(struct virtqueue *vq)

{

	struct virtio_vsock *vsock = vq->vdev->priv;



	if (!vsock)

		return;

	queue_work(virtio_vsock_workqueue, &vsock->tx_work);

}



static void virtio_vsock_rx_done(struct virtqueue *vq)

{

	struct virtio_vsock *vsock = vq->vdev->priv;



	if (!vsock)

		return;

	queue_work(virtio_vsock_workqueue, &vsock->rx_work);

}



static struct virtio_transport virtio_transport = {

	.transport = {

		.get_local_cid            = virtio_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,



		.dgram_bind               = virtio_transport_dgram_bind,

		.dgram_dequeue            = virtio_transport_dgram_dequeue,

		.dgram_enqueue            = virtio_transport_dgram_enqueue,

		.dgram_allow              = virtio_transport_dgram_allow,



		.stream_dequeue           = virtio_transport_stream_dequeue,

		.stream_enqueue           = virtio_transport_stream_enqueue,

		.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,



		.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,



		.set_buffer_size          = virtio_transport_set_buffer_size,

		.set_min_buffer_size      = virtio_transport_set_min_buffer_size,

		.set_max_buffer_size      = virtio_transport_set_max_buffer_size,

		.get_buffer_size          = virtio_transport_get_buffer_size,

		.get_min_buffer_size      = virtio_transport_get_min_buffer_size,

		.get_max_buffer_size      = virtio_transport_get_max_buffer_size,

	},



	.send_pkt = virtio_transport_send_pkt,

};



static int virtio_vsock_probe(struct virtio_device *vdev)

{

	vq_callback_t *callbacks[] = {

		virtio_vsock_rx_done,

		virtio_vsock_tx_done,

		virtio_vsock_event_done,

	};

	static const char * const names[] = {

		"rx",

		"tx",

		"event",

	};

	struct virtio_vsock *vsock = NULL;

	int ret;



	ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);

	if (ret)

		return ret;



	/* Only one virtio-vsock device per guest is supported */

	if (the_virtio_vsock) {

		ret = -EBUSY;

		goto out;

	}



	vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);

	if (!vsock) {

		ret = -ENOMEM;

		goto out;

	}



	vsock->vdev = vdev;



	ret = vsock->vdev->config->find_vqs(vsock->vdev, VSOCK_VQ_MAX,

					    vsock->vqs, callbacks, names);

	if (ret < 0)

		goto out;



	virtio_vsock_update_guest_cid(vsock);



	ret = vsock_core_init(&virtio_transport.transport);

	if (ret < 0)

		goto out_vqs;



	vsock->rx_buf_nr = 0;

	vsock->rx_buf_max_nr = 0;

	atomic_set(&vsock->queued_replies, 0);



	vdev->priv = vsock;

	the_virtio_vsock = vsock;

	mutex_init(&vsock->tx_lock);

	mutex_init(&vsock->rx_lock);

	mutex_init(&vsock->event_lock);

	spin_lock_init(&vsock->send_pkt_list_lock);

	INIT_LIST_HEAD(&vsock->send_pkt_list);

	INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);

	INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);

	INIT_WORK(&vsock->event_work, virtio_transport_event_work);

	INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);



	mutex_lock(&vsock->rx_lock);

	virtio_vsock_rx_fill(vsock);

	mutex_unlock(&vsock->rx_lock);



	mutex_lock(&vsock->event_lock);

	virtio_vsock_event_fill(vsock);

	mutex_unlock(&vsock->event_lock);



	mutex_unlock(&the_virtio_vsock_mutex);

	return 0;



out_vqs:

	vsock->vdev->config->del_vqs(vsock->vdev);

out:

	kfree(vsock);

	mutex_unlock(&the_virtio_vsock_mutex);

	return ret;

}



static void virtio_vsock_remove(struct virtio_device *vdev)

{

	struct virtio_vsock *vsock = vdev->priv;

	struct virtio_vsock_pkt *pkt;



	flush_work(&vsock->rx_work);

	flush_work(&vsock->tx_work);

	flush_work(&vsock->event_work);

	flush_work(&vsock->send_pkt_work);



	vdev->config->reset(vdev);



	mutex_lock(&vsock->rx_lock);

	while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))

		virtio_transport_free_pkt(pkt);

	mutex_unlock(&vsock->rx_lock);



	mutex_lock(&vsock->tx_lock);

	while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))

		virtio_transport_free_pkt(pkt);

	mutex_unlock(&vsock->tx_lock);



	spin_lock_bh(&vsock->send_pkt_list_lock);

	while (!list_empty(&vsock->send_pkt_list)) {

		pkt = list_first_entry(&vsock->send_pkt_list,

				       struct virtio_vsock_pkt, list);

		list_del(&pkt->list);

		virtio_transport_free_pkt(pkt);

	}

	spin_unlock_bh(&vsock->send_pkt_list_lock);



	mutex_lock(&the_virtio_vsock_mutex);

	the_virtio_vsock = NULL;

	vsock_core_exit();

	mutex_unlock(&the_virtio_vsock_mutex);



	vdev->config->del_vqs(vdev);



	kfree(vsock);

}



static struct virtio_device_id id_table[] = {

	{ VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },

	{ 0 },

};



static unsigned int features[] = {

};



static struct virtio_driver virtio_vsock_driver = {

	.feature_table = features,

	.feature_table_size = ARRAY_SIZE(features),

	.driver.name = KBUILD_MODNAME,

	.driver.owner = THIS_MODULE,

	.id_table = id_table,

	.probe = virtio_vsock_probe,

	.remove = virtio_vsock_remove,

};



static int __init virtio_vsock_init(void)

{

	int ret;



	virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);

	if (!virtio_vsock_workqueue)

		return -ENOMEM;

	ret = register_virtio_driver(&virtio_vsock_driver);

	if (ret)

		destroy_workqueue(virtio_vsock_workqueue);

	return ret;

}



static void __exit virtio_vsock_exit(void)

{

	unregister_virtio_driver(&virtio_vsock_driver);

	destroy_workqueue(virtio_vsock_workqueue);

}



module_init(virtio_vsock_init);

module_exit(virtio_vsock_exit);

MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Asias He");

MODULE_DESCRIPTION("virtio transport for vsock");

MODULE_DEVICE_TABLE(virtio, id_table);