VSOCK: Introduce virtio-vsock.ko (32e61b06) · Commits · e / devices / android_kernel_fairphone_FP3

net/vmw_vsock/virtio_transport.c

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+466 −0

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		/*
		* 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/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 */
		static void virtio_vsock_rx_fill(struct virtio_vsock *vsock);

		struct virtio_vsock {
		/* Virtio device */
		struct virtio_device *vdev;
		/* Virtio virtqueue */
		struct virtqueue *vqs[VSOCK_VQ_MAX];
		/* Wait queue for send pkt */
		wait_queue_head_t queue_wait;
		/* Work item to send pkt */
		struct work_struct tx_work;
		/* Work item to recv pkt */
		struct work_struct rx_work;
		/* Mutex to protect send pkt*/
		struct mutex tx_lock;
		/* Mutex to protect recv pkt*/
		struct mutex rx_lock;
		/* Number of recv buffers */
		int rx_buf_nr;
		/* Number of max recv buffers */
		int rx_buf_max_nr;
		/* Used for global tx buf limitation */
		u32 total_tx_buf;
		/* Guest context id, just like guest ip address */
		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 int
		virtio_transport_send_pkt(struct vsock_sock *vsk,
		struct virtio_vsock_pkt_info *info)
		{
		u32 src_cid, src_port, dst_cid, dst_port;
		int ret, in_sg = 0, out_sg = 0;
		struct virtio_transport *trans;
		struct virtio_vsock_pkt *pkt;
		struct virtio_vsock *vsock;
		struct scatterlist hdr, buf, *sgs[2];
		struct virtqueue *vq;
		u32 pkt_len = info->pkt_len;
		DEFINE_WAIT(wait);

		vsock = virtio_vsock_get();
		if (!vsock)
		return -ENODEV;

		src_cid = virtio_transport_get_local_cid();
		src_port = vsk->local_addr.svm_port;
		if (!info->remote_cid) {
		dst_cid = vsk->remote_addr.svm_cid;
		dst_port = vsk->remote_addr.svm_port;
		} else {
		dst_cid = info->remote_cid;
		dst_port = info->remote_port;
		}

		trans = vsk->trans;
		vq = vsock->vqs[VSOCK_VQ_TX];

		if (pkt_len > VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE)
		pkt_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
		pkt_len = virtio_transport_get_credit(trans, pkt_len);
		/* Do not send zero length OP_RW pkt*/
		if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
		return pkt_len;

		/* Respect global tx buf limitation */
		mutex_lock(&vsock->tx_lock);
		while (pkt_len + vsock->total_tx_buf > VIRTIO_VSOCK_MAX_TX_BUF_SIZE) {
		prepare_to_wait_exclusive(&vsock->queue_wait, &wait,
		TASK_UNINTERRUPTIBLE);
		mutex_unlock(&vsock->tx_lock);
		schedule();
		mutex_lock(&vsock->tx_lock);
		finish_wait(&vsock->queue_wait, &wait);
		}
		vsock->total_tx_buf += pkt_len;
		mutex_unlock(&vsock->tx_lock);

		pkt = virtio_transport_alloc_pkt(vsk, info, pkt_len,
		src_cid, src_port,
		dst_cid, dst_port);
		if (!pkt) {
		mutex_lock(&vsock->tx_lock);
		vsock->total_tx_buf -= pkt_len;
		mutex_unlock(&vsock->tx_lock);
		virtio_transport_put_credit(trans, pkt_len);
		return -ENOMEM;
		}

		pr_debug("%s:info->pkt_len= %d\n", __func__, info->pkt_len);

		/* Will be released in virtio_transport_send_pkt_work */
		sock_hold(&trans->vsk->sk);
		virtio_transport_inc_tx_pkt(pkt);

		/* Put pkt in the virtqueue */
		sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
		sgs[out_sg++] = &hdr;
		if (info->msg && info->pkt_len > 0) {
		sg_init_one(&buf, pkt->buf, pkt->len);
		sgs[out_sg++] = &buf;
		}

		mutex_lock(&vsock->tx_lock);
		while ((ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt,
		GFP_KERNEL)) < 0) {
		prepare_to_wait_exclusive(&vsock->queue_wait, &wait,
		TASK_UNINTERRUPTIBLE);
		mutex_unlock(&vsock->tx_lock);
		schedule();
		mutex_lock(&vsock->tx_lock);
		finish_wait(&vsock->queue_wait, &wait);
		}
		virtqueue_kick(vq);
		mutex_unlock(&vsock->tx_lock);

		return pkt_len;
		}

		static struct virtio_transport_pkt_ops virtio_ops = {
		.send_pkt = virtio_transport_send_pkt,
		};

		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) {
		pr_debug("%s: fail to allocate pkt\n", __func__);
		goto out;
		}

		/* TODO: use mergeable rx buffer */
		pkt->buf = kmalloc(buf_len, GFP_KERNEL);
		if (!pkt->buf) {
		pr_debug("%s: fail to allocate pkt->buf\n", __func__);
		goto err;
		}

		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)
		goto err;
		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;
		out:
		virtqueue_kick(vq);
		return;
		err:
		virtqueue_kick(vq);
		virtio_transport_free_pkt(pkt);
		return;
		}

		static void virtio_transport_send_pkt_work(struct work_struct *work)
		{
		struct virtio_vsock *vsock =
		container_of(work, struct virtio_vsock, tx_work);
		struct virtio_vsock_pkt *pkt;
		bool added = false;
		struct virtqueue *vq;
		unsigned int len;
		struct sock *sk;

		vq = vsock->vqs[VSOCK_VQ_TX];
		mutex_lock(&vsock->tx_lock);
		do {
		virtqueue_disable_cb(vq);
		while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
		sk = &pkt->trans->vsk->sk;
		virtio_transport_dec_tx_pkt(pkt);
		/* Release refcnt taken in virtio_transport_send_pkt */
		sock_put(sk);
		vsock->total_tx_buf -= pkt->len;
		virtio_transport_free_pkt(pkt);
		added = true;
		}
		} while (!virtqueue_enable_cb(vq));
		mutex_unlock(&vsock->tx_lock);

		if (added)
		wake_up(&vsock->queue_wait);
		}

		static void virtio_transport_recv_pkt_work(struct work_struct *work)
		{
		struct virtio_vsock *vsock =
		container_of(work, struct virtio_vsock, rx_work);
		struct virtio_vsock_pkt *pkt;
		struct virtqueue *vq;
		unsigned int len;

		vq = vsock->vqs[VSOCK_VQ_RX];
		mutex_lock(&vsock->rx_lock);
		do {
		virtqueue_disable_cb(vq);
		while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
		pkt->len = len;
		virtio_transport_recv_pkt(pkt);
		vsock->rx_buf_nr--;
		}
		} while (!virtqueue_enable_cb(vq));

		if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
		virtio_vsock_rx_fill(vsock);
		mutex_unlock(&vsock->rx_lock);
		}

		static void virtio_vsock_ctrl_done(struct virtqueue *vq)
		{
		}

		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 int
		virtio_transport_socket_init(struct vsock_sock vsk, struct vsock_sock psk)
		{
		struct virtio_transport *trans;
		int ret;

		ret = virtio_transport_do_socket_init(vsk, psk);
		if (ret)
		return ret;

		trans = vsk->trans;
		trans->ops = &virtio_ops;
		return ret;
		}

		static struct vsock_transport virtio_transport = {
		.get_local_cid = virtio_transport_get_local_cid,

		.init = virtio_transport_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,
		};

		static int virtio_vsock_probe(struct virtio_device *vdev)
		{
		vq_callback_t *callbacks[] = {
		virtio_vsock_ctrl_done,
		virtio_vsock_rx_done,
		virtio_vsock_tx_done,
		};
		const char *names[] = {
		"ctrl",
		"rx",
		"tx",
		};
		struct virtio_vsock *vsock = NULL;
		u32 guest_cid;
		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;

		vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
		&guest_cid, sizeof(guest_cid));
		vsock->guest_cid = le32_to_cpu(guest_cid);
		pr_debug("%s:guest_cid=%d\n", __func__, vsock->guest_cid);

		ret = vsock_core_init(&virtio_transport);
		if (ret < 0)
		goto out_vqs;

		vsock->rx_buf_nr = 0;
		vsock->rx_buf_max_nr = 0;

		vdev->priv = the_virtio_vsock = vsock;
		init_waitqueue_head(&vsock->queue_wait);
		mutex_init(&vsock->tx_lock);
		mutex_init(&vsock->rx_lock);
		INIT_WORK(&vsock->rx_work, virtio_transport_recv_pkt_work);
		INIT_WORK(&vsock->tx_work, virtio_transport_send_pkt_work);

		mutex_lock(&vsock->rx_lock);
		virtio_vsock_rx_fill(vsock);
		mutex_unlock(&vsock->rx_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;

		mutex_lock(&the_virtio_vsock_mutex);
		the_virtio_vsock = NULL;
		vsock_core_exit();
		mutex_unlock(&the_virtio_vsock_mutex);

		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);