[RFC 4/5] VSOCK: Introduce vhost-vsock.ko

[Asias He <asias@redhat.com>]

VM sockets vhost transport implementation. This module runs in host
kernel.

Signed-off-by: Asias He <asias@redhat.com>
---
 drivers/vhost/vsock.c | 534 ++++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/vhost/vsock.h |   4 +
 2 files changed, 538 insertions(+)
 create mode 100644 drivers/vhost/vsock.c
 create mode 100644 drivers/vhost/vsock.h

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
new file mode 100644
index 0000000..cb54090
--- /dev/null
+++ b/drivers/vhost/vsock.c
@@ -0,0 +1,534 @@
+/*
+ * vhost transport for vsock
+ *
+ * Copyright (C) 2013 Red Hat, Inc.
+ * Author: Asias He <asias@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <net/sock.h>
+#include <linux/virtio_vsock.h>
+#include <linux/vhost.h>
+
+#include "../../../net/vmw_vsock/af_vsock.h"
+#include "vhost.h"
+#include "vsock.h"
+
+#define VHOST_VSOCK_DEFAULT_HOST_CID	2;
+
+static int vhost_transport_socket_init(struct vsock_sock *vsk,
+				       struct vsock_sock *psk);
+
+enum {
+	VHOST_VSOCK_FEATURES = VHOST_FEATURES,
+};
+
+/* Used to track all the vhost_vsock instacne on the system. */
+static LIST_HEAD(vhost_vsock_list);
+static DEFINE_MUTEX(vhost_vsock_mutex);
+
+struct vhost_vsock_virtqueue {
+	struct vhost_virtqueue vq;
+};
+
+struct vhost_vsock {
+	/* Vhost device */
+	struct vhost_dev dev;
+	/* Vhost vsock virtqueue*/
+	struct vhost_vsock_virtqueue vqs[VSOCK_VQ_MAX];
+	/* Link to global vhost_vsock_list*/
+	struct list_head list;
+	/* Head for pkt from host to guest */
+	struct list_head send_pkt_list;
+	/* Work item to send pkt */
+	struct vhost_work send_pkt_work;
+	/* Guest contex id this vhost_vsock instance handles */
+	u32 guest_cid;
+};
+
+static u32 vhost_transport_get_local_cid(void)
+{
+	u32 cid = VHOST_VSOCK_DEFAULT_HOST_CID;
+	return cid;
+}
+
+static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
+{
+	struct vhost_vsock *vsock;
+
+	mutex_lock(&vhost_vsock_mutex);
+	list_for_each_entry(vsock, &vhost_vsock_list, list) {
+		if (vsock->guest_cid == guest_cid) {
+			mutex_unlock(&vhost_vsock_mutex);
+			return vsock;
+		}
+	}
+	mutex_unlock(&vhost_vsock_mutex);
+
+	return NULL;
+}
+
+static void
+vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
+			    struct vhost_virtqueue *vq)
+{
+	struct virtio_vsock_pkt *pkt;
+	unsigned out, in;
+	struct sock *sk;
+	int head, ret;
+
+	mutex_lock(&vq->mutex);
+	vhost_disable_notify(&vsock->dev, vq);
+	for (;;) {
+		if (list_empty(&vsock->send_pkt_list)) {
+			vhost_enable_notify(&vsock->dev, vq);
+			break;
+		}
+
+		head = vhost_get_vq_desc(&vsock->dev, vq, vq->iov,
+					ARRAY_SIZE(vq->iov), &out, &in,
+					NULL, NULL);
+		pr_debug("%s: head = %d\n", __func__, head);
+		if (head < 0)
+			break;
+
+		if (head == vq->num) {
+			if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
+				vhost_disable_notify(&vsock->dev, vq);
+				continue;
+			}
+			break;
+		}
+
+		pkt = list_first_entry(&vsock->send_pkt_list,
+				       struct virtio_vsock_pkt, list);
+		list_del_init(&pkt->list);
+
+		/* FIXME: no assumption of frame layout */
+		ret = __copy_to_user(vq->iov[0].iov_base, &pkt->hdr,
+				     sizeof(pkt->hdr));
+		if (ret) {
+			virtio_transport_free_pkt(pkt);
+			vq_err(vq, "Faulted on copying pkt hdr\n");
+			break;
+		}
+		if (pkt->buf && pkt->len > 0) {
+			ret = __copy_to_user(vq->iov[1].iov_base, pkt->buf,
+					    pkt->len);
+			if (ret) {
+				virtio_transport_free_pkt(pkt);
+				vq_err(vq, "Faulted on copying pkt buf\n");
+				break;
+			}
+		}
+
+		vhost_add_used(vq, head, pkt->len);
+
+		virtio_transport_dec_tx_pkt(pkt);
+
+		sk = sk_vsock(pkt->trans->vsk);
+		/* Release refcnt taken in vhost_transport_send_pkt */
+		sock_put(sk);
+
+		virtio_transport_free_pkt(pkt);
+	}
+	vhost_signal(&vsock->dev, vq);
+	mutex_unlock(&vq->mutex);
+}
+
+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].vq;
+
+	vhost_transport_do_send_pkt(vsock, vq);
+}
+
+static int
+vhost_transport_send_pkt(struct vsock_sock *vsk,
+			 struct virtio_vsock_pkt_info *info)
+{
+	u32 src_cid, src_port, dst_cid, dst_port;
+	struct virtio_transport *trans;
+	struct virtio_vsock_pkt *pkt;
+	struct vhost_virtqueue *vq;
+	struct vhost_vsock *vsock;
+	u64 credit;
+
+	src_cid = vhost_transport_get_local_cid();
+	src_port = vsk->local_addr.svm_port;
+	dst_cid = vsk->remote_addr.svm_cid;
+	dst_port = vsk->remote_addr.svm_port;
+
+	/* Find the vhost_vsock according to guest context id  */
+	vsock = vhost_vsock_get(dst_cid);
+	if (!vsock)
+		return -ENODEV;
+
+	trans = vsk->trans;
+	vq = &vsock->vqs[VSOCK_VQ_RX].vq;
+
+	if (info->type == SOCK_STREAM) {
+		credit = virtio_transport_get_credit(trans);
+		if (info->len > credit)
+			info->len = credit;
+	}
+	if (info->len > VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE)
+		info->len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+	/* Do not send zero length OP_RW pkt*/
+	if (info->len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
+		return info->len;
+
+	pkt = virtio_transport_alloc_pkt(vsk, info, info->len,
+					 src_cid, src_port,
+					 dst_cid, dst_port);
+	if (!pkt)
+		return -ENOMEM;
+
+	pr_debug("%s:info->len= %d\n", __func__, info->len);
+	/* Released in vhost_transport_do_send_pkt */
+	sock_hold(&trans->vsk->sk);
+	virtio_transport_inc_tx_pkt(pkt);
+
+	/* queue it up in vhost work */
+	mutex_lock(&vq->mutex);
+	list_add_tail(&pkt->list, &vsock->send_pkt_list);
+	vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
+	mutex_unlock(&vq->mutex);
+
+	return info->len;
+}
+
+static struct virtio_transport_pkt_ops vhost_ops = {
+	.send_pkt = vhost_transport_send_pkt,
+};
+
+static struct virtio_vsock_pkt *
+vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq)
+{
+	struct virtio_vsock_pkt *pkt;
+	int ret;
+	int len;
+
+	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+	if (!pkt)
+		return NULL;
+
+	len = sizeof(pkt->hdr);
+	if (unlikely(vq->iov[0].iov_len != len)) {
+		vq_err(vq, "Expecting pkt->hdr = %d, got %zu bytes\n",
+		       len, vq->iov[0].iov_len);
+		kfree(pkt);
+		return NULL;
+	}
+	ret = __copy_from_user(&pkt->hdr, vq->iov[0].iov_base, len);
+	if (ret) {
+		vq_err(vq, "Faulted on virtio_vsock_hdr\n");
+		kfree(pkt);
+		return NULL;
+	}
+
+	pkt->len = pkt->hdr.len;
+	pkt->off = 0;
+
+	/* No payload */
+	if (!pkt->len)
+		return pkt;
+
+	/* The pkt is too big */
+	if (pkt->len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
+		kfree(pkt);
+		return NULL;
+	}
+
+	pkt->buf = kmalloc(pkt->len, GFP_KERNEL);
+	if (!pkt->buf) {
+		kfree(pkt);
+		return NULL;
+	}
+
+	ret = __copy_from_user(pkt->buf, vq->iov[1].iov_base, pkt->len);
+	if (ret) {
+		vq_err(vq, "Faulted on virtio_vsock_hdr\n");
+		virtio_transport_free_pkt(pkt);
+	}
+
+	return pkt;
+}
+
+static void vhost_vsock_handle_ctl_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);
+
+	pr_debug("%s vq=%p, vsock=%p\n", __func__, vq, vsock);
+}
+
+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);
+	struct virtio_vsock_pkt *pkt;
+	int head, out, in;
+	u32 len;
+
+	mutex_lock(&vq->mutex);
+	vhost_disable_notify(&vsock->dev, vq);
+	for (;;) {
+		head = vhost_get_vq_desc(&vsock->dev, 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;
+		}
+
+		pkt = vhost_vsock_alloc_pkt(vq);
+		if (!pkt) {
+			vq_err(vq, "Faulted on pkt\n");
+			continue;
+		}
+
+		len = pkt->len;
+		virtio_transport_recv_pkt(pkt);
+		vhost_add_used(vq, head, len);
+	}
+	vhost_signal(&vsock->dev, vq);
+	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_dev_open(struct inode *inode, struct file *file)
+{
+	struct vhost_virtqueue **vqs;
+	struct vhost_vsock *vsock;
+	int ret;
+
+	vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
+	if (!vsock)
+		return -ENOMEM;
+
+	pr_debug("%s:vsock=%p\n", __func__, vsock);
+
+	vqs = kmalloc(VSOCK_VQ_MAX * sizeof(*vqs), GFP_KERNEL);
+	if (!vqs) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	vqs[VSOCK_VQ_CTRL] = &vsock->vqs[VSOCK_VQ_CTRL].vq;
+	vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX].vq;
+	vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX].vq;
+	vsock->vqs[VSOCK_VQ_CTRL].vq.handle_kick = vhost_vsock_handle_ctl_kick;
+	vsock->vqs[VSOCK_VQ_TX].vq.handle_kick = vhost_vsock_handle_tx_kick;
+	vsock->vqs[VSOCK_VQ_RX].vq.handle_kick = vhost_vsock_handle_rx_kick;
+
+	ret = vhost_dev_init(&vsock->dev, vqs, VSOCK_VQ_MAX);
+	if (ret < 0)
+		goto out_vqs;
+
+	file->private_data = vsock;
+	INIT_LIST_HEAD(&vsock->send_pkt_list);
+	vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work);
+
+	mutex_lock(&vhost_vsock_mutex);
+	list_add_tail(&vsock->list, &vhost_vsock_list);
+	mutex_unlock(&vhost_vsock_mutex);
+	return ret;
+
+out_vqs:
+	kfree(vqs);
+out:
+	kfree(vsock);
+	return ret;
+}
+
+static void vhost_vsock_flush(struct vhost_vsock *vsock)
+{
+	int i;
+
+	for (i = 0; i < VSOCK_VQ_MAX; i++)
+		vhost_poll_flush(&vsock->vqs[i].vq.poll);
+	vhost_work_flush(&vsock->dev, &vsock->send_pkt_work);
+}
+
+static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
+{
+	struct vhost_vsock *vsock = file->private_data;
+
+	mutex_lock(&vhost_vsock_mutex);
+	list_del(&vsock->list);
+	mutex_unlock(&vhost_vsock_mutex);
+
+	vhost_dev_stop(&vsock->dev);
+	vhost_vsock_flush(vsock);
+	vhost_dev_cleanup(&vsock->dev, false);
+	kfree(vsock->dev.vqs);
+	kfree(vsock);
+	return 0;
+}
+
+static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u32 guest_cid)
+{
+	mutex_lock(&vhost_vsock_mutex);
+	vsock->guest_cid = guest_cid;
+	pr_debug("%s:guest_cid=%d\n", __func__, guest_cid);
+	mutex_unlock(&vhost_vsock_mutex);
+
+	return 0;
+}
+
+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 __user *featurep = argp;
+	u32 __user *cidp = argp;
+	u32 guest_cid;
+	u64 features;
+	int r;
+
+	switch (ioctl) {
+	case VHOST_VSOCK_SET_GUEST_CID:
+		if (get_user(guest_cid, cidp))
+			return -EFAULT;
+		return vhost_vsock_set_cid(vsock, guest_cid);
+	case VHOST_GET_FEATURES:
+		features = VHOST_VSOCK_FEATURES;
+		if (copy_to_user(featurep, &features, sizeof(features)))
+			return -EFAULT;
+		return 0;
+	case VHOST_SET_FEATURES:
+		if (copy_from_user(&features, featurep, sizeof(features)))
+			return -EFAULT;
+		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 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,
+};
+
+static struct miscdevice vhost_vsock_misc = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "vhost-vsock",
+	.fops = &vhost_vsock_fops,
+};
+
+static int
+vhost_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 = &vhost_ops;
+
+	return ret;
+}
+
+static struct vsock_transport vhost_transport = {
+	.get_local_cid            = vhost_transport_get_local_cid,
+
+	.init                     = vhost_transport_socket_init,
+	.destruct                 = virtio_transport_destruct,
+	.release                  = virtio_transport_release,
+	.connect                  = virtio_transport_connect,
+	.shutdown                 = virtio_transport_shutdown,
+
+	.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,
+
+	.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 __init vhost_vsock_init(void)
+{
+	int ret;
+
+	ret = vsock_core_init(&vhost_transport);
+	if (ret < 0)
+		return ret;
+	return misc_register(&vhost_vsock_misc);
+};
+
+static void __exit vhost_vsock_exit(void)
+{
+	misc_deregister(&vhost_vsock_misc);
+	vsock_core_exit();
+};
+
+module_init(vhost_vsock_init);
+module_exit(vhost_vsock_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Asias He");
+MODULE_DESCRIPTION("vhost transport for vsock ");
diff --git a/drivers/vhost/vsock.h b/drivers/vhost/vsock.h
new file mode 100644
index 0000000..0ddb107
--- /dev/null
+++ b/drivers/vhost/vsock.h
@@ -0,0 +1,4 @@
+#ifndef VHOST_VSOCK_H
+#define VHOST_VSOCK_H
+#define VHOST_VSOCK_SET_GUEST_CID _IOW(VHOST_VIRTIO, 0x60, __u32)
+#endif
-- 
1.8.1.4