On Thu, Jun 27, 2013 at 01:42:46PM +0300, Michael S. Tsirkin wrote:
> On Thu, Jun 27, 2013 at 04:00:03PM +0800, Asias He wrote:
> > VM sockets vhost transport implementation. This module runs in host
> > kernel.
> >
> > Signed-off-by: Asias He <as...@redhat.com>
>
> Has any thought been given to how this affects migration?
> I don't see any API for an application to
> move to a different host and reconnect to a running
> vsock in guest.
>
> I think we could merge without this, there are more
> pressing issues, but it's probably a requirement
> if you want this to replace e.g. serial in many
> scenarious.
I do not plan to support migration for the initial merge as well.
Reconnection is one issue needs to be addressed. Another issue is that if
the destination host is running vhost-vsock already, the port might be
used already. We probably need namesapce support.
> > ---
> > 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 <as...@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"
>
> Send patch to move this to include/linux ?
Okay. Will cook a patch.
> > +#include "vhost.h"
> > +#include "vsock.h"
> > +
> > +#define VHOST_VSOCK_DEFAULT_HOST_CID 2;
>
> Sure you want that ; there? This can result in strange code, e.g.
>
> int a = VHOST_VSOCK_DEFAULT_HOST_CID + 1;
> set's a to 2.
Fixed.
> > +
> > +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. */
>
> typo
Fixed.
> > +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;
> > +}
> > +
>
> Interesting. So all hosts in fact have the same CID?
Yes. Andy commented on this already.
> > +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 */
>
> Pls fix. memcpy_from_iovec is not harder.
Do we have this helper?
> > + 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);
>
> I think you should not signal if used was not updated.
Right, it is very easy to add the optimization here.
> > + 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();
>
> interestingly this is the only place cid
> is used. Shouldn't we validate it?
The local cid is a constant, how can we valicate it?
> > + 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);
>
> Confused. There's a single socket per dst cid?
No, each guest has a cid, each guest has a struct vhost_vsock instance,
dst_cid tells us which struct vhost_vsock instance to use for this
packet.
> > + 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;
>
> Is there support for non stream sockets?
> Without credits, you get all kind of nasty
> starvation issues.
We support SOCK_STREAM and SOCK_DGRAM. The credit thing is used for
SOCK_STREAM right now. I can extend it to SOCK_DGRAM as well.
> > + }
> > + 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);
>
> We also need global limit on amount of memory per
> socket. Even if remote is OK with getting 20G from us,
> we might not have so much kernel memory.
Yes, we need global limit.
> > + 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)
>
> No SET without GET please.
But the GET is useless here. We know the guest cid in userspace already.
> > +#endif
> > --
> > 1.8.1.4
--
Asias
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