| Message ID | 1605223150-10888-11-git-send-email-michael.christie@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vhost/qemu: thread per IO SCSI vq | expand |
On Thu, Nov 12, 2020 at 05:19:09PM -0600, Mike Christie wrote: > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 2f98b81..e953031 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1736,6 +1736,28 @@ static long vhost_vring_set_num_addr(struct vhost_dev *d, > > return r; > } > + > +static long vhost_vring_set_enable(struct vhost_dev *d, > + struct vhost_virtqueue *vq, > + void __user *argp) > +{ > + struct vhost_vring_state s; > + int ret = 0; > + > + if (vq->private_data) > + return -EBUSY; > + > + if (copy_from_user(&s, argp, sizeof s)) > + return -EFAULT; > + > + if (s.num != 1 && s.num != 0) > + return -EINVAL; > + > + if (d->ops && d->ops->enable_vring) > + ret = d->ops->enable_vring(vq, s.num); > + return ret; > +} Silently ignoring this ioctl on drivers that don't implement d->ops->enable_vring() could be a problem. Userspace expects to be able to enable/disable vqs, we can't just return 0 because the vq won't be enabled/disabled as requested. > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h > index a293f48..1279c09 100644 > --- a/drivers/vhost/vhost.h > +++ b/drivers/vhost/vhost.h > @@ -158,6 +158,7 @@ struct vhost_msg_node { > > struct vhost_dev_ops { > int (*msg_handler)(struct vhost_dev *dev, struct vhost_iotlb_msg *msg); > + int (*enable_vring)(struct vhost_virtqueue *vq, bool enable); Please add doc comments explaining what this callback needs to do and the environment in which it is executed (locks that are held, etc).
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 2f98b81..e953031 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1736,6 +1736,28 @@ static long vhost_vring_set_num_addr(struct vhost_dev *d, return r; } + +static long vhost_vring_set_enable(struct vhost_dev *d, + struct vhost_virtqueue *vq, + void __user *argp) +{ + struct vhost_vring_state s; + int ret = 0; + + if (vq->private_data) + return -EBUSY; + + if (copy_from_user(&s, argp, sizeof s)) + return -EFAULT; + + if (s.num != 1 && s.num != 0) + return -EINVAL; + + if (d->ops && d->ops->enable_vring) + ret = d->ops->enable_vring(vq, s.num); + return ret; +} + long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) { struct file *eventfp, *filep = NULL; @@ -1765,6 +1787,9 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg mutex_lock(&vq->mutex); switch (ioctl) { + case VHOST_SET_VRING_ENABLE: + r = vhost_vring_set_enable(d, vq, argp); + break; case VHOST_SET_VRING_BASE: /* Moving base with an active backend? * You don't want to do that. */ diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index a293f48..1279c09 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -158,6 +158,7 @@ struct vhost_msg_node { struct vhost_dev_ops { int (*msg_handler)(struct vhost_dev *dev, struct vhost_iotlb_msg *msg); + int (*enable_vring)(struct vhost_virtqueue *vq, bool enable); }; struct vhost_dev { diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index c998860..3ffd133 100644 --- a/include/uapi/linux/vhost.h +++ b/include/uapi/linux/vhost.h @@ -70,6 +70,7 @@ #define VHOST_VRING_BIG_ENDIAN 1 #define VHOST_SET_VRING_ENDIAN _IOW(VHOST_VIRTIO, 0x13, struct vhost_vring_state) #define VHOST_GET_VRING_ENDIAN _IOW(VHOST_VIRTIO, 0x14, struct vhost_vring_state) +#define VHOST_SET_VRING_ENABLE _IOW(VHOST_VIRTIO, 0x15, struct vhost_vring_state) /* The following ioctls use eventfd file descriptors to signal and poll * for events. */
This adds a new ioctl VHOST_SET_VRING_ENABLE that the vhost drivers can implement a callout for and execute an operation when the vq is enabled/disabled. Signed-off-by: Mike Christie <michael.christie@oracle.com> --- drivers/vhost/vhost.c | 25 +++++++++++++++++++++++++ drivers/vhost/vhost.h | 1 + include/uapi/linux/vhost.h | 1 + 3 files changed, 27 insertions(+)