Re: [PATCH vhost v4 07/15] vdpa: Block vq address change in DRIVER_OK unless device supports it

Eugenio Perez Martin
2023-12-20T16:31:42Z

On Tue, Dec 19, 2023 at 7:09 PM Dragos Tatulea <dtatulea@nvidia.com> wrote:
>
> Virtqueue address change during DRIVE_OK is not supported by the virtio
> standard. Allow this op in DRIVER_OK only for devices that support
> changing the address during DRIVER_OK if the device is suspended.
>
> Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
> Suggested-by: Eugenio Pérez <eperezma@redhat.com>

Acked-by: Eugenio Pérez <eperezma@redhat.com>

> ---
> drivers/vhost/vdpa.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 00b4fa8e89f2..6bfa3391935a 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -625,6 +625,29 @@ static long vhost_vdpa_resume(struct vhost_vdpa *v)
> return ret;
> }
>
> +static bool vhost_vdpa_vq_config_allowed(struct vhost_vdpa *v, unsigned int cmd)
> +{
> + struct vdpa_device *vdpa = v->vdpa;
> + const struct vdpa_config_ops *ops = vdpa->config;
> + int feature;
> +
> + if (!(ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK))
> + return true;
> +
> + if (!v->suspended)
> + return false;
> +
> + switch (cmd) {
> + case VHOST_SET_VRING_ADDR:
> + feature = VHOST_BACKEND_F_CHANGEABLE_VQ_ADDR_IN_SUSPEND;
> + break;
> + default:
> + return false;
> + }
> +
> + return v->vdev.vqs && vhost_backend_has_feature(v->vdev.vqs[0], feature);
> +}
> +
> static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
> void __user *argp)
> {
> @@ -703,6 +726,9 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
>
> switch (cmd) {
> case VHOST_SET_VRING_ADDR:
> + if (!vhost_vdpa_vq_config_allowed(v, cmd))
> + return -EOPNOTSUPP;
> +
> if (ops->set_vq_address(vdpa, idx,
> (u64)(uintptr_t)vq->desc,
> (u64)(uintptr_t)vq->avail,
> --
> 2.43.0
>