Re: [RFC PATCH 1/6] vdpa: add bind_mm callback

[Jason Wang]

On Thu, Dec 15, 2022 at 12:30 AM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote:
>
> This new optional callback is used to bind the device to a specific
> address space so the vDPA framework can use VA when this callback
> is implemented.
>
> Suggested-by: Jason Wang <jasowang@xxxxxxxxxx>
> Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
> ---
>  include/linux/vdpa.h | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index 6d0f5e4e82c2..34388e21ef3f 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -282,6 +282,12 @@ struct vdpa_map_file {
>   *                             @iova: iova to be unmapped
>   *                             @size: size of the area
>   *                             Returns integer: success (0) or error (< 0)
> + * @bind_mm:                   Bind the device to a specific address space
> + *                             so the vDPA framework can use VA when this
> + *                             callback is implemented. (optional)
> + *                             @vdev: vdpa device
> + *                             @mm: address space to bind

Do we need an unbind or did a NULL mm mean unbind?

> + *                             @owner: process that owns the address space

Any reason we need the task_struct here?

Thanks

>   * @free:                      Free resources that belongs to vDPA (optional)
>   *                             @vdev: vdpa device
>   */
> @@ -341,6 +347,8 @@ struct vdpa_config_ops {
>                          u64 iova, u64 size);
>         int (*set_group_asid)(struct vdpa_device *vdev, unsigned int group,
>                               unsigned int asid);
> +       int (*bind_mm)(struct vdpa_device *vdev, struct mm_struct *mm,
> +                      struct task_struct *owner);
>
>         /* Free device resources */
>         void (*free)(struct vdpa_device *vdev);
> --
> 2.38.1
>