Re: [RFC 1/6] vduse: add v1 API definition

[Jason Wang]

On Fri, Jun 6, 2025 at 7:50 PM Eugenio Pérez <eperezma@xxxxxxxxxx> wrote:
>
> This allows to define all functions checking the API version set by the
> userland device.
>
> Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx>

It might be worth clarifying how it works.

For example,

1) would VDUSE behave differently or if it's just some new ioctls
2) If VDUSE behave differently, do we need a ioctl to set the API
version for backward compatibility?
3) If it means a brunch of new ioctls, could userspace just probe the
new ioctls instead?

Thanks

> ---
>  include/uapi/linux/vduse.h | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> index 68a627d04afa..9a56d0416bfe 100644
> --- a/include/uapi/linux/vduse.h
> +++ b/include/uapi/linux/vduse.h
> @@ -10,6 +10,10 @@
>
>  #define VDUSE_API_VERSION      0
>
> +/* VQ groups and ASID support */
> +
> +#define VDUSE_API_VERSION_1    1
> +
>  /*
>   * Get the version of VDUSE API that kernel supported (VDUSE_API_VERSION).
>   * This is used for future extension.
> --
> 2.49.0
>