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

[Jason Wang]

On Mon, Jun 9, 2025 at 9:41 AM Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
> 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?

Speak too fast, there's a VDUSE_SET_API_VERSION actually.

I think we need to think if it complicates the migration compatibility or not.

> 3) If it means a brunch of new ioctls, could userspace just probe the
> new ioctls instead?
>
> Thanks

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
> >