[Intel-gfx] [PATCH v2 5/9] vfio/mdev: Consolidate all the device_api sysfs into the core code

[Christoph Hellwig]

On Thu, Sep 09, 2021 at 04:38:45PM -0300, Jason Gunthorpe wrote:
> Every driver just emits a static string, simply feed it through the ops
> and provide a standard sysfs show function.

Looks sensible.  But can you make the attribute optional and add a
comment marking it deprecated?  Because it really is completely useless.
We don't version userspace APIs, userspae has to discover new features
individually by e.g. finding new sysfs files or just trying new ioctls.