Re: [PATCH v3 01/18] nitro_enclaves: Add ioctl interface definition

[Paraschiv, Andra-Irina]

On 01/06/2020 06:02, Benjamin Herrenschmidt wrote:
> On Wed, 2020-05-27 at 09:49 +0100, Stefan Hajnoczi wrote:
> > What about feature bits or a API version number field? If you add
> > features to the NE driver, how will userspace detect them?
> >
> > Even if you intend to always compile userspace against the exact kernel
> > headers that the program will run on, it can still be useful to have an
> > API version for informational purposes and to easily prevent user
> > errors (running a new userspace binary on an old kernel where the API is
> > different).
> >
> > Finally, reserved struct fields may come in handy in the future. That
> > way userspace and the kernel don't need to explicitly handle multiple
> > struct sizes.
> Beware, Greg might disagree :)
>
> That said, yes, at least a way to query the API version would be
> useful.

I see there are several thoughts with regard to extensions possibilities. :)

I added an ioctl for getting the API version, we have now a way to query 
that info. Also, I updated the sample in this patch series to check for 
the API version.

Thanks,
Andra



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