Re: [PATCH v2 for 4.5] xen/arm: Add support for GICv3 for domU

[Ian Campbell <Ian.Campbell@citrix.com>]

On Wed, 2014-11-05 at 10:31 +0000, Stefano Stabellini wrote:
> On Wed, 5 Nov 2014, Ian Campbell wrote:
> > > +         * hardware GIC. Only the value XEN_DOMCTL_CONFIG_GIC_DEFAULT
> > > +         * is allowed. The DOMCTL will return the actual version of the
> > > +         * GIC.
> > > +         */
> > > +        if ( domctl->u.configuredomain.gic_version != XEN_DOMCTL_CONFIG_GIC_DEFAULT )
> > > +            return -EOPNOTSUPP;
> > 
> > EOPNOTSUPP doesn't seem quite right. EPARM  or EINVAL perhaps?
> > 
> > I'm also tempted to suggest that we should accept gic_version == the hw
> > value, i.e. by moping the switch below up and including
> >         && domctl->u.configuredomain.gic_version != gic_version
> > in the condition.
> 
> I suggested to use -EOPNOTSUPP because one day we want to be able to use
> this hypercall to choose a specific gic_version for the guest domain,
> including gicv2 on gicv3 hardware for example.

Why is EOPNOTSUPP an appropriate error code for that though?

Ian.