Re: [Xen-devel] [PATCH 5/9] ARM: Xen: fix initial build problems:

Stefano Stabellini
2012-10-10T14:47:42Z

On Wed, 10 Oct 2012, Ian Campbell wrote:
> On Tue, 2012-10-09 at 19:21 +0100, Arnd Bergmann wrote:
> > On Tuesday 09 October 2012, Stefano Stabellini wrote:
> > > > config XEN
> > > > bool "Xen guest support on ARM (EXPERIMENTAL)"
> > > > depends on EXPERIMENTAL && ARM && OF
> > > > + depends on !CPU_V6
> > > > help
> > > > Say Y if you want to run Linux in a Virtual Machine on Xen on ARM.
> > >
> > > Considering that we rely on the virtualization extensions, this one can
> > > be:
> > >
> > > depends on CPU_V7
> > >
> > > The rest looks fine. I can submit a second patch to change !CPU_V6 into
> > > CPU_V7 later, if you prefer.
> >
> > CPU_V6 and CPU_V7 are not exclusive, I saw the problem when building a
> > combined kernel for both V6 and V7. The code also needs to depend on ARMv7
> > with virtualization extensions, but that is a different issue. We don't
> > actually have a configuration symbol for that yet, as far as I can tell.
>
> I don't think the guest kernels (including dom0) need the extensions to
> run under Xen, they are only need by Xen itself. The guests should just
> see a relatively normal v7 processor.
>
> Stefano, does that sound right?

Keep in mind that we are using HVC to issue hypercalls, and HVC has been
introduced with the virtualization extensions, if I am not mistaken.