Re: [RFC PATCH 0/4] KVM selftests for s390x

From: Andrew Jones
Date: Wed May 22 2019 - 04:47:01 EST


On Mon, May 20, 2019 at 01:43:06PM +0200, Paolo Bonzini wrote:
> On 20/05/19 13:30, Thomas Huth wrote:
> >> No objections at all, though it would be like to have ucall plumbed in
> >> from the beginning.
> > I'm still looking at the ucall interface ... what I don't quite get yet
> > is the question why the ucall_type there is selectable during runtime?
> >
> > Are there plans to have test that could either use UCALL_PIO or
> > UCALL_MMIO? If not, what about moving ucall_init() and ucall() to
> > architecture specific code in tools/testing/selftests/kvm/lib/aarch64/
> > and tools/testing/selftests/kvm/lib/x86_64 instead, and to remove the
> > ucall_type stuff again (so that x86 is hard-wired to PIO and aarch64
> > is hard-wired to MMIO)? ... then I could add a DIAG-based ucall
> > on s390x more easily, I think.
>
> Yes, that would work. I think Andrew wanted the flexibility to use MMIO
> on x86, but it's not really necessary to have it.

If the flexibility isn't necessary, then I agree that it'll be nicer to
put the ucall_init() in arch setup code, avoiding the need to remember
it in each unit test.

Thanks,
drew