Re: [RFC PATCH 0/6] KVM: arm64: Errata management for VM Live migration

[Marc Zyngier <maz@kernel.org>]

On Thu, 17 Oct 2024 18:16:04 +0100,
Eric Auger <eric.auger@redhat.com> wrote:
> 
> Hi Shameer,
> 
> On 10/17/24 17:49, Cornelia Huck wrote:

> > Speaking of QEMU: Do you maybe already have some prototype code that
> > tries to do something with the setup here? (I don't think QEMU currently
> > mucks around with MIDR and friends when running with KVM; I wonder what
> > it should provide to the guest and if it should care to set something as
> > a base level that gives guests not using the hypercall a chance to work
> > properly.)
> >
> As discussed during the KVM forum we are working on a qemu integration
> for writable ID regs. The first goal is to be able to specialize the
> host passthrough model (custom host model). Maybe this will trigger more
> discussions on named models too. This is complementary to the
> MIDR/REVIDR problematic and I hope we will be able to consolidate our
> works at some point.

Complementary to the MIDR/REVIDR work, I would also like to make
MIDR/REVIDR writable when this scheme is available. Ideally reporting
a synthetic CPU description (with MIDR_EL1.Implementer returning 0,
and the rest being VMM-specific, but with a clear definition for the
IMPDEF fields so that we can version the ABI).

Thoughts?

	M.

-- 
Without deviation from the norm, progress is not possible.