Re: [Qemu-devel] [PATCH 4/5] target/arm: Fill in ARMISARegisters for kvm32

[Peter Maydell]

On 29 October 2018 at 15:40, Marc Zyngier <address@hidden> wrote:
> My temptation would be not to expose it at all when running on a v7
> core, and return an error rather than zero.
>
> The other issue is that we currently don't support running 32bit KVM on
> any ARMv8 platform, as we strictly check the CPUs we want to run on (A7
> and A15). I remember seeing patches that would allow any host core to be
> used (similar to what we have on the 64bit side), but that never made it
> in the tree.

Ah, that's convenient in some ways. It means we can define the
API to be "for v7, no register available via the ONE_REG API;
for v8, always present", provided we add the constant and the
support before we turn on any actual v8 CPUs for 32-bit KVM
(avoiding the awkward case of "v8 but kernel doesn't expose
MVFR2").

I don't think we particularly care about the 32-bit-kvm-on-v8
part, but it would be good to nail down this wrinkle so we don't
forget about it, maybe ?

thanks
-- PMM