Re: [PULL 09/11] target/arm/kvm: host cpu: Add support for sve<N> properties

[Peter Maydell]

On Thu, 3 Feb 2022 at 17:36, Andrew Jones <drjones@redhat.com> wrote:
>
> On Thu, Feb 03, 2022 at 04:46:21PM +0000, Peter Maydell wrote:
> > Was this intentional?
>
> No, darn. I don't know how many times I rebased that series and was always
> careful to ensure sve-max-vq was left in the non-kvm part of the above
> condition. I guess the final rebase finally got me...
>
> >
> > I'd like to fix up the weird divergence between -cpu host and
> > -cpu max, either by moving sve-max-vq into aarch64_add_sve_properties()
> > so it's present on both, or by changing the aarch64_max_initfn() so
> > it only adds the property when using TCG.
>
> The later, please. sve-max-vq won't work for any of the machines that
> support SVE that I know of, so I think it's a bad idea for KVM.
>
> >
> > (I think also this code may get the '-cpu max,aarch64=off' case wrong,
> > as it doesn't guard the calls to add the sve and pauth properties
> > with the "if aarch64" feature check.)
>
> Yes, but these property dependencies may need to be checked at property
> finalize time. That means that the properties may get added, but then
> they will error out if the user tried to enable them. Otherwise, they'll
> be disabled and the QMP query will inform the user that they cannot be
> enabled.

Does 'max' need to do anything different from what we're doing
already in arm_host_initfn() for 'host' ? (My proposal for
fixing this stuff is basically to make aarch64_max_initfn()
start with "if (kvm or hvf) { call arm_host_initfn(); return }".)

thanks
-- PMM