Re: [PATCH v8 0/7] KVM: arm64: PMU: Use multiple host PMUs

[Marc Zyngier <maz@kernel.org>]

On Mon, 06 Jul 2026 19:28:20 +0100,
Oliver Upton <oupton@kernel.org> wrote:
> 
> On Mon, Jul 06, 2026 at 07:03:23PM +0900, Akihiko Odaki wrote:
> > Akihiko Odaki (7):
> >       KVM: arm64: Disallow vPMU when pPMUs do not cover all CPUs
> >       KVM: arm64: PMU: Protect the list of PMUs with RCU
> >       KVM: arm64: PMU: Pass the pPMU to kvm_map_pmu_event()
> >       KVM: arm64: PMU: Pass the target CPU to kvm_pmu_probe_armpmu()
> >       KVM: arm64: PMU: Implement fixed-counters-only emulation
> >       KVM: arm64: PMU: Introduce FIXED_COUNTERS_ONLY
> >       KVM: arm64: selftests: Test PMU_V3_FIXED_COUNTERS_ONLY
> 
> Thanks for respinning the series, I left some comments. I'd really like
> to get this feature picked up, hope you have cycles to work on it soon.
> 
> FWIW, we're considering adding a new vCPU feature flag to deprecate all
> the ugliness of the old PMUv3 UAPI. I'm tempted to say that the
> FIXED_COUNTERS_ONLY feature is conditioned on the new feature flag...

It'd be good to have a strawman proposal on the list if we are going
to change add a new API, specially if this is likely to gate new code.

Thanks,

	M.

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