Re: [RFC PATCH v7 03/28] KVM: arm64: Add CONFIG_KVM_ARM_SPE Kconfig option

[Alexandru Elisei <alexandru.elisei@arm.com>]

Hi,

On Thu, Oct 15, 2026 at 03:15:18PM +0100, Lorenzo Stoakes (ARM) wrote:
> On Thu, Sep 03, 2026 at 05:05:58PM +0100, Alexandru Elisei wrote:
> > Add a new configuration option that will be used for KVM SPE emulation.
> > CONFIG_KVM_ARM_SPE depends on the SPE driver being loaded because:
> >
> > 1. The SPE driver maintains a cpumask of physical CPUs that support SPE,
> >    and that will be used by KVM to emulate SPE on heterogeneous systems.
> 
> I guess e.g. big.LITTLE?

That's the marketing term for it, yes.

> 
> >
> > 2. KVM will rely on the SPE driver enabling the SPE interrupt at the GIC
> >    level.
> >
> > The option will become user selectable after SPE support in KVM is
> > implemented.
> >
> > Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
> 
> With nit addressed the redundant dependency removed (both noted below),
> LGTM and:
> 
> Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> 
> > ---
> >  arch/arm64/kvm/Kconfig | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
> > index 449154f9a485..fece4c02b97c 100644
> > --- a/arch/arm64/kvm/Kconfig
> > +++ b/arch/arm64/kvm/Kconfig
> > @@ -103,5 +103,14 @@ config PKVM_STACKTRACE
> >  	  If unsure, or not using protected nVHE (pKVM), say N.
> >
> >  endif # NVHE_EL2_DEBUG
> > +
> > +config KVM_ARM_SPE
> 
> NIT: Nothing else in the file has the _ARM_ prefix, so is that redundant
> here?

I add the capability KVM_CAP_ARM_SPE later, so I would rather keep the config
name KVM_ARM_SPE so the two align?

> 
> > +	bool
> > +	depends on KVM && ARM_SPE_PMU
> 
> I think KVM should be removed here, this is within an 'if KVM' block
> already, and nothing else here depends on it either so not a convention.

Removed the explicit dependency on KVM.

Thanks,
Alex

> 
> > +	default n
> > +	help
> > +	  Adds support for Statistical Profiling Extension (SPE) in virtual
> > +	  machines.
> > +
> >  endif # KVM
> >  endif # VIRTUALIZATION
> > --
> > 2.43.0
> >
> >
> 
> --
> Cheers, Lorenzo