Re: [PATCH 3/3] KVM: arm64: timer: Consolidate NV configuration of virtual timers

[Oliver Upton <oliver.upton@linux.dev>]

> +void kvm_timer_vcpu_nv_init(struct kvm_vcpu *vcpu)
> +{
> +	/*
> +	 * A vcpu running at EL2 is in charge of the offset applied to
> +	 * the virtual timer, so use the physical VM offset, and point
> +	 * the vcpu offset to CNTVOFF_EL2.
> +	 *
> +	 * The virtual offset behaviour is "interesting", as it always
> +	 * applies when HCR_EL2.E2H==0, but only when accessed from EL1 when
> +	 * HCR_EL2.E2H==1. Apply it to the HV timer when E2H==0.
> +	 */

I'm definitely being pedantic, but all the talk of an HV timer when
E2H==0 isn't sitting well with me. Since a programmable E2H has gone
out the window there isn't such thing as an HV timer when E2H==0, as
FEAT_VHE isn't implemented for the VM.

And along those lines, accesses to CNTHV_*_EL2 registers should undef
when FEAT_VHE isn't implemented for the VM but I don't think we have any
enforcement of that.

-- 
Thanks,
Oliver