Re: [PATCH v2 05/15] KVM: vmx/pmu: Emulate MSR_ARCH_LBR_DEPTH for guest Arch LBR

[Like Xu <like.xu.linux@xxxxxxxxx>]

On 25/11/2022 12:05 pm, Yang Weijiang wrote:
> +static bool cpuid_enable_lbr(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
> +	struct kvm_cpuid_entry2 *entry;
> +	int depth_bit;
> +
> +	if (!kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR))
> +		return !static_cpu_has(X86_FEATURE_ARCH_LBR) &&
> +			cpuid_model_is_consistent(vcpu);

Please add selftests to cover this incompatibility.

And running the SPR vcpu model on a GNR host, the guest arch lbr
should be fully supported as long as both hosts have the same lbr_depth.