Re: [PATCH v19 040/130] KVM: TDX: Make pmu_intel.c ignore guest TD case

[Chao Gao]

On Mon, Feb 26, 2024 at 12:25:42AM -0800, isaku.yamahata@xxxxxxxxx wrote:
>From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
>Because TDX KVM doesn't support PMU yet (it's future work of TDX KVM
>support as another patch series) and pmu_intel.c touches vmx specific
>structure in vcpu initialization, as workaround add dummy structure to
>struct vcpu_tdx and pmu_intel.c can ignore TDX case.

Can we instead factor pmu_intel.c to avoid corrupting memory? how hard would it
be?

>+bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu)
>+{
>+	struct x86_pmu_lbr *lbr = vcpu_to_lbr_records(vcpu);
>+
>+	if (is_td_vcpu(vcpu))
>+		return false;
>+
>+	return lbr->nr && (vcpu_get_perf_capabilities(vcpu) & PMU_CAP_LBR_FMT);

The check about vcpu's perf capabilities is new. is it necessary?

>-static inline bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu)
>-{
>-	return !!vcpu_to_lbr_records(vcpu)->nr;
>-}
>-