[PATCH] KVM: VMX: Always treat MSR_IA32_PERF_CAPABILITIES as a valid PMU MSR

From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Like Xu <like.xu@linux.intel.com>
Subject: [PATCH] KVM: VMX: Always treat MSR_IA32_PERF_CAPABILITIES as a valid PMU MSR
Date: Wed,  3 Jun 2020 13:33:03 -0700	[thread overview]
Message-ID: <20200603203303.28545-1-sean.j.christopherson@intel.com> (raw)

Unconditionally return true when querying the validity of
MSR_IA32_PERF_CAPABILITIES so as to defer the validity check to
intel_pmu_{get,set}_msr(), which can properly give the MSR a pass when
the access is initiated from host userspace.  The MSR is emulated so
there is no underlying hardware dependency to worry about.

Fixes: 27461da31089a ("KVM: x86/pmu: Support full width counting")
Cc: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---

KVM selftests are completely hosed for me, everything fails on KVM_GET_MSRS.

 arch/x86/kvm/vmx/pmu_intel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index d33d890b605f..bdcce65c7a1d 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -181,7 +181,7 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 		ret = pmu->version > 1;
 		break;
 	case MSR_IA32_PERF_CAPABILITIES:
-		ret = guest_cpuid_has(vcpu, X86_FEATURE_PDCM);
+		ret = 1;
 		break;
 	default:
 		ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0) ||
-- 
2.26.0

