[PATCH v3 3/8] KVM: VMX: Add helper to check reserved bits in IA32_PERF_GLOBAL_CTRL

From: Oliver Upton <oupton@google.com>
To: kvm@vger.kernel.org, "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>
Cc: Jim Mattson <jmattson@google.com>,
	Peter Shier <pshier@google.com>,
	Krish Sadhukhan <krish.sadhukhan@oracle.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Oliver Upton <oupton@google.com>
Subject: [PATCH v3 3/8] KVM: VMX: Add helper to check reserved bits in IA32_PERF_GLOBAL_CTRL
Date: Tue,  3 Sep 2019 14:57:56 -0700	[thread overview]
Message-ID: <20190903215801.183193-4-oupton@google.com> (raw)
In-Reply-To: <20190903215801.183193-1-oupton@google.com>

Create a helper function to check the validity of a proposed value for
IA32_PERF_GLOBAL_CTRL from the existing check in intel_pmu_set_msr().

Per Intel's SDM, the reserved bits in IA32_PERF_GLOBAL_CTRL must be
cleared for the corresponding host/guest state fields.

Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
---
 arch/x86/kvm/pmu.h           | 6 ++++++
 arch/x86/kvm/vmx/pmu_intel.c | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 58265f761c3b..67a0f6da567c 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -79,6 +79,12 @@ static inline bool pmc_is_enabled(struct kvm_pmc *pmc)
 	return kvm_x86_ops->pmu_ops->pmc_is_enabled(pmc);
 }
 
+static inline bool kvm_is_valid_perf_global_ctrl(struct kvm_pmu *pmu,
+						 u64 data)
+{
+	return !(pmu->global_ctrl_mask & data);
+}
+
 /* returns general purpose PMC with the specified MSR. Note that it can be
  * used for both PERFCTRn and EVNTSELn; that is why it accepts base as a
  * paramenter to tell them apart.
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 4dea0e0e7e39..963766d631ad 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -223,7 +223,7 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_CORE_PERF_GLOBAL_CTRL:
 		if (pmu->global_ctrl == data)
 			return 0;
-		if (!(data & pmu->global_ctrl_mask)) {
+		if (kvm_is_valid_perf_global_ctrl(pmu, data)) {
 			global_ctrl_changed(pmu, data);
 			return 0;
 		}
-- 
2.23.0.187.g17f5b7556c-goog

