linux-kernel - [PATCH v9 06/28] KVM: x86/pmu: Don't ignore bits 31:30 for RDPMC index on AMD

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Date:   Fri,  1 Dec 2023 16:03:55 -0800
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Kan Liang <kan.liang@...ux.intel.com>,
        Dapeng Mi <dapeng1.mi@...ux.intel.com>,
        Jim Mattson <jmattson@...gle.com>,
        Jinrong Liang <cloudliang@...cent.com>,
        Aaron Lewis <aaronlewis@...gle.com>,
        Like Xu <likexu@...cent.com>
Subject: [PATCH v9 06/28] KVM: x86/pmu: Don't ignore bits 31:30 for RDPMC
 index on AMD

Stop stripping bits 31:30 prior to validating/consuming the RDPMC index on
AMD.  Per the APM's documentation of RDPMC, *values* greater than 27 are
reserved.  The behavior of upper bits being flags is firmly Intel-only.

Fixes: ca724305a2b0 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM")
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/svm/pmu.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index 1475d47c821c..1fafc46f61c9 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -77,8 +77,6 @@ static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 
-	idx &= ~(3u << 30);
-
 	return idx < pmu->nr_arch_gp_counters;
 }
 
@@ -86,7 +84,7 @@ static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
 static struct kvm_pmc *amd_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu,
 	unsigned int idx, u64 *mask)
 {
-	return amd_pmc_idx_to_pmc(vcpu_to_pmu(vcpu), idx & ~(3u << 30));
+	return amd_pmc_idx_to_pmc(vcpu_to_pmu(vcpu), idx);
 }
 
 static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, u32 msr)
-- 
2.43.0.rc2.451.g8631bc7472-goog