[PATCH v10 06/29] KVM: x86/pmu: Don't ignore bits 31:30 for RDPMC index on AMD

From: Sean Christopherson
Date: Tue Jan 09 2024 - 18:05:23 EST


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@xxxxxxxxxx>
---
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)
--
2.43.0.472.g3155946c3a-goog