KVM: x86: rdpmc emulation checks the counter incorrectly

The rdpmc emulation checks that the counter (ECX) is not higher than 2, without
taking into considerations bits 30:31 role (e.g., bit 30 marks whether the
counter is fixed). The fix uses the pmu information for checking the validity
of the pmu counter.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index cbecaa90399c..3dd6accb64ec 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -428,6 +428,15 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	return 1;
 }
 
+int kvm_pmu_check_pmc(struct kvm_vcpu *vcpu, unsigned pmc)
+{
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+	bool fixed = pmc & (1u << 30);
+	pmc &= ~(3u << 30);
+	return (!fixed && pmc >= pmu->nr_arch_gp_counters) ||
+		(fixed && pmc >= pmu->nr_arch_fixed_counters);
+}
+
 int kvm_pmu_read_pmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data)
 {
 	struct kvm_pmu *pmu = &vcpu->arch.pmu;