KVM: x86: Ignore benign host writes to "unsupported" F15H_PERF_CTL MSRs

Ignore host userspace writes of '0' to F15H_PERF_CTL MSRs KVM reports
in the MSR-to-save list, but the MSRs are ultimately unsupported.  All
MSRs in said list must be writable by userspace, e.g. if userspace sends
the list back at KVM without filtering out the MSRs it doesn't need.

Note, reads of said MSRs already have the desired behavior.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220611005755.753273-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e07c5765a551328726e5b39efe45c482a22d85c3..b70fe85608811e9c57a79eff67513af6bd53a336 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3789,6 +3789,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
        case MSR_IA32_PEBS_ENABLE:
        case MSR_IA32_DS_AREA:
        case MSR_PEBS_DATA_CFG:
+       case MSR_F15H_PERF_CTL0 ... MSR_F15H_PERF_CTR5:
                if (kvm_pmu_is_valid_msr(vcpu, msr))
                        return kvm_pmu_set_msr(vcpu, msr_info);
                /*