3 files changed, 30 insertions, 28 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 28b981409a8f..060aa9f5571e 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2142,22 +2142,6 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
                 else
                         svm_disable_lbrv(svm);
                 break;
-        case MSR_K7_EVNTSEL0:
-        case MSR_K7_EVNTSEL1:
-        case MSR_K7_EVNTSEL2:
-        case MSR_K7_EVNTSEL3:
-        case MSR_K7_PERFCTR0:
-        case MSR_K7_PERFCTR1:
-        case MSR_K7_PERFCTR2:
-        case MSR_K7_PERFCTR3:
-                /*
-                 * Just discard all writes to the performance counters; this
-                 * should keep both older linux and windows 64-bit guests
-                 * happy
-                 */
-                pr_unimpl(vcpu, "unimplemented perfctr wrmsr: 0x%x data 0x%llx\n", ecx, data);
-
-                break;
         case MSR_VM_HSAVE_PA:
                 svm->hsave_msr = data;
                 break;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c08bb4cf372e..6ee929255a3d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1025,18 +1025,6 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
                 rdtscll(host_tsc);
                 guest_write_tsc(data, host_tsc);
                 break;
-        case MSR_P6_PERFCTR0:
-        case MSR_P6_PERFCTR1:
-        case MSR_P6_EVNTSEL0:
-        case MSR_P6_EVNTSEL1:
-                /*
-                 * Just discard all writes to the performance counters; this
-                 * should keep both older linux and windows 64-bit guests
-                 * happy
-                 */
-                pr_unimpl(vcpu, "unimplemented perfctr wrmsr: 0x%x data 0x%llx\n", msr_index, data);
-
-                break;
         case MSR_IA32_CR_PAT:
                 if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
                         vmcs_write64(GUEST_IA32_PAT, data);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 89862a80e32c..30492f0ba4ea 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -886,6 +886,36 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
         case MSR_IA32_MCG_STATUS:
         case MSR_IA32_MC0_CTL ... MSR_IA32_MC0_CTL + 4 * KVM_MAX_MCE_BANKS - 1:
                 return set_msr_mce(vcpu, msr, data);
+
+        /* Performance counters are not protected by a CPUID bit,
+         * so we should check all of them in the generic path for the sake of
+         * cross vendor migration.
+         * Writing a zero into the event select MSRs disables them,
+         * which we perfectly emulate ;-). Any other value should be at least
+         * reported, some guests depend on them.
+         */
+        case MSR_P6_EVNTSEL0:
+        case MSR_P6_EVNTSEL1:
+        case MSR_K7_EVNTSEL0:
+        case MSR_K7_EVNTSEL1:
+        case MSR_K7_EVNTSEL2:
+        case MSR_K7_EVNTSEL3:
+                if (data != 0)
+                        pr_unimpl(vcpu, "unimplemented perfctr wrmsr: "
+                                "0x%x data 0x%llx\n", msr, data);
+                break;
+        /* at least RHEL 4 unconditionally writes to the perfctr registers,
+         * so we ignore writes to make it happy.
+         */
+        case MSR_P6_PERFCTR0:
+        case MSR_P6_PERFCTR1:
+        case MSR_K7_PERFCTR0:
+        case MSR_K7_PERFCTR1:
+        case MSR_K7_PERFCTR2:
+        case MSR_K7_PERFCTR3:
+                pr_unimpl(vcpu, "unimplemented perfctr wrmsr: "
+                        "0x%x data 0x%llx\n", msr, data);
+                break;
         default:
                 pr_unimpl(vcpu, "unhandled wrmsr: 0x%x data %llx\n", msr, data);
                 return 1;