KVM: x86: expose invariant tsc cpuid bit (v2)

[Marcelo Tosatti <mtosatti@redhat.com>]

Invariant TSC is a property of TSC, no additional 
support code necessary.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index f47a104..333b88d 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -495,6 +495,13 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		entry->ecx &= kvm_supported_word6_x86_features;
 		cpuid_mask(&entry->ecx, 6);
 		break;
+	case 0x80000007: /* Advanced power management */
+		/* invariant TSC is CPUID.80000007H:EDX[8] */
+		entry->edx &= (1 << 8);
+		/* mask against host */
+		entry->edx &= boot_cpu_data.x86_power;
+		entry->eax = entry->ebx = entry->ecx = 0;
+		break;
 	case 0x80000008: {
 		unsigned g_phys_as = (entry->eax >> 16) & 0xff;
 		unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
@@ -525,7 +532,6 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 	case 3: /* Processor serial number */
 	case 5: /* MONITOR/MWAIT */
 	case 6: /* Thermal management */
-	case 0x80000007: /* Advanced power management */
 	case 0xC0000002:
 	case 0xC0000003:
 	case 0xC0000004: