MSR_IA32_PERF_STATUS support

Index: kernel/x86.c
===================================================================
@@ -412,7 +412,7 @@ static u32 msrs_to_save[] = {
 #ifdef CONFIG_X86_64
 	MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
 #endif
-	MSR_IA32_TIME_STAMP_COUNTER,
+	MSR_IA32_TIME_STAMP_COUNTER, MSR_IA32_PERF_STATUS,
 };
 
 static unsigned num_msrs_to_save;

@@ -532,7 +532,6 @@ int kvm_get_msr_common(struct kvm_vcpu *
 	case MSR_IA32_MC0_MISC+12:
 	case MSR_IA32_MC0_MISC+16:
 	case MSR_IA32_UCODE_REV:
-	case MSR_IA32_PERF_STATUS:
 	case MSR_IA32_EBL_CR_POWERON:
 		/* MTRR registers */
 	case 0xfe:

@@ -548,6 +547,12 @@ int kvm_get_msr_common(struct kvm_vcpu *
 	case MSR_IA32_MISC_ENABLE:
 		data = vcpu->arch.ia32_misc_enable_msr;
 		break;
+	case MSR_IA32_PERF_STATUS:
+                /* These are fake values, necessary to get
+                   Darwin running */
+		data = 1000ULL /* tsc_increment_by_tick */
+                     | (((uint64_t)(4ULL /* granularity */ & 0x7)) << 40);
+		break;
 #ifdef CONFIG_X86_64
 	case MSR_EFER:
 		data = vcpu->arch.shadow_efer;