KVM: Handle writes to MCG_STATUS msr

Some older (~2.6.7) kernels write MCG_STATUS register during kernel
boot (mce_clear_all() function, called from mce_init()). It's not
currently handled by kvm and will cause it to inject a GPF.
Following patch adds a "nop" handler for this.
Signed-off-by: Sergey Kiselev <sergey.kiselev@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/kvm_main.c

@@ -1467,6 +1467,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
 		printk(KERN_WARNING "%s: MSR_IA32_MC0_STATUS 0x%llx, nop\n",
 		       __FUNCTION__, data);
 		break;
+	case MSR_IA32_MCG_STATUS:
+		printk(KERN_WARNING "%s: MSR_IA32_MCG_STATUS 0x%llx, nop\n",
+			__FUNCTION__, data);
+		break;
 	case MSR_IA32_UCODE_REV:
 	case MSR_IA32_UCODE_WRITE:
 	case 0x200 ... 0x2ff: /* MTRRs */