KVM: Mask function7 ebx against host capability word9

This patch masks CPUID leaf 7 ebx against host capability word9.
Signed-off-by: NYang, Wei <wei.y.yang@intel.com>
Signed-off-by: NShan, Haitao <haitao.shan@intel.com>
Signed-off-by: NLi, Xin <xin.li@intel.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

arch/x86/kvm/x86.c

@@ -2359,6 +2359,10 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
 		F(PMM) | F(PMM_EN);
 
+	/* cpuid 7.0.ebx */
+	const u32 kvm_supported_word9_x86_features =
+		F(SMEP);
+
 	/* all calls to cpuid_count() should be made on the same cpu */
 	get_cpu();
 	do_cpuid_1_ent(entry, function, index);
@@ -2393,7 +2397,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		}
 		break;
 	}
-	/* function 4 and 0xb have additional index. */
+	/* function 4 has additional index. */
 	case 4: {
 		int i, cache_type;
 
@@ -2410,8 +2414,22 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		}
 		break;
 	}
+	case 7: {
+		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
+		/* Mask ebx against host capbability word 9 */
+		if (index == 0) {
+			entry->ebx &= kvm_supported_word9_x86_features;
+			cpuid_mask(&entry->ebx, 9);
+		} else
+			entry->ebx = 0;
+		entry->eax = 0;
+		entry->ecx = 0;
+		entry->edx = 0;
+		break;
+	}
 	case 9:
 		break;
+	/* function 0xb has additional index. */
 	case 0xb: {
 		int i, level_type;