KVM: Mask function7 ebx against host capability word9

This patch masks CPUID leaf 7 ebx against host capability word9.

Signed-off-by: Yang, Wei <wei.y.yang@intel.com>
Signed-off-by: Shan, Haitao <haitao.shan@intel.com>
Signed-off-by: Li, Xin <xin.li@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 19 insertions, 1 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ba5cd27b429a..ff4623b1b102 100644
--- a/arch/x86/kvm/x86.c
+++ b/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;