diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 0d080c1..e5f1c5b 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -345,7 +345,9 @@
 #define TCG_SVM_FEATURES 0
 #define TCG_KVM_FEATURES 0
 #define TCG_7_0_EBX_FEATURES (CPUID_7_0_EBX_SMEP | CPUID_7_0_EBX_SMAP | \
-          CPUID_7_0_EBX_BMI1 | CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ADX)
+          CPUID_7_0_EBX_BMI1 | CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ADX | \
+          CPUID_7_0_EBX_PCOMMIT | CPUID_7_0_EBX_CLFLUSHOPT |            \
+          CPUID_7_0_EBX_CLWB)
           /* missing:
           CPUID_7_0_EBX_FSGSBASE, CPUID_7_0_EBX_HLE, CPUID_7_0_EBX_AVX2,
           CPUID_7_0_EBX_ERMS, CPUID_7_0_EBX_INVPCID, CPUID_7_0_EBX_RTM,
diff --git a/target-i386/translate.c b/target-i386/translate.c
index b400d24..fbe4f80 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -7716,20 +7716,43 @@
             }
             break;
         case 5: /* lfence */
-        case 6: /* mfence */
             if ((modrm & 0xc7) != 0xc0 || !(s->cpuid_features & CPUID_SSE2))
                 goto illegal_op;
             break;
-        case 7: /* sfence / clflush */
-            if ((modrm & 0xc7) == 0xc0) {
-                /* sfence */
-                /* XXX: also check for cpuid_ext2_features & CPUID_EXT2_EMMX */
-                if (!(s->cpuid_features & CPUID_SSE))
+        case 6: /* mfence/clwb */
+            if (s->prefix & PREFIX_DATA) {
+                /* clwb */
+                if (!(s->cpuid_7_0_ebx_features & CPUID_7_0_EBX_CLWB))
                     goto illegal_op;
+                gen_nop_modrm(env, s, modrm);
             } else {
-                /* clflush */
-                if (!(s->cpuid_features & CPUID_CLFLUSH))
+                /* mfence */
+                if ((modrm & 0xc7) != 0xc0 || !(s->cpuid_features & CPUID_SSE2))
                     goto illegal_op;
+            }
+            break;
+        case 7: /* sfence / clflush / clflushopt / pcommit */
+            if ((modrm & 0xc7) == 0xc0) {
+                if (s->prefix & PREFIX_DATA) {
+                    /* pcommit */
+                    if (!(s->cpuid_7_0_ebx_features & CPUID_7_0_EBX_PCOMMIT))
+                        goto illegal_op;
+                } else {
+                    /* sfence */
+                    /* XXX: also check for cpuid_ext2_features & CPUID_EXT2_EMMX */
+                    if (!(s->cpuid_features & CPUID_SSE))
+                        goto illegal_op;
+                }
+            } else {
+                if (s->prefix & PREFIX_DATA) {
+                    /* clflushopt */
+                    if (!(s->cpuid_7_0_ebx_features & CPUID_7_0_EBX_CLFLUSHOPT))
+                        goto illegal_op;
+                } else {
+                    /* clflush */
+                    if (!(s->cpuid_features & CPUID_CLFLUSH))
+                        goto illegal_op;
+                }
                 gen_lea_modrm(env, s, modrm);
             }
             break;