diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index 7cb55dc..fd3f459 100644
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -77,6 +77,32 @@
     CPUDEF_INIT(0x2965, 13, 2, 47, 0x08000000U, "z13s", "IBM z13s GA1"),
 };
 
+void s390_cpudef_featoff(uint8_t gen, uint8_t ec_ga, S390Feat feat)
+{
+    const S390CPUDef *def;
+
+    def = s390_find_cpu_def(0, gen, ec_ga, NULL);
+    clear_bit(feat, (unsigned long *)&def->default_feat);
+}
+
+void s390_cpudef_featoff_greater(uint8_t gen, uint8_t ec_ga, S390Feat feat)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(s390_cpu_defs); i++) {
+        const S390CPUDef *def = &s390_cpu_defs[i];
+
+        if (def->gen < gen) {
+            continue;
+        }
+        if (def->gen == gen && def->ec_ga < ec_ga) {
+            continue;
+        }
+
+        clear_bit(feat, (unsigned long *)&def->default_feat);
+    }
+}
+
 uint32_t s390_get_hmfai(void)
 {
     static S390CPU *cpu;
diff --git a/target/s390x/cpu_models.h b/target/s390x/cpu_models.h
index d41f8d6..c0bee15 100644
--- a/target/s390x/cpu_models.h
+++ b/target/s390x/cpu_models.h
@@ -72,6 +72,8 @@
 #define ibc_gen(x)        (x == 0 ? 0 : ((x >> 4) + S390_GEN_Z10))
 #define ibc_ec_ga(x)      (x & 0xf)
 
+void s390_cpudef_featoff(uint8_t gen, uint8_t ec_ga, S390Feat feat);
+void s390_cpudef_featoff_greater(uint8_t gen, uint8_t ec_ga, S390Feat feat);
 uint32_t s390_get_hmfai(void);
 uint8_t s390_get_mha_pow(void);
 uint32_t s390_get_ibc_val(void);