diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index d3db279e1b44a6183c12363c860dca2804faeb9f..01afed2037716720246d83dfb4214029e10e023e 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -327,6 +327,11 @@ static inline void set_feature(CPUARMState *env, int feature)
     env->features |= 1ULL << feature;
 }
 
+static inline void unset_feature(CPUARMState *env, int feature)
+{
+    env->features &= ~(1ULL << feature);
+}
+
 static void arm_cpu_initfn(Object *obj)
 {
     CPUState *cs = CPU(obj);