diff --git a/target/arm/m_helper.c b/target/arm/m_helper.c
index 033a4d9261..d87b9ecd12 100644
--- a/target/arm/m_helper.c
+++ b/target/arm/m_helper.c
@@ -2465,11 +2465,17 @@ uint32_t HELPER(v7m_mrs)(CPUARMState *env, uint32_t reg)
             }
             return env->v7m.primask[M_REG_NS];
         case 0x91: /* BASEPRI_NS */
+            if (!arm_feature(env, ARM_FEATURE_M_MAIN)) {
+                goto bad_reg;
+            }
             if (!env->v7m.secure) {
                 return 0;
             }
             return env->v7m.basepri[M_REG_NS];
         case 0x93: /* FAULTMASK_NS */
+            if (!arm_feature(env, ARM_FEATURE_M_MAIN)) {
+                goto bad_reg;
+            }
             if (!env->v7m.secure) {
                 return 0;
             }
@@ -2515,8 +2521,14 @@ uint32_t HELPER(v7m_mrs)(CPUARMState *env, uint32_t reg)
         return env->v7m.primask[env->v7m.secure];
     case 17: /* BASEPRI */
     case 18: /* BASEPRI_MAX */
+        if (!arm_feature(env, ARM_FEATURE_M_MAIN)) {
+            goto bad_reg;
+        }
         return env->v7m.basepri[env->v7m.secure];
     case 19: /* FAULTMASK */
+        if (!arm_feature(env, ARM_FEATURE_M_MAIN)) {
+            goto bad_reg;
+        }
         return env->v7m.faultmask[env->v7m.secure];
     default:
     bad_reg:
@@ -2581,13 +2593,19 @@ void HELPER(v7m_msr)(CPUARMState *env, uint32_t maskreg, uint32_t val)
             env->v7m.primask[M_REG_NS] = val & 1;
             return;
         case 0x91: /* BASEPRI_NS */
-            if (!env->v7m.secure || !arm_feature(env, ARM_FEATURE_M_MAIN)) {
+            if (!arm_feature(env, ARM_FEATURE_M_MAIN)) {
+                goto bad_reg;
+            }
+            if (!env->v7m.secure) {
                 return;
             }
             env->v7m.basepri[M_REG_NS] = val & 0xff;
             return;
         case 0x93: /* FAULTMASK_NS */
-            if (!env->v7m.secure || !arm_feature(env, ARM_FEATURE_M_MAIN)) {
+            if (!arm_feature(env, ARM_FEATURE_M_MAIN)) {
+                goto bad_reg;
+            }
+            if (!env->v7m.secure) {
                 return;
             }
             env->v7m.faultmask[M_REG_NS] = val & 1;