diff --git a/target-s390x/mmu_helper.c b/target-s390x/mmu_helper.c
index e8dcd0c18f..815ff42dde 100644
--- a/target-s390x/mmu_helper.c
+++ b/target-s390x/mmu_helper.c
@@ -358,7 +358,7 @@ int mmu_translate(CPUS390XState *env, target_ulong vaddr, int rw, uint64_t asc,
     /* Convert real address -> absolute address */
     *raddr = mmu_real2abs(env, *raddr);
 
-    if (*raddr <= ram_size) {
+    if (*raddr < ram_size) {
         sk = &env->storage_keys[*raddr / TARGET_PAGE_SIZE];
         if (*flags & PAGE_READ) {
             *sk |= SK_R;