diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index fa3aac4f97..f0fed5d6ad 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -381,7 +381,7 @@ extern const VMStateDescription vmstate_s390_cpu;
 #define MMU_HOME_IDX            2
 #define MMU_REAL_IDX            3
 
-static inline int cpu_mmu_index(CPUS390XState *env, bool ifetch)
+static inline int s390x_env_mmu_index(CPUS390XState *env, bool ifetch)
 {
 #ifdef CONFIG_USER_ONLY
     return MMU_USER_IDX;
@@ -412,6 +412,8 @@ static inline int cpu_mmu_index(CPUS390XState *env, bool ifetch)
 #endif
 }
 
+#define cpu_mmu_index s390x_env_mmu_index
+
 #ifdef CONFIG_TCG
 
 #include "tcg/tcg_s390x.h"
diff --git a/target/s390x/tcg/mem_helper.c b/target/s390x/tcg/mem_helper.c
index 84103251b9..557831def4 100644
--- a/target/s390x/tcg/mem_helper.c
+++ b/target/s390x/tcg/mem_helper.c
@@ -358,7 +358,7 @@ static int mmu_idx_from_as(uint8_t as)
 static uint32_t do_helper_nc(CPUS390XState *env, uint32_t l, uint64_t dest,
                              uint64_t src, uintptr_t ra)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     S390Access srca1, srca2, desta;
     uint32_t i;
     uint8_t c = 0;
@@ -392,7 +392,7 @@ uint32_t HELPER(nc)(CPUS390XState *env, uint32_t l, uint64_t dest,
 static uint32_t do_helper_xc(CPUS390XState *env, uint32_t l, uint64_t dest,
                              uint64_t src, uintptr_t ra)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     S390Access srca1, srca2, desta;
     uint32_t i;
     uint8_t c = 0;
@@ -433,7 +433,7 @@ uint32_t HELPER(xc)(CPUS390XState *env, uint32_t l, uint64_t dest,
 static uint32_t do_helper_oc(CPUS390XState *env, uint32_t l, uint64_t dest,
                              uint64_t src, uintptr_t ra)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     S390Access srca1, srca2, desta;
     uint32_t i;
     uint8_t c = 0;
@@ -467,7 +467,7 @@ uint32_t HELPER(oc)(CPUS390XState *env, uint32_t l, uint64_t dest,
 static uint32_t do_helper_mvc(CPUS390XState *env, uint32_t l, uint64_t dest,
                               uint64_t src, uintptr_t ra)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     S390Access srca, desta;
     uint32_t i;
 
@@ -508,7 +508,7 @@ void HELPER(mvc)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
 /* move right to left */
 void HELPER(mvcrl)(CPUS390XState *env, uint64_t l, uint64_t dest, uint64_t src)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     const uint64_t ra = GETPC();
     S390Access srca, desta;
     int32_t i;
@@ -529,7 +529,7 @@ void HELPER(mvcrl)(CPUS390XState *env, uint64_t l, uint64_t dest, uint64_t src)
 /* move inverse  */
 void HELPER(mvcin)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     S390Access srca, desta;
     uintptr_t ra = GETPC();
     int i;
@@ -550,7 +550,7 @@ void HELPER(mvcin)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
 /* move numerics  */
 void HELPER(mvn)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     S390Access srca1, srca2, desta;
     uintptr_t ra = GETPC();
     int i;
@@ -572,7 +572,7 @@ void HELPER(mvn)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
 /* move with offset  */
 void HELPER(mvo)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     /* MVO always processes one more byte than specified - maximum is 16 */
     const int len_dest = (l >> 4) + 1;
     const int len_src = (l & 0xf) + 1;
@@ -606,7 +606,7 @@ void HELPER(mvo)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
 /* move zones  */
 void HELPER(mvz)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     S390Access srca1, srca2, desta;
     uintptr_t ra = GETPC();
     int i;
@@ -669,7 +669,7 @@ uint32_t HELPER(clm)(CPUS390XState *env, uint32_t r1, uint32_t mask,
 
     if (!mask) {
         /* Recognize access exceptions for the first byte */
-        probe_read(env, addr, 1, cpu_mmu_index(env, false), ra);
+        probe_read(env, addr, 1, s390x_env_mmu_index(env, false), ra);
     }
 
     while (mask) {
@@ -893,7 +893,7 @@ uint32_t HELPER(mvpg)(CPUS390XState *env, uint64_t r0, uint32_t r1, uint32_t r2)
 {
     const uint64_t src = get_address(env, r2) & TARGET_PAGE_MASK;
     const uint64_t dst = get_address(env, r1) & TARGET_PAGE_MASK;
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     const bool f = extract64(r0, 11, 1);
     const bool s = extract64(r0, 10, 1);
     const bool cco = extract64(r0, 8, 1);
@@ -946,7 +946,7 @@ inject_exc:
 /* string copy */
 uint32_t HELPER(mvst)(CPUS390XState *env, uint32_t r1, uint32_t r2)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     const uint64_t d = get_address(env, r1);
     const uint64_t s = get_address(env, r2);
     const uint8_t c = env->regs[0];
@@ -1027,7 +1027,7 @@ static inline uint32_t do_mvcl(CPUS390XState *env,
                                uint64_t *src, uint64_t *srclen,
                                uint16_t pad, int wordsize, uintptr_t ra)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     int len = MIN(*destlen, -(*dest | TARGET_PAGE_MASK));
     S390Access srca, desta;
     int i, cc;
@@ -1084,7 +1084,7 @@ static inline uint32_t do_mvcl(CPUS390XState *env,
 /* move long */
 uint32_t HELPER(mvcl)(CPUS390XState *env, uint32_t r1, uint32_t r2)
 {
-    const int mmu_idx = cpu_mmu_index(env, false);
+    const int mmu_idx = s390x_env_mmu_index(env, false);
     uintptr_t ra = GETPC();
     uint64_t destlen = env->regs[r1 + 1] & 0xffffff;
     uint64_t dest = get_address(env, r1);
@@ -1742,7 +1742,7 @@ uint32_t HELPER(trXX)(CPUS390XState *env, uint32_t r1, uint32_t r2,
 static uint32_t do_csst(CPUS390XState *env, uint32_t r3, uint64_t a1,
                         uint64_t a2, bool parallel)
 {
-    uint32_t mem_idx = cpu_mmu_index(env, false);
+    uint32_t mem_idx = s390x_env_mmu_index(env, false);
     MemOpIdx oi16 = make_memop_idx(MO_TE | MO_128, mem_idx);
     MemOpIdx oi8 = make_memop_idx(MO_TE | MO_64, mem_idx);
     MemOpIdx oi4 = make_memop_idx(MO_TE | MO_32, mem_idx);
@@ -2867,12 +2867,14 @@ uint32_t HELPER(cu42)(CPUS390XState *env, uint32_t r1, uint32_t r2, uint32_t m3)
 void probe_write_access(CPUS390XState *env, uint64_t addr, uint64_t len,
                         uintptr_t ra)
 {
+    const int mmu_idx = s390x_env_mmu_index(env, false);
+
     /* test the actual access, not just any access to the page due to LAP */
     while (len) {
         const uint64_t pagelen = -(addr | TARGET_PAGE_MASK);
         const uint64_t curlen = MIN(pagelen, len);
 
-        probe_write(env, addr, curlen, cpu_mmu_index(env, false), ra);
+        probe_write(env, addr, curlen, mmu_idx, ra);
         addr = wrap_address(env, addr + curlen);
         len -= curlen;
     }
