diff --git a/target-sparc/cpu.h b/target-sparc/cpu.h
index 3ae3a12..e94b8f1 100644
--- a/target-sparc/cpu.h
+++ b/target-sparc/cpu.h
@@ -225,9 +225,9 @@ enum {
 #define MAX_NWINDOWS 32
 
 #if !defined(TARGET_SPARC64)
-#define NB_MMU_MODES 2
+#define NB_MMU_MODES 3
 #else
-#define NB_MMU_MODES 6
+#define NB_MMU_MODES 7
 typedef struct trap_state {
     uint64_t tpc;
     uint64_t tnpc;
@@ -649,11 +649,13 @@ int cpu_sparc_signal_handler(int host_signum, void *pinfo, void *puc);
 #define MMU_MODE4_SUFFIX _nucleus
 #define MMU_HYPV_IDX   5
 #define MMU_MODE5_SUFFIX _hypv
+#define MMU_PHYS_IDX   6
 #else
 #define MMU_USER_IDX   0
 #define MMU_MODE0_SUFFIX _user
 #define MMU_KERNEL_IDX 1
 #define MMU_MODE1_SUFFIX _kernel
+#define MMU_PHYS_IDX   2
 #endif
 
 #if defined (TARGET_SPARC64)
@@ -673,18 +675,27 @@ static inline int cpu_supervisor_mode(CPUSPARCState *env1)
 }
 #endif
 
-static inline int cpu_mmu_index(CPUSPARCState *env1, bool ifetch)
+static inline int cpu_mmu_index(CPUSPARCState *env, bool ifetch)
 {
 #if defined(CONFIG_USER_ONLY)
     return MMU_USER_IDX;
 #elif !defined(TARGET_SPARC64)
-    return env1->psrs;
+    if ((env->mmuregs[0] & MMU_E) == 0) { /* MMU disabled */
+        return MMU_PHYS_IDX;
+    } else {
+        return env->psrs;
+    }
 #else
-    if (env1->tl > 0) {
+    /* IMMU or DMMU disabled.  */
+    if (ifetch
+        ? (env->lsu & IMMU_E) == 0 || (env->pstate & PS_RED) != 0
+        : (env->lsu & DMMU_E) == 0) {
+        return MMU_PHYS_IDX;
+    } else if (env->tl > 0) {
         return MMU_NUCLEUS_IDX;
-    } else if (cpu_hypervisor_mode(env1)) {
+    } else if (cpu_hypervisor_mode(env)) {
         return MMU_HYPV_IDX;
-    } else if (cpu_supervisor_mode(env1)) {
+    } else if (cpu_supervisor_mode(env)) {
         return MMU_KERNEL_IDX;
     } else {
         return MMU_USER_IDX;
diff --git a/target-sparc/ldst_helper.c b/target-sparc/ldst_helper.c
index 3c70766..667b962 100644
--- a/target-sparc/ldst_helper.c
+++ b/target-sparc/ldst_helper.c
@@ -887,10 +887,10 @@ void helper_st_asi(CPUSPARCState *env, target_ulong addr, uint64_t val,
             case 0: /* Control Register */
                 env->mmuregs[reg] = (env->mmuregs[reg] & 0xff000000) |
                     (val & 0x00ffffff);
-                /* Mappings generated during no-fault mode or MMU
-                   disabled mode are invalid in normal mode */
-                if ((oldreg & (MMU_E | MMU_NF | env->def->mmu_bm)) !=
-                    (env->mmuregs[reg] & (MMU_E | MMU_NF | env->def->mmu_bm))) {
+                /* Mappings generated during no-fault mode
+                   are invalid in normal mode.  */
+                if ((oldreg ^ env->mmuregs[reg])
+                    & (MMU_NF | env->def->mmu_bm)) {
                     tlb_flush(CPU(cpu), 1);
                 }
                 break;
@@ -1866,23 +1866,8 @@ void helper_st_asi(CPUSPARCState *env, target_ulong addr, target_ulong val,
         /* XXX */
         return;
     case ASI_LSU_CONTROL: /* LSU */
-        {
-            uint64_t oldreg;
-
-            oldreg = env->lsu;
-            env->lsu = val & (DMMU_E | IMMU_E);
-            /* Mappings generated during D/I MMU disabled mode are
-               invalid in normal mode */
-            if (oldreg != env->lsu) {
-                DPRINTF_MMU("LSU change: 0x%" PRIx64 " -> 0x%" PRIx64 "\n",
-                            oldreg, env->lsu);
-#ifdef DEBUG_MMU
-                dump_mmu(stdout, fprintf, env);
-#endif
-                tlb_flush(CPU(cpu), 1);
-            }
-            return;
-        }
+        env->lsu = val & (DMMU_E | IMMU_E);
+        return;
     case ASI_IMMU: /* I-MMU regs */
         {
             int reg = (addr >> 3) & 0xf;
diff --git a/target-sparc/mmu_helper.c b/target-sparc/mmu_helper.c
index 32b629f..044e88c 100644
--- a/target-sparc/mmu_helper.c
+++ b/target-sparc/mmu_helper.c
@@ -92,7 +92,7 @@ static int get_physical_address(CPUSPARCState *env, hwaddr *physical,
 
     is_user = mmu_idx == MMU_USER_IDX;
 
-    if ((env->mmuregs[0] & MMU_E) == 0) { /* MMU disabled */
+    if (mmu_idx == MMU_PHYS_IDX) {
         *page_size = TARGET_PAGE_SIZE;
         /* Boot mode: instruction fetches are taken from PROM */
         if (rw == 2 && (env->mmuregs[0] & env->def->mmu_bm)) {
@@ -494,23 +494,21 @@ static int get_physical_address_data(CPUSPARCState *env,
     unsigned int i;
     uint64_t context;
     uint64_t sfsr = 0;
-
-    int is_user = (mmu_idx == MMU_USER_IDX ||
-                   mmu_idx == MMU_USER_SECONDARY_IDX);
-
-    if ((env->lsu & DMMU_E) == 0) { /* DMMU disabled */
-        *physical = ultrasparc_truncate_physical(address);
-        *prot = PAGE_READ | PAGE_WRITE;
-        return 0;
-    }
+    bool is_user = false;
 
     switch (mmu_idx) {
+    case MMU_PHYS_IDX:
+        g_assert_not_reached();
     case MMU_USER_IDX:
+        is_user = true;
+        /* fallthru */
     case MMU_KERNEL_IDX:
         context = env->dmmu.mmu_primary_context & 0x1fff;
         sfsr |= SFSR_CT_PRIMARY;
         break;
     case MMU_USER_SECONDARY_IDX:
+        is_user = true;
+        /* fallthru */
     case MMU_KERNEL_SECONDARY_IDX:
         context = env->dmmu.mmu_secondary_context & 0x1fff;
         sfsr |= SFSR_CT_SECONDARY;
@@ -613,15 +611,22 @@ static int get_physical_address_code(CPUSPARCState *env,
     CPUState *cs = CPU(sparc_env_get_cpu(env));
     unsigned int i;
     uint64_t context;
+    bool is_user = false;
 
-    int is_user = (mmu_idx == MMU_USER_IDX ||
-                   mmu_idx == MMU_USER_SECONDARY_IDX);
-
-    if ((env->lsu & IMMU_E) == 0 || (env->pstate & PS_RED) != 0) {
-        /* IMMU disabled */
-        *physical = ultrasparc_truncate_physical(address);
-        *prot = PAGE_EXEC;
-        return 0;
+    switch (mmu_idx) {
+    case MMU_PHYS_IDX:
+    case MMU_USER_SECONDARY_IDX:
+    case MMU_KERNEL_SECONDARY_IDX:
+        g_assert_not_reached();
+    case MMU_USER_IDX:
+        is_user = true;
+        /* fallthru */
+    case MMU_KERNEL_IDX:
+        context = env->dmmu.mmu_primary_context & 0x1fff;
+        break;
+    default:
+        context = 0;
+        break;
     }
 
     if (env->tl == 0) {
@@ -700,6 +705,12 @@ static int get_physical_address(CPUSPARCState *env, hwaddr *physical,
         }
     }
 
+    if (mmu_idx == MMU_PHYS_IDX) {
+        *physical = ultrasparc_truncate_physical(address);
+        *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
+        return 0;
+    }
+
     if (rw == 2) {
         return get_physical_address_code(env, physical, prot, address,
                                          mmu_idx);
