diff --git a/target-sparc/cpu.c b/target-sparc/cpu.c
index ef52df6d74..cc1453e55f 100644
--- a/target-sparc/cpu.c
+++ b/target-sparc/cpu.c
@@ -580,8 +580,8 @@ static const sparc_def_t sparc_defs[] = {
         .fpu_version = 4 << 17, /* FPU version 4 (Meiko) */
         .mmu_version = 0xf3000000,
         .mmu_bm = 0x00000000,
-        .mmu_ctpr_mask = 0x007ffff0,
-        .mmu_cxr_mask = 0x0000003f,
+        .mmu_ctpr_mask = 0xfffffffc,
+        .mmu_cxr_mask = 0x000000ff,
         .mmu_sfsr_mask = 0xffffffff,
         .mmu_trcr_mask = 0xffffffff,
         .nwindows = 8,
diff --git a/target-sparc/ldst_helper.c b/target-sparc/ldst_helper.c
index 7decd66d0b..6d767fb45a 100644
--- a/target-sparc/ldst_helper.c
+++ b/target-sparc/ldst_helper.c
@@ -514,6 +514,7 @@ uint64_t helper_ld_asi(CPUSPARCState *env, target_ulong addr, int asi, int size,
 #endif
         break;
     case 3: /* MMU probe */
+    case 0x18: /* LEON3 MMU probe */
         {
             int mmulev;
 
@@ -528,6 +529,7 @@ uint64_t helper_ld_asi(CPUSPARCState *env, target_ulong addr, int asi, int size,
         }
         break;
     case 4: /* read MMU regs */
+    case 0x19: /* LEON3 read MMU regs */
         {
             int reg = (addr >> 8) & 0x1f;
 
@@ -603,6 +605,7 @@ uint64_t helper_ld_asi(CPUSPARCState *env, target_ulong addr, int asi, int size,
     case 0xf: /* D-cache data */
         break;
     case 0x20: /* MMU passthrough */
+    case 0x1c: /* LEON MMU passthrough */
         switch (size) {
         case 1:
             ret = ldub_phys(addr);
@@ -844,6 +847,7 @@ void helper_st_asi(CPUSPARCState *env, target_ulong addr, uint64_t val, int asi,
 #endif
         break;
     case 3: /* MMU flush */
+    case 0x18: /* LEON3 MMU flush */
         {
             int mmulev;
 
@@ -868,6 +872,7 @@ void helper_st_asi(CPUSPARCState *env, target_ulong addr, uint64_t val, int asi,
         }
         break;
     case 4: /* write MMU regs */
+    case 0x19: /* LEON3 write MMU regs */
         {
             int reg = (addr >> 8) & 0x1f;
             uint32_t oldreg;
@@ -996,6 +1001,7 @@ void helper_st_asi(CPUSPARCState *env, target_ulong addr, uint64_t val, int asi,
         }
         break;
     case 0x20: /* MMU passthrough */
+    case 0x1c: /* LEON MMU passthrough */
         {
             switch (size) {
             case 1: