target-microblaze: mmu: Remove unused register state

Add explicit handling for MMU_R_TLBX and log accesses to
invalid MMU registers. We can now remove the state for
all regs but PID, ZPR and TLBX (0 - 2).
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>

target/microblaze/mmu.c

@@ -211,11 +211,14 @@ uint32_t mmu_read(CPUMBState *env, uint32_t rn)
             }
             r = env->mmu.regs[rn];
             break;
+        case MMU_R_TLBX:
+            r = env->mmu.regs[rn];
+            break;
         case MMU_R_TLBSX:
             qemu_log_mask(LOG_GUEST_ERROR, "TLBSX is write-only.\n");
             break;
         default:
-            r = env->mmu.regs[rn];
+            qemu_log_mask(LOG_GUEST_ERROR, "Invalid MMU register %d.\n", rn);
             break;
     }
     D(qemu_log("%s rn=%d=%x\n", __func__, rn, r));
@@ -298,7 +301,7 @@ void mmu_write(CPUMBState *env, uint32_t rn, uint32_t v)
             break;
         }
         default:
-            env->mmu.regs[rn] = v;
+            qemu_log_mask(LOG_GUEST_ERROR, "Invalid MMU register %d.\n", rn);
             break;
    }
 }

target/microblaze/mmu.h

@@ -67,7 +67,7 @@ struct microblaze_mmu
     /* We keep a separate ram for the tids to avoid the 48 bit tag width.  */
     uint8_t tids[TLB_ENTRIES];
     /* Control flops.  */
-    uint32_t regs[8];
+    uint32_t regs[3];
 
     int c_mmu;
     int c_mmu_tlb_access;