diff --git a/src/arch/arm/isa.hh b/src/arch/arm/isa.hh
index 5e337c2..ff889fa 100644
--- a/src/arch/arm/isa.hh
+++ b/src/arch/arm/isa.hh
@@ -183,6 +183,10 @@
                 info[MISCREG_BANKED] = v;
                 return *this;
             }
+            chain banked64(bool v = true) const {
+                info[MISCREG_BANKED64] = v;
+                return *this;
+            }
             chain bankedChild(bool v = true) const {
                 info[MISCREG_BANKED_CHILD] = v;
                 return *this;
@@ -642,11 +646,25 @@
                                      inSecureState(miscRegs[MISCREG_SCR],
                                                    miscRegs[MISCREG_CPSR]);
                     flat_idx += secureReg ? 2 : 1;
+                } else {
+                    flat_idx = snsBankedIndex64((MiscRegIndex)reg,
+                        !inSecureState(miscRegs[MISCREG_SCR],
+                                       miscRegs[MISCREG_CPSR]));
                 }
             }
             return flat_idx;
         }
 
+        int
+        snsBankedIndex64(MiscRegIndex reg, bool ns) const
+        {
+            int reg_as_int = static_cast<int>(reg);
+            if (miscRegInfo[reg][MISCREG_BANKED64]) {
+                reg_as_int += (haveSecurity && !ns) ? 2 : 1;
+            }
+            return reg_as_int;
+        }
+
         std::pair<int,int> getMiscIndices(int misc_reg) const
         {
             // Note: indexes of AArch64 registers are left unchanged
diff --git a/src/arch/arm/isa/insts/data64.isa b/src/arch/arm/isa/insts/data64.isa
index a2ffb9f..f5be476 100644
--- a/src/arch/arm/isa/insts/data64.isa
+++ b/src/arch/arm/isa/insts/data64.isa
@@ -331,16 +331,18 @@
     '''
 
     msr_check_code = '''
+        auto pre_flat = (MiscRegIndex)snsBankedIndex64(dest, xc->tcBase());
         MiscRegIndex flat_idx = (MiscRegIndex) xc->tcBase()->
-            flattenRegId(RegId(MiscRegClass, dest)).index();
+            flattenRegId(RegId(MiscRegClass, pre_flat)).index();
         CPSR cpsr = Cpsr;
         ExceptionLevel el = (ExceptionLevel) (uint8_t) cpsr.el;
         %s
     ''' % (msrMrs64EnabledCheckCode % ('Write'),)
 
     mrs_check_code = '''
+        auto pre_flat = (MiscRegIndex)snsBankedIndex64(op1, xc->tcBase());
         MiscRegIndex flat_idx = (MiscRegIndex) xc->tcBase()->
-            flattenRegId(RegId(MiscRegClass, op1)).index();
+            flattenRegId(RegId(MiscRegClass, pre_flat)).index();
         CPSR cpsr = Cpsr;
         ExceptionLevel el = (ExceptionLevel) (uint8_t) cpsr.el;
         %s
@@ -509,8 +511,10 @@
     def buildMsrImmInst(mnem, inst_name, code):
         global header_output, decoder_output, exec_output
         msrImmPermission = '''
-            auto misc_index = (MiscRegIndex) xc->tcBase()->flattenRegId(
-               RegId(MiscRegClass, dest)).index();
+            auto pre_flat =
+                (MiscRegIndex)snsBankedIndex64(dest, xc->tcBase());
+            MiscRegIndex misc_index = (MiscRegIndex) xc->tcBase()->
+                flattenRegId(RegId(MiscRegClass, pre_flat)).index();
 
             if (!miscRegInfo[misc_index][MISCREG_IMPLEMENTED]) {
                     return std::make_shared<UndefinedInstruction>(
diff --git a/src/arch/arm/miscregs.cc b/src/arch/arm/miscregs.cc
index cad123f..0bae018 100644
--- a/src/arch/arm/miscregs.cc
+++ b/src/arch/arm/miscregs.cc
@@ -1075,6 +1075,12 @@
     return reg_as_int;
 }
 
+int
+snsBankedIndex64(MiscRegIndex reg, ThreadContext *tc)
+{
+    SCR scr = tc->readMiscReg(MISCREG_SCR);
+    return tc->getIsaPtr()->snsBankedIndex64(reg, scr.ns);
+}
 
 /**
  * If the reg is a child reg of a banked set, then the parent is the last
diff --git a/src/arch/arm/miscregs.hh b/src/arch/arm/miscregs.hh
index a95168b..3ce371b 100644
--- a/src/arch/arm/miscregs.hh
+++ b/src/arch/arm/miscregs.hh
@@ -949,6 +949,9 @@
         MISCREG_BANKED,  // True if the register is banked between the two
                          // security states, and this is the parent node of the
                          // two banked registers
+        MISCREG_BANKED64, // True if the register is banked between the two
+                          // security states, and this is the parent node of
+                          // the two banked registers. Used in AA64 only.
         MISCREG_BANKED_CHILD, // The entry is one of the child registers that
                               // forms a banked set of regs (along with the
                               // other child regs)
@@ -1941,6 +1944,9 @@
     int
     snsBankedIndex(MiscRegIndex reg, ThreadContext *tc, bool ns);
 
+    int
+    snsBankedIndex64(MiscRegIndex reg, ThreadContext *tc);
+
     // Takes a misc reg index and returns the root reg if its one of a set of
     // banked registers
     void