diff --git a/xen/arch/arm/arm32/traps.c b/xen/arch/arm/arm32/traps.c
index 9c9790a6d1..159e3cef8b 100644
--- a/xen/arch/arm/arm32/traps.c
+++ b/xen/arch/arm/arm32/traps.c
@@ -18,9 +18,11 @@
 
 #include <xen/lib.h>
 #include <xen/kernel.h>
+#include <xen/sched.h>
 
 #include <public/xen.h>
 
+#include <asm/mmio.h>
 #include <asm/processor.h>
 #include <asm/traps.h>
 
@@ -82,6 +84,15 @@ void do_trap_data_abort(struct cpu_user_regs *regs)
         do_unexpected_trap("Data Abort", regs);
 }
 
+void post_increment_register(const struct instr_details *instr)
+{
+    /*
+     * We have not implemented decoding of post indexing instructions for 32 bit.
+     * Thus, this should be unreachable.
+     */
+    domain_crash(current->domain);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/arm/arm64/traps.c b/xen/arch/arm/arm64/traps.c
index 9113a15c7a..e18b6b2626 100644
--- a/xen/arch/arm/arm64/traps.c
+++ b/xen/arch/arm/arm64/traps.c
@@ -17,6 +17,7 @@
  */
 
 #include <xen/lib.h>
+#include <xen/sched.h>
 
 #include <asm/hsr.h>
 #include <asm/system.h>
@@ -44,6 +45,52 @@ void do_bad_mode(struct cpu_user_regs *regs, int reason)
     panic("bad mode\n");
 }
 
+void post_increment_register(const struct instr_details *instr)
+{
+    struct cpu_user_regs *regs = guest_cpu_user_regs();
+    register_t val = 0;
+
+    /* Currently, we handle only ldr/str post indexing instructions */
+    if ( instr->state != INSTR_LDR_STR_POSTINDEXING )
+        return;
+
+    /*
+     * Handle when rn = SP
+     * Refer ArmV8 ARM DDI 0487G.b, Page - D1-2463 "Stack pointer register
+     * selection"
+     * t = SP_EL0
+     * h = SP_ELx
+     * and M[3:0] (Page - C5-474 "When exception taken from AArch64 state:")
+     */
+    if (instr->rn == 31 )
+    {
+        if ( (regs->cpsr & PSR_MODE_MASK) == PSR_MODE_EL1h )
+            val = regs->sp_el1;
+        else if ( ((regs->cpsr & PSR_MODE_MASK) == PSR_MODE_EL1t) ||
+                    ((regs->cpsr & PSR_MODE_MASK) == PSR_MODE_EL0t) )
+            val = regs->sp_el0;
+        else
+        {
+            domain_crash(current->domain);
+            return;
+        }
+    }
+    else
+        val = get_user_reg(regs, instr->rn);
+
+    val += instr->imm9;
+
+    if ( instr->rn == 31 )
+    {
+        if ( (regs->cpsr & PSR_MODE_MASK) == PSR_MODE_EL1h )
+            regs->sp_el1 = val;
+        else
+            regs->sp_el0 = val;
+    }
+    else
+        set_user_reg(regs, instr->rn, val);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/arm/decode.c b/xen/arch/arm/decode.c
index 3add87e83a..16ad0747bb 100644
--- a/xen/arch/arm/decode.c
+++ b/xen/arch/arm/decode.c
@@ -146,6 +146,7 @@ static int decode_arm64(register_t pc, mmio_info_t *info)
 
     update_dabt(dabt, opcode.ldr_str.rt, opcode.ldr_str.size, false);
 
+    dabt_instr->state = INSTR_LDR_STR_POSTINDEXING;
     dabt_instr->rn = opcode.ldr_str.rn;
     dabt_instr->imm9 = opcode.ldr_str.imm9;
 
diff --git a/xen/arch/arm/include/asm/domain.h b/xen/arch/arm/include/asm/domain.h
index c56f6e4398..ed63c2b6f9 100644
--- a/xen/arch/arm/include/asm/domain.h
+++ b/xen/arch/arm/include/asm/domain.h
@@ -281,6 +281,10 @@ static inline void arch_vcpu_block(struct vcpu *v) {}
 /* vPCI is not available on Arm */
 #define has_vpci(d)    ({ (void)(d); false; })
 
+struct arch_vcpu_io {
+    struct instr_details dabt_instr; /* when the instruction is decoded */
+};
+
 #endif /* __ASM_DOMAIN_H__ */
 
 /*
diff --git a/xen/arch/arm/include/asm/mmio.h b/xen/arch/arm/include/asm/mmio.h
index 3354d9c635..ef2c57a2d5 100644
--- a/xen/arch/arm/include/asm/mmio.h
+++ b/xen/arch/arm/include/asm/mmio.h
@@ -26,12 +26,24 @@
 
 #define MAX_IO_HANDLER  16
 
+enum instr_decode_state
+{
+    INSTR_ERROR,                    /* Error encountered while decoding instr */
+    INSTR_VALID,                    /* ISS is valid, so no need to decode */
+    /*
+     * Instruction is decoded successfully. It is a ldr/str post indexing
+     * instruction.
+     */
+    INSTR_LDR_STR_POSTINDEXING
+};
+
 typedef struct
 {
     struct hsr_dabt dabt;
     struct instr_details {
         unsigned long rn:5;
         signed int imm9:9;
+        enum instr_decode_state state;
     } dabt_instr;
     paddr_t gpa;
 } mmio_info_t;
@@ -69,14 +81,15 @@ struct vmmio {
 };
 
 enum io_state try_handle_mmio(struct cpu_user_regs *regs,
-                              const union hsr hsr,
-                              paddr_t gpa);
+                              mmio_info_t *info);
 void register_mmio_handler(struct domain *d,
                            const struct mmio_handler_ops *ops,
                            paddr_t addr, paddr_t size, void *priv);
 int domain_io_init(struct domain *d, int max_count);
 void domain_io_free(struct domain *d);
 
+void try_decode_instruction(const struct cpu_user_regs *regs,
+                            mmio_info_t *info);
 
 #endif  /* __ASM_ARM_MMIO_H__ */
 
diff --git a/xen/arch/arm/include/asm/traps.h b/xen/arch/arm/include/asm/traps.h
index 2ed2b85c6f..95c46ad391 100644
--- a/xen/arch/arm/include/asm/traps.h
+++ b/xen/arch/arm/include/asm/traps.h
@@ -109,6 +109,8 @@ static inline register_t sign_extend(const struct hsr_dabt dabt, register_t r)
     return r;
 }
 
+void post_increment_register(const struct instr_details *instr);
+
 #endif /* __ASM_ARM_TRAPS__ */
 /*
  * Local variables:
diff --git a/xen/arch/arm/io.c b/xen/arch/arm/io.c
index fad103bdbd..bea69ffb08 100644
--- a/xen/arch/arm/io.c
+++ b/xen/arch/arm/io.c
@@ -102,57 +102,79 @@ static const struct mmio_handler *find_mmio_handler(struct domain *d,
     return handler;
 }
 
+void try_decode_instruction(const struct cpu_user_regs *regs,
+                            mmio_info_t *info)
+{
+    int rc;
+
+    if ( info->dabt.valid )
+    {
+        info->dabt_instr.state = INSTR_VALID;
+
+        /*
+         * Erratum 766422: Thumb store translation fault to Hypervisor may
+         * not have correct HSR Rt value.
+         */
+        if ( check_workaround_766422() && (regs->cpsr & PSR_THUMB) &&
+             info->dabt.write )
+        {
+            rc = decode_instruction(regs, info);
+            if ( rc )
+            {
+                gprintk(XENLOG_DEBUG, "Unable to decode instruction\n");
+                info->dabt_instr.state = INSTR_ERROR;
+            }
+        }
+        return;
+    }
+
+    /*
+     * Armv8 processor does not provide a valid syndrome for decoding some
+     * instructions. So in order to process these instructions, Xen must
+     * decode them.
+     */
+    rc = decode_instruction(regs, info);
+    if ( rc )
+    {
+        gprintk(XENLOG_ERR, "Unable to decode instruction\n");
+        info->dabt_instr.state = INSTR_ERROR;
+    }
+}
+
 enum io_state try_handle_mmio(struct cpu_user_regs *regs,
-                              const union hsr hsr,
-                              paddr_t gpa)
+                              mmio_info_t *info)
 {
     struct vcpu *v = current;
     const struct mmio_handler *handler = NULL;
-    const struct hsr_dabt dabt = hsr.dabt;
-    mmio_info_t info = {
-        .gpa = gpa,
-        .dabt = dabt
-    };
+    int rc;
 
-    ASSERT(hsr.ec == HSR_EC_DATA_ABORT_LOWER_EL);
+    ASSERT(info->dabt.ec == HSR_EC_DATA_ABORT_LOWER_EL);
 
-    handler = find_mmio_handler(v->domain, info.gpa);
-    if ( !handler )
+    if ( !((info->dabt_instr.state == INSTR_VALID) || (info->dabt_instr.state == INSTR_LDR_STR_POSTINDEXING)) )
     {
-        int rc;
+        ASSERT_UNREACHABLE();
+        return IO_ABORT;
+    }
 
-        rc = try_fwd_ioserv(regs, v, &info);
+    handler = find_mmio_handler(v->domain, info->gpa);
+    if ( !handler )
+    {
+        rc = try_fwd_ioserv(regs, v, info);
         if ( rc == IO_HANDLED )
             return handle_ioserv(regs, v);
 
         return rc;
     }
 
-    /* All the instructions used on emulated MMIO region should be valid */
-    if ( !dabt.valid )
-        return IO_ABORT;
-
     /*
-     * Erratum 766422: Thumb store translation fault to Hypervisor may
-     * not have correct HSR Rt value.
+     * At this point, we know that the instruction is either valid or has been
+     * decoded successfully. Thus, Xen should be allowed to execute the
+     * instruction on the emulated MMIO region.
      */
-    if ( check_workaround_766422() && (regs->cpsr & PSR_THUMB) &&
-         dabt.write )
-    {
-        int rc;
-
-        rc = decode_instruction(regs, &info);
-        if ( rc )
-        {
-            gprintk(XENLOG_DEBUG, "Unable to decode instruction\n");
-            return IO_ABORT;
-        }
-    }
-
-    if ( info.dabt.write )
-        return handle_write(handler, v, &info);
+    if ( info->dabt.write )
+        return handle_write(handler, v, info);
     else
-        return handle_read(handler, v, &info);
+        return handle_read(handler, v, info);
 }
 
 void register_mmio_handler(struct domain *d,
diff --git a/xen/arch/arm/ioreq.c b/xen/arch/arm/ioreq.c
index 308650b400..58cd320b5a 100644
--- a/xen/arch/arm/ioreq.c
+++ b/xen/arch/arm/ioreq.c
@@ -47,6 +47,7 @@ enum io_state try_fwd_ioserv(struct cpu_user_regs *regs,
                              struct vcpu *v, mmio_info_t *info)
 {
     struct vcpu_io *vio = &v->io;
+    struct dabt_instr instr = info->dabt_instr;
     ioreq_t p = {
         .type = IOREQ_TYPE_COPY,
         .addr = info->gpa,
@@ -76,10 +77,10 @@ enum io_state try_fwd_ioserv(struct cpu_user_regs *regs,
     if ( !s )
         return IO_UNHANDLED;
 
-    if ( !info->dabt.valid )
-        return IO_ABORT;
+    ASSERT(dabt.valid);
 
     vio->req = p;
+    vio->info.dabt_instr = instr;
 
     rc = ioreq_send(s, &p, 0);
     if ( rc != IO_RETRY || v->domain->is_shutting_down )
@@ -95,6 +96,7 @@ enum io_state try_fwd_ioserv(struct cpu_user_regs *regs,
 bool arch_ioreq_complete_mmio(void)
 {
     struct vcpu *v = current;
+    struct instr_details dabt_instr = v->io.info.dabt_instr;
     struct cpu_user_regs *regs = guest_cpu_user_regs();
     const union hsr hsr = { .bits = regs->hsr };
 
@@ -106,6 +108,7 @@ bool arch_ioreq_complete_mmio(void)
 
     if ( handle_ioserv(regs, v) == IO_HANDLED )
     {
+        post_increment_register(&dabt_instr);
         advance_pc(regs, hsr);
         return true;
     }
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 7a1b679b8c..120c971b0f 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1893,6 +1893,21 @@ static bool try_map_mmio(gfn_t gfn)
     return !map_regions_p2mt(d, gfn, 1, mfn, p2m_mmio_direct_c);
 }
 
+static inline bool check_p2m(bool is_data, paddr_t gpa)
+{
+    /*
+     * First check if the translation fault can be resolved by the P2M subsystem.
+     * If that's the case nothing else to do.
+     */
+    if ( p2m_resolve_translation_fault(current->domain , gaddr_to_gfn(gpa)) )
+        return true;
+
+    if ( is_data && try_map_mmio(gaddr_to_gfn(gpa)) )
+        return true;
+
+    return false;
+}
+
 static void do_trap_stage2_abort_guest(struct cpu_user_regs *regs,
                                        const union hsr hsr)
 {
@@ -1906,6 +1921,8 @@ static void do_trap_stage2_abort_guest(struct cpu_user_regs *regs,
     paddr_t gpa;
     uint8_t fsc = xabt.fsc & ~FSC_LL_MASK;
     bool is_data = (hsr.ec == HSR_EC_DATA_ABORT_LOWER_EL);
+    mmio_info_t info;
+    enum io_state state;
 
     /*
      * If this bit has been set, it means that this stage-2 abort is caused
@@ -1959,21 +1976,52 @@ static void do_trap_stage2_abort_guest(struct cpu_user_regs *regs,
         return;
     }
     case FSC_FLT_TRANS:
+    {
+        info.gpa = gpa;
+        info.dabt = hsr.dabt;
+
         /*
-         * Attempt first to emulate the MMIO as the data abort will
-         * likely happen in an emulated region.
-         *
-         * Note that emulated region cannot be executed
+         * Assumption :- Most of the times when we get a data abort and the ISS
+         * is invalid or an instruction abort, the underlying cause is that the
+         * page tables have not been set up correctly.
          */
-        if ( is_data )
+        if ( !is_data || !info.dabt.valid )
         {
-            enum io_state state = try_handle_mmio(regs, hsr, gpa);
+            if ( check_p2m(is_data, gpa) )
+                return;
 
-            switch ( state )
-            {
+            /*
+             * If the instruction abort could not be resolved by setting the
+             * appropriate bits in the translation table, then Xen should
+             * forward the abort to the guest.
+             */
+            if ( !is_data )
+                goto inject_abt;
+        }
+
+        try_decode_instruction(regs, &info);
+
+        /*
+         * If Xen could not decode the instruction or encountered an error
+         * while decoding, then it should forward the abort to the guest.
+         */
+        if ( info.dabt_instr.state == INSTR_ERROR )
+            goto inject_abt;
+
+        state = try_handle_mmio(regs, &info);
+
+        switch ( state )
+        {
             case IO_ABORT:
                 goto inject_abt;
             case IO_HANDLED:
+                /*
+                 * If the instruction was decoded and has executed successfully
+                 * on the MMIO region, then Xen should execute the next part of
+                 * the instruction. (for eg increment the rn if it is a
+                 * post-indexing instruction.
+                 */
+                post_increment_register(&info.dabt_instr);
                 advance_pc(regs, hsr);
                 return;
             case IO_RETRY:
@@ -1982,21 +2030,18 @@ static void do_trap_stage2_abort_guest(struct cpu_user_regs *regs,
             case IO_UNHANDLED:
                 /* IO unhandled, try another way to handle it. */
                 break;
-            }
         }
 
         /*
-         * First check if the translation fault can be resolved by the
-         * P2M subsystem. If that's the case nothing else to do.
+         * If the instruction syndrome was invalid, then we already checked if
+         * this was due to a P2M fault. So no point to check again as the result
+         * will be the same.
          */
-        if ( p2m_resolve_translation_fault(current->domain,
-                                           gaddr_to_gfn(gpa)) )
-            return;
-
-        if ( is_data && try_map_mmio(gaddr_to_gfn(gpa)) )
+        if ( info.dabt.valid && check_p2m(is_data, gpa) )
             return;
 
         break;
+    }
     default:
         gprintk(XENLOG_WARNING,
                 "Unsupported FSC: HSR=%#"PRIregister" DFSC=%#x\n",
diff --git a/xen/arch/x86/include/asm/ioreq.h b/xen/arch/x86/include/asm/ioreq.h
index d06ce9a6ea..ecfe7f9fdb 100644
--- a/xen/arch/x86/include/asm/ioreq.h
+++ b/xen/arch/x86/include/asm/ioreq.h
@@ -26,6 +26,9 @@
 #include <asm/hvm/ioreq.h>
 #endif
 
+struct arch_vcpu_io {
+};
+
 #endif /* __ASM_X86_IOREQ_H__ */
 
 /*
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 10ea969c7a..406d9bc610 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -160,6 +160,8 @@ struct vcpu_io {
     /* I/O request in flight to device model. */
     enum vio_completion  completion;
     ioreq_t              req;
+    /* Arch specific info pertaining to the io request */
+    struct arch_vcpu_io  info;
 };
 
 struct vcpu
