Xen/ARM - Query about a data abort seen while reading GICD registers

[Ayan Kumar Halder <ayan.kumar.halder@xxxxxxxxxx>]

Hi Xen/Arm experts,

I am facing a very strange issue while running a baremetal application 
as a DomU guest on arm64 platform.
The baremetal app tries to read the GICD register with post indexing as 
follows :-
ldr x1, =0x3001000
ldr w2, [x1], #4 <<<------ PC = 0x40000ca8

And then I get :-
HSR=0x92000005 pc=0x00000040000ca8 gva=0x3001000 gpa=0x00000003001000

This problem occurs only while reading the GICD registers with post 
indexing. If I read the register with pre-indexing, then I do not see 
any abort. Alternatively, if I read GICC register with post indexing, I 
don't see the abort either.
From the HSR value, I interpret it as
EC = 100100b # Data abort from lower exception
IL = 1b # 32 bit instruction trapped
DFSC = 101 # Translation fault level 1

On debugging, I found that the abort is triggered from

try_handle_mmio()
{ ...
    /* All the instructions used on emulated MMIO region should be valid */
    if ( !dabt.valid ) {

        return IO_ABORT;
    }
...
}

From the Arm V8 Arm specs, I understand that dabt.valid is ISV, bit[24] 
in "ISS encoding for an exception from a Data Abort".

I saw that the caller is

do_trap_guest_sync() "case HSR_EC_DATA_ABORT_LOWER_EL"
where dabt.valid is false.
In the success scenario, dabt.valid is true.

I could not find the caller for do_trap_guest_sync()

So, can anyone help me here
1. Who is the caller for do_trap_guest_sync() ?
2. Any idea on what the issue is and how I can debug it further ?

Kind regards,
Ayan