Re: [XEN v8 2/2] xen/arm64: io: Support instructions (for which ISS is not valid) on emulated MMIO region using MMIO/ioreq handler

[Julien Grall <julien@xxxxxxx>]

On 21/02/2022 19:05, Ayan Kumar Halder wrote:
> If we (ie Xen) didn't decode the instruction manually, then check_p2m() 
> has not been invoked yet.  This is because of the following 
> (info.dabt.valid == True) :-
>          if ( !is_data || !info.dabt.valid )
>          {
>
>                  ...
>
>                  if ( check_p2m(is_data, gpa) )
>                      return;
>
>                  ...
>
>          }
>
> So, in this scenario ( !info.dabt.valid), it would not be necessary to 
> invoke check_p2m() after try_handle_mmio().
> However, if we havenot decoded the instruction manually (ie 
> info.dabt.valid == True), and try_handle_mmio() returns IO_UNHANDLED, 
> then it will be necessary to invoke "check_p2m(is_data, gpa)"
Hmmm you are right. But this doesn't seem to match the code you wrote 
below. What did I miss?
Cheers,

--
Julien Grall