Re: [PATCH v2 5/7] xen/arm: Use sanitize values for p2m

[Julien Grall <julien@xxxxxxx>]

Hi Bertrand,

On 23/08/2021 11:32, Bertrand Marquis wrote:
> Replace the code in p2m trying to find a sane value for the VMID size
> supported and the PAR to use. We are now using the boot cpuinfo as the
> values there are sanitized during boot and the value for those
> parameters is now the safest possible value on the system.
>
> On arm32, the system will panic if there are different types of core so
> those checks were not needed anyway.
So the assumption is that if you have the same MIDR, then you must have 
the same features. I understand this is what Xen assumes today but I 
never viewed that check as the truth. It is more to limit the damage on 
most platform.
So can you confirm whether this is something that Arm guarantees?

That said, I am not against removing the code. But I would like the 
comment to be amended if this is not a correct assumption.
Cheers,

--
Julien Grall