Re: [PATCH] xen/arm: guest_walk: Only generate necessary offsets/masks

[Julien Grall <julien@xen.org>]

Hi Bertrand,

On 16/04/2021 17:04, Bertrand Marquis wrote:
>> On 5 Apr 2021, at 17:20, Julien Grall <julien@xen.org> wrote:
>>
>> From: Julien Grall <jgrall@amazon.com>
>>
>> At the moment, we are computing offsets/masks for each level and
>> granularity. This is a bit of waste given that we only need to
>> know the offsets/masks for the granularity used by the guest.
>>
>> All the LPAE information can easily be inferred with just the
>> page shift for a given granularity and the level.
>>
>> So rather than providing a set of helpers per granularity, we can
>> provide a single set that takes the granularity and the level in
>> parameters.
>>
>> With the new helpers in place, we can rework guest_walk_ld() to
>> only compute necessary information.
>>
>> Signed-off-by: Julien Grall <julien@amazon.com>
> 
> Very nice cleanup.

I have a couple of more cleanup in that area to send. So far, we are 
using a completely different set of macros for Xen page-tables. I would 
like to introduce a new set that will just pass PAGE_SHIFT to the 
existing helper.

The nice part is this means it will be easier to support other page 
granularity if we wanted :).

> 
> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
> Tested-by: Bertrand Marquis <bertrand.marquis@arm.com>

Thanks! I have committed the patch.

Cheers,

-- 
Julien Grall