Re: [PATCH v2 0/8] pdx: introduce a new compression algorithm

[Julien Grall <julien@xxxxxxx>]

Hi Michal,

On 02/07/2025 08:52, Orzel, Michal wrote:
> We have a few issues on Arm. First, we don't check whether direct map is big
> enough provided max_pdx that we don't set at all. Second, we don't really use
> PDX grouping (can be also used without compression). My patch (that Stefano
> attached previously) fixes the second issue (Allejandro will take it over to
> come up with common solution). For the first issue, we need to know max_page (at
> the moment we calculate it in setup_mm() at the very end but we could do it in
> init_pdx() to know it ahead of setting direct map) and PDX offset (on x86 there
> is no offset). I also think that on Arm we should just panic if direct map is
> too small.
>
> The issue can be reproduced by disabling PDX compression, so not only with
> Roger's patch.
>
> @Julien, I'm thinking of something like this:
The change below look good to me.

Cheers,

--
Julien Grall