Re: [PATCH for-4.22 v2 0/2] xen/arm: validate hwdom first bank boot placement

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Hello Mykola,

On 6/5/26 7:19 AM, Mykola Kvach wrote:
> From: Mykola Kvach <mykola_kvach@xxxxxxxx>
Just out of curiosity, is it okay that the email address listed here 
differs from the one you're using to send patches? (By the way, nice 
email address ;))
> With LLC coloring enabled, the hardware domain memory is allocated by
> allocate_hwdom_memory() instead of relying on the fixed direct-map
> layout. Since de99f3263555 ("device-tree: Improve hwdom memory
> allocation for DMA"), the allocator prefers lower host regions, but the
> first-bank filter still only enforces the old 128MB heuristic.
>
> A low candidate bank can satisfy that heuristic while still being
> unsuitable for the Arm kernel/DTB/initrd placement rules. Split the Arm
> placement logic into reusable helpers first, then validate the candidate
> hardware-domain bank 0 against those helpers before allocating it.
>
> Changes in v2:
> - Split the previous single patch into a behavior-preserving Arm
>    placement refactoring and a separate hardware-domain first-bank fix.
> - Rename find_module_placement() and place_modules() to use DTB/initrd
>    terminology.
> - Pass ramend to find_dtb_initrd_placement().
> - Update the stale tools/libs/guest/xg_dom_arm.c reference.
>
> Link to v1:
>    
> https://patchew.org/Xen/4f862bb2dc323914b8120b0f16af7516140cf42b.1780065103.git.mykola._5Fkvach@xxxxxxxx/
I would like to clarify whether my understanding is correct.

With LLC coloring enabled on ARM, the allocator could assign the 
hardware domain a bank 0 that passes the size check but is unsuitable 
for kernel/DTB/initrd placement. As a result, the hardware domain may 
fail to boot or could silently corrupt memory if the images are placed 
in an incorrect location.
Is my understanding correct?

Thanks in advance.

~ Oleksii