Re: [PATCH v3 5/5] xen/arm: map static memory on demand

[Julien Grall <julien@xxxxxxx>]

Hi Hari,

On 28/08/2025 12:12, Hari Limaye wrote:
> From: Penny Zheng <Penny.Zheng@xxxxxxx>
>
> In the function `init_staticmem_pages` we need to have mapped static
> memory banks for initialization. Unlike on an MMU system, we cannot map
> the entire RAM
Even on the MMU system we don't always map the full RAM (for instance on 
arm32). This is why we have infrastructure like map_domain_page() 
(Temporary mapping) and map_domain_page_global() (more permanent).
on an MPU system as we have a limited number of MPU
> memory regions. To solve this, transiently map the static memory banks
> for initialization.
I am guessing you implemented the helper because in 
unmap_staticmem_pages_to_xen(), we are calling scrub_one_page(). This 
will be using map_domain_page() and unmap_domain_page(). I am a bit 
confused why we end up with brand new helpers rather than implementation 
map_domain_page() and unmap_domain_page()?
Cheers,

--
Julien Grall