Re: [PATCH 04/10] xen/arm: static memory initialization

[Jan Beulich <jbeulich@xxxxxxxx>]

On 18.05.2021 07:21, Penny Zheng wrote:
> This patch introduces static memory initialization, during system RAM boot up.
> 
> New func init_staticmem_pages is the equivalent of init_heap_pages, 
> responsible
> for static memory initialization.
> 
> Helper func free_staticmem_pages is the equivalent of free_heap_pages, to free
> nr_pfns pages of static memory.
> For each page, it includes the following steps:
> 1. change page state from in-use(also initialization state) to free state and
> grant PGC_reserved.
> 2. set its owner NULL and make sure this page is not a guest frame any more

But isn't the goal (as per the previous patch) to associate such pages
with a _specific_ domain?

> --- a/xen/common/page_alloc.c
> +++ b/xen/common/page_alloc.c
> @@ -150,6 +150,9 @@
>  #define p2m_pod_offline_or_broken_hit(pg) 0
>  #define p2m_pod_offline_or_broken_replace(pg) BUG_ON(pg != NULL)
>  #endif
> +#ifdef CONFIG_ARM_64
> +#include <asm/setup.h>
> +#endif

Whatever it is that's needed from this header suggests the code won't
build for other architectures. I think init_staticmem_pages() in its
current shape shouldn't live in this (common) file.

> @@ -1512,6 +1515,49 @@ static void free_heap_pages(
>      spin_unlock(&heap_lock);
>  }
>  
> +/* Equivalent of free_heap_pages to free nr_pfns pages of static memory. */
> +static void free_staticmem_pages(struct page_info *pg, unsigned long nr_pfns,
> +                                 bool need_scrub)

Right now this function gets called only from an __init one. Unless
it is intended to gain further callers, it should be marked __init
itself then. Otherwise it should be made sure that other
architectures don't include this (dead there) code.

> +{
> +    mfn_t mfn = page_to_mfn(pg);
> +    int i;

This type doesn't fit nr_pfns'es.

Jan