Re: [PATCH v12 6/6] xen: retrieve reserved pages on populate_physmap

[Julien Grall <julien@xxxxxxx>]

Hi Penny,

On 06/09/2022 08:39, Penny Zheng wrote:
> When a static domain populates memory through populate_physmap at runtime,
> it shall retrieve reserved pages from resv_page_list to make sure that
> guest RAM is still restricted in statically configured memory regions.
> This commit also introduces a new helper acquire_reserved_page to make it work.
>
> Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
With one remark below:

Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>

[...]

> diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
> index 18d34d1b69..215f4c234b 100644
> --- a/xen/common/page_alloc.c
> +++ b/xen/common/page_alloc.c
> @@ -2755,9 +2755,8 @@ void free_domstatic_page(struct page_info *page)
>           put_domain(d);
>   }
>   
> -static bool __init prepare_staticmem_pages(struct page_info *pg,
> -                                           unsigned long nr_mfns,
> -                                           unsigned int memflags)
> +static bool prepare_staticmem_pages(struct page_info *pg, unsigned long 
> nr_mfns,
> +                                    unsigned int memflags)
>   {
>       bool need_tlbflush = false;
>       uint32_t tlbflush_timestamp = 0;
> @@ -2838,6 +2837,25 @@ static struct page_info * __init 
> acquire_staticmem_pages(mfn_t smfn,
>       return pg;
>   }
>   
> +static int assign_domstatic_pages(struct domain *d, struct page_info *pg,
> +                                  unsigned int nr_mfns, unsigned int memflags)
> +{
> +    if ( !d || (memflags & (MEMF_no_owner | MEMF_no_refcount)) )
> +    {
> +        /*
> +         * Respective handling omitted here because right now
> +         * acquired static memory is only for guest RAM.
"guest" commonly refers to any domain other than dom0. However, I can't 
see why this code couldn't be used by dom0. So it should be s/guest/domain/.
I will modify it on commit.

> +         */
> +        ASSERT_UNREACHABLE();
> +        return -EINVAL;
> +    }
> +
> +    if ( assign_pages(pg, nr_mfns, d, memflags) )
> +        return -EINVAL;
> +
> +    return 0;
> +}
> +
Cheers,

--
Julien Grall