Re: [PATCH v3 2/3] xen/arm: Extend the memory overlap check to include bootmodules

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Mon, 30 Jan 2023, Henry Wang wrote:
> Similarly as the static regions defined in bootinfo.reserved_mem,
> the bootmodule regions defined in bootinfo.modules should also not
> be overlapping with memory regions in either bootinfo.reserved_mem
> or bootinfo.modules.
> 
> Therefore, this commit introduces a helper `bootmodules_overlap_check()`
> and uses this helper to extend the check in function
> `check_reserved_regions_overlap()` so that memory regions in
> bootinfo.modules are included. Use `check_reserved_regions_overlap()`
> in `add_boot_module()` to return early if any error occurs.
> 
> Signed-off-by: Henry Wang <Henry.Wang@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> v2 -> v3:
> 1. Use "[start, end]" format in printk error message.
> 2. Change the return type of helper functions to bool.
> 3. Use 'start' and 'size' in helper functions to describe a region.
> v1 -> v2:
> 1. Split original `overlap_check()` to `bootmodules_overlap_check()`.
> 2. Rework commit message.
> ---
>  xen/arch/arm/setup.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index 636604aafa..98df0baffa 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -287,6 +287,32 @@ static bool __init meminfo_overlap_check(struct meminfo 
> *meminfo,
>      return false;
>  }
>  
> +static bool __init bootmodules_overlap_check(struct bootmodules *bootmodules,
> +                                             paddr_t region_start,
> +                                             paddr_t region_size)
> +{
> +    paddr_t mod_start = INVALID_PADDR, mod_end = 0;
> +    paddr_t region_end = region_start + region_size;
> +    unsigned int i, mod_num = bootmodules->nr_mods;
> +
> +    for ( i = 0; i < mod_num; i++ )
> +    {
> +        mod_start = bootmodules->module[i].start;
> +        mod_end = mod_start + bootmodules->module[i].size;
> +
> +        if ( region_end <= mod_start || region_start >= mod_end )
> +            continue;
> +        else
> +        {
> +            printk("Region: [%#"PRIpaddr", %#"PRIpaddr"] overlapping with 
> mod[%u]: [%#"PRIpaddr", %#"PRIpaddr"]\n",
> +                   region_start, region_end, i, mod_start, mod_end);
> +            return true;
> +        }
> +    }
> +
> +    return false;
> +}
> +
>  void __init fw_unreserved_regions(paddr_t s, paddr_t e,
>                                    void (*cb)(paddr_t, paddr_t),
>                                    unsigned int first)
> @@ -311,6 +337,11 @@ bool __init check_reserved_regions_overlap(paddr_t 
> region_start,
>                                 region_start, region_size) )
>          return true;
>  
> +    /* Check if input region is overlapping with bootmodules */
> +    if ( bootmodules_overlap_check(&bootinfo.modules,
> +                                   region_start, region_size) )
> +        return true;
> +
>      return false;
>  }
>  
> @@ -328,6 +359,10 @@ struct bootmodule __init 
> *add_boot_module(bootmodule_kind kind,
>                 boot_module_kind_as_string(kind), start, start + size);
>          return NULL;
>      }
> +
> +    if ( check_reserved_regions_overlap(start, size) )
> +        return NULL;
> +
>      for ( i = 0 ; i < mods->nr_mods ; i++ )
>      {
>          mod = &mods->module[i];
> -- 
> 2.25.1
>