Re: [Xen-devel] [PATCH] xen: arm: don't release modules which aren't in RAM into the heap

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Ian,

On 07/24/2014 11:44 AM, Ian Campbell wrote:
> On Thu, 2014-07-24 at 11:40 +0100, Julien Grall wrote:
>>> -        if ( mi->module[i].kind != BOOTMOD_XEN )
>>> -            dt_unreserved_regions(s, e, init_domheap_pages, 0);
>>> +        if ( mi->module[i].kind == BOOTMOD_XEN )
>>> +            continue;
>>> +
>>> +        if ( !mfn_valid(paddr_to_pfn(s)) || !mfn_valid(paddr_to_pfn(e)))
>>> +            continue;
>>
>> What happen if the bootloader decide to put the module between 2 banks 
>> and having the hole in the middle. Such as:
>>
>> start of the module
>>
>> end of bank 0
>>
>> hole
>>
>> start of bank 1
>>
>> end of the module
> 
> Either we will ignore bank 1, in which case these checks will prevent us
> adding them to the heap or the frame table will span bank0..1 and
> include the hole.
> 
> We don't really handle the latter case very well, but the first one is
> the one which is actually biting people today.

Thanks for the explanation. It might be worse to add a TODO to help the
person who will support sparse frame table.

Anyway:

Acked-by: Julien Grall <julien.grall@xxxxxxxxxx>

Regards,

-- 
Julien Grall

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