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

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

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.

Ian.


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