Re: [Qemu-devel] [PATCH] Revived GUEST_BASE support for usermode emulation targets [v4]

[Paul Brook]

> > I'm pretty sure it's still broken for large offsets.
> >
> Is big offsets the intention of this patch? As far as I understood its
> for small offsets (typical 64k - on debian, ubuntu, suse, fedora and all
> the others - i checked it because it tested this), so address 0 will not
> be used in typical linux configs today to grab null pointer exceptions.

The intent of the patch is to move the guest virtual address space to a void 
conflicts with the host VM. For a 32-bit guest n a 64-bit host it makes a lot 
of sense to pick a completely unused 4G region (and probably even reserve it 
so the host doesn't start using it), which is almost certainly going to be at 
a high address.

Paul