Re: [PATCH 6/7, RFC] x86_64: basic changes for supporting compatibility mode guest

[Gerd Hoffmann <kraxel@suse.de>]

  Hi,

> If we do 32-bit dom0 kernel then the tools will pick up the 32-bit version
> of that structure. So this is only an issue for userspace if we want 64-bit
> dom0 to be able to build 32-bit domU's. I suppose this would be nice to
> have.

I think we certainly want to have that.  I'd suggest to have a look at
my kexec bits:

  http://www.suse.de/~kraxel/xen/kexec.html
  http://www.suse.de/~kraxel/patches/

They include a largely rewritten domain builder, adding support for
loading both 32bit and 64bit kernels with the 64bit tools should be easy.

> Obvious thing to do is suffix all the structs and defns in arch-x86_foo.h
> with _32 or _64 as appropriate. Then, at the end of the header, we define
> the non-suffixed versions only if defined(__i386__) or __defined__(x86_64)
> (as appropriate).

I'd suggest to suffix them with $arch instead, so we have the option to
handle even ia64 on x86 machines.

cheers,

  Gerd

-- 
Gerd Hoffmann <kraxel@suse.de>
http://www.suse.de/~kraxel/julika-dora.jpeg