save/restore of domU-s different in size from dom0

save/restore of domU-s different in size from dom0

[Jan Beulich]

Looking at the present code in xc_domain_save.c, I take it for granted that
saving a 32-bit domU with a 64-bit dom0 (or vice versa) cannot be expected
to work, yet (since the vcpu context structure layout is different and domctl
returns a context matching the domain being saved, bi-modal code appears
to be necessary here). Am I missing something?

Thanks, Jan

Re: save/restore of domU-s different in size from dom0

[Keir Fraser]

On 25/4/07 15:13, "Jan Beulich" <jbeulich@novell.com> wrote:

> Looking at the present code in xc_domain_save.c, I take it for granted that
> saving a 32-bit domU with a 64-bit dom0 (or vice versa) cannot be expected
> to work, yet (since the vcpu context structure layout is different and domctl
> returns a context matching the domain being saved, bi-modal code appears
> to be necessary here). Am I missing something?

Save on 64-bit dom0 and restore on 32-bit dom0 (or vice versa) certainly
won't work as longs are used all over the place in the save format.

Currently dom0 and domU need to be matched (both 32-bit or both 64-bit). The
bitness of Xen itself does not matter. 64-bit domU save/restore with 32-bit
dom0 is probably not that interesting. 32-bit domU save/restore with 64-bit
dom0 will at least require pt_levels and hvirt_start to be initialised based
on domain-specific details.

 -- Keir