libxc: support of linear p2m list for migration of pv-domains

libxc: support of linear p2m list for migration of pv-domains

In order to be able to migrate pv-domains with more than 512 GB of RAM
the p2m information can be specified by the guest kernel via a virtual
mapped linear p2m list instead of a 3 level tree.

Add support for this new p2m format in libxc.

As the sanity checking of the virtual p2m address needs defines for the
xen regions use those defines when doing page table checks as well.
There were two harmless off by one errors in normalise_pagetable()
being fixed by using those defines (xen_last set to 512 instead of
511), the other one is fixed directly.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>