Xen 4.0

["Christoph Egger" <Christoph_Egger%gmx.de@localhost>]

Hi!

Xen -unstable entered feature freeze state in favour to a
stable Xen 4.0.

NetBSD specific changes:
- xenbackendd is upstream and is launched by xend
- build system improved to reduce number of patches
  to build on NetBSD

Pending patches:
- There are patches for Balloon support written
  by Cherry and Joerg Sonnenberger but haven't got
  any patches I can submit upstream.
  If the changes are not that intrusive they can
  still go upstream for Xen 4.0.

New Xen features:
- Xen supports up to 128 virtual cpus for DomUs
  (both HVM and PV)
- Xen supports page-offlining, physical CPU hotplugging,
  physical memory hotplugging.
- Xen NUMA support is on by default now. It is no longer
  necessary to add 'numa=on'
- Xen machine check has been improved to disable memory
  and physical CPUs in error. Dom0 gets notified when this
  happens.
- There can be multiple Xen installations side by
  side in different install directories.
- Simplified guest config for HVM guests:
  The path to hvmloader and qemu-dm are optional
  and no longer mandatory.