RFC Domain Groups

The following Domain Groups patches provide a VMM-backed framework to consolidate information about a collection of domains. Today that group information can be integrated with both the scheduler and XSM. In the future, the same information could support domain disaggregation efforts.

As a demonstration, the 'xm' tool is augmented with several new commands:

grp-create: create a domain group
grp-migrate: migrate all domains in a group
grp-shutdown: shutdown all domains in a group
grp-destroy: destroy all domains in a group
grp-reboot: reboot all domains in a group
grp-pause: pause all domains in a group
grp-unpause: unpause all domains in a group
grp-save: save all domains in a group
grp-restore: restore domains with their group information
grp-join: add domain to a group
grp-list: list groups and their members

The following patches should apply cleanly to xen-unstable cs 16618.