Xen Hypervisor-- HVM per-event-channel interrupts

by hanyandong for Xen Project

Modify Xen to allow each event channel to be bound to a separate interrupt (the association being controlled by the PV drivers in the guest) to allow separate event channel interrupts to be handled by separate vCPUs. There should be no modifications required to the guest OS interrupt logic to support this (as there is with the current Linux PV-on-HVM code) as this will not be possible with a Windows guest.