Virtual Processor Idle Sleep States
Virtual processors can be placed in a virtual idle processor power state, or processor sleep state. This enhanced virtual idle state allows a virtual processor that is placed into a low power idle state to be waked with the arrival of an interrupt even when interrupt is masked on the virtual processor. The virtual idle state allows the operating system in the guest partition to take advantage of processor power saving techniques in the operating system that would otherwise be unavailable when running in a guest partition.
A partition that possesses the AccessGuestIdleMsr privilege from the HV_PARTITION_PRIVILEGE_MASK enumeration can trigger entry into the virtual processor idle sleep state. The partition triggers entry into the virtual processor idle sleep state through a read to the hypervisor-defined MSR HV_X64_MSR_GUEST_IDLE. The virtual processor is waked when an interrupt arrives, regardless of whether the interrupt is enabled on the virtual processor.
Build date: 11/16/2013