This patch enables INIT/SIPI handling using in-kernel APIC by
introducing a ->mp_state field to emulate the SMP state transition.

[avi: remove smp_processor_id() warning]
Signed-off-by: NQing He <qing.he@intel.com>
Signed-off-by: NXin Li <xin.b.li@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>