In one embodiment, a method includes transitioning control to a virtual
machine (VM) upon receiving a request from a virtual machine monitor
(VMM), determining that the request to transition control is associated
with a request to be informed of an open event window, performing an
event window check to determine whether an even window of the VM is open,
and transitioning control to the VMM if the event window check indicates
that the event window of the VM is open.