COOPERATIVE VIRTUAL PROCESSOR SCHEDULING

Moving scheduling of processor time for virtual processors (VPs) out of a virtualization hypervisor. A host operating system schedules VP (virtual processor) processor time. The host operating system creates VP backing threads, one for each VP of each virtual machine. There is a one-to-one mapping between each VP thread in the host operating system and each VP in the hypervisor. When a VP thread is dispatched for a slice of processor time, the host operating system calls into the hypervisor to have the hypervisor start executing the VP, and the hypervisor may perform a processor context switch for the VP. Of note is the security separation between VP scheduling and VP context switching. The hypervisor manages VP context switching in kernel mode while VP scheduling is performed in user mode. There is a security/interface boundary between the unit that schedules VP processor time and the hypervisor.