A hypervisor is a program that allows multiple operating systems to share a single hardware host. In KVM, the Linux kernel acts as a Type 2 Hypervisor, streamlining management and improving performance in virtualized environments. The hypervisor creates VM environments and coordinates calls for processor, memory, hard disk, network, and other resources through the host OS.
Numerous guest OSs can work with KVM including BSD (Berkeley Software Distribution), Solaris, Windows, Haiku, ReactOS, Plan 9, and the AROS Research OS. In addition, a modified version of QEMU ("Quick Emulator") can use KVM to run Mac OS X.