"The second Linux kernel release of 2007 is now available,
further extending the virtualization and real-time capabilities of
"Highlighting the Linux 2.6.21 update is the inclusion of the
paravirt-ops paravirtualization interface, which enables multiple
hypervisors to hook directly into Linux.
"VMware, XenSource, IBM and Red Hat first launched the effort to
provide expansive virtualization in paravirt-ops in August to make
it easier for all virtualization vendors to work in Linux. VMware's
VMI (virtual machine interface) is also included in 2.6.21 taking
advantage of paravirt-ops..."