Chapter 1. General Introduction to Virtualization
1.1. What is Virtualization?
- Full virtualization
- Full virtualization uses an unmodified version of the guest operating system. The guest addresses the host’s CPU using a channel created by the hypervisor. Because the guest communicates directly with the CPU, this is the fastest virtualization method.
- Paravirtualization uses a modified guest operating system. The guest communicates with the hypervisor. The hypervisor passes the unmodified calls from the guest to the CPU and other interfaces, both real and virtual. Because the calls are routed through the hypervisor, this method is slower than full virtualization.
- Software virtualization (or emulation)
- Software virtualization uses binary translation and other emulation techniques to run unmodified operating systems. The hypervisor translates the guest calls to a format that can be used by the host system. Because all calls are translated, this method is slower than virtualization. Note that Red Hat does not support software virtualization on Red Hat Enterprise Linux.