1. In a virtual computing environment, a method of switching between isolated virtual contexts, the method comprising: determining that a virtual processor should switch from a first virtual machine context to a second virtual machine context, wherein the first and second virtual machine contexts are isolated from each other; a physical processor receiving an instruction included in the instruction set architecture for the physical processor indicating that the virtual processor should switch directly from the first virtual machine context to the second virtual machine context; and as a result, performing the virtual context switch by executing functions native to the physical processor defined natively for the instruction.