Enabling efficient nested virtualization

A non-transitory computer readable storage medium including instructions that, when executed by a processor, cause the processor to perform a method comprising:

• executing a first virtual machine monitor (VMM) to virtualize system hardware;
• executing an upper level VMM via a virtual machine (VM) to create a nested virtualization environment;
• trapping a privileged instruction issued from an upper level OS via the upper level VMM;
• copying an execution context from the upper level VMM to a lower level VMM;
• and
• emulating the privileged instruction via the lower level VMM, the lower level VMM to receive an indication of the trapped privileged instruction from one of a physical processor of the system hardware or a parent VMM hosting the lower level VMM.

A system comprising:

• platform hardware including a processor and a memory;
• a root mode virtual machine monitor (VMM) to present virtualized platform hardware to one or more virtualization layers;
• and
• a non-root mode VMM executed via a virtual machine (VM);
• wherein the non-root mode VMM to further
• trap a privileged instruction issued from an upper level OS, and
• copy an execution context to a lower level VMM;
• and
• wherein the lower level VMM to further
• receive an indication of the trapped privileged instruction from one of the processor of the platform hardware or a parent VMM hosting the lower level VMM,
• reconstruct the execution context based on the copied execution context, and
• emulate the privileged instruction.