ENABLING EFFICIENT NESTED VIRTUALIZATION

• US 20140229943A1
• Filed: 12/22/2011
• Published: 08/14/2014
• Est. Priority Date: 12/22/2011
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Tian, Kun, Dong, Yao Zu
• Granted Patent: US 10,467,033 B2
• Time in Patent Office: Days
• US Class Current: 718/1
• CPC Class Codes: G06F 2009/45566 Nested virtual machines
• CPC Class Codes: G06F 9/45533 Hypervisors; Virtual machine monitors
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects

Abstract

Embodiments of the invention enable dynamic level boosting of operations across virtualization layers to enable efficient nested virtualization. Embodiments of the invention execute a first virtual machine monitor (VMM) to virtualize system hardware. A nested virtualization environment is created by executing a plurality of upper level VMMs via virtual machines (VMs). These upper level VMMs are used to execute an upper level virtualization layer including an operating system (OS).

During operation of the above described nested virtualization environment, a privileged instruction issued from an OS is trapped and emulated via the respective upper level VMM (i.e., the VMM that creates the VM for that OS). Embodiments of the invention enable the emulation of the privileged instruction via a lower level VMM. In some embodiments, the emulated instruction is executed via the first VMM with little to no involvement of any intermediate virtualization layers residing between the first and upper level VMMs.

Claims

1. 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 VM 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.

2. The method of claim 1, wherein the nested virtualization environment comprises one or more intermediate virtualization layers included between the first VMM and the upper level VMM, the first VMM to receive the indication of the trapped privileged instruction directly from the physical processor.

3. The method of claim 1, wherein copying an execution context from the upper level VMM to the lower level VMM includes copying a subset of a virtual processor context stored in the upper level VMM to the lower level VMM.

4. The method of claim 1, wherein copying an execution context from the upper level VMM to the lower level VMM includes copying a physical-to-machine (P2M) mapping table stored in the upper level VMM to the lower level VMM.

5. The method of claim 1, wherein the upper level VMM to store the execution context in a network file server (NFS), the NFS accessible to the VMMs.

6. The method of claim 5, wherein the NFS is included in a host machine, the host machine further including the nested virtualization environment.

7. The method of claim 1, further comprising:

copying a VM configuration pattern from the upper level VMM to the lower level VMM.

8. 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.

9. The non-transitory computer readable storage medium of claim 8, wherein the nested virtualization environment comprises one or more intermediate virtualization layers included between the first VMM and the upper level VMM, and the first VMM to receive the indication of the trapped privileged instruction directly from the physical processor.

10. The non-transitory computer readable storage medium of claim 8, wherein copying an execution context from the upper level VMM to the lower level VMM includes copying a subset of a virtual processor context stored in the upper level VMM to the lower level VMM.

11. The non-transitory computer readable storage medium of claim 8, wherein copying an execution context from the upper level VMM to the lower level VMM includes copying a physical-to-machine (P2M) mapping table stored in the upper level VMM to the lower level VMM.

12. The non-transitory computer readable storage medium of claim 8, wherein the upper level VMM to store an execution context in a network file server (NFS), and the NFS is accessible to the VMMs.

13. The non-transitory computer readable storage medium of claim 12, wherein the NFS is included in a host machine, the host machine further including the nested virtualization environment.

14. The non-transitory computer readable storage medium of claim 8, the method further comprising:

copying a VM configuration pattern from the upper level VMM to the lower level VMM.

15. 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.

16. The system of claim 15, further comprising:

one or more intermediate virtualization layers between the root mode VMM and the non-root mode VMM, wherein the root mode VMM to receive an indication of the trapped privileged instruction directly from the processor of the platform hardware.

17. The system of claim 15, the non-root mode VMM to further copy a subset of a virtual processor context to the lower level VMM.

18. The system of claim 15, the non-root mode VMM to further copy a physical-to-machine (P2M) mapping table to the lower level VMM.

19. The system of claim 15, further comprising a network file server (NFS) accessible to the VMMs of the system, wherein the non-root VMM to store an execution context in the network file server.

20. The system of claim 19, further comprising a host machine further including NFS, the VMMs to access configuration patterns for the non-root mode VMM stored on the NFS.

21. The system of claim 15, the non-root VMM to further a copy a VM configuration pattern to the lower level VMM.