Optimizing system behavior in a virtual machine environment

• US 20060010440A1
• Filed: 07/07/2004
• Published: 01/12/2006
• Est. Priority Date: 07/07/2004
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Schoenberg, Sebastian, Anderson, Andrew V., Bennett, Steven M., Uhlig, Richard, Jeyasingh, Stalinselvaraj, Cota-Robles, Erik C., Goldsmith, Michael A., Kagi, Alani
• Granted Patent: US 7,886,293 B2
• Time in Patent Office: Days
• US Class Current: 718/1
• CPC Class Codes: G06F 11/0712 in a virtual computing platform, e.g. logically partitioned systems
• CPC Class Codes: G06F 11/0766 Error or fault reporting or storing
• CPC Class Codes: G06F 9/45533 Hypervisors; Virtual machine monitors

Abstract

In one embodiment, the present invention includes a method of transitioning control to guest software in a virtual machine from a virtual machine monitor, receiving control following a transition from the virtual machine to the virtual machine monitor upon an event, and determining whether to modify a state of the guest code, a state of the virtual machine monitor or a state of controls. If such a determination is made, the state may be modified and control is transitioned back to the guest software.

Claims

1. A method comprising:

receiving control following a transition from a virtual machine executing guest software, wherein the transition is caused by a control mechanism unavailable to the guest software; and

modifying one of a state of the guest software, a state of a virtual machine monitor and a state of the control mechanism.

2. The method of claim 1, further comprising determining whether to perform the modifying based upon occurrence of an event during execution of the guest software.

3. The method of claim 1, wherein the modifying comprises transforming an exit type of a portion of code of the guest software.

4. The method of claim 1, further comprising preventing the guest software from viewing the modified state of the guest software.

5. The method of claim 4, wherein preventing the viewing comprises marking pages of the guest software as execute-only.

6. The method of claim 1, wherein the modifying comprises reducing exits from the virtual machine.

7. The method of claim 1, further comprising programming an execution control of the guest software to cause the transition from the virtual machine.

8. The method of claim 1, further comprising modifying the state of the guest software while the guest software is resident in system memory.

9. A method comprising:

receiving control following a transition from a virtual machine executing guest software; and

modifying a first portion of the guest software while maintaining a second portion of the guest software unmodified and unanalyzed.

10. The method of claim 9, further comprising transitioning from the virtual machine based on a control mechanism unavailable to the guest software.

11. The method of claim 9, further comprising preventing the guest software from accessing the modified first portion.

12. The method of claim 9, wherein the modifying comprises changing the first portion of the guest software to change a cause of the transition.

13. The method of claim 9, wherein the first portion of the guest software comprises at least one instruction that causes a virtual machine exit.

14. The method of claim 9, further comprising modifying a state of a virtual machine monitor executing the virtual machine.

15. The method of claim 9, further comprising causing the transition by modifying at least one execution control.

16. The method of claim 9, further comprising causing the transition by modifying a page table permission of the guest software.

17. An article comprising a machine-accessible storage medium containing instructions that if executed enable a system to:

detect an event that occurs during execution of guest software; and

modify a first portion of the guest software and maintain unmodified and unanalyzed a second portion of the guest software if the event occurs.

18. The article of claim 17, wherein the article further comprises instructions that if executed enable the system to exit a virtual machine that hosts the guest software upon occurrence of the event.

19. The article of claim 17, wherein the article further comprises instructions that if executed enable the system to replace the first portion of the guest software with alternate code.

20. The article of claim 17, wherein the article further comprises instructions that if executed enable the system to modify an exit from a virtual machine that hosts the guest software.

21. The article of claim 17, wherein the article further comprises instructions that if executed enable the system to cause exits from a virtual machine that hosts the guest software to be substantially adjacent.

22. The article of claim 17, wherein the article further comprises instructions that if executed enable the system to reduce exits from a virtual machine that hosts the guest software.

23. A system comprising:

a processor; and

a dynamic random access memory coupled to the processor including instructions that if executed enable the system to detect an event that occurs during execution of guest software and modify a first portion of the guest software and maintain a second portion of the guest software unmodified and unanalyzed if the event occurs.

24. The system of claim 23, further comprising a virtual machine control structure to store criteria regarding execution of the guest software.

25. The system of claim 24, further comprising instructions that if executed enable the system to modify the criteria.

26. The system of claim 23, further comprising instructions that if executed enable the system to exit a virtual machine that hosts the guest software upon occurrence of the event.

27. The system of claim 26, further comprising instructions that if executed enable the system to modify a state of a virtual machine monitor that hosts the virtual machine.

28. An apparatus comprising:

a virtual machine monitor having;

an event detector to detect an event occurring in guest software executed on the virtual machine monitor; and

a binary modifier to modify, upon occurrence of the event, a first portion of the guest software and maintain unaltered and unanalyzed a second portion of the guest software.

29. The apparatus of claim 28, wherein the virtual machine monitor is adapted to cause a virtual machine exit via a control mechanism unavailable to the guest software.

30. The apparatus of claim 29, wherein the control mechanism comprises at least one execution control.