VEX - Virtual Extension Framework

• US 20090265715A1
• Filed: 06/25/2009
• Published: 10/22/2009
• Est. Priority Date: 04/30/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Wobber, Edward P., Erlingsson, Ulfar, Barham, Paul, Roeder, Thomas
• Granted Patent: US 8,327,390 B2
• Time in Patent Office: Days
• US Class Current: 719/310
• CPC Class Codes: G06F 9/4401 Bootstrapping security arrangements therefor G06F21/57
• CPC Class Codes: G06F 9/4411 Configuring for operating with peripheral devices; Loading of device drivers

Abstract

Extensions to operating systems or software applications can be hosted in virtual environments to fault isolate the extension. A generic proxy extension invoked by a host process can coordinate the invocation of an appropriate extension in a virtual process that can provide the same support APIs as the host process. Furthermore, a user mode context can be provided to the extension in the virtual process through memory copying or page table modifications. In addition, the virtual process, especially a virtual operating system process running on a virtual machine, can be efficiently started by cloning a coherent state. A coherent state can be created when a virtual machine starts up, or when the computing device starts up and the appropriate parameters are observed and saved. Alternatively, the operating system can create a coherent state by believing there is an additional CPU during the boot process.

Claims

1. A method implemented in a computing system comprising a processor and memory, the method for isolating an extension used by a host process, the method comprising the steps of:

detecting an operation by the host process, wherein the operation is related to a functionality of the extension;

identifying a proxy for the extension, wherein the proxy supports the functionality related to the operation;

loading the proxy into the host process;

loading the extension into a virtual process, wherein the virtual process is a virtual instance of the host process;

forwarding from the proxy in the host process to the extension in the virtual process a request associated with the operation; and

forwarding, to the proxy in the host process, a response from the extension, wherein the response can be used by the proxy to support the operation by the host process.

2. The method of claim 1 further comprising the steps of:

detecting an error in the virtual process; and

returning control to the host process with an error indication.

3. The method of claim 1, wherein the operation is an invocation of the extension, and wherein the proxy exposes, to the host process, a service API associated with the extension.

4. The method of claim 1, wherein the virtual process provides, to the extension, a support API associated with the host process.

5. The method of claim 1, wherein the forwarding the request comprises forwarding, to a stub in the virtual process, the request from the host process, wherein the extension receives the request from the stub in the same manner as the extension would have received the request from the host process if the extension had been loaded into the host process.

6. The method of claim 1, wherein the forwarding the response comprises:

detecting a non-conforming response or a failure of the extension or the virtual process; and

providing to the host process, by the proxy, an appropriate indication enabling graceful degradation of functionality provided by the host process.

7. The method of claim 1, further comprising the steps of:

providing, in the virtual process, a user mode context of the host process by copying the user mode context from the host process into the virtual process.

8. The method of claim 1, further comprising the steps of:

providing, in the virtual process, a user mode context of the host process by mapping a host process memory and a virtual process memory into a common physical memory; and

protecting the common physical memory from write access by the virtual process.

9. The method of claim 1, wherein the virtual process is a virtual machine process created using a saved coherent state, the saved coherent state created by performing steps comprising:

booting an initial virtual machine; and

saving a coherent state created by the boot of the initial virtual machine.

10. The method of claim 1, wherein the host process is an operating system process and the virtual process is a virtual machine process created using a saved coherent state, the saved coherent state created by recording a state during a boot of the operating system process.

11. A computer readable storage medium having computer executable instructions for isolating an extension used by a host process, the computer readable medium comprising computer executable instructions for:

detecting an operation by the host process, wherein the operation is related to a functionality of the extension;

identifying a proxy for the extension, wherein the proxy supports the functionality related to the operation;

loading the proxy into the host process;

loading the extension into a virtual process, wherein the virtual process is a virtual instance of the host process;

forwarding from the proxy in the host process to the extension in the virtual process a request associated with the operation; and

forwarding, to the proxy in the host process, a response from the extension, wherein the response can be used by the proxy to support the operation by the host process.

12. The computer readable medium of claim 11, wherein the host process is not designed to invoke the extension.

13. The computer readable medium of claim 11 comprising further computer executable instructions for:

detecting an error in the virtual process; and

returning control to the host process with an error indication.

14. The computer readable medium of claim 11, wherein the operation is an invocation of the extension and wherein the proxy exposes, to the host process, a service associated with the extension.

15. The computer readable medium of claim 11, further comprising computer executable instructions for executing a commonly invoked light-weight function of the extension in the host process using software fault isolation techniques.

16. The computer readable medium of claim 11, wherein the virtual process provides, to the extension, a support API associated with the host process.

17. The computer readable medium of claim 11, wherein the computer executable instructions for forwarding the request comprise computer executable instructions for forwarding, to a stub in the virtual process, the request from the host process, wherein the extension receives the request from the stub in the same manner as the extension would have received the request from the host process if the extension had been loaded into the host process.

18. The computer readable medium of claim 11, wherein the computer executable instructions for forwarding the response comprise computer executable instructions for:

detecting a non-conforming response or a failure of the extension or the virtual process; and

providing to the host process, by the proxy, an appropriate indication enabling graceful degradation of functionality provided by the host process.

19. The computer readable medium of claim 11, further comprising computer executable instructions for:

providing, in the virtual process, a user mode context of the host process by copying the user mode context from the host process into the virtual process.

20. The computer readable medium of claim 11, further comprising computer executable instructions for:

providing, in the virtual process, a user mode context of the host process by mapping a host process memory and a virtual process memory into a common physical memory; and

protecting the common physical memory from write access by the virtual process.

21. The computer readable medium of claim 20 wherein the protecting the common physical memory comprises implementing a memory protection scheme selected from a group of memory protection schemes comprising:

read-only access, copy-on-write access, and vetted write-back access.

22. The computer readable medium of claim 11, wherein the virtual process is a virtual machine process created using a saved coherent state, the saved coherent state created by computer executable instructions for performing steps comprising:

booting an initial virtual machine; and

saving a coherent state created by the boot of the initial virtual machine.

23. The computer readable medium of claim 11, wherein the host process is an operating system process and the virtual process is a virtual machine process created using a saved coherent state, the saved coherent state created by recording a state during a boot of the operating system process.

24. A computing device comprising:

one or more processors; and

a memory storage, the memory storage comprising computer executable instructions for;

creating a host process, wherein the host process performs an operation;

creating a virtual process, wherein the virtual process is a virtual instance of the host process, and wherein further the virtual process supports an extension associated with the operation;

loading a proxy associated with the operation into the host process;

loading the extension into the virtual process;

forwarding, to the extension, a request from the proxy; and

forwarding, to the proxy, a response from the extension, wherein the response can be used by the proxy to support the operation.

25. The computing device of claim 24, wherein the memory storage further comprises computer executable instructions for:

detecting a non-conforming response or a failure of the extension or the virtual process; and

providing to the host process, by the proxy, an appropriate indication enabling graceful degradation of functionality provided by the host process.

26. The computing device of claim 24, wherein the memory storage further comprises computer executable instructions for:

providing, in the virtual process, a user mode context of the host process by copying the user mode context from the host process into the virtual process or by mapping a host process memory and a virtual process memory into a common physical memory.

27. The computing device of claim 24, wherein the host process is an operating system process and the virtual process is a virtual machine process created using a saved coherent state, the saved coherent state created by computer executable instructions performing steps comprising:

booting an initial virtual machine and saving a state created by the boot of the initial virtual machine;

or by computer executable instructions performing steps comprising;

saving a state created by a boot of the operating system process.

28. The computing device of claim 24, wherein the host process is an operating system process and the virtual process is a virtual machine process, the memory storage further comprises computer executable instructions for:

indicating, during a boot of the operating system process, that the computing devices has one or more additional processors;

saving a state during the boot of the operating system process after the one or more processors and the one or more additional processors have been initialized;

indicating to the operating system process, after at least one component binding associated with the one or more processors has been completed by the operating system process, that the one or more additional processors have failed;

providing, to the virtual machine process, the saved state;

booting the virtual machine process using the saved state, wherein the booting the virtual machine process comprises preventing the one or more processors from accessing at least one component associated with the at least one component binding; and

providing, to the virtual machine process, access to the at least one component binding using preexisting support, wherein said preexisting support provides, to the one or more additional processors, access to the at least one component binding.

29. The computing device of claim 28, wherein the memory storage further comprises computer executable instructions for:

creating a specified component binding in the virtual machine process to a specified component, wherein the specified component interfaces with a device driver hosted within the virtual machine process.