VEX—virtual extension framework

• US 8,327,390 B2
• Filed: 06/25/2009
• Issued: 12/04/2012
• Est. Priority Date: 04/30/2004
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Wobber, Edward P., Barham, Paul, Roeder, Thomas, Erlingsson, Ulfar Us
• Primary Examiner(s): Truong, Lechi
• Application Number:
  US12/492,045
• Publication Number:
  US 20090265715A1
• Time in Patent Office: 1,258 Days
• Field of Search: 719/328, 719/330
• US Class Current: 719/328
• 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 from a host process, the extension configured for use by the host process and comprising a service application program interface, the host process comprising a support application program interface, the method comprising:

detecting, by the computing system, a host process operation related to the service application program interface of the extension;

identifying, by the computing system, a proxy for the extension, the proxy being configured to emulate at least the service application program interface of the extension;

invoking the proxy by the host process;

instantiating, by the computing system, a virtual instance of the host process, the virtual instance being configured to emulate at least the support application program interface of the host process, the computing system being configured to detect an error in the virtual instance and return control to the host process with an error indication in response thereto;

invoking the extension by the virtual instance;

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

forwarding, to the proxy invoked by the host process, a response from the extension invoked by the virtual instance, the response being configured for use by the proxy to support the host process operation.

2. The method of claim 1, wherein the host process operation is an invocation of the extension, and wherein the proxy exposes, to the host process, the service application program interface associated with the extension.

3. The method of claim 1, wherein the virtual instance provides, to the extension, the support application program interface associated with the host process.

4. The method of claim 1, wherein the forwarding the request comprises forwarding, to a stub in the virtual instance, 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.

5. 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 instance; and

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

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

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

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

providing, in the virtual instance, 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 instance.

8. The method of claim 1, wherein the virtual instance 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.

9. The method of claim 1, wherein the host process is an operating system process and the virtual instance 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.

10. A computer readable storage medium having computer executable instructions for isolating an extension from a host process, the extension configured for use by the host process and comprising a service application program interface, the host process comprising a support application program interface, the computer readable medium comprising computer executable instructions for:

detecting a host process operation related to the service application program interface of the extension;

identifying a proxy for the extension, the proxy being configured to emulate at least the service application program interface of the extension;

instantiating a virtual process, the virtual process being configured to emulate at least the support application program interface of the host process;

invoking the proxy by the host process;

invoking the extension by the virtual process;

returning control to the host process with an error indication in response to detection of an error in the virtual instance;

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

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

11. The computer readable medium of claim 10, wherein the host process is not designed to invoke the extension.

12. The computer readable medium of claim 10, wherein the operation is an invocation of the extension and wherein the proxy exposes, to the host process, a service associated with the extension.

13. The computer readable medium of claim 10, 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.

14. The computer readable medium of claim 10, wherein the virtual process provides, to the extension, the support application program interface associated with the host process.

15. The computer readable medium of claim 10, 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.

16. The computer readable medium of claim 10, 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.

17. The computer readable medium of claim 10, 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.

18. The computer readable medium of claim 10, 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.

19. The computer readable medium of claim 18 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.

20. The computer readable medium of claim 10, 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.

21. The computer readable medium of claim 10, 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.

22. A computing device comprising:

one or more processors; and

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

creating a host process, the host process configured to perform an operation and comprising a support application program interface;

creating a virtual process, the virtual process being a virtual instance of the host process-that is configured to support an extension associated with the operation and to emulate at least the support application program interface of the host process, the extension comprising a service application program interface;

invoking a proxy by the host process, the proxy being configured to emulate at least the service application interface of the extension;

invoking the extension by the virtual process;

forwarding, to the extension invoked by the virtual process, a request from the proxy, the request associated with the operation; and

forwarding, to the proxy, a response from the extension, wherein the response can be used by the proxy to support the operation, wherein in response to detection of a non-conforming response or a failure of the extension or the virtual process, an indication enabling graceful degradation of functionality provided by the host process is provided to the host process by the proxy.

23. The computing device of claim 22, 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.

24. The computing device of claim 22, 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.

25. The computing device of claim 22, wherein the host process is an operating system process and the virtual process is a virtual machine process, the memory storage further comprising 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.

26. The computing device of claim 25, 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.