CONTROL OF ENTRY INTO PROTECTED MEMORY VIEWS

• US 20160179665A1
• Filed: 12/23/2014
• Published: 06/23/2016
• Est. Priority Date: 12/23/2014
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Shanbhogue, Vedvyas, LeMay, Michael, Sahita, Ravi L., Huntley, Barry E., Durham, David M.
• Granted Patent: US 9,703,703 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 12/1009 using page tables, e.g. page table structures
• CPC Class Codes: G06F 12/1491 in a hierarchical protection system, e.g. privilege levels, memory rings
• CPC Class Codes: G06F 2009/45583 Memory management, e.g. access or allocation
• CPC Class Codes: G06F 2009/45591 Monitoring or debugging support
• CPC Class Codes: G06F 21/79 in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 2212/151 Emulated environment, e.g. virtual machine
• CPC Class Codes: G06F 2212/657 Virtual address space management
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects

Abstract

Generally, this disclosure provides systems, devices, methods and computer readable media for controlled memory view switching. The system may include a memory module comprising a shared address space between a first memory view and a second memory view. The system may also include a virtual machine monitor (VMM) to maintain a list of Controlled View Switch (CVS) descriptors. The system may further include a processor to receive a memory view switch request and to execute an instruction to save processor state information and switch from the first memory view to the second memory view, wherein the second memory view is specified by an extended page table pointer (EPTP) provided by one of the CVS descriptors.

Claims

1. A system for controlled memory view switching, said system comprising:

a memory module comprising a shared address space between a first memory view and a second memory view;

a virtual machine monitor (VMM) to maintain a list of Controlled View Switch (CVS) descriptors; and

a processor to receive a memory view switch request and to execute an instruction to save processor state information and switch from said first memory view to said second memory view, wherein said second memory view is specified by an extended page table pointer (EPTP) provided by one of said CVS descriptors.

2. The system of claim 1, wherein said instruction is a virtual machine function (VMFUNC) instruction of said processor.

3. The system of claim 1, wherein said processor is further to update an instruction pointer (IP) to an entrypoint IP in said second memory view, said entrypoint IP provided by said CVS descriptor.

4. The system of claim 1, wherein said processor is further to store an EPTP index associated with said first memory view to a register of said processor, said register available to guest software executing in said second memory view.

5. The system of claim 1, wherein said processor is further to switch a sub-page protection table pointer (SPPTP), if sub-page protection is enabled, said switching based on an SPPTP provided by said CVS descriptor.

6. The system of claim 1, further comprising a processor flags register, wherein said processor state information comprises contents of said processor flags register.

7. The system of claim 1, wherein said processor is further to update a page table pointer register of said processor based on a value provided by said CVS descriptor.

8. The system of claim 1, wherein said processor is further to update a page table pointer register of said processor based on a value provided by a target list of page table pointers stored in a said memory module.

9. The system of claim 1, wherein said processor is further to clear a trap flag of said processor.

10. The system of claim 1, wherein said processor is further to update an interrupt flag of said processor based on an interrupt flag indicator provided by said CVS descriptor.

11. At least one computer-readable storage medium having instructions stored thereon which when executed by a processor result in the following operations for controlled memory view switching, said operations comprising:

receiving a memory view switch request;

obtaining a Controlled View Switch (CVS) descriptor associated with said request;

saving processor state information; and

switching from a first memory view to a second memory view, wherein said second memory view is specified by an extended page table pointer (EPTP) provided by said CVS descriptor.

12. The computer-readable storage medium of claim 11, wherein said memory view switch request is associated with execution of a virtual machine function (VMFUNC) instruction of said processor.

13. The computer-readable storage medium of claim 11, further comprising the operation of updating the instruction pointer (IP) of said processor to an entrypoint IP provided by said CVS descriptor.

14. The computer-readable storage medium of claim 11, further comprising the operation of storing an EPTP index associated with said first memory view to a register of said processor, said register available to guest software executing in said second memory view.

15. The computer-readable storage medium of claim 11, further comprising the operation of switching a sub-page protection table pointer (SPPTP), if sub-page protection is enabled, said switching based on an SPPTP provided by said CVS descriptor.

16. The computer-readable storage medium of claim 11, wherein said processor state information comprises a processor flags register.

17. The computer-readable storage medium of claim 11, further comprising the operation of updating a page table pointer register of said processor based on a value provided by said CVS descriptor.

18. The computer-readable storage medium of claim 11, further comprising the operation of updating a page table pointer register of said processor based on a value provided by a target list of page table pointers.

19. The computer-readable storage medium of claim 11, further comprising the operation of clearing a trap flag of said processor.

20. The computer-readable storage medium of claim 11, further comprising the operation of updating an interrupt flag of said processor based on an interrupt flag indicator provided by said CVS descriptor.

21. The computer-readable storage medium of claim 11, wherein said first memory view is an untrusted view and said second memory view is a trusted protected view.

22. A system for controlled memory view switching, said system comprising:

a memory module comprising a shared address space between a first memory view and a second memory view; and

a processor to receive a memory view switch request and to execute an instruction to save processor state information and switch from said first memory view to said second memory view, wherein said second memory view is specified by an extended page table pointer (EPTP) provided by a code segment descriptor.

23. The system of claim 22, wherein said memory view switch request is associated with an interrupt of said processor and said code segment descriptor is specified by an interrupt gate.

24. The system of claim 22, wherein said memory view switch request is associated with a far call executed by said processor and said code segment descriptor is specified by a call gate.

25. The system of claim 22, wherein said memory view switch request is associated with a task switch executed by said processor and EPTP is specified by a Task-State Segment (TSS).