Intelligent UEFI run-time services address space management

Patent metadata

Field	Value
Publication number	US-10185571-B2
Application number	US-201715618010-A
Country	US
Kind code	B2
Filing date	Jun 8, 2017
Priority date	Jun 8, 2017
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

A method of re-mapping memory regions for firmware run-time services to a virtual address space of a kernel executed on a processor, includes the steps of selecting a re-mapping policy for re-mapping the memory regions for the firmware run-time services, creating a new mapping according to the selected re-mapping policy, and making a call to an application programming interface exposed by the firmware to apply the new map and re-map the memory regions for the firmware to the virtual address space of the kernel.

First claim

What is claimed is:

1. A method of re-mapping memory regions for firmware run-time services to a virtual address space of a kernel executed on a processor, comprising:
selecting a re-mapping policy for re-mapping the memory regions for the firmware run-time services;
creating a new mapping according to the selected re-mapping policy; and
making a call to an application programming interface exposed by the firmware to apply the new mapping and re-map the memory regions for the firmware to the virtual address space of the kernel.

2. The method of claim 1 , wherein the firmware operates in accordance with the Unified Extensible Firmware Interface (UEFI) specification.

3. The method of claim 1 , wherein the re-mapping policy is selected from one of a plurality of re-mapping policies.

4. The method of claim 3 , wherein the selected re-mapping policy is a simple re-mapping policy according to which the run-time services memory regions are re-mapped into the virtual address space of the kernel by a fixed offset from the beginning of its virtual address space, while maintaining relative offsets between mappings of the run-time services memory regions.

5. The method of claim 3 , wherein the selected re-mapping policy is a sparse re-mapping policy according to which the run-time services memory regions are re-mapped into the virtual address space of the kernel by a fixed offset from the beginning of its virtual address space, while maintaining relative offsets between mappings of the run-time services memory regions, wherein the fixed offset is increased so as to eliminate any empty memory region at the beginning of the run-time services memory regions.

6. The method of claim 3 , wherein the selected re-mapping policy is a compact re-mapping policy according to which the run-time services memory regions are re-mapped into the virtual address space of the kernel by a fixed offset from the beginning of its virtual address space, while maintaining relative offsets between mappings of some adjacent pairs of the run-time services memory regions, wherein the fixed offset is increased so as to eliminate any empty memory region at the beginning of the run-time services memory regions and relative offsets between other adjacent pairs of the run-time services memory regions are eliminated.

7. The method of claim 3 , wherein the selected re-mapping policy is a contiguous re-mapping policy according to which the run-time services memory regions are re-mapped into one contiguous virtual address space within the kernel virtual address space.

8. The method of claim 3 , wherein the plurality of re-mapping policies is evaluated in order until one of the re-mapping policies is selected.

9. The method of claim 8 , wherein one of the re-mapping policies is selected if there is sufficient space in the virtual address space of the kernel to accommodate the new mapping that is created according to the selected re-mapping policy.

10. The method of claim 8 , wherein a special technique of invoking the firmware application programming interface to apply the selected re-mapping policy with both sets of mappings present is used, if new kernel mappings created according to the selected re-mapping policy do not conflict with existing mappings of the virtual address space of the firmware.

11. A non-transitory computer readable medium comprising instructions for causing a processor to perform a method of re-mapping memory regions for firmware run-time services to a virtual address space of a kernel executed on the processor, wherein the method comprises:
selecting a re-mapping policy for re-mapping the memory regions for the firmware run-time services;
creating a new mapping according to the selected re-mapping policy; and
making a call to an application programming interface exposed by the firmware to apply the new map and re-map the memory regions for the firmware to the virtual address space of the kernel.

12. The non-transitory computer readable medium of claim 11 , wherein the firmware operates in accordance with the Unified Extensible Firmware Interface (UEFI) specification.

13. The non-transitory computer readable medium of claim 11 , wherein the re-mapping policy is selected from one of a plurality of re-mapping policies.

14. The non-transitory computer readable medium of claim 13 , wherein the plurality of re-mapping policies is evaluated in order until one of the re-mapping policies is selected.

15. The non-transitory computer readable medium of claim 14 , wherein one of the re-mapping policies is selected if there is sufficient space in the virtual address space of the kernel to accommodate the new mapping that is created according to the selected re-mapping policy.

16. A computer system, comprising:
a system memory which includes memory regions for firmware run-time services; and
a processor configured to re-map the memory regions for the firmware run-time services to a virtual address space of a kernel executed thereon by carrying out the steps of
selecting a re-mapping policy for re-mapping the memory regions for the firmware run-time services,
creating a new mapping according to the selected re-mapping policy, and
making a call to an application programming interface exposed by the firmware to apply the new map and re-map the memory regions for the firmware to the virtual address space of the kernel.

17. The system of claim 16 , wherein the firmware operates in accordance with the Unified Extensible Firmware Interface (UEFI) specification.

18. The system of claim 16 , wherein the re-mapping policy is selected from one of a plurality of re-mapping policies.

19. The system of claim 18 , wherein the plurality of re-mapping policies is evaluated in order until one of the re-mapping policies is selected.

20. The system of claim 19 , wherein one of the re-mapping policies is selected if there is sufficient space in the virtual address space of the kernel to accommodate the new mapping that is created according to the selected re-mapping policy.

Assignees

• Vmware Inc

Inventors

• Warkentin Andrei
• Mann Timothy P
• Fainkichen Alexander

Classifications

• G06F2009/45583

  Memory management, e.g. access or allocation · CPC title

• G06F11/2284

  by power-on test, e.g. power-on self test [POST] · CPC title

• G06F11/27

  Built-in tests · CPC title

• G06F9/45558

  Hypervisor-specific management and integration aspects · CPC title

• G06F12/109

  for multiple virtual address spaces, e.g. segmentation (G06F12/1036 takes precedence) · CPC title