VK_KHR_external_memory_win32

Other Extension Metadata

Last Modified Date

2016-10-21

IP Status

No known IP claims.

Contributors

• James Jones, NVIDIA
• Jeff Juliano, NVIDIA
• Carsten Rohde, NVIDIA

Description

An application may wish to reference device memory in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension enables an application to export Windows handles from Vulkan memory objects and to import Vulkan memory objects from Windows handles exported from other Vulkan memory objects or from similar resources in other APIs.

New Commands

• vkGetMemoryWin32HandleKHR
• vkGetMemoryWin32HandlePropertiesKHR

New Structures

• VkMemoryGetWin32HandleInfoKHR
• VkMemoryWin32HandlePropertiesKHR
• Extending VkMemoryAllocateInfo:
  • VkExportMemoryWin32HandleInfoKHR
  • VkImportMemoryWin32HandleInfoKHR

New Enum Constants

• VK_KHR_EXTERNAL_MEMORY_WIN32_EXTENSION_NAME
• VK_KHR_EXTERNAL_MEMORY_WIN32_SPEC_VERSION
• Extending VkStructureType:
  • VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_KHR
  • VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_KHR
  • VK_STRUCTURE_TYPE_MEMORY_GET_WIN32_HANDLE_INFO_KHR
  • VK_STRUCTURE_TYPE_MEMORY_WIN32_HANDLE_PROPERTIES_KHR

Issues

1) Do applications need to call CloseHandle() on the values returned from vkGetMemoryWin32HandleKHR when handleType is VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR?

RESOLVED: Yes. A successful get call transfers ownership of the handle to the application. Destroying the memory object will not destroy the handle or the handle’s reference to the underlying memory resource. Unlike file descriptor opaque handles, win32 opaque handle ownership can not be transferred back to a driver by an import operation.

2) Should the language regarding KMT/Windows 7 handles be moved to a separate extension so that it can be deprecated over time?

RESOLVED: No. Support for them can be deprecated by drivers if they choose, by no longer returning them in the supported handle types of the instance level queries.

3) How should the valid size and memory type for windows memory handles created outside of Vulkan be specified?

RESOLVED: The valid memory types are queried directly from the external handle. The size is determined by the associated image or buffer memory requirements for external handle types that require dedicated allocations, and by the size specified when creating the object from which the handle was exported for other external handle types.

Version History

• Revision 1, 2016-10-21 (James Jones)
  • Initial revision