Registered Extension Number




Ratification Status


Extension and Version Dependencies

  • This is a provisional extension and must be used with caution. See the description of provisional header files for enablement and stability details.


Other Extension Metadata

Last Modified Date


IP Status

No known IP claims.

  • Bill Hollings, The Brenwill Workshop Ltd.

  • Daniel Koch, NVIDIA

  • Dzmitry Malyshau, Mozilla

  • Chip Davis, CodeWeavers

  • Dan Ginsburg, Valve

  • Mike Weiblen, LunarG

  • Neil Trevett, NVIDIA

  • Alexey Knyazev, Independent


The VK_KHR_portability_subset extension allows a non-conformant Vulkan implementation to be built on top of another non-Vulkan graphics API, and identifies differences between that implementation and a fully-conformant native Vulkan implementation.

This extension provides Vulkan implementations with the ability to mark otherwise-required capabilities as unsupported, or to establish additional properties and limits that the application should adhere to in order to guarantee portable behaviour and operation across platforms, including platforms where Vulkan is not natively supported.

The goal of this specification is to document, and make queryable, capabilities which are required to be supported by a fully-conformant Vulkan 1.0 implementation, but may be optional for an implementation of the Vulkan 1.0 Portability Subset.

The intent is that this extension will be advertised only on implementations of the Vulkan 1.0 Portability Subset, and not on conformant implementations of Vulkan 1.0. Fully-conformant Vulkan implementations provide all the required capabilities, and so will not provide this extension. Therefore, the existence of this extension can be used to determine that an implementation is likely not fully conformant with the Vulkan spec.

If this extension is supported by the Vulkan implementation, the application must enable this extension.

This extension defines several new structures that can be chained to the existing structures used by certain standard Vulkan calls, in order to query for non-conformant portable behavior.

New Structures

New Enum Constants



  • Extending VkStructureType:





Version History

  • Revision 1, 2020-07-21 (Bill Hollings)

    • Initial draft.

See Also

Document Notes

For more information, see the Vulkan Specification

This page is a generated document. Fixes and changes should be made to the generator scripts, not directly.

Copyright 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0