VkImportMemoryHostPointerInfoEXT

To import memory from a host pointer, add a VkImportMemoryHostPointerInfoEXT structure to the pNext chain of the VkMemoryAllocateInfo structure. The VkImportMemoryHostPointerInfoEXT structure is defined as:

typedef struct VkImportMemoryHostPointerInfoEXT {
    VkStructureType sType;
    const void* pNext;
    VkExternalMemoryHandleTypeFlagBits handleType;
    void* pHostPointer;
} VkImportMemoryHostPointerInfoEXT;

• sType is a VkStructureType value identifying this structure.
• pNext is NULL or a pointer to a structure extending this structure.
• handleType is a VkExternalMemoryHandleTypeFlagBits value specifying the handle type.
• pHostPointer is the host pointer to import from.

Importing memory from a host pointer shares ownership of the memory between the host and the Vulkan implementation. The application can continue to access the memory through the host pointer but it is the application’s responsibility to synchronize device and non-device access to the payload as defined in Host Access to Device Memory Objects.

Applications can import the same payload into multiple instances of Vulkan and multiple times into a given Vulkan instance. However, implementations may fail to import the same payload multiple times into a given physical device due to platform constraints.

Importing memory from a particular host pointer may not be possible due to additional platform-specific restrictions beyond the scope of this specification in which case the implementation must fail the memory import operation with the error code VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR.

Whether device memory objects imported from a host pointer hold a reference to their payload is undefined:. As such, the application must ensure that the imported memory range remains valid and accessible for the lifetime of the imported memory object.

Implementations may support importing host pointers for memory types which are not host-visible. In this case, after a successful call to vkAllocateMemory, the memory range imported from pHostPointer must not be accessed by the application until the VkDeviceMemory has been destroyed. Memory contents for the host memory becomes undefined: on import, and is left undefined: after the VkDeviceMemory has been destroyed. Applications must also not access host memory which is mapped to the same physical memory as pHostPointer, but mapped to a different host pointer while the VkDeviceMemory handle is valid. Implementations running on general-purpose operating systems should not support importing host pointers for memory types which are not host-visible.