Applications may wish to export memory to other Vulkan instances or
other APIs, or import memory from other Vulkan instances or other APIs
to enable Vulkan workloads to be split up across application module,
process, or API boundaries. This extension enables win32 applications to
export win32 handles from Vulkan memory objects such that the underlying
resources can be referenced outside the Vulkan instance that created
them, and import win32 handles created in the Direct3D API to Vulkan
memory objects.
1) If memory objects are shared between processes and APIs, is this
considered aliasing according to the rules outlined in the
Memory Aliasing
section?
RESOLVED: Yes, but strict exceptions to the rules are added to allow
some forms of aliasing in these cases. Further, other extensions may
build upon these new aliasing rules to define specific support usage
within Vulkan for imported native memory objects, or memory objects from
other APIs.
2) Are new image layouts or metadata required to specify image layouts
and layout transitions compatible with non-Vulkan APIs, or with other
instances of the same Vulkan driver?
RESOLVED: No. Separate instances of the same Vulkan driver running
on the same GPU should have identical internal layout semantics, so
applications have the tools they need to ensure views of images are
consistent between the two instances. Other APIs will fall into two
categories: Those that are Vulkan compatible (a term to be defined by
subsequent interopability extensions), or Vulkan incompatible. When
sharing images with Vulkan incompatible APIs, the Vulkan image must be
transitioned to the
IMAGE_LAYOUT_GENERAL layout before
handing it off to the external API.
Note this does not attempt to address cross-device transitions, nor
transitions to engines on the same device which are not visible within
the Vulkan API. Both of these are beyond the scope of this extension.
RESOLVED: Yes, unless it is passed back in to another driver
instance to import the object. A successful get call transfers ownership
of the handle to the application, while an import transfers ownership to
the associated driver. Destroying the memory object will not destroy the
handle or the handle’s reference to the underlying memory resource.
Examples
//
// Create an exportable memory object and export an external
// handle from it.
//
// Pick an external format and handle type.
static const VkFormat format = VK_FORMAT_R8G8B8A8_UNORM;
static const VkExternalMemoryHandleTypeFlagsNV handleType =
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV;
extern VkPhysicalDevice physicalDevice;
extern VkDevice device;
VkPhysicalDeviceMemoryProperties memoryProperties;
VkExternalImageFormatPropertiesNV properties;
VkExternalMemoryImageCreateInfoNV externalMemoryImageCreateInfo;
VkDedicatedAllocationImageCreateInfoNV dedicatedImageCreateInfo;
VkImageCreateInfo imageCreateInfo;
VkImage image;
VkMemoryRequirements imageMemoryRequirements;
uint32_t numMemoryTypes;
uint32_t memoryType;
VkExportMemoryAllocateInfoNV exportMemoryAllocateInfo;
VkDedicatedAllocationMemoryAllocateInfoNV dedicatedAllocationInfo;
VkMemoryAllocateInfo memoryAllocateInfo;
VkDeviceMemory memory;
VkResult result;
HANDLE memoryHnd;
// Figure out how many memory types the device supports
vkGetPhysicalDeviceMemoryProperties(physicalDevice,
&memoryProperties);
numMemoryTypes = memoryProperties.memoryTypeCount;
// Check the external handle type capabilities for the chosen format
// Exportable 2D image support with at least 1 mip level, 1 array
// layer, and VK_SAMPLE_COUNT_1_BIT using optimal tiling and supporting
// texturing and color rendering is required.
result = vkGetPhysicalDeviceExternalImageFormatPropertiesNV(
physicalDevice,
format,
VK_IMAGE_TYPE_2D,
VK_IMAGE_TILING_OPTIMAL,
VK_IMAGE_USAGE_SAMPLED_BIT |
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT,
0,
handleType,
&properties);
if ((result != VK_SUCCESS) ||
!(properties.externalMemoryFeatures &
VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT_NV)) {
abort();
}
// Set up the external memory image creation info
memset(&externalMemoryImageCreateInfo,
0, sizeof(externalMemoryImageCreateInfo));
externalMemoryImageCreateInfo.sType =
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV;
externalMemoryImageCreateInfo.handleTypes = handleType;
if (properties.externalMemoryFeatures &
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV) {
memset(&dedicatedImageCreateInfo, 0, sizeof(dedicatedImageCreateInfo));
dedicatedImageCreateInfo.sType =
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV;
dedicatedImageCreateInfo.dedicatedAllocation = VK_TRUE;
externalMemoryImageCreateInfo.pNext = &dedicatedImageCreateInfo;
}
// Set up the core image creation info
memset(&imageCreateInfo, 0, sizeof(imageCreateInfo));
imageCreateInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
imageCreateInfo.pNext = &externalMemoryImageCreateInfo;
imageCreateInfo.format = format;
imageCreateInfo.extent.width = 64;
imageCreateInfo.extent.height = 64;
imageCreateInfo.extent.depth = 1;
imageCreateInfo.mipLevels = 1;
imageCreateInfo.arrayLayers = 1;
imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
imageCreateInfo.usage = VK_IMAGE_USAGE_SAMPLED_BIT |
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
imageCreateInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
imageCreateInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
vkCreateImage(device, &imageCreateInfo, NULL, &image);
vkGetImageMemoryRequirements(device,
image,
&imageMemoryRequirements);
// For simplicity, just pick the first compatible memory type.
for (memoryType = 0; memoryType < numMemoryTypes; memoryType++) {
if ((1 << memoryType) & imageMemoryRequirements.memoryTypeBits) {
break;
}
}
// At least one memory type must be supported given the prior external
// handle capability check.
assert(memoryType < numMemoryTypes);
// Allocate the external memory object.
memset(&exportMemoryAllocateInfo, 0, sizeof(exportMemoryAllocateInfo));
exportMemoryAllocateInfo.sType =
VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV;
exportMemoryAllocateInfo.handleTypes = handleType;
if (properties.externalMemoryFeatures &
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV) {
memset(&dedicatedAllocationInfo, 0, sizeof(dedicatedAllocationInfo));
dedicatedAllocationInfo.sType =
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV;
dedicatedAllocationInfo.image = image;
exportMemoryAllocateInfo.pNext = &dedicatedAllocationInfo;
}
memset(&memoryAllocateInfo, 0, sizeof(memoryAllocateInfo));
memoryAllocateInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
memoryAllocateInfo.pNext = &exportMemoryAllocateInfo;
memoryAllocateInfo.allocationSize = imageMemoryRequirements.size;
memoryAllocateInfo.memoryTypeIndex = memoryType;
vkAllocateMemory(device, &memoryAllocateInfo, NULL, &memory);
if (!(properties.externalMemoryFeatures &
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV)) {
vkBindImageMemory(device, image, memory, 0);
}
// Get the external memory opaque FD handle
vkGetMemoryWin32HandleNV(device, memory, &memoryHnd);
VkExportMemoryWin32HandleInfoNV - Specify security attributes and access
rights for Win32 memory handles
Description
If this structure is not present, or if pAttributes is NULL, default
security descriptor values will be used, and child processes created by
the application will not inherit the handle, as described in the MSDN
documentation for “Synchronization Object Security and Access Rights”1.
Further, if the structure is not present, the access rights will be
EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_BIT_NV specifies a valid
NT handle to memory returned by
IDXGIResource1::CreateSharedHandle, or a handle duplicated from
such a handle using DuplicateHandle().