#include <xe_drm.h>

Public Attributes
__u64	extensions

__u64	size

__u32	placement

__u32	flags

__u32	vm_id

__u32	handle

__u16	cpu_caching

__u16	pad [3]

__u64	reserved [2]

Detailed Description

struct drm_xe_gem_create - Input of &DRM_IOCTL_XE_GEM_CREATE - A structure for gem creation

The @flags can be:

DRM_XE_GEM_CREATE_FLAG_DEFER_BACKING - Modify the GEM object allocation strategy by deferring physical memory allocation until the object is either bound to a virtual memory region via VM_BIND or accessed by the CPU. As a result, no backing memory is reserved at the time of GEM object creation.
DRM_XE_GEM_CREATE_FLAG_SCANOUT - Indicates that the GEM object is intended for scanout via the display engine. When set, kernel ensures that the allocation is placed in a memory region compatible with the display engine requirements. This may impose restrictions on tiling, alignment, and memory placement to guarantee proper display functionality.
DRM_XE_GEM_CREATE_FLAG_NEEDS_VISIBLE_VRAM - When using VRAM as a possible placement, ensure that the corresponding VRAM allocation will always use the CPU accessible part of VRAM. This is important for small-bar systems (on full-bar systems this gets turned into a noop). Note1: System memory can be used as an extra placement if the kernel should spill the allocation to system memory, if space can't be made available in the CPU accessible part of VRAM (giving the same behaviour as the i915 interface, see I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS). Note2: For clear-color CCS surfaces the kernel needs to read the clear-color value stored in the buffer, and on discrete platforms we need to use VRAM for display surfaces, therefore the kernel requires setting this flag for such objects, otherwise an error is thrown on small-bar systems.
DRM_XE_GEM_CREATE_FLAG_NO_COMPRESSION - Allows userspace to hint that compression (CCS) should be disabled for the buffer being created. This can avoid unnecessary memory operations and CCS state management. On pre-Xe2 platforms, this flag is currently rejected as compression control is not supported via PAT index. On Xe2+ platforms, compression is controlled via PAT entries. If this flag is set, the driver will reject any VM bind that requests a PAT index enabling compression for this BO. Note: On dGPU platforms, there is currently no change in behavior with this flag, but future improvements may leverage it. The current benefit is primarily applicable to iGPU platforms.

@cpu_caching supports the following values:

DRM_XE_GEM_CPU_CACHING_WB - Allocate the pages with write-back caching. On iGPU this can't be used for scanout surfaces. Currently not allowed for objects placed in VRAM.
DRM_XE_GEM_CPU_CACHING_WC - Allocate the pages as write-combined. This is uncached. Scanout surfaces should likely use this. All objects that can be placed in VRAM must use this.

This ioctl supports setting the following properties via the DRM_XE_GEM_CREATE_EXTENSION_SET_PROPERTY extension, which uses the generic &struct drm_xe_ext_set_property:

DRM_XE_GEM_CREATE_SET_PROPERTY_PXP_TYPE - set the type of PXP session this object will be used with. Valid values are listed in enum drm_xe_pxp_session_type. DRM_XE_PXP_TYPE_NONE is the default behavior, so there is no need to explicitly set that. Objects used with session of type DRM_XE_PXP_TYPE_HWDRM will be marked as invalid if a PXP invalidation event occurs after their creation. Attempting to flip an invalid object will cause a black frame to be displayed instead. Submissions with invalid objects mapped in the VM will be rejected.

Member Data Documentation

◆ cpu_caching

__u16 drm_xe_gem_create::cpu_caching

@cpu_caching: The CPU caching mode to select for this object. If mmapping the object the mode selected here will also be used. The exception is when mapping system memory (including data evicted to system) on discrete GPUs. The caching mode selected will then be overridden to DRM_XE_GEM_CPU_CACHING_WB, and coherency between GPU- and CPU is guaranteed. The caching mode of existing CPU-mappings will be updated transparently to user-space clients.

◆ extensions

__u64 drm_xe_gem_create::extensions

@extensions: Pointer to the first extension struct, if any

◆ flags

__u32 drm_xe_gem_create::flags

@flags: Flags for the GEM object, see DRM_XE_GEM_CREATE_FLAG_*

◆ handle

__u32 drm_xe_gem_create::handle

@handle: Returned handle for the object.

Object handles are nonzero.

◆ pad

__u16 drm_xe_gem_create::pad[3]

@pad: MBZ

◆ placement

__u32 drm_xe_gem_create::placement

@placement: A mask of memory instances of where BO can be placed. Each index in this mask refers directly to the struct drm_xe_query_mem_regions' instance, no assumptions should be made about order. The type of each region is described by struct drm_xe_query_mem_regions' mem_class.

◆ reserved

__u64 drm_xe_gem_create::reserved[2]

@reserved: Reserved

◆ size

__u64 drm_xe_gem_create::size

@size: Size of the object to be created, must match region (system or vram) minimum alignment (&min_page_size).

◆ vm_id

__u32 drm_xe_gem_create::vm_id

@vm_id: Attached VM, if any

If a VM is specified, this BO must:

Only ever be bound to that VM.
Cannot be exported as a PRIME fd.

The documentation for this struct was generated from the following file:

XenevaOS/BaseHdr/uapi/drm/xe_drm.h

Public Attributes