Commit 9d290ab0 authored by Piotr Piórkowski's avatar Piotr Piórkowski Committed by Michal Wajdeczko
Browse files

drm/xe: Introduce new BO flag XE_BO_FLAG_FORCE_USER_VRAM 



When using a separate VRAM region for kernel allocations,
some kernel structures, such as context userspace data,
should not reside in the VRAM region dedicated to the kernel.
The VRAM kernel region is intended only for allocations necessary
for driver operation. Allocations created via ioctl are long-lived
and not easily evictable. If this region runs out of space,
there may not be a fallback, which could cause failures.
To prevent this, add a new BO flag that explicitly forces the BO to be
allocated in the general-purpose VRAM region accessible to userspace,
avoiding the kernel-only VRAM region.

v2:
 - update commit message (Matthew)

Signed-off-by: default avatarPiotr Piórkowski <piotr.piorkowski@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Signed-off-by: default avatarMichal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://lore.kernel.org/r/20251003162619.1984236-3-piotr.piorkowski@intel.com
parent db7dde99

drivers/gpu/drm/xe/xe_bo.c

+4 −4
Original line number Diff line number Diff line
@@ -226,14 +226,14 @@ static u8 vram_bo_flag_to_tile_id(struct xe_device *xe, u32 vram_bo_flag) 
	return __ffs(vram_bo_flag >> (__ffs(XE_BO_FLAG_VRAM0) - 1)) - 1;

}



static u32 bo_vram_flags_to_vram_placement(struct xe_device *xe, u32 vram_flag,

static u32 bo_vram_flags_to_vram_placement(struct xe_device *xe, u32 bo_flags, u32 vram_flag,

					   enum ttm_bo_type type)

{

	u8 tile_id = vram_bo_flag_to_tile_id(xe, vram_flag);



	xe_assert(xe, tile_id < xe->info.tile_count);



	if (type == ttm_bo_type_kernel)

	if (type == ttm_bo_type_kernel && !(bo_flags & XE_BO_FLAG_FORCE_USER_VRAM))

		return xe->tiles[tile_id].mem.kernel_vram->placement;

	else

		return xe->tiles[tile_id].mem.vram->placement;
@@ -276,7 +276,7 @@ static void try_add_vram(struct xe_device *xe, struct xe_bo *bo, 
	u32 vram_flag;



	for_each_set_bo_vram_flag(vram_flag, bo_flags) {

		u32 pl = bo_vram_flags_to_vram_placement(xe, vram_flag, type);

		u32 pl = bo_vram_flags_to_vram_placement(xe, bo_flags, vram_flag, type);



		add_vram(xe, bo, bo->placements, bo_flags, pl, c);

	}
@@ -2275,7 +2275,7 @@ static int __xe_bo_fixed_placement(struct xe_device *xe, 
	if (flags & XE_BO_FLAG_STOLEN)

		place->mem_type = XE_PL_STOLEN;

	else

		place->mem_type = bo_vram_flags_to_vram_placement(xe, vram_flag, type);

		place->mem_type = bo_vram_flags_to_vram_placement(xe, flags, vram_flag, type);



	bo->placement = (struct ttm_placement) {

		.num_placement = 1,

drivers/gpu/drm/xe/xe_bo.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ 
#define XE_BO_FLAG_GGTT2		BIT(22)

#define XE_BO_FLAG_GGTT3		BIT(23)

#define XE_BO_FLAG_CPU_ADDR_MIRROR	BIT(24)

#define XE_BO_FLAG_FORCE_USER_VRAM	BIT(25)



/* this one is trigger internally only */

#define XE_BO_FLAG_INTERNAL_TEST	BIT(30)