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drm/amdgpu: Drop MMIO_REMAP domain bit and keep it Internal

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"AMDGPU_GEM_DOMAIN_MMIO_REMAP" - Never activated as UAPI and it turned
out that this was to inflexible.

Allocate the MMIO_REMAP buffer object as a regular GEM BO and explicitly
move it into the fixed AMDGPU_PL_MMIO_REMAP placement at the TTM level.

This avoids relying on GEM domain bits for MMIO_REMAP, keeps the
placement purely internal, and makes the lifetime and pinning of the
global MMIO_REMAP BO explicit. The BO is pinned in TTM so it cannot be
migrated or evicted.

The corresponding free path relies on normal DRM teardown ordering,
where no further user ioctls can access the global BO once TTM teardown
begins.

v2 (Srini):
- Updated patch title.
- Drop use of AMDGPU_GEM_DOMAIN_MMIO_REMAP in amdgpu_ttm.c. The
  MMIO_REMAP domain bit is removed from UAPI, so keep the MMIO_REMAP BO
  allocation domain-less (bp.domain = 0) and rely on the TTM placement
  (AMDGPU_PL_MMIO_REMAP) for backing/pinning.
- Keep fdinfo/mem-stats visibility for MMIO_REMAP by classifying BOs
  based on bo->tbo.resource->mem_type == AMDGPU_PL_MMIO_REMAP, since the
  domain bit is removed.

v3: Squash patches #1 & #3

Fixes: 0561324837 ("drm/amdgpu/uapi: Introduce AMDGPU_GEM_DOMAIN_MMIO_REMAP")
Fixes: 2a7a794eb8 ("drm/amdgpu/ttm: Allocate/Free 4K MMIO_REMAP Singleton")
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Leo Liu <leo.liu@amd.com>
Cc: Ruijing Dong <ruijing.dong@amd.com>
Cc: David (Ming Qiang) Wu <David.Wu3@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Christian König
2025-12-02 16:12:41 +01:00
committed by Alex Deucher
parent cf3f100cec
commit 96e97a562d
5 changed files with 60 additions and 49 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
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@@ -153,14 +153,6 @@ void amdgpu_bo_placement_from_domain(struct amdgpu_bo *abo, u32 domain)
c++;
}
if (domain & AMDGPU_GEM_DOMAIN_MMIO_REMAP) {
places[c].fpfn = 0;
places[c].lpfn = 0;
places[c].mem_type = AMDGPU_PL_MMIO_REMAP;
places[c].flags = 0;
c++;
}
if (domain & AMDGPU_GEM_DOMAIN_GTT) {
places[c].fpfn = 0;
places[c].lpfn = 0;
@@ -1546,8 +1538,17 @@ u64 amdgpu_bo_gpu_offset_no_check(struct amdgpu_bo *bo)
*/
uint32_t amdgpu_bo_mem_stats_placement(struct amdgpu_bo *bo)
{
uint32_t domain = bo->preferred_domains & AMDGPU_GEM_DOMAIN_MASK;
u32 domain;
/*
* MMIO_REMAP is internal now, so it no longer maps from a userspace
* domain bit. Keep fdinfo/mem-stats visibility by checking the actual
* TTM placement.
*/
if (bo->tbo.resource && bo->tbo.resource->mem_type == AMDGPU_PL_MMIO_REMAP)
return AMDGPU_PL_MMIO_REMAP;
domain = bo->preferred_domains & AMDGPU_GEM_DOMAIN_MASK;
if (!domain)
return TTM_PL_SYSTEM;
@@ -1566,8 +1567,6 @@ uint32_t amdgpu_bo_mem_stats_placement(struct amdgpu_bo *bo)
return AMDGPU_PL_OA;
case AMDGPU_GEM_DOMAIN_DOORBELL:
return AMDGPU_PL_DOORBELL;
case AMDGPU_GEM_DOMAIN_MMIO_REMAP:
return AMDGPU_PL_MMIO_REMAP;
default:
return TTM_PL_SYSTEM;
}