From: Prerona Ghosh <[email protected]> DMA-buf imports are created in TTM_PL_SYSTEM and land on the VM idle list, so neither amdgpu_vm_validate() nor amdgpu_userq_bo_validate() ever binds them. Only the BO list of a command submission does, and a VM using user queues never runs amdgpu_cs. AMDGPU_GEM_VA then programs PTEs from a TTM_PL_SYSTEM resource, i.e. without AMDGPU_PTE_VALID, and the first GPU access faults.
amdgpu_evf_mgr_attach_fence() is supposed to cover exactly that case from amdgpu_gem_object_open(), but it validates only when the current eviction fence is unsignaled. At open time that is normally not true: amdgpu_evf_mgr_init() installs the stub fence, which is permanently signaled, and a real fence only appears once amdgpu_evf_mgr_rearm() runs from the resume worker. So an import opened before the client creates its first user queue - or between an eviction and the resume - is left unbound. Natively created BOs hide the problem because amdgpu_bo_create() already validated them into their domain. Validate unconditionally and keep the signaled check only for adding the fence, which is all it was needed for. A BO that cannot be bound now fails the ioctl rather than handing out a handle that only maps to faulting PTEs. v3: validate inside amdgpu_gem_object_open (Christian) v4: fix amdgpu_evf_mgr_attach_fence itself instead (Christian) Signed-off-by: Prerona Ghosh <[email protected]> Signed-off-by: Yifan Zhang <[email protected]> Assisted-by: Claude:claude-opus-5.0 --- .../drm/amd/amdgpu/amdgpu_eviction_fence.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c index 4c5e38dea4c2..69a7f573134f 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c @@ -101,16 +101,15 @@ int amdgpu_evf_mgr_attach_fence(struct amdgpu_eviction_fence_mgr *evf_mgr, struct dma_resv *resv = bo->tbo.base.resv; int ret; - if (!dma_fence_is_signaled(ev_fence)) { - - amdgpu_bo_placement_from_domain(bo, bo->allowed_domains); - ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); - if (!ret) - dma_resv_add_fence(resv, ev_fence, - DMA_RESV_USAGE_BOOKKEEP); - } else { - ret = 0; - } + /* + * Validate even when the fence is already signaled: DMA-buf imports are + * created in TTM_PL_SYSTEM and this is the only place a VM using user + * queues binds them. + */ + amdgpu_bo_placement_from_domain(bo, bo->allowed_domains); + ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); + if (!ret && !dma_fence_is_signaled(ev_fence)) + dma_resv_add_fence(resv, ev_fence, DMA_RESV_USAGE_BOOKKEEP); dma_fence_put(ev_fence); return ret; -- 2.43.0
