[PATCH v5] drm/amdgpu: bind BOs when the eviction fence is attached

From: Prerona Ghosh <[email protected]>

DMA-buf imports are created in TTM_PL_SYSTEM and land on the VM idle
list, so nothing binds them for a VM using user queues: amdgpu_vm_validate()
and amdgpu_userq_bo_validate() skip idle BOs, and amdgpu_cs never runs.
AMDGPU_GEM_VA then programs PTEs without AMDGPU_PTE_VALID and the first
GPU access faults.

amdgpu_evf_mgr_attach_fence() is the right place to fix this, but it only
validated while the eviction fence was unsignaled. At amdgpu_gem_object_open()
time the fence is still the permanently signaled stub installed by
amdgpu_evf_mgr_init(); a real fence only appears after amdgpu_evf_mgr_rearm().
Natively created BOs hide the bug because amdgpu_bo_create() already
validated them.

Validate imported BOs even when the fence is signaled, and unwind the
bo_va if that fails.

v3: validate inside amdgpu_gem_object_open (Christian)
v4: fix amdgpu_evf_mgr_attach_fence itself instead (Christian)
v5: restrict the extra validation to imports so that resident and pinned
    BOs are not migrated or failed on every GEM open

Signed-off-by: Prerona Ghosh <[email protected]>
Signed-off-by: Yifan Zhang <[email protected]>
Assisted-by: Claude:claude-opus-5.0
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c | 11 ++++++++---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c            |  9 ++++++++-
 2 files changed, 16 insertions(+), 4 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..c2f9380511a3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
@@ -101,11 +101,16 @@ 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)) {
-
+	/*
+	 * Imports are created in TTM_PL_SYSTEM and this is the only place a VM
+	 * using user queues binds them, so validate those even when the fence
+	 * is already signaled.
+	 */
+	if (!dma_fence_is_signaled(ev_fence) ||
+	    drm_gem_is_imported(&bo->tbo.base)) {
 		amdgpu_bo_placement_from_domain(bo, bo->allowed_domains);
 		ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
-		if (!ret)
+		if (!ret && !dma_fence_is_signaled(ev_fence))
 			dma_resv_add_fence(resv, ev_fence,
 					   DMA_RESV_USAGE_BOOKKEEP);
 	} else {
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index f754a4a3a1c2..3118b3036564 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -264,9 +264,16 @@ static int amdgpu_gem_object_open(struct drm_gem_object *obj,
 	bo_va = amdgpu_vm_bo_find(vm, abo);
 	if (!bo_va) {
 		bo_va = amdgpu_vm_bo_add(adev, vm, abo);
+		if (!bo_va) {
+			r = -ENOMEM;
+			goto out_unlock;
+		}
+
 		r = amdgpu_evf_mgr_attach_fence(&fpriv->evf_mgr, abo);
-		if (r)
+		if (r) {
+			amdgpu_vm_bo_del(adev, bo_va);
 			goto out_unlock;
+		}
 	} else {
 		++bo_va->ref_count;
 	}
-- 
2.43.0