amdgpu_userq_get_doorbell_index() pins any BO passed as doorbell_handle
into the doorbell domain. For a regular BO, TTM moves it with
ttm_bo_move_null() and its contents are lost. Since an importer on the
same device gets the exporter's GEM object, a client can do this to a
buffer another client shared with it.
Reject BOs that were not created in the doorbell domain.
v2: drop the error message, use a local abo variable (Christian)
Fixes: f09c1e6077ab ("drm/amdgpu: generate doorbell index for userqueue")
Signed-off-by: Jesse Zhang <[email protected]>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
index 89e03d3a930c..5a922f283743 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
@@ -469,6 +469,7 @@ amdgpu_userq_get_doorbell_index(struct amdgpu_userq_mgr
*uq_mgr,
u64 doorbell_index;
struct drm_gem_object *gobj;
struct amdgpu_userq_obj *db_obj = db_info->db_obj;
+ struct amdgpu_bo *abo;
int r, db_size;
gobj = drm_gem_object_lookup(filp, db_info->doorbell_handle);
@@ -477,7 +478,17 @@ amdgpu_userq_get_doorbell_index(struct amdgpu_userq_mgr
*uq_mgr,
return -EINVAL;
}
- db_obj->obj = amdgpu_bo_ref(gem_to_amdgpu_bo(gobj));
+ /*
+ * Pinning a regular BO into the doorbell domain would discard its
+ * contents, possibly those of a buffer shared by another client.
+ */
+ abo = gem_to_amdgpu_bo(gobj);
+ if (!(abo->preferred_domains & AMDGPU_GEM_DOMAIN_DOORBELL)) {
+ drm_gem_object_put(gobj);
+ return -EINVAL;
+ }
+
+ db_obj->obj = amdgpu_bo_ref(abo);
drm_gem_object_put(gobj);
r = amdgpu_bo_reserve(db_obj->obj, true);
--
2.50.1
