[PATCH v8 01/24] drm/xe: reference VM from PT BOs

[Matthew Brost <matthew.brost@intel.com>]

PT BOs share the VM's dma-resv and therefore must keep the VM alive
until all PT BOs are destroyed.
 
Take a VM reference from PT BOs to ensure the shared dma-resv remains
valid for the lifetime of the BOs. Scope the change to PT BOs rather
than all kernel BOs to minimize risk and avoid extending VM lifetimes
unnecessarily.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Maarten Lankhorst <dev@lankhorst.se>
Reviewed-by: Francois Dugast <francois.dugast@intel.com>
---
 drivers/gpu/drm/xe/xe_bo.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index f2ab9bf43a86..6921b6967330 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -1879,7 +1879,7 @@ static void xe_ttm_bo_destroy(struct ttm_buffer_object *ttm_bo)
 		xe_drm_client_remove_bo(bo);
 #endif
 
-	if (bo->vm && xe_bo_is_user(bo))
+	if (bo->vm && (xe_bo_is_user(bo) || bo->flags & XE_BO_FLAG_PAGETABLE))
 		xe_vm_put(bo->vm);
 
 	if (bo->parent_obj)
@@ -2575,7 +2575,7 @@ __xe_bo_create_locked(struct xe_device *xe,
 	 * by having all the vm's bo refereferences released at vm close
 	 * time.
 	 */
-	if (vm && xe_bo_is_user(bo))
+	if (vm && (xe_bo_is_user(bo) || bo->flags & XE_BO_FLAG_PAGETABLE))
 		xe_vm_get(vm);
 	bo->vm = vm;
 
-- 
2.34.1