drm/xe: Fix incorrect migration of backed-up object to VRAM

If an object is backed up to shmem it is incorrectly identified
as not having valid data by the move code. This means moving
to VRAM skips the -EMULTIHOP step and the bo is cleared. This
causes all sorts of weird behaviour on DGFX if an already evicted
object is targeted by the shrinker.

Fix this by using ttm_tt_is_swapped() to identify backed-up
objects.

Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/5996
Fixes: 00c8efc3180f ("drm/xe: Add a shrinker for xe bos")
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: <stable@vger.kernel.org> # v6.15+
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://lore.kernel.org/r/20250828134837.5709-1-thomas.hellstrom@linux.intel.com
(cherry picked from commit 1047bd82794a1eab64d643f196d09171ce983f44)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index 1be2415966df2dfce2abff03bfda6fa5f5ebd577..9954bb458ce12d90e59c63b3ab4cc60cab6b95aa 100644 (file)
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -819,8 +819,7 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict,
                return ret;
        }
 
-       tt_has_data = ttm && (ttm_tt_is_populated(ttm) ||
-                             (ttm->page_flags & TTM_TT_FLAG_SWAPPED));
+       tt_has_data = ttm && (ttm_tt_is_populated(ttm) || ttm_tt_is_swapped(ttm));
 
        move_lacks_source = !old_mem || (handle_system_ccs ? (!bo->ccs_cleared) :
                                         (!mem_type_is_vram(old_mem_type) && !tt_has_data));