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

diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index 7d1ff642b02aa56639f96720239f34a6ae7db297..4faf15d5fa6df55acd909dcb275dc4c3346c5d46 100644 (file)
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -823,8 +823,7 @@ 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));