[Intel-xe] [PATCH 3/4] drm/xe/selftests: restart GT after xe_bo_restore_kernel()

[Matthew Auld]

Test seems to be failing badly after calling xe_bo_restore_kernel().
Taking a snapshot of the CTB and copying back a potentially old version
seems risky, depending on what might have been inflight. Also it seems
snapshotting the ADS object and copying back results in serious
breakage. Normally when calling xe_bo_restore_kernel() we always fully
restart the GT, which re-intializes such things.  We could potentially
skip saving and restoring such objects in xe_bo_evict_all() however
seems quite fragile not to also restart the GT. Try to do that here by
triggering a GT reset.

Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Cc: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/tests/xe_bo.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/xe/tests/xe_bo.c b/drivers/gpu/drm/xe/tests/xe_bo.c
index 6aad1443b00e..21c6dfef8dc7 100644
--- a/drivers/gpu/drm/xe/tests/xe_bo.c
+++ b/drivers/gpu/drm/xe/tests/xe_bo.c
@@ -220,7 +220,21 @@ static int evict_test_run_gt(struct xe_device *xe, struct xe_gt *gt, struct kuni
 			goto cleanup_all;
 		}
 
+		xe_gt_sanitize(gt);
 		err = xe_bo_restore_kernel(xe);
+		/*
+		 * Snapshotting the CTB and copying back a potentially old
+		 * version seems risky, depending on what might have been
+		 * inflight. Also it seems snapshotting the ADS object and
+		 * copying back results in serious breakage. Normally when
+		 * calling xe_bo_restore_kernel() we always fully restart the
+		 * GT, which re-intializes such things.  We could potentially
+		 * skip saving and restoring such objects in xe_bo_evict_all()
+		 * however seems quite fragile not to also restart the GT. Try
+		 * to do that here by triggering a GT reset.
+		 */
+		xe_gt_reset_async(gt);
+		flush_work(&gt->reset.worker);
 		if (err) {
 			KUNIT_FAIL(test, "restore kernel err=%pe\n",
 				   ERR_PTR(err));
-- 
2.41.0