[Intel-gfx] [RFC] drm/i915/selftests: Fix overwriting ggtt

[Niranjana Vishwanathapura]

Looks like vma and gtt mock selftests overwrite the ggtt
initialized by mock_gem_device() by calling intel_gt_assign_ggtt()
and mock_init_ggtt() functions.
The side effect seems to be mock_destroy_device() tries to
release the ggtt already released by mock_fini_ggtt() instead of
releasing the ggtt created by mock_gem_device() function.

I ran into this issue with vm_bind patch series.
https://patchwork.freedesktop.org/series/105879/#rev5

I am fixing the vm_bind patch series by remvoing the vm->root_obj
initialization for ggtt (it is required only for ppgtt upon user
request).

But we need to address the underlying problem.
But with this patch, I am seeing some of the vma and gtt mock
selftests run into other crashes. So, this patch is not complete
and I am missing the big picture here. Hence this RFC.

Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
---
 drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 16 ++--------------
 drivers/gpu/drm/i915/selftests/i915_vma.c     | 16 ++--------------
 2 files changed, 4 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index ea2cf1080979..9b0dae1d1a68 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -1919,30 +1919,18 @@ int i915_gem_gtt_mock_selftests(void)
 		SUBTEST(igt_gtt_insert),
 	};
 	struct drm_i915_private *i915;
-	struct intel_gt *gt;
 	int err;
 
 	i915 = mock_gem_device();
 	if (!i915)
 		return -ENOMEM;
 
-	/* allocate the ggtt */
-	err = intel_gt_assign_ggtt(to_gt(i915));
-	if (err)
-		goto out_put;
-
-	gt = to_gt(i915);
-
-	mock_init_ggtt(gt);
-
-	err = i915_subtests(tests, gt->ggtt);
+	err = i915_subtests(tests, to_gt(i915)->ggtt);
 
 	mock_device_flush(i915);
 	i915_gem_drain_freed_objects(i915);
-	mock_fini_ggtt(gt->ggtt);
-
-out_put:
 	mock_destroy_device(i915);
+
 	return err;
 }
 
diff --git a/drivers/gpu/drm/i915/selftests/i915_vma.c b/drivers/gpu/drm/i915/selftests/i915_vma.c
index 71b52d5efef4..dbe78ed408e5 100644
--- a/drivers/gpu/drm/i915/selftests/i915_vma.c
+++ b/drivers/gpu/drm/i915/selftests/i915_vma.c
@@ -923,30 +923,18 @@ int i915_vma_mock_selftests(void)
 		SUBTEST(igt_vma_partial),
 	};
 	struct drm_i915_private *i915;
-	struct intel_gt *gt;
 	int err;
 
 	i915 = mock_gem_device();
 	if (!i915)
 		return -ENOMEM;
 
-	/* allocate the ggtt */
-	err = intel_gt_assign_ggtt(to_gt(i915));
-	if (err)
-		goto out_put;
-
-	gt = to_gt(i915);
-
-	mock_init_ggtt(gt);
-
-	err = i915_subtests(tests, gt->ggtt);
+	err = i915_subtests(tests, to_gt(i915)->ggtt);
 
 	mock_device_flush(i915);
 	i915_gem_drain_freed_objects(i915);
-	mock_fini_ggtt(gt->ggtt);
-
-out_put:
 	mock_destroy_device(i915);
+
 	return err;
 }
 
-- 
2.21.0.rc0.32.g243a4c7e27