Re: [PATCH v12 06/10] drm/ttm/tests: Add tests with mock resource managers

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On Wed, 2024-05-15 at 13:24 +0200, Karolina Stolarek wrote:
> Add mock resource manager to test ttm_bo_validate() with non-system
> placements. Update KConfig entry to enable DRM Buddy allocator, used
> by the mock manager. Update move function to do more than just assign
> a resource.
> 
> Signed-off-by: Karolina Stolarek <karolina.stolarek@intel.com>
> Tested-by: Somalapuram, Amaranath <asomalap@amd.com>
> ---
>  drivers/gpu/drm/Kconfig                       |   1 +
>  drivers/gpu/drm/ttm/tests/.kunitconfig        |   1 +
>  drivers/gpu/drm/ttm/tests/Makefile            |   1 +
>  .../gpu/drm/ttm/tests/ttm_bo_validate_test.c  | 274
> ++++++++++++++++++
>  drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c |  38 ++-
>  drivers/gpu/drm/ttm/tests/ttm_mock_manager.c  | 207 +++++++++++++
>  drivers/gpu/drm/ttm/tests/ttm_mock_manager.h  |  31 ++
>  7 files changed, 551 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/gpu/drm/ttm/tests/ttm_mock_manager.c
>  create mode 100644 drivers/gpu/drm/ttm/tests/ttm_mock_manager.h
> 
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 026444eeb5c6..4ba16501dbf7 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -234,6 +234,7 @@ config DRM_TTM_KUNIT_TEST
>          default n
>          depends on DRM && KUNIT && MMU && (UML || COMPILE_TEST)
>          select DRM_TTM
> +        select DRM_BUDDY
>          select DRM_EXPORT_FOR_TESTS if m
>          select DRM_KUNIT_TEST_HELPERS
>          default KUNIT_ALL_TESTS
> diff --git a/drivers/gpu/drm/ttm/tests/.kunitconfig
> b/drivers/gpu/drm/ttm/tests/.kunitconfig
> index 1ae1ffabd51e..772f0e1f4103 100644
> --- a/drivers/gpu/drm/ttm/tests/.kunitconfig
> +++ b/drivers/gpu/drm/ttm/tests/.kunitconfig
> @@ -1,3 +1,4 @@
>  CONFIG_KUNIT=y
>  CONFIG_DRM=y
>  CONFIG_DRM_TTM_KUNIT_TEST=y
> +CONFIG_DRM_BUDDY=y

Is this strictly needed when CONFIG_DRM_TTM_KUNIT_TEST is selected?
Wouldn't that be enabled implicitly?

> diff --git a/drivers/gpu/drm/ttm/tests/Makefile
> b/drivers/gpu/drm/ttm/tests/Makefile
> index 2e5ed63fb414..f3149de77541 100644
> --- a/drivers/gpu/drm/ttm/tests/Makefile
> +++ b/drivers/gpu/drm/ttm/tests/Makefile
> @@ -7,4 +7,5 @@ obj-$(CONFIG_DRM_TTM_KUNIT_TEST) += \
>          ttm_tt_test.o \
>          ttm_bo_test.o \
>          ttm_bo_validate_test.o \
> +        ttm_mock_manager.o \
>          ttm_kunit_helpers.o
> diff --git a/drivers/gpu/drm/ttm/tests/ttm_bo_validate_test.c
> b/drivers/gpu/drm/ttm/tests/ttm_bo_validate_test.c
> index a5520b0631a3..8b62d95b8ab8 100644
> --- a/drivers/gpu/drm/ttm/tests/ttm_bo_validate_test.c
> +++ b/drivers/gpu/drm/ttm/tests/ttm_bo_validate_test.c
> @@ -8,12 +8,15 @@
>  #include <drm/ttm/ttm_tt.h>
>  
>  #include "ttm_kunit_helpers.h"
> +#include "ttm_mock_manager.h"
>  
>  #define BO_SIZE		SZ_4K
> +#define MANAGER_SIZE	SZ_1M
>  
>  struct ttm_bo_validate_test_case {
>  	const char *description;
>  	enum ttm_bo_type bo_type;
> +	uint32_t mem_type;

Please use u32 instead of unit32_t in new code. The unit32_t usage in
TTM is a remnant from when much of the drm- and ttm code was shared
with *bsd. Same in a couple of places below.

>  	bool with_ttm;
>  };
>  
> @@ -102,6 +105,49 @@ static void ttm_bo_init_reserved_sys_man(struct
> kunit *test)
>  	ttm_bo_put(bo);
>  }
>  
> +static void ttm_bo_init_reserved_mock_man(struct kunit *test)
> +{
> +	const struct ttm_bo_validate_test_case *params = test-
> >param_value;
> +	enum ttm_bo_type bo_type = params->bo_type;
> +	struct ttm_test_devices *priv = test->priv;
> +	uint32_t size = ALIGN(BO_SIZE, PAGE_SIZE);
> +	struct ttm_operation_ctx ctx = { };
> +	struct ttm_placement *placement;
> +	uint32_t mem_type = TTM_PL_VRAM;
> +	struct ttm_buffer_object *bo;
> +	struct ttm_place *place;
> +	int err;
> +
> +	ttm_mock_manager_init(priv->ttm_dev, mem_type,
> MANAGER_SIZE);
> +
> +	bo = kunit_kzalloc(test, sizeof(*bo), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_NULL(test, bo);
> +
> +	place = ttm_place_kunit_init(test, mem_type, 0);
> +	placement = ttm_placement_kunit_init(test, place, 1);
> +
> +	drm_gem_private_object_init(priv->drm, &bo->base, size);
> +
> +	err = ttm_bo_init_reserved(priv->ttm_dev, bo, bo_type,
> placement,
> +				   PAGE_SIZE, &ctx, NULL, NULL,
> +				   &dummy_ttm_bo_destroy);
> +	dma_resv_unlock(bo->base.resv);
> +
> +	KUNIT_EXPECT_EQ(test, err, 0);
> +	KUNIT_EXPECT_EQ(test, kref_read(&bo->kref), 1);
> +	KUNIT_EXPECT_PTR_EQ(test, bo->bdev, priv->ttm_dev);
> +	KUNIT_EXPECT_EQ(test, bo->type, bo_type);
> +	KUNIT_EXPECT_EQ(test, ctx.bytes_moved, size);
> +
> +	if (bo_type != ttm_bo_type_kernel)
> +		KUNIT_EXPECT_TRUE(test,
> +				  drm_mm_node_allocated(&bo-
> >base.vma_node.vm_node));
> +
> +	ttm_resource_free(bo, &bo->resource);
> +	ttm_bo_put(bo);
> +	ttm_mock_manager_fini(priv->ttm_dev, mem_type);
> +}
> +
>  static void ttm_bo_init_reserved_resv(struct kunit *test)
>  {
>  	enum ttm_bo_type bo_type = ttm_bo_type_device;
> @@ -136,6 +182,51 @@ static void ttm_bo_init_reserved_resv(struct
> kunit *test)
>  	ttm_bo_put(bo);
>  }
>  
> +static void ttm_bo_validate_basic(struct kunit *test)
> +{
> +	const struct ttm_bo_validate_test_case *params = test-
> >param_value;
> +	uint32_t fst_mem = TTM_PL_SYSTEM, snd_mem = TTM_PL_VRAM;
> +	struct ttm_operation_ctx ctx_init = { }, ctx_val = { };
> +	struct ttm_placement *fst_placement, *snd_placement;
> +	struct ttm_test_devices *priv = test->priv;
> +	struct ttm_place *fst_place, *snd_place;
> +	uint32_t size = ALIGN(SZ_8K, PAGE_SIZE);
> +	struct ttm_buffer_object *bo;
> +	int err;
> +
> +	ttm_mock_manager_init(priv->ttm_dev, snd_mem, MANAGER_SIZE);
> +
> +	fst_place = ttm_place_kunit_init(test, fst_mem, 0);
> +	fst_placement = ttm_placement_kunit_init(test, fst_place,
> 1);
> +
> +	bo = kunit_kzalloc(test, sizeof(*bo), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_NULL(test, bo);
> +
> +	drm_gem_private_object_init(priv->drm, &bo->base, size);
> +
> +	err = ttm_bo_init_reserved(priv->ttm_dev, bo, params-
> >bo_type,
> +				   fst_placement, PAGE_SIZE,
> &ctx_init, NULL,
> +				   NULL, &dummy_ttm_bo_destroy);
> +	KUNIT_EXPECT_EQ(test, err, 0);
> +
> +	snd_place = ttm_place_kunit_init(test, snd_mem,
> DRM_BUDDY_TOPDOWN_ALLOCATION);
> +	snd_placement = ttm_placement_kunit_init(test, snd_place,
> 1);
> +
> +	err = ttm_bo_validate(bo, snd_placement, &ctx_val);
> +	dma_resv_unlock(bo->base.resv);
> +
> +	KUNIT_EXPECT_EQ(test, err, 0);
> +	KUNIT_EXPECT_EQ(test, ctx_val.bytes_moved, bo->base.size);
> +	KUNIT_EXPECT_NOT_NULL(test, bo->ttm);
> +	KUNIT_EXPECT_TRUE(test, ttm_tt_is_populated(bo->ttm));
> +	KUNIT_EXPECT_EQ(test, bo->resource->mem_type, snd_mem);
> +	KUNIT_EXPECT_EQ(test, bo->resource->placement,
> +			DRM_BUDDY_TOPDOWN_ALLOCATION);
> +
> +	ttm_bo_put(bo);
> +	ttm_mock_manager_fini(priv->ttm_dev, snd_mem);
> +}
> +
>  static void ttm_bo_validate_invalid_placement(struct kunit *test)
>  {
>  	enum ttm_bo_type bo_type = ttm_bo_type_device;
> @@ -162,6 +253,36 @@ static void
> ttm_bo_validate_invalid_placement(struct kunit *test)
>  	ttm_bo_put(bo);
>  }
>  
> +static void ttm_bo_validate_failed_alloc(struct kunit *test)
> +{
> +	enum ttm_bo_type bo_type = ttm_bo_type_device;
> +	struct ttm_test_devices *priv = test->priv;
> +	uint32_t size = ALIGN(BO_SIZE, PAGE_SIZE);
> +	struct ttm_operation_ctx ctx = { };
> +	struct ttm_placement *placement;
> +	uint32_t mem_type = TTM_PL_VRAM;
> +	struct ttm_buffer_object *bo;
> +	struct ttm_place *place;
> +	int err;
> +
> +	bo = ttm_bo_kunit_init(test, test->priv, size, NULL);
> +	bo->type = bo_type;
> +
> +	ttm_bad_manager_init(priv->ttm_dev, mem_type, MANAGER_SIZE);
> +
> +	place = ttm_place_kunit_init(test, mem_type, 0);
> +	placement = ttm_placement_kunit_init(test, place, 1);
> +
> +	ttm_bo_reserve(bo, false, false, NULL);
> +	err = ttm_bo_validate(bo, placement, &ctx);
> +	dma_resv_unlock(bo->base.resv);
> +
> +	KUNIT_EXPECT_EQ(test, err, -ENOMEM);
> +
> +	ttm_bo_put(bo);
> +	ttm_bad_manager_fini(priv->ttm_dev, mem_type);
> +}
> +
>  static void ttm_bo_validate_pinned(struct kunit *test)
>  {
>  	enum ttm_bo_type bo_type = ttm_bo_type_device;
> @@ -193,11 +314,164 @@ static void ttm_bo_validate_pinned(struct
> kunit *test)
>  	ttm_bo_put(bo);
>  }
>  
> +static const struct ttm_bo_validate_test_case ttm_mem_type_cases[] =
> {
> +	{
> +		.description = "System manager",
> +		.mem_type = TTM_PL_SYSTEM,
> +	},
> +	{
> +		.description = "VRAM manager",
> +		.mem_type = TTM_PL_VRAM,
> +	},
> +};
> +
> +KUNIT_ARRAY_PARAM(ttm_bo_validate_mem, ttm_mem_type_cases,
> +		  ttm_bo_validate_case_desc);
> +
> +static void ttm_bo_validate_same_placement(struct kunit *test)
> +{
> +	const struct ttm_bo_validate_test_case *params = test-
> >param_value;
> +	struct ttm_operation_ctx ctx_init = { }, ctx_val = { };
> +	struct ttm_test_devices *priv = test->priv;
> +	uint32_t size = ALIGN(BO_SIZE, PAGE_SIZE);
> +	struct ttm_placement *placement;
> +	struct ttm_buffer_object *bo;
> +	struct ttm_place *place;
> +	int err;
> +
> +	place = ttm_place_kunit_init(test, params->mem_type, 0);
> +	placement = ttm_placement_kunit_init(test, place, 1);
> +
> +	if (params->mem_type != TTM_PL_SYSTEM)
> +		ttm_mock_manager_init(priv->ttm_dev, params-
> >mem_type, MANAGER_SIZE);
> +
> +	bo = kunit_kzalloc(test, sizeof(*bo), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_NULL(test, bo);
> +
> +	drm_gem_private_object_init(priv->drm, &bo->base, size);
> +
> +	err = ttm_bo_init_reserved(priv->ttm_dev, bo, params-
> >bo_type,
> +				   placement, PAGE_SIZE, &ctx_init,
> NULL,
> +				   NULL, &dummy_ttm_bo_destroy);
> +	KUNIT_EXPECT_EQ(test, err, 0);
> +
> +	err = ttm_bo_validate(bo, placement, &ctx_val);
> +	dma_resv_unlock(bo->base.resv);
> +
> +	KUNIT_EXPECT_EQ(test, err, 0);
> +	KUNIT_EXPECT_EQ(test, ctx_val.bytes_moved, 0);
> +
> +	ttm_bo_put(bo);
> +
> +	if (params->mem_type != TTM_PL_SYSTEM)
> +		ttm_mock_manager_fini(priv->ttm_dev, params-
> >mem_type);
> +}
> +
> +static void ttm_bo_validate_busy_placement(struct kunit *test)
> +{
> +	uint32_t fst_mem = TTM_PL_VRAM, snd_mem = TTM_PL_VRAM + 1;
> +	struct ttm_operation_ctx ctx_init = { }, ctx_val = { };
> +	struct ttm_placement *placement_init, *placement_val;
> +	enum ttm_bo_type bo_type = ttm_bo_type_device;
> +	struct ttm_test_devices *priv = test->priv;
> +	uint32_t size = ALIGN(BO_SIZE, PAGE_SIZE);
> +	struct ttm_place *init_place, places[2];
> +	struct ttm_resource_manager *man;
> +	struct ttm_buffer_object *bo;
> +	int err;
> +
> +	ttm_bad_manager_init(priv->ttm_dev, fst_mem, MANAGER_SIZE);
> +	ttm_mock_manager_init(priv->ttm_dev, snd_mem, MANAGER_SIZE);
> +
> +	init_place = ttm_place_kunit_init(test, TTM_PL_SYSTEM, 0);
> +	placement_init = ttm_placement_kunit_init(test, init_place,
> 1);
> +
> +	bo = kunit_kzalloc(test, sizeof(*bo), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_NULL(test, bo);
> +
> +	drm_gem_private_object_init(priv->drm, &bo->base, size);
> +
> +	err = ttm_bo_init_reserved(priv->ttm_dev, bo, bo_type,
> placement_init,
> +				   PAGE_SIZE, &ctx_init, NULL, NULL,
> +				   &dummy_ttm_bo_destroy);
> +	KUNIT_EXPECT_EQ(test, err, 0);
> +
> +	places[0] = (struct ttm_place){ .mem_type = fst_mem, .flags
> = TTM_PL_FLAG_DESIRED };
> +	places[1] = (struct ttm_place){ .mem_type = snd_mem, .flags
> = TTM_PL_FLAG_FALLBACK };
> +	placement_val = ttm_placement_kunit_init(test, places, 2);
> +
> +	err = ttm_bo_validate(bo, placement_val, &ctx_val);
> +	dma_resv_unlock(bo->base.resv);
> +
> +	man = ttm_manager_type(priv->ttm_dev, snd_mem);
> +
> +	KUNIT_EXPECT_EQ(test, err, 0);
> +	KUNIT_EXPECT_EQ(test, ctx_val.bytes_moved, bo->base.size);
> +	KUNIT_EXPECT_EQ(test, bo->resource->mem_type, snd_mem);
> +	KUNIT_ASSERT_TRUE(test, list_is_singular(&man->lru[bo-
> >priority]));
> +
> +	ttm_bo_put(bo);
> +	ttm_bad_manager_fini(priv->ttm_dev, fst_mem);
> +	ttm_mock_manager_fini(priv->ttm_dev, snd_mem);
> +}
> +
> +static void ttm_bo_validate_multihop(struct kunit *test)
> +{
> +	const struct ttm_bo_validate_test_case *params = test-
> >param_value;
> +	struct ttm_operation_ctx ctx_init = { }, ctx_val = { };
> +	struct ttm_placement *placement_init, *placement_val;
> +	uint32_t fst_mem = TTM_PL_VRAM, tmp_mem = TTM_PL_TT,
> +		 final_mem = TTM_PL_SYSTEM;
> +	struct ttm_test_devices *priv = test->priv;
> +	struct ttm_place *fst_place, *final_place;
> +	uint32_t size = ALIGN(BO_SIZE, PAGE_SIZE);
> +	struct ttm_buffer_object *bo;
> +	int err;
> +
> +	ttm_mock_manager_init(priv->ttm_dev, fst_mem, MANAGER_SIZE);
> +	ttm_mock_manager_init(priv->ttm_dev, tmp_mem, MANAGER_SIZE);
> +
> +	fst_place = ttm_place_kunit_init(test, fst_mem, 0);
> +	placement_init = ttm_placement_kunit_init(test, fst_place,
> 1);
> +
> +	bo = kunit_kzalloc(test, sizeof(*bo), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_NULL(test, bo);
> +
> +	drm_gem_private_object_init(priv->drm, &bo->base, size);
> +
> +	err = ttm_bo_init_reserved(priv->ttm_dev, bo, params-
> >bo_type,
> +				   placement_init, PAGE_SIZE,
> &ctx_init, NULL,
> +				   NULL, &dummy_ttm_bo_destroy);
> +	KUNIT_EXPECT_EQ(test, err, 0);
> +
> +	final_place = ttm_place_kunit_init(test, final_mem, 0);
> +	placement_val = ttm_placement_kunit_init(test, final_place,
> 1);
> +
> +	err = ttm_bo_validate(bo, placement_val, &ctx_val);
> +	dma_resv_unlock(bo->base.resv);
> +
> +	KUNIT_EXPECT_EQ(test, err, 0);
> +	KUNIT_EXPECT_EQ(test, ctx_val.bytes_moved, size * 2);
> +	KUNIT_EXPECT_EQ(test, bo->resource->mem_type, final_mem);
> +
> +	ttm_bo_put(bo);
> +
> +	ttm_mock_manager_fini(priv->ttm_dev, fst_mem);
> +	ttm_mock_manager_fini(priv->ttm_dev, tmp_mem);
> +}
> +
>  static struct kunit_case ttm_bo_validate_test_cases[] = {
>  	KUNIT_CASE_PARAM(ttm_bo_init_reserved_sys_man,
> ttm_bo_types_gen_params),
> +	KUNIT_CASE_PARAM(ttm_bo_init_reserved_mock_man,
> ttm_bo_types_gen_params),
>  	KUNIT_CASE(ttm_bo_init_reserved_resv),
> +	KUNIT_CASE_PARAM(ttm_bo_validate_basic,
> ttm_bo_types_gen_params),
>  	KUNIT_CASE(ttm_bo_validate_invalid_placement),
> +	KUNIT_CASE_PARAM(ttm_bo_validate_same_placement,
> +			 ttm_bo_validate_mem_gen_params),
> +	KUNIT_CASE(ttm_bo_validate_failed_alloc),
>  	KUNIT_CASE(ttm_bo_validate_pinned),
> +	KUNIT_CASE(ttm_bo_validate_busy_placement),
> +	KUNIT_CASE_PARAM(ttm_bo_validate_multihop,
> ttm_bo_types_gen_params),
>  	{}
>  };
>  
> diff --git a/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
> b/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
> index 2f590bae53f8..2a2585b37118 100644
> --- a/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
> +++ b/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
> @@ -27,8 +27,42 @@ static int mock_move(struct ttm_buffer_object *bo,
> bool evict,
>  		     struct ttm_resource *new_mem,
>  		     struct ttm_place *hop)
>  {
> -	bo->resource = new_mem;
> -	return 0;
> +	struct ttm_resource *old_mem = bo->resource;
> +	int ret;
> +
> +	if (!old_mem || (old_mem->mem_type == TTM_PL_SYSTEM && !bo-
> >ttm)) {
> +		ttm_bo_move_null(bo, new_mem);
> +		return 0;
> +	}
> +
> +	if (bo->resource->mem_type == TTM_PL_VRAM &&
> +	    new_mem->mem_type == TTM_PL_SYSTEM) {
> +		hop->mem_type = TTM_PL_TT;
> +		hop->flags = TTM_PL_FLAG_TEMPORARY;
> +		hop->fpfn = 0;
> +		hop->lpfn = 0;
> +		return -EMULTIHOP;
> +	}
> +
> +	if (old_mem->mem_type == TTM_PL_SYSTEM &&
> +	    new_mem->mem_type == TTM_PL_TT) {
> +		ttm_bo_move_null(bo, new_mem);
> +		return 0;
> +	}
> +
> +	if (old_mem->mem_type == TTM_PL_TT &&
> +	    new_mem->mem_type == TTM_PL_SYSTEM) {
> +		ret = ttm_bo_wait_ctx(bo, ctx);

We're not doing any accelerated move here, so ttm_bo_move_null() should
be sufficient also in this case?

> +
> +		if (ret)
> +			return ret;
> +
> +		ttm_resource_free(bo, &bo->resource);
> +		ttm_bo_assign_mem(bo, new_mem);
> +		return 0;
> +	}
> +
> +	return ttm_bo_move_memcpy(bo, ctx, new_mem);

Do we hit this move_memcpy()? Since the mock manager doesn't actually
reserve any memory to manager, I'd expect this to run into problems?



>  }
>  
>  struct ttm_device_funcs ttm_dev_funcs = {
> diff --git a/drivers/gpu/drm/ttm/tests/ttm_mock_manager.c
> b/drivers/gpu/drm/ttm/tests/ttm_mock_manager.c
> new file mode 100644
> index 000000000000..eb9dca1de1a2
> --- /dev/null
> +++ b/drivers/gpu/drm/ttm/tests/ttm_mock_manager.c
> @@ -0,0 +1,207 @@
> +// SPDX-License-Identifier: GPL-2.0 AND MIT
> +/*
> + * Copyright © 2023 Intel Corporation
> + */
> +#include <drm/ttm/ttm_resource.h>
> +#include <drm/ttm/ttm_device.h>
> +#include <drm/ttm/ttm_placement.h>
> +
> +#include "ttm_mock_manager.h"
> +
> +static inline struct ttm_mock_manager *
> +to_mock_mgr(struct ttm_resource_manager *man)
> +{
> +	return container_of(man, struct ttm_mock_manager, man);
> +}
> +
> +static inline struct ttm_mock_resource *
> +to_mock_mgr_resource(struct ttm_resource *res)
> +{
> +	return container_of(res, struct ttm_mock_resource, base);
> +}
> +
> +static int ttm_mock_manager_alloc(struct ttm_resource_manager *man,
> +				  struct ttm_buffer_object *bo,
> +				  const struct ttm_place *place,
> +				  struct ttm_resource **res)
> +{
> +	struct ttm_mock_manager *manager = to_mock_mgr(man);
> +	struct ttm_mock_resource *mock_res;
> +	struct drm_buddy *mm = &manager->mm;
> +	uint64_t lpfn, fpfn, alloc_size;
> +	int err;
> +
> +	mock_res = kzalloc(sizeof(*mock_res), GFP_KERNEL);
> +
> +	if (!mock_res)
> +		return -ENOMEM;
> +
> +	fpfn = 0;
> +	lpfn = man->size;
> +
> +	ttm_resource_init(bo, place, &mock_res->base);
> +	INIT_LIST_HEAD(&mock_res->blocks);
> +
> +	if (place->flags & TTM_PL_FLAG_TOPDOWN)
> +		mock_res->flags |= DRM_BUDDY_TOPDOWN_ALLOCATION;
> +
> +	if (place->flags & TTM_PL_FLAG_CONTIGUOUS)
> +		mock_res->flags |= DRM_BUDDY_CONTIGUOUS_ALLOCATION;
> +
> +	alloc_size = (uint64_t)mock_res->base.size;
> +	mutex_lock(&manager->lock);
> +	err = drm_buddy_alloc_blocks(mm, fpfn, lpfn, alloc_size,
> +				     manager->default_page_size,
> +				     &mock_res->blocks,
> +				     mock_res->flags);
> +
> +	if (err)
> +		goto error_free_blocks;
> +	mutex_unlock(&manager->lock);
> +
> +	*res = &mock_res->base;
> +	return 0;
> +
> +error_free_blocks:
> +	drm_buddy_free_list(mm, &mock_res->blocks, 0);
> +	ttm_resource_fini(man, &mock_res->base);
> +	mutex_unlock(&manager->lock);
> +
> +	return err;
> +}
> +
> +static void ttm_mock_manager_free(struct ttm_resource_manager *man,
> +				  struct ttm_resource *res)
> +{
> +	struct ttm_mock_manager *manager = to_mock_mgr(man);
> +	struct ttm_mock_resource *mock_res =
> to_mock_mgr_resource(res);
> +	struct drm_buddy *mm = &manager->mm;
> +
> +	mutex_lock(&manager->lock);
> +	drm_buddy_free_list(mm, &mock_res->blocks, 0);
> +	mutex_unlock(&manager->lock);
> +
> +	ttm_resource_fini(man, res);
> +	kfree(mock_res);
> +}
> +
> +static const struct ttm_resource_manager_func ttm_mock_manager_funcs
> = {
> +	.alloc = ttm_mock_manager_alloc,
> +	.free = ttm_mock_manager_free,
> +};
> +
> +int ttm_mock_manager_init(struct ttm_device *bdev, uint32_t
> mem_type, uint32_t size)
> +{
> +	struct ttm_mock_manager *manager;
> +	struct ttm_resource_manager *base;
> +	int err;
> +
> +	manager = kzalloc(sizeof(*manager), GFP_KERNEL);
> +	if (!manager)
> +		return -ENOMEM;
> +
> +	mutex_init(&manager->lock);
> +
> +	err = drm_buddy_init(&manager->mm, size, PAGE_SIZE);
> +
> +	if (err) {
> +		kfree(manager);
> +		return err;
> +	}
> +
> +	manager->default_page_size = PAGE_SIZE;
> +	base = &manager->man;
> +	base->func = &ttm_mock_manager_funcs;
> +	base->use_tt = true;
> +
> +	ttm_resource_manager_init(base, bdev, size);
> +	ttm_set_driver_manager(bdev, mem_type, base);
> +	ttm_resource_manager_set_used(base, true);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(ttm_mock_manager_init);
> +
> +void ttm_mock_manager_fini(struct ttm_device *bdev, uint32_t
> mem_type)
> +{
> +	struct ttm_resource_manager *man;
> +	struct ttm_mock_manager *mock_man;
> +	int err;
> +
> +	man = ttm_manager_type(bdev, mem_type);
> +	mock_man = to_mock_mgr(man);
> +
> +	err = ttm_resource_manager_evict_all(bdev, man);
> +	if (err)
> +		return;
> +
> +	ttm_resource_manager_set_used(man, false);
> +
> +	mutex_lock(&mock_man->lock);
> +	drm_buddy_fini(&mock_man->mm);
> +	mutex_unlock(&mock_man->lock);
> +
> +	ttm_set_driver_manager(bdev, mem_type, NULL);
> +}
> +EXPORT_SYMBOL_GPL(ttm_mock_manager_fini);
> +
> +static int ttm_bad_manager_alloc(struct ttm_resource_manager *man,
> +				 struct ttm_buffer_object *bo,
> +				 const struct ttm_place *place,
> +				 struct ttm_resource **res)
> +{
> +	return -ENOSPC;
> +}
> +
> +static void ttm_bad_manager_free(struct ttm_resource_manager *man,
> +				 struct ttm_resource *res)
> +{
> +}
> +
> +static bool ttm_bad_manager_compatible(struct ttm_resource_manager
> *man,
> +				       struct ttm_resource *res,
> +				       const struct ttm_place
> *place,
> +				       size_t size)
> +{
> +	return true;
> +}
> +
> +static const struct ttm_resource_manager_func ttm_bad_manager_funcs
> = {
> +	.alloc = ttm_bad_manager_alloc,
> +	.free = ttm_bad_manager_free,
> +	.compatible = ttm_bad_manager_compatible
> +};
> +
> +int ttm_bad_manager_init(struct ttm_device *bdev, uint32_t mem_type,
> +			 uint32_t size)
> +{
> +	struct ttm_resource_manager *man;
> +
> +	man = kzalloc(sizeof(*man), GFP_KERNEL);
> +	if (!man)
> +		return -ENOMEM;
> +
> +	man->func = &ttm_bad_manager_funcs;
> +
> +	ttm_resource_manager_init(man, bdev, size);
> +	ttm_set_driver_manager(bdev, mem_type, man);
> +	ttm_resource_manager_set_used(man, true);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(ttm_bad_manager_init);
> +
> +void ttm_bad_manager_fini(struct ttm_device *bdev, uint32_t
> mem_type)
> +{
> +	struct ttm_resource_manager *man;
> +
> +	man = ttm_manager_type(bdev, mem_type);
> +
> +	ttm_resource_manager_set_used(man, false);
> +	ttm_set_driver_manager(bdev, mem_type, NULL);
> +
> +	kfree(man);
> +}
> +EXPORT_SYMBOL_GPL(ttm_bad_manager_fini);
> +
> +MODULE_LICENSE("GPL");

When the module is dual-licensed IIRC the correct option to use here is
"GPL and additional rights"

> diff --git a/drivers/gpu/drm/ttm/tests/ttm_mock_manager.h
> b/drivers/gpu/drm/ttm/tests/ttm_mock_manager.h
> new file mode 100644
> index 000000000000..d2db9de9d876
> --- /dev/null
> +++ b/drivers/gpu/drm/ttm/tests/ttm_mock_manager.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: GPL-2.0 AND MIT */
> +/*
> + * Copyright © 2023 Intel Corporation
> + */
> +#ifndef TTM_MOCK_MANAGER_H
> +#define TTM_MOCK_MANAGER_H
> +
> +#include <drm/drm_buddy.h>
> +
> +struct ttm_mock_manager {
> +	struct ttm_resource_manager man;
> +	struct drm_buddy mm;
> +	uint64_t default_page_size;
> +	/* protects allocations of mock buffer objects */
> +	struct mutex lock;
> +};
> +
> +struct ttm_mock_resource {
> +	struct ttm_resource base;
> +	struct list_head blocks;
> +	unsigned long flags;
> +};
> +
> +int ttm_mock_manager_init(struct ttm_device *bdev, uint32_t
> mem_type,
> +			  uint32_t size);
> +int ttm_bad_manager_init(struct ttm_device *bdev, uint32_t mem_type,
> +			 uint32_t size);
> +void ttm_mock_manager_fini(struct ttm_device *bdev, uint32_t
> mem_type);
> +void ttm_bad_manager_fini(struct ttm_device *bdev, uint32_t
> mem_type);
> +
> +#endif // TTM_MOCK_MANAGER_H

Thanks,
Thomas