drivers/gpu/drm/ttm/tests/ttm_bo_test.c

// SPDX-License-Identifier: GPL-2.0 AND MIT
/*
 * Copyright © 2023 Intel Corporation
 */
#include <linux/dma-resv.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/mutex.h>
#include <linux/ww_mutex.h>

#include <drm/ttm/ttm_resource.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/ttm/ttm_tt.h>

#include "ttm_kunit_helpers.h"

#define BO_SIZE		SZ_8K

#ifdef CONFIG_PREEMPT_RT
#define ww_mutex_base_lock(b)			rt_mutex_lock(b)
#else
#define ww_mutex_base_lock(b)			mutex_lock(b)
#endif

struct ttm_bo_test_case {
	const char *description;
	bool interruptible;
	bool no_wait;
};

static const struct ttm_bo_test_case ttm_bo_reserved_cases[] = {
	{
		.description = "Cannot be interrupted and sleeps",
		.interruptible = false,
		.no_wait = false,
	},
	{
		.description = "Cannot be interrupted, locks straight away",
		.interruptible = false,
		.no_wait = true,
	},
	{
		.description = "Can be interrupted, sleeps",
		.interruptible = true,
		.no_wait = false,
	},
};

static void ttm_bo_init_case_desc(const struct ttm_bo_test_case *t,
				  char *desc)
{
	strscpy(desc, t->description, KUNIT_PARAM_DESC_SIZE);
}

KUNIT_ARRAY_PARAM(ttm_bo_reserve, ttm_bo_reserved_cases, ttm_bo_init_case_desc);

static void ttm_bo_reserve_optimistic_no_ticket(struct kunit *test)
{
	const struct ttm_bo_test_case *params = test->param_value;
	struct ttm_buffer_object *bo;
	int err;

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);

	err = ttm_bo_reserve(bo, params->interruptible, params->no_wait, NULL);
	KUNIT_ASSERT_EQ(test, err, 0);

	dma_resv_unlock(bo->base.resv);
}

static void ttm_bo_reserve_locked_no_sleep(struct kunit *test)
{
	struct ttm_buffer_object *bo;
	bool interruptible = false;
	bool no_wait = true;
	int err;

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);

	/* Let's lock it beforehand */
	dma_resv_lock(bo->base.resv, NULL);

	err = ttm_bo_reserve(bo, interruptible, no_wait, NULL);
	dma_resv_unlock(bo->base.resv);

	KUNIT_ASSERT_EQ(test, err, -EBUSY);
}

static void ttm_bo_reserve_no_wait_ticket(struct kunit *test)
{
	struct ttm_buffer_object *bo;
	struct ww_acquire_ctx ctx;
	bool interruptible = false;
	bool no_wait = true;
	int err;

	ww_acquire_init(&ctx, &reservation_ww_class);

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);

	err = ttm_bo_reserve(bo, interruptible, no_wait, &ctx);
	KUNIT_ASSERT_EQ(test, err, -EBUSY);

	ww_acquire_fini(&ctx);
}

static void ttm_bo_reserve_double_resv(struct kunit *test)
{
	struct ttm_buffer_object *bo;
	struct ww_acquire_ctx ctx;
	bool interruptible = false;
	bool no_wait = false;
	int err;

	ww_acquire_init(&ctx, &reservation_ww_class);

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);

	err = ttm_bo_reserve(bo, interruptible, no_wait, &ctx);
	KUNIT_ASSERT_EQ(test, err, 0);

	err = ttm_bo_reserve(bo, interruptible, no_wait, &ctx);

	dma_resv_unlock(bo->base.resv);
	ww_acquire_fini(&ctx);

	KUNIT_ASSERT_EQ(test, err, -EALREADY);
}

/*
 * A test case heavily inspired by ww_test_edeadlk_normal(). It injects
 * a deadlock by manipulating the sequence number of the context that holds
 * dma_resv lock of bo2 so the other context is "wounded" and has to back off
 * (indicated by -EDEADLK). The subtest checks if ttm_bo_reserve() properly
 * propagates that error.
 */
static void ttm_bo_reserve_deadlock(struct kunit *test)
{
	struct ttm_buffer_object *bo1, *bo2;
	struct ww_acquire_ctx ctx1, ctx2;
	bool interruptible = false;
	bool no_wait = false;
	int err;

	bo1 = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);
	bo2 = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);

	ww_acquire_init(&ctx1, &reservation_ww_class);
	ww_mutex_base_lock(&bo2->base.resv->lock.base);

	/* The deadlock will be caught by WW mutex, don't warn about it */
	lock_release(&bo2->base.resv->lock.base.dep_map, 1);

	bo2->base.resv->lock.ctx = &ctx2;
	ctx2 = ctx1;
	ctx2.stamp--; /* Make the context holding the lock younger */

	err = ttm_bo_reserve(bo1, interruptible, no_wait, &ctx1);
	KUNIT_ASSERT_EQ(test, err, 0);

	err = ttm_bo_reserve(bo2, interruptible, no_wait, &ctx1);
	KUNIT_ASSERT_EQ(test, err, -EDEADLK);

	dma_resv_unlock(bo1->base.resv);
	ww_acquire_fini(&ctx1);
}

#if IS_BUILTIN(CONFIG_DRM_TTM_KUNIT_TEST)
struct signal_timer {
	struct timer_list timer;
	struct ww_acquire_ctx *ctx;
};

static void signal_for_ttm_bo_reserve(struct timer_list *t)
{
	struct signal_timer *s_timer = from_timer(s_timer, t, timer);
	struct task_struct *task = s_timer->ctx->task;

	do_send_sig_info(SIGTERM, SEND_SIG_PRIV, task, PIDTYPE_PID);
}

static int threaded_ttm_bo_reserve(void *arg)
{
	struct ttm_buffer_object *bo = arg;
	struct signal_timer s_timer;
	struct ww_acquire_ctx ctx;
	bool interruptible = true;
	bool no_wait = false;
	int err;

	ww_acquire_init(&ctx, &reservation_ww_class);

	/* Prepare a signal that will interrupt the reservation attempt */
	timer_setup_on_stack(&s_timer.timer, &signal_for_ttm_bo_reserve, 0);
	s_timer.ctx = &ctx;

	mod_timer(&s_timer.timer, msecs_to_jiffies(100));

	err = ttm_bo_reserve(bo, interruptible, no_wait, &ctx);

	timer_delete_sync(&s_timer.timer);
	destroy_timer_on_stack(&s_timer.timer);

	ww_acquire_fini(&ctx);

	return err;
}

static void ttm_bo_reserve_interrupted(struct kunit *test)
{
	struct ttm_buffer_object *bo;
	struct task_struct *task;
	int err;

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);

	task = kthread_create(threaded_ttm_bo_reserve, bo, "ttm-bo-reserve");

	if (IS_ERR(task))
		KUNIT_FAIL(test, "Couldn't create ttm bo reserve task\n");

	/* Take a lock so the threaded reserve has to wait */
	mutex_lock(&bo->base.resv->lock.base);

	wake_up_process(task);
	msleep(20);
	err = kthread_stop(task);

	mutex_unlock(&bo->base.resv->lock.base);

	KUNIT_ASSERT_EQ(test, err, -ERESTARTSYS);
}
#endif /* IS_BUILTIN(CONFIG_DRM_TTM_KUNIT_TEST) */

static void ttm_bo_unreserve_basic(struct kunit *test)
{
	struct ttm_test_devices *priv = test->priv;
	struct ttm_buffer_object *bo;
	struct ttm_device *ttm_dev;
	struct ttm_resource *res1, *res2;
	struct ttm_place *place;
	struct ttm_resource_manager *man;
	unsigned int bo_prio = TTM_MAX_BO_PRIORITY - 1;
	u32 mem_type = TTM_PL_SYSTEM;
	int err;

	place = ttm_place_kunit_init(test, mem_type, 0);

	ttm_dev = kunit_kzalloc(test, sizeof(*ttm_dev), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, ttm_dev);

	err = ttm_device_kunit_init(priv, ttm_dev, false, false);
	KUNIT_ASSERT_EQ(test, err, 0);
	priv->ttm_dev = ttm_dev;

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);
	bo->priority = bo_prio;

	err = ttm_resource_alloc(bo, place, &res1);
	KUNIT_ASSERT_EQ(test, err, 0);

	bo->resource = res1;

	/* Add a dummy resource to populate LRU */
	ttm_resource_alloc(bo, place, &res2);

	dma_resv_lock(bo->base.resv, NULL);
	ttm_bo_unreserve(bo);

	man = ttm_manager_type(priv->ttm_dev, mem_type);
	KUNIT_ASSERT_EQ(test,
			list_is_last(&res1->lru.link, &man->lru[bo->priority]), 1);

	ttm_resource_free(bo, &res2);
	ttm_resource_free(bo, &res1);
}

static void ttm_bo_unreserve_pinned(struct kunit *test)
{
	struct ttm_test_devices *priv = test->priv;
	struct ttm_buffer_object *bo;
	struct ttm_device *ttm_dev;
	struct ttm_resource *res1, *res2;
	struct ttm_place *place;
	u32 mem_type = TTM_PL_SYSTEM;
	int err;

	ttm_dev = kunit_kzalloc(test, sizeof(*ttm_dev), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, ttm_dev);

	err = ttm_device_kunit_init(priv, ttm_dev, false, false);
	KUNIT_ASSERT_EQ(test, err, 0);
	priv->ttm_dev = ttm_dev;

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);
	place = ttm_place_kunit_init(test, mem_type, 0);

	dma_resv_lock(bo->base.resv, NULL);
	ttm_bo_pin(bo);

	err = ttm_resource_alloc(bo, place, &res1);
	KUNIT_ASSERT_EQ(test, err, 0);
	bo->resource = res1;

	/* Add a dummy resource to the pinned list */
	err = ttm_resource_alloc(bo, place, &res2);
	KUNIT_ASSERT_EQ(test, err, 0);
	KUNIT_ASSERT_EQ(test,
			list_is_last(&res2->lru.link, &priv->ttm_dev->pinned), 1);

	ttm_bo_unreserve(bo);
	KUNIT_ASSERT_EQ(test,
			list_is_last(&res1->lru.link, &priv->ttm_dev->pinned), 1);

	ttm_resource_free(bo, &res1);
	ttm_resource_free(bo, &res2);
}

static void ttm_bo_unreserve_bulk(struct kunit *test)
{
	struct ttm_test_devices *priv = test->priv;
	struct ttm_lru_bulk_move lru_bulk_move;
	struct ttm_lru_bulk_move_pos *pos;
	struct ttm_buffer_object *bo1, *bo2;
	struct ttm_resource *res1, *res2;
	struct ttm_device *ttm_dev;
	struct ttm_place *place;
	struct dma_resv *resv;
	u32 mem_type = TTM_PL_SYSTEM;
	unsigned int bo_priority = 0;
	int err;

	ttm_lru_bulk_move_init(&lru_bulk_move);

	place = ttm_place_kunit_init(test, mem_type, 0);

	ttm_dev = kunit_kzalloc(test, sizeof(*ttm_dev), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, ttm_dev);

	resv = kunit_kzalloc(test, sizeof(*resv), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, ttm_dev);

	err = ttm_device_kunit_init(priv, ttm_dev, false, false);
	KUNIT_ASSERT_EQ(test, err, 0);
	priv->ttm_dev = ttm_dev;

	dma_resv_init(resv);

	bo1 = ttm_bo_kunit_init(test, test->priv, BO_SIZE, resv);
	bo2 = ttm_bo_kunit_init(test, test->priv, BO_SIZE, resv);

	dma_resv_lock(bo1->base.resv, NULL);
	ttm_bo_set_bulk_move(bo1, &lru_bulk_move);
	dma_resv_unlock(bo1->base.resv);

	err = ttm_resource_alloc(bo1, place, &res1);
	KUNIT_ASSERT_EQ(test, err, 0);
	bo1->resource = res1;

	dma_resv_lock(bo2->base.resv, NULL);
	ttm_bo_set_bulk_move(bo2, &lru_bulk_move);
	dma_resv_unlock(bo2->base.resv);

	err = ttm_resource_alloc(bo2, place, &res2);
	KUNIT_ASSERT_EQ(test, err, 0);
	bo2->resource = res2;

	ttm_bo_reserve(bo1, false, false, NULL);
	ttm_bo_unreserve(bo1);

	pos = &lru_bulk_move.pos[mem_type][bo_priority];
	KUNIT_ASSERT_PTR_EQ(test, res1, pos->last);

	ttm_resource_free(bo1, &res1);
	ttm_resource_free(bo2, &res2);

	dma_resv_fini(resv);
}

static void ttm_bo_put_basic(struct kunit *test)
{
	struct ttm_test_devices *priv = test->priv;
	struct ttm_buffer_object *bo;
	struct ttm_resource *res;
	struct ttm_device *ttm_dev;
	struct ttm_place *place;
	u32 mem_type = TTM_PL_SYSTEM;
	int err;

	place = ttm_place_kunit_init(test, mem_type, 0);

	ttm_dev = kunit_kzalloc(test, sizeof(*ttm_dev), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, ttm_dev);

	err = ttm_device_kunit_init(priv, ttm_dev, false, false);
	KUNIT_ASSERT_EQ(test, err, 0);
	priv->ttm_dev = ttm_dev;

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);
	bo->type = ttm_bo_type_device;

	err = ttm_resource_alloc(bo, place, &res);
	KUNIT_ASSERT_EQ(test, err, 0);
	bo->resource = res;

	dma_resv_lock(bo->base.resv, NULL);
	err = ttm_tt_create(bo, false);
	dma_resv_unlock(bo->base.resv);
	KUNIT_EXPECT_EQ(test, err, 0);

	ttm_bo_put(bo);
}

static const char *mock_name(struct dma_fence *f)
{
	return "kunit-ttm-bo-put";
}

static const struct dma_fence_ops mock_fence_ops = {
	.get_driver_name = mock_name,
	.get_timeline_name = mock_name,
};

static void ttm_bo_put_shared_resv(struct kunit *test)
{
	struct ttm_test_devices *priv = test->priv;
	struct ttm_buffer_object *bo;
	struct dma_resv *external_resv;
	struct dma_fence *fence;
	/* A dummy DMA fence lock */
	spinlock_t fence_lock;
	struct ttm_device *ttm_dev;
	int err;

	ttm_dev = kunit_kzalloc(test, sizeof(*ttm_dev), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, ttm_dev);

	err = ttm_device_kunit_init(priv, ttm_dev, false, false);
	KUNIT_ASSERT_EQ(test, err, 0);
	priv->ttm_dev = ttm_dev;

	external_resv = kunit_kzalloc(test, sizeof(*ttm_dev), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, external_resv);

	dma_resv_init(external_resv);

	fence = kunit_kzalloc(test, sizeof(*fence), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, fence);

	spin_lock_init(&fence_lock);
	dma_fence_init(fence, &mock_fence_ops, &fence_lock, 0, 0);

	dma_resv_lock(external_resv, NULL);
	dma_resv_reserve_fences(external_resv, 1);
	dma_resv_add_fence(external_resv, fence, DMA_RESV_USAGE_BOOKKEEP);
	dma_resv_unlock(external_resv);

	dma_fence_signal(fence);

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);
	bo->type = ttm_bo_type_device;
	bo->base.resv = external_resv;

	ttm_bo_put(bo);
}

static void ttm_bo_pin_basic(struct kunit *test)
{
	struct ttm_test_devices *priv = test->priv;
	struct ttm_buffer_object *bo;
	struct ttm_device *ttm_dev;
	unsigned int no_pins = 3;
	int err;

	ttm_dev = kunit_kzalloc(test, sizeof(*ttm_dev), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, ttm_dev);

	err = ttm_device_kunit_init(priv, ttm_dev, false, false);
	KUNIT_ASSERT_EQ(test, err, 0);
	priv->ttm_dev = ttm_dev;

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);

	for (int i = 0; i < no_pins; i++) {
		dma_resv_lock(bo->base.resv, NULL);
		ttm_bo_pin(bo);
		dma_resv_unlock(bo->base.resv);
	}

	KUNIT_ASSERT_EQ(test, bo->pin_count, no_pins);
}

static void ttm_bo_pin_unpin_resource(struct kunit *test)
{
	struct ttm_test_devices *priv = test->priv;
	struct ttm_lru_bulk_move lru_bulk_move;
	struct ttm_lru_bulk_move_pos *pos;
	struct ttm_buffer_object *bo;
	struct ttm_resource *res;
	struct ttm_device *ttm_dev;
	struct ttm_place *place;
	u32 mem_type = TTM_PL_SYSTEM;
	unsigned int bo_priority = 0;
	int err;

	ttm_lru_bulk_move_init(&lru_bulk_move);

	place = ttm_place_kunit_init(test, mem_type, 0);

	ttm_dev = kunit_kzalloc(test, sizeof(*ttm_dev), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, ttm_dev);

	err = ttm_device_kunit_init(priv, ttm_dev, false, false);
	KUNIT_ASSERT_EQ(test, err, 0);
	priv->ttm_dev = ttm_dev;

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);

	err = ttm_resource_alloc(bo, place, &res);
	KUNIT_ASSERT_EQ(test, err, 0);
	bo->resource = res;

	dma_resv_lock(bo->base.resv, NULL);
	ttm_bo_set_bulk_move(bo, &lru_bulk_move);
	ttm_bo_pin(bo);
	dma_resv_unlock(bo->base.resv);

	pos = &lru_bulk_move.pos[mem_type][bo_priority];

	KUNIT_ASSERT_EQ(test, bo->pin_count, 1);
	KUNIT_ASSERT_NULL(test, pos->first);
	KUNIT_ASSERT_NULL(test, pos->last);

	dma_resv_lock(bo->base.resv, NULL);
	ttm_bo_unpin(bo);
	dma_resv_unlock(bo->base.resv);

	KUNIT_ASSERT_PTR_EQ(test, res, pos->last);
	KUNIT_ASSERT_EQ(test, bo->pin_count, 0);

	ttm_resource_free(bo, &res);
}

static void ttm_bo_multiple_pin_one_unpin(struct kunit *test)
{
	struct ttm_test_devices *priv = test->priv;
	struct ttm_lru_bulk_move lru_bulk_move;
	struct ttm_lru_bulk_move_pos *pos;
	struct ttm_buffer_object *bo;
	struct ttm_resource *res;
	struct ttm_device *ttm_dev;
	struct ttm_place *place;
	u32 mem_type = TTM_PL_SYSTEM;
	unsigned int bo_priority = 0;
	int err;

	ttm_lru_bulk_move_init(&lru_bulk_move);

	place = ttm_place_kunit_init(test, mem_type, 0);

	ttm_dev = kunit_kzalloc(test, sizeof(*ttm_dev), GFP_KERNEL);
	KUNIT_ASSERT_NOT_NULL(test, ttm_dev);

	err = ttm_device_kunit_init(priv, ttm_dev, false, false);
	KUNIT_ASSERT_EQ(test, err, 0);
	priv->ttm_dev = ttm_dev;

	bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);

	err = ttm_resource_alloc(bo, place, &res);
	KUNIT_ASSERT_EQ(test, err, 0);
	bo->resource = res;

	dma_resv_lock(bo->base.resv, NULL);
	ttm_bo_set_bulk_move(bo, &lru_bulk_move);

	/* Multiple pins */
	ttm_bo_pin(bo);
	ttm_bo_pin(bo);

	dma_resv_unlock(bo->base.resv);

	pos = &lru_bulk_move.pos[mem_type][bo_priority];

	KUNIT_ASSERT_EQ(test, bo->pin_count, 2);
	KUNIT_ASSERT_NULL(test, pos->first);
	KUNIT_ASSERT_NULL(test, pos->last);

	dma_resv_lock(bo->base.resv, NULL);
	ttm_bo_unpin(bo);
	dma_resv_unlock(bo->base.resv);

	KUNIT_ASSERT_EQ(test, bo->pin_count, 1);
	KUNIT_ASSERT_NULL(test, pos->first);
	KUNIT_ASSERT_NULL(test, pos->last);

	dma_resv_lock(bo->base.resv, NULL);
	ttm_bo_unpin(bo);
	dma_resv_unlock(bo->base.resv);

	ttm_resource_free(bo, &res);
}

static struct kunit_case ttm_bo_test_cases[] = {
	KUNIT_CASE_PARAM(ttm_bo_reserve_optimistic_no_ticket,
			 ttm_bo_reserve_gen_params),
	KUNIT_CASE(ttm_bo_reserve_locked_no_sleep),
	KUNIT_CASE(ttm_bo_reserve_no_wait_ticket),
	KUNIT_CASE(ttm_bo_reserve_double_resv),
#if IS_BUILTIN(CONFIG_DRM_TTM_KUNIT_TEST)
	KUNIT_CASE(ttm_bo_reserve_interrupted),
#endif
	KUNIT_CASE(ttm_bo_reserve_deadlock),
	KUNIT_CASE(ttm_bo_unreserve_basic),
	KUNIT_CASE(ttm_bo_unreserve_pinned),
	KUNIT_CASE(ttm_bo_unreserve_bulk),
	KUNIT_CASE(ttm_bo_put_basic),
	KUNIT_CASE(ttm_bo_put_shared_resv),
	KUNIT_CASE(ttm_bo_pin_basic),
	KUNIT_CASE(ttm_bo_pin_unpin_resource),
	KUNIT_CASE(ttm_bo_multiple_pin_one_unpin),
	{}
};

static struct kunit_suite ttm_bo_test_suite = {
	.name = "ttm_bo",
	.init = ttm_test_devices_init,
	.exit = ttm_test_devices_fini,
	.test_cases = ttm_bo_test_cases,
};

kunit_test_suites(&ttm_bo_test_suite);

MODULE_DESCRIPTION("KUnit tests for ttm_bo APIs");
MODULE_LICENSE("GPL and additional rights");