[PATCH v1 7/7] drm/xe/kunit: Test VRAM pool allocation

["Piórkowski, Piotr" <piotr.piorkowski@intel.com>]

From: Piotr Piórkowski <piotr.piorkowski@intel.com>

Exercise default pool setup, pool splitting and partition limits, and
TTM placement range narrowing.

Assisted-by: Claude Opus 5.5
Signed-off-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
---
 drivers/gpu/drm/xe/tests/xe_vram.c | 155 +++++++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_vram.c       |   4 +
 2 files changed, 159 insertions(+)
 create mode 100644 drivers/gpu/drm/xe/tests/xe_vram.c

diff --git a/drivers/gpu/drm/xe/tests/xe_vram.c b/drivers/gpu/drm/xe/tests/xe_vram.c
new file mode 100644
index 0000000000000..043c40b6bb0a9
--- /dev/null
+++ b/drivers/gpu/drm/xe/tests/xe_vram.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0 AND MIT
+/*
+ * Copyright © 2026 Intel Corporation
+ */
+
+#include <kunit/test.h>
+
+#include "xe_kunit_helpers.h"
+#include "xe_pci_test.h"
+
+static int xe_vram_test_init(struct kunit *test)
+{
+	struct xe_pci_fake_data fake = {
+		.platform = XE_BATTLEMAGE,
+		.graphics_verx100 = 2001,
+	};
+
+	test->priv = &fake;
+	xe_kunit_helper_xe_device_test_init(test);
+
+	return 0;
+}
+
+static struct xe_vram_pool *tile_pool(struct kunit *test, struct xe_device *xe)
+{
+	struct xe_vram_region *vram = xe_vram_region_alloc_tile(xe, 0);
+	struct xe_vram_pool *pool;
+
+	KUNIT_ASSERT_NOT_NULL(test, vram);
+	vram->usable_size = SZ_64M;
+	vram->io_size = SZ_64M;
+	pool = xe_vram_region_default_pool(vram);
+	pool->size = SZ_64M;
+	pool->purpose = XE_VRAM_POOL_GENERAL;
+	vram->num_partitions = 1;
+
+	return pool;
+}
+
+static void kernel_pool_defaults_to_general(struct kunit *test)
+{
+	struct xe_device *xe = test->priv;
+	struct xe_vram_pool *general = tile_pool(test, xe);
+	struct xe_tile *tile = &xe->tiles[0];
+
+	tile->mem.vram = general;
+	tile->mem.kernel_vram = NULL;
+
+	KUNIT_ASSERT_EQ(test, xe_vram_tile_alloc_kernel(tile), 0);
+	KUNIT_EXPECT_PTR_EQ(test, tile->mem.kernel_vram, tile->mem.vram);
+}
+
+static void partition_carve(struct kunit *test)
+{
+	struct xe_device *xe = test->priv;
+	struct xe_vram_pool *general = tile_pool(test, xe);
+	struct xe_vram_region *vram = general->region;
+	struct xe_vram_pool *kernel0 = &vram->partitions[1];
+
+	KUNIT_EXPECT_PTR_EQ(test, xe_vram_pool_create(vram, XE_VRAM_POOL_KERNEL, 0), NULL);
+	KUNIT_EXPECT_PTR_EQ(test, xe_vram_pool_create(vram, XE_VRAM_POOL_KERNEL, SZ_1M), NULL);
+	KUNIT_EXPECT_PTR_EQ(test, xe_vram_pool_create(vram, XE_VRAM_POOL_KERNEL, SZ_64M), NULL);
+	KUNIT_EXPECT_EQ(test, vram->num_partitions, 1u);
+
+	KUNIT_ASSERT_NOT_NULL(test, xe_vram_pool_create(vram, XE_VRAM_POOL_KERNEL, SZ_8M));
+	KUNIT_ASSERT_EQ(test, vram->num_partitions, 2u);
+	KUNIT_EXPECT_EQ(test, kernel0->purpose, XE_VRAM_POOL_KERNEL);
+	KUNIT_EXPECT_EQ(test, kernel0->offset, 0ull);
+	KUNIT_EXPECT_EQ(test, kernel0->size, (u64)SZ_8M);
+	KUNIT_EXPECT_EQ(test, general->purpose, XE_VRAM_POOL_GENERAL);
+	KUNIT_EXPECT_EQ(test, general->offset, (u64)SZ_8M);
+	KUNIT_EXPECT_EQ(test, general->size, (u64)(SZ_64M - SZ_8M));
+
+	/* Both partitions keep sharing the region, its manager and its placement */
+	KUNIT_EXPECT_PTR_EQ(test, kernel0->region, vram);
+	KUNIT_EXPECT_PTR_EQ(test, general->region, vram);
+	KUNIT_EXPECT_EQ(test, vram->placement, (u32)XE_PL_VRAM0);
+
+	KUNIT_EXPECT_EQ(test, xe_vram_pool_usable_size(kernel0), (resource_size_t)SZ_8M);
+	KUNIT_EXPECT_EQ(test, xe_vram_pool_usable_size(general),
+			(resource_size_t)(SZ_64M - SZ_8M));
+}
+
+static void partition_limit(struct kunit *test)
+{
+	struct xe_device *xe = test->priv;
+	struct xe_vram_pool *general = tile_pool(test, xe);
+	struct xe_vram_region *vram = general->region;
+	struct xe_vram_pool *pool;
+	unsigned int i;
+
+	for (i = 1; i < XE_VRAM_MAX_PARTITIONS; i++) {
+		pool = xe_vram_pool_create(vram, XE_VRAM_POOL_KERNEL, SZ_2M);
+		KUNIT_ASSERT_NOT_NULL(test, pool);
+	}
+
+	KUNIT_EXPECT_EQ(test, vram->num_partitions, XE_VRAM_MAX_PARTITIONS);
+	KUNIT_EXPECT_PTR_EQ(test,
+			    xe_vram_pool_create(vram, XE_VRAM_POOL_KERNEL, SZ_2M),
+			    NULL);
+}
+
+static void pool_place(struct kunit *test)
+{
+	struct xe_device *xe = test->priv;
+	struct xe_vram_pool *general = tile_pool(test, xe);
+	struct xe_vram_region *vram = general->region;
+	struct xe_vram_pool *kernel = &vram->partitions[1];
+	struct ttm_place place = {};
+
+	/* A pool spanning the region only resolves to its placement */
+	xe_vram_pool_place(general, &place);
+	KUNIT_EXPECT_EQ(test, place.mem_type, (u32)XE_PL_VRAM0);
+	KUNIT_EXPECT_EQ(test, place.fpfn, 0u);
+	KUNIT_EXPECT_EQ(test, place.lpfn, 0u);
+
+	KUNIT_ASSERT_NOT_NULL(test, xe_vram_pool_create(vram, XE_VRAM_POOL_KERNEL, SZ_8M));
+
+	place = (struct ttm_place) {};
+	xe_vram_pool_place(kernel, &place);
+	KUNIT_EXPECT_EQ(test, place.fpfn, 0u);
+	KUNIT_EXPECT_EQ(test, place.lpfn, SZ_8M >> PAGE_SHIFT);
+
+	place = (struct ttm_place) {};
+	xe_vram_pool_place(general, &place);
+	KUNIT_EXPECT_EQ(test, place.fpfn, SZ_8M >> PAGE_SHIFT);
+	KUNIT_EXPECT_EQ(test, place.lpfn, SZ_64M >> PAGE_SHIFT);
+
+	/* A caller supplied range, e.g. the CPU visible one, is only narrowed */
+	place = (struct ttm_place) { .lpfn = SZ_4M >> PAGE_SHIFT };
+	xe_vram_pool_place(kernel, &place);
+	KUNIT_EXPECT_EQ(test, place.fpfn, 0u);
+	KUNIT_EXPECT_EQ(test, place.lpfn, SZ_4M >> PAGE_SHIFT);
+
+	place = (struct ttm_place) { .lpfn = SZ_32M >> PAGE_SHIFT };
+	xe_vram_pool_place(general, &place);
+	KUNIT_EXPECT_EQ(test, place.fpfn, SZ_8M >> PAGE_SHIFT);
+	KUNIT_EXPECT_EQ(test, place.lpfn, SZ_32M >> PAGE_SHIFT);
+}
+
+static struct kunit_case xe_vram_tests[] = {
+	KUNIT_CASE(kernel_pool_defaults_to_general),
+	KUNIT_CASE(partition_carve),
+	KUNIT_CASE(partition_limit),
+	KUNIT_CASE(pool_place),
+	{}
+};
+
+static struct kunit_suite xe_vram_test_suite = {
+	.name = "xe_vram",
+	.test_cases = xe_vram_tests,
+	.init = xe_vram_test_init,
+};
+
+kunit_test_suite(xe_vram_test_suite);
diff --git a/drivers/gpu/drm/xe/xe_vram.c b/drivers/gpu/drm/xe/xe_vram.c
index 1df4f2514afc0..cfc1dc77b2cb4 100644
--- a/drivers/gpu/drm/xe/xe_vram.c
+++ b/drivers/gpu/drm/xe/xe_vram.c
@@ -639,6 +639,10 @@ resource_size_t xe_vram_region_actual_physical_size(const struct xe_vram_region
 }
 EXPORT_SYMBOL_IF_KUNIT(xe_vram_region_actual_physical_size);
 
+#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
+#include "tests/xe_vram.c"
+#endif
+
 #if IS_ENABLED(CONFIG_DRM_XE_DEBUG_MEM)
 static void memtest_bo_cleanup(void *arg)
 {
-- 
2.34.1