platform/x86/intel/pmt: KUNIT test for PMT Enhanced Discovery API

Adds a KUNIT test for the intel_pmt_get_regions_by_feature() API.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Link: https://lore.kernel.org/r/20250703022832.1302928-16-david.e.box@linux.intel.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

drivers/platform/x86/intel/pmt/Kconfig

@@ -51,3 +51,17 @@ config INTEL_PMT_DISCOVERY
 
 	  To compile this driver as a module, choose M here: the module
 	  will be called pmt_discovery.
+
+config INTEL_PMT_KUNIT_TEST
+	tristate "KUnit tests for Intel PMT driver"
+	depends on INTEL_PMT_DISCOVERY
+	depends on KUNIT
+	help
+	  Enable this option to compile and run a suite of KUnit tests for the Intel
+	  Platform Monitoring Technology (PMT) driver. These tests are designed to
+	  validate the driver's functionality, error handling, and overall stability,
+	  helping developers catch regressions and ensure code quality during changes.
+
+	  This option is intended for development and testing environments. It is
+	  recommended to disable it in production builds. To compile this driver as a
+	  module, choose M here: the module will be called pmt-discovery-kunit.

drivers/platform/x86/intel/pmt/Makefile

@@ -12,3 +12,5 @@ obj-$(CONFIG_INTEL_PMT_CRASHLOG)	+= pmt_crashlog.o
 pmt_crashlog-y				:= crashlog.o
 obj-$(CONFIG_INTEL_PMT_DISCOVERY)	+= pmt_discovery.o
 pmt_discovery-y				:= discovery.o features.o
+obj-$(CONFIG_INTEL_PMT_KUNIT_TEST)	+= pmt-discovery-kunit.o
+pmt-discovery-kunit-y			:= discovery-kunit.o

drivers/platform/x86/intel/pmt/discovery-kunit.c

@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Platform Monitory Technology Discovery KUNIT tests
+ *
+ * Copyright (c) 2025, Intel Corporation.
+ * All Rights Reserved.
+ */
+
+#include <kunit/test.h>
+#include <linux/err.h>
+#include <linux/intel_pmt_features.h>
+#include <linux/intel_vsec.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#define PMT_FEATURE_COUNT (FEATURE_MAX + 1)
+
+static void
+validate_pmt_regions(struct kunit *test, struct pmt_feature_group *feature_group, int feature_id)
+{
+	int i;
+
+	kunit_info(test, "Feature ID %d [%s] has %d regions.\n", feature_id,
+		   pmt_feature_names[feature_id], feature_group->count);
+
+	for (i = 0; i < feature_group->count; i++) {
+		struct telemetry_region *region = &feature_group->regions[i];
+
+		kunit_info(test, "  - Region %d: cdie_mask=%u, package_id=%u, partition=%u, segment=%u,",
+			   i, region->plat_info.cdie_mask, region->plat_info.package_id,
+			   region->plat_info.partition, region->plat_info.segment);
+		kunit_info(test, "\t\tbus=%u, device=%u, function=%u, guid=0x%x,",
+			   region->plat_info.bus_number, region->plat_info.device_number,
+			   region->plat_info.function_number, region->guid);
+		kunit_info(test, "\t\taddr=%p, size=%lu, num_rmids=%u", region->addr, region->size,
+			   region->num_rmids);
+
+
+		KUNIT_ASSERT_GE(test, region->plat_info.cdie_mask, 0);
+		KUNIT_ASSERT_GE(test, region->plat_info.package_id, 0);
+		KUNIT_ASSERT_GE(test, region->plat_info.partition, 0);
+		KUNIT_ASSERT_GE(test, region->plat_info.segment, 0);
+		KUNIT_ASSERT_GE(test, region->plat_info.bus_number, 0);
+		KUNIT_ASSERT_GE(test, region->plat_info.device_number, 0);
+		KUNIT_ASSERT_GE(test, region->plat_info.function_number, 0);
+
+		KUNIT_ASSERT_NE(test, region->guid, 0);
+
+		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, (__force const void *)region->addr);
+	}
+}
+
+static void linebreak(struct kunit *test)
+{
+	kunit_info(test, "*****************************************************************************\n");
+}
+
+static void test_intel_pmt_get_regions_by_feature(struct kunit *test)
+{
+	struct pmt_feature_group *feature_group;
+	int num_available = 0;
+	int feature_id;
+
+	/* Iterate through all possible feature IDs */
+	for (feature_id = 1; feature_id < PMT_FEATURE_COUNT; feature_id++, linebreak(test)) {
+		const char *name;
+
+		if (!pmt_feature_id_is_valid(feature_id))
+			continue;
+
+		name = pmt_feature_names[feature_id];
+
+		feature_group = intel_pmt_get_regions_by_feature(feature_id);
+		if (IS_ERR(feature_group)) {
+			if (PTR_ERR(feature_group) == -ENOENT)
+				kunit_warn(test, "intel_pmt_get_regions_by_feature() reporting feature %d [%s] is not present.\n",
+					   feature_id, name);
+			else
+				kunit_warn(test, "intel_pmt_get_regions_by_feature() returned error %ld while attempt to lookup %d [%s].\n",
+					   PTR_ERR(feature_group), feature_id, name);
+
+			continue;
+		}
+
+		if (!feature_group) {
+			kunit_warn(test, "Feature ID %d: %s is not available.\n", feature_id, name);
+			continue;
+		}
+
+		num_available++;
+
+		validate_pmt_regions(test, feature_group, feature_id);
+
+		intel_pmt_put_feature_group(feature_group);
+	}
+
+	if (num_available == 0)
+		kunit_warn(test, "No PMT region groups were available for any feature ID (0-10).\n");
+}
+
+static struct kunit_case intel_pmt_discovery_test_cases[] = {
+	KUNIT_CASE(test_intel_pmt_get_regions_by_feature),
+	{}
+};
+
+static struct kunit_suite intel_pmt_discovery_test_suite = {
+	.name = "pmt_discovery_test",
+	.test_cases = intel_pmt_discovery_test_cases,
+};
+
+kunit_test_suite(intel_pmt_discovery_test_suite);
+
+MODULE_IMPORT_NS("INTEL_PMT_DISCOVERY");
+MODULE_AUTHOR("David E. Box <david.e.box@linux.intel.com>");
+MODULE_DESCRIPTION("Intel PMT Discovery KUNIT test driver");
+MODULE_LICENSE("GPL");