Re: [PATCH 33/33] arm_mpam: Add kunit tests for props_mismatch()

Fenghua Yu <fenghuay@xxxxxxxxxx> · Tue, 2 Sep 2025 09:59:02 -0700

Hi, James,

On 8/22/25 08:30, James Morse wrote:
When features are mismatched between MSC the way features are combined
to the class determines whether resctrl can support this SoC.

Add some tests to illustrate the sort of thing that is expected to
work, and those that must be removed.

Signed-off-by: James Morse <james.morse@xxxxxxx>
---
  drivers/resctrl/mpam_internal.h     |   8 +-
  drivers/resctrl/test_mpam_devices.c | 322 ++++++++++++++++++++++++++++
  2 files changed, 329 insertions(+), 1 deletion(-)
[SNIP]

diff --git a/drivers/resctrl/test_mpam_devices.c b/drivers/resctrl/test_mpam_devices.c
index 8e9d6c88171c..ef39696e7ff8 100644
--- a/drivers/resctrl/test_mpam_devices.c
+++ b/drivers/resctrl/test_mpam_devices.c
@@ -4,6 +4,326 @@
  
  #include <kunit/test.h>
  
+/*
+ * This test catches fields that aren't being sanitised - but can't tell you
+ * which one...
+ */
+static void test__props_mismatch(struct kunit *test)
+{
+	struct mpam_props parent = { 0 };
+	struct mpam_props child;
+
+	memset(&child, 0xff, sizeof(child));
+	__props_mismatch(&parent, &child, false);
+
+	memset(&child, 0, sizeof(child));
+	KUNIT_EXPECT_EQ(test, memcmp(&parent, &child, sizeof(child)), 0);
+
+	memset(&child, 0xff, sizeof(child));
+	__props_mismatch(&parent, &child, true);
+
+	KUNIT_EXPECT_EQ(test, memcmp(&parent, &child, sizeof(child)), 0);
+}
+
+static void test_mpam_enable_merge_features(struct kunit *test)
+{
+	/* o/` How deep is your stack? o/` */
+	struct list_head fake_classes_list;
+	struct mpam_class fake_class = { 0 };
+	struct mpam_component fake_comp1 = { 0 };
+	struct mpam_component fake_comp2 = { 0 };
+	struct mpam_vmsc fake_vmsc1 = { 0 };
+	struct mpam_vmsc fake_vmsc2 = { 0 };
+	struct mpam_msc fake_msc1 = { 0 };
+	struct mpam_msc fake_msc2 = { 0 };
+	struct mpam_msc_ris fake_ris1 = { 0 };
+	struct mpam_msc_ris fake_ris2 = { 0 };
+	struct platform_device fake_pdev = { 0 };
+
+#define RESET_FAKE_HIEARCHY()	do {				\
+	INIT_LIST_HEAD(&fake_classes_list);			\
+								\
+	memset(&fake_class, 0, sizeof(fake_class));		\
+	fake_class.level = 3;					\
+	fake_class.type = MPAM_CLASS_CACHE;			\
+	INIT_LIST_HEAD_RCU(&fake_class.components);		\
+	INIT_LIST_HEAD(&fake_class.classes_list);		\
+								\
+	memset(&fake_comp1, 0, sizeof(fake_comp1));		\
+	memset(&fake_comp2, 0, sizeof(fake_comp2));		\
+	fake_comp1.comp_id = 1;					\
+	fake_comp2.comp_id = 2;					\
+	INIT_LIST_HEAD(&fake_comp1.vmsc);			\
+	INIT_LIST_HEAD(&fake_comp1.class_list);			\
+	INIT_LIST_HEAD(&fake_comp2.vmsc);			\
+	INIT_LIST_HEAD(&fake_comp2.class_list);			\
+								\
+	memset(&fake_vmsc1, 0, sizeof(fake_vmsc1));		\
+	memset(&fake_vmsc2, 0, sizeof(fake_vmsc2));		\
+	INIT_LIST_HEAD(&fake_vmsc1.ris);			\
+	INIT_LIST_HEAD(&fake_vmsc1.comp_list);			\
+	fake_vmsc1.msc = &fake_msc1;				\
+	INIT_LIST_HEAD(&fake_vmsc2.ris);			\
+	INIT_LIST_HEAD(&fake_vmsc2.comp_list);			\
+	fake_vmsc2.msc = &fake_msc2;				\
+								\
+	memset(&fake_ris1, 0, sizeof(fake_ris1));		\
+	memset(&fake_ris2, 0, sizeof(fake_ris2));		\
+	fake_ris1.ris_idx = 1;					\
+	INIT_LIST_HEAD(&fake_ris1.msc_list);			\
+	fake_ris2.ris_idx = 2;					\
+	INIT_LIST_HEAD(&fake_ris2.msc_list);			\
+								\
+	fake_msc1.pdev = &fake_pdev;				\
+	fake_msc2.pdev = &fake_pdev;				\
+								\
+	list_add(&fake_class.classes_list, &fake_classes_list);	\
+} while (0)
+
+	RESET_FAKE_HIEARCHY();
+
+	mutex_lock(&mpam_list_lock);
+
+	/* One Class+Comp, two RIS in one vMSC with common features */
+	fake_comp1.class = &fake_class;
+	list_add(&fake_comp1.class_list, &fake_class.components);
+	fake_comp2.class = NULL;
+	fake_vmsc1.comp = &fake_comp1;
+	list_add(&fake_vmsc1.comp_list, &fake_comp1.vmsc);
+	fake_vmsc2.comp = NULL;
+	fake_ris1.vmsc = &fake_vmsc1;
+	list_add(&fake_ris1.vmsc_list, &fake_vmsc1.ris);
+	fake_ris2.vmsc = &fake_vmsc1;
+	list_add(&fake_ris2.vmsc_list, &fake_vmsc1.ris);
+
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris1.props);
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris2.props);
+	fake_ris1.props.cpbm_wd = 4;
+	fake_ris2.props.cpbm_wd = 4;
+
+	mpam_enable_merge_features(&fake_classes_list);
+
+	KUNIT_EXPECT_TRUE(test, mpam_has_feature(mpam_feat_cpor_part, &fake_class.props));
+	KUNIT_EXPECT_EQ(test, fake_class.props.cpbm_wd, 4);
+
+	RESET_FAKE_HIEARCHY();
+
+	/* One Class+Comp, two RIS in one vMSC with non-overlapping features */
+	fake_comp1.class = &fake_class;
+	list_add(&fake_comp1.class_list, &fake_class.components);
+	fake_comp2.class = NULL;
+	fake_vmsc1.comp = &fake_comp1;
+	list_add(&fake_vmsc1.comp_list, &fake_comp1.vmsc);
+	fake_vmsc2.comp = NULL;
+	fake_ris1.vmsc = &fake_vmsc1;
+	list_add(&fake_ris1.vmsc_list, &fake_vmsc1.ris);
+	fake_ris2.vmsc = &fake_vmsc1;
+	list_add(&fake_ris2.vmsc_list, &fake_vmsc1.ris);
+
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris1.props);
+	mpam_set_feature(mpam_feat_cmax_cmin, &fake_ris2.props);
+	fake_ris1.props.cpbm_wd = 4;
+	fake_ris2.props.cmax_wd = 4;
+
+	mpam_enable_merge_features(&fake_classes_list);
+
+	/* Multiple RIS within one MSC controlling the same resource can be mismatched */
+	KUNIT_EXPECT_TRUE(test, mpam_has_feature(mpam_feat_cpor_part, &fake_class.props));
+	KUNIT_EXPECT_TRUE(test, mpam_has_feature(mpam_feat_cmax_cmin, &fake_class.props));
+	KUNIT_EXPECT_TRUE(test, mpam_has_feature(mpam_feat_cmax_cmin, &fake_vmsc1.props));
+	KUNIT_EXPECT_EQ(test, fake_class.props.cpbm_wd, 4);
+	KUNIT_EXPECT_EQ(test, fake_vmsc1.props.cmax_wd, 4);
+	KUNIT_EXPECT_EQ(test, fake_class.props.cmax_wd, 4);
+
+	RESET_FAKE_HIEARCHY();
+
+	/* One Class+Comp, two MSC with overlapping features */
+	fake_comp1.class = &fake_class;
+	list_add(&fake_comp1.class_list, &fake_class.components);
+	fake_comp2.class = NULL;
+	fake_vmsc1.comp = &fake_comp1;
+	list_add(&fake_vmsc1.comp_list, &fake_comp1.vmsc);
+	fake_vmsc2.comp = &fake_comp1;
+	list_add(&fake_vmsc2.comp_list, &fake_comp1.vmsc);
+	fake_ris1.vmsc = &fake_vmsc1;
+	list_add(&fake_ris1.vmsc_list, &fake_vmsc1.ris);
+	fake_ris2.vmsc = &fake_vmsc2;
+	list_add(&fake_ris2.vmsc_list, &fake_vmsc2.ris);
+
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris1.props);
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris2.props);
+	fake_ris1.props.cpbm_wd = 4;
+	fake_ris2.props.cpbm_wd = 4;
+
+	mpam_enable_merge_features(&fake_classes_list);
+
+	KUNIT_EXPECT_TRUE(test, mpam_has_feature(mpam_feat_cpor_part, &fake_class.props));
+	KUNIT_EXPECT_EQ(test, fake_class.props.cpbm_wd, 4);
+
+	RESET_FAKE_HIEARCHY();
+
+	/* One Class+Comp, two MSC with non-overlapping features */
+	fake_comp1.class = &fake_class;
+	list_add(&fake_comp1.class_list, &fake_class.components);
+	fake_comp2.class = NULL;
+	fake_vmsc1.comp = &fake_comp1;
+	list_add(&fake_vmsc1.comp_list, &fake_comp1.vmsc);
+	fake_vmsc2.comp = &fake_comp1;
+	list_add(&fake_vmsc2.comp_list, &fake_comp1.vmsc);
+	fake_ris1.vmsc = &fake_vmsc1;
+	list_add(&fake_ris1.vmsc_list, &fake_vmsc1.ris);
+	fake_ris2.vmsc = &fake_vmsc2;
+	list_add(&fake_ris2.vmsc_list, &fake_vmsc2.ris);
+
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris1.props);
+	mpam_set_feature(mpam_feat_cmax_cmin, &fake_ris2.props);
+	fake_ris1.props.cpbm_wd = 4;
+	fake_ris2.props.cmax_wd = 4;
+
+	mpam_enable_merge_features(&fake_classes_list);
+
+	/*
+	 * Multiple RIS in different MSC can't the same resource, mismatched
+	 * features can not be supported.
+	 */
+	KUNIT_EXPECT_FALSE(test, mpam_has_feature(mpam_feat_cpor_part, &fake_class.props));
+	KUNIT_EXPECT_FALSE(test, mpam_has_feature(mpam_feat_cmax_cmin, &fake_class.props));
+	KUNIT_EXPECT_EQ(test, fake_class.props.cpbm_wd, 0);
+	KUNIT_EXPECT_EQ(test, fake_class.props.cmax_wd, 0);
+
+	RESET_FAKE_HIEARCHY();
+
+	/* One Class+Comp, two MSC with incompatible overlapping features */
+	fake_comp1.class = &fake_class;
+	list_add(&fake_comp1.class_list, &fake_class.components);
+	fake_comp2.class = NULL;
+	fake_vmsc1.comp = &fake_comp1;
+	list_add(&fake_vmsc1.comp_list, &fake_comp1.vmsc);
+	fake_vmsc2.comp = &fake_comp1;
+	list_add(&fake_vmsc2.comp_list, &fake_comp1.vmsc);
+	fake_ris1.vmsc = &fake_vmsc1;
+	list_add(&fake_ris1.vmsc_list, &fake_vmsc1.ris);
+	fake_ris2.vmsc = &fake_vmsc2;
+	list_add(&fake_ris2.vmsc_list, &fake_vmsc2.ris);
+
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris1.props);
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris2.props);
+	mpam_set_feature(mpam_feat_mbw_part, &fake_ris1.props);
+	mpam_set_feature(mpam_feat_mbw_part, &fake_ris2.props);
+	fake_ris1.props.cpbm_wd = 5;
+	fake_ris2.props.cpbm_wd = 3;
+	fake_ris1.props.mbw_pbm_bits = 5;
+	fake_ris2.props.mbw_pbm_bits = 3;
+
+	mpam_enable_merge_features(&fake_classes_list);
+
+	/*
+	 * Multiple RIS in different MSC can't the same resource, mismatched
+	 * features can not be supported.
+	 */
+	KUNIT_EXPECT_FALSE(test, mpam_has_feature(mpam_feat_cpor_part, &fake_class.props));
+	KUNIT_EXPECT_FALSE(test, mpam_has_feature(mpam_feat_mbw_part, &fake_class.props));
+	KUNIT_EXPECT_EQ(test, fake_class.props.cpbm_wd, 0);
+	KUNIT_EXPECT_EQ(test, fake_class.props.mbw_pbm_bits, 0);
+
+	RESET_FAKE_HIEARCHY();
+
+	/* One Class+Comp, two MSC with overlapping features that need tweaking */
+	fake_comp1.class = &fake_class;
+	list_add(&fake_comp1.class_list, &fake_class.components);
+	fake_comp2.class = NULL;
+	fake_vmsc1.comp = &fake_comp1;
+	list_add(&fake_vmsc1.comp_list, &fake_comp1.vmsc);
+	fake_vmsc2.comp = &fake_comp1;
+	list_add(&fake_vmsc2.comp_list, &fake_comp1.vmsc);
+	fake_ris1.vmsc = &fake_vmsc1;
+	list_add(&fake_ris1.vmsc_list, &fake_vmsc1.ris);
+	fake_ris2.vmsc = &fake_vmsc2;
+	list_add(&fake_ris2.vmsc_list, &fake_vmsc2.ris);
+
+	mpam_set_feature(mpam_feat_mbw_min, &fake_ris1.props);
+	mpam_set_feature(mpam_feat_mbw_min, &fake_ris2.props);
+	mpam_set_feature(mpam_feat_cmax_cmax, &fake_ris1.props);
+	mpam_set_feature(mpam_feat_cmax_cmax, &fake_ris2.props);
+	fake_ris1.props.bwa_wd = 5;
+	fake_ris2.props.bwa_wd = 3;
+	fake_ris1.props.cmax_wd = 5;
+	fake_ris2.props.cmax_wd = 3;
+
+	mpam_enable_merge_features(&fake_classes_list);
+
+	/*
+	 * Multiple RIS in different MSC can't the same resource, mismatched
+	 * features can not be supported.
+	 */
+	KUNIT_EXPECT_TRUE(test, mpam_has_feature(mpam_feat_mbw_min, &fake_class.props));
+	KUNIT_EXPECT_TRUE(test, mpam_has_feature(mpam_feat_cmax_cmax, &fake_class.props));
+	KUNIT_EXPECT_EQ(test, fake_class.props.bwa_wd, 3);
+	KUNIT_EXPECT_EQ(test, fake_class.props.cmax_wd, 3);
+
+	RESET_FAKE_HIEARCHY();
+
+	/* One Class Two Comp with overlapping features */
+	fake_comp1.class = &fake_class;
+	list_add(&fake_comp1.class_list, &fake_class.components);
+	fake_comp2.class = &fake_class;
+	list_add(&fake_comp2.class_list, &fake_class.components);
+	fake_vmsc1.comp = &fake_comp1;
+	list_add(&fake_vmsc1.comp_list, &fake_comp1.vmsc);
+	fake_vmsc2.comp = &fake_comp2;
+	list_add(&fake_vmsc2.comp_list, &fake_comp2.vmsc);
+	fake_ris1.vmsc = &fake_vmsc1;
+	list_add(&fake_ris1.vmsc_list, &fake_vmsc1.ris);
+	fake_ris2.vmsc = &fake_vmsc2;
+	list_add(&fake_ris2.vmsc_list, &fake_vmsc2.ris);
+
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris1.props);
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris2.props);
+	fake_ris1.props.cpbm_wd = 4;
+	fake_ris2.props.cpbm_wd = 4;
+
+	mpam_enable_merge_features(&fake_classes_list);
+
+	KUNIT_EXPECT_TRUE(test, mpam_has_feature(mpam_feat_cpor_part, &fake_class.props));
+	KUNIT_EXPECT_EQ(test, fake_class.props.cpbm_wd, 4);
+
+	RESET_FAKE_HIEARCHY();
+
+	/* One Class Two Comp with non-overlapping features */
+	fake_comp1.class = &fake_class;
+	list_add(&fake_comp1.class_list, &fake_class.components);
+	fake_comp2.class = &fake_class;
+	list_add(&fake_comp2.class_list, &fake_class.components);
+	fake_vmsc1.comp = &fake_comp1;
+	list_add(&fake_vmsc1.comp_list, &fake_comp1.vmsc);
+	fake_vmsc2.comp = &fake_comp2;
+	list_add(&fake_vmsc2.comp_list, &fake_comp2.vmsc);
+	fake_ris1.vmsc = &fake_vmsc1;
+	list_add(&fake_ris1.vmsc_list, &fake_vmsc1.ris);
+	fake_ris2.vmsc = &fake_vmsc2;
+	list_add(&fake_ris2.vmsc_list, &fake_vmsc2.ris);
+
+	mpam_set_feature(mpam_feat_cpor_part, &fake_ris1.props);
+	mpam_set_feature(mpam_feat_cmax_cmin, &fake_ris2.props);
+	fake_ris1.props.cpbm_wd = 4;
+	fake_ris2.props.cmax_wd = 4;
+
+	mpam_enable_merge_features(&fake_classes_list);
+
+	/*
+	 * Multiple components can't control the same resource, mismatched features can
+	 * not be supported.
+	 */
+	KUNIT_EXPECT_FALSE(test, mpam_has_feature(mpam_feat_cpor_part, &fake_class.props));
+	KUNIT_EXPECT_FALSE(test, mpam_has_feature(mpam_feat_cmax_cmin, &fake_class.props));
+	KUNIT_EXPECT_EQ(test, fake_class.props.cpbm_wd, 0);
+	KUNIT_EXPECT_EQ(test, fake_class.props.cmax_wd, 0);
+
+	mutex_unlock(&mpam_list_lock);
+
+#undef RESET_FAKE_HIEARCHY
+}
+
In file included from drivers/resctrl/mpam_devices.c:2908:
drivers/resctrl/test_mpam_devices.c: In function 
‘test_mpam_enable_merge_features’:
drivers/resctrl/test_mpam_devices.c:325:1: error: the frame size of 5520 
bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
  325 | }
      | ^

It's better to split the big function into a few sub-tests. Each 
sub-test defines and uses less variables to avoid big frame size issue.

[SNIP]

Thanks.

-Fenghua








