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

[Ben Horgan <ben.horgan@arm.com>]

Hi James,

The tests seem reasonable. Just some comments on the comments.

On 8/22/25 16:30, 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@arm.com>
> ---
>  drivers/resctrl/mpam_internal.h     |   8 +-
>  drivers/resctrl/test_mpam_devices.c | 322 ++++++++++++++++++++++++++++
>  2 files changed, 329 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
> index bbf0306abc82..6e973be095f8 100644
> --- a/drivers/resctrl/mpam_internal.h
> +++ b/drivers/resctrl/mpam_internal.h
> @@ -18,6 +18,12 @@
>  
>  DECLARE_STATIC_KEY_FALSE(mpam_enabled);
>  
> +#ifdef CONFIG_MPAM_KUNIT_TEST
> +#define PACKED_FOR_KUNIT __packed
> +#else
> +#define PACKED_FOR_KUNIT
> +#endif
> +
>  static inline bool mpam_is_enabled(void)
>  {
>  	return static_branch_likely(&mpam_enabled);
> @@ -209,7 +215,7 @@ struct mpam_props {
>  	u16			dspri_wd;
>  	u16			num_csu_mon;
>  	u16			num_mbwu_mon;
> -};
> +} PACKED_FOR_KUNIT;
>  
>  #define mpam_has_feature(_feat, x)	((1 << (_feat)) & (x)->features)
>  
> 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
s/can't the same/can't control the same/

> +	 * 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.
> +	 */
Missing the word "control" again.

> +	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.
> +	 */
Comment is for a different case.
> +	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
> +}
> +
>  static void test_mpam_reset_msc_bitmap(struct kunit *test)
>  {
>  	char *buf = kunit_kzalloc(test, SZ_16K, GFP_KERNEL);
> @@ -57,6 +377,8 @@ static void test_mpam_reset_msc_bitmap(struct kunit *test)
>  
>  static struct kunit_case mpam_devices_test_cases[] = {
>  	KUNIT_CASE(test_mpam_reset_msc_bitmap),
> +	KUNIT_CASE(test_mpam_enable_merge_features),
> +	KUNIT_CASE(test__props_mismatch),
>  	{}
>  };
>  

Thanks,

Ben