Re: [PATCH v2 29/29] arm_mpam: Add kunit tests for props_mismatch()

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Wed, 10 Sep 2025 20:43:09 +0000
James Morse <james.morse@arm.com> 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>
Nice in general though I didn't go through the test expected results etc.
A few comments inline.

Thanks and looking forward to seeing this go in.

Jonathan

> ---
> Changes since v1:
>  * Waggled some words in comments.
>  * Moved a bunch of variables to be global - shuts up a compiler warning.
> ---
>  drivers/resctrl/mpam_internal.h     |   8 +-
>  drivers/resctrl/test_mpam_devices.c | 321 ++++++++++++++++++++++++++++
>  2 files changed, 328 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
> index 7cbcafe8294a..6119e4573187 100644
> --- a/drivers/resctrl/mpam_internal.h
> +++ b/drivers/resctrl/mpam_internal.h
> @@ -20,6 +20,12 @@
>  
>  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);
> @@ -189,7 +195,7 @@ struct mpam_props {
>  	u16			dspri_wd;
>  	u16			num_csu_mon;
>  	u16			num_mbwu_mon;
> -};
> +} PACKED_FOR_KUNIT;

Add a comment on 'why'.

>  
>  #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 3e7058f7601c..4eca8590c691 100644
> --- a/drivers/resctrl/test_mpam_devices.c
> +++ b/drivers/resctrl/test_mpam_devices.c
> @@ -4,6 +4,325 @@
>  
>  #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 struct list_head fake_classes_list;
> +static struct mpam_class fake_class = { 0 };
> +static struct mpam_component fake_comp1 = { 0 };
> +static struct mpam_component fake_comp2 = { 0 };
> +static struct mpam_vmsc fake_vmsc1 = { 0 };
> +static struct mpam_vmsc fake_vmsc2 = { 0 };
> +static struct mpam_msc fake_msc1 = { 0 };
> +static struct mpam_msc fake_msc2 = { 0 };
> +static struct mpam_msc_ris fake_ris1 = { 0 };
> +static struct mpam_msc_ris fake_ris2 = { 0 };
> +static struct platform_device fake_pdev = { 0 };
> +
> +static void test_mpam_enable_merge_features(struct kunit *test)
> +{
> +#define RESET_FAKE_HIEARCHY()	do {				\
> +	INIT_LIST_HEAD(&fake_classes_list);			\
> +								\
> +	memset(&fake_class, 0, sizeof(fake_class));		\

Maybe just use a function?  Seems to be changing stuff that is
global mostly anyway so seems like it won't need large numbers
of parameters or anything like that.

> +	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();