linux-kernel - Re: [PATCH 33/33] arm_mpam: Add kunit tests for props

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Message-ID: <4d7a9b82-9d96-4796-949d-d32c02b6af28@arm.com>
Date: Wed, 10 Sep 2025 20:31:02 +0100
From: James Morse <james.morse@....com>
To: Ben Horgan <ben.horgan@....com>, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-acpi@...r.kernel.org,
 devicetree@...r.kernel.org
Cc: shameerali.kolothum.thodi@...wei.com,
 D Scott Phillips OS <scott@...amperecomputing.com>,
 carl@...amperecomputing.com, lcherian@...vell.com,
 bobo.shaobowang@...wei.com, tan.shaopeng@...itsu.com,
 baolin.wang@...ux.alibaba.com, Jamie Iles <quic_jiles@...cinc.com>,
 Xin Hao <xhao@...ux.alibaba.com>, peternewman@...gle.com,
 dfustini@...libre.com, amitsinght@...vell.com,
 David Hildenbrand <david@...hat.com>, Rex Nie <rex.nie@...uarmicro.com>,
 Dave Martin <dave.martin@....com>, Koba Ko <kobak@...dia.com>,
 Shanker Donthineni <sdonthineni@...dia.com>, fenghuay@...dia.com,
 baisheng.gao@...soc.com, Jonathan Cameron <jonathan.cameron@...wei.com>,
 Rob Herring <robh@...nel.org>, Rohit Mathew <rohit.mathew@....com>,
 Rafael Wysocki <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
 Lorenzo Pieralisi <lpieralisi@...nel.org>, Hanjun Guo
 <guohanjun@...wei.com>, Sudeep Holla <sudeep.holla@....com>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Catalin Marinas <catalin.marinas@....com>,
 Will Deacon <will@...nel.org>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Danilo Krummrich <dakr@...nel.org>
Subject: Re: [PATCH 33/33] arm_mpam: Add kunit tests for props_mismatch()

Hi Ben,

On 29/08/2025 18:11, Ben Horgan wrote:
> 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.

>> 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 @@
>> +static void test_mpam_enable_merge_features(struct kunit *test)
>> +{

[...]

>> +	/* 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/

Thanks,


>> +	 * 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.

Copy and paste!


>> +	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.

Fixed as:
	/*
	 * RIS with different control properties need to be sanitised so the
	 * class has the common set of properties.
	 */


>> +	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);


Thanks,

James