[PATCH 12/33] arm_mpam: Add the class and component structures for ris firmware described

[James Morse]

Hi Fenghua,

On 28/08/2025 02:29, Fenghua Yu wrote:
> On 8/22/25 08:29, James Morse wrote:
>> An MSC is a container of resources, each identified by their RIS index.
>> Some RIS are described by firmware to provide their position in the system.
>> Others are discovered when the driver probes the hardware.
>>
>> To configure a resource it needs to be found by its class, e.g. 'L2'.
>> There are two kinds of grouping, a class is a set of components, which
>> are visible to user-space as there are likely to be multiple instances
>> of the L2 cache. (e.g. one per cluster or package)
>>
>> struct mpam_components are a set of struct mpam_vmsc. A vMSC groups the
>> RIS in an MSC that control the same logical piece of hardware. (e.g. L2).
>> This is to allow hardware implementations where two controls are presented
>> as different RIS. Re-combining these RIS allows their feature bits to
>> be or-ed. This structure is not visible outside mpam_devices.c
>>
>> struct mpam_vmsc are then a set of struct mpam_msc_ris, which are not
>> visible as each L2 cache may be composed of individual slices which need
>> to be configured the same as the hardware is not able to distribute the
>> configuration.
>>
>> Add support for creating and destroying these structures.
>>
>> A gfp is passed as the structures may need creating when a new RIS entry
>> is discovered when probing the MSC.

>> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
>> index 71a1fb1a9c75..5baf2a8786fb 100644
>> --- a/drivers/resctrl/mpam_devices.c
>> +++ b/drivers/resctrl/mpam_devices.c
> [SNIP]
>> +static struct mpam_vmsc *
>> +mpam_vmsc_alloc(struct mpam_component *comp, struct mpam_msc *msc, gfp_t gfp)
>> +{
>> +    struct mpam_vmsc *vmsc;
>> +
>> +    lockdep_assert_held(&mpam_list_lock);
>> +
>> +    vmsc = kzalloc(sizeof(*vmsc), gfp);
>> +    if (!comp)
> 
> s/if (!cmp)/if (!vmsc)/
> 
> 
>> +        return ERR_PTR(-ENOMEM);

Yup, that's a copy-and-paste typo. Fixed,


Thanks,

James