Re: [RFC PATCH 09/19] x86/resctrl: Add plza_capable in rdt_resource data structure

["Moger, Babu" <bmoger@amd.com>]

Hi Ben,


On 2/11/2026 9:19 AM, Ben Horgan wrote:
> Hi Babu,
> 
> On 1/21/26 21:12, Babu Moger wrote:
>> Add plza_capable field to the rdt_resource structure to indicate whether
>> Privilege Level Zero Association (PLZA) is supported for that resource
>> type.
>>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>>   arch/x86/kernel/cpu/resctrl/core.c     | 6 ++++++
>>   arch/x86/kernel/cpu/resctrl/rdtgroup.c | 5 +++++
>>   include/linux/resctrl.h                | 3 +++
>>   3 files changed, 14 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
>> index 2de3140dd6d1..e41fe5fa3f30 100644
>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>> @@ -295,6 +295,9 @@ static __init bool __rdt_get_mem_config_amd(struct rdt_resource *r)
>>   
>>   	r->alloc_capable = true;
>>   
>> +	if (rdt_cpu_has(X86_FEATURE_PLZA))
>> +		r->plza_capable = true;
>> +
>>   	return true;
>>   }
>>   
>> @@ -314,6 +317,9 @@ static void rdt_get_cache_alloc_cfg(int idx, struct rdt_resource *r)
>>   	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
>>   		r->cache.arch_has_sparse_bitmasks = ecx.split.noncont;
>>   	r->alloc_capable = true;
>> +
>> +	if (rdt_cpu_has(X86_FEATURE_PLZA))
>> +		r->plza_capable = true;
>>   }
>>   
>>   static void rdt_get_cdp_config(int level)
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 885026468440..540e1e719d7f 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -229,6 +229,11 @@ bool resctrl_arch_get_cdp_enabled(enum resctrl_res_level l)
>>   	return rdt_resources_all[l].cdp_enabled;
>>   }
>>   
>> +bool resctrl_arch_get_plza_capable(enum resctrl_res_level l)
>> +{
>> +	return rdt_resources_all[l].r_resctrl.plza_capable;
>> +}
>> +
>>   void resctrl_arch_reset_all_ctrls(struct rdt_resource *r)
>>   {
>>   	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
>> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
>> index 63d74c0dbb8f..ae252a0e6d92 100644
>> --- a/include/linux/resctrl.h
>> +++ b/include/linux/resctrl.h
>> @@ -319,6 +319,7 @@ struct resctrl_mon {
>>    * @name:		Name to use in "schemata" file.
>>    * @schema_fmt:		Which format string and parser is used for this schema.
>>    * @cdp_capable:	Is the CDP feature available on this resource
>> + * @plza_capable:	Is Privilege Level Zero Association capable?
>>    */
>>   struct rdt_resource {
>>   	int			rid;
>> @@ -334,6 +335,7 @@ struct rdt_resource {
>>   	char			*name;
>>   	enum resctrl_schema_fmt	schema_fmt;
>>   	bool			cdp_capable;
>> +	bool			plza_capable;
> 
> Why are you making plza a resource property? Certainly for MPAM we'd
> want this to be global across resources and I see above that you are
> just checking a cpu property rather then anything per resource.

Yes. I agree. This does not have to be resource property.

Will make it as global property where it can be set from arch.

Thanks

Babu