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

[Ben Horgan]

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@xxxxxxx>
> ---
>  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.

>  };
>  
>  /*
> @@ -481,6 +483,7 @@ static inline u32 resctrl_get_config_index(u32 closid,
>  
>  bool resctrl_arch_get_cdp_enabled(enum resctrl_res_level l);
>  int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable);
> +bool resctrl_arch_get_plza_capable(enum resctrl_res_level l);
>  
>  /**
>   * resctrl_arch_mbm_cntr_assign_enabled() - Check if MBM counter assignment


Thanks,

Ben