Re: [PATCH v5 03/16] x86/resctrl: Add PLZA configuration definitions and data structures

[Reinette Chatre <reinette.chatre@intel.com>]

Hi Babu,

On 8/26/26 12:32 PM, Babu Moger wrote:
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index e3cfa0c10e92..2f4c60487a5d 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -222,6 +222,53 @@ union l3_qos_abmc_cfg {
>  	unsigned long full;
>  };
>  
> +/*

I understand that this is not specifically kernel-doc (since no /**)
but it clearly follows the pattern and also needs to match the 
style used in this file. Considering this, please use custom that
describes members first before the long description? With members
described first the long description can then use @ when referring to
the members.

> + * Privilege Level Zero Association (PLZA) is configured via
> + * MSR_IA32_PQR_PLZA_ASSOC. This MSR must be programmed on every CPU in
> + * a QoS domain. Each domain supports a single PLZA CLOSID and/or RMID
> + * association, and all fields except PLZA_EN must be programmed
> + * identically across the domain to ensure consistent behavior.
> + *
> + * RMID and CLOSID selection are controlled independently. When PLZA is
> + * enabled (plza_en = 1), CPL0 uses CLOSID and RMID values from
> + * MSR_IA32_PQR_PLZA_ASSOC depending on the corresponding enable bits.
> + * When PLZA is disabled (plza_en = 0), the CLOSID and RMID are always
> + * taken from MSR_IA32_PQR_ASSOC regardless of privilege level.
> + *
> + *   - rmid_en = 1: use the RMID programmed in this MSR.

"this MSR" -> "MSR_IA32_PQR_PLZA_ASSOC" or keeping text similar to the
rmid_en = 0 scenario may make it easier to follow what the bit accomplishes: 
	- @rmid_en = 1: use the RMID from MSR_IA32_PQR_PLZA_ASSOC if
			@plza_en = 1

> + *   - rmid_en = 0: use the RMID from MSR_IA32_PQR_ASSOC.
> + *   - closid_en = 1: use the CLOSID programmed in this MSR.

same comment as for rmid_en bit:
	- @closid_en = 1: use the CLOSID from MSR_IA32_PQR_PLZA_ASSOC
			  if @plza_en = 1

> + *   - closid_en = 0: use the CLOSID from MSR_IA32_PQR_ASSOC.
> + *
> + * This allows PLZA to override only RMID, only CLOSID, or both. If both
> + * rmid_en and closid_en are clear, the effective behavior is the same as
> + * when PLZA is disabled, with RMID and CLOSID derived from

"derived from" -> "used from"?

> + * MSR_IA32_PQR_ASSOC irrespective of privilege level.
> + *
> + * @rmid		: RMID programmed for PLZA.
> + * @reserved1		: Reserved.
> + * @rmid_en		: Enable RMID for PLZA.
> + * @closid		: CLOSID programmed for PLZA.
> + * @reserved2		: Reserved.
> + * @closid_en		: Enable CLOSID for PLZA.
> + * @reserved3		: Reserved.
> + * @plza_en		: Enable PLZA. When enabled, PLZA applies to the
> + *			  given CPU.
> + */
> +union msr_pqr_plza_assoc {
> +	struct {
> +		u64	rmid		:12,
> +			reserved1	:19,
> +			rmid_en		: 1,
> +			closid		: 4,
> +			reserved2	:11,
> +			closid_en	: 1,
> +			reserved3	:15,
> +			plza_en		: 1;
> +	} split;
> +	u64	full;
> +};
> +
>  void rdt_ctrl_update(void *arg);
>  
>  int rdt_get_l3_mon_config(struct rdt_resource *r);

Reinette