Re: [PATCH 2/7] x86/resctrl: Add SDCIAE feature in the command line options

[Reinette Chatre <reinette.chatre@xxxxxxxxx>]

Hi Babu,

On 8/16/24 9:16 AM, Babu Moger wrote:
> Add the command line options to enable or disable the new resctrl feature
> L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE).
>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
>   Documentation/admin-guide/kernel-parameters.txt | 2 +-
>   arch/x86/kernel/cpu/resctrl/core.c              | 2 ++
>   2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 09126bb8cc9f..63f17d23b8f4 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -5604,7 +5604,7 @@
>   	rdt=		[HW,X86,RDT]
>   			Turn on/off individual RDT features. List is:
>   			cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, l2cdp,
> -			mba, smba, bmec.
> +			mba, smba, bmec, sdciae.
>   			E.g. to turn on cmt and turn off mba use:
>   				rdt=cmt,!mba
>   
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 1930fce9dfe9..c4dfc768ddf5 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -801,6 +801,7 @@ enum {
>   	RDT_FLAG_MBA,
>   	RDT_FLAG_SMBA,
>   	RDT_FLAG_BMEC,
> +	RDT_FLAG_SDCIAE,
>   };
>   
>   #define RDT_OPT(idx, n, f)	\
> @@ -826,6 +827,7 @@ static struct rdt_options rdt_options[]  __initdata = {
>   	RDT_OPT(RDT_FLAG_MBA,	    "mba",	X86_FEATURE_MBA),
>   	RDT_OPT(RDT_FLAG_SMBA,	    "smba",	X86_FEATURE_SMBA),
>   	RDT_OPT(RDT_FLAG_BMEC,	    "bmec",	X86_FEATURE_BMEC),
> +	RDT_OPT(RDT_FLAG_SDCIAE,    "sdciae",	X86_FEATURE_SDCIAE),
>   };
>   #define NUM_RDT_OPTIONS ARRAY_SIZE(rdt_options)
>   

Why is this needed when patch #5 introduces an interface to enable/disable
this feature after mount?

Reinette