Re: [PATCH v6 02/40] arm_mpam: Reset when feature configuration bit unset

[Gavin Shan]

On 3/14/26 12:45 AM, Ben Horgan wrote:
> To indicate that the configuration, of the controls used by resctrl, in a
> RIS need resetting to driver defaults the reset flags in mpam_config are
> set. However, these flags are only ever set temporarily at RIS scope in
> mpam_reset_ris() and hence mpam_cpu_online() will never reset these
> controls to default. As the hardware reset is unknown this leads to unknown
> configuration when the control values haven't been configured away from the
> defaults.
>
> Use the policy that an unset feature configuration bit means reset. In this
> way the mpam_config in the component can encode that it should be in reset
> state and mpam_reprogram_msc() will reset controls as needed.
>
> Fixes: 09b89d2a72f3 ("arm_mpam: Allow configuration to be applied and restored during cpu online")
> Signed-off-by: Ben Horgan <ben.horgan@xxxxxxx>
> ---
> This goes back to the initial feature configuration policy that James
> used in the MPAM base driver rfc but I unfortunately
> suggested him to change it.
> ---
>   drivers/resctrl/mpam_devices.c | 40 ++++++++++------------------------
>   1 file changed, 12 insertions(+), 28 deletions(-)

Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>