Re: [PATCH v4 09/41] arm64: mpam: Initialise and context switch the MPAMSM_EL1 register

Catalin Marinas
2026-02-05T16:55:22Z

On Tue, Feb 03, 2026 at 09:43:10PM +0000, Ben Horgan wrote:
> The MPAMSM_EL1 sets the MPAM labels, PMG and PARTID, for loads and stores
> generated by a shared SMCU. Disable the traps so the kernel can use it and
> set it to the same configuration as the per-EL cpu MPAM configuration.
>
> If an SMCU is not shared with other cpus then it is implementation
> defined whether the configuration from MPAMSM_EL1 is used or that from
> the appropriate MPAMy_ELx. As we set the same, PMG_D and PARTID_D,
> configuration for MPAM0_EL1, MPAM1_EL1 and MPAMSM_EL1 the resulting
> configuration is the same regardless.
>
> The range of valid configurations for the PARTID and PMG in MPAMSM_EL1 is
> not currently specified in Arm Architectural Reference Manual but the
> architect has confirmed that it is intended to be the same as that for the
> cpu configuration in the MPAMy_ELx registers.
>
> Tested-by: Gavin Shan <gshan@redhat.com>
> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
> Tested-by: Peter Newman <peternewman@google.com>
> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>