Re: [PATCH v3 09/47] arm64: mpam: Add cpu_pm notifier to restore MPAM sysregs

Gavin Shan
2026-01-19T06:41:15Z

On 1/13/26 12:58 AM, Ben Horgan wrote:
> From: James Morse <james.morse@arm.com>
>
> The MPAM system registers will be lost if the CPU is reset during PSCI's
> CPU_SUSPEND.
>
> Add a PM notifier to restore them.
>
> mpam_thread_switch(current) can't be used as this won't make any changes if
> the in-memory copy says the register already has the correct value. In
> reality the system register is UNKNOWN out of reset.
>
> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> Signed-off-by: James Morse <james.morse@arm.com>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
> ---
> arch/arm64/kernel/mpam.c | 30 ++++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>

Reviewed-by: Gavin Shan <gshan@redhat.com>