Re: [PATCH v4 08/41] arm64: mpam: Add cpu_pm notifier to restore MPAM sysregs

Catalin Marinas
2026-02-05T16:54:31Z

On Tue, Feb 03, 2026 at 09:43:09PM +0000, 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.
>
> 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: James Morse <james.morse@arm.com>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>

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