linux-kernel - Re: [PATCH v2 19/29] arm_mpam: Use a static key to indicate when mpam is enabled

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Message-ID: <7b72615a-a1a5-4945-9199-d30b7caee70b@arm.com>
Date: Fri, 12 Sep 2025 15:42:59 +0100
From: Ben Horgan <ben.horgan@....com>
To: James Morse <james.morse@....com>, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-acpi@...r.kernel.org
Cc: D Scott Phillips OS <scott@...amperecomputing.com>,
 carl@...amperecomputing.com, lcherian@...vell.com,
 bobo.shaobowang@...wei.com, tan.shaopeng@...itsu.com,
 baolin.wang@...ux.alibaba.com, Jamie Iles <quic_jiles@...cinc.com>,
 Xin Hao <xhao@...ux.alibaba.com>, peternewman@...gle.com,
 dfustini@...libre.com, amitsinght@...vell.com,
 David Hildenbrand <david@...hat.com>, Dave Martin <dave.martin@....com>,
 Koba Ko <kobak@...dia.com>, Shanker Donthineni <sdonthineni@...dia.com>,
 fenghuay@...dia.com, baisheng.gao@...soc.com,
 Jonathan Cameron <jonathan.cameron@...wei.com>, Rob Herring
 <robh@...nel.org>, Rohit Mathew <rohit.mathew@....com>,
 Rafael Wysocki <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
 Lorenzo Pieralisi <lpieralisi@...nel.org>, Hanjun Guo
 <guohanjun@...wei.com>, Sudeep Holla <sudeep.holla@....com>,
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Danilo Krummrich <dakr@...nel.org>
Subject: Re: [PATCH v2 19/29] arm_mpam: Use a static key to indicate when mpam
 is enabled

Hi James,

On 9/10/25 21:42, James Morse wrote:
> Once all the MSC have been probed, the system wide usable number of
> PARTID is known and the configuration arrays can be allocated.
> 
> After this point, checking all the MSC have been probed is pointless,
> and the cpuhp callbacks should restore the configuration, instead of
> just resetting the MSC.
> 
> Add a static key to enable this behaviour. This will also allow MPAM
> to be disabled in repsonse to an error, and the architecture code to
> enable/disable the context switch of the MPAM system registers.
> 
> Signed-off-by: James Morse <james.morse@....com>
> ---
>  drivers/resctrl/mpam_devices.c  | 12 ++++++++++++
>  drivers/resctrl/mpam_internal.h |  8 ++++++++
>  2 files changed, 20 insertions(+)
> 

Reviewed-by: Ben Horgan <ben.horgan@....com>

Thanks,

Ben