Re: [PATCH v6 10/10] arm_mpam: detect and enable MPAM-Fb PCC support

Hi Ben,

On 7/31/26 10:22, Ben Horgan wrote:
> Hi Andre,
> 
> On 7/31/26 09:16, Andre Przywara wrote:
>> Hi Ben,
>>
>> On 7/30/26 18:13, Ben Horgan wrote:
>>> Hi Andre,
>>>
>>> On 7/30/26 16:25, Andre Przywara wrote:
>>>> The Arm MPAM-Fb specification [1] describes a protocol to access MSC
>>>> registers through a firmware interface. This requires a shared memory
>>>> region to hold the message, and a mailbox to trigger the access.
>>>> For ACPI this is wrapped as a PCC channel, described using existing
>>>> ACPI abstractions.
>>>>
>>>> Add code to parse those PCC table descriptions associated with an MSC,
>>>> and store the parsed information in the MSC struct.
>>>> There can be multiple PCC channels, and each channel can serve multiple
>>>> MSCs, so we need to keep track of the channel usage, using a list and
>>>> a refcount.
>>>>
>>>> This will be used by the MPAM-Fb access wrapper code.
>>>>
>>>> [1] https://developer.arm.com/documentation/den0144/latest
>>>>
>>>> Signed-off-by: Andre Przywara <[email protected]>
>>>> Tested-by: Ritwick Sharma <[email protected]>
>>> Ritwick gave his Tested-by for the series on v5. Any reason to just add the tag on this patch?
>>
>> submitting-patches.rst says:
>> "Both Tested-by and Reviewed-by tags, once received on mailing list from tester or reviewer, should
>> be added by author to the *applicable* patches when sending next versions."
>>
>> I think this system relies on MPAM-Fb, so he couldn't test each patch in isolation, but "just" that
>> MPAM-Fb works, which is what only patch 10/10 enables.
>>
>> So I find tags given for the whole series always tricky to handle, but in this case I figured patch
>> 10/10 would be the right target.
> 
> Ok, yes. I agree with that principle - I'm still learning how these things are done. Perhaps patch 8
> would have been relevant too.

That's actually a good point, will do this.

Thanks,
Andre

>>> I guess patch 9 has significant enough changes to drop tags but I don't see it for the others.
>>
>> Well, even smaller changes could ruin a whole thing, but IIUC in this case Ritwick's setup doesn't
>> even enable error IRQs, so this part wasn't tested anyway.
> 
> 
>>
>> Cheers,
>> Andre.
>>
>