Re: [PATCH v6 00/10] arm_mpam: Add MPAM-Fb firmware support

Hi Andre,

On 7/30/26 16:25, Andre Przywara wrote:
[...]
> The first six patches rework all MSC access wrappers to propagate error
> information. Pure MMIO based MSC accesses would never fail, but the
> MPAM-Fb access can go wrong in multiple ways. The patches have been split
> up purely for reviewing reasons, if the number is a problem, we could as
> well squash them. Please note that until the very last patch of this series
> any MSC accesses would always only return 0, it's only the final enablement
> of MPAM-Fb that could possibly introduce errors. Hence all former patches
> can add error handling gradually, those code paths wouldn't be triggered
> before patch 10/10.

I had a go at injecting some errors and noticed that at least some aren't getting to user space.
When writing the schemata file any MPAM-Fb error is not propagated to the user. The
resctrl_arch_update_domains() continues to return 0 as there are some missing links in the chain
down to the writes, e.g. __write_config() always returns 0.

Thanks,

Ben