Re: [PATCH] arm_mpam: Fix software reset values of MPAMCFG_PRI

[Will Deacon]

On Fri, 15 May 2026 09:58:25 +0100, Ben Horgan wrote:
> Priority partitioning is not supported other than to set the per-PARTID
> defaults in MPAMCFG_PRI, INTPRI and DSPRI, to the highest priority. When 0
> is the lowest priority, all ones is the highest priority. However, these
> values are calculated with an extra higher bit set.
> 
> Luckily, there is still no chance of setting functional bits incorrectly.
> When the priority widths are maximal, this is ensured as the fields have
> width 16 and a u16 holds the value for each field. When the widths are
> smaller, the higher order bits beyond the advertised widths,
> MPAMF_PRI_IDR.DSPRI_WD and MPAMF_PRI_IDR.INTPRI_WD, in the priority fields
> INTPRI and DSPRI are not used to calculate the priority.  It is not
> specified whether these higher order bits are RAZ/WI or Res0 and so it is
> desirable not to set them to avoid the chance of misleading reads.
> 
> [...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm_mpam: Fix software reset values of MPAMCFG_PRI
      https://git.kernel.org/arm64/c/9469764292e0

Cheers,
-- 
Will

https://fixes.arm64.dev
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