Re: [PATCH v6 00/40] arm_mpam: Add KVM/arm64 and resctrl glue code

[Ben Horgan]

On 3/13/26 14:45, Ben Horgan wrote:
> This version of the mpam missing pieces series sees a couple of things
> dropped or hidden. Memory bandwith utilization with free-running counters
> is dropped in preference of just always using 'mbm_event' mode (ABMC
> emulation) which simplifies the code and allows for, in the future,
> filtering by read/write traffic. So, for the interim, there is no memory
> bandwidth utilization support. CDP is hidden behind config expert as
> remount of resctrl fs could potentially lead to out of range PARTIDs being
> used and the fix requires a change in fs/resctrl. The setting of MPAM2_EL2
> (for pkvm/nvhe) is dropped as too expensive a write for not much value.
> 
> There are a couple of 'fixes' at the start of the series which address
> problems in the base driver but are only user visible due to this series.
> 
> Changelogs in patches
> 
> Thanks for all the reviewing and testing so far. Just a bit more to get this
> over the line.
> 
> There is a small build conflict with the MPAM abmc precursors series [1], which
> alters some of the resctrl arch hooks. I will shortly be posting a respin
> of that too.
> 
> [1] https://lore.kernel.org/lkml/20260225201905.3568624-1-ben.horgan@xxxxxxx/
> 
> From James' cover letter:
> 
> This is the missing piece to make MPAM usable resctrl in user-space. This has
> shed its debugfs code and the read/write 'event configuration' for the monitors
> to make the series smaller.
> 
Thanks for all the help testing and reviewing. James has now sent a pull request to Catalin and he has picked it up.

Pull request:
https://lore.kernel.org/linux-arm-kernel/01f76011-f3c2-4dcb-b3bc-37c7d4de342e@xxxxxxx/

branch in arm64:
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/mpam

Ben