Re: [RFC] mpam,x86,fs/resctrl: Generic schema description Proof of Concept

From: Chen, Yu C

Date: Wed Jun 10 2026 - 23:27:56 EST


Hi Reinette,

On 6/10/2026 11:59 PM, Reinette Chatre wrote:
Hi Chenyu,


[ ... ]


- This implies that all current and future ERDT capable systems will keep
supporting MSR access with the legacy "percentage based control". Is this
accurate? What will behavior be on an ERDT system that does not support
MSR access with the percentage-based control?

Would it make sense to encourage users to switch to MMIO-based access if the
platform replaces MSR interfaces with MMIO-based ones? One issue with emulating
MSR-based access is that there may not be a strict 1:1 mapping between the MSR
range and the MMIO range. Additionally, I am unsure whether both are strictly
linearly scalable, so it could be challenging to create a proper mapping for
msr_value_emulated = map(mmio_value) IIUC.

thanks,
Chenyu