Re: [PATCH v12 02/25] x86/resctrl: Check if monitoring features are supported

[Reinette Chatre]

Hi Tony,

On 9/16/26 4:12 PM, Tony Luck wrote:
> Both Intel and AMD manuals say that software must first check
> CPUID(0x7,0x0).EBX[12] (Linux: X86_FEATURE_CQM) to see if any monitoring

The "Linux:" caveat (here and below) seems unnecessary?

> features are supported before checking for specific features supported

To connect with the text that follows "specific features" could be
"resource specific monitoring features" ...

> in subleaves.
> 
> Each of the L3-based monitoring features is further gated by

... then "L3-based monitoring features" could be "L3 resource monitoring
features".

> CPUID(0xF,0x0).EDX[1] (Linux: X86_FEATURE_CQM_LLC).
> 
> Add checks for these feature bits.
> 
> Fixes: cbc82b172638 ("x86: Add support for Intel Cache QoS Monitoring (CQM) detection")
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
> ---

To help move this along it may be useful to add a note in "maintainer" section
that, even though this is a fix, it is not targeting stable (and why).

| Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>

Reinette