Re: [PATCH v13 03/25] x86/resctrl: Check if monitoring features are supported

[Chen Yu]

On Mon, Sep 28, 2026 at 03:14:47PM -0700, Tony Luck wrote:
> Both Intel and AMD manuals say that software must first check
> CPUID(0x7,0x0).EBX[12] to see if any monitoring features are supported before
> checking for resource specific features supported in subleaves.
> 
> Each of the L3 monitoring features is further gated by CPUID(0xF,0x0).EDX[1].
> 
> Add checks for these feature bits.
> 
> Maintainer note: No need to backport this fix. No issues have been seen
> from this failure to follow the exact enumeration process in the manual.
> 
> Fixes: cbc82b172638 ("x86: Add support for Intel Cache QoS Monitoring (CQM) detection")
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>

Apply MMIO-based CMT patches on top of this one,

Tested-by: Chen Yu <yu.c.chen@xxxxxxxxx>

thanks,
Chenyu