linux-kernel - Re: [PATCH v5 03/10] platform/x86/intel/ifs: Add stub driver for In-Field Scan

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Date:   Wed, 04 May 2022 12:35:30 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Tony Luck <tony.luck@...el.com>, hdegoede@...hat.com,
        markgross@...nel.org
Cc:     mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
        x86@...nel.org, hpa@...or.com, corbet@....net,
        gregkh@...uxfoundation.org, andriy.shevchenko@...ux.intel.com,
        jithu.joseph@...el.com, ashok.raj@...el.com, tony.luck@...el.com,
        rostedt@...dmis.org, dan.j.williams@...el.com,
        linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        platform-driver-x86@...r.kernel.org, patches@...ts.linux.dev,
        ravi.v.shankar@...el.com
Subject: Re: [PATCH v5 03/10] platform/x86/intel/ifs: Add stub driver for
 In-Field Scan

On Thu, Apr 28 2022 at 08:38, Tony Luck wrote:
> +#define X86_MATCH(model)				\
> +	X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 6,	\
> +		INTEL_FAM6_##model, X86_FEATURE_CORE_CAPABILITIES, NULL)
> +
> +static const struct x86_cpu_id ifs_cpu_ids[] __initconst = {
> +	X86_MATCH(SAPPHIRERAPIDS_X),

Why do we need a model match here? The core capabilities MSR is only
available when X86_FEATURE_CORE_CAPABILITIES is set:

    "If CPUID.(EAX=07H, ECX=0):EDX[30] = 1.
     This MSR provides an architectural enumeration
     function for model-specific behavior."

So checking for Intel Fam6 ANYMODEL and X86_FEATURE_CORE_CAPABILITIES is
sufficient, no?

We really don't need more match id tables with gazillions of CPU models.

Thanks,

        tglx