linux-kernel - Re: [PATCH 3/6] x86/microcode: Refactor platform ID enumeration into a helper

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Message-ID: <bc336820-2d0a-4ebc-9081-cbfc109deb8d@intel.com>
Date: Tue, 10 Feb 2026 15:20:41 -0800
From: Sohil Mehta <sohil.mehta@...el.com>
To: Dave Hansen <dave.hansen@...ux.intel.com>, <linux-kernel@...r.kernel.org>
CC: <zhao1.liu@...el.com>, Borislav Petkov <bp@...en8.de>, "H. Peter Anvin"
	<hpa@...or.com>, Ingo Molnar <mingo@...hat.com>, Jon Kohler
	<jon@...anix.com>, Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>, "Peter
 Zijlstra (Intel)" <peterz@...radead.org>, Thomas Gleixner <tglx@...nel.org>,
	Tony Luck <tony.luck@...el.com>, <x86@...nel.org>
Subject: Re: [PATCH 3/6] x86/microcode: Refactor platform ID enumeration into
 a helper

On 2/6/2026 3:14 PM, Dave Hansen wrote:

>  b/arch/x86/include/asm/microcode.h      |   32 ++++++++++++++++++++++++++++++++
>  b/arch/x86/kernel/cpu/microcode/intel.c |   10 +---------
>  2 files changed, 33 insertions(+), 9 deletions(-)
> 

Reviewed-by: Sohil Mehta <sohil.mehta@...el.com>

A minor nit:

> -	if (IFM(x86_family(sig->sig), x86_model(sig->sig)) >= INTEL_PENTIUM_III_DESCHUTES) {
> -		unsigned int val[2];
> -
> -		/* get processor flags from MSR 0x17 */
> -		native_rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
> -		sig->pf = 1 << ((val[1] >> 18) & 7);
> -	}
> +	sig->pf  = 1 << intel_get_platform_id();

How about BIT(intel_get_platform_id())?

>  }
>  EXPORT_SYMBOL_GPL(intel_collect_cpu_info);
>  
> _