linux-kernel - RE: [PATCH 1/6] x86/cpu: Break Vendor/Family/Model macros into separate header

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Message-ID: <DS7PR11MB6077A36D7BC6832E3ACEA1B2FC63A@DS7PR11MB6077.namprd11.prod.outlook.com>
Date: Wed, 11 Feb 2026 22:21:47 +0000
From: "Luck, Tony" <tony.luck@...el.com>
To: "Hansen, Dave" <dave.hansen@...el.com>, "Mehta, Sohil"
	<sohil.mehta@...el.com>
CC: Dave Hansen <dave.hansen@...ux.intel.com>, "Liu, Zhao1"
	<zhao1.liu@...el.com>, Borislav Petkov <bp@...en8.de>, "H. Peter Anvin"
	<hpa@...or.com>, Ingo Molnar <mingo@...hat.com>, "Kohler, Jon"
	<jon@...anix.com>, Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>, "Peter
 Zijlstra (Intel)" <peterz@...radead.org>, Thomas Gleixner <tglx@...nel.org>,
	"x86@...nel.org" <x86@...nel.org>, "Winiarska, Iwona"
	<iwona.winiarska@...el.com>, LKML <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/6] x86/cpu: Break Vendor/Family/Model macros into
 separate header

> But we basically never care about the format that's in CPUID.01H:EAX.

> The PECI code has none of that. It's *just* matching the "id" of the
> device to the "id" of the CPU. It just so happens that the "id" that's
> chosen matches CPUID.01H:EAX.

> So PECI and x86 both want the same data, but they do very different
> things with it.

> So let's just duplicate the constants. Completely untested patch attached.

> Any reason not to do this?

PECI code doesn't care about the stepping. You drop it when initializing
the device_id:

+	device->info.device_id = cpu_id >> 4;

But then you defined all the PECI model constants with the stepping.
E.g.

+#define PECI_INTEL_HASWELL_X		0x306C0

Perhaps drop the trailing '0' nibble and add a comment about the ID
being stepping independent?

-Tony