linux-kernel - x86/apic: Drop useless CXL/CPX row from the TSC deadline errata table

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Message-Id: <20250716160824.2167709-1-andrew.cooper3@citrix.com>
Date: Wed, 16 Jul 2025 17:08:24 +0100
From: Andrew Cooper <andrew.cooper3@...rix.com>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Andrew Cooper <andrew.cooper3@...rix.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Sohil Mehta <sohil.mehta@...el.com>,
	Yuntao Wang <yuntao.wang@...ux.dev>,
	Zhang Rui <rui.zhang@...el.com>
Subject: x86/apic: Drop useless CXL/CPX row from the TSC deadline errata table

A microcode revision of 0 is guaranteed to exit apic_validate_deadline_timer()
early, but a better way is with no row at all.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@...rix.com>
---
CC: Thomas Gleixner <tglx@...utronix.de>
CC: Ingo Molnar <mingo@...hat.com>
CC: Borislav Petkov <bp@...en8.de>
CC: Dave Hansen <dave.hansen@...ux.intel.com>
CC: x86@...nel.org
CC: "H. Peter Anvin" <hpa@...or.com>
CC: Peter Zijlstra <peterz@...radead.org>
CC: Sohil Mehta <sohil.mehta@...el.com>
CC: Yuntao Wang <yuntao.wang@...ux.dev>
CC: Zhang Rui <rui.zhang@...el.com>
CC: linux-kernel@...r.kernel.org

Strictly speaking, this is:

  Fixes: 66abf2388331 ("x86/apic: Convert the TSC deadline timer matching to steppings macro")

but I really don't think it's interesting to backport.

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index d73ba5a7b623..6ace71c52bee 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -522,7 +522,6 @@ static const struct x86_cpu_id deadline_match[] __initconst = {
 
 	X86_MATCH_VFM_STEPS(INTEL_SKYLAKE_X,   0x3, 0x3, 0x01000136),
 	X86_MATCH_VFM_STEPS(INTEL_SKYLAKE_X,   0x4, 0x4, 0x02000014),
-	X86_MATCH_VFM_STEPS(INTEL_SKYLAKE_X,   0x5, 0xf, 0),
 
 	X86_MATCH_VFM(INTEL_HASWELL,		0x22),
 	X86_MATCH_VFM(INTEL_HASWELL_L,		0x20),