linux-kernel - [tip: x86/urgent] x86/CPU/AMD: Disable INVLPGB on Zen2

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Message-ID: <175198623117.406.3528096569299632559.tip-bot2@tip-bot2>
Date: Tue, 08 Jul 2025 14:50:31 -0000
From: "tip-bot2 for Mikhail Paulyshka" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Mikhail Paulyshka <me@...aill.net>, "Borislav Petkov (AMD)" <bp@...en8.de>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/CPU/AMD: Disable INVLPGB on Zen2

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     5a97aa3a4f1f19656aea5c76c1da66ce9dc5ddaf
Gitweb:        https://git.kernel.org/tip/5a97aa3a4f1f19656aea5c76c1da66ce9dc5ddaf
Author:        Mikhail Paulyshka <me@...aill.net>
AuthorDate:    Tue, 08 Jul 2025 16:39:10 +02:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Tue, 08 Jul 2025 16:41:59 +02:00

x86/CPU/AMD: Disable INVLPGB on Zen2

AMD Cyan Skillfish (Family 17h, Model 47h, Stepping 0h) has an issue
that causes system oopses and panics when performing TLB flush using
INVLPGB.

However, the problem is that that machine has misconfigured CPUID and
should not report the INVLPGB bit in the first place. So zap the
kernel's representation of the flag so that nothing gets confused.

  [ bp: Massage. ]

Signed-off-by: Mikhail Paulyshka <me@...aill.net>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Link: https://lore.kernel.org/r/1ebe845b-322b-4929-9093-b41074e9e939@mixaill.net
---
 arch/x86/kernel/cpu/amd.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index e1c4661..1b1ff60 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -937,6 +937,9 @@ static void init_amd_zen2(struct cpuinfo_x86 *c)
 		msr_clear_bit(MSR_AMD64_CPUID_FN_7, 18);
 		pr_emerg("RDSEED is not reliable on this platform; disabling.\n");
 	}
+
+	/* Correct misconfigured CPUID on some clients. */
+	clear_cpu_cap(c, X86_FEATURE_INVLPGB);
 }
 
 static void init_amd_zen3(struct cpuinfo_x86 *c)