linux-kernel - [tip: x86/urgent] x86/cpu: Fix PPIN initialization

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <173252681739.412.4757446080039715116.tip-bot2@tip-bot2>
Date: Mon, 25 Nov 2024 09:26:57 -0000
From: "tip-bot2 for Tony Luck" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Adeel Ashad <adeel.arshad@...el.com>, Tony Luck <tony.luck@...el.com>,
 Ingo Molnar <mingo@...nel.org>, x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/cpu: Fix PPIN initialization

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

Commit-ID:     d9bb40544653cf039fe79225ec1d742183e2339a
Gitweb:        https://git.kernel.org/tip/d9bb40544653cf039fe79225ec1d742183e2339a
Author:        Tony Luck <tony.luck@...el.com>
AuthorDate:    Fri, 22 Nov 2024 15:42:12 -08:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Mon, 25 Nov 2024 10:11:33 +01:00

x86/cpu: Fix PPIN initialization

On systems that enumerate PPIN (protected processor inventory
number) using CPUID, but where the BIOS locked the MSR to
prevent access /proc/cpuinfo reports "intel_ppin" feature as
present on all logical CPUs except for CPU 0.

This happens because ppin_init() uses x86_match_cpu() to
determine whether PPIN is supported. When called on CPU 0
the test for locked PPIN MSR results in:

	clear_cpu_cap(c, info->feature);

This clears the X86 FEATURE bit in boot_cpu_data. When other
CPUs are brought online the x86_match_cpu() fails, and the
PPIN FEATURE bit remains set for those other CPUs.

Fix by using setup_clear_cpu_cap() instead of clear_cpu_cap()
which force clears the FEATURE bit for all CPUS.

Reported-by: Adeel Ashad <adeel.arshad@...el.com>
Signed-off-by: Tony Luck <tony.luck@...el.com>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Link: https://lore.kernel.org/r/20241122234212.27451-1-tony.luck@intel.com
---
 arch/x86/kernel/cpu/common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 06a516f..d9d2d19 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -169,7 +169,7 @@ static void ppin_init(struct cpuinfo_x86 *c)
 	}

 clear_ppin:
-	clear_cpu_cap(c, info->feature);
+	setup_clear_cpu_cap(info->feature);
 }

 static void default_init(struct cpuinfo_x86 *c)