linux-kernel - [tip: x86/urgent] x86/CPU/AMD: Ensure clearing of SME/SEV features is maintained

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

Message-ID: <157920281894.396.1775591603409814126.tip-bot2@tip-bot2>
Date:   Thu, 16 Jan 2020 19:26:58 -0000
From:   "tip-bot2 for Tom Lendacky" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Tom Lendacky <thomas.lendacky@....com>,
        Borislav Petkov <bp@...e.de>, <stable@...r.kernel.org>,
        x86 <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: [tip: x86/urgent] x86/CPU/AMD: Ensure clearing of SME/SEV features is
 maintained

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

Commit-ID:     a006483b2f97af685f0e60f3a547c9ad4c9b9e94
Gitweb:        https://git.kernel.org/tip/a006483b2f97af685f0e60f3a547c9ad4c9b9e94
Author:        Tom Lendacky <thomas.lendacky@....com>
AuthorDate:    Wed, 15 Jan 2020 16:05:16 -06:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Thu, 16 Jan 2020 20:23:20 +01:00

x86/CPU/AMD: Ensure clearing of SME/SEV features is maintained

If the SME and SEV features are present via CPUID, but memory encryption
support is not enabled (MSR 0xC001_0010[23]), the feature flags are cleared
using clear_cpu_cap(). However, if get_cpu_cap() is later called, these
feature flags will be reset back to present, which is not desired.

Change from using clear_cpu_cap() to setup_clear_cpu_cap() so that the
clearing of the flags is maintained.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: <stable@...r.kernel.org> # 4.16.x-
Link: https://lkml.kernel.org/r/226de90a703c3c0be5a49565047905ac4e94e8f3.1579125915.git.thomas.lendacky@amd.com
---
 arch/x86/kernel/cpu/amd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 90f75e5..62c3027 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -615,9 +615,9 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c)
 		return;
 
 clear_all:
-		clear_cpu_cap(c, X86_FEATURE_SME);
+		setup_clear_cpu_cap(X86_FEATURE_SME);
 clear_sev:
-		clear_cpu_cap(c, X86_FEATURE_SEV);
+		setup_clear_cpu_cap(X86_FEATURE_SEV);
 	}
 }