linux-kernel - [PATCH 5.4 063/222] x86/CPU/AMD: Ensure clearing of SME/SEV features is maintained

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Message-Id: <20200122092838.232080512@linuxfoundation.org>
Date:   Wed, 22 Jan 2020 10:27:29 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Tom Lendacky <thomas.lendacky@....com>,
        Borislav Petkov <bp@...e.de>
Subject: [PATCH 5.4 063/222] x86/CPU/AMD: Ensure clearing of SME/SEV features is maintained

From: Tom Lendacky <thomas.lendacky@....com>

commit a006483b2f97af685f0e60f3a547c9ad4c9b9e94 upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/kernel/cpu/amd.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -615,9 +615,9 @@ static void early_detect_mem_encrypt(str
 		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);
 	}
 }