If the SME and SEV features are present via CPUID, but memory encryption support is not enabled (MSR 0xC001_0010[23]), the features are cleared using clear_cpu_cap(). However, if get_cpu_cap() is later called, these features 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 features is maintained.
Cc: stable@vger.kernel.org # 4.16.x- Signed-off-by: Tom Lendacky 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 90f75e515876..62c30279be77 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); } }
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@amd.com AuthorDate: Wed, 15 Jan 2020 16:05:16 -06:00 Committer: Borislav Petkov bp@suse.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@amd.com Signed-off-by: Borislav Petkov bp@suse.de Cc: stable@vger.kernel.org # 4.16.x- Link: https://lkml.kernel.org/r/226de90a703c3c0be5a49565047905ac4e94e8f3.157912591... --- 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); } }
On Wed, Jan 15, 2020 at 04:05:16PM -0600, Tom Lendacky wrote:
If the SME and SEV features are present via CPUID, but memory encryption support is not enabled (MSR 0xC001_0010[23]), the features are cleared using clear_cpu_cap(). However, if get_cpu_cap() is later called, these features 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 features is maintained.
Cc: stable@vger.kernel.org # 4.16.x- Signed-off-by: Tom Lendacky thomas.lendacky@amd.com
Reviewed-by: Joerg Roedel jroedel@suse.de
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 90f75e515876..62c30279be77 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);} -- 2.17.1
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