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| author | Paolo Bonzini <pbonzini@redhat.com> | 2023-09-21 07:49:40 -0400 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2023-09-22 10:55:26 +0200 |
| commit | 7deda2ce5b33edc6d689e429e3fe75382468b030 (patch) | |
| tree | b3e6adcdb4ac6674cd693bbf95a5658f6a459a35 /arch/x86/kernel/cpu/amd.c | |
| parent | ce9ecca0238b140b88f43859b211c9fdfd8e5b70 (diff) | |
| download | linux-7deda2ce5b33edc6d689e429e3fe75382468b030.tar.gz linux-7deda2ce5b33edc6d689e429e3fe75382468b030.tar.bz2 linux-7deda2ce5b33edc6d689e429e3fe75382468b030.zip | |
x86/cpu: Clear SVM feature if disabled by BIOS
When SVM is disabled by BIOS, one cannot use KVM but the
SVM feature is still shown in the output of /proc/cpuinfo.
On Intel machines, VMX is cleared by init_ia32_feat_ctl(),
so do the same on AMD and Hygon processors.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230921114940.957141-1-pbonzini@redhat.com
Diffstat (limited to 'arch/x86/kernel/cpu/amd.c')
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index dd8379d84445..1011ce20f513 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -1031,6 +1031,8 @@ static void zenbleed_check(struct cpuinfo_x86 *c) static void init_amd(struct cpuinfo_x86 *c) { + u64 vm_cr; + early_init_amd(c); /* @@ -1082,6 +1084,14 @@ static void init_amd(struct cpuinfo_x86 *c) init_amd_cacheinfo(c); + if (cpu_has(c, X86_FEATURE_SVM)) { + rdmsrl(MSR_VM_CR, vm_cr); + if (vm_cr & SVM_VM_CR_SVM_DIS_MASK) { + pr_notice_once("SVM disabled (by BIOS) in MSR_VM_CR\n"); + clear_cpu_cap(c, X86_FEATURE_SVM); + } + } + if (!cpu_has(c, X86_FEATURE_LFENCE_RDTSC) && cpu_has(c, X86_FEATURE_XMM2)) { /* * Use LFENCE for execution serialization. On families which |