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| author | Paolo Bonzini <pbonzini@redhat.com> | 2021-04-21 19:11:15 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-04-26 05:27:15 -0400 |
| commit | d9db0fd6c5c9fa7c9a462a2c54d5e91455a74fca (patch) | |
| tree | 44ca9d2af91b6486a802b4f32d188f191f6b74e3 /arch/x86/kvm/cpuid.c | |
| parent | e8126bdaf19400050a57a2c1662a22786b9426f1 (diff) | |
| download | linux-d9db0fd6c5c9fa7c9a462a2c54d5e91455a74fca.tar.gz linux-d9db0fd6c5c9fa7c9a462a2c54d5e91455a74fca.tar.bz2 linux-d9db0fd6c5c9fa7c9a462a2c54d5e91455a74fca.zip | |
KVM: SEV: Mask CPUID[0x8000001F].eax according to supported features
Add a reverse-CPUID entry for the memory encryption word, 0x8000001F.EAX,
and use it to override the supported CPUID flags reported to userspace.
Masking the reported CPUID flags avoids over-reporting KVM support, e.g.
without the mask a SEV-SNP capable CPU may incorrectly advertise SNP
support to userspace.
Clear SEV/SEV-ES if their corresponding module parameters are disabled,
and clear the memory encryption leaf completely if SEV is not fully
supported in KVM. Advertise SME_COHERENT in addition to SEV and SEV-ES,
as the guest can use SME_COHERENT to avoid CLFLUSH operations.
Explicitly omit SME and VM_PAGE_FLUSH from the reporting. These features
are used by KVM, but are not exposed to the guest, e.g. guest access to
related MSRs will fault.
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210422021125.3417167-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 8e3033fe91c3..e9d644147bf5 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -558,6 +558,10 @@ void kvm_set_cpu_caps(void) */ kvm_cpu_cap_mask(CPUID_8000_000A_EDX, 0); + kvm_cpu_cap_mask(CPUID_8000_001F_EAX, + 0 /* SME */ | F(SEV) | 0 /* VM_PAGE_FLUSH */ | F(SEV_ES) | + F(SME_COHERENT)); + kvm_cpu_cap_mask(CPUID_C000_0001_EDX, F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) | F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) | @@ -945,8 +949,10 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) break; /* Support memory encryption cpuid if host supports it */ case 0x8000001F: - if (!boot_cpu_has(X86_FEATURE_SEV)) + if (!kvm_cpu_cap_has(X86_FEATURE_SEV)) entry->eax = entry->ebx = entry->ecx = entry->edx = 0; + else + cpuid_entry_override(entry, CPUID_8000_001F_EAX); break; /*Add support for Centaur's CPUID instruction*/ case 0xC0000000: |