[PATCH v4 01/15] KVM: SVM: Invert handling of SEV and SEV_ES feature flags

From: Paolo Bonzini
Date: Mon Mar 18 2024 - 19:34:12 EST


From: Sean Christopherson <seanjc@xxxxxxxxxx>

Leave SEV and SEV_ES '0' in kvm_cpu_caps by default, and instead set them
in sev_set_cpu_caps() if SEV and SEV-ES support are fully enabled. Aside
from the fact that sev_set_cpu_caps() is wildly misleading when it *clears*
capabilities, this will allow compiling out sev.c without falsely
advertising SEV/SEV-ES support in KVM_GET_SUPPORTED_CPUID.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Reviewed-by: Michael Roth <michael.roth@xxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 2 +-
arch/x86/kvm/svm/sev.c | 8 ++++----
2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index adba49afb5fe..bde4df13a7e8 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -761,7 +761,7 @@ 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) |
+ 0 /* SME */ | 0 /* SEV */ | 0 /* VM_PAGE_FLUSH */ | 0 /* SEV_ES */ |
F(SME_COHERENT));

kvm_cpu_cap_mask(CPUID_8000_0021_EAX,
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index e5a4d9b0e79f..382c745b8ba9 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2186,10 +2186,10 @@ void sev_vm_destroy(struct kvm *kvm)

void __init sev_set_cpu_caps(void)
{
- if (!sev_enabled)
- kvm_cpu_cap_clear(X86_FEATURE_SEV);
- if (!sev_es_enabled)
- kvm_cpu_cap_clear(X86_FEATURE_SEV_ES);
+ if (sev_enabled)
+ kvm_cpu_cap_set(X86_FEATURE_SEV);
+ if (sev_es_enabled)
+ kvm_cpu_cap_set(X86_FEATURE_SEV_ES);
}

void __init sev_hardware_setup(void)
--
2.43.0