[PATCH v10 3/9] KVM: x86: Use KVM-governed feature framework to track "LAM enabled"

[Binbin Wu]

Use the governed feature framework to track if Linear Address Masking (LAM)
is "enabled", i.e. if LAM can be used by the guest. So that guest_can_use()
can be used to support LAM virtualization.

LAM modifies the checking that is applied to 64-bit linear addresses, allowing
software to use of the untranslated address bits for metadata and masks the
metadata bits before using them as linear addresses to access memory.

Signed-off-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
---
 arch/x86/kvm/governed_features.h | 2 ++
 arch/x86/kvm/vmx/vmx.c           | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h
index 40ce8e6608cd..708578d60e6f 100644
--- a/arch/x86/kvm/governed_features.h
+++ b/arch/x86/kvm/governed_features.h
@@ -5,5 +5,7 @@ BUILD_BUG()
 
 #define KVM_GOVERNED_X86_FEATURE(x) KVM_GOVERNED_FEATURE(X86_FEATURE_##x)
 
+KVM_GOVERNED_X86_FEATURE(LAM)
+
 #undef KVM_GOVERNED_X86_FEATURE
 #undef KVM_GOVERNED_FEATURE
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 0ecf4be2c6af..ae47303c88d7 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7783,6 +7783,9 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 		vmx->msr_ia32_feature_control_valid_bits &=
 			~FEAT_CTL_SGX_LC_ENABLED;
 
+	if (boot_cpu_has(X86_FEATURE_LAM))
+		kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_LAM);
+
 	/* Refresh #PF interception to account for MAXPHYADDR changes. */
 	vmx_update_exception_bitmap(vcpu);
 }
-- 
2.25.1