Commit ee785c87 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: nSVM: Use KVM-governed feature framework to track "vNMI enabled" 

Track "virtual NMI exposed to L1" via a governed feature flag instead of
using a dedicated bit/flag in vcpu_svm.

Note, checking KVM's capabilities instead of the "vnmi" param means that
the code isn't strictly equivalent, as vnmi_enabled could have been set
if nested=false where as that the governed feature cannot.  But that's a
glorified nop as the feature/flag is consumed only by paths that are
gated by nSVM being enabled.

Link: https://lore.kernel.org/r/20230815203653.519297-15-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent b89456ae

arch/x86/kvm/governed_features.h

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ KVM_GOVERNED_X86_FEATURE(LBRV) 
KVM_GOVERNED_X86_FEATURE(PAUSEFILTER)

KVM_GOVERNED_X86_FEATURE(PFTHRESHOLD)

KVM_GOVERNED_X86_FEATURE(VGIF)

KVM_GOVERNED_X86_FEATURE(VNMI)



#undef KVM_GOVERNED_X86_FEATURE

#undef KVM_GOVERNED_FEATURE

arch/x86/kvm/svm/svm.c

+1 −2
Original line number Diff line number Diff line
@@ -4274,8 +4274,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) 
	kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_PAUSEFILTER);

	kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_PFTHRESHOLD);

	kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_VGIF);



	svm->vnmi_enabled = vnmi && guest_cpuid_has(vcpu, X86_FEATURE_VNMI);

	kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_VNMI);



	svm_recalc_instruction_intercepts(vcpu, svm);

arch/x86/kvm/svm/svm.h

+1 −4
Original line number Diff line number Diff line
@@ -259,9 +259,6 @@ struct vcpu_svm { 
	unsigned long soft_int_next_rip;

	bool soft_int_injected;



	/* optional nested SVM features that are enabled for this guest  */

	bool vnmi_enabled                 : 1;



	u32 ldr_reg;

	u32 dfr_reg;

	struct page *avic_backing_page;
@@ -537,7 +534,7 @@ static inline bool nested_npt_enabled(struct vcpu_svm *svm) 


static inline bool nested_vnmi_enabled(struct vcpu_svm *svm)

{

	return svm->vnmi_enabled &&

	return guest_can_use(&svm->vcpu, X86_FEATURE_VNMI) &&

	       (svm->nested.ctl.int_ctl & V_NMI_ENABLE_MASK);

}