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

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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: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2023-08-15 13:36:52 -07:00
parent b89456aee7
commit ee785c870d
3 changed files with 3 additions and 6 deletions
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1
arch/x86/kvm/governed_features.h
View File

@ -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

3
arch/x86/kvm/svm/svm.c
View File

@ -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);

5
arch/x86/kvm/svm/svm.h
View File

@ -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);
}