[PATCHv4 04/11] KVM: SVM: add wrappers to enable/disable IRET interception

Santosh Shukla
2023-02-27T08:55:11Z

From: Maxim Levitsky <mlevitsk@redhat.com>

SEV-ES guests don't use IRET interception for the detection of
an end of a NMI.

Therefore it makes sense to create a wrapper to avoid repeating
the check for the SEV-ES.

No functional change is intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
[Renamed iret intercept API of style svm_{clr,set}_iret_intercept()]
Signed-off-by: Santosh Shukla <Santosh.Shukla@amd.com>
---
v3:
- renamed iret_intercept API
https://lore.kernel.org/all/a5d8307b-ffe6-df62-5e22-dffd19755baa@amd.com/

arch/x86/kvm/svm/svm.c | 28 +++++++++++++++++++---------
1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index cf6ae093ed19..da936723e8ca 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2490,16 +2490,29 @@ static int task_switch_interception(struct kvm_vcpu *vcpu)
has_error_code, error_code);
}

+static void svm_clr_iret_intercept(struct vcpu_svm *svm)
+{
+ if (!sev_es_guest(svm->vcpu.kvm))
+ svm_clr_intercept(svm, INTERCEPT_IRET);
+}
+
+static void svm_set_iret_intercept(struct vcpu_svm *svm)
+{
+ if (!sev_es_guest(svm->vcpu.kvm))
+ svm_set_intercept(svm, INTERCEPT_IRET);
+}
+
static int iret_interception(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);

++vcpu->stat.nmi_window_exits;
svm->awaiting_iret_completion = true;
- if (!sev_es_guest(vcpu->kvm)) {
- svm_clr_intercept(svm, INTERCEPT_IRET);
+
+ svm_clr_iret_intercept(svm);
+ if (!sev_es_guest(vcpu->kvm))
svm->nmi_iret_rip = kvm_rip_read(vcpu);
- }
+
kvm_make_request(KVM_REQ_EVENT, vcpu);
return 1;
}
@@ -3491,8 +3504,7 @@ static void svm_inject_nmi(struct kvm_vcpu *vcpu)
return;

svm->nmi_masked = true;
- if (!sev_es_guest(vcpu->kvm))
- svm_set_intercept(svm, INTERCEPT_IRET);
+ svm_set_iret_intercept(svm);
++vcpu->stat.nmi_injections;
}

@@ -3632,12 +3644,10 @@ static void svm_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)

if (masked) {
svm->nmi_masked = true;
- if (!sev_es_guest(vcpu->kvm))
- svm_set_intercept(svm, INTERCEPT_IRET);
+ svm_set_iret_intercept(svm);
} else {
svm->nmi_masked = false;
- if (!sev_es_guest(vcpu->kvm))
- svm_clr_intercept(svm, INTERCEPT_IRET);
+ svm_clr_iret_intercept(svm);
}
}

--
2.25.1