linux-kernel - [PATCH 1/2] KVM: SVM: Implement check_nested

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Message-Id: <20200414201107.22952-2-cavery@redhat.com>
Date:   Tue, 14 Apr 2020 16:11:06 -0400
From:   Cathy Avery <cavery@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        pbonzini@...hat.com
Cc:     vkuznets@...hat.com, wei.huang2@....com
Subject: [PATCH 1/2] KVM: SVM: Implement check_nested_events for NMI

Migrate nested guest NMI intercept processing
to new check_nested_events.

Signed-off-by: Cathy Avery <cavery@...hat.com>
---
 arch/x86/kvm/svm/nested.c | 21 +++++++++++++++++++++
 arch/x86/kvm/svm/svm.c    |  2 +-
 arch/x86/kvm/svm/svm.h    | 15 ---------------
 3 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 90a1ca939627..1ba8ef46b0b5 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -764,6 +764,20 @@ int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
 	return vmexit;
 }
 
+static bool nested_exit_on_nmi(struct vcpu_svm *svm)
+{
+	return (svm->nested.intercept & (1ULL << INTERCEPT_NMI));
+}
+
+static void nested_svm_nmi(struct vcpu_svm *svm)
+{
+	svm->vmcb->control.exit_code = SVM_EXIT_NMI;
+	svm->vmcb->control.exit_info_1 = 0;
+	svm->vmcb->control.exit_info_2 = 0;
+
+	svm->nested.exit_required = true;
+}
+
 static void nested_svm_intr(struct vcpu_svm *svm)
 {
 	svm->vmcb->control.exit_code   = SVM_EXIT_INTR;
@@ -793,6 +807,13 @@ int svm_check_nested_events(struct kvm_vcpu *vcpu)
 		return 0;
 	}
 
+	if (vcpu->arch.nmi_pending && nested_exit_on_nmi(svm)) {
+		if (block_nested_events)
+			return -EBUSY;
+		nested_svm_nmi(svm);
+		return 0;
+	}
+
 	return 0;
 }
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 2be5bbae3a40..84c338c55348 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3053,7 +3053,7 @@ static int svm_nmi_allowed(struct kvm_vcpu *vcpu)
 	int ret;
 	ret = !(vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) &&
 	      !(svm->vcpu.arch.hflags & HF_NMI_MASK);
-	ret = ret && gif_set(svm) && nested_svm_nmi(svm);
+	ret = ret && gif_set(svm);
 
 	return ret;
 }
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index df3474f4fb02..9be2b890ff3c 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -369,21 +369,6 @@ void disable_nmi_singlestep(struct vcpu_svm *svm);
 #define NESTED_EXIT_DONE	1	/* Exit caused nested vmexit  */
 #define NESTED_EXIT_CONTINUE	2	/* Further checks needed      */
 
-/* This function returns true if it is save to enable the nmi window */
-static inline bool nested_svm_nmi(struct vcpu_svm *svm)
-{
-	if (!is_guest_mode(&svm->vcpu))
-		return true;
-
-	if (!(svm->nested.intercept & (1ULL << INTERCEPT_NMI)))
-		return true;
-
-	svm->vmcb->control.exit_code = SVM_EXIT_NMI;
-	svm->nested.exit_required = true;
-
-	return false;
-}
-
 static inline bool svm_nested_virtualize_tpr(struct kvm_vcpu *vcpu)
 {
 	return is_guest_mode(vcpu) && (vcpu->arch.hflags & HF_VINTR_MASK);
-- 
2.20.1