linux-kernel - [PATCH 2/2] KVM: nSVM: Add helper to synthesize nested VM-Exit without collateral

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Date:   Tue,  2 Mar 2021 09:45:15 -0800
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: [PATCH 2/2] KVM: nSVM: Add helper to synthesize nested VM-Exit
 without collateral

Add a helper to consolidate boilerplate for nested VM-Exits that don't
provide any data in exit_info_*.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/svm/nested.c | 55 +++++----------------------------------
 arch/x86/kvm/svm/svm.c    |  6 +----
 arch/x86/kvm/svm/svm.h    |  9 +++++++
 3 files changed, 16 insertions(+), 54 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 93a61ed76e5b..307c11125391 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -797,12 +797,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 
 static void nested_svm_triple_fault(struct kvm_vcpu *vcpu)
 {
-	struct vcpu_svm *svm = to_svm(vcpu);
-
-	svm->vmcb->control.exit_code   = SVM_EXIT_SHUTDOWN;
-	svm->vmcb->control.exit_info_1 = 0;
-	svm->vmcb->control.exit_info_2 = 0;
-	nested_svm_vmexit(svm);
+	nested_svm_simple_vmexit(to_svm(vcpu), SVM_EXIT_SHUTDOWN);
 }
 
 int svm_allocate_nested(struct vcpu_svm *svm)
@@ -1027,50 +1022,11 @@ static void nested_svm_inject_exception_vmexit(struct vcpu_svm *svm)
 	nested_svm_vmexit(svm);
 }
 
-static void nested_svm_smi(struct vcpu_svm *svm)
-{
-	svm->vmcb->control.exit_code = SVM_EXIT_SMI;
-	svm->vmcb->control.exit_info_1 = 0;
-	svm->vmcb->control.exit_info_2 = 0;
-
-	nested_svm_vmexit(svm);
-}
-
-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;
-
-	nested_svm_vmexit(svm);
-}
-
-static void nested_svm_intr(struct vcpu_svm *svm)
-{
-	trace_kvm_nested_intr_vmexit(svm->vmcb->save.rip);
-
-	svm->vmcb->control.exit_code   = SVM_EXIT_INTR;
-	svm->vmcb->control.exit_info_1 = 0;
-	svm->vmcb->control.exit_info_2 = 0;
-
-	nested_svm_vmexit(svm);
-}
-
 static inline bool nested_exit_on_init(struct vcpu_svm *svm)
 {
 	return vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_INIT);
 }
 
-static void nested_svm_init(struct vcpu_svm *svm)
-{
-	svm->vmcb->control.exit_code   = SVM_EXIT_INIT;
-	svm->vmcb->control.exit_info_1 = 0;
-	svm->vmcb->control.exit_info_2 = 0;
-
-	nested_svm_vmexit(svm);
-}
-
-
 static int svm_check_nested_events(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -1084,7 +1040,7 @@ static int svm_check_nested_events(struct kvm_vcpu *vcpu)
 			return -EBUSY;
 		if (!nested_exit_on_init(svm))
 			return 0;
-		nested_svm_init(svm);
+		nested_svm_simple_vmexit(svm, SVM_EXIT_INIT);
 		return 0;
 	}
 
@@ -1102,7 +1058,7 @@ static int svm_check_nested_events(struct kvm_vcpu *vcpu)
 			return -EBUSY;
 		if (!nested_exit_on_smi(svm))
 			return 0;
-		nested_svm_smi(svm);
+		nested_svm_simple_vmexit(svm, SVM_EXIT_SMI);
 		return 0;
 	}
 
@@ -1111,7 +1067,7 @@ static int svm_check_nested_events(struct kvm_vcpu *vcpu)
 			return -EBUSY;
 		if (!nested_exit_on_nmi(svm))
 			return 0;
-		nested_svm_nmi(svm);
+		nested_svm_simple_vmexit(svm, SVM_EXIT_NMI);
 		return 0;
 	}
 
@@ -1120,7 +1076,8 @@ static int svm_check_nested_events(struct kvm_vcpu *vcpu)
 			return -EBUSY;
 		if (!nested_exit_on_intr(svm))
 			return 0;
-		nested_svm_intr(svm);
+		trace_kvm_nested_intr_vmexit(svm->vmcb->save.rip);
+		nested_svm_simple_vmexit(svm, SVM_EXIT_INTR);
 		return 0;
 	}
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 54610270f66a..9fe9076d4b8b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2203,12 +2203,8 @@ static int emulate_svm_instr(struct kvm_vcpu *vcpu, int opcode)
 	int ret;
 
 	if (is_guest_mode(vcpu)) {
-		svm->vmcb->control.exit_code = guest_mode_exit_codes[opcode];
-		svm->vmcb->control.exit_info_1 = 0;
-		svm->vmcb->control.exit_info_2 = 0;
-
 		/* Returns '1' or -errno on failure, '0' on success. */
-		ret = nested_svm_vmexit(svm);
+		ret = nested_svm_simple_vmexit(svm, guest_mode_exit_codes[opcode]);
 		if (ret)
 			return ret;
 		return 1;
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index fbbb26dd0f73..c4a433c66a33 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -444,6 +444,15 @@ int svm_allocate_nested(struct vcpu_svm *svm);
 int nested_svm_vmrun(struct kvm_vcpu *vcpu);
 void nested_svm_vmloadsave(struct vmcb *from_vmcb, struct vmcb *to_vmcb);
 int nested_svm_vmexit(struct vcpu_svm *svm);
+
+static inline int nested_svm_simple_vmexit(struct vcpu_svm *svm, u32 exit_code)
+{
+	svm->vmcb->control.exit_code   = exit_code;
+	svm->vmcb->control.exit_info_1 = 0;
+	svm->vmcb->control.exit_info_2 = 0;
+	return nested_svm_vmexit(svm);
+}
+
 int nested_svm_exit_handled(struct vcpu_svm *svm);
 int nested_svm_check_permissions(struct kvm_vcpu *vcpu);
 int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
-- 
2.30.1.766.gb4fecdf3b7-goog