[PATCH 4/5] KVM: x86: allow handle_exit_irqoff to return EXIT_FASTPATH_*

[Paolo Bonzini]

Let handle_exit_irqoff() pass what it did to vcpu_enter_guest() and/or
handle_exit().  This will be needed to trigger async page fault handling,
and to suppress reflection of APF #PF exceptions, once vcpu->arch
will no longer have a host_apf_flags field.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
 arch/x86/include/asm/kvm_host.h | 2 +-
 arch/x86/kvm/svm/svm.c          | 4 +++-
 arch/x86/kvm/vmx/main.c         | 6 ++++--
 arch/x86/kvm/x86.c              | 3 ++-
 4 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3f096a0f3387..93170c70a17c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1681,7 +1681,7 @@ struct kvm_x86_ops {
 			       struct x86_instruction_info *info,
 			       enum x86_intercept_stage stage,
 			       struct x86_exception *exception);
-	void (*handle_exit_irqoff)(struct kvm_vcpu *vcpu);
+	fastpath_t (*handle_exit_irqoff)(struct kvm_vcpu *vcpu);
 
 	void (*update_cpu_dirty_logging)(struct kvm_vcpu *vcpu, bool enable);
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e0ff458761cf..b720c1ff7134 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -5091,7 +5091,7 @@ static int svm_check_intercept(struct kvm_vcpu *vcpu,
 	return ret;
 }
 
-static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
+static fastpath_t svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 {
 	switch (to_svm(vcpu)->vmcb->control.exit_code) {
 	case SVM_EXIT_EXCP_BASE + MC_VECTOR:
@@ -5103,6 +5103,8 @@ static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 	default:
 		break;
 	}
+
+	return EXIT_FASTPATH_NONE;
 }
 
 static void svm_setup_mce(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index b46f8f60ce70..b742e2370dd6 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -941,10 +941,10 @@ static void handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu,
 	vcpu->arch.at_instruction_boundary = true;
 }
 
-static void vt_handle_exit_irqoff(struct kvm_vcpu *vcpu)
+static fastpath_t vt_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 {
 	if (to_vt(vcpu)->emulation_required)
-		return;
+		return EXIT_FASTPATH_NONE;
 
 	switch (vt_get_exit_reason(vcpu).basic) {
 	case EXIT_REASON_EXTERNAL_INTERRUPT:
@@ -959,6 +959,8 @@ static void vt_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 	default:
 		break;
 	}
+
+	return EXIT_FASTPATH_NONE;
 }
 
 static int vt_handle_exit(struct kvm_vcpu *vcpu,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 32563a91fba9..af8cdfd81180 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8504,7 +8504,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	if (vcpu->arch.xfd_no_write_intercept)
 		fpu_sync_guest_vmexit_xfd_state();
 
-	kvm_x86_call(handle_exit_irqoff)(vcpu);
+	if (exit_fastpath == EXIT_FASTPATH_NONE)
+		exit_fastpath = kvm_x86_call(handle_exit_irqoff)(vcpu);
 
 	if (vcpu->arch.guest_fpu.xfd_err)
 		wrmsrq(MSR_IA32_XFD_ERR, 0);
-- 
2.56.0