kvm: lapic: Introduce APICv update helper function

Re-factor code into a helper function for setting lapic parameters when
activate/deactivate APICv, and export the function for subsequent usage.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/lapic.c

@@ -2187,6 +2187,21 @@ void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value)
 		pr_warn_once("APIC base relocation is unsupported by KVM");
 }
 
+void kvm_apic_update_apicv(struct kvm_vcpu *vcpu)
+{
+	struct kvm_lapic *apic = vcpu->arch.apic;
+
+	if (vcpu->arch.apicv_active) {
+		/* irr_pending is always true when apicv is activated. */
+		apic->irr_pending = true;
+		apic->isr_count = 1;
+	} else {
+		apic->irr_pending = (apic_search_irr(apic) != -1);
+		apic->isr_count = count_vectors(apic->regs + APIC_ISR);
+	}
+}
+EXPORT_SYMBOL_GPL(kvm_apic_update_apicv);
+
 void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
@@ -2229,8 +2244,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 		kvm_lapic_set_reg(apic, APIC_ISR + 0x10 * i, 0);
 		kvm_lapic_set_reg(apic, APIC_TMR + 0x10 * i, 0);
 	}
-	apic->irr_pending = vcpu->arch.apicv_active;
-	apic->isr_count = vcpu->arch.apicv_active ? 1 : 0;
+	kvm_apic_update_apicv(vcpu);
 	apic->highest_isr_cache = -1;
 	update_divide_count(apic);
 	atomic_set(&apic->lapic_timer.pending, 0);
@@ -2487,9 +2501,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
 	apic_manage_nmi_watchdog(apic, kvm_lapic_get_reg(apic, APIC_LVT0));
 	update_divide_count(apic);
 	start_apic_timer(apic);
-	apic->irr_pending = true;
-	apic->isr_count = vcpu->arch.apicv_active ?
-				1 : count_vectors(apic->regs + APIC_ISR);
+	kvm_apic_update_apicv(vcpu);
 	apic->highest_isr_cache = -1;
 	if (vcpu->arch.apicv_active) {
 		kvm_x86_ops->apicv_post_state_restore(vcpu);

arch/x86/kvm/lapic.h

@@ -91,6 +91,7 @@ void kvm_apic_update_ppr(struct kvm_vcpu *vcpu);
 int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq,
 		     struct dest_map *dest_map);
 int kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type);
+void kvm_apic_update_apicv(struct kvm_vcpu *vcpu);
 
 bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
 		struct kvm_lapic_irq *irq, int *r, struct dest_map *dest_map);