KVM: x86: Introduce helper to check if auto-EOI is set in Hyper-V SynIC

As a preparation to making Hyper-V emulation optional, create a dedicated
kvm_hv_synic_auto_eoi_set() helper to avoid extra ifdefs in lapic.c

No functional change intended.
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Tested-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20231205103630.1391318-5-vkuznets@redhat.comSigned-off-by: Sean Christopherson <seanjc@google.com>

arch/x86/kvm/hyperv.h

@@ -105,6 +105,12 @@ int kvm_hv_synic_set_irq(struct kvm *kvm, u32 vcpu_id, u32 sint);
 void kvm_hv_synic_send_eoi(struct kvm_vcpu *vcpu, int vector);
 int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool dont_zero_synic_pages);
 
+static inline bool kvm_hv_synic_auto_eoi_set(struct kvm_vcpu *vcpu, int vector)
+{
+	return to_hv_vcpu(vcpu) &&
+	       test_bit(vector, to_hv_synic(vcpu)->auto_eoi_bitmap);
+}
+
 void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu);
 
 bool kvm_hv_assist_page_enabled(struct kvm_vcpu *vcpu);

arch/x86/kvm/lapic.c

@@ -2905,7 +2905,7 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
 	 */
 
 	apic_clear_irr(vector, apic);
-	if (to_hv_vcpu(vcpu) && test_bit(vector, to_hv_synic(vcpu)->auto_eoi_bitmap)) {
+	if (kvm_hv_synic_auto_eoi_set(vcpu, vector)) {
 		/*
 		 * For auto-EOI interrupts, there might be another pending
 		 * interrupt above PPR, so check whether to raise another