KVM: x86: Optimization: Create SVM stubs for sync_pir_to_irr()

sync_pir_to_irr() is only called if vcpu->arch.apicv_active()==true.
In case it is false, VMX code make sure to set sync_pir_to_irr
to NULL.

Therefore, having SVM stubs allows to remove check for if
sync_pir_to_irr != NULL from all calling sites.

Signed-off-by: Liran Alon <liran.alon@oracle.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
[Return highest IRR in the SVM case. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

arch/x86/kvm/lapic.c

@@ -581,7 +581,7 @@ static void pv_eoi_clr_pending(struct kvm_vcpu *vcpu)
 static int apic_has_interrupt_for_ppr(struct kvm_lapic *apic, u32 ppr)
 {
 	int highest_irr;
-	if (kvm_x86_ops->sync_pir_to_irr && apic->vcpu->arch.apicv_active)
+	if (apic->vcpu->arch.apicv_active)
 		highest_irr = kvm_x86_ops->sync_pir_to_irr(apic->vcpu);
 	else
 		highest_irr = apic_find_highest_irr(apic);

arch/x86/kvm/svm.c

@@ -6740,6 +6740,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 	.load_eoi_exitmap = svm_load_eoi_exitmap,
 	.hwapic_irr_update = svm_hwapic_irr_update,
 	.hwapic_isr_update = svm_hwapic_isr_update,
+	.sync_pir_to_irr = kvm_lapic_find_highest_irr,
 	.apicv_post_state_restore = avic_post_state_restore,
 
 	.set_tss_addr = svm_set_tss_addr,

arch/x86/kvm/x86.c

@@ -2973,7 +2973,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
 				    struct kvm_lapic_state *s)
 {
-	if (kvm_x86_ops->sync_pir_to_irr && vcpu->arch.apicv_active)
+	if (vcpu->arch.apicv_active)
 		kvm_x86_ops->sync_pir_to_irr(vcpu);
 
 	return kvm_apic_get_state(vcpu, s);
@@ -6820,7 +6820,7 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
 	if (irqchip_split(vcpu->kvm))
 		kvm_scan_ioapic_routes(vcpu, vcpu->arch.ioapic_handled_vectors);
 	else {
-		if (kvm_x86_ops->sync_pir_to_irr && vcpu->arch.apicv_active)
+		if (vcpu->arch.apicv_active)
 			kvm_x86_ops->sync_pir_to_irr(vcpu);
 		kvm_ioapic_scan_entry(vcpu, vcpu->arch.ioapic_handled_vectors);
 	}
@@ -7046,10 +7046,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	 * This handles the case where a posted interrupt was
 	 * notified with kvm_vcpu_kick.
 	 */
-	if (kvm_lapic_enabled(vcpu)) {
-		if (kvm_x86_ops->sync_pir_to_irr && vcpu->arch.apicv_active)
-			kvm_x86_ops->sync_pir_to_irr(vcpu);
-	}
+	if (kvm_lapic_enabled(vcpu) && vcpu->arch.apicv_active)
+		kvm_x86_ops->sync_pir_to_irr(vcpu);
 
 	if (vcpu->mode == EXITING_GUEST_MODE || kvm_request_pending(vcpu)
 	    || need_resched() || signal_pending(current)) {