KVM: x86: Check for in-kernel xAPIC when querying APICv for directed yield

Use kvm_vcpu_apicv_active() to check if APICv is active when seeing if a
vCPU is a candidate for directed yield due to a pending ACPIv interrupt.
This will allow moving apicv_active into kvm_lapic without introducing a
potential NULL pointer deref (kvm_vcpu_apicv_active() effectively adds a
pre-check on the vCPU having an in-kernel APIC).

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220614230548.3852141-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -12395,7 +12395,8 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
 
 bool kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu)
 {
-	if (vcpu->arch.apicv_active && static_call(kvm_x86_dy_apicv_has_pending_interrupt)(vcpu))
+	if (kvm_vcpu_apicv_active(vcpu) &&
+	    static_call(kvm_x86_dy_apicv_has_pending_interrupt)(vcpu))
 		return true;
 
 	return false;