KVM: Introduce kvm_vcpu_is_bsp() function.

Use it instead of open code "vcpu_id zero is BSP" assumption.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

virt/kvm/ioapic.c

diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 2a56671..0532fa6 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -164,7 +164,9 @@
 	/* Always delivery PIT interrupt to vcpu 0 */
 	if (irq == 0) {
 		irqe.dest_mode = 0; /* Physical mode. */
-		irqe.dest_id = ioapic->kvm->vcpus[0]->vcpu_id;
+		/* need to read apic_id from apic regiest since
+		 * it can be rewritten */
+		irqe.dest_id = ioapic->kvm->bsp_vcpu->vcpu_id;
 	}
 #endif
 	return kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe);