kvm: x86: Track irq vectors in ioapic->rtc_status.dest_map

BugLink: http://bugs.launchpad.net/bugs/1649718

This allows backtracking later in case the rtc irq has been
moved to another vcpu/vector.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 9daa5007)
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

arch/x86/kvm/ioapic.h

@@ -41,7 +41,14 @@ struct kvm_vcpu;
 #endif
 
 struct dest_map {
+	/* vcpu bitmap where IRQ has been sent */
 	DECLARE_BITMAP(map, KVM_MAX_VCPUS);
+
+	/*
+	 * Vector sent to a given vcpu, only valid when
+	 * the vcpu's bit in map is set
+	 */
+	u8 vectors[KVM_MAX_VCPUS];
 };
 
 

arch/x86/kvm/lapic.c

@@ -839,8 +839,10 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
 
 		result = 1;
 
-		if (dest_map)
+		if (dest_map) {
 			__set_bit(vcpu->vcpu_id, dest_map->map);
+			dest_map->vectors[vcpu->vcpu_id] = vector;
+		}
 
 		if (apic_test_vector(vector, apic->regs + APIC_TMR) != !!trig_mode) {
 			if (trig_mode)