apic: add function to apic that will be used by hvf

This patch adds the function apic_get_highest_priority_irr to
apic.c and exports it through the interface in apic.h for use by hvf.

Signed-off-by: Sergio Andres Gomez Del Real <Sergio.G.DelReal@gmail.com>
Message-Id: <20170913090522.4022-8-Sergio.G.DelReal@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/intc/apic.c

@@ -305,6 +305,18 @@ static void apic_set_tpr(APICCommonState *s, uint8_t val)
     }
 }
 
+int apic_get_highest_priority_irr(DeviceState *dev)
+{
+    APICCommonState *s;
+
+    if (!dev) {
+        /* no interrupts */
+        return -1;
+    }
+    s = APIC_COMMON(dev);
+    return get_highest_priority_int(s->irr);
+}
+
 static uint8_t apic_get_tpr(APICCommonState *s)
 {
     apic_sync_vapic(s, SYNC_FROM_VAPIC);

include/hw/i386/apic.h

@@ -20,6 +20,7 @@ void apic_init_reset(DeviceState *s);
 void apic_sipi(DeviceState *s);
 void apic_poll_irq(DeviceState *d);
 void apic_designate_bsp(DeviceState *d, bool bsp);
+int apic_get_highest_priority_irr(DeviceState *dev);
 
 /* pc.c */
 DeviceState *cpu_get_current_apic(void);