rtc: clear non-PF bits when reinjecting on ack

When an rtc interrupt is reinjected immediately after being acked,
other interrupts should not be reinjected, so do clear their bits.

Also, if the periodic interrupts have been disabled before acking,
do not reinject, as the guest might get very confused!

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

hw/mc146818rtc.c

@@ -477,10 +477,13 @@ static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
         case RTC_REG_C:
             ret = s->cmos_data[s->cmos_index];
             qemu_irq_lower(s->irq);
+            s->cmos_data[RTC_REG_C] = 0x00;
 #ifdef TARGET_I386
             if(s->irq_coalesced &&
+                    (s->cmos_data[RTC_REG_B] & REG_B_PIE) &&
                     s->irq_reinject_on_ack_count < RTC_REINJECT_ON_ACK_COUNT) {
                 s->irq_reinject_on_ack_count++;
+                s->cmos_data[RTC_REG_C] |= REG_C_IRQF | REG_C_PF;
                 apic_reset_irq_delivered();
                 DPRINTF_C("cmos: injecting on ack\n");
                 qemu_irq_raise(s->irq);
@@ -489,11 +492,8 @@ static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
                     DPRINTF_C("cmos: coalesced irqs decreased to %d\n",
                               s->irq_coalesced);
                 }
-                break;
             }
 #endif
-
-            s->cmos_data[RTC_REG_C] = 0x00;
             break;
         default:
             ret = s->cmos_data[s->cmos_index];