From: "Zhang, Yang Z" <yang.z.zh...@intel.com>
If an interrupt flag is already set when the interrupt becomes enabled,
raise an interrupt immediately, and vice versa if interrupts become
disabled.
Signed-off-by: Yang Zhang <yang.z.zh...@intel.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
hw/mc146818rtc.c | 9 +++++++++
hw/mc146818rtc_regs.h | 1 +
2 files changed, 10 insertions(+)
diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
index 6a7dcb8..46f0c10 100644
--- a/hw/mc146818rtc.c
+++ b/hw/mc146818rtc.c
@@ -220,6 +220,15 @@ static void cmos_ioport_write(void *opaque, uint32_t addr,
uint32_t data)
rtc_set_time(s);
}
}
+ /* if an interrupt flag is already set when the interrupt
+ * becomes enabled, raise an interrupt immediately. */
+ if (data & s->cmos_data[RTC_REG_C] & REG_C_MASK) {
+ s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
+ qemu_irq_raise(s->irq);
+ } else {
+ s->cmos_data[RTC_REG_C] &= ~REG_C_IRQF;
+ qemu_irq_lower(s->irq);
+ }
s->cmos_data[RTC_REG_B] = data;
periodic_timer_update(s, qemu_get_clock_ns(rtc_clock));
break;
diff --git a/hw/mc146818rtc_regs.h b/hw/mc146818rtc_regs.h
index 3ab3770..fc10076 100644
--- a/hw/mc146818rtc_regs.h
+++ b/hw/mc146818rtc_regs.h
@@ -58,5 +58,6 @@
#define REG_C_IRQF 0x80
#define REG_C_PF 0x40
#define REG_C_AF 0x20
+#define REG_C_MASK 0x70
#endif
--
1.7.10.2
