@@ -344,6 +344,21 @@ static void rtc_calibrate_time(RTCState *s)
s->current_tm = *ret;
}
+static int update_in_progress(RTCState *s)
+{
+ int64_t guest_usec;
+
+ if (s->cmos_data[RTC_REG_B] & REG_B_SET) {
+ return 0;
+ }
+ guest_usec = get_guest_rtc_us(s);
+ /* UIP bit will be set at last 244us of every second. */
+ if ((guest_usec % USEC_PER_SEC) >= (USEC_PER_SEC - 244)) {
+ return 1;
+ }
+ return 0;
+}
+
static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
{
RTCState *s = opaque;
@@ -369,6 +384,9 @@ static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
break;
case RTC_REG_A:
ret = s->cmos_data[s->cmos_index];
+ if (update_in_progress(s)) {
+ ret |= REG_A_UIP;
+ }
break;
case RTC_REG_C:
ret = s->cmos_data[s->cmos_index];
The UIP will be set when updating cycle begins and cleared after updated cycle ended. Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com> --- hw/mc146818rtc.c | 18 ++++++++++++++++++ 1 files changed, 18 insertions(+), 0 deletions(-) -- 1.7.1