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mc146818rtc: fix timer interrupt reinjection again

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Commit 369b41359a broke timer interrupt
reinjection when there is no period change by the guest.  In that
case, old_period is 0, which ends up zeroing irq_coalesced (counter of
reinjected interrupts).

The consequence is Windows 7 is unable to synchronize time via NTP.
Easily reproducible by playing a fullscreen video with cirrus and VNC.

Fix by passing s->period when periodic_timer_update is called due to
expiration of the timer.  With this change, old_period == 0 only
means that the periodic timer was off.

Reported-by: Marcelo Tosatti <mtosatti@redhat.com>
Co-developed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2019-11-17 10:28:14 +01:00
parent 3ae32adff1
commit 7a3e29b12f
1 changed files with 9 additions and 7 deletions
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16
hw/rtc/mc146818rtc.c
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@ -168,12 +168,14 @@ static uint32_t rtc_periodic_clock_ticks(RTCState *s)
* is just due to period adjustment.
*/
static void
periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period)
periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period, bool period_change)
{
uint32_t period;
int64_t cur_clock, next_irq_clock, lost_clock = 0;
period = rtc_periodic_clock_ticks(s);
s->period = period;
if (!period) {
s->irq_coalesced = 0;
timer_del(s->periodic_timer);
@ -188,7 +190,7 @@ periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period)
* if the periodic timer's update is due to period re-configuration,
* we should count the clock since last interrupt.
*/
if (old_period) {
if (old_period && period_change) {
int64_t last_periodic_clock, next_periodic_clock;
next_periodic_clock = muldiv64(s->next_periodic_time,
@ -215,7 +217,6 @@ periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period)
if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) {
uint32_t old_irq_coalesced = s->irq_coalesced;
s->period = period;
lost_clock += old_irq_coalesced * old_period;
s->irq_coalesced = lost_clock / s->period;
lost_clock %= s->period;
@ -245,7 +246,7 @@ static void rtc_periodic_timer(void *opaque)
{
RTCState *s = opaque;
periodic_timer_update(s, s->next_periodic_time, 0);
periodic_timer_update(s, s->next_periodic_time, s->period, false);
s->cmos_data[RTC_REG_C] |= REG_C_PF;
if (s->cmos_data[RTC_REG_B] & REG_B_PIE) {
s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
@ -511,7 +512,7 @@ static void cmos_ioport_write(void *opaque, hwaddr addr,
if (update_periodic_timer) {
periodic_timer_update(s, qemu_clock_get_ns(rtc_clock),
old_period);
old_period, true);
}
check_update_timer(s);
@ -550,7 +551,7 @@ static void cmos_ioport_write(void *opaque, hwaddr addr,
if (update_periodic_timer) {
periodic_timer_update(s, qemu_clock_get_ns(rtc_clock),
old_period);
old_period, true);
}
check_update_timer(s);
@ -794,6 +795,7 @@ static int rtc_post_load(void *opaque, int version_id)
s->offset = 0;
check_update_timer(s);
}
s->period = rtc_periodic_clock_ticks(s);
/* The periodic timer is deterministic in record/replay mode,
* so there is no need to update it after loading the vmstate.
@ -803,7 +805,7 @@ static int rtc_post_load(void *opaque, int version_id)
uint64_t now = qemu_clock_get_ns(rtc_clock);
if (now < s->next_periodic_time ||
now > (s->next_periodic_time + get_max_clock_jump())) {
periodic_timer_update(s, qemu_clock_get_ns(rtc_clock), 0);
periodic_timer_update(s, qemu_clock_get_ns(rtc_clock), s->period, false);
}
}