From 224a226b03d2c0503915bd1c1139b37b56afd62d Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Wed, 4 Dec 2019 15:21:09 +0100 Subject: [PATCH 3/3] mc146818rtc: fix timer interrupt reinjection again RH-Author: Marcelo Tosatti Message-id: <20191204152436.823942711@amt.cnet> Patchwork-id: 92887 O-Subject: [RHEL-7.8 qemu-kvm-rhev PATCH 3/3] mc146818rtc: fix timer interrupt reinjection again Bugzilla: 1639098 RH-Acked-by: Laszlo Ersek RH-Acked-by: Paolo Bonzini RH-Acked-by: Vitaly Kuznetsov BZ: 1639098 Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=24854309 BRANCH: rhv7/master-2.12.0 Upstream: 7a3e29b12f5afe0106a5713bb4db6e23dc66ef91 of pbonzini's for-upstream tree. Commit 369b41359af46bded5799c9ef8be2b641d92e043 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 Co-developed-by: Marcelo Tosatti Signed-off-by: Paolo Bonzini Signed-off-by: Miroslav Rezanina --- hw/timer/mc146818rtc.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c index d848911..7459040 100644 --- a/hw/timer/mc146818rtc.c +++ b/hw/timer/mc146818rtc.c @@ -190,12 +190,14 @@ 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); @@ -210,7 +212,7 @@ 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, @@ -237,7 +239,6 @@ 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; @@ -267,7 +268,7 @@ 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; @@ -533,7 +534,7 @@ 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); @@ -572,7 +573,7 @@ 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); @@ -816,6 +817,7 @@ 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. @@ -825,7 +827,7 @@ 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); } } @@ -893,7 +895,7 @@ static void rtc_notify_clock_reset(Notifier *notifier, void *data) int64_t now = *(int64_t *)data; rtc_set_date_from_host(ISA_DEVICE(s)); - periodic_timer_update(s, now, 0); + periodic_timer_update(s, now, s->period, false); check_update_timer(s); if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) { -- 1.8.3.1