From 8af16b9722f5bdeacf3a30c21490846e24b989b2 Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Wed, 4 Dec 2019 15:21:08 +0100
Subject: [PATCH 2/3] Revert "mc146818rtc: fix timer interrupt reinjection"
RH-Author: Marcelo Tosatti <mtosatti@redhat.com>
Message-id: <20191204152436.753293175@amt.cnet>
Patchwork-id: 92888
O-Subject: [RHEL-7.8 qemu-kvm-rhev PATCH 2/3] Revert "mc146818rtc: fix timer interrupt reinjection"
Bugzilla: 1639098
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>
BZ: 1639098
Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=24854309
BRANCH: rhv7/master-2.12.0
Upstream: 3ae32adff17226bc6a5f3fd7bb9804e6779e0660
of pbonzini's for-upstream tree.
This reverts commit b429de730174b388ea5760e3debb0d542ea3c261, except
that the reversal of the outer "if (period)" is left in.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
hw/timer/mc146818rtc.c | 67 +++++++++++++++++++++++++-------------------------
1 file changed, 33 insertions(+), 34 deletions(-)
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index 296d974..d848911 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -196,7 +196,6 @@ periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period)
int64_t cur_clock, next_irq_clock, lost_clock = 0;
period = rtc_periodic_clock_ticks(s);
-
if (!period) {
s->irq_coalesced = 0;
timer_del(s->periodic_timer);
@@ -219,42 +218,42 @@ periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period)
last_periodic_clock = next_periodic_clock - old_period;
lost_clock = cur_clock - last_periodic_clock;
assert(lost_clock >= 0);
+ }
+ /*
+ * s->irq_coalesced can change for two reasons:
+ *
+ * a) if one or more periodic timer interrupts have been lost,
+ * lost_clock will be more that a period.
+ *
+ * b) when the period may be reconfigured, we expect the OS to
+ * treat delayed tick as the new period. So, when switching
+ * from a shorter to a longer period, scale down the missing,
+ * because the OS will treat past delayed ticks as longer
+ * (leftovers are put back into lost_clock). When switching
+ * to a shorter period, scale up the missing ticks since the
+ * OS handler will treat past delayed ticks as shorter.
+ */
+ 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;
+ if (old_irq_coalesced != s->irq_coalesced ||
+ old_period != s->period) {
+ DPRINTF_C("cmos: coalesced irqs scaled from %d to %d, "
+ "period scaled from %d to %d\n", old_irq_coalesced,
+ s->irq_coalesced, old_period, s->period);
+ rtc_coalesced_timer_update(s);
+ }
+ } else {
/*
- * s->irq_coalesced can change for two reasons:
- *
- * a) if one or more periodic timer interrupts have been lost,
- * lost_clock will be more that a period.
- *
- * b) when the period may be reconfigured, we expect the OS to
- * treat delayed tick as the new period. So, when switching
- * from a shorter to a longer period, scale down the missing,
- * because the OS will treat past delayed ticks as longer
- * (leftovers are put back into lost_clock). When switching
- * to a shorter period, scale up the missing ticks since the
- * OS handler will treat past delayed ticks as shorter.
+ * no way to compensate the interrupt if LOST_TICK_POLICY_SLEW
+ * is not used, we should make the time progress anyway.
*/
- 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;
- if (old_irq_coalesced != s->irq_coalesced ||
- old_period != s->period) {
- DPRINTF_C("cmos: coalesced irqs scaled from %d to %d, "
- "period scaled from %d to %d\n", old_irq_coalesced,
- s->irq_coalesced, old_period, s->period);
- rtc_coalesced_timer_update(s);
- }
- } else {
- /*
- * no way to compensate the interrupt if LOST_TICK_POLICY_SLEW
- * is not used, we should make the time progress anyway.
- */
- lost_clock = MIN(lost_clock, period);
- }
+ lost_clock = MIN(lost_clock, period);
}
assert(lost_clock >= 0 && lost_clock <= period);
--
1.8.3.1