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replay: don't use rtc clock on loadvm phase 

This patch disables the update of the periodic timer of mc146818rtc
in record/replay mode. State of this timer is saved and therefore does
not need to be updated in record/replay mode.
Read of RTC breaks the replay because all rtc reads have to be the same
as in record mode.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20170124071730.4572.41874.stgit@PASHA-ISP>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Pavel Dovgalyuk 2017-01-24 10:17:30 +03:00 committed by Paolo Bonzini
parent d718b14b8c
commit 1dfb1b2d34
1 changed files with 11 additions and 4 deletions
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7
hw/timer/mc146818rtc.c
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@ -27,6 +27,7 @@
#include "hw/hw.h" #include "hw/hw.h"
#include "qemu/timer.h" #include "qemu/timer.h"
#include "sysemu/sysemu.h" #include "sysemu/sysemu.h"
#include "sysemu/replay.h"
#include "hw/timer/mc146818rtc.h" #include "hw/timer/mc146818rtc.h"
#include "qapi/visitor.h" #include "qapi/visitor.h"
#include "qapi-event.h" #include "qapi-event.h"
@ -734,11 +735,17 @@ static int rtc_post_load(void *opaque, int version_id)
check_update_timer(s); check_update_timer(s);
} }
/* The periodic timer is deterministic in record/replay mode,
* so there is no need to update it after loading the vmstate.
* Reading RTC here would misalign record and replay.
*/
if (replay_mode == REPLAY_MODE_NONE) {
uint64_t now = qemu_clock_get_ns(rtc_clock); uint64_t now = qemu_clock_get_ns(rtc_clock);
if (now < s->next_periodic_time || if (now < s->next_periodic_time ||
now > (s->next_periodic_time + get_max_clock_jump())) { now > (s->next_periodic_time + get_max_clock_jump())) {
periodic_timer_update(s, qemu_clock_get_ns(rtc_clock)); periodic_timer_update(s, qemu_clock_get_ns(rtc_clock));
} }
}
#ifdef TARGET_I386 #ifdef TARGET_I386
if (version_id >= 2) { if (version_id >= 2) {