From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35267) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cVvMA-0006HY-04 for qemu-devel@nongnu.org; Tue, 24 Jan 2017 02:17:32 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cVvM9-0005tV-0q for qemu-devel@nongnu.org; Tue, 24 Jan 2017 02:17:29 -0500 Received: from mail.ispras.ru ([83.149.199.45]:38592) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cVvM8-0005t5-QA for qemu-devel@nongnu.org; Tue, 24 Jan 2017 02:17:28 -0500 From: Pavel Dovgalyuk Date: Tue, 24 Jan 2017 10:17:30 +0300 Message-ID: <20170124071730.4572.41874.stgit@PASHA-ISP> In-Reply-To: <20170124071654.4572.41407.stgit@PASHA-ISP> References: <20170124071654.4572.41407.stgit@PASHA-ISP> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] [PATCH v7 06/14] replay: don't use rtc clock on loadvm phase List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, mst@redhat.com, jasowang@redhat.com, quintela@redhat.com, dovgaluk@ispras.ru, kraxel@redhat.com, pbonzini@redhat.com 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 --- hw/timer/mc146818rtc.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c index da209d0..5638777 100644 --- a/hw/timer/mc146818rtc.c +++ b/hw/timer/mc146818rtc.c @@ -27,6 +27,7 @@ #include "hw/hw.h" #include "qemu/timer.h" #include "sysemu/sysemu.h" +#include "sysemu/replay.h" #include "hw/timer/mc146818rtc.h" #include "qapi/visitor.h" #include "qapi-event.h" @@ -734,10 +735,15 @@ static int rtc_post_load(void *opaque, int version_id) check_update_timer(s); } - 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)); + /* Periodic timer is deterministic in record/replay mode. + No need to update it after loading the vmstate. + Reading RTC here may break the execution. */ + if (replay_mode == REPLAY_MODE_NONE) { + 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)); + } } #ifdef TARGET_I386