From nobody Tue Oct 22 23:22:38 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=163.com ARC-Seal: i=1; a=rsa-sha256; t=1728959117; cv=none; d=zohomail.com; s=zohoarc; b=P2hFSwLh4M5s0cvjQfb5BBE9dsms5sFPVNwP7yP/lAQmfEvgr9Y0+K+0sbg7OqG8zQvffksgTEOmzYdkLh9D1Upug1XbJ4J5nb+/NzKneb3+4Re8vnszwFkss5kYeBWNiHW9Zvl/GXGHKNaJR5gf1tukYtipeX6ugI/tUYfRxOI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1728959117; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=lM0mqD37BD1KHWcxASFEHk9BlsaaSV3648O9jeiqdaI=; b=Jh1uiKq8wHhfUsUmz8g9Dcjc6XtuGcqzt1PB/Mch2R0BtUt/Cs7x4pYBLV2Zw/l2my23xhtDPDbLGya/VJ3lxdMIPBKP1+IReEUuIvwF7GG6u1z8fdAiAv/AcH5DiBnX/eACdNk6/m6yjmPg1Nz/Tm0JaDnqM+//rMVXTfSoFrs= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1728959117602624.9334469890218; Mon, 14 Oct 2024 19:25:17 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t0XEk-0007Vx-TY; Mon, 14 Oct 2024 22:24:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1t0XEh-0007Vk-N4 for qemu-devel@nongnu.org; Mon, 14 Oct 2024 22:24:35 -0400 Received: from m16.mail.163.com ([220.197.31.4]) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t0XEf-0000bH-7R for qemu-devel@nongnu.org; Mon, 14 Oct 2024 22:24:35 -0400 Received: from jshen28-imini-Pro.. (unknown [113.128.83.231]) by gzga-smtp-mtada-g0-2 (Coremail) with SMTP id _____wAntKZS0g1nFB1+BA--.51697S2; Tue, 15 Oct 2024 10:24:18 +0800 (CST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-ID:MIME-Version; bh=lM0mq D37BD1KHWcxASFEHk9BlsaaSV3648O9jeiqdaI=; b=J1uaEK+jmewDFNEYG9IvL FQTGLTE7OEGfQq/7Ul2W079VtjjowxPPKAblr9yYIRHaFkDSKdruxdN6H5koPiCa 1R72jbTUY9vNiIwl4XsTPoUdkVoLi0Ku/YaZz+6OvuI9I3xAQvaG6sa8HIidnfbN p2XC+L/pu4NZmr4BE9Gq7Q= From: shenjiatong To: qemu-devel@nongnu.org Cc: shenjiatong Subject: [PATCH] Fix negative lost clock causing VM crash Date: Tue, 15 Oct 2024 10:24:09 +0800 Message-ID: <20241015022416.804072-1-yshxxsjt715@163.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wAntKZS0g1nFB1+BA--.51697S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7WrW8ur13Jryfuw47Xw1DZFb_yoW8ZF4rp3 92kr9agwn2vF48Wrn7KFnrGrn8G3Z5C347tryUAw4ak3Wjqr48KFsxJryUKayq9FyrC3yU Za4Yqan8JF1jvw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0p_JPi8UUUUU= X-Originating-IP: [113.128.83.231] X-CM-SenderInfo: h1vk555vmwliqv6rljoofrz/1tbiMRJ5L2cNzFjJjQAAsP Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=220.197.31.4; envelope-from=yshxxsjt715@163.com; helo=m16.mail.163.com X-Spam_score_int: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @163.com) X-ZM-MESSAGEID: 1728959118509116600 Content-Type: text/plain; charset="utf-8" Under situation where virtual machine is running in a deployment where the system time is unstable, there is a chance that legacy OpenStack Windows machines without stimer enabled will crash if system time moves backwards and diftfix=3Dslew is enabled. This primarily caused by the fact the system time moves faster than NTP server and after synchronization, system time flows backwards. Signed-off-by: shenjiatong --- hw/rtc/mc146818rtc.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/hw/rtc/mc146818rtc.c b/hw/rtc/mc146818rtc.c index 8ccee9a385..fa5d7915b1 100644 --- a/hw/rtc/mc146818rtc.c +++ b/hw/rtc/mc146818rtc.c @@ -180,7 +180,6 @@ static void periodic_timer_update(MC146818RtcState *s, = int64_t current_time, RTC_CLOCK_RATE, NANOSECONDS_PER_SECOND); last_periodic_clock =3D next_periodic_clock - old_period; lost_clock =3D cur_clock - last_periodic_clock; - assert(lost_clock >=3D 0); } =20 /* @@ -199,10 +198,15 @@ static void periodic_timer_update(MC146818RtcState *s= , int64_t current_time, */ if (s->lost_tick_policy =3D=3D LOST_TICK_POLICY_SLEW) { uint32_t old_irq_coalesced =3D s->irq_coalesced; + if (lost_clock >=3D 0) { + lost_clock +=3D old_irq_coalesced * old_period; + s->irq_coalesced =3D lost_clock / s->period; + lost_clock %=3D s->period; + } else { + s->irq_coalesced =3D 0; + lost_clock =3D 0; + } =20 - lost_clock +=3D old_irq_coalesced * old_period; - s->irq_coalesced =3D lost_clock / s->period; - lost_clock %=3D s->period; if (old_irq_coalesced !=3D s->irq_coalesced || old_period !=3D s->period) { DPRINTF_C("cmos: coalesced irqs scaled from %d to %d, " @@ -215,6 +219,7 @@ static void periodic_timer_update(MC146818RtcState *s, = int64_t current_time, * no way to compensate the interrupt if LOST_TICK_POLICY_SLEW * is not used, we should make the time progress anyway. */ + lost_clock =3D MAX(0, lost_clock); lost_clock =3D MIN(lost_clock, period); } =20 --=20 2.43.0