From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751790Ab3E1SWy (ORCPT ); Tue, 28 May 2013 14:22:54 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:51454 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750998Ab3E1SWw (ORCPT ); Tue, 28 May 2013 14:22:52 -0400 X-IronPort-AV: E=Sophos;i="4.87,759,1363132800"; d="scan'208";a="26485989" From: David Vrabel To: CC: David Vrabel , Konrad Rzeszutek Wilk , John Stultz , Subject: [PATCHv2 0/2] xen: maintain an accurate persistent clock in more cases Date: Tue, 28 May 2013 19:22:46 +0100 Message-ID: <1369765368-10823-1-git-send-email-david.vrabel@citrix.com> X-Mailer: git-send-email 1.7.2.5 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The kernel has limited support for updating the persistent clock or RTC when NTP is synced. This has the following limitations: * The persistent clock is not updated on step changes. This leaves a window where it will be incorrect (while NTP resyncs). * Xen guests use the Xen wallclock as their persistent clock. dom0 maintains this clock so it is persistent for domUs and not dom0 itself. These series fixes the above limitations and depends on "x86: increase precision of x86_platform.get/set_wallclock()" which was previously posted. Changes since v1: Reworked to use the pvclock_gtod notifier to sync the wallclock (this looked similar to what a KVM host does). update_persistent_clock() will now only update the CMOS RTC. David [1] http://lists.xen.org/archives/html/xen-devel/2013-05/msg01402.html