From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752627Ab3ENQPA (ORCPT ); Tue, 14 May 2013 12:15:00 -0400 Received: from nat28.tlf.novell.com ([130.57.49.28]:54110 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751103Ab3ENQO7 convert rfc822-to-8bit (ORCPT ); Tue, 14 May 2013 12:14:59 -0400 Message-Id: <51927F2002000078000D6224@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.2 Date: Tue, 14 May 2013 17:14:56 +0100 From: "Jan Beulich" To: "John Stultz" Cc: "David Vrabel" , "Jeremy Fitzhardinge" , "Thomas Gleixner" , , "Konrad Rzeszutek Wilk" , Subject: Re: [Xen-devel] [PATCH 3/3] x86/xen: sync the CMOS RTC as well as the Xen wallclock References: <1368467768-2316-1-git-send-email-david.vrabel@citrix.com> <1368467768-2316-4-git-send-email-david.vrabel@citrix.com> <51918ABB.5030501@linaro.org> <51920A9502000078000D5D84@nat28.tlf.novell.com> <51925F70.5000309@linaro.org> In-Reply-To: <51925F70.5000309@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> On 14.05.13 at 17:59, John Stultz wrote: > On 05/14/2013 12:57 AM, Jan Beulich wrote: >>>>> On 14.05.13 at 02:52, John Stultz wrote: >>> Honestly, it seems a little strange to me. If you're running as dom0, >>> why does HYPERVISOR_dom0_op() not cause the hypervisor to set the cmos >>> its virtualizing? This seems to mess with the proper virtualization >>> layering. >> Thy hypervisor tries to control as little system and peripheral devices >> as possible, and the CMOS (including the clock) is among those not >> controlled by it, but by Dom0. > > Huh. So what does calling HYPERVISOR_dom0_op do then? Here it merely tells the hypervisor that the wall clock changed (so it can propagate this on to DomU-s). Jan