From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Stultz Subject: Re: [PATCH 3/3] x86/xen: sync the CMOS RTC as well as the Xen wallclock Date: Tue, 14 May 2013 10:24:09 -0700 Message-ID: <51927339.5070402__33189.0001580634$1368552382$gmane$org@linaro.org> References: <1368467768-2316-1-git-send-email-david.vrabel@citrix.com> <1368467768-2316-4-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1368467768-2316-4-git-send-email-david.vrabel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: David Vrabel Cc: Thomas Gleixner , Konrad Rzeszutek Wilk , linux-kernel@vger.kernel.org, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 05/13/2013 10:56 AM, David Vrabel wrote: > From: David Vrabel > > If NTP is used in dom0 and it is synchronized to its clock source, > then the kernel will periodically synchronize the Xen wallclock with > the system time. Updates to the Xen wallclock do not persist across > reboots, so also synchronize the CMOS RTC (as on bare metal). > > Signed-off-by: David Vrabel > --- > arch/x86/xen/time.c | 11 ++++++++++- > 1 files changed, 10 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c > index a1947ac..4656165 100644 > --- a/arch/x86/xen/time.c > +++ b/arch/x86/xen/time.c > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -199,17 +200,25 @@ static void xen_get_wallclock(struct timespec *now) > static int xen_set_wallclock(const struct timespec *now) > { > struct xen_platform_op op; > + int ret; > > /* do nothing for domU */ > if (!xen_initial_domain()) > return -1; > > + /* Set the Xen wallclock. */ > op.cmd = XENPF_settime; > op.u.settime.secs = now->tv_sec; > op.u.settime.nsecs = now->tv_nsec; > op.u.settime.system_time = xen_clocksource_read(); > > - return HYPERVISOR_dom0_op(&op); > + ret = HYPERVISOR_dom0_op(&op); > + if (ret) > + return ret; > + > + /* Set the hardware RTC. */ > + return mach_set_rtc_mmss(now); Sorry, just noticed one more thing while applying this. Do all Xen systems run on hardware that has the conventional CMOS clock? What happens if the bare-metal needs to use efi_set_rtc() or vrtc_set_mmss() ? thanks -john