From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Egger Subject: Re: RTC patch Date: Wed, 22 Aug 2012 17:01:44 +0200 Message-ID: <5034F458.2090609@amd.com> References: <1345454240.28762.18.camel@zakaz.uk.xensource.com> <50323640020000780009662A@nat28.tlf.novell.com> <50338D02.8050009@amd.com> <5033B0070200007800096B4D@nat28.tlf.novell.com> <5034B907.7020506@amd.com> <50350D1F0200007800096F9C@nat28.tlf.novell Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <50350D1F0200007800096F9C@nat28.tlf.novell.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: Jan Beulich Cc: xen-devel List-Id: xen-devel@lists.xenproject.org On 08/22/12 16:47, Jan Beulich wrote: >>>> On 22.08.12 at 12:48, Christoph Egger wrote: >> On 08/21/12 15:57, Jan Beulich wrote: >> >>>>>> On 21.08.12 at 15:28, Christoph Egger wrote: >>>> On 08/20/12 13:06, Jan Beulich wrote: >>>> >>>>>>>> On 20.08.12 at 11:17, Ian Campbell wrote: >>>>>> * fix high change rate to CMOS RTC periodic interrupt causing >>>>>> guest wall clock time to lag (possible fix outlined, needs to be >>>>>> put in patch form and thoroughly reviewed/tested for unwanted >>>>>> side effects, Jan Beulich) >>>>> >>>>> Patch was posted, but no comments or approval to commit so far. >>>>> Also, reportedly the patch only improves the situation, it doesn't >>>>> completely eliminate the problem. For the moment I'm out of ideas, >>>>> though, and hence would hope some others could help here. >>>> >>>> >>>> Can you point me to the patch (or resend it to me), please? >>>> I have some trouble with getting XP Mode in Windows 7 (nested >>>> virtualization) booting and figured out it uses the RTC. >>>> I want to give this patch a try. >>> >>> http://lists.xen.org/archives/html/xen-devel/2012-08/msg01303.html >> >> When booting Windows 7 I get a crash due to a NULL pointer dereference >> in xen/common/spinlock.c:45. >> It looks like the spin lock is not initialized. > > I rather think NULL gets passed from pt_update_irq() to > rtc_periodic_interrupt(). Yet rtc.c's sole call to > create_periodic_time() clearly passes non-NULL. Oh, > hpet_set_timer() can pass a literal 8 (which I didn't spot > grepping for RTC_IRQ) - could you refine the check in > pt_update_irq() > > else if ( irq == RTC_IRQ ) > > to read > > else if ( irq == RTC_IRQ && pt_priv ) Yes, Windows 7 boots with this change. Christoph -- ---to satisfy European Law for business letters: Advanced Micro Devices GmbH Einsteinring 24, 85689 Dornach b. Muenchen Geschaeftsfuehrer: Alberto Bozzo Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632