Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757517Ab0KVUQq (ORCPT ); Mon, 22 Nov 2010 15:16:46 -0500 Received: from claw.goop.org ([74.207.240.146]:44285 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753487Ab0KVUQp (ORCPT ); Mon, 22 Nov 2010 15:16:45 -0500 Message-ID: <4CEACFAB.90503@goop.org> Date: Mon, 22 Nov 2010 12:16:43 -0800 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.12) Gecko/20101027 Fedora/3.1.6-1.fc13 Lightning/1.0b3pre Thunderbird/3.1.6 MIME-Version: 1.0 To: "H. Peter Anvin" CC: "Xen-devel@lists.xensource.com" , kvm-devel , Glauber Costa , the arch/x86 maintainers , Linux Kernel Mailing List , Linux Virtualization , Olivier Hanesse , Avi Kivity , Eelco Dolstra Subject: Re: [PATCH] x86/pvclock-xen: zero last_value on resume References: <4CC708DE.1070000@goop.org> In-Reply-To: <4CC708DE.1070000@goop.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2555 Lines: 75 On 10/26/2010 09:59 AM, Jeremy Fitzhardinge wrote: > > If the guest domain has been suspend/resumed or migrated, then the > system clock backing the pvclock clocksource may revert to a smaller > value (ie, can be non-monotonic across the migration/save-restore). > Make sure we zero last_value in that case so that the domain > continues to see clock updates. Ping? Looks like this fell through the gaps. J > [ I don't know if kvm needs an analogous fix or not. ] > > Signed-off-by: Jeremy Fitzhardinge > Cc: Stable Kernel > Reported-by: Eelco Dolstra > Reported-by: Olivier Hanesse > Bisected-by: Cédric Schieli > Tested-by: Cédric Schieli > > diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h > index cd02f32..6226870 100644 > --- a/arch/x86/include/asm/pvclock.h > +++ b/arch/x86/include/asm/pvclock.h > @@ -11,5 +11,6 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src); > void pvclock_read_wallclock(struct pvclock_wall_clock *wall, > struct pvclock_vcpu_time_info *vcpu, > struct timespec *ts); > +void pvclock_resume(void); > > #endif /* _ASM_X86_PVCLOCK_H */ > diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c > index 239427c..a4f07c1 100644 > --- a/arch/x86/kernel/pvclock.c > +++ b/arch/x86/kernel/pvclock.c > @@ -120,6 +120,11 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src) > > static atomic64_t last_value = ATOMIC64_INIT(0); > > +void pvclock_resume(void) > +{ > + atomic64_set(&last_value, 0); > +} > + > cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) > { > struct pvclock_shadow_time shadow; > diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c > index b2bb5aa..5da5e53 100644 > --- a/arch/x86/xen/time.c > +++ b/arch/x86/xen/time.c > @@ -426,6 +426,8 @@ void xen_timer_resume(void) > { > int cpu; > > + pvclock_resume(); > + > if (xen_clockevent != &xen_vcpuop_clockevent) > return; > > > > > > _______________________________________________ > Virtualization mailing list > Virtualization@lists.linux-foundation.org > https://lists.linux-foundation.org/mailman/listinfo/virtualization -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/