From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755282Ab1B1QhH (ORCPT ); Mon, 28 Feb 2011 11:37:07 -0500 Received: from kroah.org ([198.145.64.141]:41214 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755226Ab1B1QhC (ORCPT ); Mon, 28 Feb 2011 11:37:02 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Mon Feb 28 08:24:06 2011 Message-Id: <20110228162406.752962160@clark.kroah.org> User-Agent: quilt/0.48-11.2 Date: Mon, 28 Feb 2011 08:22:32 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jeremy Fitzhardinge , Ingo Molnar Subject: [11/68] x86/pvclock: Zero last_value on resume In-Reply-To: <20110228163502.GA27221@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Jeremy Fitzhardinge commit e7a3481c0246c8e45e79c629efd63b168e91fcda upstream. 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. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/pvclock.h | 1 + arch/x86/kernel/pvclock.c | 5 +++++ arch/x86/xen/time.c | 2 ++ 3 files changed, 8 insertions(+) --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -10,5 +10,6 @@ unsigned long pvclock_tsc_khz(struct pvc 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 */ --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -111,6 +111,11 @@ unsigned long pvclock_tsc_khz(struct pvc 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; --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -424,6 +424,8 @@ void xen_timer_resume(void) { int cpu; + pvclock_resume(); + if (xen_clockevent != &xen_vcpuop_clockevent) return;