From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: [PATCH 09/11] KVM: Move kvm_guest_exit() after local_irq_enable() Date: Sun, 21 Oct 2007 13:08:10 +0200 Message-ID: <11929648921683-git-send-email-avi@qumranet.com> References: <1192964892617-git-send-email-avi@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Laurent Vivier , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Avi Kivity To: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Return-path: In-Reply-To: <1192964892617-git-send-email-avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org From: Laurent Vivier We need to make sure that the timer interrupt happens before we clear PF_VCPU, so the accounting code actually sees guest mode. http://lkml.org/lkml/2007/10/15/114 Signed-off-by: Laurent Vivier Signed-off-by: Avi Kivity --- drivers/kvm/kvm_main.c | 11 ++++++++++- 1 files changed, 10 insertions(+), 1 deletions(-) diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c index af2d288..8c458f2 100644 --- a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c @@ -2054,12 +2054,21 @@ again: kvm_x86_ops->run(vcpu, kvm_run); - kvm_guest_exit(); vcpu->guest_mode = 0; local_irq_enable(); ++vcpu->stat.exits; + /* + * We must have an instruction between local_irq_enable() and + * kvm_guest_exit(), so the timer interrupt isn't delayed by + * the interrupt shadow. The stat.exits increment will do nicely. + * But we need to prevent reordering, hence this barrier(): + */ + barrier(); + + kvm_guest_exit(); + preempt_enable(); /* -- 1.5.3 ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/