From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756886AbXGXFfa (ORCPT ); Tue, 24 Jul 2007 01:35:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752210AbXGXFfU (ORCPT ); Tue, 24 Jul 2007 01:35:20 -0400 Received: from il.qumranet.com ([82.166.9.18]:57834 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750912AbXGXFfS (ORCPT ); Tue, 24 Jul 2007 01:35:18 -0400 Message-ID: <46A58F88.9050906@qumranet.com> Date: Tue, 24 Jul 2007 08:35:04 +0300 From: Avi Kivity User-Agent: Thunderbird 2.0.0.4 (X11/20070615) MIME-Version: 1.0 To: Shaohua Li CC: kvm-devel , lkml , Ingo Molnar Subject: Re: [RFC 1/8]KVM: fix bugs in kvm sched integration patch References: <1185173492.2645.65.camel@sli10-conroe.sh.intel.com> <46A48713.9080404@qumranet.com> <1185241544.24201.15.camel@sli10-conroe.sh.intel.com> In-Reply-To: <1185241544.24201.15.camel@sli10-conroe.sh.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (firebolt.argo.co.il [0.0.0.0]); Tue, 24 Jul 2007 08:35:04 +0300 (IDT) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Shaohua Li wrote: >> >>> 1. vmcs_readl/vmcs_writel are called with preempt enabled >>> >>> >> Why is that bad? >> > 1. raw_smp_processor_id() > 2. migrate to other cpu > 3. current->kvm_vcpu->cpu != the cpu id of step 1. > you will see the warning. > Ah, that code is gone from preempt-hooks, hence I didn't understand you. The current version of the patchset does not change vmcs_readl/vmcs_writel. So I think everything is safe. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.