Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756776AbXLSO1f (ORCPT ); Wed, 19 Dec 2007 09:27:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753884AbXLSO1X (ORCPT ); Wed, 19 Dec 2007 09:27:23 -0500 Received: from il.qumranet.com ([82.166.9.18]:60401 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753871AbXLSO1V (ORCPT ); Wed, 19 Dec 2007 09:27:21 -0500 Message-ID: <47692A47.4040803@argo.co.il> Date: Wed, 19 Dec 2007 16:27:19 +0200 From: Avi Kivity User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Ingo Molnar CC: Avi Kivity , kvm-devel , linux-kernel Subject: Re: [kvm-devel] Guest kernel hangs in smp kvm for older kernels prior to tsc sync cleanup References: <47680173.6060606@qumranet.com> <20071218221930.GA26109@elte.hu> <4768BB43.1000609@qumranet.com> <4768FE27.7020305@qumranet.com> <47690304.1090903@qumranet.com> <20071219140624.GF21282@elte.hu> In-Reply-To: <20071219140624.GF21282@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 967 Lines: 33 Ingo Molnar wrote: > * Avi Kivity wrote: > > >> Avi Kivity wrote: >> >>> Testing shows wrmsr and rdtsc function normally. >>> >>> I'll try pinning the vcpus to cpus and see if that helps. >>> >>> >> It does. >> > > do we let the guest read the physical CPU's TSC? That would be trouble. > > vmx (and svm) allow us to add an offset to the physical tsc. We set it on startup to -tsc (so that an rdtsc on boot would return 0), and massage it on vcpu migration so that guest rdtsc is monotonic. The net effect is that tsc on a vcpu can experience large forward jumps and changes in rate, but no negative jumps. -- error compiling committee.c: too many arguments to function -- 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/