From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uri Lublin Subject: Re: Migration problems Date: Thu, 24 Jan 2008 13:52:16 +0200 Message-ID: <47987BF0.7030005@qumranet.com> References: <47979986.1060409@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Chris Lalancette Return-path: In-Reply-To: <47979986.1060409-H+wXaHxf7aLQT0dZR+AlfA@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 Chris Lalancette wrote: > All, > I've been doing some migration testing of KVM guests, and have been running > into some problems. Let me describe the setup and what I've tried, and maybe > somebody has some ideas about what might be going on here. > > When I try to do > live migration this way, things seem like they work, and it even seems like a > few instructions get executed on the destination side. However, fairly quickly > I'll get "Disabling IRQ #11" on the console of the guest at the destination, and > the qemu process will just spin at 100%, with no interaction possible. IRQ #11, > incidentally, is the IRQ associated with the emulated rtl8139 card. > > This led me to suspect the in-kernel PIC/APIC emulation, and, sure enough, if I > pass -no-kvm-irqchip (on both the source and destination), things are better; I > can at least migrate from the host to the destination without the "Disabling IRQ > #11" message. However, if I put any sort of load on the guest while doing > migration, I still get a hang-up, even with -no-kvm-irqchip. > > Has anyone else seen this, or have ideas where I can start debugging it? > > Thanks, > Chris Lalancette > Hi Chris, I am chasing migration bug(s) too. I think the problem lies in userspace and not in the kernel modules. It seems that for kvm-56 migration works but for kvm-57 it does not. The problem seems to be related to the qemu-cvs merge: 25a2e04e5689af63d104de2dea755f30bf643afd If you run it with -no-kvm migration seems to be working. The test case I'm using is savevm/loadvm. After a loadvm my FC6 guest gets double-fault ( -loadvm ). Adding '-no-kvm-irqchip' does not help. But if I start qemu in a stopped mode ( -S) and 'loadvm ' in qemu-monitor, it works. Sometimes after lodavm guest network does work better with '-no-kvm-irqchip' I am trying to use bisection to find the problematic patch. Thanks, Uri. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/