From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Bugs in kvm guest migration Date: Fri, 04 Dec 2009 09:59:50 +0200 Message-ID: <4B18C176.7050105@redhat.com> References: <4B17DB29.9060801@siemens.com> <4B181033.1020804@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm , qemu-devel To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:1472 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753539AbZLDH7w (ORCPT ); Fri, 4 Dec 2009 02:59:52 -0500 In-Reply-To: <4B181033.1020804@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 12/03/2009 09:23 PM, Jan Kiszka wrote: > Jan Kiszka wrote: > >> Problem 2 >> --------- >> Setup: qemu head with vmstate fixes. kvm-kmod master, 64-bit host& guest. >> Effect: The migration target either locks up or reboots immediately. >> I've nailed this down to 84d0b66c778d881eafca2a5d0d66678211c4e861. Every >> kvm module build before that works, everything including and after >> 26ede77f536d1bb369527a96c7fe7fdc8ba2f890 shows the effect (everything in >> between crashes the host for known reasons). It's still unclear if this >> is an kvm-kmod wrapping issue of the user-space return notifiers. Will >> check once problem #1 is understood. >> > It is kernel-related, using kvm.git as host kernel makes no difference. > > This may now mean that kvm is buggy or that it triggers some msr > save/restore related issues in qemu. Digging even deeper... > Does calling drop_user_return_notifiers() (static in x86.c, will need exporting) in vmx_load_host_state() within the preempt-disable region help? -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.