From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: VM not booting anymore after Ubuntu upgrade
Date: Wed, 04 Aug 2010 13:31:21 +0300
Message-ID: <4C594179.6010609@redhat.com>
References: <4C58FD2F.9050708@web.de> <4C590D25.4070302@redhat.com> <4C590EC9.1080209@web.de> <4C59113E.8020907@redhat.com> <4C59190D.8050007@web.de>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1;
	format=flowed
Content-Transfer-Encoding: QUOTED-PRINTABLE
Cc: kvm@vger.kernel.org
To: =?ISO-8859-1?Q?Andr=E9_Weidemann?= <Andre.Weidemann@web.de>
Return-path: <kvm-owner@vger.kernel.org>
Received: from mx1.redhat.com ([209.132.183.28]:1025 "EHLO mx1.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1756983Ab0HDKb1 (ORCPT <rfc822;kvm@vger.kernel.org>);
	Wed, 4 Aug 2010 06:31:27 -0400
In-Reply-To: <4C59190D.8050007@web.de>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

  On 08/04/2010 10:38 AM, Andr=E9 Weidemann wrote:
>
>> Please enable ftrace:
>>
>> # mount -t debugfs debugfs /sys/kernel/debug
>> # cd /sys/kernel/debug/tracing
>> # echo 100000 > buffer_size_kb
>> # echo kvm > set_event
>> # echo 1 > tracing on
>>
>> run the guest and kill qemu immediately when you get to the blank sc=
reen
>> (use SDL so you can see it immediately). Then post
>> /sys/kernel/debug/trace somewhere.
>
> I ran the trace and put the ouptut here:
> http://ilpss8.dyndns.org/~andrew/qemu-kvm.trace.gz
>


<...>-26008 [001] 5175193.046430: kvm_exit: reason exception rip 0xfc84=
2
<...>-26008 [001] 5175193.046430: kvm_page_fault: address fc842 error_c=
ode 9
<...>-26008 [001] 5175193.046432: kvm_entry: vcpu 0
<...>-26008 [001] 5175193.046434: kvm_exit: reason cr_access rip 0xfc79=
6
<...>-26008 [001] 5175193.046435: kvm_cr: cr_write 0 =3D 0x10
<...>-26008 [001] 5175193.046442: kvm_entry: vcpu 0
<...>-26008 [001] 5175193.046444: kvm_exit: reason exception rip 0xfc79=
9
<...>-26008 [001] 5175193.046447: kvm_entry: vcpu 0
<...>-26008 [001] 5175193.046449: kvm_exit: reason exception rip 0xfc79=
9
<...>-26008 [001] 5175193.046449: kvm_page_fault: address feffd066=20
error_code 9
<...>-26008 [001] 5175193.046453: kvm_inj_virq: irq 13

#GP at fc799.

    fc78f:       0f 20 c0                mov    %cr0,%eax
    fc792:       66 83 e0 fe             and    $0xfffffffe,%eax
    fc796:       0f 22 c0                mov    %eax,%cr0
    fc799:       ea 9e c7 00 f0          ljmp   $0xf000,$0xc79e

I think we're in big real mode and your kernel has trouble emulating th=
e=20
ljmp.  Can you try latest seabios[1]?  Commit 0f788893a8bba has a=20
workaround.


[1] git://git.linuxtogo.org/home/kevin/seabios.git

--=20
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.