From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1NGT59-0006AR-ST
	for qemu-devel@nongnu.org; Fri, 04 Dec 2009 03:00:03 -0500
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1NGT54-00067Y-M3
	for qemu-devel@nongnu.org; Fri, 04 Dec 2009 03:00:02 -0500
Received: from [199.232.76.173] (port=42117 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1NGT54-00067V-HJ
	for qemu-devel@nongnu.org; Fri, 04 Dec 2009 02:59:58 -0500
Received: from mx20.gnu.org ([199.232.41.8]:43534)
	by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32)
	(Exim 4.60) (envelope-from <avi@redhat.com>) id 1NGT54-0003AO-4H
	for qemu-devel@nongnu.org; Fri, 04 Dec 2009 02:59:58 -0500
Received: from mx1.redhat.com ([209.132.183.28])
	by mx20.gnu.org with esmtp (Exim 4.60)
	(envelope-from <avi@redhat.com>) id 1NGT52-0004Sn-SO
	for qemu-devel@nongnu.org; Fri, 04 Dec 2009 02:59:57 -0500
Message-ID: <4B18C176.7050105@redhat.com>
Date: Fri, 04 Dec 2009 09:59:50 +0200
From: Avi Kivity <avi@redhat.com>
MIME-Version: 1.0
References: <4B17DB29.9060801@siemens.com> <4B181033.1020804@siemens.com>
In-Reply-To: <4B181033.1020804@siemens.com>
Content-Type: text/plain; charset=ISO-8859-15; format=flowed
Content-Transfer-Encoding: 7bit
Subject: [Qemu-devel] Re: Bugs in kvm guest migration
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>, qemu-devel <qemu-devel@nongnu.org>, kvm <kvm@vger.kernel.org>

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.