From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Berger Subject: Re: Errors on MMIO read access on VM suspend / resume operations Date: Mon, 17 Jan 2011 22:03:42 -0500 Message-ID: <4D35030E.4080406@linux.vnet.ibm.com> References: <4D2C8305.2090609@linux.vnet.ibm.com> <4D2ED260.4010801@redhat.com> <4D30A38F.3030002@linux.vnet.ibm.com> <4D3303FD.8020509@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org To: Avi Kivity Return-path: Received: from e33.co.us.ibm.com ([32.97.110.151]:45099 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753444Ab1ARDDu (ORCPT ); Mon, 17 Jan 2011 22:03:50 -0500 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e33.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id p0I2vhse011541 for ; Mon, 17 Jan 2011 19:57:43 -0700 Received: from d03av06.boulder.ibm.com (d03av06.boulder.ibm.com [9.17.195.245]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id p0I33lj3252392 for ; Mon, 17 Jan 2011 20:03:47 -0700 Received: from d03av06.boulder.ibm.com (loopback [127.0.0.1]) by d03av06.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p0I38GWC030115 for ; Mon, 17 Jan 2011 20:08:16 -0700 In-Reply-To: <4D3303FD.8020509@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 01/16/2011 09:43 AM, Avi Kivity wrote: > On 01/14/2011 09:27 PM, Stefan Berger wrote: >> >>> >>> Can you sprinkle some printfs() arount kvm_run (in qemu-kvm.c) to >>> verify this? >>> >> Here's what I did: >> >> >> interrupt exit requested > > It appears from this you're using qemu.git. Please try qemu-kvm.git, > where the code appears to be correct. > Cc'ing qemu-devel now. For reference, here the initial problem description: http://www.spinics.net/lists/kvm/msg48274.html I didn't know there was another tree... I have seen now a couple of suspends-while-reading with patches applied to the qemu-kvm.git tree and indeed, when run with the same host kernel and VM I do not see the debugging dumps due to double-reads that I would have anticipated seeing by now. Now what? Can this be easily fixed in the other Qemu tree as well? One thing I'd like to mention is that I have seen what I think are interrupt stalls when running my tests inside the qemu-kvm.git tree version and not suspending at all. A some point the interrupt counter in the guest kernel does not increase anymore even though I see the device model raising the IRQ and lowering it. The same tests run literally forever in the qemu.git tree version of Qemu. Regards, Stefan From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=53469 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Pf1rP-0007xO-Mj for qemu-devel@nongnu.org; Mon, 17 Jan 2011 22:03:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Pf1rO-000137-L4 for qemu-devel@nongnu.org; Mon, 17 Jan 2011 22:03:55 -0500 Received: from e31.co.us.ibm.com ([32.97.110.149]:43518) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Pf1rO-000123-Fx for qemu-devel@nongnu.org; Mon, 17 Jan 2011 22:03:54 -0500 Received: from d03relay01.boulder.ibm.com (d03relay01.boulder.ibm.com [9.17.195.226]) by e31.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id p0I2nWGl022912 for ; Mon, 17 Jan 2011 19:49:32 -0700 Received: from d03av06.boulder.ibm.com (d03av06.boulder.ibm.com [9.17.195.245]) by d03relay01.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p0I33l4B171272 for ; Mon, 17 Jan 2011 20:03:47 -0700 Received: from d03av06.boulder.ibm.com (loopback [127.0.0.1]) by d03av06.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p0I38GW8030115 for ; Mon, 17 Jan 2011 20:08:16 -0700 Message-ID: <4D35030E.4080406@linux.vnet.ibm.com> Date: Mon, 17 Jan 2011 22:03:42 -0500 From: Stefan Berger MIME-Version: 1.0 References: <4D2C8305.2090609@linux.vnet.ibm.com> <4D2ED260.4010801@redhat.com> <4D30A38F.3030002@linux.vnet.ibm.com> <4D3303FD.8020509@redhat.com> In-Reply-To: <4D3303FD.8020509@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: Errors on MMIO read access on VM suspend / resume operations List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org On 01/16/2011 09:43 AM, Avi Kivity wrote: > On 01/14/2011 09:27 PM, Stefan Berger wrote: >> >>> >>> Can you sprinkle some printfs() arount kvm_run (in qemu-kvm.c) to >>> verify this? >>> >> Here's what I did: >> >> >> interrupt exit requested > > It appears from this you're using qemu.git. Please try qemu-kvm.git, > where the code appears to be correct. > Cc'ing qemu-devel now. For reference, here the initial problem description: http://www.spinics.net/lists/kvm/msg48274.html I didn't know there was another tree... I have seen now a couple of suspends-while-reading with patches applied to the qemu-kvm.git tree and indeed, when run with the same host kernel and VM I do not see the debugging dumps due to double-reads that I would have anticipated seeing by now. Now what? Can this be easily fixed in the other Qemu tree as well? One thing I'd like to mention is that I have seen what I think are interrupt stalls when running my tests inside the qemu-kvm.git tree version and not suspending at all. A some point the interrupt counter in the guest kernel does not increase anymore even though I see the device model raising the IRQ and lowering it. The same tests run literally forever in the qemu.git tree version of Qemu. Regards, Stefan