Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753798Ab2KTVeX (ORCPT ); Tue, 20 Nov 2012 16:34:23 -0500 Received: from mx1.redhat.com ([209.132.183.28]:23587 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753172Ab2KTVeV (ORCPT ); Tue, 20 Nov 2012 16:34:21 -0500 Date: Tue, 20 Nov 2012 19:33:49 -0200 From: Marcelo Tosatti To: Hu Tao Cc: Sasha Levin , Wen Congyang , kvm list , qemu-devel , "linux-kernel@vger.kernel.org" , Avi Kivity , "Daniel P. Berrange" , KAMEZAWA Hiroyuki , Jan Kiszka , Gleb Natapov , Blue Swirl , Eric Blake , Andrew Jones , Luiz Capitulino Subject: Re: [PATCH v11] kvm: notify host when the guest is panicked Message-ID: <20121120213349.GA31355@amt.cnet> References: <0a2274eccf1b1dd420f16359f7e1de74fa2f9fbe.1351131144.git.hutao@cn.fujitsu.com> <20121031011256.GC12325@amt.cnet> <50908354.5070608@cn.fujitsu.com> <20121106015835.GA11971@localhost.localdomain> <20121113021908.GA8176@amt.cnet> <20121120100948.GB17311@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121120100948.GB17311@localhost.localdomain> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2671 Lines: 69 On Tue, Nov 20, 2012 at 06:09:48PM +0800, Hu Tao wrote: > Hi Marcelo, > > On Tue, Nov 13, 2012 at 12:19:08AM -0200, Marcelo Tosatti wrote: > > On Fri, Nov 09, 2012 at 03:17:39PM -0500, Sasha Levin wrote: > > > On Mon, Nov 5, 2012 at 8:58 PM, Hu Tao wrote: > > > > But in the case of panic notification, more dependency means more > > > > chances of failure of panic notification. Say, if we use a virtio device > > > > to do panic notification, then we will fail if: virtio itself has > > > > problems, virtio for some reason can't be deployed(neither built-in or > > > > as a module), or guest doesn't support virtio, etc. > > > > > > Add polling to your virtio device. If it didn't notify of a panic but > > > taking more than 20 sec to answer your poll request you can assume > > > it's dead. > > > > > > Actually, just use virtio-serial and something in userspace on the guest. > > > > They want the guest to stop, so a memory dump can be taken by management > > interface. > > > > Hu Tao, lets assume port I/O is the preferred method for communication. > > Okey. > > > Now, the following comments have still not been addressed: > > > > 1) Lifecycle of the stopped guest and interaction with other stopped > > states in QEMU. > > Patch 3 already deals with run state transitions. But in case I'm > missing something, could you be more specific? - What are the possibilities during migration? Say: - migration starts. - guest panics. - migration starts vm on other side? - Guest stopped due to EIO. - guest vcpuN panics, VMEXIT but still outside QEMU. - QEMU EIO error, stop vm. - guest vcpuN completes, processes IO exit. - system_reset due to panic. - Add all possibilities that should be verified (that is, interaction of this feature with other stopped states in QEMU). --- - What happens if the guest has reboot-on-panic configured? Does it take precedence over hypervisor notification? Out of curiosity, does kexec support memory dumping? > > 2) Format of the interface for other architectures (you can choose > > a different KVM supported architecture and write an example). > > > > 3) Clear/documented management interface for the feature. > > It is documented in patch 0: Documentation/virtual/kvm/pv_event.txt. > Does it need to be improved? This is documentation for the host<->guest interface. There is no documentation on the interface for management. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/