From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:35852) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S7kS8-0002zA-Rc for qemu-devel@nongnu.org; Wed, 14 Mar 2012 05:25:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S7kRk-0006dp-8f for qemu-devel@nongnu.org; Wed, 14 Mar 2012 05:25:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33112) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S7kRk-0006bc-0Q for qemu-devel@nongnu.org; Wed, 14 Mar 2012 05:24:40 -0400 Message-ID: <4F6063C8.8010005@redhat.com> Date: Wed, 14 Mar 2012 11:24:24 +0200 From: Avi Kivity MIME-Version: 1.0 References: <4F58664D.1070800@cn.fujitsu.com> <4F58943E.1050402@redhat.com> <4F595B31.9090301@cn.fujitsu.com> <4F5DBC26.7060204@cn.fujitsu.com> <4F5DD0FD.9070904@redhat.com> <20120313091843.GB3800@redhat.com> <4F5F25BF.7060100@redhat.com> <4F6056FE.3020202@cn.fujitsu.com> In-Reply-To: <4F6056FE.3020202@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 0/2 v3] kvm: notify host when guest panicked List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wen Congyang Cc: Gleb Natapov , kvm list , Jan Kiszka , qemu-devel , "linux-kernel@vger.kernel.org" , Amit Shah , KAMEZAWA Hiroyuki On 03/14/2012 10:29 AM, Wen Congyang wrote: > At 03/13/2012 06:47 PM, Avi Kivity Wrote: > > On 03/13/2012 11:18 AM, Daniel P. Berrange wrote: > >> On Mon, Mar 12, 2012 at 12:33:33PM +0200, Avi Kivity wrote: > >>> On 03/12/2012 11:04 AM, Wen Congyang wrote: > >>>> Do you have any other comments about this patch? > >>>> > >>> > >>> Not really, but I'm not 100% convinced the patch is worthwhile. It's > >>> likely to only be used by Linux, which has kexec facilities, and you can > >>> put talk to management via virtio-serial and describe the crash in more > >>> details than a simple hypercall. > >> > >> As mentioned before, I don't think virtio-serial is a good fit for this. > >> We want something that is simple & guaranteed always available. Using > >> virtio-serial requires significant setup work on both the host and guest. > > > > So what? It needs to be done anyway for the guest agent. > > > >> Many management application won't know to make a vioserial device available > >> to all guests they create. > > > > Then they won't know to deal with the panic event either. > > > >> Most administrators won't even configure kexec, > >> let alone virtio serial on top of it. > > > > It should be done by the OS vendor, not the individual admin. > > > >> The hypercall requires zero host > >> side config, and zero guest side config, which IMHO is what we need for > >> this feature. > > > > If it was this one feature, yes. But we keep getting more and more > > features like that and we bloat the hypervisor. There's a reason we > > have a host-to-guest channel, we should use it. > > > > I donot know how to use virtio-serial. I don't either, copying Amit. > I start vm like this: > qemu ...\ > -device virtio-serial \ > -chardev socket,path=/tmp/foo,server,nowait,id=foo \ > -device virtserialport,chardev=foo,name=port1 ... > > You said that there are too many channels. Does it mean /tmp/foo is a channel? Probably. -- error compiling committee.c: too many arguments to function