From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:40401) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S7o2e-0002v9-Ny for qemu-devel@nongnu.org; Wed, 14 Mar 2012 09:15:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S7o22-0002f8-0H for qemu-devel@nongnu.org; Wed, 14 Mar 2012 09:15:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20490) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S7o21-0002f1-OK for qemu-devel@nongnu.org; Wed, 14 Mar 2012 09:14:21 -0400 Date: Wed, 14 Mar 2012 15:14:15 +0200 From: Gleb Natapov Message-ID: <20120314131415.GB2304@redhat.com> References: <4F6056FE.3020202@cn.fujitsu.com> <4F6063C8.8010005@redhat.com> <4F606A7C.9090900@cn.fujitsu.com> <4F606DCC.3020908@redhat.com> <4F60726E.3090807@cn.fujitsu.com> <4F607325.6050607@redhat.com> <20120314104608.GU2304@redhat.com> <4F607789.4010109@redhat.com> <4F607CE4.2060809@cn.fujitsu.com> <4F609822.7050502@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F609822.7050502@redhat.com> 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: Avi Kivity Cc: kvm list , Jan Kiszka , "linux-kernel@vger.kernel.org" , qemu-devel , Amit Shah , KAMEZAWA Hiroyuki On Wed, Mar 14, 2012 at 03:07:46PM +0200, Avi Kivity wrote: > On 03/14/2012 01:11 PM, Wen Congyang wrote: > > > > > > I don't think we want to use the driver. Instead, have a small piece of > > > code that resets the device and pushes out a string (the panic message?) > > > without any interrupts etc. > > > > > > It's still going to be less reliable than a hypercall, I agree. > > > > Do you still want to use complicated and less reliable way? > > Are you willing to try it out and see how complicated it really is? > > While it's more complicated, it's also more flexible. You can > communicate the panic message, whether the guest is attempting a kdump > and its own recovery or whether it wants the host to do it, etc., you > can communicate less severe failures like oopses. > hypercall can take arguments to achieve the same. > > I think the other ones prefer to touch the hypervisor. > > I understand the sentiment. Your patches are simple and easy. But my > feeling is that the kernel has become too complicated already and I'm > looking for ways to limit changes. > Using virtio-serial will not reduce kernel complexity. Quite contrary since code that will use virtio-serial will be more complicated. -- Gleb.