From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:54046) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S7liq-0002Y6-2A for qemu-devel@nongnu.org; Wed, 14 Mar 2012 06:46:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S7lii-0001C5-AQ for qemu-devel@nongnu.org; Wed, 14 Mar 2012 06:46:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59300) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S7lii-0001Bz-2g for qemu-devel@nongnu.org; Wed, 14 Mar 2012 06:46:16 -0400 Date: Wed, 14 Mar 2012 12:46:08 +0200 From: Gleb Natapov Message-ID: <20120314104608.GU2304@redhat.com> References: <4F5DBC26.7060204@cn.fujitsu.com> <4F5DD0FD.9070904@redhat.com> <20120313091843.GB3800@redhat.com> <4F5F25BF.7060100@redhat.com> <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F607325.6050607@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 12:29:57PM +0200, Avi Kivity wrote: > On 03/14/2012 12:26 PM, Wen Congyang wrote: > > >> If so, is this channel visible to guest userspace? If the channle is visible to guest > > >> userspace, the program running in userspace may write the same message to the channel. > > >> > > > > > > Surely there's some kind of access control on channels. > > > > The virtio-serial depends on more things than touching the hypervisor. So I think touching > > the hypervisor is more reliable than using virtio-serial device, and it is very simple and > > easy to use. > > > > If we pass something from guest userspace to host, we can use virtio-serial. But If we pass > > something from guest kernelspace to host, I still prefer to touch the hypervisor. > > There's no argument that it's easier. My concern is different, we're > adding more and more stuff to the hypervisor because it's easier, which > bloats it. Every time we do it we add to compatibility and security > problems. > > The panic notification is *really* simple, so I don't expect it to cause > a lot of problems. But still, if it's possible not to change the > hypervisor, we must make an effort in that direction. > One more point against using virtio-serial is that it will be likely compiled as a module which means panic during early boot will not be reported. -- Gleb.