From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59166) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1biHYp-0003pS-5p for qemu-devel@nongnu.org; Fri, 09 Sep 2016 04:53:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1biHYk-0001wY-V0 for qemu-devel@nongnu.org; Fri, 09 Sep 2016 04:53:22 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:45284 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1biHYk-0001wR-PO for qemu-devel@nongnu.org; Fri, 09 Sep 2016 04:53:18 -0400 Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u898rIKV075389 for ; Fri, 9 Sep 2016 04:53:18 -0400 Received: from e06smtp06.uk.ibm.com (e06smtp06.uk.ibm.com [195.75.94.102]) by mx0b-001b2d01.pphosted.com with ESMTP id 25bc2sengg-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 09 Sep 2016 04:53:17 -0400 Received: from localhost by e06smtp06.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 9 Sep 2016 09:53:08 +0100 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id 5DA3C219004D for ; Fri, 9 Sep 2016 09:52:29 +0100 (BST) Received: from d06av01.portsmouth.uk.ibm.com (d06av01.portsmouth.uk.ibm.com [9.149.37.212]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u898r75J24576066 for ; Fri, 9 Sep 2016 08:53:07 GMT Received: from d06av01.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av01.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u898r7xB030025 for ; Fri, 9 Sep 2016 02:53:07 -0600 Date: Fri, 9 Sep 2016 10:53:05 +0200 From: Cornelia Huck In-Reply-To: <20160909104625.648385f1@bahia> References: <147326875705.8546.11347276277137015855.stgit@bahia.lan> <147326876478.8546.16045138068342092499.stgit@bahia.lan> <20160908105926.0d968e64.cornelia.huck@de.ibm.com> <20160908111216.12a1b562@bahia> <20160908175237-mutt-send-email-mst@kernel.org> <20160908170447.2d864945.cornelia.huck@de.ibm.com> <20160908181732-mutt-send-email-mst@kernel.org> <20160908182652.2cf51ac0@bahia> <20160908194939-mutt-send-email-mst@kernel.org> <20160909103053.7f2f7057.cornelia.huck@de.ibm.com> <20160909104625.648385f1@bahia> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-Id: <20160909105305.688fde3d.cornelia.huck@de.ibm.com> Subject: Re: [Qemu-devel] [PATCH 1/2] virtio-9p: print error message and exit instead of BUG_ON() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Greg Kurz Cc: "Michael S. Tsirkin" , qemu-devel@nongnu.org, "Aneesh Kumar K.V" On Fri, 9 Sep 2016 10:46:25 +0200 Greg Kurz wrote: > On Fri, 9 Sep 2016 10:30:53 +0200 > Cornelia Huck wrote: > > > On Thu, 8 Sep 2016 19:55:16 +0300 > > "Michael S. Tsirkin" wrote: > > > > > On Thu, Sep 08, 2016 at 06:26:52PM +0200, Greg Kurz wrote: > > > > On Thu, 8 Sep 2016 18:19:27 +0300 > > > > "Michael S. Tsirkin" wrote: > > > > > > > > > On Thu, Sep 08, 2016 at 05:04:47PM +0200, Cornelia Huck wrote: > > > > > > On Thu, 8 Sep 2016 18:00:28 +0300 > > > > > > "Michael S. Tsirkin" wrote: > > > > > > > > > > > > > On Thu, Sep 08, 2016 at 11:12:16AM +0200, Greg Kurz wrote: > > > > > > If it continues > > > > execution, this means we're expecting the guest or the host to do something > > > > to fix the error condition. This requires QEMU to emit an event of some > > > > sort, but not necessarily to log an error message in a file. I guess this > > > > depends if QEMU is run by some tooling, or by a human. > > > > > > I'm not sure we need an event if tools are not expected to > > > do anything with it. If we limit # of times error > > > is printed, tools will need to reset this counter, > > > so we will need an event on overflow. > > > > If the device goes into a broken state, it should be discoverable from > > outside. I'm not sure we need an actual event signalling this if this > > happens due to the guest doing something wrong: That would be a task > > for tools monitoring _inside_ the guest. > > Well, in case of a virtio device being broken, section 2.1.2 in the spec > suggests to set the status to DEVICE_NEEDS_RESET and to notify it to > the guest (aka. event signalling). I'll send a patch shortly. Stefan had already sent <1460467534-29147-4-git-send-email-stefanha@redhat.com> ages ago, but it has not yet made it anywhere... Anyhow, I was concerned with host signalling (sorry for being unclear), and I still do not think we need to alert host monitoring software to guest stupidity. > > > For tools monitoring the > > health of the machine (from the host perspective), the discovery > > interface would probably be enough? > > > > Yeah, probably. > > Cheers. > > -- > Greg >