From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753827Ab2GXMdM (ORCPT ); Tue, 24 Jul 2012 08:33:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:8580 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753378Ab2GXMdL (ORCPT ); Tue, 24 Jul 2012 08:33:11 -0400 Date: Tue, 24 Jul 2012 15:33:01 +0300 From: Gleb Natapov To: Sasha Levin Cc: rusty@rustcorp.com.au, mst@redhat.com, penberg@kernel.org, asias.hejun@gmail.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, avi@redhat.com, anthony@codemonkey.ws, wency@cn.fujitsu.com Subject: Re: [RFC 0/2] virtio: provide a way for host to monitor critical events in the device Message-ID: <20120724123301.GH26120@redhat.com> References: <1343075561-29316-1-git-send-email-levinsasha928@gmail.com> <20120724074434.GE26120@redhat.com> <500E9479.3050405@gmail.com> <20120724122824.GG26120@redhat.com> <500E959D.70009@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <500E959D.70009@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 24, 2012 at 02:31:25PM +0200, Sasha Levin wrote: > On 07/24/2012 02:28 PM, Gleb Natapov wrote: > > On Tue, Jul 24, 2012 at 02:26:33PM +0200, Sasha Levin wrote: > >> On 07/24/2012 09:44 AM, Gleb Natapov wrote: > >>> On Mon, Jul 23, 2012 at 10:32:39PM +0200, Sasha Levin wrote: > >>>> As it was discussed recently, there's currently no way for the guest to notify > >>>> the host about panics. Further more, there's no reasonable way to notify the > >>>> host of other critical events such as an OOM kill. > >>>> > >>>> This short patch series introduces a new device named virtio-notifier which > >>>> does two simple things: > >>>> > >>>> 1. Provide a simple interface for the guest to notify the host of critical > >>> To get early OOPSes virtio will have to be compiled into the kernel. If > >>> your are so keen on using virtio for this though, why not just use > >>> dedicated virtio serial channel? > >> > >> Let's separate between having log for these events and receiving notifications about them. > >> > >> For the log part, I can already run a simple serial console to dump everything somewhere. I'm more concerned about having notifications about something critical happening when the guest is already up and running. > >> > > I am talking about notifications. Run your notification protocol over > > dedicated virtio-serial channel. Logs goes to virtio-console as you've > > said. > > Ah, so just add another channel into virtio-serial to pass these notifications? Good idea - I'll look into it. > Yes, that's what I mean. This solution still has the disadvantage of not been able to catch early boot oopses without compiling the whole virtio into a kernel image. -- Gleb. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [RFC 0/2] virtio: provide a way for host to monitor critical events in the device Date: Tue, 24 Jul 2012 15:33:01 +0300 Message-ID: <20120724123301.GH26120@redhat.com> References: <1343075561-29316-1-git-send-email-levinsasha928@gmail.com> <20120724074434.GE26120@redhat.com> <500E9479.3050405@gmail.com> <20120724122824.GG26120@redhat.com> <500E959D.70009@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: wency@cn.fujitsu.com, kvm@vger.kernel.org, mst@redhat.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, penberg@kernel.org, avi@redhat.com, anthony@codemonkey.ws To: Sasha Levin Return-path: Content-Disposition: inline In-Reply-To: <500E959D.70009@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: kvm.vger.kernel.org On Tue, Jul 24, 2012 at 02:31:25PM +0200, Sasha Levin wrote: > On 07/24/2012 02:28 PM, Gleb Natapov wrote: > > On Tue, Jul 24, 2012 at 02:26:33PM +0200, Sasha Levin wrote: > >> On 07/24/2012 09:44 AM, Gleb Natapov wrote: > >>> On Mon, Jul 23, 2012 at 10:32:39PM +0200, Sasha Levin wrote: > >>>> As it was discussed recently, there's currently no way for the guest to notify > >>>> the host about panics. Further more, there's no reasonable way to notify the > >>>> host of other critical events such as an OOM kill. > >>>> > >>>> This short patch series introduces a new device named virtio-notifier which > >>>> does two simple things: > >>>> > >>>> 1. Provide a simple interface for the guest to notify the host of critical > >>> To get early OOPSes virtio will have to be compiled into the kernel. If > >>> your are so keen on using virtio for this though, why not just use > >>> dedicated virtio serial channel? > >> > >> Let's separate between having log for these events and receiving notifications about them. > >> > >> For the log part, I can already run a simple serial console to dump everything somewhere. I'm more concerned about having notifications about something critical happening when the guest is already up and running. > >> > > I am talking about notifications. Run your notification protocol over > > dedicated virtio-serial channel. Logs goes to virtio-console as you've > > said. > > Ah, so just add another channel into virtio-serial to pass these notifications? Good idea - I'll look into it. > Yes, that's what I mean. This solution still has the disadvantage of not been able to catch early boot oopses without compiling the whole virtio into a kernel image. -- Gleb.