From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932734Ab2GYDZw (ORCPT ); Tue, 24 Jul 2012 23:25:52 -0400 Received: from ozlabs.org ([203.10.76.45]:40774 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932639Ab2GYDZv (ORCPT ); Tue, 24 Jul 2012 23:25:51 -0400 From: Rusty Russell To: Sasha Levin , dlaor@redhat.com Cc: 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, "Peter Maydell" , "Amit Shah" Subject: Re: [RFC 0/2] virtio: provide a way for host to monitor critical events in the device In-Reply-To: <500E9CC7.9020201@gmail.com> References: <1343075561-29316-1-git-send-email-levinsasha928@gmail.com> <87a9yprc4v.fsf@rustcorp.com.au> <500E5C36.2070601@redhat.com> <500E954F.8090102@gmail.com> <500E9942.3080505@redhat.com> <500E9CC7.9020201@gmail.com> User-Agent: Notmuch/0.12 (http://notmuchmail.org) Emacs/23.3.1 (i686-pc-linux-gnu) Date: Wed, 25 Jul 2012 10:06:37 +0930 Message-ID: <87haswptgq.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 24 Jul 2012 15:01:59 +0200, Sasha Levin wrote: > virtio on it's own was introduced to help solve the fragmentation > around virtualized devices, so I don't think that the main purpose of > doing virtio drivers is due to any performance benefits virtio may > provide. There's one argument in your favor (with my Linaro hat on): ARM wants a virtio reboot button, which would look remarkably similar. There's no standard ARM hardware for this. So a more generalized virtio-event device might make sense. But there are almost an infinite number of guest events we might want: panics, oom, low memory, stuck devices, deadlock, etc, etc. I'm concerned about trying to standardize them. If we include a unspecified free-form string, people will end up relying on the contents. If we add a feature bit for every new event, we'll end up running out of feature bits :) CC'ing Amit for opinion over how much of this should be done via virtio-serial. Cheers, Rusty.