From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030274Ab2CTXmK (ORCPT ); Tue, 20 Mar 2012 19:42:10 -0400 Received: from ozlabs.org ([203.10.76.45]:56581 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755478Ab2CTXmJ (ORCPT ); Tue, 20 Mar 2012 19:42:09 -0400 From: Rusty Russell To: "Michael S. Tsirkin" Cc: Jason Wang , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, qemu-devel@nongnu.org, Christian Borntraeger Subject: Re: [PATCH] virtio-spec: clarify ro/rw bits and updating rule of virtio-net status field In-Reply-To: <20120320224805.GA4997@redhat.com> References: <20120320062020.12815.61342.stgit@jason-ThinkPad-T400> <87ty1jpm6p.fsf@rustcorp.com.au> <20120320224805.GA4997@redhat.com> User-Agent: Notmuch/0.6.1-1 (http://notmuchmail.org) Emacs/23.3.1 (i686-pc-linux-gnu) Date: Wed, 21 Mar 2012 10:10:52 +1030 Message-ID: <87ty1ializ.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 Wed, 21 Mar 2012 00:48:05 +0200, "Michael S. Tsirkin" wrote: > On Tue, Mar 20, 2012 at 09:35:18PM +1030, Rusty Russell wrote: > > On Tue, 20 Mar 2012 14:20:21 +0800, Jason Wang wrote: > > > This patch clarifies VIRTIO_NET_S_LINK_UP as a read-only bit and > > > VIRTIO_NET_S_ANNOUNCE as a read-writable bit. Also introduce the write 1 to > > > clear semantics for all read-writable bits of config status field. This could > > > help to reduce the config status field updating race between host and guest and > > > also simplify the implementation. > > > > > > Signed-off-by: Jason Wang > > > > This approach assumes an active config field, which neither lguest nor > > S/390 have. > > > > Thanks, > > Rusty. > > What does 'active' mean in this context? It means you are assuming that writes to the config field trap to the host. Rusty. -- How could I marry someone with more hair than me? http://baldalex.org