From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755085Ab1KIPck (ORCPT ); Wed, 9 Nov 2011 10:32:40 -0500 Received: from mx1.redhat.com ([209.132.183.28]:27440 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751370Ab1KIPcj (ORCPT ); Wed, 9 Nov 2011 10:32:39 -0500 Date: Wed, 9 Nov 2011 17:33:14 +0200 From: "Michael S. Tsirkin" To: Pekka Enberg Cc: Sasha Levin , Rusty Russell , lkml - Kernel Mailing List , Alexey Kardashevskiy , Amit Shah , Christian Borntraeger , Krishna Kumar , Pawel Moll , Wang Sheng-Hui , virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, avi@redhat.com, penberg@cs.helsinki.fi Subject: Re: [PATCH RFC] virtio-spec: flexible configuration layout Message-ID: <20111109153313.GB25329@redhat.com> References: <1320150813.3847.24.camel@lappy> <20111101124223.GA14060@redhat.com> <8739e7uy87.fsf@rustcorp.com.au> <20111102233110.GA20289@redhat.com> <20111108214021.GA4538@redhat.com> <1320828366.31056.16.camel@lappy> <20111109101318.GB20612@redhat.com> <1320841683.31056.41.camel@lappy> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 09, 2011 at 02:36:43PM +0200, Pekka Enberg wrote: > On Wed, 9 Nov 2011, Sasha Levin wrote: > >They don't exist in kernel code either, for same reason as above. > > > >Nothing will break if we remove it since no one really used it, we were > >probably the first and only implementation of the spec which considered > >them :) > > As long as we are able to run older versions of the KVM tool with > newer kernels and vice versa, I see no reason why we can't drop 64-bit > features from the KVM tool. > > Pekka What do these older versions do? Do they *set* bit 31 in the features register? -- MST