From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: Re: VIRTIO - compatibility with different virtualization solutions Date: Tue, 25 Feb 2014 11:03:24 +1030 Message-ID: <87y51058vf.fsf__8294.64352359555$1393292385$gmane$org@rustcorp.com.au> References: <20140217132331.GA3441@olila.local.net-space.pl> <87vbwcaqxe.fsf@rustcorp.com.au> <87ha7ubme0.fsf@rustcorp.com.au> <20140221100506.GR18398@zion.uk.xensource.com> <20140221150107.GG15905@phenom.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WI6xv-0002Tp-E7 for xen-devel@lists.xenproject.org; Tue, 25 Feb 2014 01:37:47 +0000 Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 25 Feb 2014 11:37:40 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 404E0357805B for ; Tue, 25 Feb 2014 12:37:38 +1100 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s1P1HsqZ8978830 for ; Tue, 25 Feb 2014 12:17:54 +1100 Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s1P1baj2010093 for ; Tue, 25 Feb 2014 12:37:37 +1100 In-Reply-To: <20140221150107.GG15905@phenom.dumpdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Konrad Rzeszutek Wilk , Wei Liu Cc: virtio-dev@lists.oasis-open.org, Ian Campbell , Stefano Stabellini , Daniel Kiper , ian@bromium.com, Anthony Liguori , sasha.levin@oracle.com, xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org Konrad Rzeszutek Wilk writes: > On Fri, Feb 21, 2014 at 10:05:06AM +0000, Wei Liu wrote: >> On Thu, Feb 20, 2014 at 06:50:59PM -0800, Anthony Liguori wrote: >> > The standard should say, "physical address" > > This conversation is heading towards - implementation needs it - hence lets > make the design have it. Which I am OK with - but if we are going that > route we might as well call this thing 'my-pony-number' because I think > each hypervisor will have a different view of it. > > Some of them might use a physical address with some flag bits on it. > Some might use just physical address. > > And some might want an 32-bit value that has no correlation to to physical > nor virtual addresses. True, but if the standard doesn't define what it is, it's not a standard worth anything. Xen is special because it's already requiring guest changes; it's a platform in itself and so can be different from everything else. But it still needs to be defined. At the moment, anything but guest-phys would not be compliant. That's a Good Thing if we simply don't know the best answer for Xen; we'll adjust the standard when we do. Cheers, Rusty.