From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: [PATCH ARM v8 2/4] mini-os: arm: interrupt
 controller
Date: Tue, 21 Oct 2014 20:18:45 +0100
Message-ID: <1413919125.20604.40.camel@citrix.com>
References: <1412328051-20015-1-git-send-email-talex5@gmail.com>
	<1412328051-20015-3-git-send-email-talex5@gmail.com>
	<1413889218.23337.24.camel@citrix.com> <54466D06.5070000@linaro.org>
	<1413904601.23337.50.camel@citrix.com> <54467A40.4090201@linaro.org>
	<1413905722.23337.55.camel@citrix.com> <544683CD.40307@linaro.org>
	<13402DD8-D998-4D36-8FA2-C5D262E4900B@recoil.org>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
Received: from mail6.bemta14.messagelabs.com ([193.109.254.103])
	by lists.xen.org with esmtp (Exim 4.72)
	(envelope-from <Ian.Campbell@citrix.com>) id 1XgexN-0005bO-0A
	for xen-devel@lists.xenproject.org; Tue, 21 Oct 2014 19:18:57 +0000
In-Reply-To: <13402DD8-D998-4D36-8FA2-C5D262E4900B@recoil.org>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Anil Madhavapeddy <anil@recoil.org>
Cc: Thomas Leonard <talex5@gmail.com>, Dave.Scott@eu.citrix.com, stefano.stabellini@eu.citrix.com, Julien Grall <julien.grall@linaro.org>, samuel.thibault@ens-lyon.org, xen-devel@lists.xenproject.org
List-Id: xen-devel@lists.xenproject.org

On Tue, 2014-10-21 at 19:14 +0100, Anil Madhavapeddy wrote:
> On 21 Oct 2014, at 17:03, Julien Grall <julien.grall@linaro.org> wrote:
> > 
> >>> In this case, it would make mini-os working directly on Xen 4.4.
> > 
> >> and how long should mini-os carry this hack for then?
> > 
> > The current issue could be considered as an hardware bug (even though
> > it's an emulation). Time to time guest has to deal with hardware bug. As
> > long as it's very simple to fix it and doesn't impact performance, I
> > guess it's better to have it forever.
> > In this case, interrupts will be configured only once during mini-os
> > initialization.
> > 
> > If nobody care about running mini-os on current version of current Xen
> > 4.4.x, then fine.

Anybody who cares should fix the bug in Xen.  It would have taken less
typing than this thread.

> Isn't this what XEN_INTERFACE_VERSION checks are for?  It's certainly
> convenient to have MiniOS support the last stable version of the Xen
> ABI unless it's a huge diff, and this should just be a localised #ifdef.

This isn't an ABI issue, it's a violation of a hardware spec which we
are supposed to be emulating.

In any case XEN_INTERFACE_VERSION is for API compatiblity (for users of
the Xen headers), not ABI compatibility.

Ian.