From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:36947)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1VGWmh-0005NQ-4w
	for qemu-devel@nongnu.org; Mon, 02 Sep 2013 12:15:30 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1VGWmb-0001Wd-67
	for qemu-devel@nongnu.org; Mon, 02 Sep 2013 12:15:23 -0400
Received: from mx1.redhat.com ([209.132.183.28]:61293)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1VGWma-0001WW-Ug
	for qemu-devel@nongnu.org; Mon, 02 Sep 2013 12:15:17 -0400
Date: Mon, 2 Sep 2013 19:17:13 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20130902161713.GA4971@redhat.com>
References: <1378131189-25538-1-git-send-email-marcel.a@redhat.com>
	<1378131189-25538-4-git-send-email-marcel.a@redhat.com>
	<CAFEAcA82ikF+rMJo0iFgDqpQMBGVri3UdkBEOm+zhiySM+B53Q@mail.gmail.com>
	<1378136553.2640.34.camel@localhost.localdomain>
	<CAFEAcA-xZqiFudd75qjdGz_RTD2jsOa-ei53BQYyXoiA_PC2RA@mail.gmail.com>
	<20130902160013.GC4691@redhat.com>
	<CAFEAcA-+V7VCNoXLVCMpBc3Y7TgLAkfZNdBPA55NV3ecA=-keQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAFEAcA-+V7VCNoXLVCMpBc3Y7TgLAkfZNdBPA55NV3ecA=-keQ@mail.gmail.com>
Subject: Re: [Qemu-devel] [PATCH RFC 3/3] hw/pci-host: catch acesses to
 unassigned pci addresses
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Anthony Liguori <aliguori@us.ibm.com>, QEMU Developers <qemu-devel@nongnu.org>, Andreas =?iso-8859-1?Q?F=E4rber?= <afaerber@suse.de>, Marcel Apfelbaum <marcel.a@redhat.com>

On Mon, Sep 02, 2013 at 05:05:10PM +0100, Peter Maydell wrote:
> On 2 September 2013 17:00, Michael S. Tsirkin <mst@redhat.com> wrote:
> > On Mon, Sep 02, 2013 at 04:53:50PM +0100, Peter Maydell wrote:
> >> at the moment what happens is that the pci controller
> >> creates the PCI memory and io memory regions (or cheats
> >> by reusing the system memory space[*]),
> 
> >> [*] I'm pretty sure this is a bug in all platforms that do it.
> 
> > Well as usual this cheat originated with PIIX.
> > AFAIK PIIX actually has a shared bus for memory and PCI
> > so this is not a bug there, I think.
> 
> It will be when you introduce this "return -1 for unassigned
> addresses", though, since you only want that to happen
> for PCI accesses, not system memory accesses, right?
> 
> thanks
> -- PMM

What happens with PIIX is that everything that is not
in system memory is PCI.
So there's no such thing as "unassigned system memory
address": all unassigned addresses are PCI addresses.

-- 
MST