From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:51969)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <imammedo@redhat.com>) id 1YiNqZ-0000yM-VE
	for qemu-devel@nongnu.org; Wed, 15 Apr 2015 09:59:20 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <imammedo@redhat.com>) id 1YiNqU-00089L-Tj
	for qemu-devel@nongnu.org; Wed, 15 Apr 2015 09:59:19 -0400
Received: from mx1.redhat.com ([209.132.183.28]:53809)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <imammedo@redhat.com>) id 1YiNqU-00089B-Lv
	for qemu-devel@nongnu.org; Wed, 15 Apr 2015 09:59:14 -0400
Received: from int-mx10.intmail.prod.int.phx2.redhat.com
	(int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23])
	by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t3FDxDiI029104
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256
	verify=FAIL)
	for <qemu-devel@nongnu.org>; Wed, 15 Apr 2015 09:59:14 -0400
Date: Wed, 15 Apr 2015 15:59:09 +0200
From: Igor Mammedov <imammedo@redhat.com>
Message-ID: <20150415155909.5eb62abc@nial.brq.redhat.com>
In-Reply-To: <20150415122851-mutt-send-email-mst@redhat.com>
References: <1425399495-13664-1-git-send-email-imammedo@redhat.com>
	<20150415122851-mutt-send-email-mst@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH V14 0/3] Virtual Machine Generation ID
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: "Michael S. Tsirkin" <mst@redhat.com>
Cc: ghammer@redhat.com, Yan Vugenfirer <yvugenfi@redhat.com>, qemu-devel@nongnu.org

On Wed, 15 Apr 2015 12:38:57 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Tue, Mar 03, 2015 at 05:18:12PM +0100, Igor Mammedov wrote:
> > Changes since v13:
> >  * fix comment style to /*... */ in testcase
> >  * make BAR TARGET_PAGE_SIZE as required by spec
> >  * make BAR prefetchable, spec also says that it shouldn't be
> >    marked as non cached
> >  * ACPI part
> >     * merge separate VGID device with PCI device description
> >     * mark device as not shown in UI,
> >       it hides "VM Generation ID" device from device manager
> >       and leaves only "PCI Standard RAM Controller" device there
> 
> In an offline chat, Yan (Cc) mentioned that with windows guests,
> PCI rebalancing can move BAR values around.
> Yan, could you comment on-list please?
> Is there a way to force this, for testing?
> 
> ACPI spec mentions this:
> If a platform uses a PCI BAR Target operation region, an ACPI OS will
> not load a native device driver for the associated PCI function. For
> example, if any of the BARs in a PCI function are associated with a PCI
> BAR Target operation region, then the OS will assume that the PCI
> function is to be entirely under the control of the ACPI BIOS. No driver
> will be loaded. Thus, a PCI function can be used as a platform
> controller for some task (hot-plug PCI, and so on) that the ACPI BIOS
> performs.
It seems that WS2012R2 doesn't honor this part of spec,
it still tries to find matching driver and load it.

> 
> This might also avoid driver prompt from windows?
it isn't.