From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:54079)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1Un8vN-0003TA-9Q
	for qemu-devel@nongnu.org; Thu, 13 Jun 2013 10:54:56 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1Un8vL-0002wc-Hm
	for qemu-devel@nongnu.org; Thu, 13 Jun 2013 10:54:53 -0400
Received: from mail-qc0-x22c.google.com ([2607:f8b0:400d:c01::22c]:59093)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1Un8vL-0002wK-Cb
	for qemu-devel@nongnu.org; Thu, 13 Jun 2013 10:54:51 -0400
Received: by mail-qc0-f172.google.com with SMTP id j10so5880294qcx.17
	for <qemu-devel@nongnu.org>; Thu, 13 Jun 2013 07:54:50 -0700 (PDT)
Sender: Paolo Bonzini <paolo.bonzini@gmail.com>
Message-ID: <51B9DD36.6080000@redhat.com>
Date: Thu, 13 Jun 2013 10:54:46 -0400
From: Paolo Bonzini <pbonzini@redhat.com>
MIME-Version: 1.0
References: <EE92950F97EE42469CA4F508D4691F5E016FAD15@SHSMSX104.ccr.corp.intel.com>
	<alpine.DEB.2.02.1306071246270.4589@kaball.uk.xensource.com>
	<51B1FF50.90406@eu.citrix.com>
	<alpine.DEB.2.02.1306071655060.4589@kaball.uk.xensource.com>
	<403610A45A2B5242BD291EDAE8B37D3010E56731@SHSMSX102.ccr.corp.intel.com>
	<CAFLBxZZfH8im-hTrma29Ag7CUR1HZEm=4b7ft_h5weukGL1BzQ@mail.gmail.com>
	<alpine.DEB.2.02.1306111735590.4548@kaball.uk.xensource.com>
	<51B83E7A02000078000DD6E9@nat28.tlf.novell.com>
	<51B847E3.5010604@eu.citrix.com>
	<alpine.DEB.2.02.1306131355550.4548@kaball.uk.xensource.com>
	<51B9CF26.1080707@eu.citrix.com>
In-Reply-To: <51B9CF26.1080707@eu.citrix.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [Xen-devel] [BUG 1747]Guest could't find bootable
 device with memory more than 3600M
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: George Dunlap <george.dunlap@eu.citrix.com>
Cc: Yongjie Ren <yongjie.ren@intel.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, Keir Fraser <keir@xen.org>, Ian Campbell <Ian.Campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Xudong Hao <xudong.hao@intel.com>, hanweidong@huawei.com, Tim Deegan <tim@xen.org>, qemu-devel@nongnu.org, yanqiangjun@huawei.com, wangzhenguo@huawei.com, xiaowei.yang@huawei.com, arei.gonglei@huawei.com, Jan Beulich <JBeulich@suse.com>, luonengjun@huawei.com, YongweiX Xu <yongweix.xu@intel.com>, SongtaoX Liu <songtaox.liu@intel.com>

Il 13/06/2013 09:54, George Dunlap ha scritto:
> 
> Also, as I understand it, at the moment:
> 1. Some operating systems (32-bit XP) won't be able to use relocated
> devices
> 2. Some devices (without 64-bit BARs) can't be relocated

Are there really devices with huge 32-bit BARs?  I think #1 is the only
real problem, so far though it never was for KVM.

SeaBIOS sorts the BARs from smallest to largest alignment, and then from
smallest to largest size.  Typically only the GPU will be relocated.

Paolo

> 3. qemu-traditional is fine with a resized <4GiB MMIO hole.
> 
> So if we have #1 or #2, at the moment an option for a work-around is to
> use qemu-traditional.
> 
> However, if we add your "print an error if the device doesn't fit", then
> this option will go away -- this will be a regression in functionality
> from 4.2.
> 
> I thought that what we had proposed was to have an option in xenstore,
> that libxl would set, which would instruct hvmloader whether to expand
> the MMIO hole and whether to relocate devices above 64-bit?