From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:52135)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <akrowiak@linux.vnet.ibm.com>) id 1Ycx3A-0007Dy-Hs
	for qemu-devel@nongnu.org; Tue, 31 Mar 2015 10:21:56 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <akrowiak@linux.vnet.ibm.com>) id 1Ycx36-0001z3-D4
	for qemu-devel@nongnu.org; Tue, 31 Mar 2015 10:21:52 -0400
Received: from e33.co.us.ibm.com ([32.97.110.151]:48584)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <akrowiak@linux.vnet.ibm.com>) id 1Ycx36-0001yq-5n
	for qemu-devel@nongnu.org; Tue, 31 Mar 2015 10:21:48 -0400
Received: from /spool/local
	by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only!
	Violators will be prosecuted
	for <qemu-devel@nongnu.org> from <akrowiak@linux.vnet.ibm.com>;
	Tue, 31 Mar 2015 08:21:45 -0600
Received: from b03cxnp08028.gho.boulder.ibm.com
	(b03cxnp08028.gho.boulder.ibm.com [9.17.130.20])
	by d03dlp03.boulder.ibm.com (Postfix) with ESMTP id 2818E19D8042
	for <qemu-devel@nongnu.org>; Tue, 31 Mar 2015 08:12:49 -0600 (MDT)
Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167])
	by b03cxnp08028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with
	ESMTP id t2VELVNW38666284
	for <qemu-devel@nongnu.org>; Tue, 31 Mar 2015 07:21:31 -0700
Received: from d03av01.boulder.ibm.com (localhost [127.0.0.1])
	by d03av01.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP
	id t2VELg4g013502
	for <qemu-devel@nongnu.org>; Tue, 31 Mar 2015 08:21:42 -0600
Message-ID: <551AAD75.8090909@linux.vnet.ibm.com>
Date: Tue, 31 Mar 2015 10:21:41 -0400
From: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
MIME-Version: 1.0
Content-Type: multipart/alternative;
	boundary="------------080104070501050008090503"
Subject: [Qemu-devel] [qemu devel] disable shared memory is not available
 with this QEMU binary
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: qemu-devel@nongnu.org
Cc: marcel.apfelbaum@gmail.com

This is a multi-part message in MIME format.
--------------080104070501050008090503
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit

Commit 49d2e648e8087d154d8bf8b91f27c8e05e79d5a6 removed the QemuOptDesc 
elements from the
*desc* field of the *qemu_machine_opts *array defined in vl.c.  Since 
applying that patch to qemu
on my system, I can not start a guest from libvirt when certain machine 
options are configured
for the guest domain.  For example, if I configure the following for my 
guest domain:

     <memoryBacking>
         ...
         <nosharepages>
         ...
     </memoryBacking>

I get the following libvirt error when I try to start the guest:

     error: unsupported configuration: disable shared memory is not 
available with this QEMU binary

The *nosharepages *element generates the *-machine* option 
*mem-merge=off* on the QEMU command line.  The error is
thrown by libvirt because the QMP *query-command-line-options* command 
does not return *mem-merge* in the machine
options parameter list.  In fact, if I issue the 
*query-command-line-options* command via virsh as follows:

     virsh qemu-monitor-command guest_c2aa '{ "execute": 
"query-command-line-options", "arguments": { "option": "machine" } }'

No machine option parameters are returned:

{"return":[{"parameters":[],"option":"machine"}],"id":"libvirt-11"}


I took a look at the *qmp_query_command_line_options* function in 
*util/qemu-config.c*.  The function derives the
option parameters to return with the the query response from the 
QemuOptDesc elements contained in the
*desc* field of the *qemu_machine_opts *array defined in vl.c.  It 
appears that removing the
QemuOptDesc elements broke the *qmp_query_command_line_options* 
function.  If I restore the QemuOptDesc
elements removed by commit 49d2e648e8087d154d8bf8b91f27c8e05e79d5a6, I 
can start the guest with
*nosharepages* configured.

It would appear that a bug was introduced with commit 
49d2e648e8087d154d8bf8b91f27c8e05e79d5a6,
what say you?

--------------080104070501050008090503
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: 8bit

<html>
  <head>

    <meta http-equiv="content-type" content="text/html; charset=utf-8">
  </head>
  <body bgcolor="#FFFFFF" text="#000000">
    <font size="+1">Commit 49d2e648e8087d154d8bf8b91f27c8e05e79d5a6
      removed the QemuOptDesc elements from the<br>
      <b>desc</b> field of the <b>qemu_machine_opts </b>array defined
      in vl.c.  Since applying that patch to qemu <br>
      on my system, I can not start a guest from libvirt when certain
      machine options are configured <br>
      for the guest domain.  For example, if I configure the following
      for my guest domain:<br>
      <br>
          &lt;memoryBacking&gt;<br>
              ...<br>
              &lt;nosharepages&gt;<br>
              ...<br>
          &lt;/memoryBacking&gt;<br>
      <br>
      I get the following libvirt error when I try to start the guest:<br>
          </font><br>
        error: unsupported configuration: disable shared memory is not
    available with this QEMU binary<br>
    <br>
    The <b>nosharepages </b>element generates the <b>-machine</b>
    option <b>mem-merge=off</b> on the QEMU command line.  The error is
    <br>
    thrown by libvirt because the QMP <b>query-command-line-options</b>
    command does not return <b>mem-merge</b> in the machine <br>
    options parameter list.  In fact, if I issue the <b>query-command-line-options</b>
    command via virsh as follows:<br>
    <br>
        virsh qemu-monitor-command guest_c2aa '{ "execute":
    "query-command-line-options", "arguments": { "option":        
    "machine" } }'<br>
    <br>
    No machine option parameters are returned:<br>
    <br>
    <font size="+1">   
      {"return":[{"parameters":[],"option":"machine"}],"id":"libvirt-11"}</font><br>
    <br>
    <br>
    I took a look at the <b>qmp_query_command_line_options</b> function
    in <b>util/qemu-config.c</b>.  The function derives the<br>
    option parameters to return with the the query response from the <font
      size="+1">QemuOptDesc elements contained in the<br>
    </font><b>desc</b> field of the <font size="+1"><b>qemu_machine_opts
      </b>array defined in vl.c.  It appears that removing the </font><br>
    <font size="+1">QemuOptDesc elements broke the </font><b>qmp_query_command_line_options</b>
    function.  If I restore the <font size="+1">QemuOptDesc <br>
      elements</font> removed by commit <font size="+1">49d2e648e8087d154d8bf8b91f27c8e05e79d5a6,
      I can start the guest with <br>
      <b>nosharepages</b> configured.<br>
      <br>
      It would appear that a bug was introduced with </font>commit <font
      size="+1">49d2e648e8087d154d8bf8b91f27c8e05e79d5a6,<br>
      what say you?<br>
    </font>
  </body>
</html>

--------------080104070501050008090503--