From mboxrd@z Thu Jan  1 00:00:00 1970
From: Antoine Martin <antoine@nagafix.co.uk>
Subject: guest patched with pax causes "set_cr0: 0xffff88000[...] #GP, reserved
 bits 0x8004003?" flood on host
Date: Wed, 10 Mar 2010 23:17:24 +0700
Message-ID: <4B97C614.3030802@nagafix.co.uk>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
To: kvm@vger.kernel.org, Avi Kivity <avi@redhat.com>,
	pageexec@freemail.hu
Return-path: <kvm-owner@vger.kernel.org>
Received: from mamba.nagafix.co.uk ([194.145.196.68]:35400 "EHLO
	mail.nagafix.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org
	with ESMTP id S1750839Ab0CJQRe (ORCPT <rfc822;kvm@vger.kernel.org>);
	Wed, 10 Mar 2010 11:17:34 -0500
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

Hi,

I've updated my host kernel headers to 2.6.33, rebuilt glibc (and the 
base system), rebuilt kvm.
... and now I get hundreds of those in dmesg on the host when I start a 
guest kernel that worked fine before. (2.6.33 + pax patch v5)
  set_cr0: 0xffff88000ec29d58 #GP, reserved bits 0x80040033
  set_cr0: 0xffff88000f3cdb38 #GP, reserved bits 0x8004003b
  set_cr0: 0xffff88000f3dbc88 #GP, reserved bits 0x80040033
  set_cr0: 0xffff88000f83b958 #GP, reserved bits 0x8004003b
(hundreds of all 4)
And the VM just reboots shortly after starting init.
Funnily enough, I've got some VMs still running that kernel just fine! 
(as I started them before the headers+glibc+qemu-kvm rebuild)

Now, you might just say that I shouldn't use out of tree patches like 
pax, but I just want to know one thing: should the guest kernel still be 
able to flood dmesg on the host like this?

Thanks
Antoine

PS: Avi, are you still interested in seeing if this rebuild fixes the 
pread/glibc bug?