[fedora-virt] Nested KVM help

[James Slagle]

On Mon, Aug 19, 2013 at 01:25:29PM -0400, Cole Robinson wrote:
> On 08/19/2013 12:43 PM, James Slagle wrote:
> > Hi,
> > 
> > When I try to use nested KVM with Fedora 19, I'm experiencing a hang of the L1
> > vm.  I eventually have to do a "Force Off" from virt-manager on L0 since the L1
> > vm is completely unresponsive.
> > 
> > Both my L0 and L1 are F19, x86_64.  L2 doesn't really seem to matter as I can't
> > even get the guest to start before L1 completely locks up.  Even just
> > attempting to define a L2 guest that uses kvm virtualization locks up L1
> > completely.
> > 
> > Here are some more details.
> > 
> > On L0 (i've rebooted L0 after enabling the nested parameter):
> > [root at dublin ~]# uname -a
> > Linux dublin 3.10.7-200.fc19.x86_64 #1 SMP Thu Aug 15 23:19:45 UTC 2013 x86_64
> > x86_64 x86_64 GNU/Linux
> > [root at dublin ~]# cat /sys/module/kvm_intel/parameters/nested 
> > Y
> > [root at dublin ~]# rpm -q libvirt
> > libvirt-1.0.5.5-1.fc19.x86_64
> > [root at dublin ~]# lsmod | grep kvm
> > kvm_intel             138528  3 
> > kvm                   422809  1 kvm_intel
> > 
> > cpu section of libvirt xml for L1 vm:
> >   <cpu mode='custom' match='exact'>
> >     <model fallback='allow'>Nehalem</model>
> >     <feature policy='require' name='vmx'/>
> >   </cpu>
> > 
> > 
> > On L1:
> > [root at localhost jslagle]# uname -a
> > Linux localhost.localdomain 3.10.7-200.fc19.x86_64 #1 SMP Thu Aug 15 23:19:45
> > UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
> > [root at localhost jslagle]# rpm -q libvirt
> > libvirt-1.0.5.5-1.fc19.x86_64
> > [root at localhost jslagle]# lsmod | grep kvm
> > kvm_intel             138528  0 
> > kvm                   422809  1 kvm_intel
> > 
> > 
> > I've looked in dmesg output, /var/log/messages, and libvirt logs on both L0 and
> > L1 and can't see any errors.
> > 
> > Any ideas on how to debug this further?
> > Let me know if should file a bugzilla, I wasn't sure I had enough to go on to
> > go ahead and do that yet.
> > 
> 
> Unfortunately doesn't sound like there is much to go on, maybe the kvm
> maintainers can give some hints. Please file a bug against the kernel and CC me.

Filed: https://bugzilla.redhat.com/show_bug.cgi?id=998713

FWIW, I completely reinstalled L0, applied all updates, set things up in a
similar fashion, and still get the same issue.

--
-- James Slagle
--