Re: [libvirt-users] Help With Nested Virtualization
On Wed, Aug 31, 2016 at 12:48:33PM +0200, Martin Kletzander wrote:
On Mon, Aug 29, 2016 at 09:42:17PM -0400, Brandon Golway wrote:
> (Copied from my post on the Arch Linux forums:
[...]
> Can someone clue me in on what the issue is?
>
> Here's the entire XML config for the FreeNAS VM
>
> [code]<!--
> WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
> OVERWRITTEN AND LOST. Changes to this xml configuration should be made
> using:
> virsh edit FreeNAS_10
> or other application using the libvirt API.
> -->
>
Just as I see you grabbed it from the place where it is stored, you
should rather instead do 'virsh dumpxml FreeNAS_10', or remove the
comment above. Otherwise it steers other users to believing that
mangling with internal XML files is safe.
Yeah, or use the `virt-xml` tool (comes as part of `virt-install`
package). To pass-through host CPU to the level-1 guest:
$ virt-xml FreeNAS_10 --edit --cpu host-passthrough,clearxml=yes
If you issue this while the guest is running, it'll take affect on next
reboot.
> <domain type='kvm'>
> <name>FreeNAS_10</name>
> <uuid>ea816b85-7685-495a-bc97-28a882f190d7</uuid>
> <title>FreeNAS v10</title>
> <description>Nightly Alpha Test Releases</description>
> <memory unit='KiB'>6340608</memory>
> <currentMemory unit='KiB'>6340608</currentMemory>
> <vcpu placement='static'>4</vcpu>
> <os>
> <type arch='x86_64'
machine='pc-i440fx-2.6'>hvm</type>
> <bootmenu enable='no'/>
> </os>
> <features>
> <acpi/>
> <apic/>
> <vmport state='off'/>
> </features>
> <cpu mode='host-passthrough'/>
Although what you did should be enough for the nested virt to work, I
have just an idea to try out. I can't try it because I don't have
nested virt turned on for the module and don't want to reboot now.
Assuming you're talking about the physical host, you don't need a reboot
of the host :-) You can simply:
$ sudo rmmod kvm-intel
$ echo "options kvm-intel nested=y" > /etc/modprobe.d/dist.conf
$ sudo modprobe kvm-intel
But
if you have new enough libvirt, you should be able to do:
<cpu mode='host-passthrough'>
<feature policy='require' name='vmx'/>
</cpu>
Also check that you are not missing the kvm_intel module in the L1 guest
kernel and other similar non-nested troubleshooting steps as well.
Yeah. If the L1 guest has the /dev/kvm character device, then he's good:
$ file /dev/kvm
/dev/kvm: character special (10/232)
--
/kashyap