On Mon, Aug 29, 2016 at 09:42:17PM -0400, Brandon Golway wrote:
(Copied from my post on the Arch Linux forums: https://bbs.archlinux.org/viewtopic.php?pid=1650650#p1650650) I have a FreeNAS 10 KVM setup via libvirt on my Arch server and I'd like to be able to test out the virtualization features in the nightly FreeNAS 10 builds but the problem is that I can't seem to get VT-x to correctly pass through to the guest. I have followed the [u][url= https://wiki.archlinux.org/index.php/KVM#Nested_virtualization]Nested Virtualization[/url][/u] section of the KVM wiki and I'm sure it's supported and enabled. Here's proof [code] [bran@nas ~]$ sudo systool -m kvm_intel -v | grep nested nested = "Y" [bran@nas ~]$ lscpu|grep Virtualization Virtualization: VT-x[/code] So the host/hardware isn't the problem, I believe the problem lies within libvirt. RedHat says to use [b]copy host CPU configuration[/b] or [b]host-passthrough[/b], with the latter being preferred. If I use the former I get the [b]CMT not supported[/b] error, but if I type in [b]host-passthrough[/b] which according to [u][url= https://bbs.archlinux.org/viewtopic.php?id=214539]this post[/url][/u] should work. When I set [b]host-passthrough[/b] it allows the system to boot up, but when I try to start a guest FreeNAS gives me the error that VT-x instructions aren't available, I have no idea how to check them either since the [b]proc[/b] pseudo-filesystem doesn't exist in BSD. I know for a fact that this isn't a problem with the FreeNAS builds because I've been testing them out for months on my Windows 10 desktop via VMware and nested virtualization works without issue, so it must be an issue with KVM/libvirt. 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.
<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. 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. Hope that helps, Martin
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