Hyper-V 'elightment'?!

When

Hyper-V enlightment

is enabled (whatever it is?) in the advanced config of a kvm guest libvirt logs show an error as follows and VM hangs on boot:

# tail /var/log/libvirt/libvirtd.log
...
x86FeatureInData:780 : internal error: unknown CPU feature __kvm_hv_spinlocks

Should be named ‘enlightenment’ btw., shouldn’t it?

…when creating the guest VM with “virt-manager” no problems arise.

(Is using “virt-manager” a good thing at all?)

Are you enabling this on a Windows-VM?

/KNEBB

Yes, indeed. I just experienced this during the installation process of “Windows Server 2016 Standard Evaluation” on a HP DL380 with two CPU sockets / Intel Xeon.

Linux based VMs are not affected (of course).