It started right after I tried to run our OpenStack CI (so the nested operation) on Bionic (with OpenStack Queens). Previously I used Xenial (with kernel 4.4.0), that still works.
The host kernel is still from Xenial.
So:
Host with KVM->Guest with KVM->Nested Guest
Xenial (4.4) -> Bionic (4.15)-> any other - crash
Xenial (4.4) -> Xenial (4.4) -> any other - works
It started right after I tried to run our OpenStack CI (so the nested operation) on Bionic (with OpenStack Queens). Previously I used Xenial (with kernel 4.4.0), that still works.
The host kernel is still from Xenial.
So:
Host with KVM->Guest with KVM->Nested Guest
Xenial (4.4) -> Bionic (4.15)-> any other - crash
Xenial (4.4) -> Xenial (4.4) -> any other - works