feat: nested virtualization support per guest on the same kvm host

[lukasmrtvy]

ISSUE TYPE

• Feature Idea

DESCRIPTION

As a CS user, I would like to be able to create a Guest / VM with guest.cpu.mode=host-passtrough and also a second VM without guest.cpu.mode passtrough on the same KVM host, that's not possible, because guest.cpu.mode is applied to the KVM host globally.

PROPOSAL

Custom compute offering large.metal ( similar to flavors in AWS with nested virtualization capability ) when one can set allow.additional.vm.configuration.list.kvm ( https://www.shapeblue.com/cloudstack-feature-first-look-enable-sending-of-arbitrary-configuration-data-to-vms/ ), probably doable with <cpu mode='host-passthrough' migratable='off'></cpu> XML snippet ( see for more info https://libvirt.org/formatdomain.html#cpu-model-and-topology ) or with simple tick-checkbox for enabling nested virtualization.

It's important to have this ability directly on the offering to support for example CloudStack CAPI implementation, here https://github.com/kubernetes-sigs/cluster-api-provider-cloudstack/blob/main/templates/cluster-template.yaml#L72