Support CPU hotplug for VMs with Virtual Topologies

[rsmontero]

Description VMs with a virtual CPU topology (not pinned) should be able to be live-resized (VCPU_MAX) parameter. This requires to properly compute the topology based on the current CPU value as well as adding the hotplugable attribute in the libvirt definition.

It may also require some support from context (udev rules).

Use case Resize VMs with virtual topolgies (not pinned)

Interface Changes NONE

Additional Context Lots of details about the implementation can be found in #5293

Progress Status

• [ ] Branch created
• [ ] Code committed to development branch
• [ ] Testing - QA
• [ ] Documentation
• [ ] Release notes - resolved issues, compatibility, known issues
• [ ] Code committed to upstream release/hotfix branches
• [ ] Documentation committed to upstream release/hotfix branches

[kvakanet]

Hello! I maybe found problem. CPU hotplug work up and down if VM running and up vcpu to vcpu_max and down vcpu to start value vcpu. Example: VCPU_MAX=5 and start VCPU=2 increase to VCPU=4 and poweroff VM. Poweron VM and VCPU_MAX=5 and start VCPU=4 and hotplug(onlne) decrease VCPU before VCPU=3 not work. (checked on opennebula 6.4 CE)

Sorry for bad english.