Choose VM template from the UI and ask for 512 vcpus it gives me this in the VMI definition:
    cpu:
      cores: 1
      maxSockets: 512
      model: host-model
      sockets: 512
      threads: 1

The VM fails to boot with: 
{"component":"virt-launcher","level":"info","msg":"2025-07-29T20:31:00.197307Z qemu-kvm: -accel kvm: warning: Number of hotpluggable cpus requested (512) exceeds the recommended cpus supported by KVM (128)","subcomponent":"qemu","timestamp":"2025-07-29T20:31:00.895452Z"}

Same error for >=65 total vcpus.
65 vcpu VMI gets:
{"component":"virt-launcher","level":"info","msg":"2025-07-29T21:05:42.114289Z qemu-kvm: -accel kvm: warning: Number of hotpluggable cpus requested (260) exceeds the recommended cpus supported by KVM (128)","subcomponent":"qemu","timestamp":"2025-07-29T21:05:42.165383Z"}


With 64 vcpus the VMI gets:
    cpu:
      cores: 1
      maxSockets: 256
      model: host-model
      sockets: 64
      threads: 1
In this case the VM boots up. 

kubevirt-hyperconverged-operator.v4.19.1
OCP Version: 4.20.0-ec.4

every time

1. Create VM from template w/ 65+ vcpus

Fails

Should have been fixed with CNV-57352

Marking critical as this has been broken for a long time now.