kvm-hint-dedicated requires host CPU passthrough?

Hi, libvirt refuses to set KVM_HINTS_DEDICATED when the CPU model is not host-passthrough. Is there a reason for this limitation? My understanding is that KVM_HINTS_DEDICATED means the vCPU is pinned to a host CPU that is not shared with other tasks. Any KVM vCPU should be able to support this feature, regardless of whether host-passthrough is used or not. Stefan