[libvirt] Query regarding sharing of vcpu's (cpu alloc ratio 1.0) between VM's

HI, I have a Q about sharing a vcpu across Vm's (cpu alloc ratio 1.0 and HT not enabled)? I have a Use case where a VM needs vcpu's and one of the vcpu is dedicated to the VM for some traffic processing. We want the other vcpu which is used for control processing and can be shared with a similar VM's control processing. Is this possible and support in openstack/libvirt/KVM? If so could you please advice how to test it? Regards, Bharani..