9.3. Central Processing Unit (CPU)
Each host within a cluster has a number of virtual CPUs (vCPUs). The virtual CPUs are in turn exposed to guests running on the hosts. All virtual CPUs exposed by hosts within a cluster are of the type selected when the cluster was initially created via Red Hat Virtualization Manager. Mixing of virtual CPU types within a cluster is not possible.
Each available virtual CPU type has characteristics based on physical CPUs of the same name. The virtual CPU is indistinguishable from the physical CPU to the guest operating system.
Support for x2APIC:
All virtual CPU models provided by Red Hat Enterprise Linux 7 hosts include support for x2APIC. This provides an Advanced Programmable Interrupt Controller (APIC) to better handle hardware interrupts.