12.3. Restrictions and Limitations

  • It is strongly recommended to run Red Hat Enterprise Linux 7.2 or later in the L0 host and the L1 guests. L2 guests can contain any guest system supported by Red Hat.
  • It is not supported to migrate L1 or L2 guests.
  • Use of L2 guests as hypervisors and creating L3 guests is not supported.
  • Not all features available on the host are available to be utilized by the L1 hypervisor. For instance, IOMMU/VT-d or APICv cannot be used by the L1 hypervisor.
  • To use nested virtualization, the host CPU must have the necessary feature flags. To determine if the L0 and L1 hypervisors are set up correctly, use the cat /proc/cpuinfo command on both L0 and L1, and make sure that the following flags are listed for the respective CPUs on both hypervisors:
    • For Intel - vmx (Hardware Virtualization) and ept (Extended Page Tables)
    • For AMD - svm (equivalent to vmx) and npt (equivalent to ept)