https://www.theregister.co.uk/2018/06/15/xen_project_patches_intels_lazy_fpu_flaw/

The Xen Project has revealed that its hypervisor is susceptible to the Lazy FPU flaw found in Intel’s x86 CPUs.

An advisory says ‘Systems running all versions of Xen are affected”, provided they employ “Intel Core based processors (from at least Nehalem onwards)”.