On 22/02/19 02:30, Sean Christopherson wrote: > if (kvm_advertise_kvm()) { > if (<handle kvm msr>) > return ...; > } else if (kvm_advertise_hyperv()) { > if (<handle hyperv msr>) > return ...; > } else if (kvm_advertise_xen()) { > if (<handle xen msrs>) > return ...; > } > > <fall through to main switch statement> > > Obviously assumes KVM only advertises itself as one hypervisor, and so > the ordering is arbitrary. No, KVM can advertise as both KVM and Hyper-V. CPUID 0x40000000 is used for Hyper-V, while 0x40000100 is used for KVM. The MSRs do not conflict. Paolo