Long-time Xen HVM and Xen PV users are missing /sys/hypervisor entries when moving to KVM. One report is about getting the VM UUID. The VM UUID can already be retrieved using /sys/devices/virtual/dmi/id/product_uuid. This has two downsides: (1) it requires root privileges and (2) it is only available on KVM and Xen HVM. By exposing /sys/hypervisor/uuid when running on KVM as well, we provide an interface that's functional for KVM, Xen HVM, and Xen PV. Let's do so by providing arch-specific hooks so that different architectures can implement the hooks in different ways. Further work can be done by consolidating the creation of the basic /sys/hypervisor across hypervisors. Filippo Sironi (2): KVM: Start populating /sys/hypervisor with KVM entries KVM: x86: Implement the arch-specific hook to report the VM UUID