---
features:
  - |
    Some hypervisors add a signature to their guests, e.g. KVM is adding
    ``KVMKVMKVM\0\0\0``, Xen: ``XenVMMXenVMM``.
    The existence of a hypervisor signature enables some paravirtualization
    features on the guest as well as disallowing certain drivers which test
    for the hypervisor to load e.g. Nvidia driver [1]:
    "The latest Nvidia driver (337.88) specifically checks
    for KVM as the hypervisor and reports Code 43 for the
    driver in a Windows guest when found.  Removing or
    changing the KVM signature is sufficient for the driver
    to load and work."

    The new ``img_hide_hypervisor_id`` image metadata property hides the
    hypervisor signature for the guest.

    Currently only the libvirt compute driver can hide hypervisor signature
    for the guest host.

    To verify if hiding hypervisor id is working on Linux based system::

      $ cpuid | grep -i hypervisor_id

    The result should not be (for KVM hypervisor)::

      $ hypervisor_id = KVMKVMKVM\0\0\0

    You can enable this feature by setting the ``img_hide_hypervisor_id=true``
    property in a Glance image.

    [1]: http://git.qemu.org/?p=qemu.git;a=commitdiff;h=f522d2a
