hide_hypervisor_id doesn't hide hyperv signature for Windows VMs

[Konstantinos Samaras-Tsakiris]

Blueprints hide-hypervisor-id-flavor-extra-spec and add-kvm-hidden-feature allow hiding KVM's signature for guests, which is necessary for Nvidia drivers to work in VMs with passthrough GPUs.
While this works well for linux guests on KVM hypervisors, it doesn't work for Windows guests on KVM. For them, KVM emulates some HyperV features. With the current implementation, KVM's signature is hidden, but HyperV's is not, and Nvidia drivers don't work in Windows VMs.

I propose generating an extra tag in the libvirt xml for Windows guests on KVM which obfuscates HyperV's signature too, controlled by the existing image and flavor parameters (img_hide_hypervisor_id and hide_hypervisor_id correspondingly).

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/579897

[Maciej Jozefczyk (maciejjozefczyk)]

I can confirm that bug, and the presented solution looks reasonable.

[melanie witt (melwitt)]

This looks like an enhancement to the existing hiding hypervisor id code, rather than a defect in the existing support. As such, I'm setting this as a Wishlist bug.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/579897
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=ca543438e183b2bd97a08ef781ddeab8303354ed
Submitter: Zuul
Branch: master

commit ca543438e183b2bd97a08ef781ddeab8303354ed
Author: Konstantinos Samaras-Tsakiris <email address hidden>
Date: Tue Jul 3 12:28:55 2018 +0000

    Hide hypervisor id on windows guests

    Blueprints hide-hypervisor-id-flavor-extra-spec [1] and
    add-kvm-hidden-feature [2] allow hiding KVM's signature for guests,
    which is necessary for Nvidia drivers to work in VMs with passthrough
    GPUs. While this works well for linux guests on KVM, it doesn't work
    for Windows guests.

    For them, KVM emulates some HyperV features. With the
    current implementation, KVM's signature is hidden, but HyperV's is not,
    and Nvidia drivers don't work in Windows VMs.

    This change generates an extra element in the libvirt xml for Windows
    guests on KVM which obfuscates HyperV's signature too, controlled by the
    existing image and flavor parameters (img_hide_hypervisor_id and
    hide_hypervisor_id correspondingly). The extra xml element is
      <vendor_id state='on' value='1234567890ab'/>
    in features/hyperv.

    [1] https://blueprints.launchpad.net/nova/+spec/hide-hypervisor-id-flavor-extra-spec
    [2] https://blueprints.launchpad.net/nova/+spec/add-kvm-hidden-feature

    Change-Id: Iaaeae9281301f14f4ae9b43f4a06de58b699fd68
    Closes-Bug: 1779845

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/stein
Review: https://review.opendev.org/663616

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 20.0.0.0rc1 release candidate.

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Elod Illes <email address hidden>" on branch: stable/stein
Review: https://review.opendev.org/c/openstack/nova/+/663616
Reason: This branch transitioned to End of Life for this project, open patches needs to be closed to be able to delete the branch.