Comment 19 for bug 1633120

Reviewed: https://review.openstack.org/635075
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=5c5a6b93a07b0b58f513396254049c17e2883894
Submitter: Zuul
Branch: stable/ocata

commit 5c5a6b93a07b0b58f513396254049c17e2883894
Author: Sean Mooney <email address hidden>
Date: Wed Dec 19 19:40:05 2018 +0000

    PCI: do not force remove allocated devices

    In the ocata release the pci_passthrough_whitelist
    was moved from the [DEFAULT] section of the nova.conf
    to the [pci] section and renamed to passthrough_whitelist.

    On upgrading if the operator chooses to migrate the config
    value to the new section it is not uncommon
    to forget to rename the config value.
    Similarly if an operator is updateing the whitelist and
    mistypes the value it can also lead to the whitelist
    being ignored.

    As a result of either error the nova compute agent
    would delete all database entries for a host regardless of
    if the pci device was in use by an instance. If this occurs
    the only recorse for an operator is to delete and recreate
    the guest on that host after correcting the error or manually
    restore the database to backup or otherwise consistent state.

    This change alters the _set_hvdevs function to not force
    remove allocated or claimed devices if they are no longer
    present in the pci whitelist.

    Conflicts:
      nova/pci/manager.py

    Closes-Bug: #1633120
    Change-Id: I6e871311a0fa10beaf601ca6912b4a33ba4094e0
    (cherry picked from commit 26c41eccade6412f61f9a8721d853b545061adcc)