Comment 8 for bug 1821938

Reviewed: https://review.openstack.org/649630
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=97a806b7900d9e55ad15c10184d2bd48f23efff0
Submitter: Zuul
Branch: stable/stein

commit 97a806b7900d9e55ad15c10184d2bd48f23efff0
Author: Sean Mooney <email address hidden>
Date: Tue Apr 2 18:27:24 2019 +0100

    Libvirt: gracefully handle non-nic VFs

    As part of adding support for bandwidth based scheduling
    I038867c4094d79ae4a20615ab9c9f9e38fcc2e0a introduced
    automatic discovery of parent netdev names for PCIe
    virtual functions.

    Nova's PCI passthrough support was originally developed for
    Intel QAT devices and other generic PCI devices. Later support
    for Neutron based SR-IOV NIC was added.

    The PCI-SIG SR-IOV specification while most often used by NIC
    vendors to virtualise a NIC in hardware was designed for devices
    of any PCIe class. Support for Intel's QAT device and other
    accelerators like AMD's SRIOV based vGPU have therefore been
    regressed by the introduction of the new parent_ifname lookup code.

    This change simply catches the exception that would be raised
    when pci_utils.get_ifname_by_pci_address is called on generic
    VFs allowing a graceful fallback to the previous behaviour.

    Change-Id: Ib3811f828246311d90b0e3ba71c162c03fb8fe5a
    Closes-Bug: #1821938
    (cherry picked from commit e7ae6c65cd24fb3e0776fac80fbab2ab16e9d9ed)