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[Ludovic Beliveau <ludovic.beliveau@xxxxxxxxxxxxx>]

Public bug reported:

Issue has been reproduced in kilo.

There is a limitation when using VFIO with some PCI devices.  Some PCI
devices with multiple hardware components are places in the same IOMMU
group (for example a NIC with multiple ports).  In this case, the
multiple PCI devices in that same IOMMU group can't be assigned to
multiple guests, they are limited to be used by only one guest.

It is possible to specify the driver name when generating the libvirt
XML for a guest (name can be "vfio" or "kvm" for legacy PCI device
assignment method).

The proposed solution is to provide a configuration parameter to specify
which driver to use when using PCI passthrough devices.  Perhaps this
can be specified by hardware model (PCI vendor and product).

The issue was also described here:
https://ask.openstack.org/en/question/62749/vfio-pci-vs-pci-assign-for-
sr-iov-direct-ports/

** Affects: nova
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1498684

Title:
  Fail to use SR-IOV ports when VFIO is loaded

Status in OpenStack Compute (nova):
  New

Bug description:
  Issue has been reproduced in kilo.

  There is a limitation when using VFIO with some PCI devices.  Some PCI
  devices with multiple hardware components are places in the same IOMMU
  group (for example a NIC with multiple ports).  In this case, the
  multiple PCI devices in that same IOMMU group can't be assigned to
  multiple guests, they are limited to be used by only one guest.

  It is possible to specify the driver name when generating the libvirt
  XML for a guest (name can be "vfio" or "kvm" for legacy PCI device
  assignment method).

  The proposed solution is to provide a configuration parameter to
  specify which driver to use when using PCI passthrough devices.
  Perhaps this can be specified by hardware model (PCI vendor and
  product).

  The issue was also described here:
  https://ask.openstack.org/en/question/62749/vfio-pci-vs-pci-assign-
  for-sr-iov-direct-ports/

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