[Qemu-devel] [PATCH v2 0/2] intel_iommu: Add support for translation for devices behind bridges

[Knut Omang <knut.omang@oracle.com>]

This patch set changes the data structure used to handle address spaces within
the emulated Intel iommu to support traversal also if bus numbers are dynamically
allocated, as is the case for devices that sit behind root ports or downstream switches.
This means that we cannot use bus number as index, instead a QLIST is used.

This requires a change in the API for setup of IOMMUs which is taken care of by
the first patch. The second patch implements the fix.

The initial patch set had some discussion related to whether this fix, applied to the
bridge code, was applicable to all bridges. No clear conclusion arised as far as I understood,
in the meantime a number of people have run into the same issue as I did which lead me
to implement this, so I gather it might be a useful intermediate solution that works until
a better approach can be found? I believe the IOMMU emulation code has limited usefulness
if it only supports devices sitting directly on the root complex.

This is the thread following the initial patch set:

  http://thread.gmane.org/gmane.comp.emulators.qemu/302246

The patch set was also discussed in this thread:

  http://thread.gmane.org/gmane.comp.emulators.qemu/316949

Changes from v1:
  - Rebased to current master
  - Fixed minor syntax issues

Knut Omang (2):
  iommu: Replace bus+devfn arguments with PCIDevice* in PCIIOMMUFunc
  intel_iommu: Add support for translation for devices behind bridges.

 hw/alpha/typhoon.c            |  2 +-
 hw/i386/intel_iommu.c         | 56 +++++++++++++++++++------------------------
 hw/pci-host/apb.c             |  2 +-
 hw/pci-host/prep.c            |  3 +--
 hw/pci-host/q35.c             | 42 +++++++++++++-------------------
 hw/pci/pci.c                  |  7 +++---
 hw/pci/pci_bridge.c           |  6 +++++
 hw/ppc/spapr_pci.c            |  2 +-
 include/hw/i386/intel_iommu.h |  6 +++--
 include/hw/pci/pci.h          |  5 +++-
 10 files changed, 62 insertions(+), 69 deletions(-)

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2.4.3