[PATCH kernel 0/5] powerpc/powenv/ioda: Allow huge DMA window at 4GB

[Alexey Kardashevskiy]

Here is an attempt to support bigger DMA space for devices
supporting DMA masks less than 59 bits (GPUs come into mind
first). POWER9 PHBs have an option to map 2 windows at 0
and select a windows based on DMA address being below or above
4GB.

This adds the "iommu=iommu_bypass" kernel parameter and
supports VFIO+pseries machine - current this requires telling
upstream+unmodified QEMU about this via
-global spapr-pci-host-bridge.dma64_win_addr=0x100000000
or per-phb property. 4/4 advertises the new option but
there is no automation around it in QEMU (should it be?).

For now it is either 1<<59 or 4GB mode; dynamic switching is
not supported (could be via sysfs).

This is a rebased version of
https://lore.kernel.org/kvm/20191202015953.127902-1-aik@ozlabs.ru/

This is based on sha1
71c3a888cbca Linus Torvalds "Merge tag 'powerpc-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux".

Please comment. Thanks.



Alexey Kardashevskiy (5):
  powerpc/powernv/ioda: Move TCE bypass base to PE
  powerpc/powernv/ioda: Rework for huge DMA window at 4GB
  powerpc/powernv/ioda: Allow smaller TCE table levels
  powerpc/powernv/phb4: Add 4GB IOMMU bypass mode
  vfio/spapr_tce: Advertise and allow a huge DMA windows at 4GB

 arch/powerpc/include/asm/iommu.h              |   2 +
 arch/powerpc/include/asm/opal-api.h           |   9 +-
 arch/powerpc/include/asm/opal.h               |   2 +
 arch/powerpc/platforms/powernv/pci.h          |   2 +-
 include/uapi/linux/vfio.h                     |   2 +
 arch/powerpc/platforms/powernv/npu-dma.c      |   1 +
 arch/powerpc/platforms/powernv/opal-call.c    |   2 +
 arch/powerpc/platforms/powernv/pci-ioda-tce.c |   4 +-
 arch/powerpc/platforms/powernv/pci-ioda.c     | 229 ++++++++++++++----
 drivers/vfio/vfio_iommu_spapr_tce.c           |  10 +-
 10 files changed, 207 insertions(+), 56 deletions(-)

-- 
2.17.1