[PATCH kernel v2 0/7] powerpc/powenv/ioda: Allow huge DMA window at 4GB

From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: linuxppc-dev@lists.ozlabs.org
Cc: kvm@vger.kernel.org, Fabiano Rosas <farosas@linux.ibm.com>,
	Alexey Kardashevskiy <aik@ozlabs.ru>,
	Alistair Popple <alistair@popple.id.au>,
	kvm-ppc@vger.kernel.org,
	David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH kernel v2 0/7] powerpc/powenv/ioda: Allow huge DMA window at 4GB
Date: Mon, 23 Mar 2020 18:53:47 +1100	[thread overview]
Message-ID: <20200323075354.93825-1-aik@ozlabs.ru> (raw)

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/

The main change since v1 is that now it is 7 patches with
clearer separation of steps.

This is based on 6c90b86a745a "Merge tag 'mmc-v5.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc"

Please comment. Thanks.

Alexey Kardashevskiy (7):
  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: Use IOMMU instead of bypassing
  powerpc/iommu: Add a window number to
    iommu_table_group_ops::get_table_size
  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              |   3 +
 arch/powerpc/include/asm/opal-api.h           |   9 +-
 arch/powerpc/include/asm/opal.h               |   2 +
 arch/powerpc/platforms/powernv/pci.h          |   4 +-
 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     | 234 ++++++++++++++----
 drivers/vfio/vfio_iommu_spapr_tce.c           |  17 +-
 10 files changed, 213 insertions(+), 65 deletions(-)

-- 
2.17.1