This enables PAPR defined feature called Dynamic DMA windows (DDW).
Each Partitionable Endpoint (IOMMU group) has a separate DMA window on
a PCI bus where devices are allows to perform DMA. By default there is
1 or 2GB window allocated at the host boot time and these windows are
used when an IOMMU group is passed to the userspace (guest). These windows
are mapped at zero offset on a PCI bus.
Hi-speed devices may suffer from limited size of this window. On the host
side a TCE bypass mode is enabled on POWER8 CPU which implements
direct mapping of the host memory to a PCI bus at 1<<59.
For the guest, PAPR defines a DDW RTAS API which allows the pseries guest
to query the hypervisor if it supports DDW and what are the parameters
of possible windows.
Currently POWER8 supports 2 DMA windows per PE - already mentioned and used
small 32bit window and 64bit window which can only start from 1<<59 and
can support various page sizes.
This patchset reworks PPC IOMMU code and adds necessary structures
to extend it to support big windows.
When the guest detectes the feature and the PE is capable of 64bit DMA,
it does:
1. query to hypervisor about number of available windows and page masks;
2. creates a window with the biggest possible page size (current guests can do
64K or 16MB TCEs);
3. maps the entire guest RAM via H_PUT_TCE* hypercalls
4. switches dma_ops to direct_dma_ops on the selected PE.
Once this is done, H_PUT_TCE is not called anymore and the guest gets
maximum performance.
Changes:
v3:
* (!) redesigned the whole thing
* multiple IOMMU groups per PHB -> one PHB is needed for VFIO in the guest ->
no problems with locked_vm counting; also we save memory on actual tables
* guest RAM preregistration is required for DDW
* PEs (IOMMU groups) are passed to VFIO with no DMA windows at all so
we do not bother with iommu_table::it_map anymore
* added multilevel TCE tables support to support really huge guests
v2:
* added missing __pa() in "powerpc/powernv: Release replaced TCE"
* reposted to make some noise
Alexey Kardashevskiy (24):
vfio: powerpc/spapr: Move page pinning from arch code to VFIO IOMMU
driver
vfio: powerpc/iommu: Check that TCE page size is equal to it_page_size
powerpc/powernv: Do not set "read" flag if direction==DMA_NONE
vfio: powerpc/spapr: Use it_page_size
vfio: powerpc/spapr: Move locked_vm accounting to helpers
powerpc/iommu: Move tce_xxx callbacks from ppc_md to iommu_table
powerpc/iommu: Introduce iommu_table_alloc() helper
powerpc/spapr: vfio: Switch from iommu_table to new powerpc_iommu
powerpc/iommu: Fix IOMMU ownership control functions
powerpc/powernv/ioda2: Rework IOMMU ownership control
powerpc/powernv/ioda/ioda2: Rework tce_build()/tce_free()
powerpc/iommu/powernv: Release replaced TCE
powerpc/pseries/lpar: Enable VFIO
vfio: powerpc/spapr: Register memory
poweppc/powernv/ioda2: Rework iommu_table creation
powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_create_table
powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_set_window
powerpc/iommu: Split iommu_free_table into 2 helpers
powerpc/powernv: Implement multilevel TCE tables
powerpc/powernv: Change prototypes to receive iommu
powerpc/powernv/ioda: Define and implement DMA table/window management
callbacks
powerpc/iommu: Get rid of ownership helpers
vfio/spapr: Enable multiple groups in a container
vfio: powerpc/spapr: Support Dynamic DMA windows
arch/powerpc/include/asm/iommu.h | 107 +++-
arch/powerpc/include/asm/machdep.h | 25 -
arch/powerpc/kernel/eeh.c | 2 +-
arch/powerpc/kernel/iommu.c | 282 +++------
arch/powerpc/kernel/vio.c | 5 +
arch/powerpc/platforms/cell/iommu.c | 8 +-
arch/powerpc/platforms/pasemi/iommu.c | 7 +-
arch/powerpc/platforms/powernv/pci-ioda.c | 470 ++++++++++++---
arch/powerpc/platforms/powernv/pci-p5ioc2.c | 21 +-
arch/powerpc/platforms/powernv/pci.c | 130 +++--
arch/powerpc/platforms/powernv/pci.h | 14 +-
arch/powerpc/platforms/pseries/iommu.c | 99 +++-
arch/powerpc/sysdev/dart_iommu.c | 12 +-
drivers/vfio/vfio_iommu_spapr_tce.c | 874 ++++++++++++++++++++++++----
include/uapi/linux/vfio.h | 53 +-
15 files changed, 1584 insertions(+), 525 deletions(-)
--
2.0.0
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
