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Generic IOMMU page table framework

Laurent Pinchart linux-arm-kernel linux-iommu 1 version New

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#Subject and filesSizeRepliesApplied
1/4iommu: introduce generic page table allocation framework+0 -01 reply
1/4iommu: introduce generic page table allocation framework+0 -01 reply
2/4iommu: add ARM LPAE page table allocator+0 -01 reply
2/4iommu: add ARM LPAE page table allocator+0 -01 reply
2/4iommu: add ARM LPAE page table allocator+0 -01 reply

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Cover letter [PATCH 0/4] Generic IOMMU page table framework

Hi Will,

Thank you for the patches.

Quoted 22 lines · On Thursday 27 November 2014 11:51:14 Will Deacon wrote:

Hi all,

This series introduces a generic IOMMU page table allocation framework, implements support for ARM long-descriptors and then ports the arm-smmu driver over to the new code.

There are a few reasons for doing this:

- Page table code is hard, and I don't enjoy shopping

- A number of IOMMUs actually use the same table format, but currently duplicate the code

- It provides a CPU (and architecture) independent allocator, which may be useful for some systems where the CPU is using a different table format for its own mappings

As illustrated in the final patch, an IOMMU driver interacts with the allocator by passing in a configuration structure describing the input and output address ranges, the supported pages sizes and a set of ops for performing various TLB invalidation and PTE flushing routines.

Quoted 4 lines

The LPAE code implements support for 4k/2M/1G, 16k/32M and 64k/512M mappings, but I decided not to implement the contiguous bit in the interest of trying to keep the code semi-readable. This could always be added later, if needed.

Do you have any idea how much the contiguous bit can improve performances in real use cases ?

Quoted 32 lines

I also included some self-tests for the LPAE implementation. Ideally we'd merge these, but I'm also happy to drop them if there are objections.

Tested with the self-tests, but also VFIO + MMU-500 at stage-1 and stage-2. Patches taken against my iommu/devel branch (queued by Joerg for 3.19).

All feedback welcome.

Will

--->8

Will Deacon (4):
iommu: introduce generic page table allocation framework
iommu: add ARM LPAE page table allocator
iommu: add self-consistency tests to ARM LPAE IO page table allocator iommu/arm-smmu: make use of generic LPAE allocator

 MAINTAINERS                    |   1 +
 arch/arm64/Kconfig             |   1 -
 drivers/iommu/Kconfig          |  32 +-
 drivers/iommu/Makefile         |   2 +
 drivers/iommu/arm-smmu.c       | 872 +++++++++++---------------------------
 drivers/iommu/io-pgtable-arm.c | 925 ++++++++++++++++++++++++++++++++++++++
 drivers/iommu/io-pgtable.c     |  78 ++++
 drivers/iommu/io-pgtable.h     |  77 ++++
 8 files changed, 1361 insertions(+), 627 deletions(-)
 create mode 100644 drivers/iommu/io-pgtable-arm.c
 create mode 100644 drivers/iommu/io-pgtable.c
 create mode 100644 drivers/iommu/io-pgtable.h
Signature · 3 lines
Regards,

Laurent Pinchart

Read the cover letter in its thread