[RFC PATCH v4 00/13] iommu/smmuv3: Implement hardware dirty log tracking

[Keqian Zhu]

Hi Robin, Will and everyone,

I think this series is relative mature now, please give your valuable suggestions,
thanks!


This patch series is split from the series[1] that containes both IOMMU part and
VFIO part. The VFIO part will be sent out in another series.

[1] https://lore.kernel.org/linux-iommu/20210310090614.26668-1-zhukeqian1@xxxxxxxxxx/

changelog:

v4:
 - Modify the framework as suggested by Baolu, thanks!
 - Add trace for iommu ops.
 - Extract io-pgtable part.

v3:
 - Merge start_dirty_log and stop_dirty_log into switch_dirty_log. (Yi Sun)
 - Maintain the dirty log status in iommu_domain.
 - Update commit message to make patch easier to review.

v2:
 - Address all comments of RFC version, thanks for all of you ;-)
 - Add a bugfix that start dirty log for newly added dma ranges and domain.



Hi everyone,

This patch series introduces a framework of iommu dirty log tracking, and smmuv3
realizes this framework. This new feature can be used by VFIO dma dirty tracking.

Intention：

Some types of IOMMU are capable of tracking DMA dirty log, such as
ARM SMMU with HTTU or Intel IOMMU with SLADE. This introduces the
dirty log tracking framework in the IOMMU base layer.

Three new essential interfaces are added, and we maintaince the status
of dirty log tracking in iommu_domain.
1. iommu_switch_dirty_log: Perform actions to start|stop dirty log tracking
2. iommu_sync_dirty_log: Sync dirty log from IOMMU into a dirty bitmap
3. iommu_clear_dirty_log: Clear dirty log of IOMMU by a mask bitmap

About SMMU HTTU:

HTTU (Hardware Translation Table Update) is a feature of ARM SMMUv3, it can update
access flag or/and dirty state of the TTD (Translation Table Descriptor) by hardware.
With HTTU, stage1 TTD is classified into 3 types:
                        DBM bit             AP[2](readonly bit)
1. writable_clean         1                       1
2. writable_dirty         1                       0
3. readonly               0                       1

If HTTU_HD (manage dirty state) is enabled, smmu can change TTD from writable_clean to
writable_dirty. Then software can scan TTD to sync dirty state into dirty bitmap. With
this feature, we can track the dirty log of DMA continuously and precisely.

About this series:

Patch 1-3：Introduce dirty log tracking framework in the IOMMU base layer, and two common
           interfaces that can be used by many types of iommu.

Patch 4-6: Add feature detection for smmu HTTU and enable HTTU for smmu stage1 mapping.
           And add feature detection for smmu BBML. We need to split block mapping when
           start dirty log tracking and merge page mapping when stop dirty log tracking,
		   which requires break-before-make procedure. But it might cause problems when the
		   TTD is alive. The I/O streams might not tolerate translation faults. So BBML
		   should be used.

Patch 7-12: We implement these interfaces for arm smmuv3.

Thanks,
Keqian

Jean-Philippe Brucker (1):
  iommu/arm-smmu-v3: Add support for Hardware Translation Table Update

Keqian Zhu (1):
  iommu: Introduce dirty log tracking framework

Kunkun Jiang (11):
  iommu/io-pgtable-arm: Add quirk ARM_HD and ARM_BBMLx
  iommu/io-pgtable-arm: Add and realize split_block ops
  iommu/io-pgtable-arm: Add and realize merge_page ops
  iommu/io-pgtable-arm: Add and realize sync_dirty_log ops
  iommu/io-pgtable-arm: Add and realize clear_dirty_log ops
  iommu/arm-smmu-v3: Enable HTTU for stage1 with io-pgtable mapping
  iommu/arm-smmu-v3: Add feature detection for BBML
  iommu/arm-smmu-v3: Realize switch_dirty_log iommu ops
  iommu/arm-smmu-v3: Realize sync_dirty_log iommu ops
  iommu/arm-smmu-v3: Realize clear_dirty_log iommu ops
  iommu/arm-smmu-v3: Realize support_dirty_log iommu ops

 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   |   2 +
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 268 +++++++++++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  14 +
 drivers/iommu/io-pgtable-arm.c                | 389 +++++++++++++++++-
 drivers/iommu/iommu.c                         | 206 +++++++++-
 include/linux/io-pgtable.h                    |  23 ++
 include/linux/iommu.h                         |  65 +++
 include/trace/events/iommu.h                  |  63 +++
 8 files changed, 1026 insertions(+), 4 deletions(-)

-- 
2.19.1