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

[Keqian Zhu]

Hi all,

The VFIO part is at here: https://lore.kernel.org/kvm/20210507103608.39440-1-zhukeqian1@xxxxxxxxxx/

Thanks,
Keqian

On 2021/5/7 18:21, Keqian Zhu wrote:
> 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(-)
>