On 10/19/23 4:27 AM, Joao Martins wrote:
Add to iommu domain operations a set of callbacks to perform dirty tracking, particulary to start and stop tracking and to read and clear the dirty data. Drivers are generally expected to dynamically change its translation structures to toggle the tracking and flush some form of control state structure that stands in the IOVA translation path. Though it's not mandatory, as drivers can also enable dirty tracking at boot, and just clear the dirty bits before setting dirty tracking. For each of the newly added IOMMU core APIs: iommu_cap::IOMMU_CAP_DIRTY: new device iommu_capable value when probing for capabilities of the device. .set_dirty_tracking(): an iommu driver is expected to change its translation structures and enable dirty tracking for the devices in the iommu_domain. For drivers making dirty tracking always-enabled, it should just return 0. .read_and_clear_dirty(): an iommu driver is expected to walk the pagetables for the iova range passed in and use iommu_dirty_bitmap_record() to record dirty info per IOVA. When detecting that a given IOVA is dirty it should also clear its dirty state from the PTE, *unless* the flag IOMMU_DIRTY_NO_CLEAR is passed in -- flushing is steered from the caller of the domain_op via iotlb_gather. The iommu core APIs use the same data structure in use for dirty tracking for VFIO device dirty (struct iova_bitmap) abstracted by iommu_dirty_bitmap_record() helper function. domain::dirty_ops: IOMMU domains will store the dirty ops depending on whether the iommu device supports dirty tracking or not. iommu drivers can then use this field to figure if the dirty tracking is supported+enforced on attach. The enforcement is enable via domain_alloc_user() which is done via IOMMUFD hwpt flag introduced later. Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx> --- include/linux/io-pgtable.h | 4 +++ include/linux/iommu.h | 56 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 60 insertions(+)
Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> Best regards, baolu
