On Thu, 8 Sep 2022 21:34:38 +0300 Yishai Hadas <yishaih@xxxxxxxxxx> wrote: > This series adds device DMA logging uAPIs and their implementation as > part of mlx5 driver. > > DMA logging allows a device to internally record what DMAs the device is > initiating and report them back to userspace. It is part of the VFIO > migration infrastructure that allows implementing dirty page tracking > during the pre copy phase of live migration. Only DMA WRITEs are logged, > and this API is not connected to VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE. > > The uAPIs are based on the FEATURE ioctl as were introduced earlier by > the below RFC [1] and follows the notes that were discussed in the > mailing list. > > It includes: > - A PROBE option to detect if the device supports DMA logging. > - A SET option to start device DMA logging in given IOVAs ranges. > - A GET option to read back and clear the device DMA log. > - A SET option to stop device DMA logging that was previously started. > > Extra details exist as part of relevant patches in the series. > > In addition, the series adds some infrastructure support for managing an > IOVA bitmap done by Joao Martins. > > It abstracts how an IOVA range is represented in a bitmap that is > granulated by a given page_size. So it translates all the lifting of > dealing with user pointers into its corresponding kernel addresses. > This new functionality abstracts the complexity of user/kernel bitmap > pointer usage and finally enables an API to set some bits. > > This functionality will be used as part of IOMMUFD series for the system > IOMMU tracking. > > Finally, we come with mlx5 implementation based on its device > specification for the DMA logging APIs. > > The matching qemu changes can be previewed here [2]. > They come on top of the v2 migration protocol patches that were sent > already to the mailing list. > > Note: > - As this series touched mlx5_core parts we may need to send the > net/mlx5 patches as a pull request format to VFIO to avoid conflicts > before acceptance. > > [1] https://lore.kernel.org/all/20220501123301.127279-1-yishaih@xxxxxxxxxx/T/ > [2] https://github.com/avihai1122/qemu/commits/device_dirty_tracking > > Changes from V6: https://lore.kernel.org/all/20220905105852.26398-11-yishaih@xxxxxxxxxx/T/ > - Use the first two patches from the PR that was sent by Leon, no code > change was involved. > - Patch #5: > * Add a documentation note near vfio_log_ops as Alex suggested. Pulled topic branch from Leon and applied 3-10 to the vfio next branch for v6.1. Thanks, Alex
