Changes since v2: - Some patches got removed from the series and sent by themselves, - New tbl created for DDW + indirect mapping reserves MMIO32 space, - Improved reserved area algorithm, - Improved commit messages, - Removed define for default DMA window prop name, - Avoided some unnecessary renaming, - Removed some unnecessary empty lines, - Changed some code moving to forward declarations. v2 Link: http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=201210&state=%2A&archive=both
On Thu, 2021-04-22 at 04:07 -0300, Leonardo Bras wrote: > So far it's assumed possible to map the guest RAM 1:1 to the bus, which > works with a small number of devices. SRIOV changes it as the user can > configure hundreds VFs and since phyp preallocates TCEs and does not > allow IOMMU pages bigger than 64K, it has to limit the number of TCEs > per a PE to limit waste of physical pages. > > As of today, if the assumed direct mapping is not possible, DDW creation > is skipped and the default DMA window "ibm,dma-window" is used instead. > > Using the DDW instead of the default DMA window may allow to expand the > amount of memory that can be DMA-mapped, given the number of pages (TCEs) > may stay the same (or increase) and the default DMA window offers only > 4k-pages while DDW may offer larger pages (4k, 64k, 16M ...). > > Patch #1 replaces hard-coded 4K page size with a variable containing the > correct page size for the window. > > Patch #2 introduces iommu_table_in_use(), and replace manual bit-field > checking where it's used. It will be used for aborting enable_ddw() if > there is any current iommu allocation and we are trying single window > indirect mapping. > > Patch #3 introduces iommu_pseries_alloc_table() that will be helpful > when indirect mapping needs to replace the iommu_table. > > Patch #4 adds helpers for adding DDWs in the list. > > Patch #5 refactors enable_ddw() so it returns if direct mapping is > possible, instead of DMA offset. It helps for next patches on > indirect DMA mapping and also allows DMA windows starting at 0x00. > > Patch #6 bring new helper to simplify enable_ddw(), allowing > some reorganization for introducing indirect mapping DDW. > > Patch #7 adds new helper _iommu_table_setparms() and use it in other > *setparams*() to fill iommu_table. It will also be used for creating a > new iommu_table for indirect mapping. > > Patch #8 updates remove_dma_window() to accept different property names, > so we can introduce a new property for indirect mapping. > > Patch #9 extracts find_existing_ddw_windows() into > find_existing_ddw_windows_named(), and calls it by it's property name. > This will be useful when the property for indirect mapping is created, > so we can search the device-tree for both properties. > > Patch #10: > Instead of destroying the created DDW if it doesn't map the whole > partition, make use of it instead of the default DMA window as it improves > performance. Also, update the iommu_table and re-generate the pools. > It introduces a new property name for DDW with indirect DMA mapping. > > Patch #11: > Does some renaming of 'direct window' to 'dma window', given the DDW > created can now be also used in indirect mapping if direct mapping is not > available. > > All patches were tested into an LPAR with an virtio-net interface that > allows default DMA window and DDW to coexist. > > Leonardo Bras (11): > powerpc/pseries/iommu: Replace hard-coded page shift > powerpc/kernel/iommu: Add new iommu_table_in_use() helper > powerpc/pseries/iommu: Add iommu_pseries_alloc_table() helper > powerpc/pseries/iommu: Add ddw_list_new_entry() helper > powerpc/pseries/iommu: Allow DDW windows starting at 0x00 > powerpc/pseries/iommu: Add ddw_property_create() and refactor > enable_ddw() > powerpc/pseries/iommu: Reorganize iommu_table_setparms*() with new > helper > powerpc/pseries/iommu: Update remove_dma_window() to accept property > name > powerpc/pseries/iommu: Find existing DDW with given property name > powerpc/pseries/iommu: Make use of DDW for indirect mapping > powerpc/pseries/iommu: Rename "direct window" to "dma window" > > arch/powerpc/include/asm/iommu.h | 1 + > arch/powerpc/include/asm/tce.h | 8 - > arch/powerpc/kernel/iommu.c | 65 ++-- > arch/powerpc/platforms/pseries/iommu.c | 504 +++++++++++++++---------- > 4 files changed, 338 insertions(+), 240 deletions(-) >
