> From: Paul Durrant [mailto:[email protected]] > Sent: Thursday, December 6, 2018 11:34 PM > > This patch removes any implicit flushing that occurs in the implementation > of map and unmap operations and adds new iommu_map/unmap() > wrapper > functions. To maintain sematics of the iommu_legacy_map/unmap() > wrapper > functions, these are modified to call the new wrapper functions and then > perform an explicit flush operation. > > Because VT-d currently performs two different types of flush dependent > upon > whether a PTE is being modified versus merely added (i.e. replacing a non- > present PTE) 'iommu flush flags' are defined by this patch and the > iommu_ops map_page() and unmap_page() methods are modified to OR > the type > of flush necessary for the PTE that has been populated or depopulated into > an accumulated flags value. The accumulated value can then be passed into > the explicit flush operation. > > The ARM SMMU implementations of map_page() and unmap_page() > currently > perform no implicit flushing and therefore the modified methods do not > adjust the flush flags. > > NOTE: The per-cpu 'iommu_dont_flush_iotlb' is respected by the > iommu_legacy_map/unmap() wrapper functions and therefore this now > applies to all IOMMU implementations rather than just VT-d. > > Signed-off-by: Paul Durrant <[email protected]>
Reviewed-by: Kevin Tian <[email protected]> _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
