IOTLB

IOMMU IOTLB Invalidation Controls When DMA Remapping Takes Effect

IOMMU IOTLB Invalidation Controls When DMA Remapping Takes Effect Changing an IOMMU page-table entry does not necessarily change the translation used by the next DMA request. An IOMMU can cache address translations in an I/O translation lookaside buffer, commonly called an IOTLB. Software must invalidate affected cached state when a mapping is removed or replaced, then observe the invalidation semantics required by that IOMMU before treating the old translation as retired.