The IOMMU driver changes were merged this week for Linux 6.18 with new material to benefit Intel, AMD, Apple, and RISC-V systems.
The Intel VT-d IOMMU driver has been updated against the latest upstream VT-d specification and brings several fixes and code clean-ups.
Over on the AMD side the AMD-Vi driver now is able to cope with Kdump boot handling when SEV-SNP is enabled for secure nested paging.
The Apple DART driver for the Apple Silicon Linux efforts is also now able to handle four-level page tables. The T602x-based SoCs like the Apple M2 Pro / Max / Ultra support a 42-bit IAS and thus io-pgtable and apple-dart code is now adapted to be able to support 4-level page tables.
Lastly the RISC-V IOMMU driver now supports ACPI. With RISC-V ACPI environments there is the RISC-V IO Mapping Table (RIMT) table for communicating IOMMU information to the operating system.
More details on these IOMMU changes for Linux 6.18 via this pull request that is already merged to Linux Git.