[hedora]

This sounds like a driver bug / misconfiguration. Once the IOMMU is set up, there isn’t any host side management to be done (other than managing the IOMMU TLB, but unless it’s thrashing, that’s a no-op on the fast path).

At most, each kernel driver has to do an extra addition to map its physical I/O offset to the one exposed to the bus by the IOMMU. With huge pages, there’s approximately one offset per driver, so it lives in cache, probably next to other driver state.