iommu options only relevant to the AMD GART hardware IOMMU:
<size> Set the size of the remapping area in bytes.
allowed Overwrite iommu off workarounds for specific chipsets.
- fullflush Flush IOMMU on each allocation (default).
- nofullflush Don't use IOMMU fullflush.
leak Turn on simple iommu leak tracing (only when
CONFIG_IOMMU_LEAK is on). Default number of leak pages
is 20.