Options for x86 IOMMUs (VT-ds)

The configurations described here are for use with the smmu-vtd.so and smmu-vtd-safety.so support libraries for IOMMUs with the x86 VT-d architecture. These support libraries implement the code to communicate with x86 VT-ds, as specified in Intel Virtualization Technology for Directed I/O Architecture Specification. Intel, Nov. 2017 (D51397-009, Rev. 2.5).

To load these support libraries, you must set the smmu option's smmu_type argument to the name of the support library:

• smmu-vtd.so for non-safety systems
• smmu-vtd-safety.so for safety-related systems

Options

The following describes the options for a smmuman service using a smmu-vtd.so or smmu-vtd-safety.so support library for IOMMUs that use the x86 VT-d architecture.

smmu_type_parm

On boards with Intel VT-d IOMMU hardware, the syntax for smmu_type_parm is as follows:

require | ignore

require

The VT-d information must be present in the ACPI tables.

ignore

Ignore ACPI information.

CAUTION:

Use ignore only if the board firmware is incorrect for your board design and you need to manually input the VT-d unit and device information that would normally be found in these tables. Consult your board manufacturer's documentation. For example, see “Intel Virtualization Technology for Directed I/O” available from software.intel.com/en-us/articles/intel-sdm.

If neither required nor ignore is specified, the smmuman service doesn't require the ACPI tables, but uses them if they are present.

smmu_unit_parm

On boards with Intel VT-d IOMMU hardware, the syntax for smmu_type_parm is as follows:

vtd_paddr

vtd_paddr

The base physical address of the VT-d device registers for the unit.

smmu_use_parm

On boards with Intel VT-d IOMMU hardware, no value is required or permitted for smmu_use_parm.

smmuman smmu vtd