AMD-Vi support for IOMMU sysfs. This allows us to associate devices
with a specific IOMMU device and examine the capabilities and features
of that IOMMU. The AMD IOMMU is hosted on and actual PCI device, so
we make that device the parent for the IOMMU class device. This
initial implementaiton ex
IOMMUs currently have no common representation to userspace, most
seem to have no representation at all aside from a few printks
on bootup. There are however features of IOMMUs that are useful
to know about. For instance the IOMMU might support superpages,
making use of processor large/huge pages
Users want to know the features of their hardware and we need a better
way to get it than parsing it out of dmesg. This series creates an
IOMMU class and allows drivers to create and destroy a device within
that class. Drivers may also link and unlink devices to expose the
association of a device
Register our DRHD IOMMUs, cross link devices, and provide a base set
of attributes for the IOMMU. Note that IRQ remapping support parses
the DMAR table very early in boot, well before the iommu_class can
reasonably be setup, so our registration is split between
intel_iommu_init(), which occurs lat
The user of the IOMMU API domain expects to have full control of
the IOVA space for the domain. RMRRs are fundamentally incompatible
with that idea. We can neither map the RMRR into the IOMMU API
domain, nor can we guarantee that the device won't continue DMA with
the area described by the RMRR a
