vfio: platform: support No-IOMMU mode

The vfio No-IOMMU mode was supported by this
'commit 03a76b60f8ba2797 ("vfio: Include No-IOMMU mode")',
but it only support vfio-pci.

Using vfio_iommu_group_get/put, but not iommu_group_get/put,
the platform devices can be exposed to userspace with
CONFIG_VFIO_NOIOMMU and the "enable_unsafe_noiommu_mode"
option enabled.

From 'commit 03a76b60f8ba2797 ("vfio: Include No-IOMMU mode")',
"This should make it very clear that this mode is not safe.
Additionally, CAP_SYS_RAWIO privileges are necessary to work
with groups and containers using this mode.  Groups making
use of this support are named /dev/vfio/noiommu-$GROUP and
can only make use of the special VFIO_NOIOMMU_IOMMU for the
container.  Use of this mode, specifically binding a device
without a native IOMMU group to a VFIO bus driver will taint
the kernel and should therefore not be considered supported."

Signed-off-by: Peng Fan <[email protected]>
Cc: Eric Auger <[email protected]>
Cc: Baptiste Reynal <[email protected]>
Cc: Alex Williamson <[email protected]>
Reviewed-by: Eric Auger <[email protected]>
Signed-off-by: Alex Williamson <[email protected]>

0 files changed, 0 insertions, 0 deletions