BugLink: http://bugs.launchpad.net/bugs/1607404

commit 522e5cb7 upstream.

There is a race condition in the AMD IOMMU init code that
causes requested unity mappings to be blocked by the IOMMU
for a short period of time. This results on boot failures
and IO_PAGE_FAULTs on some machines.

Fix this by making sure the unity mappings are installed
before all other DMA is blocked.

Fixes: aafd8ba0 ('iommu/amd: Implement add_device and remove_device')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>