diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-thunderbolt | 3 | ||||
| -rw-r--r-- | Documentation/admin-guide/thunderbolt.rst | 15 |
2 files changed, 13 insertions, 5 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-thunderbolt b/Documentation/ABI/testing/sysfs-bus-thunderbolt index 4ed2297..151584a 100644 --- a/Documentation/ABI/testing/sysfs-bus-thunderbolt +++ b/Documentation/ABI/testing/sysfs-bus-thunderbolt @@ -35,6 +35,9 @@ Description: This attribute holds current Thunderbolt security level minimum. User needs to authorize each device. dponly: Automatically tunnel Display port (and USB). No PCIe tunnels are created. + usbonly: Automatically tunnel USB controller of the + connected Thunderbolt dock (and Display Port). All + PCIe links downstream of the dock are removed. What: /sys/bus/thunderbolt/devices/.../authorized Date: Sep 2017 diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin-guide/thunderbolt.rst index 9948ec3..35fccba 100644 --- a/Documentation/admin-guide/thunderbolt.rst +++ b/Documentation/admin-guide/thunderbolt.rst @@ -21,11 +21,11 @@ vulnerable to DMA attacks. Security levels and how to use them ----------------------------------- Starting with Intel Falcon Ridge Thunderbolt controller there are 4 -security levels available. The reason for these is the fact that the -connected devices can be DMA masters and thus read contents of the host -memory without CPU and OS knowing about it. There are ways to prevent -this by setting up an IOMMU but it is not always available for various -reasons. +security levels available. Intel Titan Ridge added one more security level +(usbonly). The reason for these is the fact that the connected devices can +be DMA masters and thus read contents of the host memory without CPU and OS +knowing about it. There are ways to prevent this by setting up an IOMMU but +it is not always available for various reasons. The security levels are as follows: @@ -52,6 +52,11 @@ The security levels are as follows: USB. No PCIe tunneling is done. In BIOS settings this is typically called *Display Port Only*. + usbonly + The firmware automatically creates tunnels for the USB controller and + Display Port in a dock. All PCIe links downstream of the dock are + removed. + The current security level can be read from ``/sys/bus/thunderbolt/devices/domainX/security`` where ``domainX`` is the Thunderbolt domain the host controller manages. There is typically |
