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Diffstat (limited to 'Documentation/admin-guide/thunderbolt.rst')
| -rw-r--r-- | Documentation/admin-guide/thunderbolt.rst | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin-guide/thunderbolt.rst index 9948ec36a204..35fccba6a9a6 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 |