Introduction

The partial_dtb_gen tool is a simple tool for creating partial DT files used for passthrough of devices to Dom0less-DomUs running over Xen. The script takes as input a complete Linux DTB file, a Template DTS/DTB file and a node which to transfer from the former to the latter, updating its properties with respect to the xen passthrough format. Also, the script will add all the referenced memory-regions of the node to the output DTS file. The output of the script is a "passthrough.dts" file, which will contain the aforementioned characteristics.

How to use

The tool takes the following (required) parameters:

• -i (--input_dt) <path_to_linux_dtb> - Path to a complete Linux DTB file, where the requested node's attributes/subnodes will be taken from
• -t (--template_dt) <path_to_template_dt> - Path to a baseline DTS file, which will be the starting point of the final product of the script. The node from the input DT will be merged with the already-existing node in the template DT, without overwriting its properties. Therefore, if we want to set some properties to the node, we should do it in the template DT, before the script is run.
• -n (--passthrough_node) <path_to_node> - Full path to the node we want to have in the script's output DT, along with its subnodes and memory-region references.

Running example

Let's say we want to passthrough the '/ethernet@4033c000' node. We can run the following command:

python3 partial_dtb_gen.py -i <path_to_linux_DTB> -t examples/template.dts -n "/ethernet@4033c000"