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qgraph support for device tree discovery

Summary: Enable tests for the qgraph driver framework to discover devices using a device tree, instead of having to specify the devices on the machine manually.

qgraph, developed during GSoC 2018 (merging in progress), implements an introspectable description of QEMU's supported machine types and a set of drivers that tests can use to start a guest and interact with its devices. Currently, PCI is the only discoverable bus implemented in qgraph; any non-PCI device must be listed manually in the machine type. The purpose of this project is to add support to qgraph for reading a device tree and selecting tests based on the OpenFirmware device names found in the device tree. The device tree can be provided by the virtual machine, or it can be read from an external file.

If the task turns out to be too short to fill the whole internship, the remaining time can be filled by writing new tests for devices that are usually exposed as part of a device tree.


  • KVM Forum 2018 presentation on qtest: video
  • last version of the qgraph framework: patchew


  • Skill level: intermediate
  • Language: C
  • Mentor: Paolo Bonzini <>, Laurent Vivier <>
  • Suggested by: Paolo Bonzini <> (IRC nick bonzini)