Credits and notices

Licence

Kayfabe is dual-licensed: you may use, copy, modify and distribute it under either the Apache License 2.0 or the GNU General Public License version 2 or (at your option) any later version (Apache-2.0 OR GPL-2.0-or-later). The texts are LICENSE-APACHE and LICENSE-GPL; LICENSE lists the exceptions.

Exceptions you should know before building or redistributing:

• Some files are derived from gVisor's nvproxy (Copyright The gVisor Authors, Apache License 2.0). They are available under the Apache License 2.0 only until they are re-derived independently. LICENSE lists them.
• The kf3-gpu device is built inside a QEMU source tree, and QEMU as a whole is GPL-2.0. The device links the crates that contain the gVisor-derived files. A QEMU binary built from this tree is therefore not yet distributable under the GPL. Read LICENSE, exception 2, before redistributing one.
• third_party/ holds git submodules (the Linux kernel, NVIDIA's open-gpu-kernel-modules and gVisor), each under its own licence. They are reference sources: not built, linked or copied into kayfabe.
• The broker/ directory (the display broker) is marked GPL-2.0 OR Apache-2.0, where the GPL option is version 2 only; either option may be chosen.
• A file that carries its own copyright or licence notice is under that notice. Traces, logs and captures contain data produced by third-party software and hardware.

Third-party notices

THIRD_PARTY_NOTICES.md holds the full notices. In short:

Crates used only by tests and developer tools are listed in Cargo.lock and are not linked into a shipped artifact.

NVIDIA's open-gpu-kernel-modules source is the reference the generated tables are checked against, and the version a given table comes from is recorded with it.

Related projects

Other projects attempt something close to kayfabe: a virtual NVIDIA GPU for a virtual machine, so that the VM runs the stock NVIDIA driver. They are credited here for readers who want to compare approaches. Kayfabe does not copy code from them.

• Caraxes (silasmue/Caraxes, core MIT, guest module GPL-2.0-only; a fork of UniStuttgart-IKR/Leandro). It serves a synthetic NVIDIA GPU over vfio-user with a stock guest driver. Its quickstart requires a patched Cloud Hypervisor and keeps the host NVIDIA driver bound. The quickstart's example run sets CARAXES_DMA=register, which needs a copy of the binary with the cap_sys_admin capability set with sudo; the quickstart also uses sudo for the network device and the guest driver's module options. Its host-access section separately describes the device as submitting work through the host driver as an unprivileged client. That description does not make the documented run sudo-free.
• Open-IOV (open-iov.org). A community project that runs stock NVIDIA drivers in VMs without a vGPU licence. Its overview describes the host module, vgsp.ko, binding the GPU and exposing virtual GPUs through the mediated-device framework, with the distribution's NVIDIA module unbound in that mode. Its pages do not say whether the host can keep using the card. The install guide requires root or sudo for loading the module and creating virtual GPUs. The overview and install guide describe different host-driver arrangements: the overview says the distribution module stays unbound, while the install guide also describes an emulated path using the distribution driver. Read both before choosing a setup.

Trademarks

NVIDIA, GeForce, CUDA and the like are trademarks of their owners. Windows is a trademark of Microsoft Corporation. All other names are the property of their owners. They are used here only to say what kayfabe works with. Kayfabe is not affiliated with or endorsed by NVIDIA or Microsoft.

No vendor binaries

Kayfabe ships no vendor binaries: no NVIDIA or Microsoft driver, firmware, image or installer. Where the tests and guides use them, you obtain them from the vendor yourself.

The Windows harness downloads, each pinned by SHA-256: Microsoft's Windows 11 Enterprise LTSC 2024 evaluation image, the virtio-win 0.1.302 drivers (Red Hat / Fedora project), Win32-OpenSSH 10.0.0.0p2 (Microsoft) and NVIDIA's 580.88 Windows driver. The test tooling fetches other vendors' benchmark and application installers. A draft note in the repository records that the terms of some of these are unclear (for example the Windows evaluation image, the free edition of Unigine Heaven and FurMark) and that some (3DMark, Geekbench scripting) may not be fetched automatically. Read each vendor's terms before you fetch.

Your licences

You must comply with the licences of the drivers and operating systems you run with kayfabe. In particular:

• The NVIDIA driver licence applies to the driver you install on the host and in the guest, including its limits on datacentre deployment and on hosting.
• Windows must be licensed for the way you use it.

Kayfabe's own licence does not grant any rights to third-party software.

Acknowledgements

• NVIDIA, for publishing the open GPU kernel modules and documentation from which the interfaces are generated (MIT-licensed; notices in THIRD_PARTY_NOTICES.md).
• The gVisor authors, for nvproxy, from which capability allowlists derive, and for the ioctl formats it documents.
• The nouveau and nova developers and the Linux kernel, read as reference.
• The QEMU project.
• The virtio-win project and Red Hat, for the Windows virtio drivers the harness installs.
• The author's earlier projects nvkvm-pv and the archived nvkvm prototype (credits in archive/nvkvm/CREDITS in the repository), from which the display broker was imported.

Questions about a licence or notice

Open an issue in the repository. Report a suspected vulnerability privately: see Security model.

Verified on: not applicable to behaviour; the texts are taken from LICENSE, THIRD_PARTY_NOTICES.md and docs/NOTICES.md as of master (2026-10-26). This page is not legal advice, and the repository marks its own provenance policy wording as a draft awaiting legal review.

View and edit source on GitHub (source: docs/howto/credits.md, master branch)