Sometimes, a picture says more than a thousand words: https://imgur.com/a/flar7CO

This is Intel SR-IOV graphics virtualization in action.

Modern applications often require graphics acceleration to run at their full potential, which is often a problem in virtual machines. Graphics virtualization helps solve this and provide near-native graphics performance in virtualized environments. Read about the support for SR-IOV graphics virtualization we, at Cyberus Technology, have built into our KVM backend for VirtualBox.

This does appear to be open source under the same terms as the VirtualBox source, but unfortunately it defers to a COPYING file not present in their repo: https://github.com/cyberus-technology/virtualbox-kvm#licensi...

It was here: https://github.com/cyberus-technology/virtualbox-kvm/blob/de... Since 7 of March they've moved to publishing the patch set only instead of the full VirtualBox code with KVM-related patches applied.

Anyone have any idea how/ if bhyve, nvmm or vmm could be supported in the same way . VirtualBox as a front end to various backend could be very useful.

Since version 7.0, VirtualBox supports the NEM (Native Execution Manager) mode for other hypervisors. With the NEM, basically all hypervisors can be supported as backend.