Comment 0 for bug 1940906

There are 3 options to present a gpu to a guest:

- PCI passthrough
- SR-IOV
- vGPUs

The later is actually not usable with nova-compute charm, as the [devices] section of nova.conf is not handled (see [1] [2]).

A first step, which should be pretty strait forward, would be to allow a single value for "enabled_vgpu_types".

In terms of documentation, if the GPU driver is correctly installed on the hypervisor (qemu-kvm here), vgpu type can be discovered either with "mdevctl types" command or by listing "/sys/bus/pci/devices/0000:XX:YY.0/mdev_supported_types" path of the pci device.

[1] https://docs.openstack.org/nova/ussuri/admin/virtual-gpu.html
[2] https://docs.openstack.org/nova/ussuri/configuration/config.html#devices.enabled_vgpu_types