Comment 16 for bug 1824831

I think possible steps for GPU passthrough are as following:
1. Find out valid gpu devices via system host-device-list --a, enable it if not already enabled.
2. Find out all the existing pci alias minus the invalid alias without vendor id and product id via system helm-override-show stx-openstack nova openstack
3. Compose a helm override yaml file containing pci alias found in step2 plus the valid one for gpu with the device id and product id found in step1.
such as below:
conf:
 nova:
  pci:
    alias:
        type: multistring
        values:
        - '{"vendor_id": "8086", "product_id": "0435", "name": "qat-dh895xcc-pf"}'
        - '{"vendor_id": "8086", "product_id": "0443", "name": "qat-dh895xcc-vf"}'
        - '{"vendor_id": "8086", "product_id": "37c8", "name": "qat-c62x-pf"}'
        - '{"vendor_id": "8086", "product_id": "37c9", "name": "qat-c62x-vf"}'
        - '{"vendor_id": "102b", "product_id": "0522","device_type":"type-PF","name": "gpu"}'
4. Override nova helm charts with above yaml file and reapply stx-openstack
5. create flavor with pci_passthrough:alias=gpu:1
6. launch vm using above flavor