Configure PCI passthrough for guests¶

Note

Consider this section as part of Deploy an OpenStack cluster.

The Peripheral Component Interconnect (PCI) passthrough feature in OpenStack allows full access and direct control over physical PCI devices in guests. The mechanism applies to any kind of PCI devices including a Network Interface Card (NIC), Graphics Processing Unit (GPU), and any other device that can be attached to a PCI bus. The only requirement for the guest to properly use the device is to correctly install the driver.

To enable PCI passthrough in a MOSK deployment:

For Linux X86 compute nodes, verify that the following features are enabled on the host:
- VT-d in BIOS
- IOMMU on the host operating system as described in Enable SR-IOV with OVS.
Configure the nova-api service that is scheduled on OpenStack controllers nodes. To generate the alias for PCI in nova.conf, add the alias configuration through the OpenStackDeployment CR.

Note

When configuring PCI with SR-IOV on the same host, the values specified in alias take precedence. Therefore, add the SR-IOV devices to passthrough_whitelist explicitly.

For example:
```
spec:
  services:
    compute:
      nova:
        values:
          conf:
            nova:
              pci:
                alias: '{ "vendor_id":"8086", "product_id":"154d", "device_type":"type-PF", "name":"a1" }'
```

Configure the nova-compute service that is scheduled on OpenStack compute nodes. To enable Nova to pass PCI devices to virtual machines, configure the passthrough_whitelist section in nova.conf through the node-specific overrides in the OpenStackDeployment CR. For example:

spec:
  nodes:
    <NODE-LABEL>::<NODE-LABEL-VALUE>:
      services:
        compute:
          nova:
            nova_compute:
              values:
                conf:
                  nova:
                    pci:
                      alias: '{ "vendor_id":"8086", "product_id":"154d", "device_type":"type-PF", "name":"a1" }'
                      passthrough_whitelist: |
                        [{"devname":"enp216s0f0","physical_network":"sriovnet0"}, { "vendor_id": "8086", "product_id": "154d" }]