Attaching physical PCI devices to guests¶

Configure nova-scheduler (Controller)¶

1. Configure nova-scheduler as specified in Configure nova-scheduler.
2. Restart the nova-scheduler service.

Configure nova-api (Controller)¶

1. Specify the PCI alias for the device.

   Configure a PCI alias a1 to request a PCI device with a vendor_id of 0x8086 and a product_id of 0x154d. The vendor_id and product_id correspond the PCI device with address 0000:41:00.0.

   Edit /etc/nova/nova.conf:

   [pci]
   alias = { "vendor_id":"8086", "product_id":"154d", "device_type":"type-PF", "name":"a1" }
   

   For more information about the syntax of alias, refer to Configuration Options.

2. Restart the nova-api service.

Configure a flavor (Controller)¶

Configure a flavor to request two PCI devices, each with vendor_id of 0x8086 and product_id of 0x154d:

# openstack flavor set m1.large --property "pci_passthrough:alias"="a1:2"

For more information about the syntax for pci_passthrough:alias, refer to Flavors.

Enable PCI passthrough (Compute)¶

Enable VT-d and IOMMU. For more information, refer to steps one and two in Create Virtual Functions.

For Hyper-V compute nodes, the requirements are as follows:

• Windows 10 or Windows / Hyper-V Server 2016 or newer.
• VT-d and SR-IOV enabled on the host.
• Assignable PCI devices.

In order to check the requirements above and if there are any assignable PCI devices, run the following Powershell commands:

Start-BitsTransfer https://raw.githubusercontent.com/Microsoft/Virtualization-Documentation/master/hyperv-samples/benarm-powershell/DDA/survey-dda.ps1
 .\survey-dda.ps1

If the compute node passes all the requirements, the desired assignable PCI devices to be disabled and unmounted from the host, in order to be assignable by Hyper-V. The following can be read for more details: Hyper-V PCI passthrough.

Configure PCI devices (Compute)¶

1. Configure nova-compute to allow the PCI device to pass through to VMs. Edit /etc/nova/nova.conf:

   [pci]
   passthrough_whitelist = { "address": "0000:41:00.0" }
   

   Alternatively specify multiple PCI devices using whitelisting:

   [pci]
   passthrough_whitelist = { "vendor_id": "8086", "product_id": "10fb" }
   

   All PCI devices matching the vendor_id and product_id are added to the pool of PCI devices available for passthrough to VMs.

   For more information about the syntax of passthrough_whitelist, refer to Configuration Options.

2. Specify the PCI alias for the device.

   From the Newton release, to resize guest with PCI device, configure the PCI alias on the compute node as well.

   Configure a PCI alias a1 to request a PCI device with a vendor_id of 0x8086 and a product_id of 0x154d. The vendor_id and product_id correspond the PCI device with address 0000:41:00.0.

   Edit /etc/nova/nova.conf:

   [pci]
   alias = { "vendor_id":"8086", "product_id":"154d", "device_type":"type-PF", "name":"a1" }
   

   For more information about the syntax of alias, refer to Configuration Options.

3. Restart the nova-compute service.

Create instances with PCI passthrough devices¶

The nova-scheduler selects a destination host that has PCI devices available with the specified vendor_id and product_id that matches the alias from the flavor.

# openstack server create --flavor m1.large --image cirros-0.3.5-x86_64-uec --wait test-pci