# Revision history [back]

### PCI-PT ports association & pci_alias

Hi, I am currently playing with PCI Passthrough VMs.

The compute node has 4 identical PCI-PT ports (2 NICs with 2 10Gb ports, Intel). I configured the pci_alias = {"vendor_id": "8086", "product_id": "10fb", "name":"intel_pt"} and configured a corresponding flavor with nova flavor-key VNF.4PCIPT set "pci_passthrough:alias"="intel_pt:4"

I always create the VM with an heat template, verifying that all vNICS are always mapped to PCI-PT ports in the same order (lower addr bus - higher port number is the first one, followed by lower addr bus - higher port number -1)

e.g.:

0000:03:00.1

0000:03:00.0

0000:04:00.1

0000:04:00.0

Is there anyone that could confirm this behaviour, in order to be sure it is deterministic. Where could I search for the logic behind this behaviour?

Another approach to specifically map PCI-PT devices to vNICs could be to define a specific pci_alias that maps specifically to a predefined port. Could it be possible to define a pci_alias referring to 0000:04:00.1 port only (assuming all NIC ports are identical, both from vendor and product IDs perspective)

### PCI-PT ports association & pci_alias

Hi, I am currently playing with PCI Passthrough VMs.

The compute node has 4 identical PCI-PT ports (2 NICs with 2 10Gb ports, Intel). I configured the pci_alias = {"vendor_id": "8086", "product_id": "10fb", "name":"intel_pt"} and configured a corresponding flavor with nova flavor-key VNF.4PCIPT set "pci_passthrough:alias"="intel_pt:4"

I always create the VM with an heat template, verifying that all vNICS are always mapped to PCI-PT ports in the same order (lower addr bus - higher port number is the first one, followed by lower addr bus - higher port number -1)

e.g.:

0000:03:00.1

0000:03:00.0

0000:04:00.1

0000:04:00.0

Is there anyone that could confirm this behaviour, in order to be sure it is deterministic. Where could I search for the logic behind this behaviour?

Another approach to specifically map PCI-PT devices to vNICs could be to define a specific pci_alias that maps specifically to a predefined port. Could it be possible to define a pci_alias referring to 0000:04:00.1 port only (assuming all NIC ports are identical, both from vendor and product IDs perspective)