Setting up the PCIe support

Edit online

Ubuntu 22.04 LTS LPAR mode z/VM guest KVM guest

Configure the PCIe support through the pci= kernel parameter.

PCIe devices are automatically configured during the system boot process. In contrast to most IBM Z® devices, all PCIe devices that are in a configured state are automatically set online. PCIe devices that are in stand-by state are not automatically enabled.

Scanning of PCIe devices is enabled by default. To disable use of PCI devices, set the kernel command line parameter pci=off.

Figure 1. PCI kernel parameter syntax

1 
2.1! pci=on
2.1? pci=off
1? pci=nomio
1? pci=norid
where:
pci=
off
disables automatic scanning of PCIe devices.
on
enables automatic scanning of PCIe devices (default).
pci=nomio
if available, PCIe uses enhanced instructions as introduced with z15®. Specify this kernel parameter to use the previous instructions.
pci=norid
as of Ubuntu 20.04.1, PCI function addresses follow an Alternative Routing-ID Interpretation (ARI) conform format if it is supported by the system environment. Specify this kernel parameter to use the previous format.
Attention: Other PCI kernel parameters do not apply to IBM Z and might have adverse effects on your system.