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In x86/ACPI world, linux distros are using predictable network interface naming since systemd v197. Which on QEMU based VMs results into path based naming scheme, that names network interfaces based on PCI topology. With itm on has to plug NIC in exactly the same bus/slot, which was used when disk image was first provisioned/configured or one risks to loose network configuration due to NIC being renamed to actually used topology. That also restricts freedom to reshape PCI configuration of VM without need to reconfigure used guest image. systemd also offers "onboard" naming scheme which is preferred over PCI slot/topology one, provided that firmware implements: " PCI Firmware Specification 3.1 4.6.7. DSM for Naming a PCI or PCI Express Device Under Operating Systems " that allows to assign user defined index to PCI device, which systemd will use to name NIC. For example, using -device e1000,acpi-index=100 guest will rename NIC to 'eno100', where 'eno' is default prefix for "onboard" naming scheme. This doesn't require any advance configuration on guest side to com in effect at 'onboard' scheme takes priority over path based naming. Hope is that 'acpi-index' it will be easier to consume by management layer, compared to forcing specific PCI topology and/or having several disk image templates for different topologies and will help to simplify process of spawning VM from the same template without need to reconfigure guest NIC. This patch adds, 'acpi-index'* property and wires up a 32bit register on top of pci hotplug register block to pass index value to AML code at runtime. Following patch will add corresponding _DSM code and wire it up to PCI devices described in ACPI. *) name comes from linux kernel terminology Signed-off-by:Igor Mammedov <imammedo@redhat.com> Message-Id: <20210315180102.3008391-3-imammedo@redhat.com> Reviewed-by:
Michael S. Tsirkin <mst@redhat.com> Signed-off-by:
b32bd763
