31. LiquidIO VF Poll Mode Driver

The LiquidIO VF PMD library (librte_pmd_lio) provides poll mode driver support for Cavium LiquidIO® II server adapter VFs. PF management and VF creation can be done using kernel driver.

More information can be found at Cavium Official Website.

31.1. Supported LiquidIO Adapters

LiquidIO II CN2350 210SV/225SV
LiquidIO II CN2350 210SVPT
LiquidIO II CN2360 210SV/225SV
LiquidIO II CN2360 210SVPT

31.2. Pre-Installation Configuration

The following options can be modified in the config file. Please note that enabling debugging options may affect system performance.

CONFIG_RTE_LIBRTE_LIO_PMD (default y)

Toggle compilation of LiquidIO PMD.
CONFIG_RTE_LIBRTE_LIO_DEBUG_RX (default n)

Toggle display of receive fast path run-time messages.
CONFIG_RTE_LIBRTE_LIO_DEBUG_TX (default n)

Toggle display of transmit fast path run-time messages.
CONFIG_RTE_LIBRTE_LIO_DEBUG_MBOX (default n)

Toggle display of mailbox messages.
CONFIG_RTE_LIBRTE_LIO_DEBUG_REGS (default n)

Toggle display of register reads and writes.

31.3. SR-IOV: Prerequisites and Sample Application Notes

This section provides instructions to configure SR-IOV with Linux OS.

Verify SR-IOV and ARI capabilities are enabled on the adapter using lspci:

lspci -s <slot> -vvv

Example output:

[...]
Capabilities: [148 v1] Alternative Routing-ID Interpretation (ARI)
[...]
Capabilities: [178 v1] Single Root I/O Virtualization (SR-IOV)
[...]
Kernel driver in use: LiquidIO

Load the kernel module:
```
modprobe liquidio
```
Bring up the PF ports:
```
ifconfig p4p1 up
ifconfig p4p2 up
```

Change PF MTU if required:

ifconfig p4p1 mtu 9000
ifconfig p4p2 mtu 9000

Create VF device(s):

Echo number of VFs to be created into "sriov_numvfs" sysfs entry of the parent PF.

echo 1 > /sys/bus/pci/devices/0000:03:00.0/sriov_numvfs
echo 1 > /sys/bus/pci/devices/0000:03:00.1/sriov_numvfs

Assign VF MAC address:

Assign MAC address to the VF using iproute2 utility. The syntax is:
```
ip link set <PF iface> vf <VF id> mac <macaddr>
```
Example output:
```
ip link set p4p1 vf 0 mac F2:A8:1B:5E:B4:66
```

Assign VF(s) to VM.

The VF devices may be passed through to the guest VM using qemu or virt-manager or virsh etc.

Example qemu guest launch command:

./qemu-system-x86_64 -name lio-vm -machine accel=kvm \
-cpu host -m 4096 -smp 4 \
-drive file=<disk_file>,if=none,id=disk1,format=<type> \
-device virtio-blk-pci,scsi=off,drive=disk1,id=virtio-disk1,bootindex=1 \
-device vfio-pci,host=03:00.3 -device vfio-pci,host=03:08.3

Running testpmd

Refer to the document compiling and testing a PMD for a NIC to run testpmd application.

Note

Use igb_uio instead of vfio-pci in VM.

Example output:

[...]
EAL: PCI device 0000:03:00.3 on NUMA socket 0
EAL:   probe driver: 177d:9712 net_liovf
EAL:   using IOMMU type 1 (Type 1)
PMD: net_liovf[03:00.3]INFO: DEVICE : CN23XX VF
EAL: PCI device 0000:03:08.3 on NUMA socket 0
EAL:   probe driver: 177d:9712 net_liovf
PMD: net_liovf[03:08.3]INFO: DEVICE : CN23XX VF
Interactive-mode selected
USER1: create a new mbuf pool <mbuf_pool_socket_0>: n=171456, size=2176, socket=0
Configuring Port 0 (socket 0)
PMD: net_liovf[03:00.3]INFO: Starting port 0
Port 0: F2:A8:1B:5E:B4:66
Configuring Port 1 (socket 0)
PMD: net_liovf[03:08.3]INFO: Starting port 1
Port 1: 32:76:CC:EE:56:D7
Checking link statuses...
Port 0 Link Up - speed 10000 Mbps - full-duplex
Port 1 Link Up - speed 10000 Mbps - full-duplex
Done
testpmd>

Enabling VF promiscuous mode

One VF per PF can be marked as trusted for promiscuous mode.
```
ip link set dev <PF iface> vf <VF id> trust on
```

31.4. Limitations

31.4.1. VF MTU

VF MTU is limited by PF MTU. Raise PF value before configuring VF for larger packet size.

31.4.2. VLAN offload

Tx VLAN insertion is not supported and consequently VLAN offload feature is marked partial.

31.4.3. Ring size

Number of descriptors for Rx/Tx ring should be in the range 128 to 512.

31.4.4. CRC stripping

LiquidIO adapters strip ethernet FCS of every packet coming to the host interface.