OVS Offload Using ASAP² Direct
Supported on ConnectX-5 and above adapter cards.
Open vSwitch (OVS) allows Virtual Machines (VMs) to communicate with each other and with the outside world. OVS traditionally resides in the hypervisor and switching is based on twelve tuple matching on flows. The OVS software based solution is CPU intensive, affecting system performance and preventing full utilization of the available bandwidth.
NVIDIA Accelerated Switching And Packet Processing (ASAP2) technology allows OVS offloading by handling OVS data-plane in ConnectX-5 onwards NIC hardware (Embedded Switch or eSwitch) while maintaining OVS control-plane unmodified. As a result, we observe significantly higher OVS performance without the associated CPU load.
As of v5.0, OVS-DPDK became part ofMLNX_OFED package. OVS-DPDK supports ASAP2 just as the OVS-Kernel (Traffic Control (TC) kernel-based solution) does, yet with a different set of features.
The traditional ASAP2 hardware data plane is built over SR-IOV virtual functions (VFs), so that the VF is passed through directly to the VM, with the NVIDIA driver running within the VM. An alternate approach that is also supported is vDPA (vhost Data Path Acceleration). vDPA allows the connection to the VM to be established using VirtIO, so that the data-plane is built between the SR-IOV VF and the standard VirtIO driver within the VM, while the control-plane is managed on the host by the vDPA application. Two flavors of vDPA are supported, Software vDPA; and Hardware vDPA. Software vDPA management functionality is embedded into OVS-DPDK, while Hardware vDPA uses a standalone application for management, and can be run with both OVS-Kernel and OVS-DPDK. For further information, please see sections VirtIO Acceleration through VF Relay (Software vDPA) and VirtIO Acceleration through Hardware vDPA.
Install the required packages. For the complete solution, you need to install supporting MLNX_OFED(v4.4 and above), iproute2, and openvswitch packages.
Run:
./mlnxofedinstall --ovs-dpdk –upstream-libs
Note that this section applies to both OVS-DPDK and OVS-Kernel similarly.
To set up SR-IOV:
Choose the desired card.
The example below shows a dual-ported ConnectX-5 card (device ID 0x1017) and a single SR-IOV VF (Virtual Function, device ID 0x1018).
In SR-IOV terms, the card itself is referred to as the PF (Physical Function).
# lspci -nn | grep Mellanox 0a:
00.0Ethernet controller [0200]: Mellanox Technologies MT27800 Family [ConnectX-5] [15b3:1017] 0a:00.1Ethernet controller [0200]: Mellanox Technologies MT27800 Family [ConnectX-5] [15b3:1017] 0a:00.2Ethernet controller [0200]: Mellanox Technologies MT27800 Family [ConnectX-5Virtual Function] [15b3:1018]WarningEnabling SR-IOV and creating VFs is done by the firmware upon admin directive as explained in Step 5 below.
Identify the NVIDIA NICs and locate net-devices which are on the NIC PCI BDF.
# ls -l /sys/
class/net/ | grep04:00lrwxrwxrwx1root root0Mar2716:58enp4s0f0 -> ../../devices/pci0000:00/0000:00:03.0/0000:04:00.0/net/enp4s0f0 lrwxrwxrwx1root root0Mar2716:58enp4s0f1 -> ../../devices/pci0000:00/0000:00:03.0/0000:04:00.1/net/enp4s0f1 lrwxrwxrwx1root root0Mar2716:58eth0 -> ../../devices/pci0000:00/0000:00:03.0/0000:04:00.2/net/eth0 lrwxrwxrwx1root root0Mar2716:58eth1 -> ../../devices/pci0000:00/0000:00:03.0/0000:04:00.3/net/eth1The PF NIC for port #1 is enp4s0f0, and the rest of the commands will be issued on it.
Check the firmware version.
Make sure the firmware versions installed are as state in the Release Notes document.# ethtool -i enp4s0f0 | head -
5driver: mlx5_core version:5.0-5firmware-version:16.21.0338expansion-rom-version: bus-info:0000:04:00.0Make sure SR-IOV is enabled on the system (server, card).
Make sure SR-IOV is enabled by the server BIOS, and by the firmware with up to N VFs, where N is the number of VFs required for your environment. Refer to "NVIDIA Firmware Tools" below for more details.# cat /sys/
class/net/enp4s0f0/device/sriov_totalvfs4Turn ON SR-IOV on the PF device.
# echo
2> /sys/class/net/enp4s0f0/device/sriov_numvfsProvision the VF MAC addresses using the IP tool.
# ip link set enp4s0f0 vf
0mac e4:11:22:33:44:50# ip link set enp4s0f0 vf1mac e4:11:22:33:44:51Verify the VF MAC addresses were provisioned correctly and SR-IOV was turned ON.
# cat /sys/
class/net/enp4s0f0/device/sriov_numvfs2# ip link show dev enp4s0f0256: enp4s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu1500qdisc mq master ovs-system state UP mode DEFAULT groupdefaultqlen1000link/ether e4:1d:2d:60:95:a0 brd ff:ff:ff:ff:ff:ff vf0MAC e4:11:22:33:44:50, spoof checking off, link-state auto vf1MAC e4:11:22:33:44:51, spoof checking off, link-state autoIn the example above, the maximum number of possible VFs supported by the firmware is 4 and only 2 are enabled.
Provision the PCI VF devices to VMs using PCI Pass-Through or any other preferred virt tool of choice, e.g virt-manager.
For further information on SR-IOV, refer to HowTo Configure SR-IOV for ConnectX-4/ConnectX-5/ConnectX-6 with KVM (Ethernet).
OVS-Kernel Hardware Offloads
SwitchDev Configuration
Unbind the VFs.
echo
0000:04:00.2> /sys/bus/pci/drivers/mlx5_core/unbind echo0000:04:00.3> /sys/bus/pci/drivers/mlx5_core/unbindWarningVMs with attached VFs must be powered off to be able to unbind the VFs.
Change the eSwitch mode from Legacy to SwitchDev on the PF device.
This will also create the VF representor netdevices in the host OS.# devlink dev eswitch set pci/
0000:3b:00.0mode switchdevWarningBefore changing the mode, make sure that all VFs are unbound.
WarningTo go back to SR-IOV legacy mode, run:
# devlink dev eswitch set pci/0000:3b:00.0 mode legacy
This will also remove the VF representor netdevices.On old OSs or kernels that do not support Devlink, moving to SwitchDev mode can be done using sysfs.
# echo switchdev > /sys/
class/net/enp4s0f0/compat/devlink/modeAt this stage, VF representors have been created. To map representor to its VF, make sure to obtain the representor's switchid and portname from:
# ip -d link show eth4
41: enp0s8f0_1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu1500qdisc mq state UP mode DEFAULT groupdefaultqlen1000link/ether ba:e6:21:37:bc:d4 brd ff:ff:ff:ff:ff:ff promiscuity0addrgenmode eui64 numtxqueues10numrxqueues10gso_max_size65536gso_max_segs65535portname pf0vf1 switchid f4ab580003a1420cswitchid - used to map representor to device, both device PFs have the same switchid.
portname - used to map representor to PF and VF, value returned is pfXvfY, where X is the PF number and Y is the number of VF.
On old kernels, switchid and portname can be acquired through sysfs:Bind the VFs.
echo
0000:04:00.2> /sys/bus/pci/drivers/mlx5_core/bind echo0000:04:00.3> /sys/bus/pci/drivers/mlx5_core/bind
SwitchDev Performance Tuning
SwitchDev performance can be further improved by tuning it.
Steering Mode
OVS-kernel supports two steering modes for rules insertion into hardware.
SMFS – Software Managed Flow Steering (as of MLNX_OFED v5.1, this is the default mode)
Rules are inserted directly to the hardware by the software (driver). This mode is optimized for rules insertion.
DMFS – Device Managed Flow Steering
Rules insertion is done using firmware commands. This mode is optimized for throughput with a small amount of rules in the system.
The mode can be controlled via sysfs or devlink API in kernels that support it:
Sysfs: # echo smfs > /sys/
class/net/<PF netdev>/compat/devlink/steering_mode Devlink: # devlink dev param set pci/0000:00:08.0name flow_steering_mode value"smfs"cmode runtime Replace smfs param with dmfsfordevice managed flow steering
Notes:
The mode should be set prior to moving to SwitchDev, by echoing to the sysfs or invoking the devlink command.
Only when moving to SwitchDev will the driver use the mode set by the previous step.
Mode cannot be changed after moving to SwitchDev.
The steering mode is applicable for SwitchDev mode only, meaning it does not affect legacy SR-IOV or other configurations.
Troubleshooting SMFS
mlx5 debugfs was extended to support presenting Software Steering resources:
dr_domain including it's tables, matchers and rules.
The interface is read-only.
While dump is being created, new steering rules cannot be inserted/deleted.
The steering information is dumped in the CSV form with the following format: <object_type>,<object_ID>, <object_info>,...,<object_info>
This data can be read at the following path: /sys/kernel/debug/mlx5/<BDF>/steering/fdb/<domain_handle>
Example:
# cat /sys/kernel/debug/mlx5/0000:82:00.0/steering/fdb/dmn_000018644
3100,0x55caa4621c50,0xee802,4,65533
3101,0x55caa4621c50,0xe0100008
You can then use the steering dump parser to make the output more human readable.
The parser can be found in the following public GitHub repository:
https://github.com/Mellanox/mlx_steering_dump
vPort Match Mode
OVS-kernel support two modes that define how the rules on match on vport.
Metadata – rules match on metadata instead of vport number (default mode).
This mode is needed in order to support SR-IOV Live migration and Dual port RoCE features.
Matching on Metadata can have a performance impact.
Legacy – rules match on vport number.
In this mode, performance can be higher in comparison to Metadata. It can still be used only if none of the above features (SR-IOV Live migration and Dual port RoCE) is enabled/used.
The mode can be controlled via sysfs:
Set Legacy: # echo legacy > /sys/
class/net/<PF netdev>/compat/devlink/vport_match_mode Set metadata: Devlink: # echo metadata > /sys/class/net/<PF netdev>/compat/devlink/vport_match_modeNote: This mode should be set prior to moving to SwitchDev, by echoing to the sysfs.
Flow Table Large Group Number
Offloaded flows, including Connection Tracking, are added to Virtual Switch Forwarding Data Base (FDB) flow tables. FDB tables have a set of flow groups, where each flow group saves the same traffic pattern flows. E.g, for connection tracking offloaded flow, TCP and UDP are different traffic patterns which will end up in two different flow groups.
A flow group has a limited size to save flow entries. As default, the driver has 15 big FDB flow groups. Each of these big flow groups can save 4M / ( 15 + 1) = 256k different 5-tuple flow entries at most. For scenarios with more than 15 traffic patterns, the driver provides a module parameter (num_of_groups) to allow customization and performance tuning.
The mode can be controlled via module param or devlink API for kernels that support it:
Module param:
# echo <num_of_groups> > /sys/module/mlx5_core/parameters/num_of_groups
Devlink:
# devlink dev param set pci/0000:82:00.0 name fdb_large_groups \
cmode driverinit value 20
Notes:
In MLNX_OFED v5.1, the default value was changed from 4 to 15.
The change takes effect immediately if there is no flow inside the FDB table (no traffic running and all offloaded flows are aged out). And it can be dynamically changed without reloading the driver.
If there are still offloaded flows residual when changing this parameter, it will only take effect after all flows have aged out.
Open vSwitch Configuration
Open vSwitch configuration is a simple OVS bridge configuration with SwitchDev.
Run the openvswitch service.
# systemctl start openvswitch
Create an OVS bridge (here it's named ovs-sriov).
# ovs-vsctl add-br ovs-sriov
Enable hardware offload (disabled by default).
# ovs-vsctl set Open_vSwitch . other_config:hw-offload=
trueRestart the openvswitch service. This step is required for HW offload changes to take effect.
# systemctl restart openvswitch
WarningHW offload policy can also be changed by setting the tc-policy using one on the following values:
* none - adds a TC rule to both the software and the hardware (default)
* skip_sw - adds a TC rule only to the hardware
* skip_hw - adds a TC rule only to the software
The above change is used for debug purposes.
Add the PF and the VF representor netdevices as OVS ports.
# ovs-vsctl add-port ovs-sriov enp4s0f0 # ovs-vsctl add-port ovs-sriov enp4s0f0_0 # ovs-vsctl add-port ovs-sriov enp4s0f0_1
Make sure to bring up the PF and representor netdevices.
# ip link set dev enp4s0f0 up # ip link set dev enp4s0f0_0 up # ip link set dev enp4s0f0_1 up
The PF represents the uplink (wire).
# ovs-dpctl show system
@ovs-system: lookups: hit:0missed:192lost:1flows:2masks: hit:384total:2hit/pkt:2.00port0: ovs-system (internal) port1: ovs-sriov (internal) port2: enp4s0f0 port3: enp4s0f0_0 port4: enp4s0f0_1Run traffic from the VFs and observe the rules added to the OVS data-path.
# ovs-dpctl dump-flows recirc_id(
0),in_port(3),eth(src=e4:11:22:33:44:50,dst=e4:1d:2d:a5:f3:9d), eth_type(0x0800),ipv4(frag=no), packets:33, bytes:3234, used:1.196s, actions:2recirc_id(0),in_port(2),eth(src=e4:1d:2d:a5:f3:9d,dst=e4:11:22:33:44:50), eth_type(0x0800),ipv4(frag=no), packets:34, bytes:3332, used:1.196s, actions:3In the example above, the ping was initiated from VF0 (OVS port 3) to the outer node (OVS port 2), where the VF MAC is e4:11:22:33:44:50 and the outer node MAC is e4:1d:2d:a5:f3:9d
As shown above, two OVS rules were added, one in each direction.
Note that you can also verify offloaded packets by adding type=offloaded to the command. For example:# ovs-appctl dpctl/dump-flows type=offloaded
Open vSwitch Performance Tuning
Flow Aging
The aging timeout of OVS is given in ms and can be controlled using the following command.
# ovs-vsctl set Open_vSwitch . other_config:max-idle=30000
TC Policy
Specifies the policy used with HW offloading.
none - adds a TC rule to both the software and the hardware (default)
skip_sw - adds a TC rule only to the hardware
skip_hw - adds a TC rule only to the software
Example:
# ovs-vsctl set Open_vSwitch . other_config:tc-policy=skip_sw
Note: TC policy should only be used for debugging purposes.
Max-Revalidator
Specifies the maximum time (in ms) that revalidator threads will wait for kernel statistics before executing flow revalidation.
# ovs-vsctl set Open_vSwitch . other_config:max-revalidator=10000
n-handler-threads
Specifies the number of threads for software datapaths to use for handling new flows.
The default value is the number of online CPU cores minus the number of revalidators.
# ovs-vsctl set Open_vSwitch . other_config:n-handler-threads=4
n-revalidator-threads
Specifies the number of threads for software datapaths to use for revalidating flows in the datapath.
# ovs-vsctl set Open_vSwitch . other_config:n-revalidator-threads=4
vlan-limit
Limits the number of VLAN headers that can be matched to the specified number.
# ovs-vsctl set Open_vSwitch . other_config:vlan-limit=2
Basic TC Rules Configuration
Offloading rules can also be added directly, and not only through OVS, using the tc utility.
To create an offloading rule using TC:
Create an ingress qdisc (queueing discipline) for each interface that you wish to add rules into.
# tc qdisc add dev enp4s0f0 ingress # tc qdisc add dev enp4s0f0_0 ingress # tc qdisc add dev enp4s0f0_1 ingress
Add TC rules using flower classifier in the following format.
# tc filter add dev NETDEVICE ingress protocol PROTOCOL prio PRIORITY \ [chain CHAIN] flower [ MATCH_LIST ] [ action ACTION_SPEC ]
Note: List of supported matches (specifications) and actions can be found in Classification Fields (Matches) section.
Dump the existing tc rules using flower classifier in the following format.
# tc [ -s ] filter show dev NETDEVICE ingress
SR-IOV VF LAG
SR-IOV VF LAG allows the NIC’s physical functions (PFs) to get the rules that the OVS will try to offload to the bond net-device, and to offload them to the hardware e-switch. Bond modes supported are:
Active-Backup
XOR
LACP
SR-IOV VF LAG enables complete offload of the LAG functionality to the hardware. The bonding creates a single bonded PF port. Packets from up-link can arrive from any of the physical ports, and will be forwarded to the bond device.
When hardware offload is used, packets from both ports can be forwarded to any of the VFs. Traffic from the VF can be forwarded to both ports according to the bonding state. Meaning, when in active-backup mode, only one PF is up, and traffic from any VF will go through this PF. When in XOR or LACP mode, if both PFs are up, traffic from any VF will split between these two PFs.
SR-IOV VF LAG Configuration on ASAP2
To enable SR-IOV VF LAG, both physical functions of the NIC should first be configured to SR-IOV SwitchDev mode, and only afterwards bond the up-link representors.
The example below shows the creation of bond interface on two PFs:
Load bonding device and enslave the up-link representor (currently PF) net-device devices.
modprobe bonding mode=
802.3ad Ifup bond0 (make sure ifcfg file is present with desired bond configuration) ip link set enp4s0f0 master bond0 ip link set enp4s0f1 master bond0Add the VF representor net-devices as OVS ports. If tunneling is not used, add the bond device as well.
ovs-vsctl add-port ovs-sriov bond0 ovs-vsctl add-port ovs-sriov enp4s0f0_0 ovs-vsctl add-port ovs-sriov enp4s0f1_0
Make sure to bring up the PF and the representor netdevices.
ip link set dev bond0 up ip link set dev enp4s0f0_0 up ip link set dev enp4s0f1_0 up
Once SR-IOV VF LAG is configured, all VFs of the two PFs will become part of the bond, and will behave as described above.
Limitations
In VF LAG mode, outgoing traffic in load balanced mode is according to the origin ring, thus, half of the rings will be coupled with port 1 and half with port 2. All the traffic on the same ring will be sent from the same port.
VF LAG configuration is not supported when the NUM_OF_VFS configured in mlxconfig is higher than 64.
Using TC with VF LAG
Both rules can be added using either of the following.
Shared block (supported from kernel 4.16 and RHEL/CentOS 7.7 and above).
# tc qdisc add dev bond0 ingress_block
22ingress # tc qdisc add dev ens4p0 ingress_block22ingress # tc qdisc add dev ens4p1 ingress_block22ingressAdd drop rule.
# tc filter add block
22protocol arp parent ffff: prio3\ flower \ dst_mac e4:11:22:11:4a:51\ action dropAdd redirect rule from bond to representor.
# tc filter add block
22protocol arp parent ffff: prio3\ flower \ dst_mac e4:11:22:11:4a:50\ action mirred egress redirect dev ens4f0_0Add redirect rule from representor to bond.
# tc filter add dev ens4f0_0 protocol arp parent ffff: prio
3\ flower \ dst_mac ec:0d:9a:8a:28:42\ action mirred egress redirect dev bond0
Without shared block (supported from kernel 4.15 and below).
Add redirect rule from bond to representor.
# tc filter add dev bond0 protocol arp parent ffff: prio
1\ flower \ dst_mac e4:11:22:11:4a:50\ action mirred egress redirect dev ens4f0_0Add redirect rule from representor to bond.
# tc filter add dev ens4f0_0 protocol arp parent ffff: prio
3\ flower \ dst_mac ec:0d:9a:8a:28:42\ action mirred egress redirect dev bond0
Classification Fields (Matches)
OVS-Kernel supports multiple classification fields which packets can fully or partially match.
Ethernet Layer 2
Destination MAC
Source MAC
Ethertype
Supported on all kernels.
In OVS dump flows:
skb_priority(0/0),skb_mark(0/0),in_port(eth6),eth(src=00:02:10:40:10:0d
,dst=68:54:ed:00:af:de),eth_type(0x8100), packets:1981, bytes:206024, used:0.440s, dp:tc, actions:eth7
Using TC rules:
tc filter add dev $rep parent ffff: protocol arp pref 1 \
flower \
dst_mac e4:1d:2d:5d:25:35 \
src_mac e4:1d:2d:5d:25:34 \
action mirred egress redirect dev $NIC
IPv4/IPv6
Source address
Destination address
Protocol
TCP/UDP/ICMP/ICMPv6
TOS
TTL (HLIMIT)
Supported on all kernels.
In OVS dump flows:
Ipv4:
ipv4(src=0.0.0.0/0.0.0.0,dst=0.0.0.0/0.0.0.0,proto=17,tos=0/0,ttl=0/0,frag=no)
Ipv6:
ipv6(src=::/::,dst=1:1:1::3:1040:1008,label=0/0,proto=58,tclass=0/0x3,hlimit=64),
Using TC rules:
IPv4:
tc filter add dev $rep parent ffff: protocol ip pref 1 \
flower \
dst_ip 1.1.1.1 \
src_ip 1.1.1.2 \
ip_proto TCP \
ip_tos 0x3 \
ip_ttl 63 \
action mirred egress redirect dev $NIC
IPv6:
tc filter add dev $rep parent ffff: protocol ipv6 pref 1 \
flower \
dst_ip 1:1:1::3:1040:1009 \
src_ip 1:1:1::3:1040:1008 \
ip_proto TCP \
ip_tos 0x3 \
ip_ttl 63\
action mirred egress redirect dev $NIC
TCP/UDP Source and Destination ports & TCP Flags
TCP/UDP source and destinations ports
TCP flags
Supported kernels are kernel > 4.13 and RHEL > 7.5
In OVS dump flows:
TCP: tcp(src=0/0,dst=32768/0x8000),
UDP: udp(src=0/0,dst=32768/0x8000),
TCP flags: tcp_flags(0/0)
Using TC rules:
tc filter add dev $rep parent ffff: protocol ip pref 1 \
flower \
ip_proto TCP \
dst_port 100 \
src_port 500 \
tcp_flags 0x4/0x7 \
action mirred egress redirect dev $NIC
VLAN
ID
Priority
Inner vlan ID and Priority
Supported kernels: All (QinQ: kernel 4.19 and higher, and RHEL 7.7 and higher)
In OVS dump flows:
eth_type(0x8100),vlan(vid=2347,pcp=0),
Using TC rules:
tc filter add dev $rep parent ffff: protocol 802.1Q pref 1 \
flower \
vlan_ethtype 0x800 \
vlan_id 100 \
vlan_prio 0 \
action mirred egress redirect dev $NIC
QinQ:
tc filter add dev $rep parent ffff: protocol 802.1Q pref 1 \
flower \
vlan_ethtype 0x8100 \
vlan_id 100 \
vlan_prio 0 \
cvlan_id 20 \
cvlan_prio 0 \
cvlan_ethtype 0x800 \
action mirred egress redirect dev $NIC
Tunnel
ID (Key)
Source IP address
Destination IP address
Destination port
TOS (supported from kernel 4.19 and above & RHEL 7.7 and above)
TTL (support from kernel 4.19 and above & RHEL 7.7 and above)
Tunnel options (Geneve)
Supported kernels:
VXLAN: All
GRE: Kernel > 5.0, RHEL 7.7 and above
Geneve: Kernel > 5.0, RHEL 7.7 and above
In OVS dump flows:
tunnel(tun_id=0x5,src=121.9.1.1,dst=131.10.1.1,ttl=0/0,tp_dst=4789,flags(+key))
Using TC rules:
# tc filter add dev $rep protocol 802.1Q parent ffff: pref 1
flower \
vlan_ethtype 0x800 \
vlan_id 100 \
vlan_prio 0 \
action mirred egress redirect dev $NIC
QinQ:
# tc filter add dev vxlan100 protocol ip parent ffff: \
flower \
skip_sw \
dst_mac e4:11:22:11:4a:51 \
src_mac e4+:11:22:11:4a:50 \
enc_src_ip 20.1.11.1 \
enc_dst_ip 20.1.12.1 \
enc_key_id 100 \
enc_dst_port 4789 \
action tunnel_key unset \
action mirred egress redirect dev ens4f0_0
Supported Actions
Forward
Forward action allows for packet redirection:
From VF to wire
Wire to VF
VF to VF
Supported on all kernels.
In OVS dump flows:
skb_priority(0/0),skb_mark(0/0),in_port(eth6),eth(src=00:02:10:40:10:0d
,dst=68:54:ed:00:af:de),eth_type(0x8100), packets:1981, bytes:206024, used:0.440s, dp:tc, actions:eth7
Using TC rules:
tc filter add dev $rep parent ffff: protocol arp pref 1 \
flower \
dst_mac e4:1d:2d:5d:25:35 \
src_mac e4:1d:2d:5d:25:34 \
action mirred egress redirect dev $NIC
Drop
Drop action allows to drop incoming packets.
Supported on all kernels.
In OVS dump flows:
skb_priority(0/0),skb_mark(0/0),in_port(eth6),eth(src=00:02:10:40:10:0d
,dst=68:54:ed:00:af:de),eth_type(0x8100), packets:1981, bytes:206024, used:0.440s, dp:tc, actions:drop
Using TC rules:
tc filter add dev $rep parent ffff: protocol arp pref 1 \
flower \
dst_mac e4:1d:2d:5d:25:35 \
src_mac e4:1d:2d:5d:25:34 \
action drop
Statistics
By default, each flow collects the following statistics:
Packets – number of packets which hit the flow
Bytes – total number of bytes which hit the flow
Last used – the amount of time passed since last packet hit the flow
Supported on all kernels.
In OVS dump flows:
skb_priority(0/0),skb_mark(0/0),in_port(eth6),eth(src=00:02:10:40:10:0d
,dst=68:54:ed:00:af:de),eth_type(0x8100), packets:1981, bytes:206024, used:0.440s, dp:tc, actions:drop
Using TC rules:
#tc -s filter show dev $rep ingress
filter protocol ip pref 2 flower chain 0
filter protocol ip pref 2 flower chain 0 handle 0x2
eth_type ipv4
ip_proto tcp
src_ip 192.168.140.100
src_port 80
skip_sw
in_hw
action order 1: mirred (Egress Redirect to device p0v11_r) stolen
index 34 ref 1 bind 1 installed 144 sec used 0 sec
Action statistics:
Sent 388344 bytes 2942 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
Tunnels (Encapsulation/Decapsulation)
OVS-kernel supports offload of tunnels using encapsulation and decapsulation actions.
Encapsulation – pushing of tunnel header is supported on Tx
Decapsulation – popping of tunnel header is supported on Rx
Supported Tunnels:
VXLAN (IPv4/IPv6) – supported on all Kernels
GRE (IPv4/IPv6) – supported on kernel 5.0 and above & RHEL 7.6 and above
Geneve (IPv4/IPv6) - supported on kernel 5.0 and above & RHEL 7.6 and above
OVS configuration:
In case of offloading tunnel, the PF/bond should not be added as a port in the OVS datapath. It should rather be assigned with the IP address to be used for encapsulation.
The example below shows two hosts (PFs) with IPs 1.1.1.177 and 1.1.1.75, where the PF device on both hosts is enp4s0f0, and the VXLAN tunnel is set with VNID 98:
On the first host:
# ip addr add
1.1.1.177/24dev enp4s0f1 # ovs-vsctl add-port ovs-sriov vxlan0 -- setinterfacevxlan0 type=vxlan options:local_ip=1.1.1.177options:remote_ip=1.1.1.75options:key=98On the second host:
# ip addr add
1.1.1.75/24dev enp4s0f1 # ovs-vsctl add-port ovs-sriov vxlan0 -- setinterfacevxlan0 type=vxlan options:local_ip=1.1.1.75options:remote_ip=1.1.1.177options:key=98•forGRE IPv4 tunnel need use type=gre •forGRE IPv6 tunnel need use type=ip6gre •forGENEVE tunnel need use type=geneve
When encapsulating guest traffic, the VF’s device MTU must be reduced to allow the host/HW to add the encap headers without fragmenting the resulted packet. As such, the VF’s MTU must be lowered by 50 bytes from the uplink MTU for IPv4 and 70 bytes for IPv6.
Tunnel offload using TC rules:
Encapsulation:
# tc filter add dev ens4f0_0 protocol 0x806 parent ffff: \
flower \
skip_sw \
dst_mac e4:11:22:11:4a:51 \
src_mac e4:11:22:11:4a:50 \
action tunnel_key set \
src_ip 20.1.12.1 \
dst_ip 20.1.11.1 \
id 100 \
action mirred egress redirect dev vxlan100
Decapsulation:
# tc filter add dev vxlan100 protocol 0x806 parent ffff: \
flower \
skip_sw \
dst_mac e4:11:22:11:4a:51 \
src_mac e4:11:22:11:4a:50 \
enc_src_ip 20.1.11.1 \
enc_dst_ip 20.1.12.1 \
enc_key_id 100 \
enc_dst_port 4789 \
action tunnel_key unset \
action mirred egress redirect dev ens4f0_0
VLAN Push/Pop
OVS-kernel supports offload of VLAN header push/pop actions.
Push—pushing of VLAN header is supported on Tx
Pop—popping of tunnel header is supported on Rx
Starting with ConnectX-6 Dx hardware models and above, pushing of VLAN header is also supported on Rx, and popping of VLAN header is also supported on Tx.
OVS Configuration
Add a tag=$TAG section for the OVS command line that adds the representor ports. For example, VLAN ID 52 is being used here.
# ovs-vsctl add-port ovs-sriov enp4s0f0
# ovs-vsctl add-port ovs-sriov enp4s0f0_0 tag=52
# ovs-vsctl add-port ovs-sriov enp4s0f0_1 tag=52
The PF port should not have a VLAN attached. This will cause OVS to add VLAN push/pop actions when managing traffic for these VFs.
Dump Flow Example
recirc_id(0),in_port(3),eth(src=e4:11:22:33:44:50,dst=00:02:c9:e9:bb:b2),eth_type(0x0800),ipv4(frag=no), \
packets:0, bytes:0, used:never, actions:push_vlan(vid=52,pcp=0),2
recirc_id(0),in_port(2),eth(src=00:02:c9:e9:bb:b2,dst=e4:11:22:33:44:50),eth_type(0x8100), \
vlan(vid=52,pcp=0),encap(eth_type(0x0800),ipv4(frag=no)), packets:0, bytes:0, used:never, actions:pop_vlan,3
VLAN Offload using TC Rules Example
# tc filter add dev ens4f0_0 protocol ip parent ffff: \
flower \
skip_sw \
dst_mac e4:11:22:11:4a:51 \
src_mac e4:11:22:11:4a:50 \
action vlan push id 100 \
action mirred egress redirect dev ens4f0
# tc filter add dev ens4f0 protocol 802.1Q parent ffff: \
flower \
skip_sw \
dst_mac e4:11:22:11:4a:51 \
src_mac e4:11:22:11:4a:50 \
vlan_ethtype 0x800 \
vlan_id 100 \
vlan_prio 0 \
action vlan pop \
action mirred egress redirect dev ens4f0_0
TC Configuration for ConnectX-6 Dx and Above
Example of VLAN Offloading with popping header on Tx and pushing on Rx using TC Rules:
# tc filter add dev ens4f0_0 ingress protocol 802.1Q parent ffff: \
flower \
vlan_id 100 \
action vlan pop \
action tunnel_key set \
src_ip 4.4.4.1 \
dst_ip 4.4.4.2 \
dst_port 4789 \
id 42 \
action mirred egress redirect dev vxlan0
# tc filter add dev vxlan0 ingress protocol all parent ffff: \
flower \
enc_dst_ip 4.4.4.1 \
enc_src_ip 4.4.4.2 \
enc_dst_port 4789 \
enc_key_id 42 \
action tunnel_key unset \
action vlan push id 100 \
action mirred egress redirect dev ens4f0_0
Header Rewrite
This action allows for modifying packet fields.
Ethernet Layer 2
Destination MAC
Source MAC
Supported kernels: Kernel 4.14 and above & RHEL 7.5 and above
In OVS dump flows:
skb_priority(0/0),skb_mark(0/0),in_port(eth6),eth(src=00:02:10:40:10:0d
,dst=68:54:ed:00:af:de),eth_type(0x8100), packets:1981, bytes:206024, used:0.440s, dp:tc, actions: set(eth(src=68:54:ed:00:f4:ab,dst=fa:16:3e:dd:69:c4)),eth7
Using TC rules:
tc filter add dev $rep parent ffff: protocol arp pref 1 \
flower \
dst_mac e4:1d:2d:5d:25:35 \
src_mac e4:1d:2d:5d:25:34 \
action pedit ex \
munge eth dst set 20:22:33:44:55:66 \
munge eth src set aa:ba:cc:dd:ee:fe \
action mirred egress redirect dev $NIC
IPv4/IPv6
Source address
Destination address
Protocol
TOS
TTL (HLIMIT)
Supported kernels: Kernel 4.14 and above & RHEL 7.5 and above
In OVS dump flows:
Ipv4:
set(eth(src=de:e8:ef:27:5e:45,dst=00:00:01:01:01:01)),
set(ipv4(src=10.10.0.111,dst=10.20.0.122,ttl=63))
Ipv6:
set(ipv6(dst=2001:1:6::92eb:fcbe:f1c8,hlimit=63)),
Using TC rules:
IPv4:
tc filter add dev $rep parent ffff: protocol ip pref 1 \
flower \
dst_ip 1.1.1.1 \
src_ip 1.1.1.2 \
ip_proto TCP \
ip_tos 0x3 \
ip_ttl 63 \
pedit ex \
munge ip src set 2.2.2.1 \
munge ip dst set 2.2.2.2 \
munge ip tos set 0 \
munge ip ttl dec \
action mirred egress redirect dev $NIC
IPv6:
tc filter add dev $rep parent ffff: protocol ipv6 pref 1 \
flower \
dst_ip 1:1:1::3:1040:1009 \
src_ip 1:1:1::3:1040:1008 \
ip_proto tcp \
ip_tos 0x3 \
ip_ttl 63\
pedit ex \
munge ipv6 src set 2:2:2::3:1040:1009 \
munge ipv6 dst set 2:2:2::3:1040:1008 \
munge ipv6 hlimit dec \
action mirred egress redirect dev $NIC
IPv4 and IPv6 header rewrite is only supported with match on UDP/TCP/ICMP protocols.
TCP/UDP Source and Destination Ports
TCP/UDP source and destinations ports
Supported kernels: kernel > 4.16 & RHEL > 7.6
In OVS dump flows:
TCP:
set(tcp(src= 32768/0xffff,dst=32768/0xffff)),
UDP:
set(udp(src= 32768/0xffff,dst=32768/0xffff)),
Using TC rules:
TCP:
tc filter add dev $rep parent ffff: protocol ip pref 1 \
flower \
dst_ip 1.1.1.1 \
src_ip 1.1.1.2 \
ip_proto tcp \
ip_tos 0x3 \
ip_ttl 63 \
pedit ex \
pedit ex munge ip tcp sport set 200
pedit ex munge ip tcp dport set 200
action mirred egress redirect dev $NIC
UDP:
tc filter add dev $rep parent ffff: protocol ip pref 1 \
flower \
dst_ip 1.1.1.1 \
src_ip 1.1.1.2 \
ip_proto udp \
ip_tos 0x3 \
ip_ttl 63 \
pedit ex \
pedit ex munge ip udp sport set 200
pedit ex munge ip udp dport set 200
action mirred egress redirect dev $NIC
VLAN
ID
Supported on all kernels.
In OVS dump flows:
Set(vlan(vid=2347,pcp=0/0)),
Using TC rules:
tc filter add dev $rep parent ffff: protocol 802.1Q pref 1 \
flower \
vlan_ethtype 0x800 \
vlan_id 100 \
vlan_prio 0 \
action vlan modify id 11 pipe
action mirred egress redirect dev $NIC
Connection Tracking
The TC connection tracking action performs connection tracking lookup by sending the packet to netfilter conntrack module. Newly added connections may be associated, via the ct commit action, with a 32 bit mark, 128 bit label and source/destination NAT values.
The following example allows ingress tcp traffic from the uplink representor to vf1_rep, while assuring that egress traffic from vf1_rep is only allowed on established connections. In addition, mark and source IP NAT is applied.
In OVS dump flows:
ct(zone=2,nat)
ct_state(+est+trk)
actions:ct(commit,zone=2,mark=0x4/0xffffffff,nat(src=5.5.5.5))
Using TC rules:
# tc filter add dev $uplink_rep ingress chain 0 prio 1 proto ip \
flower \
ip_proto tcp \
ct_state -trk \
action ct zone 2 nat pipe
action goto chain 2
# tc filter add dev $uplink_rep ingress chain 2 prio 1 proto ip \
flower \
ct_state +trk+new \
action ct zone 2 commit mark 0xbb nat src addr 5.5.5.7 pipe \
action mirred egress redirect dev $vf1_rep
# tc filter add dev $uplink_rep ingress chain 2 prio 1 proto ip \
flower \
ct_zone 2 \
ct_mark 0xbb \
ct_state +trk+est \
action mirred egress redirect dev $vf1_rep
#Setup filters on $vf1_rep, allowing only established connections of zone 2 through, and reverse nat (dst nat in this case)
# tc filter add dev $vf1_rep ingress chain 0 prio 1 proto ip \
flower \
ip_proto tcp \
ct_state -trk \
action ct zone 2 nat pipe \
action goto chain 1
# tc filter add dev $vf1_rep ingress chain 1 prio 1 proto ip \
flower \
ct_zone 2 \
ct_mark 0xbb \
ct_state +trk+est \
action mirred egress redirect dev eth0
Connection Tracking Performance Tuning
Max offloaded connections—specifies the limit on the number of offloaded connections.
Example:# devlink dev param set pci/${pci_dev} name ct_max_offloaded_conns value $max cmode runtime
Allow mixed NAT/non-NAT CT—allows offloading of the following scenario:
• cookie=
0x0, duration=21.843s, table=0, n_packets=4838718, n_bytes=241958846, ct_state=-trk,ip,in_port=enp8s0f0 actions=ct(table=1,zone=2) • cookie=0x0, duration=21.823s, table=1, n_packets=15363, n_bytes=773526, ct_state=+new+trk,ip,in_port=enp8s0f0 actions=ct(commit,zone=2,nat(dst=11.11.11.11)),output:"enp8s0f0_1"• cookie=0x0, duration=21.806s, table=1, n_packets=4767594, n_bytes=238401190, ct_state=+est+trk,ip,in_port=enp8s0f0 actions=ct(zone=2,nat),output:"enp8s0f0_1"Example:
# echo enable > /sys/
class/net/<device>/compat/devlink/ct_action_on_nat_conns
Forward to Chain (TC Only)
TC interface supports adding flows on different chains. Only chain 0 is accessed by default. Access to the other chains requires usafe of the goto action.
In this example, a flow is created on chain 1 without any match and redirect to wire.
The second flow is created on chain 0 and match on source MAC and action goto chain 1.
This example simulates simple MAC spoofing.
#tc filter add dev $rep parent ffff: protocol all chain 1 pref 1 \
flower \
action mirred egress redirect dev $NIC
#tc filter add dev $rep parent ffff: protocol all chain 1 pref 1 \
flower \
src_mac aa:bb:cc:aa:bb:cc
action goto chain 1
Port Mirroring (Flow Based VF Traffic Mirroring for ASAP²)
Unlike para-virtual configurations, when the VM traffic is offloaded to the hardware via SR-IOV VF, the host side Admin cannot snoop the traffic (e.g. for monitoring).
ASAP² uses the existing mirroring support in OVS and TC along with the enhancement to the offloading logic in the driver to allow mirroring the VF traffic to another VF.
The mirrored VF can be used to run traffic analyzer (tcpdump, wireshark, etc) and observe the traffic of the VF being mirrored.
The example below shows the creation of port mirror on the following configuration:
# ovs-vsctl show
09d8a574-9c39-465c-9f16-47d81c12f88a
Bridge br-vxlan
Port "enp4s0f0_1"
Interface "enp4s0f0_1"
Port "vxlan0"
Interface "vxlan0"
type: vxlan
options: {key="100", remote_ip="192.168.1.14"}
Port "enp4s0f0_0"
Interface "enp4s0f0_0"
Port "enp4s0f0_2"
Interface "enp4s0f0_2"
Port br-vxlan
Interface br-vxlan
type: internal
ovs_version: "2.14.1"
To set enp4s0f0_0 as the mirror port, and mirror all of the traffic:
# ovs-vsctl -- --id=
@pget port enp4s0f0_0 \ -- --id=@mcreate mirror name=m0 select-all=trueoutput-port=@p\ -- set bridge br-vxlan mirrors=@mTo set enp4s0f0_0 as the mirror port, and only mirror the traffic, the destination is enp4s0f0_1:
# ovs-vsctl -- --id=
@p1get port enp4s0f0_0 \ -- --id=@p2get port enp4s0f0_1 \ -- --id=@mcreate mirror name=m0 select-dst-port=@p2output-port=@p1\ -- set bridge br-vxlan mirrors=@mTo set enp4s0f0_0 as the mirror port, and only mirror the traffic the source is enp4s0f0_1:
# ovs-vsctl -- --id=
@p1get port enp4s0f0_0 \ -- --id=@p2get port enp4s0f0_1 \ -- --id=@mcreate mirror name=m0 select-src-port=@p2output-port=@p1\ -- set bridge br-vxlan mirrors=@mTo set enp4s0f0_0 as the mirror port and mirror, all the traffic on enp4s0f0_1:
# ovs-vsctl -- --id=
@p1get port enp4s0f0_0 \ -- --id=@p2get port enp4s0f0_1 \ -- --id=@mcreate mirror name=m0 select-dst-port=@p2select-src-port=@p2output-port=@p1\ -- set bridge br-vxlan mirrors=@m
To clear the mirror port:
# ovs-vsctl clear bridge br-vxlan mirrors
Mirroring using TC:
Mirror to VF
tc filter add dev $rep parent ffff: protocol arp pref 1 \
flower \
dst_mac e4:1d:2d:5d:25:35 \
src_mac e4:1d:2d:5d:25:34 \
action mirred egress mirror dev $mirror_rep pipe \
action mirred egress redirect dev $NIC
Mirror to tunnel:
tc filter add dev $rep parent ffff: protocol arp pref 1 \
flower \
dst_mac e4:1d:2d:5d:25:35 \
src_mac e4:1d:2d:5d:25:34 \
action tunnel_key set \
src_ip 1.1.1.1 \
dst_ip 1.1.1.2 \
dst_port 4789 \
id 768 \
pipe \
action mirred egress mirror dev vxlan100 pipe \
action mirred egress redirect dev $NIC
Forward to Multiple Destinations
Forward to up 32 destinations (representors and tunnels) is supported using TC.
Example 1: forward to 32 VFs.
tc filter add dev $NIC parent ffff: protocol arp pref 1 \
flower \
dst_mac e4:1d:2d:5d:25:35 \
src_mac e4:1d:2d:5d:25:34 \
action mirred egress mirror dev $rep0 pipe \
action mirred egress mirror dev $rep1 pipe \
...
action mirred egress mirror dev $rep30 pipe \
action mirred egress redirect dev $rep31
Example 2: forward to 16 tunnels.
tc filter add dev $rep parent ffff: protocol arp pref 1 \
flower \
dst_mac e4:1d:2d:5d:25:35 \
src_mac e4:1d:2d:5d:25:34 \
action tunnel_key set src_ip $ip_src dst_ip $ip_dst \
dst_port 4789 id 0 nocsum \
pipe action mirred egress mirror dev vxlan0 pipe \
action tunnel_key set src_ip $ip_src dst_ip $ip_dst \
dst_port 4789 id 1 nocsum \
pipe action mirred egress mirror dev vxlan0 pipe \
...
action tunnel_key set src_ip $ip_src dst_ip $ip_dst \
dst_port 4789 id 15 nocsum \
pipe action mirred egress redirect dev vxlan0
TC supports up to 32 actions
If header rewrite is used, then all destinations should have the same header rewrite
If VLAN push/pop is used, then all destinations should have the same VLAN ID and actions
sFLOW
This feature allows for monitoring traffic sent between two VMs on the same host using an sFlow collector.
The example below shows the creation of port mirroring on the following configuration.
# ovs-vsctl show
09d8a574-9c39-465c-9f16-47d81c12f88a
Bridge br-vxlan
Port "enp4s0f0_1"
Interface "enp4s0f0_1"
Port "vxlan0"
Interface "vxlan0"
type: vxlan
options: {key="100", remote_ip="192.168.1.14"}
Port "enp4s0f0_0"
Interface "enp4s0f0_0"
Port "enp4s0f0_2"
Interface "enp4s0f0_2"
Port br-vxlan
Interface br-vxlan
type: internal
ovs_version: "2.14.1"
To sample all traffic over the OVS bridge:
# ovs-vsctl -- --id=@sflow create sflow agent=\"$SFLOW_AGENT\" \
target=\"$SFLOW_TARGET:$SFLOW_PORT\" header=$SFLOW_HEADER \
sampling=$SFLOW_SAMPLING polling=10 \
-- set bridge br-vxlan sflow=@sflow
|
Parameter |
Description |
|
SFLOW_AGENT |
Indicates that the sFlow agent should send traffic from SFLOW_AGENT’s IP address |
|
SFLOW_TARGET |
Remote IP address of the sFLOW collector |
|
SFLOW_PORT |
Size of packet header to sample (in bytes) |
|
SFLOW_SAMPLING |
Sample rate |
To clear the sFLOW configuration:
# ovs-vsctl clear bridge br-vxlan mirrors
sFLOW using TC:
Sample to VF
tc filter add dev $rep parent ffff: protocol arp pref 1 \
flower \
dst_mac e4:1d:2d:5d:25:35 \
src_mac e4:1d:2d:5d:25:34 \
action sample rate 10 group 5 trunc 96 \
action mirred egress redirect dev $NIC
Userspace application is needed in order to process to sampled packet from the kernel. Example: https://github.com/Mellanox/libpsample
Rate Limit
OVS-kernel supports offload of VF rate limit using OVS configuration and TC.
The example below sets a rate limit to the VF related to representor eth0 to 10Mbps.
OVS:
# ovs-vsctl set interface eth0 ingress_policing_rate=10000
tc:
# tc_filter add dev eth0 root prio 1 protocol ip matchall skip_sw action police rate 10mbit burst 20k
Kernel Requirements
This kernel config should be enabled in order to support switchdev offload.
CONFIG_NET_ACT_CSUM – needed for action csum
CONFIG_NET_ACT_PEDIT – needed for header rewrite
CONFIG_NET_ACT_MIRRED – needed for basic forward
CONFIG_NET_ACT_CT – needed for connection tracking (supported from kernel 5.6)
CONFIG_NET_ACT_VLAN - needed for action vlan push/pop
CONFIG_NET_ACT_GACT
CONFIG_NET_CLS_FLOWER
CONFIG_NET_CLS_ACT
CONFIG_NET_SWITCHDEV
CONFIG_NET_TC_SKB_EXT - needed for connection tracking (supported from kernel 5.6)
CONFIG_NET_ACT_CT - needed for connection tracking (supported from kernel 5.6)
CONFIG_NFT_FLOW_OFFLOAD
CONFIG_NET_ACT_TUNNEL_KEY
CONFIG_NF_FLOW_TABLE - needed for connection tracking (supported from kernel 5.6)
CONFIG_SKB_EXTENSIONS - needed for connection tracking (supported from kernel 5.6)
CONFIG_NET_CLS_MATCHALL
CONFIG_NET_ACT_POLICE
CONFIG_MLX5_ESWITCH
VF Metering
OVS-kernel supports offloading of VF metering (TX and RX) using sysfs. Metering of number of packets per second (PPS) and bytes per second (BPS) is supported.
The example bellow sets Rx meter on VF 0 with value 10Mbps BPS.
echo 10000000 > /sys/class/net/enp4s0f0/device/sriov/0/meters/rx/bps/rate
echo 65536 > /sys/class/net/enp4s0f0/device/sriov/0/meters/rx/bps/burst
The example bellow sets Tx meter on VF 0 with value 1000 PPS.
echo 1000 > /sys/class/net/enp4s0f0/device/sriov/0/meters/tx/pps/rate
echo 100 > /sys/class/net/enp4s0f0/device/sriov/0/meters/tx/pps/burst
Both rate and burst must not be zero and burst may need to be adjusted according to the requirements.
The following counters can be used to query the number dropped packet/bytes:
#cat /sys/class/net/enp8s0f0/device/sriov/0/meters/rx/pps/packets_dropped
#cat /sys/class/net/enp8s0f0/device/sriov/0/meters/rx/pps/bytes_dropped
#cat /sys/class/net/enp8s0f0/device/sriov/0/meters/rx/bps/packets_dropped
#cat /sys/class/net/enp8s0f0/device/sriov/0/meters/rx/bps/bytes_dropped
#cat /sys/class/net/enp8s0f0/device/sriov/0/meters/tx/pps/packets_dropped
#cat /sys/class/net/enp8s0f0/device/sriov/0/meters/tx/pps/bytes_dropped
#cat /sys/class/net/enp8s0f0/device/sriov/0/meters/tx/bps/packets_dropped
#cat /sys/class/net/enp8s0f0/device/sriov/0/meters/tx/bps/bytes_dropped
Representor Metering
Metering for uplink and VF representors traffic support has been added.
Traffic going to a representor device can be a result of a miss in the embedded switch (eSwitch) FDB tables. This means that a packet which arrived from that representor into the eSwitch was not matched against the existing rules in the hardware FDB tables and needs to be forwarded to software to be handled there and is, therefore, forwarded to the originating representor device driver.
The meter allows to configure the max rate [packets/sec] and max burst [packets] for traffic going to the representor driver. Any traffic exceeding values provided by the user will be dropped in hardware. There are statistics that show number of dropped packets.
The configuration of a representors metering is done via a new sysfs called miss_rl_cfg.
Full path of the miss_rl_cfg parameter: /sys/class/net//rep_config/miss_rl_cfg
Usage: echo ”<rate> <burst>” > /sys/class/net//rep_config/miss_rl_cfg. Rate is the max rate of packets allowed for this representor (in packets/sec units) and burst is the max burst size allowed for this representor (in packets units). Both values must be specified. The default is 0 for both, meaning unlimited rate and burst.
To view the amount of packets and bytes that were dropped due to traffic exceeding the user-provided rate and burst, two read-only sysfs for statistics are exposed.
/sys/class/net//rep_config/miss_rl_dropped_bytes counts how many FDB-miss bytes were dropped due to reaching the miss limits
/sys/class/net//rep_config/miss_rl_dropped_packets counts how many FDB-miss packets were dropped due to reaching the miss limits
Open vSwitch Metering
There are two types of meters, kpps (kilobits per second) and pktps(packets per second), which are described in Meter Syntax of OpenFlow 1.3+ Switch Meter Table Commands. OVS-Kernel supports offloading them both.
The example below is to offload a kpps meter. Please follow the steps after doing basic configurations as described in section 5.1.3.
Create OVS meter with a target rate.
ovs-ofctl -O OpenFlow13 add-meter ovs-sriov meter=
1,kbps,band=type=drop,rate=204800Delete the default rule.
ovs-ofctl del-flows ovs-sriov
Configure OpenFlow rules. Here VF bandwidth on the receiving side will be limited by the rate configured in step 1.
ovs-ofctl -O OpenFlow13 add-flow ovs-sriov
'ip,dl_dst=e4:11:22:33:44:50,actions= meter:1,output:enp4s0f0_0'ovs-ofctl -O OpenFlow13 add-flow ovs-sriov'ip,dl_src=e4:11:22:33:44:50,actions= output:enp4s0f0'ovs-ofctl -O OpenFlow13 add-flow ovs-sriov'arp,actions=normal'Run iperf server and be ready to receive UDP traffic. On the outer node, run iperf client to send UDP traffic to this VF. After traffic starts, check the offloaded meter rule.
ovs-appctl dpctl/dump-flows --names type=offloaded recirc_id(
0),in_port(enp4s0f0),eth(dst=e4:11:22:33:44:50),eth_type(0x0800),ipv4(frag=no), packets:11626587, bytes:17625889188, used:0.470s, actions:meter(0),enp4s0f0_0
In order to verify metering, iperf client should set the target bandwidth with a number which is larger than the meter rate configured. Then it will be visible that packets are received with the limited rate on the server side and the extra packets are dropped by hardware.
Multiport eSwitch Mode
The multiport eSwitch mode allows to add rules on a VF representor with an action forwarding the packet to the physical port of the physical function. This can be used to implement failover or forward packets based on external information such the cost of the route.
To configure this more, the nvconig parameter LAG_RESOURCE_ALLOCATION must be set.
After the driver loads, configure multiport eSwitch for each PF where enp8s0f0 and enp8s0f1 represent the netdevices for the PFs.
echo multiport_esw > /sys/
class/net/enp8s0f0/compat/devlink/lag_port_select_mode echo multiport_esw > /sys/class/net/enp8s0f1/compat/devlink/lag_port_select_modeThe mode becomes operational after entering switchdev mode on both PFs.
Rule example:
tc filter add dev enp8s0f0_0 prot ip root flower dst_ip 7.7.7.7 action mirred egress redirect dev enp8s0f1
OVS-DPDK Hardware Offloads
OVS-DPDK Hardware Offloads Configuration
To configure OVS-DPDK HW offloads:
Unbind the VFs.
echo
0000:04:00.2> /sys/bus/pci/drivers/mlx5_core/unbind echo0000:04:00.3> /sys/bus/pci/drivers/mlx5_core/unbindNote: VMs with attached VFs must be powered off to be able to unbind the VFs.
Change the e-switch mode from Legacy to SwitchDev on the PF device (make sure all VFs are unbound). This will also create the VF representor netdevices in the host OS.
echo switchdev > /sys/
class/net/enp4s0f0/compat/devlink/modeTo revert to SR-IOV Legacy mode:
echo legacy > /sys/
class/net/enp4s0f0/compat/devlink/modeNote that running this command will also result in the removal of the VF representor netdevices.
Bind the VFs.
echo
0000:04:00.2> /sys/bus/pci/drivers/mlx5_core/bind echo0000:04:00.3> /sys/bus/pci/drivers/mlx5_core/bindRun the Open vSwitch service.
systemctl start openvswitch
Enable hardware offload (disabled by default).
ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-init=
trueovs-vsctl set Open_vSwitch . other_config:hw-offload=trueConfigure the DPDK white list.
ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-extra=
"-a 0000:01:00.0,representor=[0],dv_flow_en=1,dv_esw_en=1,dv_xmeta_en=1"WarningRepresentor=[0-N]
Restart the Open vSwitch service. This step is required for HW offload changes to take effect.
systemctl restart openvswitch
Create OVS-DPDK bridge.
ovs-vsctl --no-wait add-br br0-ovs -- set bridge br0-ovs datapath_type=netdev
Add PF to OVS.
ovs-vsctl add-port br0-ovs pf -- set Interface pf type=dpdk options:dpdk-devargs=
0000:88:00.0Add representor to OVS.
ovs-vsctl add-port br0-ovs representor -- set Interface representor type=dpdk options:dpdk-devargs=
0000:88:00.0,representor=[0]WarningRepresentor=[0-N]
Offloading VXLAN Encapsulation/Decapsulation Actions
vSwitch in userspace rather than kernel-based Open vSwitch requires an additional bridge. The purpose of this bridge is to allow use of the kernel network stack for routing and ARP resolution.
The datapath needs to look-up the routing table and ARP table to prepare the tunnel header and transmit data to the output port.
Configuring VXLAN Encap/Decap Offloads
The configuration is done with:
PF on 0000:03:00.0 PCI and MAC 98:03:9b:cc:21:e8
Local IP 56.56.67.1 - br-phy interface will be configured to this IP
Remote IP 56.56.68.1
To configure OVS-DPDK VXLAN:
Create a br-phy bridge.
ovs-vsctl add-br br-phy -- set Bridge br-phy datapath_type=netdev -- br-set-external-id br-phy bridge-id br-phy -- set bridge br-phy fail-mode=standalone other_config:hwaddr=
98:03:9b:cc:21:e8Attach PF interface to br-phy bridge.
ovs-vsctl add-port br-phy p0 -- set Interface p0 type=dpdk options:dpdk-devargs=
0000:03:00.0Configure IP to the bridge.
ip addr add
56.56.67.1/24dev br-phyCreate a br-ovs bridge.
ovs-vsctl add-br br-ovs -- set Bridge br-ovs datapath_type=netdev -- br-set-external-id br-ovs bridge-id br-ovs -- set bridge br-ovs fail-mode=standalone
Attach representor to br-ovs.
ovs-vsctl add-port br-ovs pf0vf0 -- set Interface pf0vf0 type=dpdk options:dpdk-devargs=
0000:03:00.0,representor=[0]Add a port for the VXLAN tunnel.
ovs-vsctl add-port ovs-sriov vxlan0 -- set
interfacevxlan0 type=vxlan options:local_ip=56.56.67.1options:remote_ip=56.56.68.1options:key=45options:dst_port=4789
Connection Tracking Offload
Connection tracking enables stateful packet processing by keeping a record of currently open connections.
OVS flows using connection tracking can be accelerated using advanced Network Interface Cards (NICs) by offloading established connections.
To view offloaded connections, run:
ovs-appctl dpctl/offload-stats-show
SR-IOV VF LAG
To configure OVS-DPDK SR-IOV VF LAG:
Enable SR-IOV on the NICs.
mlxconfig -d <PCI> set SRIOV_EN=
1Allocate the desired number of VFs per port.
echo $n > /sys/
class/net/<net name>/device/sriov_numvfsUnbind all VFs.
echo <VF PCI> >/sys/bus/pci/drivers/mlx5_core/unbind
Change both NICs' mode to SwitchDev.
devlink dev eswitch set pci/<PCI> mode switchdev
Create Linux bonding using kernel modules.
modprobe bonding mode=<desired mode>
Note: Other bonding parameters can be added here. The supported Bond modes are: Active-Backup, XOR and LACP.
Bring all PFs and VFs down.
ip link set <PF/VF> down
Attach both PFs to the bond.
ip link set <PF> master bond0
To work with VF-LAG with OVS-DPDK, add the bond master (PF) to the bridge.
ovs-vsctl add-port br-phy p0 -- set Interface p0 type=dpdk options:dpdk-devargs=
0000:03:00.0options:dpdk-lsc-interrupt=trueAdd representor $N of PF0 or PF1 to a bridge.
ovs-vsctl add-port br-phy rep$N -- set Interface rep$N type=dpdk options:dpdk-devargs=<PF0 PCI>,representor=pf0vf$N OR ovs-vsctl add-port br-phy rep$N -- set Interface rep$N type=dpdk options:dpdk-devargs=<PF0 PCI>,representor=pf1vf$N
VirtIO Acceleration through VF Relay (Software & Hardware vDPA)
Hardware vDPA is supported on ConnectX-6 Dx, ConnectX-6 Lx & BlueField-2 cards and above only.
Hardware vDPA is enabled by default. In case your hardware does not support vDPA, the driver will fall back to Software vDPA.
To check which vDPA mode is activated on your driver, run: ovs-ofctl -O OpenFlow14 dump-ports br0-ovs and look for hw-mode flag.
This feature has not been accepted to the OVS-DPDK Upstream yet, making its API subject to change.
In user space, there are two main approaches for communicating with a guest (VM), either through SR-IOV, or through virtIO.
Phy ports (SR-IOV) allow working with port representor, which is attached to the OVS and a matching VF is given with pass-through to the guest. HW rules can process packets from up-link and direct them to the VF without going through SW (OVS). Therefore, using SR-IOV achieves the best performance.
However, SR-IOV architecture requires the guest to use a driver specific to the underlying HW. Specific HW driver has two main drawbacks:
Breaks virtualization in some sense (guest is aware of the HW). It can also limit the type of images supported.
Gives less natural support for live migration.
Using virtIO port solves both problems. However, it reduces performance and causes loss of some functionalities, such as, for some HW offloads, working directly with virtIO. To solve this conflict, a new netdev type- dpdkvdpa has been created. The new netdev is similar to the regular DPDK netdev, yet introduces several additional functionalities.
dpdkvdpa translates between phy port to virtIO port. It takes packets from the Rx queue and sends them to the suitable Tx queue, and allows transfer of packets from virtIO guest (VM) to a VF, and vice-versa, benefitting from both SR-IOV and virtIO.
To add vDPA port:
ovs-vsctl add-port br0 vdpa0 -- set Interface vdpa0 type=dpdkvdpa \
options:vdpa-socket-path=<sock path> \
options:vdpa-accelerator-devargs=<vf pci id> \
options:dpdk-devargs=<pf pci id>,representor=[id] \
options: vdpa-max-queues =<num queues> \
options: vdpa-sw=<true/false>
Note: vdpa-max-queues is an optional field. When the user wants to configure 32 vDPA ports, the maximum queues number is limited to 8.
vDPA Configuration in OVS-DPDK Mode
Prior to configuring vDPA in OVS-DPDK mode, follow the steps below.
Generate the VF.
echo
0> /sys/class/net/enp175s0f0/device/sriov_numvfs echo4> /sys/class/net/enp175s0f0/device/sriov_numvfsUnbind each VF.
echo <pci> > /sys/bus/pci/drivers/mlx5_core/unbind
Switch to SwitchDev mode.
echo switchdev >> /sys/
class/net/enp175s0f0/compat/devlink/modeBind each VF.
echo <pci> > /sys/bus/pci/drivers/mlx5_core/bind
Initialize OVS with:
ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-init=
trueovs-vsctl --no-wait set Open_vSwitch . other_config:hw-offload=true
To configure vDPA in OVS-DPDK mode on ConnectX-5 cards and above:
Open vSwitch configuration.
ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-extra=
"-a 0000:01:00.0,representor=[0],dv_flow_en=1,dv_esw_en=1,dv_xmeta_en=1"/usr/share/openvswitch/scripts/ovs-ctl restartCreate OVS-DPDK bridge.
ovs-vsctl add-br br0-ovs -- set bridge br0-ovs datapath_type=netdev ovs-vsctl add-port br0-ovs pf -- set Interface pf type=dpdk options:dpdk-devargs=
0000:01:00.0Create vDPA port as part of the OVS-DPDK bridge.
ovs-vsctl add-port br0-ovs vdpa0 -- set Interface vdpa0 type=dpdkvdpa options:vdpa-socket-path=/var/run/virtio-forwarder/sock0 options:vdpa-accelerator-devargs=
0000:01:00.2options:dpdk-devargs=0000:01:00.0,representor=[0] options: vdpa-max-queues=8
To configure vDPA in OVS-DPDK mode on BlueField cards:
Set the bridge with the software or hardware vDPA port:
On the ARM side:
Create the OVS-DPDK bridge.
ovs-vsctl add-br br0-ovs -- set bridge br0-ovs datapath_type=netdev ovs-vsctl add-port br0-ovs pf -- set Interface pf type=dpdk options:dpdk-devargs=
0000:af:00.0ovs-vsctl add-port br0-ovs rep-- set Interface rep type=dpdk options:dpdk-devargs=0000:af:00.0,representor=[0]On the host side:
Create the OVS-DPDK bridge.
ovs-vsctl add-br br1-ovs -- set bridge br1-ovs datapath_type=netdev protocols=OpenFlow14 ovs-vsctl add-port br0-ovs vdpa0 -- set Interface vdpa0 type=dpdkvdpa options:vdpa-socket-path=/var/run/virtio-forwarder/sock0 options:vdpa-accelerator-devargs=
0000:af:00.2Note: To configure SW vDPA, add "options:vdpa-sw=true" to the end of the command.
Software vDPA Configuration in OVS-Kernel Mode
SW vDPA can also be used in configurations where the HW offload is done through TC and not DPDK.
Open vSwitch configuration.
ovs-vsctl set Open_vSwitch . other_config:dpdk-extra=
"-a 0000:01:00.0,representor=[0],dv_flow_en=1,dv_esw_en=0,idv_xmeta_en=0,isolated_mode=1"/usr/share/openvswitch/scripts/ovs-ctl restartCreate OVS-DPDK bridge.
ovs-vsctl add-br br0-ovs -- set bridge br0-ovs datapath_type=netdev
Create vDPA port as part of the OVS-DPDK bridge.
ovs-vsctl add-port br0-ovs vdpa0 -- set Interface vdpa0 type=dpdkvdpa options:vdpa-socket-path=/var/run/virtio-forwarder/sock0 options:vdpa-accelerator-devargs=
0000:01:00.2options:dpdk-devargs=0000:01:00.0,representor=[0] options: vdpa-max-queues=8Create Kernel bridge.
ovs-vsctl add-br br-kernel
Add representors to Kernel bridge.
ovs-vsctl add-port br-kernel enp1s0f0_0 ovs-vsctl add-port br-kernel enp1s0f0
Large MTU/Jumbo Frame Configuration
To configure MTU/jumbo frames:
Verify that the Kernel version on the VM is 4.14 or above.
cat /etc/redhat-release
Set the MTU on both physical interfaces in the host.
ifconfig ens4f0 mtu
9216Send a large size packet and verify that it is sent and received correctly.
tcpdump -i ens4f0 -nev icmp & ping
11.100.126.1-s9188-Mdo-c1Enable host_mtu in xml, and add the following values to xml.
host_mtu=
9216,csum=on,guest_csum=on,host_tso4=on,host_tso6=onExample:
<qemu:commandline> <qemu:arg value=
'-chardev'/> <qemu:arg value='socket,id=charnet1,path=/tmp/sock0,server'/> <qemu:arg value='-netdev'/> <qemu:arg value='vhost-user,chardev=charnet1,queues=16,id=hostnet1'/> <qemu:arg value='-device'/> <qemu:arg value='virtio-net-pci,mq=on,vectors=34,netdev=hostnet1,id=net1,mac=00:21:21:24:02:01,bus=pci.0,addr=0xC,page-per-vq=on,rx_queue_size=1024,tx_queue_size=1024,host_mtu=9216,csum=on,guest_csum=on,host_tso4=on,host_tso6=on'/> </qemu:commandline>Add mtu_request=9216 option to the OvS ports inside the container and restart the OVS:
ovs-vsctl add-port br0-ovs pf -- set Interface pf type=dpdk options:dpdk-devargs=
0000:c4:00.0mtu_request=9216OR:
ovs-vsctl add-port br0-ovs vdpa0 -- set Interface vdpa0 type=dpdkvdpa options:vdpa-socket-path=/tmp/sock0 options:vdpa-accelerator-devargs=
0000:c4:00.2options:dpdk-devargs=0000:c4:00.0,representor=[0] mtu_request=9216/usr/share/openvswitch/scripts/ovs-ctl restartStart the VM and configure the MTU on the VM.
ifconfig eth0
11.100.124.2/16up ifconfig eth0 mtu9216ping11.100.126.1-s9188-Mdo-c1
E2E Cache
This feature is at beta level.
OVS offload rules are based on a multi-table architecture. E2E cache feature enables merging the multi-table flow matches and actions into one joint flow.
This improves connection tracking performance by using a single-table when exact match is detected.
To s
et the E2E cache size (default = 4k):
ovs-vsctl set open_vswitch . other_config:e2e-size=<size>
systemctl restart openvswitch
Note: Make sure to restart the openvswitch service in order for the configuration to take effect.
To e
nable/disable E2E cache (default = disabled) :
ovs-vsctl set open_vswitch . other_config:e2e-enable=<true/false>
systemctl restart openvswitch
Note: Make sure to restart the openvswitch service in order for the configuration to take effect.
To run
E2E cache statistics:
ovs-appctl dpctl/dump-e2e-stats
To run E2E cache flows:
ovs-appctl dpctl/dump-e2e-flows
Geneve Encapsulation/Decapsulation
Geneve tunneling offload feature support includes matching on extension header.
To configure OVS-DPDK Geneve encap/decap:
Create a br-phy bridge.
ovs-vsctl --may-exist add-br br-phy -- set Bridge br-phy datapath_type=netdev -- br-set-external-id br-phy bridge-id br-phy -- set bridge br-phy fail-mode=standalone
Attach PF interface to br-phy bridge.
ovs-vsctl add-port br-phy pf -- set Interface pf type=dpdk options:dpdk-devargs=<PF PCI>
Configure IP to the bridge.
ifconfig br-phy <$local_ip_1> up
Create a br-int bridge.
ovs-vsctl --may-exist add-br br-
int-- set Bridge br-intdatapath_type=netdev -- br-set-external-id br-intbridge-id br-int-- set bridge br-intfail-mode=standaloneAttach representor to br-int.
ovs-vsctl add-port br-
intrep$x -- set Interface rep$x type=dpdk options:dpdk-devargs=<PF PCI>,representor=[$x]Add a port for the GENEVE tunnel.
ovs-vsctl add-port br-
intgeneve0 -- setinterfacegeneve0 type=geneve options:key=<VNI> options:remote_ip=<$remote_ip_1> options:local_ip=<$local_ip_1>
Parallel Offloads
OVS-DPDK supports parallel insertion and deletion of offloads (flow & CT). While multiple threads are supported, by default only one is used.
To c
onfigure multiple threads:
ovs-vsctl set Open_vSwitch . other_config:n-offload-threads=3
Make sure to restart the openvswitch service in order for the configuration to take effect.
systemctl restart openvswitch
For more information, see the OvS user manual.
sFlow
This feature allows for monitoring traffic sent between two VMs on the same host using an sFlow collector.
To sample all traffic over the OVS bridge, run the following:
# ovs-vsctl -- --id=@sflow create sflow agent=\"$SFLOW_AGENT\" \
target=\"$SFLOW_TARGET:$SFLOW_PORT\" header=$SFLOW_HEADER \
sampling=$SFLOW_SAMPLING polling=10 \
-- set bridge sflow=@sflow
|
Parameter |
Description |
|
SFLOW_AGENT |
Indicates that the sFlow agent should send traffic from SFLOW_AGENT’s IP address |
|
SFLOW_TARGET |
Remote IP address of the sFLOW collector |
|
SFLOW_PORT |
Remote IP destination port of the sFlow collector |
|
SFLOW_HEADER |
Size of packet header to sample (in bytes) |
|
SFLOW_SAMPLING |
Sample rate |
To clear the sFLOW configuration, runt he following:
# ovs-vsctl clear bridge br-vxlan mirrors
Currently sFlow for OVS-DPDK is supported without CT.
CT CT NAT
To enable ct-ct-nat offloads in OvS-DPDK, execute the following command (deafult value is false):
ovs-vsctl set open_vswitch . other_config:ct-action-on-nat-conns=true
If disabled, ct-ct-nat configurations will not be fully offloaded, improving connection offloading rate for
other cases (ct and ct-nat).
If enabled, ct-ct-nat configurations will be fully offloaded but ct and ct-nat offloading
will be slower to be created.
OpenFlow Meters (OpenFlow13+):
OpenFlow meters in OVS are implemented according to RFC 2697 (Single Rate Three Color Marker—srTCM).
The srTCM meters an IP packet stream and marks its packets either green, yellow, or red. The color is decided on a Committed Information Rate (CIR) and two associated burst sizes, Committed Burst Size (CBS), and Excess Burst Size (EBS).
A packet is marked green if it does not exceed the CBS, yellow if it exceeds the CBS but not the EBS, and red otherwise.
The volume of green packets should never be smaller than the CIR.
To configure a meter in OVS:
Create a meter over a certain bridge:
-
ovs-ofctl -O openflow13 add-meter $bridge meter=$id,$pktps/$kbps,band=type=drop,rate=$rate,[burst,burst_size=$burst_size]
Parameters:
Parameter
Description
bridge
Name of the bridge on which the meter will be applied.
id
Unique meter ID (32 bits) which will be used as an identifier for the meter.
pktps/kbps
Indication if the meter should work according to packets-per-second or kilobits-per-second.
rate
Rate of pktps/kbps of allowed data transmission.
burst
If set, enables burst support for meter bands through the “burst_size” parameter.
burst_size
If burst is specified for the meter entry, configures the maximum burst allowed for the band in kilobits/packets, depending on whether kbps or pktps was specified. If unspecified, the switch is free to select some reasonable value depending on its configuration. Currently, if burst was not specified, the burst_size parameter is set as the “rate”.
-
Add the meter to a certain OpenFlow rule. For example:
ovs-ofctl -O openflow13 add-flow $bridge "table=
0,actions=meter:$id,normal“View the meter statistics:
ovs-ofctl -O openflow13 meter-stats $bridge meter=$id
For more information, refer to openvswitch documentation http://www.openvswitch.org/support/dist-docs/ovs-ofctl.8.txt
Hardware vDPA Installation
Hardware vDPA requires QEMU v2.12 (or with upstream 6.1.0) and DPDK v20.11 as minimal versions.
To install QEMU:
Clone the sources:
git clone https://git.qemu.org/git/qemu.git cd qemu git checkout v2.12
Build QEMU:
mkdir bin cd bin ../configure --target-list=x86_64-softmmu --enable-kvm make -j24
To install DPDK:
Clone the sources:
git clone git://dpdk.org/dpdk cd dpdk git checkout v20.11
Install dependencies (if needed):
yum install cmake gcc libnl3-devel libudev-devel make pkgconfig valgrind-devel pandoc libibverbs libmlx5 libmnl-devel -y
Configure DPDK:
export RTE_SDK=$PWD make config T=x86_64-
native-linuxapp-gcc cd build sed -i's/\(CONFIG_RTE_LIBRTE_MLX5_PMD=\)n/\1y/g'.config sed -i's/\(CONFIG_RTE_LIBRTE_MLX5_VDPA_PMD=\)n/\1y/g'.configBuild DPDK:
make -j
Build the vDPA application:
cd $RTE_SDK/examples/vdpa/ make -j
Hardware vDPA Configuration
To configure huge pages:
mkdir -p /hugepages
mount -t hugetlbfs hugetlbfs /hugepages
echo <more> > /sys/devices/system/node/node0/hugepages/hugepages-1048576kB/nr_hugepages
echo <more> > /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages
To configure a vDPA VirtIO interface in an existing VM's xml file (using libvirt):
Open the VM's configuration xml for editing:
virsh edit <domain name>
Modify/add the following:
Change the top line to:
<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
Assign a memory amount and use 1GB page size for hugepages (size must be the same as used for the vDPA application), so that the memory configuration looks like the following.
<memory unit=
'KiB'>4194304</memory> <currentMemory unit='KiB'>4194304</currentMemory> <memoryBacking> <hugepages> <page size='1048576'unit='KiB'/> </hugepages> </memoryBacking>Assign an amount of CPUs for the VM CPU configuration, so that the vcpu and cputune configuration looks like the following.
<vcpu placement=
'static'>5</vcpu> <cputune> <vcpupin vcpu='0'cpuset='14'/> <vcpupin vcpu='1'cpuset='16'/> <vcpupin vcpu='2'cpuset='18'/> <vcpupin vcpu='3'cpuset='20'/> <vcpupin vcpu='4'cpuset='22'/> </cputune>Set the memory access for the CPUs to be shared, so that the cpu configuration looks like the following.
<cpu mode=
'custom'match='exact'check='partial'> <model fallback='allow'>Skylake-Server-IBRS</model> <numa> <cell id='0'cpus='0-4'memory='8388608'unit='KiB'memAccess='shared'/> </numa> </cpu>Set the emulator in use to be the one built in step "2. Build QEMU" above, so that the emulator configuration looks as follows.
<emulator><path to qemu executable></emulator>
Add a virtio interface using qemu command line argument entries, so that the new interface snippet looks as follows.
<qemu:commandline> <qemu:arg value=
'-chardev'/> <qemu:arg value='socket,id=charnet1,path=/tmp/sock-virtio0'/> <qemu:arg value='-netdev'/> <qemu:arg value='vhost-user,chardev=charnet1,queues=16,id=hostnet1'/> <qemu:arg value='-device'/> <qemu:arg value='virtio-net-pci,mq=on,vectors=6,netdev=hostnet1,id=net1,mac=e4:11:c6:d3:45:f2,bus=pci.0,addr=0x6, page-per-vq=on,rx_queue_size=1024,tx_queue_size=1024'/> </qemu:commandline>Note: In this snippet, the vhostuser socket file path, the amount of queues, the MAC and the PCI slot of the VirtIO device can be configured.
Running Hardware vDPA
Hardware vDPA supports SwitchDev mode only.
Create the ASAP2 environment:
Create the VFs.
Enter switchdev mode.
Set up OVS.
the vDPA application.
cd $RTE_SDK/examples/vdpa/build
./vdpa -w <VF PCI BDF>,class=vdpa --log-level=pmd,info -- -i
Create a vDPA port via the vDPA application CLI.
create /tmp/sock-virtio0 <PCI DEVICE BDF>
Note: The vhostuser socket file path must be the one used when configuring the VM.
Start the VM.
virsh start <domain name>
For further information on the vDPA application, please visit: https://doc.dpdk.org/guides/sample_app_ug/vdpa.html.
Bridge offload is supported on ConnectX-6 Dx NIC.
Bridge offload is supported SwitchDev mode only.
A Linux bridge is in-kernel software network switch (based on and implements subset of IEEE 802.1D standard) that is used to connect Ethernet segments together in a protocol-independent way. Packets are forwarded based on L2 Ethernet header addresses.
mlx5 provides capabilities to offload bridge data-plane unicast packet forwarding and VLAN management to hardware.
Basic Configuration
Initialize the ASAP2 environment:
Create the VFs.
Enter switchdev mode.
Create a bridge and add mlx5 representors to bridge:
ip link add name bridge0 type bridge ip link set enp8s0f0_0 master bridge0
Configuring VLAN
Enable VLAN filtering on the bridge.
ip link set bridge0 type bridge vlan_filtering
1Configure port VLAN matching (trunk mode). In this configuration, only packets with specified VID are allowed.
bridge vlan add dev enp8s0f0_0 vid
2Configure port VLAN tagging (access mode). In this configuration VLAN header in pushed/popped on reception/transmission on port.
bridge vlan add dev enp8s0f0_0 vid
2pvid untagged
VF LAG Support
Bridge supports offloading on bond net device that is fully initialized with mlx5 uplink representors and is in single (shared) FDB LAG mode. Details about initialization of LAG are provided in SR-IOV VF LAG section, above.
Add bonding net device to bridge.
ip link set bond0 master bridge0
For further information on interacting with Linux bridge via iproute2 bridge tool, please consult man page (man 8 bridge).
Download and install the MFT package corresponding to your computer’s operating system. You would need the kernel-devel or kernel-headers RPM before the tools are built and installed.
The package is available at nvidia.com/en-us/networking/ → Products → Software → Firmware Tools.
Start the mst driver.
# mst start Starting MST (Mellanox Software Tools) driver set Loading MST PCI module - Success Loading MST PCI configuration module - Success Create devices
Show the devices status.
ST modules: ------------ MST PCI module loaded MST PCI configuration module loaded PCI devices: ------------ DEVICE_TYPE MST PCI RDMA NET NUMA ConnectX4lx(rev:
0) /dev/mst/mt4117_pciconf0.104:00.1net-enp4s0f1 NA ConnectX4lx(rev:0) /dev/mst/mt4117_pciconf004:00.0net-enp4s0f0 NA # mlxconfig -d /dev/mst/mt4117_pciconf0 q | head -16Device #1: ---------- Device type: ConnectX4lx PCI device: /dev/mst/mt4117_pciconf0 Configurations: Current SRIOV_EN True(1) NUM_OF_VFS8PF_LOG_BAR_SIZE5VF_LOG_BAR_SIZE5NUM_PF_MSIX63NUM_VF_MSIX11LINK_TYPE_P1 ETH(2) LINK_TYPE_P2 ETH(2)Make sure your configuration is as follows:
* SR-IOV is enabled (SRIOV_EN=1)
* The number of enabled VFs is enough for your environment (NUM_OF_VFS=N)
* The port’s link type is Ethernet (LINK_TYPE_P1/2=2) when applicable
If this is not the case, use mlxconfig to enable that, as follows:Enable SR-IOV.
# mlxconfig -d /dev/mst/mt4115_pciconf0 s SRIOV_EN=
1Set the number of required VFs.
# mlxconfig -d /dev/mst/mt4115_pciconf0 s NUM_OF_VFS=
8Set the link type to Ethernet.
# mlxconfig -d /dev/mst/mt4115_pciconf0 s LINK_TYPE_P1=
2# mlxconfig -d /dev/mst/mt4115_pciconf0 s LINK_TYPE_P2=2
Reset the firmware.
# mlxfwreset -d /dev/mst/mt4115_pciconf0 reset
Query the firmware to make sure everything is set correctly.
# mlxconfig -d /dev/mst/mt4115_pciconf0 q