Add HFI VNIC design document explaining the VNIC architecture and the driver design. Reviewed-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx> Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@xxxxxxxxx> --- Documentation/infiniband/hfi_vnic.txt | 102 ++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 Documentation/infiniband/hfi_vnic.txt diff --git a/Documentation/infiniband/hfi_vnic.txt b/Documentation/infiniband/hfi_vnic.txt new file mode 100644 index 0000000..c6c801e --- /dev/null +++ b/Documentation/infiniband/hfi_vnic.txt @@ -0,0 +1,102 @@ +Intel Omni-Path Host Fabric Interface (HFI) Virtual Network Interface +Controller (VNIC) feature supports Ethernet functionality over Omni-Path +fabric by encapsulating the Ethernet packets between HFI nodes. + +The patterns of exchanges of Omni-Path encapsulated Ethernet packets +involves one or more virtual Ethernet switches overlaid on the Omni-Path +fabric topology. A subset of HFI nodes on the Omni-Path fabric are +permitted to exchange encapsulated Ethernet packets across a particular +virtual Ethernet switch. The virtual Ethernet switches are logical +abstractions achieved by configuring the HFI nodes on the fabric for +header generation and processing. In the simplest configuration all HFI +nodes across the fabric exchange encapsulated Ethernet packets over a +single virtual Ethernet switch. A virtual Ethernet switch, is effectively +an independent Ethernet network. The configuration is performed by an +Ethernet Manager (EM) which is part of the trusted Fabric Manager (FM) +application. HFI nodes can have multiple VNICs each connected to a +different virtual Ethernet switch. The below diagram presents a case +of two virtual Ethernet switches with two HFI nodes. + + +-------------------+ + | Subnet/ | + | Ethernet | + | Manager | + +-------------------+ + / / + / / + / / + / / ++-----------------------------+ +------------------------------+ +| Virtual Ethernet Switch | | Virtual Ethernet Switch | +| +---------+ +---------+ | | +---------+ +---------+ | +| | VPORT | | VPORT | | | | VPORT | | VPORT | | ++--+---------+----+---------+-+ +-+---------+----+---------+---+ + | \ / | + | \ / | + | \/ | + | / \ | + | / \ | + +-----------+------------+ +-----------+------------+ + | VNIC | VNIC | | VNIC | VNIC | + +-----------+------------+ +-----------+------------+ + | HFI | | HFI | + +------------------------+ +------------------------+ + + +Intel HFI VNIC software design is presented in the below diagram. +HFI VNIC functionality has a HW dependent component and a HW +independent component. + +The support has been added for IB device to allocate and free the RDMA +netdev devices. The RDMA netdev supports interfacing with the network +stack thus creating standard network interfaces. HFI_VNIC is an RDMA +netdev device type. + +The HW dependent VNIC functionality is part of the HFI1 driver. It +implements the verbs to allocate and free the HFI_VNIC RDMA netdev. +It involves HW resource allocation/management for VNIC functionality. +It interfaces with the network stack and implements the required +net_device_ops functions. It expects Omni-Path encapsulated Ethernet +packets in the transmit path and provides HW access to them. It strips +the Omni-Path header from the received packets before passing them up +the network stack. It also implements the RDMA netdev control operations. + +The HFI VNIC module implements the HW independent VNIC functionality. +It consists of two parts. The VNIC Ethernet Management Agent (VEMA) +registers itself with IB core as an IB client and interfaces with the +IB MAD stack. It exchanges the management information with the Ethernet +Manager (EM) and the VNIC netdev. The VNIC netdev part allocates and frees +the HFI_VNIC RDMA netdev devices. It overrides the net_device_ops functions +set by HW dependent VNIC driver where required to accommodate any control +operation. It also handles the encapsulation of Ethernet packets with an +Omni-Path header in the transmit path. For each VNIC interface, the +information required for encapsulation is configured by the EM via VEMA MAD +interface. It also passes any control information to the HW dependent driver +by invoking the RDMA netdev control operations. + + +-------------------+ +----------------------+ + | | | Linux | + | IB MAD | | Network | + | | | Stack | + +-------------------+ +----------------------+ + | | | + | | | + +----------------------------+ | + | | | + | HFI VNIC Module | | + | (HFI VNIC RDMA Netdev | | + | & EMA functions) | | + | | | + +----------------------------+ | + | | + | | + +------------------+ | + | IB core | | + +------------------+ | + | | + | | + +--------------------------------------------+ + | | + | HFI1 Driver with VNIC support | + | | + +--------------------------------------------+ -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
