Add HFI VNIC design document explaining the VNIC architecture and the driver design.
Change-Id: I7baa39444579dc582fe1e49b86e9cfc71f0a41a4 Reviewed-by: Dennis Dalessandro <dennis.dalessan...@intel.com> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathap...@intel.com> --- Documentation/infiniband/hfi_vnic.txt | 97 +++++++++++++++++++++++++++++++++++ 1 file changed, 97 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..3501288 --- /dev/null +++ b/Documentation/infiniband/hfi_vnic.txt @@ -0,0 +1,97 @@ +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. HFI VNIC Bus module decouples these two +functionalities. + +The HW dependent VNIC functionality is part of the HFI1 driver. It +implements the bus operations to do various tasks including HW resource +allocation for VNIC functionality and actual transmission and reception +of encapsulated Ethernet packets over the fabric. It creates a control +device (per HFI) on the HFI VNIC bus for the control plane operations +and VNIC devices for the data plane. Each VNIC device on the HFI VNIC +bus is addressed by the HFI instance, HFI port, and a VNIC port number +on the HFI port. + +The HFI VNIC module implements the HW independent VNIC functionality. +It consists of two drivers. The VNIC Ethernet Management Agent (VEMA) +driver binds with the control device on the VNIC bus and interfaces with +the Infiniband MAD stack. It exchanges the management information with +the Ethernet Manager (EM). The VNIC netdev driver binds with the VNIC +devices on the HFI VNIC bus and interfaces with the Linux network stack, +thus providing standard Ethernet network interfaces. The VNIC netdev +driver encapsulates the Ethernet packets with an Omni-Path header before +passing them to the HFI1 driver for transmission. Similarly, it +de-encapsulates the received Omni-Path packets before passing them to the +network stack. For each VNIC interface, the information required for +encapsulation is configured by EM via VEMA MAD interface. + + + +-------------------+ +----------------------+ + | | | Linux | + | IB MAD | | Network | + | | | Stack | + +-------------------+ +----------------------+ + | | + | | + +--------------------------------------------+ + | | + | HFI VNIC Module | + | (HFI VNIC Netdev and EMA drivers) | + | | + +--------------------------------------------+ + | + | + +--------------------------------------------+ + | HFI VNIC Bus | + +--------------------------------------------+ + | + | + +--------------------------------------------+ + | | + | HFI1 Driver with VNIC support | + | | + +--------------------------------------------+ -- 1.8.3.1