[RFC 01/10] IB/hfi-vnic: Virtual Network Interface Controller (VNIC) documentation

Vishwanathapura, Niranjana
2016-11-18T22:42:09Z

Add HFI VNIC design document explaining the VNIC architecture and the
driver design.

Change-Id: I7baa39444579dc582fe1e49b86e9cfc71f0a41a4
Reviewed-by: Dennis Dalessandro <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
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