.. SPDX-License-Identifier: GPL-2.0
=================
PCI vNTB Function
=================
:Author: Frank Li <[email protected]>
The difference between PCI NTB function and PCI vNTB function is
PCI NTB function need at two endpoint instances and connect HOST1
and HOST2.
PCI vNTB function only use one host and one endpoint(EP), use NTB
connect EP and PCI host
.. code-block:: text
+------------+ +---------------------------------------+
| | | |
+------------+ | +--------------+
| NTB | | | NTB |
| NetDev | | | NetDev |
+------------+ | +--------------+
| NTB | | | NTB |
| Transfer | | | Transfer |
+------------+ | +--------------+
| | | | |
| PCI NTB | | | |
| EPF | | | |
| Driver | | | PCI Virtual |
| | +---------------+ | NTB Driver |
| | | PCI EP NTB |<------>| |
| | | FN Driver | | |
+------------+ +---------------+ +--------------+
| | | | | |
| PCI BUS | <-----> | PCI EP BUS | | Virtual PCI |
| | PCI | | | BUS |
+------------+ +---------------+--------+--------------+
PCI RC PCI EP
Constructs used for Implementing vNTB
=====================================
1) Config Region
2) Self Scratchpad Registers
3) Peer Scratchpad Registers
4) Doorbell (DB) Registers
5) Memory Window (MW)
Config Region:
--------------
It is same as PCI NTB Function driver
Scratchpad Registers:
---------------------
It is appended after Config region.
.. code-block:: text
+--------------------------------------------------+ Base
| |
| |
| |
| Common Config Register |
| |
| |
| |
+-----------------------+--------------------------+ Base + span_offset
| | |
| Peer Span Space | Span Space |
| | |
| | |
+-----------------------+--------------------------+ Base + span_offset
| | | + span_count * 4
| | |
| Span Space | Peer Span Space |
| | |
+-----------------------+--------------------------+
Virtual PCI Pcie Endpoint
NTB Driver NTB Driver
Doorbell Registers:
-------------------
Doorbell Registers are used by the hosts to interrupt each other.
Memory Window:
--------------
Actual transfer of data between the two hosts will happen using the
memory window.
Modeling Constructs:
====================
32-bit BARs.
====== ===============
BAR NO CONSTRUCTS USED
====== ===============
BAR0 Config Region
BAR1 Doorbell
BAR2 Memory Window 1
BAR3 Memory Window 2
BAR4 Memory Window 3
BAR5 Memory Window 4
====== ===============
64-bit BARs.
====== ===============================
BAR NO CONSTRUCTS USED
====== ===============================
BAR0 Config Region + Scratchpad
BAR1
BAR2 Doorbell
BAR3
BAR4 Memory Window 1
BAR5
====== ===============================
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