[PATCH v5 2/7] transport-fabrics: introduce Virtio-oF Qualified Name

[zhenwei pi <pizhenwei@bytedance.com>]

Add VQN section. The VQN is a little different from iSCSI/NVMe-oF on
style limitation. Because iSCSI/NVMe-of is storage specific protocol,
the full string IQN(for iSCSI/iSER) and NQN(for NVMe-oF) represents
a "storage access address". However, Virtio Over Fabrics works as
transport layer rather than device layer, a URL style string is better
to Virtio Over Fabrics. For example:
virtio-rdma://192.168.1.100:8549/blk-device/nvme-pool/849a39ad-8d7b-4a7a-adb6-e7407ace532c
virtio-tcpip://192.168.1.110/blk-device/hdd-pool/238151a7-acd7-4621-bbdf-382ddbccb6a1
virtio-tcpip://192.168.1.100:8549/crypto-device/25307f22-e5a8-4ea2-b7ca-79f5c3bebc3c
...

A human readable VQN is helpful to maintain/debug/distinguish.
Note that this section only defines the "VQN" schema.
For a process, the following two are both fine:
~# ./foo --full-url virtio-rdma://192.168.1.100:8549/blk-device/nvme-pool/849a39ad-8d7b-4a7a-adb6-e7407ace532c
~# ./foo --transport rdma --address 192.168.1.100 --port 8549
  --tvqn blk-device/hdd-pool/238151a7-acd7-4621-bbdf-382ddbccb6a1

Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
---
 transport-fabrics.tex | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/transport-fabrics.tex b/transport-fabrics.tex
index d10be2a..54d7558 100644
--- a/transport-fabrics.tex
+++ b/transport-fabrics.tex
@@ -30,3 +30,18 @@ \section{Virtio Over Fabrics}\label{sec:Virtio Transport Options / Virtio Over F
 which executes the bulk data transport on virtio devices.
 \item The arrival of data on the Virtio-oF queue indicates that a notification has arrived.
 \end{itemize}
+
+
+\subsection{Virtio-oF Qualified Name}\label{sec:Virtio Transport Options / Virtio Over Fabrics / Virtio-oF Qualified Name}
+Virtio-oF Qualified Names (VQNs) are used to uniquely describe a Virtio-oF initiator
+or a Virtio-oF target for identification.
+
+A VQN is encoded as a string of Unicode characters with the following properties:
+
+\begin{itemize}
+\item The encoding is UTF-8 (refer to RFC 3629).
+\item The characters dash('-'), dot ('.') and slash('/') are used in formatting.
+\item The string is NUL terminated.
+\item The maximum name is 256 bytes in length, including the NUL character.
+\item There is no strict style limitation.
+\end{itemize}
-- 
2.25.1