[PATCH 1/2] virtio-net: rephrase devconf fields description

[Victor Kaplansky <victork@redhat.com>]

Clarify general description of the mac, status and
max_virtqueue_pairs fields. Specifically, the old description is
vague about configuration layout and fields offsets when some of
the fields are non valid.

Also mac was described as driver-read-only, while actually it can
be modified through legacy interface.

Signed-off-by: Victor Kaplansky <victork@redhat.com>
---
 content.tex | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/content.tex b/content.tex
index d989d98..37e6a18 100644
--- a/content.tex
+++ b/content.tex
@@ -3115,23 +3115,14 @@ were needed.
 \subsection{Device configuration layout}\label{sec:Device Types / Network Device / Device configuration layout}
 \label{sec:Device Types / Block Device / Feature bits / Device configuration layout}
 
-Three driver-read-only configuration fields are currently defined. The \field{mac} address field
-always exists (though is only valid if VIRTIO_NET_F_MAC is set), and
-\field{status} only exists if VIRTIO_NET_F_STATUS is set. Two
-read-only bits (for the driver) are currently defined for the status field:
-VIRTIO_NET_S_LINK_UP and VIRTIO_NET_S_ANNOUNCE.
+
+The following configuration fields are currently defined:
 
 \begin{lstlisting}
 #define VIRTIO_NET_S_LINK_UP     1
 #define VIRTIO_NET_S_ANNOUNCE    2
 \end{lstlisting}
 
-The following driver-read-only field, \field{max_virtqueue_pairs} only exists if
-VIRTIO_NET_F_MQ is set. This field specifies the maximum number
-of each of transmit and receive virtqueues (receiveq1\ldots receiveqN
-and transmitq1\ldots transmitqN respectively) that can be configured once VIRTIO_NET_F_MQ
-is negotiated.
-
 \begin{lstlisting}
 struct virtio_net_config {
         u8 mac[6];
@@ -3140,6 +3131,26 @@ struct virtio_net_config {
 };
 \end{lstlisting}
 
+\begin{description}
+
+\item [\field{mac}] is MAC address assigned by the device and is valid
+    only if VIRTIO_NET_F_MAC is set.
+
+\item [\field{status}] consists of two driver-read-only status
+    bits: VIRTIO_NET_S_LINK_UP and VIRTIO_NET_S_ANNOUNCE and is valid only
+    if VIRTIO_NET_F_STATUS is set.
+
+
+\item [\field{max_virtqueue_pairs}] tells the driver the maximum
+    number of each of virtqueues (receiveq1\ldots receiveqN and
+    transmitq1\ldots transmitqN respectively) that can be configured
+    on the device once VIRTIO_NET_F_MQ is negotiated.
+    \field{max_virtqueue_pairs} is valid only if VIRTIO_NET_F_MQ is
+    set and should not be modified by the driver.
+
+\end{description}
+
+
 \devicenormative{\subsubsection}{Device configuration layout}{Device Types / Network Device / Device configuration layout}
 
 The device MUST set \field{max_virtqueue_pairs} to between 1 and 0x8000 inclusive,
-- 
--Victor