Document as used by Linux.
Fixes: https://github.com/oasis-tcs/virtio-spec/issues/59
Signed-off-by: Michael S. Tsirkin
Reviewed-by: Cornelia Huck
---
changes from v2:
fix up units
actually there's no way for driver to know that link up
changed: it might have changed back.
make the device requirement a weaker "SHOULD" and instead
ask that driver re-read on each config change notification
content.tex | 39 +++
1 file changed, 39 insertions(+)
diff --git a/content.tex b/content.tex
index d68cfaf..f7a6971 100644
--- a/content.tex
+++ b/content.tex
@@ -2823,6 +2823,7 @@ \subsection{Feature bits}\label{sec:Device Types /
Network Device / Feature bits
\item[VIRTIO_NET_F_STANDBY(62)] Device may act as a standby for a primary
device with the same MAC address.
+\item[VIRTIO_NET_F_SPEED_DUPLEX(63)] Device reports speed and duplex.
\end{description}
\subsubsection{Feature bit requirements}\label{sec:Device Types / Network
Device / Feature bits / Feature bit requirements}
@@ -2882,12 +2883,28 @@ \subsection{Device configuration
layout}\label{sec:Device Types / Network Device
VIRTIO_NET_F_MTU is set. This field specifies the maximum MTU for the driver to
use.
+The following two fields, \field{speed} and \field{duplex}, only
+exist if VIRTIO_NET_F_SPEED_DUPLEX is set.
+
+\field{speed} contains the device speed, in units of 1 MBit per
+second, 0 to 0x7, or 0xf for unknown speed.
+
+\field{duplex} has the values of 0x00 for full duplex, 0x01 for
+half duplex and 0xff for unknown duplex state.
+
+Both \field{speed} and \field{duplex} can change, thus the driver
+is expected to re-read these values after receiving a
+configuration change notification.
+
\begin{lstlisting}
struct virtio_net_config {
u8 mac[6];
le16 status;
le16 max_virtqueue_pairs;
le16 mtu;
+le32 speed;
+u8 duplex;
+
};
\end{lstlisting}
@@ -2916,6 +2933,19 @@ \subsection{Device configuration
layout}\label{sec:Device Types / Network Device
If the driver negotiates the VIRTIO_NET_F_STANDBY feature, the device MAY act
as a standby device for a primary device with the same MAC address.
+If VIRTIO_NET_F_SPEED_DUPLEX has been negotiated, \field{speed}
+MUST contain the device speed, in units of 1 MBit per second, 0 to
+0x7, or 0xf for unknown.
+
+If VIRTIO_NET_F_SPEED_DUPLEX has been negotiated, \field{duplex}
+MUST have the values of 0x00 for full duplex, 0x01 for half
+duplex, or 0xff for unknown.
+
+If VIRTIO_NET_F_SPEED_DUPLEX and VIRTIO_NET_F_STATUS have both
+been negotiated, the device SHOULD NOT change the \field{speed} and
+\field{duplex} fields as long as VIRTIO_NET_S_LINK_UP is set in
+the \field{status}.
+
\drivernormative{\subsubsection}{Device configuration layout}{Device Types /
Network Device / Device configuration layout}
A driver SHOULD negotiate VIRTIO_NET_F_MAC if the device offers it.
@@ -2940,6 +2970,15 @@ \subsection{Device configuration
layout}\label{sec:Device Types / Network Device
A driver SHOULD negotiate the VIRTIO_NET_F_STANDBY feature if the device
offers it.
+If VIRTIO_NET_F_SPEED_DUPLEX has been negotiated,
+the driver MUST treat any value of \field{speed} above
+0x7fff as well as any value of \field{duplex} not
+matching 0x00 or 0x01 as an unknown value.
+
+If VIRTIO_NET_F_SPEED_DUPLEX has been negotiated, the driver
+SHOULD re-read \field{speed} and \field{duplex} after a
+configuration change notification.
+
\subsubsection{Legacy Interface: Device configuration layout}\label{sec:Device
Types / Network Device / Device configuration layout / Legacy Interface: Device
configuration layout}
\label{sec:Device Types / Block Device / Feature bits / Device configuration
layout / Legacy Interface: Device configuration layout}
When using the legacy interface, transitional devices and drivers
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