Re: [virtio-comment] [PATCH] content: document speed, duplex

[Yan Vugenfirer <yvugenfi@redhat.com>]

Hi Michael,

Currently there are also link up\down notifications. Should we add something like:
âThe driver should re-read the speed and duplex configuration after receiving link up notificationâ.
What do you think?

Best regards,
Yan.

> On 27 Nov 2019, at 3:07 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> 
> Document as used by Linux.
> 
> Fixes: https://github.com/oasis-tcs/virtio-spec/issues/59
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> ---
> content.tex | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
> 
> diff --git a/content.tex b/content.tex
> index 9157717..6acbb19 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -2899,6 +2899,7 @@ \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}
> @@ -2958,12 +2959,27 @@ \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 MByte, 0
> +to 0x7ffffffff, or 0xfffffffff for unknown speed.
> +
> +\field{duplex} has the values of 0x00 for full duplex, 0x01 for
> +half duplex and 0xff for unknown duplex state.
> +
> +Neither \field{speed} nor \field{duplex} changes as long as
> +VIRTIO_NET_S_LINK_UP is set.
> +
> \begin{lstlisting}
> struct virtio_net_config {
>         u8 mac[6];
>         le16 status;
>         le16 max_virtqueue_pairs;
>         le16 mtu;
> +        le32 speed;
> +        u8 duplex;
> +
> };
> \end{lstlisting}
> 
> @@ -2992,6 +3008,18 @@ \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 MByte, 0 to
> +0x7ffffffff, or 0xfffffffff 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 has been negotiated, the device MUST
> +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.
> @@ -3016,6 +3044,11 @@ \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
> +0x7fffffff as well as any value of \field{duplex} not
> +matching 0x00 or 0x01 as an unknown value.
> +
> \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
> -- 
> MST
> 
> 
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