RE: [PATCH] virtio-net: Fix VIRTIO_NET_F_GUEST_HDRLEN feature definition.

Requesting the TC vote.
Fixes: https://github.com/oasis-tcs/virtio-spec/issues/72

>-----Original Message-----
>From:  <> On Behalf Of Vitaly
>Mireyno
>Sent: Monday, 24 February, 2020 10:15
>To: 
>Cc: Michael S. Tsirkin <>; Jason Wang <>
>Subject: [EXT] [virtio-comment] [PATCH] virtio-net: Fix VIRTIO_NET_F_GUEST_HDRLEN feature
>definition.
>
>External Email
>
>----------------------------------------------------------------------
>Fix driver and device requirements with regards to the VIRTIO_NET_F_GUEST_HDRLEN feature -
>'hdr_len' must be accurate only for TSO/UFO packets.
>
>
>Signed-off-by: Vitaly Mireyno <>
>---
> content.tex | 4 ++++
> 1 file changed, 4 insertions(+)
>
>diff --git a/content.tex b/content.tex
>index b91a132..2f71f8f 100644
>--- a/content.tex
>+++ b/content.tex
>@@ -3354,10 +3354,12 @@ \subsubsection{Packet Transmission}\label{sec:Device Types / Network
>Device / De  been negotiated:
> \begin{itemize}
> \item If the VIRTIO_NET_F_GUEST_HDRLEN feature has been negotiated,
>+	and \field{gso_type} differs from VIRTIO_NET_HDR_GSO_NONE,
> 	the driver MUST set \field{hdr_len} to a value equal to the length
> 	of the headers, including the transport header.
>
> \item If the VIRTIO_NET_F_GUEST_HDRLEN feature has not been negotiated,
>+	or \field{gso_type} is VIRTIO_NET_HDR_GSO_NONE,
> 	the driver SHOULD set \field{hdr_len} to a value
> 	not less than the length of the headers, including the transport
> 	header.
>@@ -3379,6 +3381,7 @@ \subsubsection{Packet Transmission}\label{sec:Device Types / Network
>Device / De  been negotiated:
> \begin{itemize}
> \item If the VIRTIO_NET_F_GUEST_HDRLEN feature has been negotiated,
>+	and \field{gso_type} differs from VIRTIO_NET_HDR_GSO_NONE,
> 	the device MAY use \field{hdr_len} as the transport header size.
>
> 	\begin{note}
>@@ -3387,6 +3390,7 @@ \subsubsection{Packet Transmission}\label{sec:Device Types / Network
>Device / De
> 	\end{note}
>
> \item If the VIRTIO_NET_F_GUEST_HDRLEN feature has not been negotiated,
>+	or \field{gso_type} is VIRTIO_NET_HDR_GSO_NONE,
> 	the device MAY use \field{hdr_len} only as a hint about the
> 	transport header size.
> 	The device MUST NOT rely on \field{hdr_len} to be correct.
>--
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