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Subject: Re: [PATCH v6] virtio-net: support inner header hash
On Tue, Jan 03, 2023 at 10:25:18PM +0800, Heng Qi wrote: > If the tunnel is used to encapsulate the packets, the hash calculated > using the outer header of the receive packets is always fixed for the > same flow packets, i.e. they will be steered to the same receive queue. > > We add a feature bit VIRTIO_NET_F_HASH_TUNNEL and related bitmasks > in \field{hash_types}, which instructs the device to calculate the > hash using the inner headers of tunnel-encapsulated packets. Besides, > values in \field{hash_report_tunnel} are added to report tunnel types. > > Fixes: https://github.com/oasis-tcs/virtio-spec/issues/151 > > Reviewed-by: Jason Wang <jasowang@redhat.com> > Signed-off-by: Heng Qi <hengqi@linux.alibaba.com> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > --- > v5: > 1. Fix some syntax and capitalization issues. @Michael S. Tsirkin > 2. Use encapsulated/encaptulation uniformly. @Michael S. Tsirkin > 3. Move the links to introduction section. @Michael S. Tsirkin > 4. Clarify some sentences. @Michael S. Tsirkin > > v4: > 1. Clarify some paragraphs. @Cornelia Huck > 2. Fix the u8 type. @Cornelia Huck > > v3: > 1. Rename VIRTIO_NET_F_HASH_GRE_VXLAN_GENEVE_INNER to VIRTIO_NET_F_HASH_TUNNEL. @Jason Wang > 2. Make things clearer. @Jason Wang @Michael S. Tsirkin > 3. Keep the possibility to use inner hash for automatic receive steering. @Jason Wang > 4. Add the "Tunnel packet" paragraph to avoid repeating the GRE etc. many times. @Michael S. Tsirkin > > v2: > 1. Add a feature bit for GRE/VXLAN/GENEVE inner hash. @Jason Wang > 2. Chang \field{hash_tunnel} to \field{hash_report_tunnel}. @Jason Wang, @Michael S. Tsirkin > > v1: > 1. Remove the patch for the bitmask fix. @Michael S. Tsirkin > 2. Clarify some paragraphs. @Jason Wang > 3. Add \field{hash_tunnel} and VIRTIO_NET_HASH_REPORT_GRE. @Yuri Benditovich > > content.tex | 193 +++++++++++++++++++++++++++++++++++++++++++++-- > introduction.tex | 19 +++++ > 2 files changed, 205 insertions(+), 7 deletions(-) > > diff --git a/content.tex b/content.tex > index e863709..89b0039 100644 > --- a/content.tex > +++ b/content.tex > @@ -3084,6 +3084,9 @@ \subsection{Feature bits}\label{sec:Device Types / Network Device / Feature bits > \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control > channel. > > +\item[VIRTIO_NET_F_HASH_TUNNEL(52)] Device supports inner > + header hash for GRE, VXLAN and GENEVE tunnel-encapsulated packets. > + > \item[VIRTIO_NET_F_NOTF_COAL(53)] Device supports notifications coalescing. > > \item[VIRTIO_NET_F_GUEST_USO4 (54)] Driver can receive USOv4 packets. > @@ -3095,7 +3098,8 @@ \subsection{Feature bits}\label{sec:Device Types / Network Device / Feature bits > to several segments when each of these smaller packets has UDP header. > > \item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-packet hash > - value and a type of calculated hash. > + value, a type of calculated hash, and, if VIRTIO_NET_F_HASH_TUNNEL > + is negotiated, a encapsulation packet type. an encapsulation > > \item[VIRTIO_NET_F_GUEST_HDRLEN(59)] Driver can provide the exact \field{hdr_len} > value. Device benefits from knowing the exact header length. > @@ -3140,6 +3144,7 @@ \subsubsection{Feature bit requirements}\label{sec:Device Types / Network Device > \item[VIRTIO_NET_F_NOTF_COAL] Requires VIRTIO_NET_F_CTRL_VQ. > \item[VIRTIO_NET_F_RSC_EXT] Requires VIRTIO_NET_F_HOST_TSO4 or VIRTIO_NET_F_HOST_TSO6. > \item[VIRTIO_NET_F_RSS] Requires VIRTIO_NET_F_CTRL_VQ. > +\item[VIRTIO_NET_F_HASH_TUNNEL] Requires VIRTIO_NET_F_CTRL_VQ. > \end{description} > > \subsubsection{Legacy Interface: Feature bits}\label{sec:Device Types / Network Device / Feature bits / Legacy Interface: Feature bits} > @@ -3386,7 +3391,8 @@ \subsection{Device Operation}\label{sec:Device Types / Network Device / Device O > le16 num_buffers; > le32 hash_value; (Only if VIRTIO_NET_F_HASH_REPORT negotiated) > le16 hash_report; (Only if VIRTIO_NET_F_HASH_REPORT negotiated) > - le16 padding_reserved; (Only if VIRTIO_NET_F_HASH_REPORT negotiated) > + u8 hash_report_tunnel; (Only if VIRTIO_NET_F_HASH_REPORT negotiated, only valid of VIRTIO_NET_F_HASH_TUNNEL negotiated) > + u8 padding_reserved; (Only if VIRTIO_NET_F_HASH_REPORT negotiated) > }; > \end{lstlisting} > > @@ -3837,7 +3843,8 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network > A device attempts to calculate a per-packet hash in the following cases: > \begin{itemize} > \item The feature VIRTIO_NET_F_RSS was negotiated. The device uses the hash to determine the receive virtqueue to place incoming packets. > -\item The feature VIRTIO_NET_F_HASH_REPORT was negotiated. The device reports the hash value and the hash type with the packet. > +\item The feature VIRTIO_NET_F_HASH_REPORT was negotiated. The device reports the hash value and the hash type. If additionally > +VIRTIO_NET_F_HASH_TUNNEL was negotiated, the device reports the encapsulation type as well. > \end{itemize} > > If the feature VIRTIO_NET_F_RSS was negotiated: > @@ -3863,8 +3870,38 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network > \ref{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode / Hash calculation}. > \end{itemize} > > +\subparagraph{Tunnel/Encapsulated packet} > +\label{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / Tunnel/Encapsulated packet} > +A tunnel packet is encapsulated from the original packet based on the tunneling > +protocol (only a single level of encapsulation is currently supported), and the > +packet contains an outer header and an inner header. The device calculates the > +hash over over either >the inner header or outer header, or the outer header > and uses the hash to determine the > +receive virtqueue to place incoming encapsulated packet. "and uses the hash" does not belong here, it does not have to be used like this e.g. if RSS if off. > + > +When the feature VIRTIO_NET_F_HASH_TUNNEL is negotiated and the encapsulation > +type the encapsulation type seems vague. maybe "the corresponding encapsulation type". > is set in \field{hash_types}, the hash for specific type of encapsulated > +packet is calculated over the inner as opposed to outer header. Supported > +encapsulation types are listed in \ref{sec:Device Types / Network Device / > +Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / > +Supported/enabled hash types}. > + > +If both VIRTIO_NET_F_REPORT and VIRTIO_NET_F_HASH_TUNNEL are negotiated, > +the device supports can support > inner hash calculation for \hyperref[intro:GRE]{[GRE]}, > +\hyperref[intro:VXLAN]{[VXLAN]} and \hyperref[intro:GENEVE]{[GENEVE]} > +encapsulated packets, and the corresponding encapsulation type in > +\field{hash_types} is VIRTIO_NET_HASH_TYPE_{GRE, VXLAN, GENEVE}_INNER. .. respectively > +Besides, the value in \field{hash_report_tunnel} is > +VIRTIO_NET_HASH_REPORT_{GRE, VXLAN, GENEVE}. Besides what? and it can also be set to NONE right? > + > +If VIRTIO_NET_F_REPORT is negotiated but VIRTIO_NET_F_HASH_TUNNEL is not > +negotiated, the device calculates the hash over the outer header, and > +\field{hash_report} reports the hash types. type > Besides, \field{hash_report_tunnel} > +is set to VIRTIO_NET_HASH_REPORT_TUNNEL_NONE. > + I don't think we can do this, you are retroactively adding requirements for existing devices without VIRTIO_NET_F_HASH_TUNNEL. this field is not valid. > \subparagraph{Supported/enabled hash types} > \label{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / Supported/enabled hash types} > +This paragraph relies on definitions from \hyperref[intro:IP]{[IP]}, > +\hyperref[intro:UDP]{[UDP]} and \hyperref[intro:TCP]{[TCP]}. > Hash types applicable for IPv4 packets: > \begin{lstlisting} > #define VIRTIO_NET_HASH_TYPE_IPv4 (1 << 0) > @@ -3884,6 +3921,22 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network > #define VIRTIO_NET_HASH_TYPE_UDP_EX (1 << 8) > \end{lstlisting} > > +If the feature VIRTIO_NET_F_HASH_TUNNEL is negotiated, the encapsulation > +hash type below indicates that the hash is calculated over the inner > +header of the encapsulated packet: > +Hash type applicable to inner payload of the gre-encapsulated packet > +\begin{lstlisting} > +#define VIRTIO_NET_HASH_TYPE_GRE_INNER (1 << 9) > +\end{lstlisting} > +Hash type applicable to inner payload of the vxlan-encapsulated packet > +\begin{lstlisting} > +#define VIRTIO_NET_HASH_TYPE_VXLAN_INNER (1 << 10) > +\end{lstlisting} > +Hash type applicable to inner payload of the geneve-encapsulated packet > +\begin{lstlisting} > +#define VIRTIO_NET_HASH_TYPE_GENEVE_INNER (1 << 11) > +\end{lstlisting} > + "Applicable for" not "applicable to". > \subparagraph{IPv4 packets} > \label{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / IPv4 packets} > The device calculates the hash on IPv4 packets according to 'Enabled hash types' bitmask as follows: > @@ -3975,15 +4028,125 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network > (see \ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / IPv6 packets without extension header}). > \end{itemize} > > +\subparagraph{Inner payload of the encapsulated packet} an encapsulated packet > +\label{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / Inner payload of the encapsulated packet} > +If the feature VIRTIO_NET_F_HASH_TUNNEL is negotiated and the corresponding > +encapsulation hash type is set in \field{hash_types}, the device calculates the > +inner header hash on the encapsulated packet (See \ref{sec:Device Types an encapsulated packet > +/ Network Device / Device Operation / Processing of Incoming Packets / > +Hash calculation for incoming packets / Tunnel/Encapsulated packet}) as follows: > + > +If the inner payload of the encapsulated packet is an IPv4 packet and 'Enabled hash types' > +bitmasks are set as follows: this is still confusing and agrammatical. original text says things like: The device calculates the hash on IPv4 packets according to 'Enabled hash types' bitmask as follows: adjust text accordingly. > +\begin{itemize} > + \item If VIRTIO_NET_HASH_TYPE_TCPv4 is set and the encapsulated packet has an inner > + TCPv4 header, the hash is calculated over the following fields: > + \begin{itemsize} > + \item inner Source IP address > + \item inner Destination IP address > + \item inner Source TCP port > + \item inner Destination TCP port > + \end{itemsize} > + \item Else if VIRTIO_NET_HASH_TYPE_UDPv4 is set and the encapsulated packet has an > + inner UDPv4 header, the hash is calculated over the following fields: > + \begin{itemsize} > + \item inner Source IP address > + \item inner Destination IP address > + \item inner Source UDP port > + \item inner Destination UDP port > + \end{itemize} > + \item Else if VIRTIO_NET_HASH_TYPE_IPv4 is set, the hash is calculated over the > + following fields: > + \begin{itemsize} > + \item inner Source IP address > + \item inner Destination IP address > + \end{itemsize} > + \item Else the device does not calculate the hash > +\end{itemize} > + > +If the inner payload of the encapsulated packet is an IPv6 packet without an extension > +header and 'Enabled hash types' bitmasks are set as follows: > +\begin{itemize} > + \item If VIRTIO_NET_HASH_TYPE_TCPv6 is set and the encapsulated packet has an inner > + TCPv6 header, the hash is calculated over the following fields: > + \begin{itemsize} > + \item inner Source IPv6 address > + \item inner Destination IPv6 address > + \item inner Source TCP port > + \item inner Destination TCP port > + \end{itemsize} > + \item Else if VIRTIO_NET_HASH_TYPE_UDPv6 is set and the encapsulated packet has an > + inner UDPv6 header, the hash is calculated over the following fields: > + \begin{itemsize} > + \item inner Source IPv6 address > + \item inner Destination IPv6 address > + \item inner Source UDP port > + \item inner Destination UDP port > + \end{itemize} > + \item Else if VIRTIO_NET_HASH_TYPE_IPv6 is set, the hash is calculated over the > + following fields: > + \begin{itemsize} > + \item inner Source IPv6 address > + \item inner Destination IPv6 address > + \end{itemsize} > + \item Else the device does not calculate the hash > +\end{itemize} > + > +If the inner payload of the encapsulated packet is an IPv6 packet with an extension header > +and 'Enabled hash types' bitmasks are set as follows: > +\begin{itemsize} > + \item If VIRTIO_NET_HASH_TYPE_TCP_EX is set and the encapsulated packet has an inner > + TCPv6 header, the hash is calculated over the following fields: > + \begin{itemize} > + \item Home address from the home address option in the inner IPv6 destination > + options header. If the inner extension header is not present, use the > + inner Source IPv6 address. > + \item IPv6 address that is contained in the Routing-Header-Type-2 from the > + associated inner extension header. If the inner extension header is not > + present, use the inner Destination IPv6 address. > + \item inner Source TCP port > + \item inner Destination TCP port > + \end{itemize} > + \item Else if VIRTIO_NET_HASH_TYPE_UDP_EX is set and the encapsulated packet has an inner > + UDPv6 header, the hash is calculated over the following fields: > + \begin{itemsize} > + \item Home address from the home address option in the inner IPv6 destination > + options header. If the inner extension header is not present, use the > + inner Source IPv6 address. > + \item IPv6 address that is contained in the Routing-Header-Type-2 from the > + associated inner extension header. If the inner extension header is not > + present, use the inner Destination IPv6 address. > + \item inner Source UDP port > + \item inner Destination UDP port > + \end{itemize} > + \item Else if VIRTIO_NET_HASH_TYPE_IP_EX is set, the hash is calculated over the > + following fields: > + \begin{itemsize} > + \item Home address from the home address option in the inner IPv6 destination > + options header. If the inner extension header is not present, use the > + inner Source IPv6 address. > + \item IPv6 address that is contained in the Routing-Header-Type-2 from the > + associated inner extension header. If the inner extension header is not > + present, use the inner Destination IPv6 address. > + \end{itemize} > + \item Else skip the inner IPv6 extension header and calculate the inner header hash as > + defined for an encapsulated packet whose inner payload is an IPv6 packet without > + an extension header. > +\end{itemsize} > + > \paragraph{Hash reporting for incoming packets} > \label{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash reporting for incoming packets} > > -If VIRTIO_NET_F_HASH_REPORT was negotiated and > - the device has calculated the hash for the packet, the device fills \field{hash_report} with the report type of calculated hash > -and \field{hash_value} with the value of calculated hash. > +If VIRTIO_NET_F_HASH_REPORT was negotiated and the device has calculated the > +hash for the packet, the device fills \field{hash_report} with the report type > +of calculated hash, and \field{hash_value} with the value of calculated hash. > +Also, if VIRTIO_NET_F_HASH_TUNNEL was negotiated, the device needs to fill > +\field{hash_report_tunnel} with the report type of the encapsulated packet, and > +it is set to VIRTIO_NET_HASH_REPORT_TUNNEL_NONE for the unencapsulated packet. > > If VIRTIO_NET_F_HASH_REPORT was negotiated but due to any reason the > -hash was not calculated, the device sets \field{hash_report} to VIRTIO_NET_HASH_REPORT_NONE. > +hash was not calculated, the device sets \field{hash_report} to VIRTIO_NET_HASH_REPORT_NONE, > +and sets \field{hash_report_tunnel} to VIRTIO_NET_HASH_REPORT_TUNNEL_NONE. > > Possible values that the device can report in \field{hash_report} are defined below. > They correspond to supported hash types defined in > @@ -4005,6 +4168,22 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network > #define VIRTIO_NET_HASH_REPORT_UDPv6_EX 9 > \end{lstlisting} > > +If \field{hash_report} differs from VIRTIO_NET_HASH_REPORT_NONE, > +\field{hash_report_tunnel} can report the type of the encapsulated > +packet to the driver over the inner header hash calculation. > +Possible values that the device can report in \field{hash_report_tunnel} > +are defined below: > + > +\begin{lstlisting} > +#define VIRTIO_NET_HASH_REPORT_TUNNEL_NONE 0 > +#define VIRTIO_NET_HASH_REPORT_GRE 1 > +#define VIRTIO_NET_HASH_REPORT_VXLAN 2 > +#define VIRTIO_NET_HASH_REPORT_GENEVE 3 > +\end{lstlisting} > + > +They correspond to supported hash types defined in > +\ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / Supported/enabled hash types}. > + > \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue} > > The driver uses the control virtqueue (if VIRTIO_NET_F_CTRL_VQ is > diff --git a/introduction.tex b/introduction.tex > index 287c5fc..ff01a9b 100644 > --- a/introduction.tex > +++ b/introduction.tex > @@ -98,6 +98,25 @@ \section{Normative References}\label{sec:Normative References} > \phantomsection\label{intro:SEC1}\textbf{[SEC1]} & > Standards for Efficient Cryptography Group(SECG), ``SEC1: Elliptic Cureve Cryptography'', Version 1.0, September 2000. > \newline\url{https://www.secg.org/sec1-v2.pdf}\\ > + \phantomsection\label{intro:GRE}\textbf{[GRE]} & > + Generic Routing Encapsulation > + \newline\url{https://datatracker.ietf.org/doc/rfc2784/}\\ > + \phantomsection\label{intro:VXLAN}\textbf{[VXLAN]} & > + Virtual eXtensible Local Area Network > + \newline\url{https://datatracker.ietf.org/doc/rfc7348/}\\ > + \phantomsection\label{intro:GENEVE}\textbf{[GENEVE]} & > + Generic Network Virtualization Encapsulation > + \newline\url{https://datatracker.ietf.org/doc/rfc8926/}\\ > + \phantomsection\label{intro:IP}\textbf{[IP]} & > + INTERNET PROTOCOL > + \newline\url{https://www.rfc-editor.org/rfc/rfc791}\\ > + \phantomsection\label{intro:UDP}\textbf{[UDP]} & > + User Datagram Protocol > + \newline\url{https://www.rfc-editor.org/rfc/rfc768}\\ > + \phantomsection\label{intro:TCP}\textbf{[TCP]} & > + TRANSMISSION CONTROL PROTOCOL > + \newline\url{https://www.rfc-editor.org/rfc/rfc793}\\ > + > > \end{longtable} > > -- > 2.19.1.6.gb485710b
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