From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-comment-return-1071-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 61A03985EC1 for ; Wed, 19 Feb 2020 14:56:19 +0000 (UTC) Date: Wed, 19 Feb 2020 09:56:04 -0500 From: "Michael S. Tsirkin" Message-ID: <20200219095236-mutt-send-email-mst@kernel.org> References: <20200219075337.23191-1-yuri.benditovich@daynix.com> <20200219075337.23191-2-yuri.benditovich@daynix.com> <20200219040122-mutt-send-email-mst@kernel.org> <1841911156.7222325.1582110433680.JavaMail.zimbra@redhat.com> <20200219092917-mutt-send-email-mst@kernel.org> <1785864968.7261240.1582123777151.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 In-Reply-To: <1785864968.7261240.1582123777151.JavaMail.zimbra@redhat.com> Subject: Re: [virtio-comment] Re: [PATCH v4 1/1] virtio-net: Define per-packet hash reporting feature Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline To: Yuri Benditovich Cc: Yuri Benditovich , virtio-comment@lists.oasis-open.org List-ID: On Wed, Feb 19, 2020 at 09:49:37AM -0500, Yuri Benditovich wrote: >=20 >=20 > =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81= =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2= =94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94= =81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81= =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2= =94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94= =81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81= =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2= =94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94= =81=E2=94=81=E2=94=81=E2=94=81=E2=94=81 >=20 > From: "Michael S. Tsirkin" > To: "Yuri Benditovich" > Cc: "Yuri Benditovich" , > virtio-comment@lists.oasis-open.org > Sent: Wednesday, February 19, 2020 4:35:49 PM > Subject: Re: [virtio-comment] Re: [PATCH v4 1/1] virtio-net: Define > per-packet hash reporting feature >=20 > On Wed, Feb 19, 2020 at 06:07:13AM -0500, Yuri Benditovich wrote: > > > > > > > =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94= =81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81= =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2= =94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94= =81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81= =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2= =94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94= =81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81= =E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81=E2= =94=81=E2=94=81=E2=94=81=E2=94=81=E2=94=81 > > > > From: "Michael S. Tsirkin" > > To: "Yuri Benditovich" > > Cc: virtio-comment@lists.oasis-open.org > > Sent: Wednesday, February 19, 2020 11:12:40 AM > > Subject: [virtio-comment] Re: [PATCH v4 1/1] virtio-net: Define > per-packet > > hash reporting feature > > > > On Wed, Feb 19, 2020 at 09:53:37AM +0200, Yuri Benditovich wrot= e: > > > Fixes: https://github.com/oasis-tcs/virtio-spec/issues/66 > > > Define respective feature bit for virtio-net. > > > Extend packet layout to populate hash value and type. > > > Move the definition of IP/TCP/UDP header fields to > > > calculate the hash out of RSS section to common network > > > device section. > > > > > > Signed-off-by: Yuri Benditovich > > > --- > > > content.tex | 347 > ++++++++++++++++++++++++++++++++++------------------ > > > 1 file changed, 229 insertions(+), 118 deletions(-) > > > > > > diff --git a/content.tex b/content.tex > > > index b91a132..d7d4e42 100644 > > > --- a/content.tex > > > +++ b/content.tex > > > @@ -2895,6 +2895,9 @@ \subsection{Feature bits}\label{sec:Dev= ice > Types / > > Network Device / Feature bits > > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address throug= h > control > > > channel. > > > =20 > > > +\item[VIRTIO_NET_F_HASH_REPORT(57)] Device can report per-pa= cket > hash > > > + value and a type of calculated hash. > > > + > > > \item[VIRTIO_NET_F_GUEST_HDRLEN(59)] Driver can provide the = exact > \field > > {hdr_len} > > > value. Device benefits from knowing the exact header len= gth. > > > =20 > > > @@ -2995,35 +2998,17 @@ \subsection{Device configuration layo= ut}\ > label > > {sec:Device Types / Network Device > > > le32 supported_hash_types; > > > }; > > > \end{lstlisting} > > > -\label{sec:Device Types / Network Device / Device configurat= ion > layout / > > RSS} > > > -Three following fields, \field{rss_max_key_size}, \field > > {rss_max_indirection_table_length} > > > -and \field{supported_hash_types} only exist if VIRTIO_NET_F_= RSS is > set. > > > +The following field, \field{rss_max_key_size} only exist if > > VIRTIO_NET_F_RSS or VIRTIO_NET_F_HASH_REPORT is set. > > > +It specifies the maximal supported length of RSS key in byte= s. > > > =20 > > > -Field \field{rss_max_key_size} specifies the maximal support= ed > length of > > RSS key in bytes. > > > +The following field, \field{rss_max_indirection_table_length= } only > exist > > if VIRTIO_NET_F_RSS is set. > > > +It specifies the maximal number of 16-bit entries in RSS > indirection > > table. > > > =20 > > > -Field \field{rss_max_indirection_table_length} specifies the > maximal > > number of 16-bit entries in RSS indirection table. > > > +The next field, \field{supported_hash_types} exists only if = the > device > > supports hash calculation, > > > +i.e. if VIRTIO_NET_F_RSS or VIRTIO_NET_F_HASH_REPORT is set. > > > =20 > > > -Field \field{supported_hash_types} contains the bitmask of > supported RSS > > hash types. > > > - > > > -Hash types applicable for IPv4 packets: > > > -\begin{lstlisting} > > > -#define VIRTIO_NET_RSS_HASH_TYPE_IPv4 (1 << 0) > > > -#define VIRTIO_NET_RSS_HASH_TYPE_TCPv4 (1 << 1) > > > -#define VIRTIO_NET_RSS_HASH_TYPE_UDPv4 (1 << 2) > > > -\end{lstlisting} > > > -Hash types applicable for IPv6 packets without extension hea= ders > > > -\begin{lstlisting} > > > -#define VIRTIO_NET_RSS_HASH_TYPE_IPv6 (1 << 3) > > > -#define VIRTIO_NET_RSS_HASH_TYPE_TCPv6 (1 << 4) > > > -#define VIRTIO_NET_RSS_HASH_TYPE_UDPv6 (1 << 5) > > > -\end{lstlisting} > > > -Hash types applicable for IPv6 packets with extension header= s > > > -\begin{lstlisting} > > > -#define VIRTIO_NET_RSS_HASH_TYPE_IP_EX (1 << 6) > > > -#define VIRTIO_NET_RSS_HASH_TYPE_TCP_EX (1 << 7) > > > -#define VIRTIO_NET_RSS_HASH_TYPE_UDP_EX (1 << 8) > > > -\end{lstlisting} > > > -For the exact meaning of VIRTIO_NET_RSS_HASH_TYPE_ flags see= \ref > > {sec:Device Types / Network Device / Device Operation / Control > Virtqueue / > > Receive-side scaling (RSS) / RSS hash types}. > > > +Field \field{supported_hash_types} contains the bitmask of > supported > > hash types. > > > +See \ref{sec:Device Types / Network Device / Device Operatio= n / > > Processing of Incoming Packets / Hash calculation for incoming > packets / > > Supported/enabled hash types} for details of supported hash typ= es. > > > =20 > > > \devicenormative{\subsubsection}{Device configuration layout= } > {Device > > Types / Network Device / Device configuration layout} > > > =20 > > > @@ -3048,7 +3033,7 @@ \subsection{Device configuration layout= }\ > label > > {sec:Device Types / Network Device > > > negotiated. > > > =20 > > > The device MUST set \field{rss_max_key_size} to at least 40,= if it > > offers > > > -VIRTIO_NET_F_RSS. > > > +VIRTIO_NET_F_RSS or VIRTIO_NET_F_HASH_REPORT. > > > =20 > > > The device MUST set \field{rss_max_indirection_table_length}= to at > least > > 128, if it offers > > > VIRTIO_NET_F_RSS. > > > @@ -3195,6 +3180,8 @@ \subsection{Device Operation}\label > {sec:Device > > Types / Network Device / Device O > > > le16 csum_start; > > > le16 csum_offset; > > > le16 num_buffers; > > > + le32 hash_value; (Only if VIRTIO_NET_F_HASH_REPORT > negotiated) > > > + le16 hash_type; (Only if VIRTIO_NET_F_HASH_REPORT > negotiated) > > > }; > > > > Just noticed this - it's a bit problematic as it might force > > compilers to add 2 bytes of padding at the end. Let's add extra= 2 > bytes > > of padding explicitly? > > > > OK, no problem > > > > > > > > > > > \end{lstlisting} > > > =20 > > > @@ -3517,6 +3504,12 @@ \subsubsection{Processing of Incoming > Packets}\ > > label{sec:Device Types / Network > > > =20 > > > \end{enumerate} > > > =20 > > > +If applicable, the device calculates per-packet hash for inc= oming > > packets as > > > +defined in \ref{sec:Device Types / Network Device / Device > Operation / > > Processing of Incoming Packets / Hash calculation for incoming > packets}. > > > + > > > +If applicable, the device reports hash information for incom= ing > packets > > as > > > +defined in \ref{sec:Device Types / Network Device / Device > Operation / > > Processing of Incoming Packets / Hash reporting for incoming > packets}. > > > + > > > \devicenormative{\paragraph}{Processing of Incoming Packets} > {Device > > Types / Network Device / Device Operation / Processing of Incom= ing > Packets} > > > \label{devicenormative:Device Types / Network Device / Devic= e > Operation > > / Processing of Packets}%old label for latexdiff > > > =20 > > > @@ -3619,6 +3612,181 @@ \subsubsection{Processing of Incoming > Packets}\ > > label{sec:Device Types / Network > > > If neither VIRTIO_NET_HDR_F_NEEDS_CSUM nor > > > VIRTIO_NET_HDR_F_DATA_VALID is set, the driver MUST NOT > > > rely on the packet checksum being correct. > > > + > > > +\paragraph{Hash calculation for incoming packets} > > > +\label{sec:Device Types / Network Device / Device Operation = / > Processing > > of Incoming Packets / Hash calculation for incoming packets} > > > + > > > +A device attempts to calculate a per-packet hash in the foll= owing > cases: > > > +\begin{itemize} > > > +\item The feature VIRTIO_NET_F_RSS was negotiated. The devic= e uses > the > > hash to determine the receive virtqueue to place incoming packe= ts. > > > +\item The feature VIRTIO_NET_F_HASH_REPORT was negotiated. T= he > device > > reports the hash value and the hash type with the packet. > > > +\end{itemize} > > > + > > > +If the feature VIRTIO_NET_F_RSS was negotiated: > > > +\begin{itemize} > > > +\item The device uses \field{hash_types} of the > virtio_net_rss_config > > structure as 'Enabled hash types' bitmask. > > > +\item The device uses a key as defined in \field{hash_key_da= ta} > and \ > > field{hash_key_length} of the virtio_net_rss_config structure (= see > > > +\ref{sec:Device Types / Network Device / Device Operation / > Control > > Virtqueue / Receive-side scaling (RSS) / Setting RSS parameters= }). > > > +\end{itemize} > > > + > > > +If the feature VIRTIO_NET_F_RSS was not negotiated: > > > +\begin{itemize} > > > +\item The device uses \field{hash_types} of the > virtio_net_hash_config > > structure as 'Enabled hash types' bitmask. > > > +\item The device uses a key as defined in \field{hash_key_da= ta} > and \ > > field{hash_key_length} of the virtio_net_hash_config structure = (see > > > +\ref{sec:Device Types / Network Device / Device Operation / > Control > > Virtqueue / Automatic receive steering in multiqueue mode / Has= h > > calculation}). > > > +\end{itemize} > > > + > > > +Note that if the device offers VIRTIO_NET_F_HASH_REPORT, eve= n if > it > > supports only one pair of virtqueues, it MUST support > > > +at least one of commands of VIRTIO_NET_CTRL_MQ class to conf= igure > > reported hash parameters: > > > +\begin{itemize} > > > +\item If the device offers VIRTIO_NET_F_RSS, it MUST support > > VIRTIO_NET_CTRL_MQ_RSS_CONFIG command per > > > + \ref{sec:Device Types / Network Device / Device Operation / > Control > > Virtqueue / Receive-side scaling (RSS) / Setting RSS parameters= }. > > > +\item Otherwise the device MUST support > VIRTIO_NET_CTRL_MQ_HASH_CONFIG > > command per > > > + \ref{sec:Device Types / Network Device / Device Operation / > Control > > Virtqueue / Automatic receive steering in multiqueue mode / Has= h > > calculation}. > > > +\end{itemize} > > > + > > > +\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} > > > +Hash types applicable for IPv4 packets: > > > +\begin{lstlisting} > > > +#define VIRTIO_NET_HASH_TYPE_IPv4 (1 << 0) > > > +#define VIRTIO_NET_HASH_TYPE_TCPv4 (1 << 1) > > > +#define VIRTIO_NET_HASH_TYPE_UDPv4 (1 << 2) > > > +\end{lstlisting} > > > +Hash types applicable for IPv6 packets without extension hea= ders > > > +\begin{lstlisting} > > > +#define VIRTIO_NET_HASH_TYPE_IPv6 (1 << 3) > > > +#define VIRTIO_NET_HASH_TYPE_TCPv6 (1 << 4) > > > +#define VIRTIO_NET_HASH_TYPE_UDPv6 (1 << 5) > > > +\end{lstlisting} > > > +Hash types applicable for IPv6 packets with extension header= s > > > +\begin{lstlisting} > > > +#define VIRTIO_NET_HASH_TYPE_IP_EX (1 << 6) > > > +#define VIRTIO_NET_HASH_TYPE_TCP_EX (1 << 7) > > > +#define VIRTIO_NET_HASH_TYPE_UDP_EX (1 << 8) > > > +\end{lstlisting} > > > + > > > +\subparagraph{IPv4 packets} > > > +\label{sec:Device Types / Network Device / Device Operation = / > Processing > > of Incoming Packets / Hash calculation for incoming packets / I= Pv4 > packets} > > > +The device calculates the hash on IPv4 packets according to > 'Enabled > > hash types' bitmask as follows: > > > +\begin{itemize} > > > +\item If VIRTIO_NET_HASH_TYPE_TCPv4 is set and the packet ha= s > > > +a TCP header, the hash is calculated over the following fiel= ds: > > > +\begin{itemize} > > > +\item Source IP address > > > +\item Destination IP address > > > +\item Source TCP port > > > +\item Destination TCP port > > > +\end{itemize} > > > +\item Else if VIRTIO_NET_HASH_TYPE_UDPv4 is set and the > > > +packet has a UDP header, the hash is calculated over the fol= lowing > > fields: > > > +\begin{itemize} > > > +\item Source IP address > > > +\item Destination IP address > > > +\item Source UDP port > > > +\item Destination UDP port > > > +\end{itemize} > > > +\item Else if VIRTIO_NET_HASH_TYPE_IPv4 is set, the hash is > > > +calculated over the following fields: > > > +\begin{itemize} > > > +\item Source IP address > > > +\item Destination IP address > > > +\end{itemize} > > > +\item Else the device does not calculate the hash > > > +\end{itemize} > > > + > > > +\subparagraph{IPv6 packets without extension header} > > > +\label{sec:Device Types / Network Device / Device Operation = / > Processing > > of Incoming Packets / Hash calculation for incoming packets / I= Pv6 > packets > > without extension header} > > > +The device calculates the hash on IPv6 packets without exten= sion > > > +headers according to 'Enabled hash types' bitmask as follows= : > > > +\begin{itemize} > > > +\item If VIRTIO_NET_HASH_TYPE_TCPv6 is set and the packet ha= s > > > +a TCPv6 header, the hash is calculated over the following fi= elds: > > > +\begin{itemize} > > > +\item Source IPv6 address > > > +\item Destination IPv6 address > > > +\item Source TCP port > > > +\item Destination TCP port > > > +\end{itemize} > > > +\item Else if VIRTIO_NET_HASH_TYPE_UDPv6 is set and the > > > +packet has a UDPv6 header, the hash is calculated over the > following > > fields: > > > +\begin{itemize} > > > +\item Source IPv6 address > > > +\item Destination IPv6 address > > > +\item Source UDP port > > > +\item Destination UDP port > > > +\end{itemize} > > > +\item Else if VIRTIO_NET_HASH_TYPE_IPv6 is set, the hash is > > > +calculated over the following fields: > > > +\begin{itemize} > > > +\item Source IPv6 address > > > +\item Destination IPv6 address > > > +\end{itemize} > > > +\item Else the device does not calculate the hash > > > +\end{itemize} > > > + > > > +\subparagraph{IPv6 packets with extension header} > > > +\label{sec:Device Types / Network Device / Device Operation = / > Processing > > of Incoming Packets / Hash calculation for incoming packets / I= Pv6 > packets > > with extension header} > > > +The device calculates the hash on IPv6 packets with extensio= n > > > +headers according to 'Enabled hash types' bitmask as follows= : > > > +\begin{itemize} > > > +\item If VIRTIO_NET_HASH_TYPE_TCP_EX is set and the packet > > > +has a TCPv6 header, the hash is calculated over the followin= g > fields: > > > +\begin{itemize} > > > +\item Home address from the home address option in the IPv6 > destination > > options header. If the extension header is not present, use the > Source IPv6 > > address. > > > +\item IPv6 address that is contained in the Routing-Header-T= ype-2 > from > > the associated extension header. If the extension header is not > present, > > use the Destination IPv6 address. > > > +\item Source TCP port > > > +\item Destination TCP port > > > +\end{itemize} > > > +\item Else if VIRTIO_NET_HASH_TYPE_UDP_EX is set and the > > > +packet has a UDPv6 header, the hash is calculated over the > following > > fields: > > > +\begin{itemize} > > > +\item Home address from the home address option in the IPv6 > destination > > options header. If the extension header is not present, use the > Source IPv6 > > address. > > > +\item IPv6 address that is contained in the Routing-Header-T= ype-2 > from > > the associated extension header. If the extension header is not > present, > > use the Destination IPv6 address. > > > +\item Source UDP port > > > +\item 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{itemize} > > > +\item Home address from the home address option in the IPv6 > destination > > options header. If the extension header is not present, use the > Source IPv6 > > address. > > > +\item IPv6 address that is contained in the Routing-Header-T= ype-2 > from > > the associated extension header. If the extension header is not > present, > > use the Destination IPv6 address. > > > +\end{itemize} > > > +\item Else skip IPv6 extension headers and calculate the has= h as > > > +defined for an IPv6 packet without extension headers > > > +(see \ref{sec:Device Types / Network Device / Device Operati= on / > > Processing of Incoming Packets / Hash calculation for incoming > packets / > > IPv6 packets without extension header}). > > > +\end{itemize} > > > + > > > +\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 devi= ce > fills \ > > field{hash_type} with the type of calculated hash > > > +and \field{hash_value} with the value of calculated hash. > > > + > > > +If VIRTIO_NET_F_HASH_REPORT was negotiated but due to any re= ason > the > > > +hash was not calculated, the device sets \field{hash_type} t= o > > VIRTIO_NET_HASH_REPORT_NONE. > > > + > > > +Possible values that the device can report in \field{hash_ty= pe} > are > > defined below. > > > +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} > > > +as follows: > > > + > > > +VIRTIO_NET_HASH_TYPE_XXX =3D 1 << (VIRTIO_NET_HASH_REPORT_XX= X - 1) > > > > > > So hash_type is the HASH_REPORT value then? That's quite confus= ing. > > Let's rename to hash_report? > > > > No problem to rename anything, but I'd like to do it one time. > > Currently meaningful hash report values are (1..9), 0 for none > > They correspond to bitmask of 9 bits for enabled/supported. > > It was possible to use the same definitions for enable/support/repo= rt > > but then reported kind of hash should be 4 bytes. > > As you anyway suggests padding at the end of the packet, we can do = that, > > i.e. add (32 bit hash + 32 bit type) >=20 > We can but it seems like a waste, does it not? padding can be used fo= r > something later ... >=20 > > Or if we stay with the values as they are now: > > values 0..9 - VIRTIO_NET_WHAT? >=20 > I thought that's VIRTIO_NET_HASH_REPORT_XXX >=20 > OK, this is exactly what is defined >=20 >=20 > > bits from 0 to 8 - VIRTIO_NET_WHAT? >=20 >=20 > and this one VIRTIO_NET_HASH_TYPE_XXX? >=20 > OK, this is also exactly what is defined >=20 Right I'm saying what's defined is fine, just call the fields consistently. >=20 >=20 > Generally what you did here is a bit unusual. Mostly we just define > bit numbers > #define VIRTIO_SCSI_F_INOUT 0 > #define VIRTIO_SCSI_F_HOTPLUG 1 > #define VIRTIO_SCSI_F_CHANGE 2 > #define VIRTIO_SCSI_F_T10_PI 3 >=20 >=20 > Value 0 of hash_report is "no hash calculated" and it does not > participate in support/enable mask. I did not want to > use value other than zero for "no hash". Oh right. > So you want bit 0 to be reserved (not used) in enable/support mask > and then to have all the VIRTIO_NET_HASH_TYPE_XXX to be > exactly 1 << VIRTIO_NET_HASH_REPORT_XXX? Just say... >=20 We can do that too but it's up to you really. So fixing the below you would say =09 bit 0 curresponding to value 1, =09 bit 1 corresponding to value 2 etc. =09 No bit corresponds to value 0 ? >=20 > and just say that bit numbers are from this table, with bit > 0 corresponding to the value 0, bit 1 to value 1 etc. >=20 >=20 > maybe that would have been easier on the eyes - I didn't try, > I'm not even sure. >=20 > But what you have is correct enough, we can always try to > improve the wording later. >=20 >=20 > > > > > > > + > > > +\begin{lstlisting} > > > +#define VIRTIO_NET_HASH_REPORT_NONE 0 > > > +#define VIRTIO_NET_HASH_REPORT_IPv4 1 > > > +#define VIRTIO_NET_HASH_REPORT_TCPv4 2 > > > +#define VIRTIO_NET_HASH_REPORT_UDPv4 3 > > > +#define VIRTIO_NET_HASH_REPORT_IPv6 4 > > > +#define VIRTIO_NET_HASH_REPORT_TCPv6 5 > > > +#define VIRTIO_NET_HASH_REPORT_UDPv6 6 > > > +#define VIRTIO_NET_HASH_REPORT_IPv6_EX 7 > > > +#define VIRTIO_NET_HASH_REPORT_TCPv6_EX 8 > > > +#define VIRTIO_NET_HASH_REPORT_UDPv6_EX 9 > > > +\end{lstlisting} > > > + > > > \subsubsection{Control Virtqueue}\label{sec:Device Types / N= etwork > > Device / Device Operation / Control Virtqueue} > > > =20 > > > The driver uses the control virtqueue (if VIRTIO_NET_F_CTRL_= VQ is > > > @@ -3896,6 +4064,7 @@ \subsubsection{Control Virtqueue}\label > {sec:Device > > Types / Network Device / Devi > > > #define VIRTIO_NET_CTRL_MQ 4 > > > #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET 0 (for autom= atic > receive > > steering) > > > #define VIRTIO_NET_CTRL_MQ_RSS_CONFIG 1 (for > configurable > > receive steering) > > > + #define VIRTIO_NET_CTRL_MQ_HASH_CONFIG 2 (for > configurable hash > > calculation) > > > \end{lstlisting} > > > =20 > > > If more than one multiqueue mode is negotiated, the resultin= g > device > > configuration is defined by the last command sent by the driver= . > > > @@ -3961,10 +4130,37 @@ \subsubsection{Control Virtqueue}\lab= el > > {sec:Device Types / Network Device / Devi > > > according to the native endian of the guest rather than > > > (necessarily when not using the legacy interface) little-end= ian. > > > =20 > > > +\subparagraph{Hash calculation}\label{sec:Device Types / Net= work > Device > > / Device Operation / Control Virtqueue / Automatic receive stee= ring > in > > multiqueue mode / Hash calculation} > > > +If VIRTIO_NET_F_HASH_REPORT was negotiated and the device us= es > automatic > > receive steering, > > > +the device MUST support a command to configure hash calculat= ion > > parameters. > > > + > > > +The driver provides parameters for hash calculation as follo= ws: > > > + > > > +\field{class} VIRTIO_NET_CTRL_MQ, \field{command} > > VIRTIO_NET_CTRL_MQ_HASH_CONFIG. > > > + > > > +The \field{command-specific-data} has following format: > > > +\begin{lstlisting} > > > +struct virtio_net_hash_config { > > > + le32 hash_types; > > > + le16 reserved[4]; > > > + u8 hash_key_length; > > > + u8 hash_key_data[hash_key_length]; > > > +}; > > > +\end{lstlisting} > > > +Field \field{hash_types} contains a bitmask of allowed hash = types > as > > > +defined in > > > +\ref{sec:Device Types / Network Device / Device Operation / > Processing > > of Incoming Packets / Hash calculation for incoming packets / > Supported/ > > enabled hash types}. > > > +Initially the device has all hash types disabled and reports= only > > VIRTIO_NET_HASH_REPORT_NONE. > > > + > > > +Field \field{reserved} MUST contain zeroes. It is defined to= make > the > > structure to match the layout of virtio_net_rss_config structur= e, > > > +defined in \ref{sec:Device Types / Network Device / Device > Operation / > > Control Virtqueue / Receive-side scaling (RSS)}. > > > + > > > +Fields \field{hash_key_length} and \field{hash_key_data} def= ine > the key > > to be used in hash calculation. > > > + > > > \paragraph{Receive-side scaling (RSS)}\label{sec:Device Type= s / > Network > > Device / Device Operation / Control Virtqueue / Receive-side sc= aling > (RSS)} > > > A device offers the feature VIRTIO_NET_F_RSS if it supports = RSS > receive > > steering with Toeplitz hash calculation and configurable parame= ters. > > > =20 > > > -A driver queries RSS capabilities of the device by reading d= evice > > configuration as defined in \ref{sec:Device Types / Network Dev= ice / > Device > > configuration layout / RSS} > > > +A driver queries RSS capabilities of the device by reading d= evice > > configuration as defined in \ref{sec:Device Types / Network Dev= ice / > Device > > configuration layout} > > > =20 > > > \subparagraph{Setting RSS parameters}\label{sec:Device Types= / > Network > > Device / Device Operation / Control Virtqueue / Receive-side sc= aling > (RSS) > > / Setting RSS parameters} > > > =20 > > > @@ -3981,7 +4177,8 @@ \subsubsection{Control Virtqueue}\label > {sec:Device > > Types / Network Device / Devi > > > }; > > > \end{lstlisting} > > > Field \field{hash_types} contains a bitmask of allowed hash = types > as > > > -defined in \ref{sec:Device Types / Network Device / Device > Operation / > > Control Virtqueue / Receive-side scaling (RSS) / RSS 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}. > > > =20 > > > Field \field{indirection_table_mask} is a mask to be applied= to > > > the calculated hash to produce an index in the > > > @@ -3995,93 +4192,7 @@ \subsubsection{Control Virtqueue}\labe= l > {sec:Device > > Types / Network Device / Devi > > > =20 > > > A driver sets \field{max_tx_vq} to inform a device how many > transmit > > virtqueues it may use (transmitq1\ldots transmitq \field{max_tx= _vq}). > > > =20 > > > -\subparagraph{RSS hash types}\label{sec:Device Types / Netwo= rk > Device / > > Device Operation / Control Virtqueue / Receive-side scaling (RS= S) / > RSS > > hash types} > > > - > > > -The device calculates the hash on IPv4 packets according to = the > > > -field \field{hash_types} of the virtio_net_rss_config struct= ure as > > follows: > > > -\begin{itemize} > > > -\item If VIRTIO_NET_RSS_HASH_TYPE_TCPv4 is set and the packe= t has > > > -a TCP header, the hash is calculated over the following fiel= ds: > > > -\begin{itemize} > > > -\item Source IP address > > > -\item Destination IP address > > > -\item Source TCP port > > > -\item Destination TCP port > > > -\end{itemize} > > > -\item Else if VIRTIO_NET_RSS_HASH_TYPE_UDPv4 is set and the > > > -packet has a UDP header, the hash is calculated over the fol= lowing > > fields: > > > -\begin{itemize} > > > -\item Source IP address > > > -\item Destination IP address > > > -\item Source UDP port > > > -\item Destination UDP port > > > -\end{itemize} > > > -\item Else if VIRTIO_NET_RSS_HASH_TYPE_IPv4 is set, the hash= is > > > -calculated over the following fields: > > > -\begin{itemize} > > > -\item Source IP address > > > -\item Destination IP address > > > -\end{itemize} > > > -\item Else the device does not calculate the hash > > > -\end{itemize} > > > - > > > -\label{itm:Device Types / Network Device / Device Operation = / > Control > > Virtqueue / Receive-side scaling (RSS) / RSS hash types/hash on= IPv6 > > packets without extension headers} > > > -The device calculates the hash on IPv6 packets without exten= sion > > > -headers according to the field \field{hash_types} of the > > virtio_net_rss_config structure as follows: > > > -\begin{itemize} > > > -\item If VIRTIO_NET_RSS_HASH_TYPE_TCPv6 is set and the packe= t has > > > -a TCPv6 header, the hash is calculated over the following fi= elds: > > > -\begin{itemize} > > > -\item Source IPv6 address > > > -\item Destination IPv6 address > > > -\item Source TCP port > > > -\item Destination TCP port > > > -\end{itemize} > > > -\item Else if VIRTIO_NET_RSS_HASH_TYPE_UDPv6 is set and the > > > -packet has a UDPv6 header, the hash is calculated over the > following > > fields: > > > -\begin{itemize} > > > -\item Source IPv6 address > > > -\item Destination IPv6 address > > > -\item Source UDP port > > > -\item Destination UDP port > > > -\end{itemize} > > > -\item Else if VIRTIO_NET_RSS_HASH_TYPE_IPv6 is set, the hash= is > > > -calculated over the following fields: > > > -\begin{itemize} > > > -\item Source IPv6 address > > > -\item Destination IPv6 address > > > -\end{itemize} > > > -\item Else the device does not calculate the hash > > > -\end{itemize} > > > - > > > -The device calculates the hash on IPv6 packets with extensio= n > > > -headers according to the field \field{hash_types} of the > > virtio_net_rss_config structure as follows: > > > -\begin{itemize} > > > -\item If VIRTIO_NET_RSS_HASH_TYPE_TCP_EX is set and the pack= et > > > -has a TCPv6 header, the hash is calculated over the followin= g > fields: > > > -\begin{itemize} > > > -\item Home address from the home address option in the IPv6 > destination > > options header. If the extension header is not present, use the > Source IPv6 > > address. > > > -\item IPv6 address that is contained in the Routing-Header-T= ype-2 > from > > the associated extension header. If the extension header is not > present, > > use the Destination IPv6 address. > > > -\item Source TCP port > > > -\item Destination TCP port > > > -\end{itemize} > > > -\item Else if VIRTIO_NET_RSS_HASH_TYPE_UDP_EX is set and the > > > -packet has a UDPv6 header, the hash is calculated over the > following > > fields: > > > -\begin{itemize} > > > -\item Home address from the home address option in the IPv6 > destination > > options header. If the extension header is not present, use the > Source IPv6 > > address. > > > -\item IPv6 address that is contained in the Routing-Header-T= ype-2 > from > > the associated extension header. If the extension header is not > present, > > use the Destination IPv6 address. > > > -\item Source UDP port > > > -\item Destination UDP port > > > -\end{itemize} > > > -\item Else if VIRTIO_NET_RSS_HASH_TYPE_IP_EX is set, the has= h is > > > -calculated over the following fields: > > > -\begin{itemize} > > > -\item Home address from the home address option in the IPv6 > destination > > options header. If the extension header is not present, use the > Source IPv6 > > address. > > > -\item IPv6 address that is contained in the Routing-Header-T= ype-2 > from > > the associated extension header. If the extension header is not > present, > > use the Destination IPv6 address. > > > -\end{itemize} > > > -\item Else skip IPv6 extension headers and calculate the has= h as > > > -defined for an IPv6 packet without extension headers (see \r= ef > > {itm:Device Types / Network Device / Device Operation / Control > Virtqueue / > > Receive-side scaling (RSS) / RSS hash types/hash on IPv6 packet= s > without > > extension headers}). > > > -\end{itemize} > > > +Fields \field{hash_key_length} and \field{hash_key_data} def= ine > the key > > to be used in hash calculation. > > > =20 > > > \drivernormative{\subparagraph}{Setting RSS parameters}{Devi= ce > Types / > > Network Device / Device Operation / Control Virtqueue / Receive= -side > > scaling (RSS) } > > > =20 > > > @@ -4093,12 +4204,12 @@ \subsubsection{Control Virtqueue}\lab= el > > {sec:Device Types / Network Device / Devi > > > =20 > > > A driver MUST use \field{indirection_table_mask} values that= are > less > > than \field{rss_max_indirection_table_length} reported by a dev= ice. > > > =20 > > > -A driver MUST NOT set any VIRTIO_NET_RSS_HASH_TYPE_ flags th= at are > not > > supported by a device. > > > +A driver MUST NOT set any VIRTIO_NET_HASH_TYPE_ flags that a= re not > > supported by a device. > > > =20 > > > \devicenormative{\subparagraph}{RSS processing}{Device Types= / > Network > > Device / Device Operation / Control Virtqueue / Receive-side sc= aling > (RSS) > > / RSS processing} > > > The device MUST determine the destination queue for a networ= k > packet as > > follows: > > > \begin{itemize} > > > -\item Calculate the hash of the packet as defined in \ref > {sec:Device > > Types / Network Device / Device Operation / Control Virtqueue / > > Receive-side scaling (RSS) / RSS hash types} > > > +\item Calculate the hash of the packet as defined in \ref > {sec:Device > > Types / Network Device / Device Operation / Processing of Incom= ing > Packets > > / Hash calculation for incoming packets}. > > > \item If the device did not calculate the hash for the speci= fic > packet, > > the device directs the packet to the receiveq specified by \fie= ld > > {unclassified_queue} of virtio_net_rss_config structure (value = of 0 > > corresponds to receiveq1). > > > \item Apply \field{indirection_table_mask} to the calculated= hash > and > > use the result as the index in the indirection table to get 0-b= ased > number > > of destination receiveq (value of 0 corresponds to receiveq1). > > > \end{itemize} > > > -- > > > 2.17.1 > > > > > > This publicly archived list offers a means to provide input to = the > > OASIS Virtual I/O Device (VIRTIO) TC. > > > > In order to verify user consent to the Feedback License terms a= nd > > to minimize spam in the list archive, subscription is required > > before posting. > > > > Subscribe: virtio-comment-subscribe@lists.oasis-open.org > > Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org > > List help: virtio-comment-help@lists.oasis-open.org > > List archive: https://lists.oasis-open.org/archives/virtio-comm= ent/ > > Feedback License: https://www.oasis-open.org/who/ipr/ > feedback_license.pdf > > List Guidelines: https://www.oasis-open.org/policies-guidelines= / > > mailing-lists > > Committee: https://www.oasis-open.org/committees/virtio/ > > Join OASIS: https://www.oasis-open.org/join/ > > > > > > >=20 >=20 >=20 This publicly archived list offers a means to provide input to the=0D OASIS Virtual I/O Device (VIRTIO) TC.=0D =0D In order to verify user consent to the Feedback License terms and=0D to minimize spam in the list archive, subscription is required=0D before posting.=0D =0D Subscribe: virtio-comment-subscribe@lists.oasis-open.org=0D Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org=0D List help: virtio-comment-help@lists.oasis-open.org=0D List archive: https://lists.oasis-open.org/archives/virtio-comment/=0D Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf= =0D List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lis= ts=0D Committee: https://www.oasis-open.org/committees/virtio/=0D Join OASIS: https://www.oasis-open.org/join/