[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: Re: [virtio-comment] Re: [PATCH v4 1/1] virtio-net: Define per-packet hash reporting feature
On Wed, Feb 19, 2020 at 09:49:37AM -0500, Yuri Benditovich wrote: > > > âââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââ > > From: "Michael S. Tsirkin" <mst@redhat.com> > To: "Yuri Benditovich" <ybendito@redhat.com> > Cc: "Yuri Benditovich" <yuri.benditovich@daynix.com>, > 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 > > On Wed, Feb 19, 2020 at 06:07:13AM -0500, Yuri Benditovich wrote: > > > > > > > âââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââ > > > > From: "Michael S. Tsirkin" <mst@redhat.com> > > To: "Yuri Benditovich" <yuri.benditovich@daynix.com> > > 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 wrote: > > > 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 <yuri.benditovich@daynix.com> > > > --- > > > 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: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_REPORT(57)] Device can report per-packet > 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 length. > > > > > > @@ -2995,35 +2998,17 @@ \subsection{Device configuration layout}\ > label > > {sec:Device Types / Network Device > > > le32 supported_hash_types; > > > }; > > > \end{lstlisting} > > > -\label{sec:Device Types / Network Device / Device configuration > 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 bytes. > > > > > > -Field \field{rss_max_key_size} specifies the maximal supported > 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. > > > > > > -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. > > > > > > -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 headers > > > -\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 headers > > > -\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 Operation / > > Processing of Incoming Packets / Hash calculation for incoming > packets / > > Supported/enabled hash types} for details of supported hash types. > > > > > > \devicenormative{\subsubsection}{Device configuration layout} > {Device > > Types / Network Device / Device configuration layout} > > > > > > @@ -3048,7 +3033,7 @@ \subsection{Device configuration layout}\ > label > > {sec:Device Types / Network Device > > > negotiated. > > > > > > 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. > > > > > > 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} > > > > > > @@ -3517,6 +3504,12 @@ \subsubsection{Processing of Incoming > Packets}\ > > label{sec:Device Types / Network > > > > > > \end{enumerate} > > > > > > +If applicable, the device calculates per-packet hash for incoming > > 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 incoming > 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 Incoming > Packets} > > > \label{devicenormative:Device Types / Network Device / Device > Operation > > / Processing of Packets}%old label for latexdiff > > > > > > @@ -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 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. > > > +\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_data} > 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_data} > 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 / Hash > > calculation}). > > > +\end{itemize} > > > + > > > +Note that if the device offers VIRTIO_NET_F_HASH_REPORT, even if > it > > supports only one pair of virtqueues, it MUST support > > > +at least one of commands of VIRTIO_NET_CTRL_MQ class to configure > > 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 / Hash > > 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 headers > > > +\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 headers > > > +\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 / IPv4 > 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 has > > > +a TCP header, the hash is calculated over the following fields: > > > +\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 following > > 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 / IPv6 > packets > > without extension header} > > > +The device calculates the hash on IPv6 packets without extension > > > +headers according to 'Enabled hash types' bitmask as follows: > > > +\begin{itemize} > > > +\item If VIRTIO_NET_HASH_TYPE_TCPv6 is set and the packet has > > > +a TCPv6 header, the hash is calculated over the following fields: > > > +\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 / IPv6 > packets > > with extension header} > > > +The device calculates the hash on IPv6 packets with extension > > > +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 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-Type-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-Type-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-Type-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 hash as > > > +defined for an IPv6 packet without extension headers > > > +(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} > > > + > > > +\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_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 reason > the > > > +hash was not calculated, the device sets \field{hash_type} to > > VIRTIO_NET_HASH_REPORT_NONE. > > > + > > > +Possible values that the device can report in \field{hash_type} > 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 = 1 << (VIRTIO_NET_HASH_REPORT_XXX - 1) > > > > > > So hash_type is the HASH_REPORT value then? That's quite confusing. > > 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/report > > 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) > > We can but it seems like a waste, does it not? padding can be used for > something later ... > > > Or if we stay with the values as they are now: > > values 0..9 - VIRTIO_NET_WHAT? > > I thought that's VIRTIO_NET_HASH_REPORT_XXX > > OK, this is exactly what is defined > > > > bits from 0 to 8 - VIRTIO_NET_WHAT? > > > and this one VIRTIO_NET_HASH_TYPE_XXX? > > OK, this is also exactly what is defined > Right I'm saying what's defined is fine, just call the fields consistently. > > > 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 > > > 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... > We can do that too but it's up to you really. So fixing the below you would say bit 0 curresponding to value 1, bit 1 corresponding to value 2 etc. No bit corresponds to value 0 ? > > and just say that bit numbers are from this table, with bit > 0 corresponding to the value 0, bit 1 to value 1 etc. > > > maybe that would have been easier on the eyes - I didn't try, > I'm not even sure. > > But what you have is correct enough, we can always try to > improve the wording later. > > > > > > > > > + > > > +\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 / Network > > Device / Device Operation / Control Virtqueue} > > > > > > 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 automatic > 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} > > > > > > If more than one multiqueue mode is negotiated, the resulting > device > > configuration is defined by the last command sent by the driver. > > > @@ -3961,10 +4130,37 @@ \subsubsection{Control Virtqueue}\label > > {sec:Device Types / Network Device / Devi > > > according to the native endian of the guest rather than > > > (necessarily when not using the legacy interface) little-endian. > > > > > > +\subparagraph{Hash calculation}\label{sec:Device Types / Network > Device > > / Device Operation / Control Virtqueue / Automatic receive steering > in > > multiqueue mode / Hash calculation} > > > +If VIRTIO_NET_F_HASH_REPORT was negotiated and the device uses > automatic > > receive steering, > > > +the device MUST support a command to configure hash calculation > > parameters. > > > + > > > +The driver provides parameters for hash calculation as follows: > > > + > > > +\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 structure, > > > +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} define > the key > > to be used in hash calculation. > > > + > > > \paragraph{Receive-side scaling (RSS)}\label{sec:Device Types / > Network > > Device / Device Operation / Control Virtqueue / Receive-side scaling > (RSS)} > > > A device offers the feature VIRTIO_NET_F_RSS if it supports RSS > receive > > steering with Toeplitz hash calculation and configurable parameters. > > > > > > -A driver queries RSS capabilities of the device by reading device > > configuration as defined in \ref{sec:Device Types / Network Device / > Device > > configuration layout / RSS} > > > +A driver queries RSS capabilities of the device by reading device > > configuration as defined in \ref{sec:Device Types / Network Device / > Device > > configuration layout} > > > > > > \subparagraph{Setting RSS parameters}\label{sec:Device Types / > Network > > Device / Device Operation / Control Virtqueue / Receive-side scaling > (RSS) > > / Setting RSS parameters} > > > > > > @@ -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}. > > > > > > 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}\label > {sec:Device > > Types / Network Device / Devi > > > > > > 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}). > > > > > > -\subparagraph{RSS hash types}\label{sec:Device Types / Network > Device / > > Device Operation / Control Virtqueue / Receive-side scaling (RSS) / > RSS > > hash types} > > > - > > > -The device calculates the hash on IPv4 packets 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_TCPv4 is set and the packet has > > > -a TCP header, the hash is calculated over the following fields: > > > -\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 following > > 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 extension > > > -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 packet has > > > -a TCPv6 header, the hash is calculated over the following fields: > > > -\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 extension > > > -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 packet > > > -has a TCPv6 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-Type-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-Type-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 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-Type-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 hash as > > > -defined for an IPv6 packet without extension headers (see \ref > > {itm:Device Types / Network Device / Device Operation / Control > Virtqueue / > > Receive-side scaling (RSS) / RSS hash types/hash on IPv6 packets > without > > extension headers}). > > > -\end{itemize} > > > +Fields \field{hash_key_length} and \field{hash_key_data} define > the key > > to be used in hash calculation. > > > > > > \drivernormative{\subparagraph}{Setting RSS parameters}{Device > Types / > > Network Device / Device Operation / Control Virtqueue / Receive-side > > scaling (RSS) } > > > > > > @@ -4093,12 +4204,12 @@ \subsubsection{Control Virtqueue}\label > > {sec:Device Types / Network Device / Devi > > > > > > A driver MUST use \field{indirection_table_mask} values that are > less > > than \field{rss_max_indirection_table_length} reported by a device. > > > > > > -A driver MUST NOT set any VIRTIO_NET_RSS_HASH_TYPE_ flags that are > not > > supported by a device. > > > +A driver MUST NOT set any VIRTIO_NET_HASH_TYPE_ flags that are not > > supported by a device. > > > > > > \devicenormative{\subparagraph}{RSS processing}{Device Types / > Network > > Device / Device Operation / Control Virtqueue / Receive-side scaling > (RSS) > > / RSS processing} > > > The device MUST determine the destination queue for a network > 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 Incoming > Packets > > / Hash calculation for incoming packets}. > > > \item If the device did not calculate the hash for the specific > packet, > > the device directs the packet to the receiveq specified by \field > > {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-based > 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 and > > 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-comment/ > > 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/ > > > > > > > > >
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]