[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 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
> bits from 0 to 8 - VIRTIO_NET_WHAT?
and this one VIRTIO_NET_HASH_TYPE_XXX?
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
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]