[virtio-comment] [PATCH v5 0/1] Define VIRTIO_NET_F_HASH_REPORT feature

[virtio-comment] [PATCH v5 0/1] Define VIRTIO_NET_F_HASH_REPORT feature

[Yuri Benditovich]

Changes from v4:
Added padding_reserved field to the packet layout
Renamed hash_type field in the packet layout to hash_report

Changes from v3:
Rebased to latest master branch
Changes feature number to 57 (as 58 is under discussion)
Minor changes according to v3 review

Yuri Benditovich (1):
  virtio-net: Define per-packet hash reporting feature

 content.tex | 348 ++++++++++++++++++++++++++++++++++------------------
 1 file changed, 230 insertions(+), 118 deletions(-)

-- 
2.17.1


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[virtio-comment] [PATCH v5 1/1] virtio-net: Define per-packet hash reporting feature

[Yuri Benditovich]

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 | 348 ++++++++++++++++++++++++++++++++++------------------
 1 file changed, 230 insertions(+), 118 deletions(-)

diff --git a/content.tex b/content.tex
index b91a132..45ad5e9 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 +3180,9 @@ \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_report;       (Only if VIRTIO_NET_F_HASH_REPORT negotiated)
+        le16 padding_reserved;  (Only if VIRTIO_NET_F_HASH_REPORT negotiated)
 };
 \end{lstlisting}
 
@@ -3517,6 +3505,12 @@ \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 +3613,181 @@ \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_report} with the report type of calculated hash
+and \field{hash_value} with the value of calculated hash.
+
+If VIRTIO_NET_F_HASH_REPORT was negotiated but due to any reason the
+hash was not calculated, the device sets \field{hash_report} to VIRTIO_NET_HASH_REPORT_NONE.
+
+Possible values that the device can report in \field{hash_report} 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)
+
+\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 +4065,7 @@ \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 +4131,37 @@ \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 +4178,8 @@ \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 +4193,7 @@ \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 +4205,12 @@ \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


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[virtio-comment] Re: [PATCH v5 0/1] Define VIRTIO_NET_F_HASH_REPORT feature

[Yuri Benditovich]

If seems OK, please initiate the ballot

On Thu, Feb 20, 2020 at 8:47 AM Yuri Benditovich
<yuri.benditovich@daynix.com> wrote:
>
> Changes from v4:
> Added padding_reserved field to the packet layout
> Renamed hash_type field in the packet layout to hash_report
>
> Changes from v3:
> Rebased to latest master branch
> Changes feature number to 57 (as 58 is under discussion)
> Minor changes according to v3 review
>
> Yuri Benditovich (1):
>   virtio-net: Define per-packet hash reporting feature
>
>  content.tex | 348 ++++++++++++++++++++++++++++++++++------------------
>  1 file changed, 230 insertions(+), 118 deletions(-)
>
> --
> 2.17.1
>

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[virtio-comment] Re: [PATCH v5 0/1] Define VIRTIO_NET_F_HASH_REPORT feature

[Michael S. Tsirkin]

On Thu, Feb 27, 2020 at 11:49:50AM +0200, Yuri Benditovich wrote:
> If seems OK, please initiate the ballot

Sure. Please update the main description - it seems to be incomplete -
and include the final proposal link the in the main description -
it's in the comments now. Then let me know.

> On Thu, Feb 20, 2020 at 8:47 AM Yuri Benditovich
> <yuri.benditovich@daynix.com> wrote:
> >
> > Changes from v4:
> > Added padding_reserved field to the packet layout
> > Renamed hash_type field in the packet layout to hash_report
> >
> > Changes from v3:
> > Rebased to latest master branch
> > Changes feature number to 57 (as 58 is under discussion)
> > Minor changes according to v3 review
> >
> > Yuri Benditovich (1):
> >   virtio-net: Define per-packet hash reporting feature
> >
> >  content.tex | 348 ++++++++++++++++++++++++++++++++++------------------
> >  1 file changed, 230 insertions(+), 118 deletions(-)
> >
> > --
> > 2.17.1
> >


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