Document that the 'len' field in ethtool_gstrings and 'n_stats' field in
ethtool_stats optionally serve dual purposes: on entry they specify the
number of items requested, and on return they indicate the number
actually returned (which is not necessarily the same).
Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Link: https://patch.msgid.link/20260115060544.481550-1-gal@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Some modern NICs support including the IPv6 Flow Label in
the flow hash for RSS queue selection. This is outside
the old "Microsoft spec", but was included in the OCP NIC spec:
[ ] RSS include flow label in the hash (configurable)
https://www.opencompute.org/w/index.php?title=Core_Offloads#Receive_Side_Scaling
RSS Flow Label hashing allows TCP Protective Load Balancing (PLB)
to recover from receiver congestion / overload.
Rx CPU/queue hotspots are relatively common for data ingest
workloads, and so far we had to try to detect the condition
at the RPC layer and reopen the connection. PLB lets us change
the Flow Label and therefore Rx CPU on RTO, with minimal packet
reordering. PLB reaction times are much faster, and can happen
at any point in the connection, not just at RPC boundaries.
Due to the nature of host processing (relatively long queues,
other kernel subsystems masking IRQs for 100s of msecs)
the risk of reordering within the host is higher than in
the network. But for applications which need it - it is far
preferable to potentially persistent overload of subset of
queues.
It is expected that the hash communicated to the host
may change if the Flow Label changes. This may be surprising
to some host software, but I don't expect the devices
can compute two Toeplitz hashes, one with the Flow Label
for queue selection and one without for the rx hash
communicated to the host. Besides, changing the hash
may potentially help to change the path thru host queues.
User can disable NETIF_F_RXHASH if they require a stable
flow hash.
The name RXH_IP6_FL was chosen based on what we call
Flow Label variables in IPv6 processing (fl). I prefer
fl_lbl but that appears to be an fbnic-only spelling.
We could spell out RXH_IP6_FLOW_LABEL but existing
RXH_ defines are a lot more terse.
Willem notes [1] that Flow Label is defined as identifying the flow
and therefore including both the flow label _and_ the L4 header
fields is not generally necessary. But it should not hurt so
it's not explicitly prevented if the driver supports hashing
on both at the same time.
Link: https://lore.kernel.org/68483433b45e2_3cd66f29440@willemb.c.googlers.com.notmuch [1]
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20250811234212.580748-2-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Looks like some drivers (ena, enetc, fbnic.. there's probably more)
consider ETHER_FLOW to be legitimate target for flow hashing.
I'm not sure how intentional that is from the uAPI perspective
vs just an effect of ethtool IOCTL doing minimal input validation.
But Netlink will do strict validation, so we need to decide whether
we allow this use case or not. I don't see a strong reason against
it, and rejecting it would potentially regress a number of drivers.
So update the comments and flow_type_hashable().
Link: https://patch.msgid.link/20250708220640.2738464-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Symmetric RSS hash requires that:
* No other fields besides IP src/dst and/or L4 src/dst are set
* If src is set, dst must also be set
This restriction was only enforced when RXNFC was configured after
symmetric hash was enabled. In the opposite order of operations (RXNFC
then symmetric enablement) the check was not performed.
Perform the sanity check on set_rxfh as well, by iterating over all flow
types hash fields and making sure they are all symmetric.
Introduce a function that returns whether a flow type is hashable (not
spec only) and needs to be iterated over. To make sure that no one
forgets to update the list of hashable flow types when adding new flow
types, a static assert is added to draw the developer's attention.
The conversion of uapi #defines to enum is not ideal, but as Jakub
mentioned [1], we have precedent for that.
[1] https://lore.kernel.org/netdev/20250324073509.6571ade3@kernel.org/
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250508103034.885536-1-gal@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Fix the netlink type for hardware timestamp flags, which are represented
as a bitset of flags. Although only one flag is supported currently, the
correct netlink bitset type should be used instead of u32 to keep
consistency with other fields. Address this by adding a new named string
set description for the hwtstamp flag structure.
The code has been introduced in the current release so the uAPI change is
still okay.
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Fixes: 6e9e2eed4f ("net: ethtool: Add support for tsconfig command to get/set hwtstamp config")
Link: https://patch.msgid.link/20250205110304.375086-1-kory.maincent@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Introduce a new way to report PHY statistics in a structured and
standardized format using the netlink API. This new method does not
replace the old driver-specific stats, which can still be accessed with
`ethtool -S <eth name>`. The structured stats are available with
`ethtool -S <eth name> --all-groups`.
This new method makes it easier to diagnose problems by organizing stats
in a consistent and documented way.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
struct ethtool_link_settings tends to be used as a header for other
structures that have trailing bytes[1], but has a trailing flexible array
itself. Using this overlapped with other structures leads to ambiguous
object sizing in the compiler, so we want to avoid such situations (which
have caused real bugs in the past). Detecting this can be done with
-Wflex-array-member-not-at-end, which will need to be enabled globally.
Using a tagged struct_group() to create a new ethtool_link_settings_hdr
structure isn't possible as it seems we cannot use the tagged variant of
struct_group() due to syntax issues from C++'s perspective (even within
"extern C")[2]. Instead, we can just leave the offending member defined
in UAPI and remove it from the kernel's view of the structure, as Linux
doesn't actually use this member at all. There is also no change in
size since it was already a flexible array that didn't contribute to
size returned by any use of sizeof().
Reported-by: Jakub Kicinski <kuba@kernel.org>
Closes: https://lore.kernel.org/lkml/20241109100213.262a2fa0@kernel.org/ [2]
Link: https://lore.kernel.org/lkml/0bc2809fe2a6c11dd4c8a9a10d9bd65cccdb559b.1730238285.git.gustavoars@kernel.org/ [1]
Signed-off-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20241115204308.3821419-3-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use the `__struct_group()` helper to create a new tagged
`struct ethtool_link_settings_hdr`. This structure groups together
all the members of the flexible `struct ethtool_link_settings`
except the flexible array. As a result, the array is effectively
separated from the rest of the members without modifying the memory
layout of the flexible structure.
This new tagged struct will be used to fix problematic declarations
of middle-flex-arrays in composite structs[1].
[1] https://git.kernel.org/linus/d88cabfd9abc
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://patch.msgid.link/9e9fb0bd72e5ba1e916acbb4995b1e358b86a689.1730238285.git.gustavoars@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link topologies containing multiple network PHYs attached to the same
net_device can be found when using a PHY as a media converter for use
with an SFP connector, on which an SFP transceiver containing a PHY can
be used.
With the current model, the transceiver's PHY can't be used for
operations such as cable testing, timestamping, macsec offload, etc.
The reason being that most of the logic for these configuration, coming
from either ethtool netlink or ioctls tend to use netdev->phydev, which
in multi-phy systems will reference the PHY closest to the MAC.
Introduce a numbering scheme allowing to enumerate PHY devices that
belong to any netdev, which can in turn allow userspace to take more
precise decisions with regard to each PHY's configuration.
The numbering is maintained per-netdev, in a phy_device_list.
The numbering works similarly to a netdevice's ifindex, with
identifiers that are only recycled once INT_MAX has been reached.
This prevents races that could occur between PHY listing and SFP
transceiver removal/insertion.
The identifiers are assigned at phy_attach time, as the numbering
depends on the netdevice the phy is attached to. The PHY index can be
re-used for PHYs that are persistent.
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduce a new link mode necessary for 10 MBit single-pair
connection in BroadR-Reach mode on bcm5481x PHY by Broadcom.
This new link mode, 10baseT1BRR, is known as 1BR10 in the Broadcom
terminology. Another link mode to be used is 1BR100 and it is already
present as 100baseT1, because Broadcom's 1BR100 became 100baseT1
(IEEE 802.3bw).
Signed-off-by: Kamil Horák (2N) <kamilh@axis.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20240712150709.3134474-2-kamilh@axis.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
CMIS compliant modules such as QSFP-DD might be running a firmware that
can be updated in a vendor-neutral way by exchanging messages between
the host and the module as described in section 7.3.1 of revision 5.2 of
the CMIS standard.
Add a pair of new ethtool messages that allow:
* User space to trigger firmware update of transceiver modules
* The kernel to notify user space about the progress of the process
The user interface is designed to be asynchronous in order to avoid
RTNL being held for too long and to allow several modules to be
updated simultaneously. The interface is designed with CMIS compliant
modules in mind, but kept generic enough to accommodate future use
cases, if these arise.
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Link topologies containing multiple network PHYs attached to the same
net_device can be found when using a PHY as a media converter for use
with an SFP connector, on which an SFP transceiver containing a PHY can
be used.
With the current model, the transceiver's PHY can't be used for
operations such as cable testing, timestamping, macsec offload, etc.
The reason being that most of the logic for these configuration, coming
from either ethtool netlink or ioctls tend to use netdev->phydev, which
in multi-phy systems will reference the PHY closest to the MAC.
Introduce a numbering scheme allowing to enumerate PHY devices that
belong to any netdev, which can in turn allow userspace to take more
precise decisions with regard to each PHY's configuration.
The numbering is maintained per-netdev, in a phy_device_list.
The numbering works similarly to a netdevice's ifindex, with
identifiers that are only recycled once INT_MAX has been reached.
This prevents races that could occur between PHY listing and SFP
transceiver removal/insertion.
The identifiers are assigned at phy_attach time, as the numbering
depends on the netdevice the phy is attached to. The PHY index can be
re-used for PHYs that are persistent.
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
