Merge branch 'net-ethtool-rss-add-notifications'

Jakub Kicinski says:

====================
net: ethtool: rss: add notifications

Next step on the path to moving RSS config to Netlink. With the
refactoring of the driver-facing API for ETHTOOL_GRXFH/ETHTOOL_SRXFH
out of the way we can move on to more interesting work.

Add Netlink notifications for changes in RSS configuration.

As a reminder (part) of rss-get was introduced in previous releases
when input-xfrm (symmetric hashing) was added. rss-set isn't
implemented, yet, but we can implement rss-ntf and hook it into
the changes done via the IOCTL path (same as other ethtool-nl
notifications do).

Most of the series is concerned with passing arguments to notifications.
So far none of the notifications needed to be parametrized, but RSS can
have multiple contexts per device, and since GET operates on a single
context at a time, the notification needs to also be scoped to a context.
Patches 2-5 add support for passing arguments to notifications thru
ethtool-nl generic infra.

The notification handling itself is pretty trivial, it's mostly
hooking in the right entries into the ethool-nl op tables.

v1: https://lore.kernel.org/20250621171944.2619249-1-kuba@kernel.org
====================

Link: https://patch.msgid.link/20250623231720.3124717-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 89 insertions, 0 deletions

diff --git a/tools/testing/selftests/drivers/net/hw/rss_api.py b/tools/testing/selftests/drivers/net/hw/rss_api.py
new file mode 100755
index 000000000000..db0f723a674b
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/rss_api.py
@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+API level tests for RSS (mostly Netlink vs IOCTL).
+"""
+
+import glob
+from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_is, ksft_ne
+from lib.py import KsftSkipEx, KsftFailEx
+from lib.py import defer, ethtool
+from lib.py import EthtoolFamily
+from lib.py import NetDrvEnv
+
+
+def _ethtool_create(cfg, act, opts):
+    output = ethtool(f"{act} {cfg.ifname} {opts}").stdout
+    # Output will be something like: "New RSS context is 1" or
+    # "Added rule with ID 7", we want the integer from the end
+    return int(output.split()[-1])
+
+
+def test_rxfh_indir_ntf(cfg):
+    """
+    Check that Netlink notifications are generated when RSS indirection
+    table was modified.
+    """
+
+    qcnt = len(glob.glob(f"/sys/class/net/{cfg.ifname}/queues/rx-*"))
+    if qcnt < 2:
+        raise KsftSkipEx(f"Local has only {qcnt} queues")
+
+    ethnl = EthtoolFamily()
+    ethnl.ntf_subscribe("monitor")
+
+    ethtool(f"--disable-netlink -X {cfg.ifname} weight 0 1")
+    reset = defer(ethtool, f"-X {cfg.ifname} default")
+
+    ntf = next(ethnl.poll_ntf(duration=0.2), None)
+    if ntf is None:
+        raise KsftFailEx("No notification received")
+    ksft_eq(ntf["name"], "rss-ntf")
+    ksft_eq(set(ntf["msg"]["indir"]), {1})
+
+    reset.exec()
+    ntf = next(ethnl.poll_ntf(duration=0.2), None)
+    if ntf is None:
+        raise KsftFailEx("No notification received after reset")
+    ksft_eq(ntf["name"], "rss-ntf")
+    ksft_is(ntf["msg"].get("context"), None)
+    ksft_ne(set(ntf["msg"]["indir"]), {1})
+
+
+def test_rxfh_indir_ctx_ntf(cfg):
+    """
+    Check that Netlink notifications are generated when RSS indirection
+    table was modified on an additional RSS context.
+    """
+
+    qcnt = len(glob.glob(f"/sys/class/net/{cfg.ifname}/queues/rx-*"))
+    if qcnt < 2:
+        raise KsftSkipEx(f"Local has only {qcnt} queues")
+
+    ctx_id = _ethtool_create(cfg, "-X", "context new")
+    defer(ethtool, f"-X {cfg.ifname} context {ctx_id} delete")
+
+    ethnl = EthtoolFamily()
+    ethnl.ntf_subscribe("monitor")
+
+    ethtool(f"--disable-netlink -X {cfg.ifname} context {ctx_id} weight 0 1")
+
+    ntf = next(ethnl.poll_ntf(duration=0.2), None)
+    if ntf is None:
+        raise KsftFailEx("No notification received")
+    ksft_eq(ntf["name"], "rss-ntf")
+    ksft_eq(ntf["msg"].get("context"), ctx_id)
+    ksft_eq(set(ntf["msg"]["indir"]), {1})
+
+
+def main() -> None:
+    """ Ksft boiler plate main """
+
+    with NetDrvEnv(__file__, nsim_test=False) as cfg:
+        ksft_run(globs=globals(), case_pfx={"test_"}, args=(cfg, ))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()