netdev - [PATCH net-next 2/5] selftests: hw-net: toeplitz: make sure NICs have pure Toeplitz configured

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Message-ID: <20251121040259.3647749-3-kuba@kernel.org>
Date: Thu, 20 Nov 2025 20:02:56 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org,
	edumazet@...gle.com,
	pabeni@...hat.com,
	andrew+netdev@...n.ch,
	horms@...nel.org,
	willemb@...gle.com,
	petrm@...dia.com,
	dw@...idwei.uk,
	shuah@...nel.org,
	linux-kselftest@...r.kernel.org,
	Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH net-next 2/5] selftests: hw-net: toeplitz: make sure NICs have pure Toeplitz configured

Make sure that the NIC under test is configured for pure Toeplitz
hashing, and no input key transform (no symmetric hashing).

Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
 .../selftests/drivers/net/hw/toeplitz.py      | 29 ++++++++++++-------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/toeplitz.py b/tools/testing/selftests/drivers/net/hw/toeplitz.py
index 9019a8c1ff62..642a5cc385b6 100755
--- a/tools/testing/selftests/drivers/net/hw/toeplitz.py
+++ b/tools/testing/selftests/drivers/net/hw/toeplitz.py
@@ -17,6 +17,9 @@ from lib.py import cmd, bkg, rand_port, defer
 from lib.py import ksft_in
 from lib.py import ksft_variants, KsftNamedVariant, KsftSkipEx, KsftFailEx
 
+# "define" for the ID of the Toeplitz hash function
+ETH_RSS_HASH_TOP = 1
+
 
 def _check_rps_and_rfs_not_configured(cfg):
     """Verify that RPS is not already configured."""
@@ -34,16 +37,6 @@ from lib.py import ksft_variants, KsftNamedVariant, KsftSkipEx, KsftFailEx
             raise KsftSkipEx(f"RFS already configured {rfs_file}: {val}")
 
 
-def _get_rss_key(cfg):
-    """
-    Read the RSS key from the device.
-    Return a string in the traditional %02x:%02x:%02x:.. format.
-    """
-
-    rss = cfg.ethnl.rss_get({"header": {"dev-index": cfg.ifindex}})
-    return ':'.join(f'{b:02x}' for b in rss["hkey"])
-
-
 def _get_cpu_for_irq(irq):
     with open(f"/proc/irq/{irq}/smp_affinity_list", "r",
               encoding="utf-8") as fp:
@@ -153,8 +146,22 @@ from lib.py import ksft_variants, KsftNamedVariant, KsftSkipEx, KsftFailEx
     # Check that rxhash is enabled
     ksft_in("receive-hashing: on", cmd(f"ethtool -k {cfg.ifname}").stdout)
 
+    rss = cfg.ethnl.rss_get({"header": {"dev-index": cfg.ifindex}})
+    # Make sure NIC is configured to use Toeplitz hash, and no key xfrm.
+    if rss.get('hfunc') != ETH_RSS_HASH_TOP or rss.get('input-xfrm'):
+        cfg.ethnl.rss_set({"header": {"dev-index": cfg.ifindex},
+                           "hfunc": ETH_RSS_HASH_TOP,
+                           "input-xfrm": {}})
+        defer(cfg.ethnl.rss_set, {"header": {"dev-index": cfg.ifindex},
+                                  "hfunc": rss.get('hfunc'),
+                                  "input-xfrm": rss.get('input-xfrm', {})
+                                  })
+        # Refresh in case changing hfunc changes things.
+        rss = cfg.ethnl.rss_get({"header": {"dev-index": cfg.ifindex}})
+
+    key = ':'.join(f'{b:02x}' for b in rss["hkey"])
+
     port = rand_port(socket.SOCK_DGRAM)
-    key = _get_rss_key(cfg)
 
     toeplitz_path = cfg.test_dir / "toeplitz"
     rx_cmd = [
-- 
2.51.1