selftests: drv-net: rss_ctx: add tests for RSS configuration and contexts

Add tests focusing on indirection table configuration and
creating extra RSS contexts in drivers which support it.

  $ export NETIF=eth0 REMOTE_...
  $ ./drivers/net/hw/rss_ctx.py
  KTAP version 1
  1..8
  ok 1 rss_ctx.test_rss_key_indir
  ok 2 rss_ctx.test_rss_context
  ok 3 rss_ctx.test_rss_context4
  # Increasing queue count 44 -> 66
  # Failed to create context 32, trying to test what we got
  ok 4 rss_ctx.test_rss_context32 # SKIP Tested only 31 contexts, wanted 32
  ok 5 rss_ctx.test_rss_context_overlap
  ok 6 rss_ctx.test_rss_context_overlap2
  # .. sprays traffic like a headless chicken ..
  not ok 7 rss_ctx.test_rss_context_out_of_order
  ok 8 rss_ctx.test_rss_context4_create_with_cfg
  # Totals: pass:6 fail:1 xfail:0 xpass:0 skip:1 error:0

Note that rss_ctx.test_rss_context_out_of_order fails with the device
I tested with, but it seems to be a device / driver bug.
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240626012456.2326192-5-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/drivers/net/hw/Makefile

@@ -11,6 +11,7 @@ TEST_PROGS = \
 	hw_stats_l3_gre.sh \
 	loopback.sh \
 	pp_alloc_fail.py \
+	rss_ctx.py \
 	#
 
 TEST_FILES := \

tools/testing/selftests/drivers/net/lib/py/load.py

@@ -5,13 +5,14 @@ import time
 from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen
 
 class GenerateTraffic:
-    def __init__(self, env):
+    def __init__(self, env, port=None):
         env.require_cmd("iperf3", remote=True)
 
         self.env = env
 
-        port = rand_port()
-        self._iperf_server = cmd(f"iperf3 -s -p {port}", background=True)
+        if port is None:
+            port = rand_port()
+        self._iperf_server = cmd(f"iperf3 -s -1 -p {port}", background=True)
         wait_port_listen(port)
         time.sleep(0.1)
         self._iperf_client = cmd(f"iperf3 -c {env.addr} -P 16 -p {port} -t 86400",

tools/testing/selftests/net/lib/py/ksft.py

@@ -57,6 +57,11 @@ def ksft_ge(a, b, comment=""):
         _fail("Check failed", a, "<", b, comment)
 
 
+def ksft_lt(a, b, comment=""):
+    if a >= b:
+        _fail("Check failed", a, ">=", b, comment)
+
+
 class ksft_raises:
     def __init__(self, expected_type):
         self.exception = None

tools/testing/selftests/net/lib/py/utils.py

@@ -9,6 +9,10 @@ import subprocess
 import time
 
 
+class CmdExitFailure(Exception):
+    pass
+
+
 class cmd:
     def __init__(self, comm, shell=True, fail=True, ns=None, background=False, host=None, timeout=5):
         if ns:
@@ -43,8 +47,8 @@ class cmd:
         if self.proc.returncode != 0 and fail:
             if len(stderr) > 0 and stderr[-1] == "\n":
                 stderr = stderr[:-1]
-            raise Exception("Command failed: %s\nSTDOUT: %s\nSTDERR: %s" %
-                            (self.proc.args, stdout, stderr))
+            raise CmdExitFailure("Command failed: %s\nSTDOUT: %s\nSTDERR: %s" %
+                                 (self.proc.args, stdout, stderr))
 
 
 class bkg(cmd):