Merge branch 'selftests-net-page_poll-allocation-error-injection'

Jakub Kicinski says:

====================
selftests: net: page_poll allocation error injection

Add a test for exercising driver memory allocation failure paths.
page pool is a bit tricky to inject errors into at the page allocator
level because of the bulk alloc and recycling, so add explicit error
injection support "in front" of the caches.

Add a test to exercise that using only the standard APIs.
This is the first useful test for the new tests with an endpoint.
There's no point testing netdevsim here, so this is also the first
HW-only test in Python.

I'm not super happy with the traffic generation using iperf3,
my initial approach was to use mausezahn. But it turned out to be
5x slower in terms of PPS. Hopefully this is good enough for now.

v1: https://lore.kernel.org/all/20240426232400.624864-1-kuba@kernel.org/
====================

Link: https://lore.kernel.org/r/20240429144426.743476-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 50 insertions, 2 deletions

diff --git a/tools/testing/selftests/drivers/net/lib/py/__init__.py b/tools/testing/selftests/drivers/net/lib/py/__init__.py
index 4789c1a4282d..401e70f7f136 100644
--- a/tools/testing/selftests/drivers/net/lib/py/__init__.py
+++ b/tools/testing/selftests/drivers/net/lib/py/__init__.py
@@ -15,4 +15,5 @@ except ModuleNotFoundError as e:
     sys.exit(4)
 
 from .env import *
+from .load import *
 from .remote import Remote
diff --git a/tools/testing/selftests/drivers/net/lib/py/env.py b/tools/testing/selftests/drivers/net/lib/py/env.py
index e2ab637e56dc..5c8f695b2536 100644
--- a/tools/testing/selftests/drivers/net/lib/py/env.py
+++ b/tools/testing/selftests/drivers/net/lib/py/env.py
@@ -2,7 +2,7 @@
 
 import os
 from pathlib import Path
-from lib.py import KsftSkipEx
+from lib.py import KsftSkipEx, KsftXfailEx
 from lib.py import cmd, ip
 from lib.py import NetNS, NetdevSimDev
 from .remote import Remote
@@ -76,7 +76,7 @@ class NetDrvEpEnv:
     nsim_v4_pfx = "192.0.2."
     nsim_v6_pfx = "2001:db8::"
 
-    def __init__(self, src_path):
+    def __init__(self, src_path, nsim_test=None):
 
         self.env = _load_env_file(src_path)
 
@@ -88,7 +88,10 @@ class NetDrvEpEnv:
         self._ns_peer = None
 
         if "NETIF" in self.env:
+            if nsim_test is True:
+                raise KsftXfailEx("Test only works on netdevsim")
             self._check_env()
+
             self.dev = ip("link show dev " + self.env['NETIF'], json=True)[0]
 
             self.v4 = self.env.get("LOCAL_V4")
@@ -98,6 +101,9 @@ class NetDrvEpEnv:
             kind = self.env["REMOTE_TYPE"]
             args = self.env["REMOTE_ARGS"]
         else:
+            if nsim_test is False:
+                raise KsftXfailEx("Test does not work on netdevsim")
+
             self.create_local()
 
             self.dev = self._ns.nsims[0].dev
diff --git a/tools/testing/selftests/drivers/net/lib/py/load.py b/tools/testing/selftests/drivers/net/lib/py/load.py
new file mode 100644
index 000000000000..abdb677bdb1c
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/lib/py/load.py
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0
+
+import time
+
+from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen
+
+class GenerateTraffic:
+    def __init__(self, env):
+        env.require_cmd("iperf3", remote=True)
+
+        self.env = env
+
+        port = rand_port()
+        self._iperf_server = cmd(f"iperf3 -s -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",
+                                 background=True, host=env.remote)
+
+        # Wait for traffic to ramp up
+        pkt = ip("-s link show dev " + env.ifname, json=True)[0]["stats64"]["rx"]["packets"]
+        for _ in range(50):
+            time.sleep(0.1)
+            now = ip("-s link show dev " + env.ifname, json=True)[0]["stats64"]["rx"]["packets"]
+            if now - pkt > 1000:
+                return
+            pkt = now
+        self.stop(verbose=True)
+        raise Exception("iperf3 traffic did not ramp up")
+
+    def stop(self, verbose=None):
+        self._iperf_client.process(terminate=True)
+        if verbose:
+            ksft_pr(">> Client:")
+            ksft_pr(self._iperf_client.stdout)
+            ksft_pr(self._iperf_client.stderr)
+        self._iperf_server.process(terminate=True)
+        if verbose:
+            ksft_pr(">> Server:")
+            ksft_pr(self._iperf_server.stdout)
+            ksft_pr(self._iperf_server.stderr)