[PATCH net-next 4/4] selftests/net: devmem.py: add check_rx_large_niov

[Bobby Eshleman <bobbyeshleman@gmail.com>]

From: Bobby Eshleman <bobbyeshleman@meta.com>

Add a new devmem test case for binding the dmabuf with rx-buf-size=16K.
The test sweeps RX payload sizes straddling the niov boundary to cover
the sub-niov, exact-niov, and multi-niov RX paths.

Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
 tools/testing/selftests/drivers/net/hw/devmem.py   | 12 +++++-
 .../testing/selftests/drivers/net/hw/devmem_lib.py | 46 +++++++++++++++++++++-
 .../testing/selftests/drivers/net/hw/nk_devmem.py  | 11 +++++-
 3 files changed, 63 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/devmem.py b/tools/testing/selftests/drivers/net/hw/devmem.py
index 031cf9905f65..47b54e18e7a6 100755
--- a/tools/testing/selftests/drivers/net/hw/devmem.py
+++ b/tools/testing/selftests/drivers/net/hw/devmem.py
@@ -2,7 +2,8 @@
 # SPDX-License-Identifier: GPL-2.0
 
 from os import path
-from devmem_lib import setup_test, run_rx, run_tx, run_tx_chunks, run_rx_hds
+from devmem_lib import (setup_test, run_rx, run_tx, run_tx_chunks, run_rx_hds,
+                        run_rx_large_niov)
 from lib.py import ksft_run, ksft_exit, ksft_disruptive
 from lib.py import NetDrvEpEnv
 
@@ -30,11 +31,18 @@ def check_rx_hds(cfg) -> None:
     run_rx_hds(cfg)
 
 
+@ksft_disruptive
+def check_rx_large_niov(cfg) -> None:
+    """Run the devmem RX test with rx-buf-size = 16 KiB."""
+    run_rx_large_niov(cfg)
+
+
 def main() -> None:
     """Run the devmem test cases."""
     with NetDrvEpEnv(__file__) as cfg:
         setup_test(cfg, path.abspath(path.dirname(__file__) + "/ncdevmem"))
-        ksft_run([check_rx, check_tx, check_tx_chunks, check_rx_hds],
+        ksft_run([check_rx, check_tx, check_tx_chunks, check_rx_hds,
+                  check_rx_large_niov],
                  args=(cfg,))
     ksft_exit()
 
diff --git a/tools/testing/selftests/drivers/net/hw/devmem_lib.py b/tools/testing/selftests/drivers/net/hw/devmem_lib.py
index 0921ff03eb81..1d9ad3a294c8 100644
--- a/tools/testing/selftests/drivers/net/hw/devmem_lib.py
+++ b/tools/testing/selftests/drivers/net/hw/devmem_lib.py
@@ -8,7 +8,7 @@ from lib.py import (bkg, cmd, defer, ethtool, rand_port, wait_port_listen,
                     NetdevFamily)
 
 
-def require_devmem(cfg):
+def require_devmem(cfg, rx_buf_size=0):
     """Probe ncdevmem on cfg.ifname and SKIP the test if devmem isn't supported."""
     if not hasattr(cfg, "devmem_probed"):
         probe_command = f"{cfg.bin_local} -f {cfg.ifname}"
@@ -18,6 +18,19 @@ def require_devmem(cfg):
     if not cfg.devmem_supported:
         raise KsftSkipEx("Test requires devmem support")
 
+    if rx_buf_size > 0:
+        if not hasattr(cfg, "devmem_rx_buf_size_probed"):
+            cfg.devmem_rx_buf_size_probed = {}
+
+        if rx_buf_size not in cfg.devmem_rx_buf_size_probed:
+            probe_command = f"{cfg.bin_local} -f {cfg.ifname} -b {rx_buf_size}"
+            cfg.devmem_rx_buf_size_probed[rx_buf_size] = \
+                cmd(probe_command, fail=False, shell=True).ret == 0
+
+        if not cfg.devmem_rx_buf_size_probed[rx_buf_size]:
+            raise KsftSkipEx(
+                f"Test requires devmem rx-buf-size={rx_buf_size} support")
+
 
 def configure_nic(cfg):
     """Channels, rings, RSS, queue lease for netkit devmem."""
@@ -76,7 +89,8 @@ def set_flow_rule(cfg, port):
     return int(re.search(r'ID (\d+)', output).group(1))
 
 
-def ncdevmem_rx(cfg, port, verify=True, fail_on_linear=False, flow_steer=False):
+def ncdevmem_rx(cfg, port, verify=True, fail_on_linear=False, flow_steer=False,
+                rx_buf_size=0):
     """Build the ncdevmem RX listener command."""
     if hasattr(cfg, 'netns'):
         flow_rule_id = set_flow_rule(cfg, port)
@@ -96,6 +110,8 @@ def ncdevmem_rx(cfg, port, verify=True, fail_on_linear=False, flow_steer=False):
         extras.append("-v 7")
     if fail_on_linear:
         extras.append("-L")
+    if rx_buf_size > 0:
+        extras.append(f"-b {rx_buf_size}")
 
     parts = [cfg.bin_local, "-l", f"-f {ifname}", f"-s {addr}",
              f"-p {port}", *extras]
@@ -202,6 +218,32 @@ def run_tx_chunks(cfg):
     ksft_eq(socat.stdout.strip(), "hello\nworld")
 
 
+def run_rx_large_niov(cfg):
+    """Run the devmem RX test with a large niov (rx-buf-size > PAGE_SIZE).
+
+    Sweep payload sizes that straddle the niov boundary: below, equal to,
+    and above rx_buf_size, to exercise sub-niov, exact-niov, and multi-niov
+    RX paths.
+    """
+    require_devmem(cfg, rx_buf_size=16384)
+    configure_nic(cfg)
+    netns = getattr(cfg, "netns", None)
+
+    for size in [1024, 4096, 8192, 16384, 32768, 65536]:
+        port = rand_port()
+        socat = socat_send(cfg, port)
+        listen_cmd = ncdevmem_rx(cfg, port,
+                                 flow_steer=not netns,
+                                 rx_buf_size=16384)
+        data_pipe = (f"yes $(echo -e \x01\x02\x03\x04\x05\x06) | "
+                     f"head -c {size} | {socat}")
+        with bkg(listen_cmd, exit_wait=True, ns=netns) as ncdevmem:
+            wait_port_listen(port, proto="tcp", ns=netns)
+            cmd(data_pipe, host=cfg.remote, shell=True)
+        ksft_eq(ncdevmem.ret, 0,
+                f"large-niov failed for payload size {size}")
+
+
 def run_rx_hds(cfg):
     """Run the HDS test by running devmem RX across a segment size sweep."""
     require_devmem(cfg)
diff --git a/tools/testing/selftests/drivers/net/hw/nk_devmem.py b/tools/testing/selftests/drivers/net/hw/nk_devmem.py
index 300ed2a70ab4..7f1867e4ff32 100755
--- a/tools/testing/selftests/drivers/net/hw/nk_devmem.py
+++ b/tools/testing/selftests/drivers/net/hw/nk_devmem.py
@@ -3,7 +3,8 @@
 """Test devmem TCP with netkit."""
 
 import os
-from devmem_lib import setup_test, run_rx, run_tx, run_tx_chunks, run_rx_hds
+from devmem_lib import (setup_test, run_rx, run_tx, run_tx_chunks, run_rx_hds,
+                        run_rx_large_niov)
 from lib.py import ksft_run, ksft_exit, ksft_disruptive
 from lib.py import NetDrvContEnv
 
@@ -31,6 +32,12 @@ def check_nk_rx_hds(cfg) -> None:
     run_rx_hds(cfg)
 
 
+@ksft_disruptive
+def check_nk_rx_large_niov(cfg) -> None:
+    """Run the devmem RX large-niov test through netkit."""
+    run_rx_large_niov(cfg)
+
+
 def main() -> None:
     """Run the netkit devmem test cases."""
     with NetDrvContEnv(__file__, rxqueues=2, primary_rx_redirect=True) as cfg:
@@ -38,7 +45,7 @@ def main() -> None:
                    os.path.join(os.path.dirname(os.path.abspath(__file__)),
                                 "ncdevmem"))
         ksft_run([check_nk_rx, check_nk_tx, check_nk_tx_chunks,
-                  check_nk_rx_hds], args=(cfg,))
+                  check_nk_rx_hds, check_nk_rx_large_niov], args=(cfg,))
     ksft_exit()
 
 

-- 
2.53.0-Meta