[PATCH net-next v8 3/3] selftests/net: devmem.py: add check_rx_large_niov

[Bobby Eshleman]

From: Bobby Eshleman <bobbyeshleman@xxxxxxxx>

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

Silence pylint invalid-name (`with open() as f`) and too-many-arguments
(ncdevmem_rx grew to 6 args) at file scope.

Acked-by: Stanislav Fomichev <sdf@xxxxxxxxxxx>
Reviewed-by: Nikolay Aleksandrov <razor@xxxxxxxxxxxxx>
Signed-off-by: Bobby Eshleman <bobbyeshleman@xxxxxxxx>
---
 tools/testing/selftests/drivers/net/hw/devmem.py   |  11 ++-
 .../testing/selftests/drivers/net/hw/devmem_lib.py | 109 +++++++++++++++++++--
 .../testing/selftests/drivers/net/hw/nk_devmem.py  |  10 +-
 3 files changed, 119 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/devmem.py b/tools/testing/selftests/drivers/net/hw/devmem.py
index 031cf9905f65..82c11ffc4add 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 +31,17 @@ def check_rx_hds(cfg) -> None:
     run_rx_hds(cfg)
 
 
+def check_rx_large_niov(cfg) -> None:
+    """Run the devmem RX test with rx-page-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..209ce3b041e5 100644
--- a/tools/testing/selftests/drivers/net/hw/devmem_lib.py
+++ b/tools/testing/selftests/drivers/net/hw/devmem_lib.py
@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
+# pylint: disable=invalid-name,too-many-arguments
 """Shared helpers for devmem TCP selftests."""
 
+import os
 import re
 
 from lib.py import (bkg, cmd, defer, ethtool, rand_port, wait_port_listen,
@@ -8,19 +10,82 @@ from lib.py import (bkg, cmd, defer, ethtool, rand_port, wait_port_listen,
                     NetdevFamily)
 
 
-def require_devmem(cfg):
+RX_PAGE_SIZE_DEFAULT = 0
+RX_PAGE_SIZE_16K = 16384
+
+PROBE_RX_PAGE_SIZES = (RX_PAGE_SIZE_DEFAULT, RX_PAGE_SIZE_16K)
+
+NR_HUGEPAGES_FILE = "/proc/sys/vm/nr_hugepages"
+
+
+def _is_aligned(value, alignment):
+    """Equivalent of the kernel IS_ALIGNED(value, alignment).
+
+    alignment must be a power of two.
+    """
+    return (value & (alignment - 1)) == 0
+
+
+def _restore_nr_hugepages(nr_hugepages):
+    with open(NR_HUGEPAGES_FILE, 'w', encoding='utf-8') as f:
+        f.write(str(nr_hugepages))
+
+
+def _reserve_hugepages(want=64):
+    """Raise nr_hugepages to @want and arrange for it to be restored."""
+    with open(NR_HUGEPAGES_FILE, 'r+', encoding='utf-8') as f:
+        nr_hugepages = int(f.read().strip())
+        if nr_hugepages >= want:
+            return
+        f.seek(0)
+        f.write(str(want))
+    defer(_restore_nr_hugepages, nr_hugepages)
+
+
+def _probe_devmem(cfg, rx_page_size):
+    """Return True if ncdevmem can bind cfg.ifname at @rx_page_size."""
+    probe_command = f"{cfg.bin_local} -f {cfg.ifname}"
+    if rx_page_size != RX_PAGE_SIZE_DEFAULT:
+        probe_command += f" -b {rx_page_size}"
+    return cmd(probe_command, fail=False, shell=True).ret == 0
+
+
+def require_devmem(cfg, rx_page_size=RX_PAGE_SIZE_DEFAULT):
     """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}"
-        cfg.devmem_supported = cmd(probe_command, fail=False, shell=True).ret == 0
-        cfg.devmem_probed = True
+    if rx_page_size not in PROBE_RX_PAGE_SIZES:
+        raise RuntimeError(
+            f"rx-page-size={rx_page_size} is missing from "
+            f"PROBE_RX_PAGE_SIZES, so it was never probed.")
 
-    if not cfg.devmem_supported:
+    if not hasattr(cfg, "devmem_supported"):
+        _reserve_hugepages()
+        # Probe every size upfront: in nk tests a leased queue may land in
+        # ncdevmem's queue range and cause the probe to fail.
+        cfg.devmem_supported = {size: _probe_devmem(cfg, size)
+                                for size in PROBE_RX_PAGE_SIZES}
+
+    if not cfg.devmem_supported[RX_PAGE_SIZE_DEFAULT]:
         raise KsftSkipEx("Test requires devmem support")
 
+    if rx_page_size != RX_PAGE_SIZE_DEFAULT:
+        page_size = os.sysconf("SC_PAGE_SIZE")
+        if not _is_aligned(rx_page_size, page_size):
+            raise KsftSkipEx(
+                f"rx-page-size={rx_page_size} is invalid for this platform "
+                f"(must be a multiple of PAGE_SIZE={page_size})")
+
+        if not cfg.devmem_supported[rx_page_size]:
+            raise KsftSkipEx(
+                f"Test requires devmem rx-page-size={rx_page_size} support")
+
 
 def configure_nic(cfg):
     """Channels, rings, RSS, queue lease for netkit devmem."""
+    if not hasattr(cfg, "devmem_supported"):
+        raise RuntimeError(
+            "require_devmem() must be called before configure_nic(), which "
+            "may lease a queue away and make later probes fail.")
+
     if not hasattr(cfg, 'netns'):
         return
 
@@ -76,7 +141,8 @@ 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_page_size=RX_PAGE_SIZE_DEFAULT):
     """Build the ncdevmem RX listener command."""
     if hasattr(cfg, 'netns'):
         flow_rule_id = set_flow_rule(cfg, port)
@@ -96,6 +162,8 @@ 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_page_size != RX_PAGE_SIZE_DEFAULT:
+        extras.append(f"-b {rx_page_size}")
 
     parts = [cfg.bin_local, "-l", f"-f {ifname}", f"-s {addr}",
              f"-p {port}", *extras]
@@ -202,6 +270,33 @@ 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-page-size > PAGE_SIZE).
+
+    Sweep payload sizes that straddle the niov boundary: below, equal to,
+    and above rx_page_size, to exercise sub-niov, exact-niov, and multi-niov
+    RX paths.
+    """
+    require_devmem(cfg, rx_page_size=RX_PAGE_SIZE_16K)
+    _reserve_hugepages()
+    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_page_size=RX_PAGE_SIZE_16K)
+        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..61c6f31f01e5 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 +32,11 @@ def check_nk_rx_hds(cfg) -> None:
     run_rx_hds(cfg)
 
 
+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 +44,7 @@ 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