1 files changed, 313 insertions, 0 deletions
diff --git a/tools/testing/selftests/drivers/net/hw/rss_drv.py b/tools/testing/selftests/drivers/net/hw/rss_drv.py
new file mode 100755
index 000000000000..bd59dace6e15
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/rss_drv.py
@@ -0,0 +1,313 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Driver-related behavior tests for RSS.
+"""
+
+from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_ge
+from lib.py import ksft_variants, KsftNamedVariant, KsftSkipEx, ksft_raises
+from lib.py import defer, ethtool, CmdExitFailure
+from lib.py import EthtoolFamily, NlError
+from lib.py import NetDrvEnv
+
+
+def _is_power_of_two(n):
+    return n > 0 and (n & (n - 1)) == 0
+
+
+def _get_rss(cfg, context=0):
+    return ethtool(f"-x {cfg.ifname} context {context}", json=True)[0]
+
+
+def _test_rss_indir_size(cfg, qcnt, context=0):
+    """Test that indirection table size is at least 4x queue count."""
+    ethtool(f"-L {cfg.ifname} combined {qcnt}")
+
+    rss = _get_rss(cfg, context=context)
+    indir = rss['rss-indirection-table']
+    ksft_ge(len(indir), 4 * qcnt, "Table smaller than 4x")
+    return len(indir)
+
+
+def _maybe_create_context(cfg, create_context):
+    """ Either create a context and return its ID or return 0 for main ctx """
+    if not create_context:
+        return 0
+    try:
+        ctx = cfg.ethnl.rss_create_act({'header': {'dev-index': cfg.ifindex}})
+        ctx_id = ctx['context']
+        defer(cfg.ethnl.rss_delete_act,
+              {'header': {'dev-index': cfg.ifindex}, 'context': ctx_id})
+    except NlError:
+        raise KsftSkipEx("Device does not support additional RSS contexts")
+
+    return ctx_id
+
+
+def _require_dynamic_indir_size(cfg, ch_max):
+    """Skip if the device does not dynamically size its indirection table."""
+    ethtool(f"-X {cfg.ifname} default")
+    ethtool(f"-L {cfg.ifname} combined 2")
+    small = len(_get_rss(cfg)['rss-indirection-table'])
+    ethtool(f"-L {cfg.ifname} combined {ch_max}")
+    large = len(_get_rss(cfg)['rss-indirection-table'])
+
+    if small == large:
+        raise KsftSkipEx("Device does not dynamically size indirection table")
+
+
+@ksft_variants([
+    KsftNamedVariant("main", False),
+    KsftNamedVariant("ctx", True),
+])
+def indir_size_4x(cfg, create_context):
+    """
+    Test that the indirection table has at least 4 entries per queue.
+    Empirically network-heavy workloads like memcache suffer with the 33%
+    imbalance of a 2x indirection table size.
+    4x table translates to a 16% imbalance.
+    """
+    channels = cfg.ethnl.channels_get({'header': {'dev-index': cfg.ifindex}})
+    ch_max = channels.get('combined-max', 0)
+    qcnt = channels['combined-count']
+
+    if ch_max < 3:
+        raise KsftSkipEx(f"Not enough queues for the test: max={ch_max}")
+
+    defer(ethtool, f"-L {cfg.ifname} combined {qcnt}")
+    ethtool(f"-L {cfg.ifname} combined 3")
+
+    ctx_id = _maybe_create_context(cfg, create_context)
+
+    indir_sz = _test_rss_indir_size(cfg, 3, context=ctx_id)
+
+    # Test with max queue count (max - 1 if max is a power of two)
+    test_max = ch_max - 1 if _is_power_of_two(ch_max) else ch_max
+    if test_max > 3 and indir_sz < test_max * 4:
+        _test_rss_indir_size(cfg, test_max, context=ctx_id)
+
+
+@ksft_variants([
+    KsftNamedVariant("main", False),
+    KsftNamedVariant("ctx", True),
+])
+def resize_periodic(cfg, create_context):
+    """Test that a periodic indirection table survives channel changes.
+
+    Set a non-default periodic table ([3, 2, 1, 0] x N) via netlink,
+    reduce channels to trigger a fold, then increase to trigger an
+    unfold. Using a reversed pattern (instead of [0, 1, 2, 3]) ensures
+    the test can distinguish a correct fold from a driver that silently
+    resets the table to defaults. Verify the exact pattern is preserved
+    and the size tracks the channel count.
+    """
+    channels = cfg.ethnl.channels_get({'header': {'dev-index': cfg.ifindex}})
+    ch_max = channels.get('combined-max', 0)
+    qcnt = channels['combined-count']
+
+    if ch_max < 4:
+        raise KsftSkipEx(f"Not enough queues for the test: max={ch_max}")
+
+    defer(ethtool, f"-L {cfg.ifname} combined {qcnt}")
+
+    _require_dynamic_indir_size(cfg, ch_max)
+
+    ctx_id = _maybe_create_context(cfg, create_context)
+
+    # Set a non-default periodic pattern via netlink.
+    # Send only 4 entries (user_size=4) so the kernel replicates it
+    # to fill the device table. This allows folding down to 4 entries.
+    rss = _get_rss(cfg, context=ctx_id)
+    orig_size = len(rss['rss-indirection-table'])
+    pattern = [3, 2, 1, 0]
+    req = {'header': {'dev-index': cfg.ifindex}, 'indir': pattern}
+    if ctx_id:
+        req['context'] = ctx_id
+    else:
+        defer(ethtool, f"-X {cfg.ifname} default")
+    cfg.ethnl.rss_set(req)
+
+    # Shrink — should fold
+    ethtool(f"-L {cfg.ifname} combined 4")
+    rss = _get_rss(cfg, context=ctx_id)
+    indir = rss['rss-indirection-table']
+
+    ksft_ge(orig_size, len(indir), "Table did not shrink")
+    ksft_eq(indir, [3, 2, 1, 0] * (len(indir) // 4),
+            "Folded table has wrong pattern")
+
+    # Grow back — should unfold
+    ethtool(f"-L {cfg.ifname} combined {ch_max}")
+    rss = _get_rss(cfg, context=ctx_id)
+    indir = rss['rss-indirection-table']
+
+    ksft_eq(len(indir), orig_size, "Table size not restored")
+    ksft_eq(indir, [3, 2, 1, 0] * (len(indir) // 4),
+            "Unfolded table has wrong pattern")
+
+
+@ksft_variants([
+    KsftNamedVariant("main", False),
+    KsftNamedVariant("ctx", True),
+])
+def resize_below_user_size_reject(cfg, create_context):
+    """Test that shrinking below user_size is rejected.
+
+    Send a table via netlink whose size (user_size) sits between
+    the small and large device table sizes. The table is periodic,
+    so folding would normally succeed, but the user_size floor must
+    prevent it.
+    """
+    channels = cfg.ethnl.channels_get({'header': {'dev-index': cfg.ifindex}})
+    ch_max = channels.get('combined-max', 0)
+    qcnt = channels['combined-count']
+
+    if ch_max < 4:
+        raise KsftSkipEx(f"Not enough queues for the test: max={ch_max}")
+
+    defer(ethtool, f"-L {cfg.ifname} combined {qcnt}")
+
+    _require_dynamic_indir_size(cfg, ch_max)
+
+    ctx_id = _maybe_create_context(cfg, create_context)
+
+    # Measure the table size at max channels
+    rss = _get_rss(cfg, context=ctx_id)
+    big_size = len(rss['rss-indirection-table'])
+
+    # Measure the table size at reduced channels
+    ethtool(f"-L {cfg.ifname} combined 4")
+    rss = _get_rss(cfg, context=ctx_id)
+    small_size = len(rss['rss-indirection-table'])
+    ethtool(f"-L {cfg.ifname} combined {ch_max}")
+
+    if small_size >= big_size:
+        raise KsftSkipEx("Table did not shrink at reduced channels")
+
+    # Find a user_size
+    user_size = None
+    for div in [2, 4]:
+        candidate = big_size // div
+        if candidate > small_size and big_size % candidate == 0:
+            user_size = candidate
+            break
+    if user_size is None:
+        raise KsftSkipEx("No suitable user_size between small and big table")
+
+    # Send a periodic sub-table of exactly user_size entries.
+    # Pattern safe for 4 channels.
+    pattern = [0, 1, 2, 3] * (user_size // 4)
+    if len(pattern) != user_size:
+        raise KsftSkipEx(f"user_size ({user_size}) not divisible by 4")
+    req = {'header': {'dev-index': cfg.ifindex}, 'indir': pattern}
+    if ctx_id:
+        req['context'] = ctx_id
+    else:
+        defer(ethtool, f"-X {cfg.ifname} default")
+    cfg.ethnl.rss_set(req)
+
+    # Shrink channels — table would go to small_size < user_size.
+    # The table is periodic so folding would work, but user_size
+    # floor must reject it.
+    with ksft_raises(CmdExitFailure):
+        ethtool(f"-L {cfg.ifname} combined 4")
+
+
+@ksft_variants([
+    KsftNamedVariant("main", False),
+    KsftNamedVariant("ctx", True),
+])
+def resize_nonperiodic_reject(cfg, create_context):
+    """Test that a non-periodic table blocks channel reduction.
+
+    Set equal weight across all queues so the table is not periodic
+    at any smaller size, then verify channel reduction is rejected.
+    An additional context with a periodic table is created to verify
+    that validation catches the non-periodic one even when others
+    are fine.
+    """
+    channels = cfg.ethnl.channels_get({'header': {'dev-index': cfg.ifindex}})
+    ch_max = channels.get('combined-max', 0)
+    qcnt = channels['combined-count']
+
+    if ch_max < 4:
+        raise KsftSkipEx(f"Not enough queues for the test: max={ch_max}")
+
+    defer(ethtool, f"-L {cfg.ifname} combined {qcnt}")
+
+    _require_dynamic_indir_size(cfg, ch_max)
+
+    ctx_id = _maybe_create_context(cfg, create_context)
+    ctx_ref = f"context {ctx_id}" if ctx_id else ""
+
+    # Create an extra context with a periodic (foldable) table so that
+    # the validation must iterate all contexts to find the bad one.
+    extra_ctx = _maybe_create_context(cfg, True)
+    ethtool(f"-X {cfg.ifname} context {extra_ctx} equal 2")
+
+    ethtool(f"-X {cfg.ifname} {ctx_ref} equal {ch_max}")
+    if not create_context:
+        defer(ethtool, f"-X {cfg.ifname} default")
+
+    with ksft_raises(CmdExitFailure):
+        ethtool(f"-L {cfg.ifname} combined 2")
+
+
+@ksft_variants([
+    KsftNamedVariant("main", False),
+    KsftNamedVariant("ctx", True),
+])
+def resize_nonperiodic_no_corruption(cfg, create_context):
+    """Test that a failed resize does not corrupt table or channel count.
+
+    Set a non-periodic table, attempt a channel reduction (which must
+    fail), then verify both the indirection table contents and the
+    channel count are unchanged.
+    """
+    channels = cfg.ethnl.channels_get({'header': {'dev-index': cfg.ifindex}})
+    ch_max = channels.get('combined-max', 0)
+    qcnt = channels['combined-count']
+
+    if ch_max < 4:
+        raise KsftSkipEx(f"Not enough queues for the test: max={ch_max}")
+
+    defer(ethtool, f"-L {cfg.ifname} combined {qcnt}")
+
+    _require_dynamic_indir_size(cfg, ch_max)
+
+    ctx_id = _maybe_create_context(cfg, create_context)
+    ctx_ref = f"context {ctx_id}" if ctx_id else ""
+
+    ethtool(f"-X {cfg.ifname} {ctx_ref} equal {ch_max}")
+    if not create_context:
+        defer(ethtool, f"-X {cfg.ifname} default")
+
+    rss_before = _get_rss(cfg, context=ctx_id)
+
+    with ksft_raises(CmdExitFailure):
+        ethtool(f"-L {cfg.ifname} combined 2")
+
+    rss_after = _get_rss(cfg, context=ctx_id)
+    ksft_eq(rss_after['rss-indirection-table'],
+            rss_before['rss-indirection-table'],
+            "Indirection table corrupted after failed resize")
+
+    channels = cfg.ethnl.channels_get({'header': {'dev-index': cfg.ifindex}})
+    ksft_eq(channels['combined-count'], ch_max,
+            "Channel count changed after failed resize")
+
+
+def main() -> None:
+    """ Ksft boiler plate main """
+    with NetDrvEnv(__file__) as cfg:
+        cfg.ethnl = EthtoolFamily()
+        ksft_run([indir_size_4x, resize_periodic,
+                  resize_below_user_size_reject,
+                  resize_nonperiodic_reject,
+                  resize_nonperiodic_no_corruption], args=(cfg, ))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()