This series addresses a regression in ethtool flow steering where rules targeting the default RSS context (context 0) were incorrectly rejected.
The default RSS context always exists but is not stored in the rss_ctx xarray like additional contexts. The current validation logic was checking for the existence of context 0 in this array, causing valid flow steering rules to be rejected.
This prevented configurations such as: - High priority rules directing specific traffic to the default context - Low priority catch-all rules directing remaining traffic to additional contexts
Patch 1 fixes the validation logic to skip the existence check for context 0.
Patch 2 adds a selftest that verifies this behavior.
Changelog - v1->v2: https://lore.kernel.org/all/20250225071348.509432-1-gal@nvidia.com/ * Reworded commit message. * Added a selftest.
Gal Pressman (2): net: ethtool: Don't check if RSS context exists in case of context 0 selftests: drv-net: rss_ctx: Add test for ntuple rules targeting default RSS context
net/ethtool/ioctl.c | 3 +- .../selftests/drivers/net/hw/rss_ctx.py | 59 ++++++++++++++++++- 2 files changed, 60 insertions(+), 2 deletions(-)
Context 0 (default context) always exists, there is no need to check whether it exists or not when adding a flow steering rule.
The existing check fails when creating a flow steering rule for context 0 as it is not stored in the rss_ctx xarray.
For example: $ ethtool --config-ntuple eth2 flow-type tcp4 dst-ip 194.237.147.23 dst-port 19983 context 0 loc 618 rmgr: Cannot insert RX class rule: Invalid argument Cannot insert classification rule
An example usecase for this could be: - A high-priority rule (loc 0) directing specific port traffic to context 0. - A low-priority rule (loc 1) directing all other TCP traffic to context 1.
Fixes: de7f7582dff2 ("net: ethtool: prevent flow steering to RSS contexts which don't exist") Cc: Jakub Kicinski kuba@kernel.org Reviewed-by: Tariq Toukan tariqt@nvidia.com Reviewed-by: Nimrod Oren noren@nvidia.com Signed-off-by: Gal Pressman gal@nvidia.com Reviewed-by: Joe Damato jdamato@fastly.com --- net/ethtool/ioctl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c index 39ec920f5de7..71c828d0bf31 100644 --- a/net/ethtool/ioctl.c +++ b/net/ethtool/ioctl.c @@ -1083,7 +1083,8 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev, ethtool_get_flow_spec_ring(info.fs.ring_cookie)) return -EINVAL;
- if (!xa_load(&dev->ethtool->rss_ctx, info.rss_context)) + if (info.rss_context && + !xa_load(&dev->ethtool->rss_ctx, info.rss_context)) return -EINVAL; }
On 2025-06-09 at 12:02:49, Gal Pressman (gal@nvidia.com) wrote:
Context 0 (default context) always exists, there is no need to check whether it exists or not when adding a flow steering rule.
The existing check fails when creating a flow steering rule for context 0 as it is not stored in the rss_ctx xarray.
For example: $ ethtool --config-ntuple eth2 flow-type tcp4 dst-ip 194.237.147.23 dst-port 19983 context 0 loc 618 rmgr: Cannot insert RX class rule: Invalid argument Cannot insert classification rule
An example usecase for this could be:
- A high-priority rule (loc 0) directing specific port traffic to context 0.
- A low-priority rule (loc 1) directing all other TCP traffic to context
Fixes: de7f7582dff2 ("net: ethtool: prevent flow steering to RSS contexts which don't exist") Cc: Jakub Kicinski kuba@kernel.org Reviewed-by: Tariq Toukan tariqt@nvidia.com Reviewed-by: Nimrod Oren noren@nvidia.com Signed-off-by: Gal Pressman gal@nvidia.com Reviewed-by: Joe Damato jdamato@fastly.com
Reviewed-by: Subbaraya Sundeep sbhatta@marvell.com
Thanks, Sundeep
net/ethtool/ioctl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c index 39ec920f5de7..71c828d0bf31 100644 --- a/net/ethtool/ioctl.c +++ b/net/ethtool/ioctl.c @@ -1083,7 +1083,8 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev, ethtool_get_flow_spec_ring(info.fs.ring_cookie)) return -EINVAL;
if (!xa_load(&dev->ethtool->rss_ctx, info.rss_context))
if (info.rss_context &&
}!xa_load(&dev->ethtool->rss_ctx, info.rss_context)) return -EINVAL;
2.40.1
On Mon, 9 Jun 2025 15:02:49 +0300 Gal Pressman wrote:
Cc: Jakub Kicinski kuba@kernel.org Reviewed-by: Tariq Toukan tariqt@nvidia.com Reviewed-by: Nimrod Oren noren@nvidia.com Signed-off-by: Gal Pressman gal@nvidia.com Reviewed-by: Joe Damato jdamato@fastly.com
Did you receive a user report for this change in behavior?
On 10/06/2025 1:41, Jakub Kicinski wrote:
On Mon, 9 Jun 2025 15:02:49 +0300 Gal Pressman wrote:
Cc: Jakub Kicinski kuba@kernel.org Reviewed-by: Tariq Toukan tariqt@nvidia.com Reviewed-by: Nimrod Oren noren@nvidia.com Signed-off-by: Gal Pressman gal@nvidia.com Reviewed-by: Joe Damato jdamato@fastly.com
Did you receive a user report for this change in behavior?
No.
On Tue, 10 Jun 2025 08:58:52 +0300 Gal Pressman wrote:
On 10/06/2025 1:41, Jakub Kicinski wrote:
On Mon, 9 Jun 2025 15:02:49 +0300 Gal Pressman wrote:
Cc: Jakub Kicinski kuba@kernel.org Reviewed-by: Tariq Toukan tariqt@nvidia.com Reviewed-by: Nimrod Oren noren@nvidia.com Signed-off-by: Gal Pressman gal@nvidia.com Reviewed-by: Joe Damato jdamato@fastly.com
Did you receive a user report for this change in behavior?
No.
Please make this clear in the commit message.
Add test_rss_default_context_rule() to verify that ntuple rules can correctly direct traffic to the default RSS context (context 0).
The test creates two ntuple rules with explicit location priorities: - A high-priority rule (loc 0) directing specific port traffic to context 0. - A low-priority rule (loc 1) directing all other TCP traffic to context 1.
This validates that: 1. Rules targeting the default context function properly. 2. Traffic steering works as expected when mixing default and additional RSS contexts.
The test was written by AI, and reviewed by humans.
Cc: Jakub Kicinski kuba@kernel.org Reviewed-by: Nimrod Oren noren@nvidia.com Signed-off-by: Gal Pressman gal@nvidia.com --- .../selftests/drivers/net/hw/rss_ctx.py | 59 ++++++++++++++++++- 1 file changed, 58 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/drivers/net/hw/rss_ctx.py b/tools/testing/selftests/drivers/net/hw/rss_ctx.py index ca60ae325c22..6aef8f643ca4 100755 --- a/tools/testing/selftests/drivers/net/hw/rss_ctx.py +++ b/tools/testing/selftests/drivers/net/hw/rss_ctx.py @@ -747,6 +747,62 @@ def test_rss_ntuple_addition(cfg): 'noise' : (0,) })
+def test_rss_default_context_rule(cfg): + """ + Allocate a port, direct this port to context 0, then create a new RSS + context and steer all TCP traffic to it (context 1). Verify that: + * Traffic to the specific port continues to use queues of the main + context (0/1). + * Traffic to any other TCP port is redirected to the new context + (queues 2/3). + """ + + require_ntuple(cfg) + + queue_cnt = len(_get_rx_cnts(cfg)) + if queue_cnt < 4: + try: + ksft_pr(f"Increasing queue count {queue_cnt} -> 4") + ethtool(f"-L {cfg.ifname} combined 4") + defer(ethtool, f"-L {cfg.ifname} combined {queue_cnt}") + except: + raise KsftSkipEx("Not enough queues for the test") + + # Use queues 0 and 1 for the main context + ethtool(f"-X {cfg.ifname} equal 2") + defer(ethtool, f"-X {cfg.ifname} default") + + # Create a new RSS context that uses queues 2 and 3 + ctx_id = ethtool_create(cfg, "-X", "context new start 2 equal 2") + defer(ethtool, f"-X {cfg.ifname} context {ctx_id} delete") + + # Generic low-priority rule: redirect all TCP traffic to the new context. + # Give it an explicit higher location number (lower priority). + flow_generic = f"flow-type tcp{cfg.addr_ipver} dst-ip {cfg.addr} context {ctx_id} loc 1" + ethtool(f"-N {cfg.ifname} {flow_generic}") + defer(ethtool, f"-N {cfg.ifname} delete 1") + + # Specific high-priority rule for a random port that should stay on context 0. + # Assign loc 0 so it is evaluated before the generic rule. + port_main = rand_port() + flow_main = f"flow-type tcp{cfg.addr_ipver} dst-ip {cfg.addr} dst-port {port_main} context 0 loc 0" + ethtool(f"-N {cfg.ifname} {flow_main}") + defer(ethtool, f"-N {cfg.ifname} delete 0") + + _ntuple_rule_check(cfg, 1, ctx_id) + + # Verify that traffic matching the specific rule still goes to queues 0/1 + _send_traffic_check(cfg, port_main, "context 0", + { 'target': (0, 1), + 'empty' : (2, 3) }) + + # And that traffic for any other port is steered to the new context + port_other = rand_port() + _send_traffic_check(cfg, port_other, f"context {ctx_id}", + { 'target': (2, 3), + 'noise' : (0, 1) }) + + def main() -> None: with NetDrvEpEnv(__file__, nsim_test=False) as cfg: cfg.context_cnt = None @@ -760,7 +816,8 @@ def main() -> None: test_rss_context_overlap, test_rss_context_overlap2, test_rss_context_out_of_order, test_rss_context4_create_with_cfg, test_flow_add_context_missing, - test_delete_rss_context_busy, test_rss_ntuple_addition], + test_delete_rss_context_busy, test_rss_ntuple_addition, + test_rss_default_context_rule], args=(cfg, )) ksft_exit()
On Mon, 9 Jun 2025 15:02:50 +0300 Gal Pressman wrote:
The test was written by AI, and reviewed by humans.
Please use pylint and avoid adding new warnings:
tools/testing/selftests/drivers/net/hw/rss_ctx.py:788:0: C0301: Line too long (103/100) (line-too-long) tools/testing/selftests/drivers/net/hw/rss_ctx.py:769:12: W0707: Consider explicitly re-raising using 'except Exception as exc' and 'raise KsftSkipEx('Not enough queues for the test') from exc' (raise-missing-from)
On 11/06/2025 0:32, Jakub Kicinski wrote:
On Mon, 9 Jun 2025 15:02:50 +0300 Gal Pressman wrote:
The test was written by AI, and reviewed by humans.
Please use pylint and avoid adding new warnings:
Ack.
tools/testing/selftests/drivers/net/hw/rss_ctx.py:788:0: C0301: Line too long (103/100) (line-too-long)
Are you sure you want to blindly break this line? It's a single string.
tools/testing/selftests/drivers/net/hw/rss_ctx.py:769:12: W0707: Consider explicitly re-raising using 'except Exception as exc' and 'raise KsftSkipEx('Not enough queues for the test') from exc' (raise-missing-from)
Cool, didn't know python can do that.
On Wed, 11 Jun 2025 08:06:38 +0300 Gal Pressman wrote:
tools/testing/selftests/drivers/net/hw/rss_ctx.py:788:0: C0301: Line too long (103/100) (line-too-long)
Are you sure you want to blindly break this line? It's a single string.
Yeah, if it's a string leave it be. This one is just a check, the other one as a warning. Unhelpfully I don't see an option in pylint to add the bad lines to the report so its a bit hard to tell at a glance. The long strings and the lack of doc string in the main function are the two checks that we are definitely okay to ignore.
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