kernel/tools/testing/selftests/drivers/net/hw/ncdevmem.c, branch master

selftests: drv-net: add HDS payload sweep test for devmem TCP

2026-02-17T09:40:14Z

Add check_rx_hds test that verifies header/data split works across payload sizes. The test sweeps payload sizes from 1 byte to 8KB, if any data propagates up to userspace as SCM_DEVMEM_LINEAR, then the test fails. This shows that regardless of payload size, ncdevmem's configuration of hds-thresh to 0 is respected. Add -L (--fail-on-linear) flag to ncdevmem that causes the receiver to fail if any SCM_DEVMEM_LINEAR cmsg is received. Use socat option for fixed block sizing and tcp nodelay to disable nagle's algo to avoid buffering. Signed-off-by: Bobby Eshleman Link: https://patch.msgid.link/20260211-fbnic-tcp-hds-fixes-v1-4-55d050e6f606@meta.com Signed-off-by: Paolo Abeni

selftests: drv-net: fix missing include in ncdevmem

2026-01-21T02:26:26Z

Commit ca9d74eb5f6a ("uapi: add INT_MAX and INT_MIN constants") recently removed some includes of limits.h in uAPI headers. ncdevmem.c was depending on them: ncdevmem.c: In function ‘ethtool_add_flow’: ncdevmem.c:369:60: error: ‘INT_MAX’ undeclared (first use in this function) 369 | if (endptr == id_start || flow_id < 0 || flow_id > INT_MAX) | ^~~~~~~ ncdevmem.c:77:1: note: ‘INT_MAX’ is defined in header ‘’; did you forget to ‘#include ’? Reviewed-by: Mina Almasry Link: https://patch.msgid.link/20260120180319.1673271-1-kuba@kernel.org Signed-off-by: Jakub Kicinski

selftests: ncdevmem: remove sleep on rx

2025-09-16T01:14:48Z

RX devmem sometimes fails on NIPA: https://netdev-3.bots.linux.dev/vmksft-fbnic-qemu-dbg/results/294402/7-devmem-py/ Both RSS and flow steering are properly installed, but the wait_port_listen fails. Try to remove sleep(1) to see if the cause of the failure is spending too much time during RX setup. I don't see a good reason to have sleep in the first place. If there needs to be a delay between installing the rules and receiving the traffic, let's add it to the callers (devmem.py) instead. Signed-off-by: Stanislav Fomichev Reviewed-by: Mina Almasry Link: https://patch.msgid.link/20250912170611.676110-1-sdf@fomichev.me Signed-off-by: Jakub Kicinski

selftests: ncdevmem: don't retry EFAULT

2025-09-06T01:14:34Z

devmem test fails on NIPA. Most likely we get skb(s) with readable frags (why?) but the failure manifests as an OOM. The OOM happens because ncdevmem spams the following message: recvmsg ret=-1 recvmsg: Bad address As of today, ncdevmem can't deal with various reasons of EFAULT: - falling back to regular recvmsg for non-devmem skbs - increasing ctrl_data size (can't happen with ncdevmem's large buffer) Exit (cleanly) with error when recvmsg returns EFAULT. This should at least cause the test to cleanup its state. Signed-off-by: Stanislav Fomichev Reviewed-by: Mina Almasry Link: https://patch.msgid.link/20250904182710.1586473-1-sdf@fomichev.me Signed-off-by: Jakub Kicinski

selftests: drv-net: ncdevmem: explicitly set HDS threshold to 0

2025-08-27T00:35:28Z

Make sure we set HDS threshold to 0 if the device supports changing it. It's required for ZC. Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20250825180447.2252977-6-kuba@kernel.org Signed-off-by: Jakub Kicinski

selftests: drv-net: ncdevmem: restore original HDS setting before exiting

2025-08-27T00:35:28Z

Restore HDS settings if we modified them. Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20250825180447.2252977-5-kuba@kernel.org Signed-off-by: Jakub Kicinski

selftests: drv-net: ncdevmem: restore old channel config

2025-08-27T00:35:27Z

In case changing channel count with provider bound succeeds unexpectedly - make sure we return to original settings. Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20250825180447.2252977-4-kuba@kernel.org Signed-off-by: Jakub Kicinski

selftests: drv-net: ncdevmem: save IDs of flow rules we added

2025-08-27T00:35:27Z

In prep for more selective resetting of ntuple filters try to save the rule IDs to a table. Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20250825180447.2252977-3-kuba@kernel.org Signed-off-by: Jakub Kicinski

selftests: drv-net: ncdevmem: remove use of error()

2025-08-27T00:35:27Z

Using error() makes it impossible for callers to unwind their changes. Replace error() calls with proper error handling. Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20250825180447.2252977-2-kuba@kernel.org Signed-off-by: Jakub Kicinski

selftests: drv-net: ncdevmem: make configure_channels() support combined channels

2025-08-20T00:49:35Z

ncdevmem tests that the kernel correctly rejects attempts to deactivate queues with MPs bound. Make the configure_channels() test support combined channels. Currently it tries to set the queue counts to rx N tx N-1, which only makes sense for devices which have IRQs per ring type. Most modern devices used combined IRQs/channels with both Rx and Tx queues. Since the math is total Rx == combined+Rx setting Rx when combined is non-zero will be increasing the total queue count, not decreasing as the test intends. Note that the test would previously also try to set the Tx ring count to Rx - 1, for some reason. Which would be 0 if the device has only 2 queues configured. With this change (device with 2 queues): setting channel count rx:1 tx:1 YNL set channels: Kernel error: 'requested channel counts are too low for existing memory provider setting (2)' Reviewed-by: Mina Almasry Link: https://patch.msgid.link/20250815231513.381652-1-kuba@kernel.org Signed-off-by: Jakub Kicinski