linux-next.git/tools/testing/selftests/drivers/net/hw/ncdevmem.c, branch master

selftests/net: ncdevmem: add -b option to set rx-page-size on bind

2026-08-08T01:32:39+00:00

Add -b to request a non-default niov size via NETDEV_A_DMABUF_RX_PAGE_SIZE. When the value exceeds PAGE_SIZE, udmabuf_alloc() switches to an MFD_HUGETLB-backed memfd so each 2 MB hugepage produces one naturally-aligned sg entry. Acked-by: Stanislav Fomichev Reviewed-by: Nikolay Aleksandrov Signed-off-by: Bobby Eshleman Link: https://patch.msgid.link/20260805-tcpdm-large-niovs-v8-2-3e0225e2808c@meta.com Signed-off-by: Jakub Kicinski

selftests: drv-net: ncdevmem: Open /dev/udmabuf O_RDONLY

2026-07-24T21:53:16+00:00

Write permissions on the /dev/udmabuf device file are not required to issue ioctls and allocate udmabufs. Applications should be opening this file as O_RDONLY. The BPF dmabuf_iter selftest already does this. [1] Users are pointing to these selftests as examples of how use udmabuf, and encountering permission errors on systems where write permissions are not available on /dev/udmabuf. Apply the principle of least privilege to selftests which use udmabuf by removing the write access mode from drivers/net/hw/ncdevmem.c. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c?h=v7.1#n49 Signed-off-by: T.J. Mercier Reviewed-by: Bobby Eshleman Link: https://patch.msgid.link/20260722205442.1894665-1-tjmercier@google.com Signed-off-by: Jakub Kicinski

selftests: drv-net: ncdevmem: add -n flag to skip NIC configuration

2026-05-19T01:49:07+00:00

Add a -n (skip_config) flag that causes ncdevmem to skip NIC configuration when operating as an RX server. When -n is passed, ncdevmem skips configuring header split, RSS, and flow steering, as well as their teardown on exit. This allows ksft tests to pre-configure the NIC in the host namespace before launching ncdevmem in the guest namespace. This is needed for netkit devmem tests where the test harness namespace has direct access to the NIC and the ncdevmem namespace does not. Acked-by: Stanislav Fomichev Signed-off-by: Bobby Eshleman Link: https://patch.msgid.link/20260514-tcp-dm-netkit-v5-4-408c59b91e66@meta.com Signed-off-by: Jakub Kicinski

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

2026-02-17T09:40:14+00:00

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

2026-01-21T02:26:26+00:00

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

2025-09-16T01:14:48+00:00

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

2025-09-06T01:14:34+00:00

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

2025-08-27T00:35:28+00:00

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

2025-08-27T00:35:28+00:00

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

2025-08-27T00:35:27+00:00

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