Add attach/detach and XDP offload selftests for knod, exercising the genetlink control plane and the BPF data path over a knod-capable NIC.
Signed-off-by: Taehee Yoo <[email protected]> (cherry picked from commit 320315bfd9a324ab029c2fe9eee52997592e5d0c) --- .../selftests/drivers/net/knod/Makefile | 17 ++ .../testing/selftests/drivers/net/knod/config | 7 + .../selftests/drivers/net/knod/knod_attach.sh | 135 +++++++++++++ .../drivers/net/knod/knod_xdp_ktime.sh | 173 +++++++++++++++++ .../drivers/net/knod/knod_xdp_loop.sh | 129 +++++++++++++ .../testing/selftests/drivers/net/knod/lib.sh | 181 ++++++++++++++++++ .../drivers/net/knod/xdp_ktime.bpf.c | 32 ++++ .../selftests/drivers/net/knod/xdp_loop.bpf.c | 42 ++++ 8 files changed, 716 insertions(+) create mode 100644 tools/testing/selftests/drivers/net/knod/Makefile create mode 100644 tools/testing/selftests/drivers/net/knod/config create mode 100755 tools/testing/selftests/drivers/net/knod/knod_attach.sh create mode 100755 tools/testing/selftests/drivers/net/knod/knod_xdp_ktime.sh create mode 100755 tools/testing/selftests/drivers/net/knod/knod_xdp_loop.sh create mode 100755 tools/testing/selftests/drivers/net/knod/lib.sh create mode 100644 tools/testing/selftests/drivers/net/knod/xdp_ktime.bpf.c create mode 100644 tools/testing/selftests/drivers/net/knod/xdp_loop.bpf.c diff --git a/tools/testing/selftests/drivers/net/knod/Makefile b/tools/testing/selftests/drivers/net/knod/Makefile new file mode 100644 index 000000000000..08138529b55e --- /dev/null +++ b/tools/testing/selftests/drivers/net/knod/Makefile @@ -0,0 +1,17 @@ +# SPDX-License-Identifier: GPL-2.0 + +TEST_PROGS := \ + knod_xdp_ktime.sh \ + knod_xdp_loop.sh \ + knod_attach.sh \ +# end of TEST_PROGS + +TEST_FILES := \ + lib.sh \ +# end of TEST_FILES + +TEST_GEN_FILES += $(patsubst %.c,%.o,$(wildcard *.bpf.c)) + +include ../../../lib.mk + +include ../../../net/bpf.mk diff --git a/tools/testing/selftests/drivers/net/knod/config b/tools/testing/selftests/drivers/net/knod/config new file mode 100644 index 000000000000..a60ece9da112 --- /dev/null +++ b/tools/testing/selftests/drivers/net/knod/config @@ -0,0 +1,7 @@ +CONFIG_BPF=y +CONFIG_BPF_SYSCALL=y +CONFIG_XDP_SOCKETS=y +CONFIG_KNOD=m +CONFIG_HSA_AMD=y +CONFIG_HSA_AMD_KNOD_BPF=m +CONFIG_DEBUG_FS=y diff --git a/tools/testing/selftests/drivers/net/knod/knod_attach.sh b/tools/testing/selftests/drivers/net/knod/knod_attach.sh new file mode 100755 index 000000000000..7ee6aca33ad8 --- /dev/null +++ b/tools/testing/selftests/drivers/net/knod/knod_attach.sh @@ -0,0 +1,135 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# knod_attach.sh - exercise the knod attach/detach control plane. +# +# Checks the NIC<->accel binding lifecycle (attach makes the pair appear in the +# xdev list, detach removes it) and that malformed or impossible attach +# requests are rejected without taking the framework down. +# +# Requires: +# - KNOD (knod + amdgpu) modules loaded +# - AMD GPU with KNOD support +# - a NIC registered with knod +# - iproute2, root +# +# Environment: +# NIC=<ifname> (required) NIC to test on +# ACCEL_ID=<id> (optional) GPU accel ID, auto-detected if omitted +# +# Exit: 0=pass, 1=fail, 4=skip + +set -o pipefail + +SELFDIR=$(dirname "$(readlink -f "$0")") +source "$SELFDIR/lib.sh" + +: "${NIC:=}" +: "${ACCEL_ID:=}" + +PASS=0 +FAIL=0 + +cleanup() { + if [ -n "$NIC" ]; then + knod_detach "$NIC" 2>/dev/null + ip link set dev "$NIC" down 2>/dev/null + fi +} +trap cleanup EXIT + +check_result() { + local desc=$1 + local ret=$2 + + if [ "$ret" -eq 0 ]; then + knod_pass "$desc" + PASS=$((PASS + 1)) + else + knod_fail "$desc" + FAIL=$((FAIL + 1)) + fi +} + +# reject == the ynl attach request fails (exit nonzero) +expect_reject() { + local desc=$1 + local json=$2 + + if knod_ynl --do attach --json "$json" 2>/dev/null; then + knod_detach "$NIC" 2>/dev/null # undo an unexpected success + check_result "$desc" 1 + else + check_result "$desc" 0 + fi +} + +# -- prereq ------------------------------------------------------ +knod_check_prereq + +if [ -z "$NIC" ]; then + knod_skip "NIC env var not set" +fi + +if ! ip link show "$NIC" >/dev/null 2>&1; then + knod_skip "NIC $NIC does not exist" +fi + +accel_id=$(knod_find_accel) +if [ -z "$accel_id" ]; then + knod_skip "no KNOD accelerator found" +fi +[ -n "$ACCEL_ID" ] && accel_id="$ACCEL_ID" + +echo "=== KNOD attach/detach control-plane test ===" +echo " NIC: $NIC" +echo " ACCEL_ID: $accel_id" +echo "" + +# attach requires the interface down; start from a known detached state +ip link set dev "$NIC" down 2>/dev/null +knod_detach "$NIC" 2>/dev/null + +# -- positive lifecycle ---------------------------------------- +knod_attach "$NIC" "$accel_id" +check_result "attach $NIC -> accel $accel_id" $? + +knod_xdev_has "$NIC" +check_result "xdev lists $NIC after attach" $? + +knod_detach "$NIC" +check_result "detach $NIC" $? + +if knod_xdev_has "$NIC"; then + check_result "xdev drops $NIC after detach" 1 +else + check_result "xdev drops $NIC after detach" 0 +fi + +# -- negative requests must be rejected ------------------------ +nic_ifindex=$(knod_ifindex "$NIC") +expect_reject "reject attach with no accel id" "{\"nic-ifindex\":$nic_ifindex}" +expect_reject "reject attach to nonexistent accel" "{\"nic-ifindex\":$nic_ifindex,\"accel-id\":999999}" +expect_reject "reject attach of nonexistent NIC" "{\"nic-ifindex\":999999,\"accel-id\":$accel_id}" + +ip link set dev "$NIC" up 2>/dev/null +expect_reject "reject attach while NIC is up" "{\"nic-ifindex\":$nic_ifindex,\"accel-id\":$accel_id}" +ip link set dev "$NIC" down 2>/dev/null + +# -- framework survived the bad requests ----------------------- +knod_kernel_alive +check_result "framework responsive after bad requests" $? + +# -- re-attach still works (state not corrupted) --------------- +knod_attach "$NIC" "$accel_id" +check_result "re-attach after errors" $? +knod_detach "$NIC" 2>/dev/null + +# -- summary -------------------------------------------------- +echo "" +echo "=== Results: $PASS passed, $FAIL failed ===" + +if [ "$FAIL" -gt 0 ]; then + exit 1 +fi +exit 0 diff --git a/tools/testing/selftests/drivers/net/knod/knod_xdp_ktime.sh b/tools/testing/selftests/drivers/net/knod/knod_xdp_ktime.sh new file mode 100755 index 000000000000..8df003052cb7 --- /dev/null +++ b/tools/testing/selftests/drivers/net/knod/knod_xdp_ktime.sh @@ -0,0 +1,173 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# knod_xdp_ktime.sh - test bpf_ktime_get_ns() on GPU XDP offload +# +# Loads an XDP program that calls bpf_ktime_get_ns() and stores +# the result in an offloaded BPF_MAP_TYPE_ARRAY, then verifies +# the GPU-side timestamp is sane. +# +# Requires: +# - KNOD (knod + amdgpu) modules loaded +# - AMD GPU with KNOD support +# - NIC with xdpoffload support (mlx5, bnxt) +# - bpftool, iproute2 +# - root privileges +# - xdp_ktime.bpf.o (built by make) +# +# Environment: +# NIC=<ifname> (required) NIC to test on +# ACCEL_ID=<id> (optional) GPU accel ID, auto-detected if omitted +# REMOTE_IP=<ip> (optional) ping target to generate traffic +# +# Exit: 0=pass, 1=fail, 4=skip + +set -o pipefail + +SELFDIR=$(dirname "$(readlink -f "$0")") +source "$SELFDIR/lib.sh" + +: "${NIC:=}" +: "${ACCEL_ID:=}" +: "${REMOTE_IP:=}" + +PASS=0 +FAIL=0 +BPF_OBJ="$SELFDIR/xdp_ktime.bpf.o" + +cleanup() { + if [ -n "$NIC" ]; then + knod_cleanup "$NIC" + fi +} +trap cleanup EXIT + +check_result() { + local desc=$1 + local ret=$2 + + if [ "$ret" -eq 0 ]; then + knod_pass "$desc" + PASS=$((PASS + 1)) + else + knod_fail "$desc" + FAIL=$((FAIL + 1)) + fi +} + +# -- prereq ------------------------------------------------------ +knod_check_prereq + +if [ -z "$NIC" ]; then + knod_skip "NIC env var not set" +fi + +if ! ip link show "$NIC" >/dev/null 2>&1; then + knod_skip "NIC $NIC does not exist" +fi + +accel_id=$(knod_find_accel) +if [ -z "$accel_id" ]; then + knod_skip "no KNOD accelerator found" +fi +[ -n "$ACCEL_ID" ] && accel_id="$ACCEL_ID" + +echo "=== KNOD XDP ktime_get_ns test ===" +echo " NIC: $NIC" +echo " ACCEL_ID: $accel_id" +echo "" + +# -- check BPF object ------------------------------------------ +if [ ! -f "$BPF_OBJ" ]; then + echo "FAIL: $BPF_OBJ not found (run make first)" + exit 1 +fi + +# -- attach NIC to GPU, select bpf feature --------------------- +ip link set dev "$NIC" down 2>/dev/null +knod_attach "$NIC" "$accel_id" +if [ $? -ne 0 ]; then + echo "FAIL: attach failed" + exit 1 +fi + +knod_feature_select "$accel_id" bpf +if [ $? -ne 0 ]; then + knod_skip "cannot select bpf feature" +fi + +# -- load XDP offload program ---------------------------------- +knod_xdp_load "$NIC" "$BPF_OBJ" +if [ $? -ne 0 ]; then + echo "FAIL: xdpoffload load failed" + exit 1 +fi + +# -- find prog/map IDs ----------------------------------------- +prog_id=$(bpftool prog show 2>/dev/null | \ + awk '/xdp_ktime_test/ {sub(/:/, "", $1); print $1; exit}') +if [ -z "$prog_id" ]; then + echo "FAIL: cannot find loaded BPF program" + exit 1 +fi +knod_log "prog_id=$prog_id" + +map_id=$(knod_get_map_id "$prog_id") +if [ -z "$map_id" ]; then + echo "FAIL: cannot find BPF map" + exit 1 +fi +knod_log "map_id=$map_id" + +# -- bring up interface and generate traffic ------------------- +ip link set dev "$NIC" up + +if [ -n "$REMOTE_IP" ]; then + knod_log "ping $REMOTE_IP to generate traffic" + ping -c 5 -W 1 "$REMOTE_IP" >/dev/null 2>&1 || true +else + knod_log "waiting for ambient traffic (10s)" + sleep 10 +fi + +# -- bring down interface before reading map ------------------ +ip link set dev "$NIC" down + +# -- read map and verify -------------------------------------- +ktime_val=$(knod_map_lookup_u64 "$map_id" 0) +pkt_count=$(knod_map_lookup_u64 "$map_id" 1) + +knod_log "ktime_ns=$ktime_val pkt_count=$pkt_count" + +# Test 1: packets were processed +rc=0 +[ "$pkt_count" -gt 0 ] || rc=1 +check_result "packets processed (count=$pkt_count)" $rc + +# Test 2: ktime is non-zero +rc=0 +[ "$ktime_val" -gt 0 ] || rc=1 +check_result "ktime non-zero ($ktime_val)" $rc + +# Test 3: ktime is within 30s of current time +if [ "$ktime_val" -gt 0 ]; then + now_ns=$(awk '{printf "%.0f", $1 * 1000000000}' /proc/uptime) + if [ -n "$now_ns" ]; then + diff=$(( now_ns - ktime_val )) + abs_diff=${diff#-} + rc=0 + [ "$abs_diff" -lt 30000000000 ] || rc=1 + check_result "ktime within 30s of wall clock (diff=${diff}ns)" $rc + else + knod_log "skipping wall clock check (/proc/uptime unavailable)" + fi +fi + +# -- summary -------------------------------------------------- +echo "" +echo "=== Results: $PASS passed, $FAIL failed ===" + +if [ "$FAIL" -gt 0 ]; then + exit 1 +fi +exit 0 diff --git a/tools/testing/selftests/drivers/net/knod/knod_xdp_loop.sh b/tools/testing/selftests/drivers/net/knod/knod_xdp_loop.sh new file mode 100755 index 000000000000..d7cba1236968 --- /dev/null +++ b/tools/testing/selftests/drivers/net/knod/knod_xdp_loop.sh @@ -0,0 +1,129 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# knod_xdp_loop.sh - the KNOD JIT must reject a bounded-loop XDP program. +# +# Loop emission is not implemented yet, so a program with a real back-edge has +# to be rejected with -EOPNOTSUPP at JIT time rather than miscompiled. This +# checks that the load fails, that the back-edge is reported to dmesg, and that +# nothing crashed or faulted in the reject path. +# +# Requires: +# - KNOD (knod + amdgpu) modules loaded +# - AMD GPU with KNOD support +# - NIC with xdpoffload support (mlx5, bnxt) +# - bpftool, iproute2, root +# - xdp_loop.bpf.o (built by make) +# +# Environment: +# NIC=<ifname> (required) NIC to test on +# ACCEL_ID=<id> (optional) GPU accel ID, auto-detected if omitted +# +# Exit: 0=pass, 1=fail, 4=skip + +set -o pipefail + +SELFDIR=$(dirname "$(readlink -f "$0")") +source "$SELFDIR/lib.sh" + +: "${NIC:=}" +: "${ACCEL_ID:=}" + +PASS=0 +FAIL=0 +BPF_OBJ="$SELFDIR/xdp_loop.bpf.o" + +cleanup() { + if [ -n "$NIC" ]; then + knod_cleanup "$NIC" + fi +} +trap cleanup EXIT + +check_result() { + local desc=$1 + local ret=$2 + + if [ "$ret" -eq 0 ]; then + knod_pass "$desc" + PASS=$((PASS + 1)) + else + knod_fail "$desc" + FAIL=$((FAIL + 1)) + fi +} + +# -- prereq ------------------------------------------------------ +knod_check_prereq + +if [ -z "$NIC" ]; then + knod_skip "NIC env var not set" +fi + +if ! ip link show "$NIC" >/dev/null 2>&1; then + knod_skip "NIC $NIC does not exist" +fi + +accel_id=$(knod_find_accel) +if [ -z "$accel_id" ]; then + knod_skip "no KNOD accelerator found" +fi +[ -n "$ACCEL_ID" ] && accel_id="$ACCEL_ID" + +if [ ! -f "$BPF_OBJ" ]; then + echo "FAIL: $BPF_OBJ not found (run make first)" + exit 1 +fi + +echo "=== KNOD XDP loop-rejection test ===" +echo " NIC: $NIC" +echo " ACCEL_ID: $accel_id" +echo "" + +# -- setup: attach NIC to GPU, then select the bpf feature ----- +# feature_select needs the accel already attached (it swaps the live +# worker), so attach first. +ip link set dev "$NIC" down 2>/dev/null +knod_attach "$NIC" "$accel_id" +if [ $? -ne 0 ]; then + echo "FAIL: attach failed" + exit 1 +fi + +knod_feature_select "$accel_id" bpf +if [ $? -ne 0 ]; then + knod_skip "cannot select bpf feature" +fi + +# remember where dmesg is now so we only scan messages from this load +dmesg_mark=$(dmesg | wc -l) + +# -- load must fail -------------------------------------------- +knod_log "loading bounded-loop program (expecting rejection)" +if knod_xdp_load "$NIC" "$BPF_OBJ" 2>/dev/null; then + # unexpectedly accepted - unload and fail + knod_xdp_unload "$NIC" + check_result "loop program rejected at load" 1 +else + check_result "loop program rejected at load" 0 +fi + +new_dmesg=$(dmesg | tail -n +"$((dmesg_mark + 1))") + +# -- back-edge reported ---------------------------------------- +rc=1 +echo "$new_dmesg" | grep -q "knod_loop:.*back-edge" && rc=0 +check_result "loop back-edge reported in dmesg" $rc + +# -- framework still alive ------------------------------------- +knod_kernel_alive +check_result "system responsive after rejection" $? + +# -- summary -------------------------------------------------- +echo "" +echo "=== Results: $PASS passed, $FAIL failed ===" + +if [ "$FAIL" -gt 0 ]; then + exit 1 +fi +exit 0 diff --git a/tools/testing/selftests/drivers/net/knod/lib.sh b/tools/testing/selftests/drivers/net/knod/lib.sh new file mode 100755 index 000000000000..d0d9b03f109d --- /dev/null +++ b/tools/testing/selftests/drivers/net/knod/lib.sh @@ -0,0 +1,181 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# lib.sh - KNOD XDP offload test utilities +# +# The KNOD control plane is the "knod" generic-netlink family; it is driven +# here through the in-tree ynl CLI (tools/net/ynl/pyynl/cli.py) so the tests +# need no dedicated user-space tool. + +KSRC=$(cd "$(dirname "${BASH_SOURCE[0]}")/../../../../../.." && pwd) +readonly KNOD_YNL="$KSRC/tools/net/ynl/pyynl/cli.py" +readonly KNOD_SPEC="$KSRC/Documentation/netlink/specs/knod.yaml" + +KNOD_NIC="" +KNOD_ACCEL_ID="" +KNOD_CLEANUP_DONE=0 + +knod_log() { echo " [INFO] $*"; } +knod_pass() { echo " [PASS] $*"; } +knod_fail() { echo " [FAIL] $*"; } +knod_skip() { echo " [SKIP] $*"; exit 4; } + +# Invoke the knod generic-netlink family via the ynl CLI. +knod_ynl() { + python3 "$KNOD_YNL" --spec "$KNOD_SPEC" "$@" +} + +knod_ifindex() { + cat "/sys/class/net/$1/ifindex" 2>/dev/null +} + +knod_check_prereq() { + if [ "$(id -u)" -ne 0 ]; then + knod_skip "must be root" + fi + + if ! command -v python3 >/dev/null 2>&1; then + knod_skip "python3 not found (needed for the ynl CLI)" + fi + + if ! command -v jq >/dev/null 2>&1; then + knod_skip "jq not found" + fi + + if ! knod_ynl --dump accel-get >/dev/null 2>&1; then + knod_skip "knod genl family not available (module not loaded?)" + fi + + if ! command -v bpftool >/dev/null 2>&1; then + knod_skip "bpftool not found" + fi + + if ! command -v ip >/dev/null 2>&1; then + knod_skip "iproute2 (ip) not found" + fi +} + +# Auto-detect the id of the first amdgpu accelerator. +knod_find_accel() { + if [ -n "$KNOD_ACCEL_ID" ]; then + echo "$KNOD_ACCEL_ID" + return 0 + fi + + knod_ynl --dump accel-get --output-json 2>/dev/null | \ + jq -r 'map(select(.name | startswith("amdgpu"))) | .[0].id // empty' +} + +# Locate the knod debugfs directory (the DRI minor number varies). +knod_debug_dir() { + local d + + for d in /sys/kernel/debug/dri/*/knod; do + [ -d "$d" ] && { echo "$d"; return 0; } + done + return 1 +} + +# Activate a KNOD offload feature ("none", "bpf", "ipsec") on <accel_id>. +knod_feature_select() { + local accel_id=$1 + local feat=$2 + + knod_log "feature_select accel $accel_id -> $feat" + knod_ynl --do accel-set \ + --json "{\"id\":$accel_id,\"feature-ena\":\"$feat\"}" >/dev/null +} + +# Confirm the framework is still responsive (used after an expected failure to +# catch an oops/hang in the reject path). The accel inventory is persistent +# (independent of attach), so a successful dump means the family is alive. +knod_kernel_alive() { + knod_ynl --dump accel-get >/dev/null 2>&1 +} + +# Is <nic> currently bound to an accel (present in the dev list)? +knod_xdev_has() { + local nic=$1 + local ifindex + + ifindex=$(knod_ifindex "$nic") || return 1 + knod_ynl --dump dev-get --output-json 2>/dev/null | \ + jq -e --argjson i "$ifindex" \ + 'any(.[]; .["nic-ifindex"] == $i)' >/dev/null +} + +knod_attach() { + local nic=$1 + local accel_id=$2 + local ifindex + + ifindex=$(knod_ifindex "$nic") || return 1 + knod_log "attach $nic (ifindex $ifindex) to accel $accel_id" + knod_ynl --do attach \ + --json "{\"nic-ifindex\":$ifindex,\"accel-id\":$accel_id}" >/dev/null +} + +knod_detach() { + local nic=$1 + local ifindex + + ifindex=$(knod_ifindex "$nic") || return 1 + knod_log "detach $nic" + knod_ynl --do detach \ + --json "{\"nic-ifindex\":$ifindex}" >/dev/null 2>&1 +} + +knod_xdp_load() { + local nic=$1 + local obj=$2 + + knod_log "xdpoffload load $obj on $nic" + ip link set dev "$nic" xdpoffload obj "$obj" sec xdp +} + +knod_xdp_unload() { + local nic=$1 + + knod_log "xdpoffload off on $nic" + ip link set dev "$nic" xdpoffload off 2>/dev/null +} + +knod_cleanup() { + local nic=$1 + + [ "$KNOD_CLEANUP_DONE" -eq 1 ] && return + KNOD_CLEANUP_DONE=1 + + knod_log "cleanup $nic" + knod_xdp_unload "$nic" + ip link set dev "$nic" down 2>/dev/null + knod_detach "$nic" +} + +knod_get_map_id() { + local prog_id=$1 + + bpftool prog show id "$prog_id" 2>/dev/null | \ + grep -o 'map_ids [0-9]*' | awk '{print $2}' +} + +knod_map_lookup_u64() { + local map_id=$1 + local key=$2 + local hex + + hex=$(bpftool map lookup id "$map_id" \ + key $key 0 0 0 2>/dev/null | \ + grep -o 'value:.*' | sed 's/value: //') + if [ -z "$hex" ]; then + echo 0 + return + fi + + printf '%d' "$(echo "$hex" | awk '{ + v = 0; + for (i = 8; i >= 1; i--) + v = v * 256 + strtonum("0x" $i); + printf "0x%x", v; + }')" +} diff --git a/tools/testing/selftests/drivers/net/knod/xdp_ktime.bpf.c b/tools/testing/selftests/drivers/net/knod/xdp_ktime.bpf.c new file mode 100644 index 000000000000..5025e41cf3e8 --- /dev/null +++ b/tools/testing/selftests/drivers/net/knod/xdp_ktime.bpf.c @@ -0,0 +1,32 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 2); + __type(key, __u32); + __type(value, __u64); +} ktime_map SEC(".maps"); + +SEC("xdp") +int xdp_ktime_test(struct xdp_md *ctx) +{ + __u32 key_ts = 0; + __u32 key_cnt = 1; + __u64 ts = bpf_ktime_get_ns(); + __u64 *cnt; + __u64 new_cnt; + + bpf_map_update_elem(&ktime_map, &key_ts, &ts, BPF_ANY); + + cnt = bpf_map_lookup_elem(&ktime_map, &key_cnt); + if (cnt) { + new_cnt = *cnt + 1; + bpf_map_update_elem(&ktime_map, &key_cnt, &new_cnt, BPF_ANY); + } + + return XDP_PASS; +} + +char LICENSE[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/drivers/net/knod/xdp_loop.bpf.c b/tools/testing/selftests/drivers/net/knod/xdp_loop.bpf.c new file mode 100644 index 000000000000..87c8251cc185 --- /dev/null +++ b/tools/testing/selftests/drivers/net/knod/xdp_loop.bpf.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +/* + * Minimal bounded-loop XDP program to exercise the KNOD JIT's loop detection. + * + * The trip count is read from the packet (runtime) and unrolling is disabled, + * so the compiler keeps a real loop with a back-edge instead of folding it + * into straight-line code. The body is an xorshift step - a non-affine + * recurrence the compiler cannot reduce to a closed form (a simple sum like + * "sum += i" gets turned into n*(n-1)/2 and the loop disappears). It touches + * no memory inside the loop, so the verifier is happy, and it has the simplest + * shape: one back-edge, a single exit (the loop condition), no break and no + * early return. + */ +SEC("xdp") +int xdp_loop_test(struct xdp_md *ctx) +{ + void *data = (void *)(long)ctx->data; + void *data_end = (void *)(long)ctx->data_end; + __u8 *pkt = data; + __u32 sum; + int i, n; + + if ((void *)(pkt + 1) > data_end) + return XDP_DROP; + + n = pkt[0] & 0x3f; /* runtime bound, 0..63 */ + sum = pkt[0] | 1; /* nonzero xorshift seed */ + +#pragma clang loop unroll(disable) + for (i = 0; i < n; i++) { + sum ^= sum << 13; + sum ^= sum >> 17; + sum ^= sum << 5; + } + + return (sum & 1) ? XDP_PASS : XDP_DROP; +} + +char LICENSE[] SEC("license") = "GPL"; -- 2.43.0
