selftests: mlxsw: Add headroom handling test

Add a test for headroom configuration. This covers projection of ETS
configuration to ingress, PFC, adjustments for MTU, the qdisc / TC
mode and the effect of egress SPAN session on buffer configuration.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/drivers/net/mlxsw/qos_headroom.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+ALL_TESTS="
+	test_defaults
+	test_dcb_ets
+	test_mtu
+	test_pfc
+	test_int_buf
+	test_tc_priomap
+	test_tc_mtu
+	test_tc_sizes
+	test_tc_int_buf
+"
+
+lib_dir=$(dirname $0)/../../../net/forwarding
+
+NUM_NETIFS=0
+source $lib_dir/lib.sh
+source $lib_dir/devlink_lib.sh
+source qos_lib.sh
+
+swp=$NETIF_NO_CABLE
+
+cleanup()
+{
+	pre_cleanup
+}
+
+get_prio_pg()
+{
+	__mlnx_qos -i $swp | sed -n '/^PFC/,/^[^[:space:]]/p' |
+		grep buffer | sed 's/ \+/ /g' | cut -d' ' -f 2-
+}
+
+get_prio_pfc()
+{
+	__mlnx_qos -i $swp | sed -n '/^PFC/,/^[^[:space:]]/p' |
+		grep enabled | sed 's/ \+/ /g' | cut -d' ' -f 2-
+}
+
+get_prio_tc()
+{
+	__mlnx_qos -i $swp | sed -n '/^tc/,$p' |
+		awk '/^tc/ { TC = $2 }
+		     /priority:/ { PRIO[$2]=TC }
+		     END {
+			for (i in PRIO)
+			    printf("%d ", PRIO[i])
+		     }'
+}
+
+get_buf_size()
+{
+	local idx=$1; shift
+
+	__mlnx_qos -i $swp | grep Receive | sed 's/.*: //' | cut -d, -f $((idx + 1))
+}
+
+get_tot_size()
+{
+	__mlnx_qos -i $swp | grep Receive | sed 's/.*total_size=//'
+}
+
+check_prio_pg()
+{
+	local expect=$1; shift
+
+	local current=$(get_prio_pg)
+	test "$current" = "$expect"
+	check_err $? "prio2buffer is '$current', expected '$expect'"
+}
+
+check_prio_pfc()
+{
+	local expect=$1; shift
+
+	local current=$(get_prio_pfc)
+	test "$current" = "$expect"
+	check_err $? "prio PFC is '$current', expected '$expect'"
+}
+
+check_prio_tc()
+{
+	local expect=$1; shift
+
+	local current=$(get_prio_tc)
+	test "$current" = "$expect"
+	check_err $? "prio_tc is '$current', expected '$expect'"
+}
+
+__check_buf_size()
+{
+	local idx=$1; shift
+	local expr=$1; shift
+	local what=$1; shift
+
+	local current=$(get_buf_size $idx)
+	((current $expr))
+	check_err $? "${what}buffer $idx size is '$current', expected '$expr'"
+	echo $current
+}
+
+check_buf_size()
+{
+	__check_buf_size "$@" > /dev/null
+}
+
+test_defaults()
+{
+	RET=0
+
+	check_prio_pg "0 0 0 0 0 0 0 0 "
+	check_prio_tc "0 0 0 0 0 0 0 0 "
+	check_prio_pfc "0 0 0 0 0 0 0 0 "
+
+	log_test "Default headroom configuration"
+}
+
+test_dcb_ets()
+{
+	RET=0
+
+	__mlnx_qos -i $swp --prio_tc=0,2,4,6,1,3,5,7 > /dev/null
+
+	check_prio_pg "0 2 4 6 1 3 5 7 "
+	check_prio_tc "0 2 4 6 1 3 5 7 "
+	check_prio_pfc "0 0 0 0 0 0 0 0 "
+
+	__mlnx_qos -i $swp --prio_tc=0,0,0,0,0,0,0,0 > /dev/null
+
+	check_prio_pg "0 0 0 0 0 0 0 0 "
+	check_prio_tc "0 0 0 0 0 0 0 0 "
+
+	__mlnx_qos -i $swp --prio2buffer=1,3,5,7,0,2,4,6 &> /dev/null
+	check_fail $? "prio2buffer accepted in DCB mode"
+
+	log_test "Configuring headroom through ETS"
+}
+
+test_mtu()
+{
+	local what=$1; shift
+	local buf0size_2
+	local buf0size
+
+	RET=0
+	buf0size=$(__check_buf_size 0 "> 0")
+
+	mtu_set $swp 3000
+	buf0size_2=$(__check_buf_size 0 "> $buf0size" "MTU 3000: ")
+	mtu_restore $swp
+
+	mtu_set $swp 6000
+	check_buf_size 0 "> $buf0size_2" "MTU 6000: "
+	mtu_restore $swp
+
+	check_buf_size 0 "== $buf0size"
+
+	log_test "${what}MTU impacts buffer size"
+}
+
+test_tc_mtu()
+{
+	# In TC mode, MTU still impacts the threshold below which a buffer is
+	# not permitted to go.
+
+	tc qdisc replace dev $swp root handle 1: bfifo limit 1.5M
+	test_mtu "TC: "
+	tc qdisc delete dev $swp root
+}
+
+test_pfc()
+{
+	RET=0
+
+	__mlnx_qos -i $swp --prio_tc=0,0,0,0,0,1,2,3 > /dev/null
+
+	local buf0size=$(get_buf_size 0)
+	local buf1size=$(get_buf_size 1)
+	local buf2size=$(get_buf_size 2)
+	local buf3size=$(get_buf_size 3)
+	check_buf_size 0 "> 0"
+	check_buf_size 1 "> 0"
+	check_buf_size 2 "> 0"
+	check_buf_size 3 "> 0"
+	check_buf_size 4 "== 0"
+	check_buf_size 5 "== 0"
+	check_buf_size 6 "== 0"
+	check_buf_size 7 "== 0"
+
+	log_test "Buffer size sans PFC"
+
+	RET=0
+
+	__mlnx_qos -i $swp --pfc=0,0,0,0,0,1,1,1 --cable_len=0 > /dev/null
+
+	check_prio_pg "0 0 0 0 0 1 2 3 "
+	check_prio_pfc "0 0 0 0 0 1 1 1 "
+	check_buf_size 0 "== $buf0size"
+	check_buf_size 1 "> $buf1size"
+	check_buf_size 2 "> $buf2size"
+	check_buf_size 3 "> $buf3size"
+
+	local buf1size=$(get_buf_size 1)
+	check_buf_size 2 "== $buf1size"
+	check_buf_size 3 "== $buf1size"
+
+	log_test "PFC: Cable length 0"
+
+	RET=0
+
+	__mlnx_qos -i $swp --pfc=0,0,0,0,0,1,1,1 --cable_len=1000 > /dev/null
+
+	check_buf_size 0 "== $buf0size"
+	check_buf_size 1 "> $buf1size"
+	check_buf_size 2 "> $buf1size"
+	check_buf_size 3 "> $buf1size"
+
+	log_test "PFC: Cable length 1000"
+
+	RET=0
+
+	__mlnx_qos -i $swp --pfc=0,0,0,0,0,0,0,0 --cable_len=0 > /dev/null
+	__mlnx_qos -i $swp --prio_tc=0,0,0,0,0,0,0,0 > /dev/null
+
+	check_prio_pg "0 0 0 0 0 0 0 0 "
+	check_prio_tc "0 0 0 0 0 0 0 0 "
+	check_buf_size 0 "> 0"
+	check_buf_size 1 "== 0"
+	check_buf_size 2 "== 0"
+	check_buf_size 3 "== 0"
+	check_buf_size 4 "== 0"
+	check_buf_size 5 "== 0"
+	check_buf_size 6 "== 0"
+	check_buf_size 7 "== 0"
+
+	log_test "PFC: Restore defaults"
+}
+
+test_tc_priomap()
+{
+	RET=0
+
+	__mlnx_qos -i $swp --prio_tc=0,1,2,3,4,5,6,7 > /dev/null
+	check_prio_pg "0 1 2 3 4 5 6 7 "
+
+	tc qdisc replace dev $swp root handle 1: bfifo limit 1.5M
+	check_prio_pg "0 0 0 0 0 0 0 0 "
+
+	__mlnx_qos -i $swp --prio2buffer=1,3,5,7,0,2,4,6 > /dev/null
+	check_prio_pg "1 3 5 7 0 2 4 6 "
+
+	tc qdisc delete dev $swp root
+	check_prio_pg "0 1 2 3 4 5 6 7 "
+
+	# Clean up.
+	tc qdisc replace dev $swp root handle 1: bfifo limit 1.5M
+	__mlnx_qos -i $swp --prio2buffer=0,0,0,0,0,0,0,0 > /dev/null
+	tc qdisc delete dev $swp root
+	__mlnx_qos -i $swp --prio_tc=0,0,0,0,0,0,0,0 > /dev/null
+
+	log_test "TC: priomap"
+}
+
+test_tc_sizes()
+{
+	local cell_size=$(devlink_cell_size_get)
+	local size=$((cell_size * 1000))
+
+	RET=0
+
+	__mlnx_qos -i $swp --buffer_size=$size,0,0,0,0,0,0,0 &> /dev/null
+	check_fail $? "buffer_size should fail before qdisc is added"
+
+	tc qdisc replace dev $swp root handle 1: bfifo limit 1.5M
+
+	__mlnx_qos -i $swp --buffer_size=$size,0,0,0,0,0,0,0 > /dev/null
+	check_err $? "buffer_size should pass after qdisc is added"
+	check_buf_size 0 "== $size" "set size: "
+
+	mtu_set $swp 6000
+	check_buf_size 0 "== $size" "set MTU: "
+	mtu_restore $swp
+
+	__mlnx_qos -i $swp --buffer_size=0,0,0,0,0,0,0,0 > /dev/null
+
+	# After replacing the qdisc for the same kind, buffer_size still has to
+	# work.
+	tc qdisc replace dev $swp root handle 1: bfifo limit 1M
+
+	__mlnx_qos -i $swp --buffer_size=$size,0,0,0,0,0,0,0 > /dev/null
+	check_buf_size 0 "== $size" "post replace, set size: "
+
+	__mlnx_qos -i $swp --buffer_size=0,0,0,0,0,0,0,0 > /dev/null
+
+	# Likewise after replacing for a different kind.
+	tc qdisc replace dev $swp root handle 2: prio bands 8
+
+	__mlnx_qos -i $swp --buffer_size=$size,0,0,0,0,0,0,0 > /dev/null
+	check_buf_size 0 "== $size" "post replace different kind, set size: "
+
+	tc qdisc delete dev $swp root
+
+	__mlnx_qos -i $swp --buffer_size=$size,0,0,0,0,0,0,0 &> /dev/null
+	check_fail $? "buffer_size should fail after qdisc is deleted"
+
+	log_test "TC: buffer size"
+}
+
+test_int_buf()
+{
+	local what=$1; shift
+
+	RET=0
+
+	local buf0size=$(get_buf_size 0)
+	local tot_size=$(get_tot_size)
+
+	# Size of internal buffer and buffer 9.
+	local dsize=$((tot_size - buf0size))
+
+	tc qdisc add dev $swp clsact
+	tc filter add dev $swp egress matchall skip_sw action mirred egress mirror dev $swp
+
+	local buf0size_2=$(get_buf_size 0)
+	local tot_size_2=$(get_tot_size)
+	local dsize_2=$((tot_size_2 - buf0size_2))
+
+	# Egress SPAN should have added to the "invisible" buffer configuration.
+	((dsize_2 > dsize))
+	check_err $? "Invisible buffers account for '$dsize_2', expected '> $dsize'"
+
+	mtu_set $swp 3000
+
+	local buf0size_3=$(get_buf_size 0)
+	local tot_size_3=$(get_tot_size)
+	local dsize_3=$((tot_size_3 - buf0size_3))
+
+	# MTU change might change buffer 0, which will show at total, but the
+	# hidden buffers should stay the same size.
+	((dsize_3 == dsize_2))
+	check_err $? "MTU change: Invisible buffers account for '$dsize_3', expected '== $dsize_2'"
+
+	mtu_restore $swp
+	tc qdisc del dev $swp clsact
+
+	# After SPAN removal, hidden buffers should be back to the original sizes.
+	local buf0size_4=$(get_buf_size 0)
+	local tot_size_4=$(get_tot_size)
+	local dsize_4=$((tot_size_4 - buf0size_4))
+	((dsize_4 == dsize))
+	check_err $? "SPAN removed: Invisible buffers account for '$dsize_4', expected '== $dsize'"
+
+	log_test "${what}internal buffer size"
+}
+
+test_tc_int_buf()
+{
+	local cell_size=$(devlink_cell_size_get)
+	local size=$((cell_size * 1000))
+
+	tc qdisc replace dev $swp root handle 1: bfifo limit 1.5M
+	test_int_buf "TC: "
+
+	__mlnx_qos -i $swp --buffer_size=$size,0,0,0,0,0,0,0 > /dev/null
+	test_int_buf "TC+buffsize: "
+
+	__mlnx_qos -i $swp --buffer_size=0,0,0,0,0,0,0,0 > /dev/null
+	tc qdisc delete dev $swp root
+}
+
+trap cleanup EXIT
+
+bail_on_lldpad
+setup_wait
+tests_run
+
+exit $EXIT_STATUS