diff --git a/tools/testing/selftests/drivers/net/mlxsw/mlxsw_lib.sh b/tools/testing/selftests/drivers/net/mlxsw/mlxsw_lib.sh
index a95856aafd2aba07086482ae51f560491b8d8d36..6369927e9c378b015842fb600e88e8da621f7d1f 100644
--- a/tools/testing/selftests/drivers/net/mlxsw/mlxsw_lib.sh
+++ b/tools/testing/selftests/drivers/net/mlxsw/mlxsw_lib.sh
@@ -61,3 +61,17 @@ mlxsw_only_on_spectrum()
 
 	return 1
 }
+
+mlxsw_max_descriptors_get()
+{
+	local spectrum_rev=$MLXSW_SPECTRUM_REV
+
+	case $spectrum_rev in
+	1) echo 81920 ;;
+	2) echo 136960 ;;
+	3) echo 204800 ;;
+	4) echo 220000 ;;
+	*) echo "Unknown max descriptors for chip revision." > /dev/stderr
+	   return 1 ;;
+	esac
+}
diff --git a/tools/testing/selftests/drivers/net/mlxsw/qos_max_descriptors.sh b/tools/testing/selftests/drivers/net/mlxsw/qos_max_descriptors.sh
new file mode 100755
index 0000000000000000000000000000000000000000..5ac4f795e333b49229b5bc42c618057e635424da
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/mlxsw/qos_max_descriptors.sh
@@ -0,0 +1,282 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# This test sends many small packets (size is less than cell size) through the
+# switch. A shaper is used in $swp2, so the traffic is limited there. Packets
+# are queued till they will be sent.
+#
+# The idea is to verify that the switch can handle at least 85% of maximum
+# supported descrpitors by hardware. Then, we verify that the driver configures
+# firmware to allow infinite size of egress descriptor pool, and does not use a
+# lower limitation. Increase the size of the relevant pools such that the pool's
+# size does not limit the traffic.
+
+# +-----------------------+
+# | H1                    |
+# |   + $h1.111           |
+# |   | 192.0.2.33/28     |
+# |   |                   |
+# |   + $h1               |
+# +---|-------------------+
+#     |
+# +---|-----------------------------+
+# |   + $swp1                       |
+# |   | iPOOL1                      |
+# |   |                             |
+# | +-|------------------------+    |
+# | | + $swp1.111              |    |
+# | |                          |    |
+# | | BR1                      |    |
+# | |                          |    |
+# | | + $swp2.111              |    |
+# | +-|------------------------+    |
+# |   |                             |
+# |   + $swp2                       |
+# |   | ePOOL6                      |
+# |   | 1mbit                       |
+# +---+-----------------------------+
+#     |
+# +---|-------------------+
+# |   + $h2            H2 |
+# |   |                   |
+# |   + $h2.111           |
+# |     192.0.2.34/28     |
+# +-----------------------+
+#
+
+ALL_TESTS="
+	ping_ipv4
+	max_descriptors
+"
+
+lib_dir=$(dirname $0)/../../../net/forwarding
+
+NUM_NETIFS=4
+source $lib_dir/lib.sh
+source $lib_dir/devlink_lib.sh
+source mlxsw_lib.sh
+
+MAX_POOL_SIZE=$(devlink_pool_size_get)
+SHAPER_RATE=1mbit
+
+# The current TBF qdisc interface does not allow us to configure the shaper to
+# flat zero. The ASIC shaper is guaranteed to work with a granularity of
+# 200Mbps. On Spectrum-2, writing a value close to zero instead of zero works
+# well, but the performance on Spectrum-1 is unpredictable. Thus, do not run the
+# test on Spectrum-1.
+mlxsw_only_on_spectrum 2+ || exit
+
+h1_create()
+{
+	simple_if_init $h1
+
+	vlan_create $h1 111 v$h1 192.0.2.33/28
+	ip link set dev $h1.111 type vlan egress-qos-map 0:1
+}
+
+h1_destroy()
+{
+	vlan_destroy $h1 111
+
+	simple_if_fini $h1
+}
+
+h2_create()
+{
+	simple_if_init $h2
+
+	vlan_create $h2 111 v$h2 192.0.2.34/28
+}
+
+h2_destroy()
+{
+	vlan_destroy $h2 111
+
+	simple_if_fini $h2
+}
+
+switch_create()
+{
+	# pools
+	# -----
+
+	devlink_pool_size_thtype_save 1
+	devlink_pool_size_thtype_save 6
+
+	devlink_port_pool_th_save $swp1 1
+	devlink_port_pool_th_save $swp2 6
+
+	devlink_tc_bind_pool_th_save $swp1 1 ingress
+	devlink_tc_bind_pool_th_save $swp2 1 egress
+
+	devlink_pool_size_thtype_set 1 dynamic $MAX_POOL_SIZE
+	devlink_pool_size_thtype_set 6 static $MAX_POOL_SIZE
+
+	# $swp1
+	# -----
+
+	ip link set dev $swp1 up
+	vlan_create $swp1 111
+	ip link set dev $swp1.111 type vlan ingress-qos-map 0:0 1:1
+
+	devlink_port_pool_th_set $swp1 1 16
+	devlink_tc_bind_pool_th_set $swp1 1 ingress 1 16
+
+	tc qdisc replace dev $swp1 root handle 1: \
+	   ets bands 8 strict 8 priomap 7 6
+	dcb buffer set dev $swp1 prio-buffer all:0 1:1
+
+	# $swp2
+	# -----
+
+	ip link set dev $swp2 up
+	vlan_create $swp2 111
+	ip link set dev $swp2.111 type vlan egress-qos-map 0:0 1:1
+
+	devlink_port_pool_th_set $swp2 6 $MAX_POOL_SIZE
+	devlink_tc_bind_pool_th_set $swp2 1 egress 6 $MAX_POOL_SIZE
+
+	tc qdisc replace dev $swp2 root handle 1: tbf rate $SHAPER_RATE \
+		burst 128K limit 500M
+	tc qdisc replace dev $swp2 parent 1:1 handle 11: \
+		ets bands 8 strict 8 priomap 7 6
+
+	# bridge
+	# ------
+
+	ip link add name br1 type bridge vlan_filtering 0
+	ip link set dev $swp1.111 master br1
+	ip link set dev br1 up
+
+	ip link set dev $swp2.111 master br1
+}
+
+switch_destroy()
+{
+	# Do this first so that we can reset the limits to values that are only
+	# valid for the original static / dynamic setting.
+	devlink_pool_size_thtype_restore 6
+	devlink_pool_size_thtype_restore 1
+
+	# bridge
+	# ------
+
+	ip link set dev $swp2.111 nomaster
+
+	ip link set dev br1 down
+	ip link set dev $swp1.111 nomaster
+	ip link del dev br1
+
+	# $swp2
+	# -----
+
+	tc qdisc del dev $swp2 parent 1:1 handle 11:
+	tc qdisc del dev $swp2 root
+
+	devlink_tc_bind_pool_th_restore $swp2 1 egress
+	devlink_port_pool_th_restore $swp2 6
+
+	vlan_destroy $swp2 111
+	ip link set dev $swp2 down
+
+	# $swp1
+	# -----
+
+	dcb buffer set dev $swp1 prio-buffer all:0
+	tc qdisc del dev $swp1 root
+
+	devlink_tc_bind_pool_th_restore $swp1 1 ingress
+	devlink_port_pool_th_restore $swp1 1
+
+	vlan_destroy $swp1 111
+	ip link set dev $swp1 down
+}
+
+setup_prepare()
+{
+	h1=${NETIFS[p1]}
+	swp1=${NETIFS[p2]}
+
+	swp2=${NETIFS[p3]}
+	h2=${NETIFS[p4]}
+
+	h2mac=$(mac_get $h2)
+
+	vrf_prepare
+
+	h1_create
+	h2_create
+	switch_create
+}
+
+cleanup()
+{
+	pre_cleanup
+
+	switch_destroy
+	h2_destroy
+	h1_destroy
+
+	vrf_cleanup
+}
+
+ping_ipv4()
+{
+	ping_test $h1 192.0.2.34 " h1->h2"
+}
+
+percentage_used()
+{
+	local num_packets=$1; shift
+	local max_packets=$1; shift
+
+	bc <<< "
+	    scale=2
+	    100 * $num_packets / $max_packets
+	"
+}
+
+max_descriptors()
+{
+	local cell_size=$(devlink_cell_size_get)
+	local exp_perc_used=85
+	local max_descriptors
+	local pktsize=30
+
+	RET=0
+
+	max_descriptors=$(mlxsw_max_descriptors_get) || exit 1
+
+	local d0=$(ethtool_stats_get $swp2 tc_no_buffer_discard_uc_tc_1)
+
+	log_info "Send many small packets, packet size = $pktsize bytes"
+	start_traffic_pktsize $pktsize $h1.111 192.0.2.33 192.0.2.34 $h2mac
+
+	# Sleep to wait for congestion.
+	sleep 5
+
+	local d1=$(ethtool_stats_get $swp2 tc_no_buffer_discard_uc_tc_1)
+	((d1 == d0))
+	check_err $? "Drops seen on egress port: $d0 -> $d1 ($((d1 - d0)))"
+
+	# Check how many packets the switch can handle, the limitation is
+	# maximum descriptors.
+	local pkts_bytes=$(ethtool_stats_get $swp2 tc_transmit_queue_tc_1)
+	local pkts_num=$((pkts_bytes / cell_size))
+	local perc_used=$(percentage_used $pkts_num $max_descriptors)
+
+	check_err $(bc <<< "$perc_used < $exp_perc_used") \
+		"Expected > $exp_perc_used% of descriptors, handle $perc_used%"
+
+	stop_traffic
+	sleep 1
+
+	log_test "Maximum descriptors usage. The percentage used is $perc_used%"
+}
+
+trap cleanup EXIT
+setup_prepare
+setup_wait
+tests_run
+
+exit $EXIT_STATUS