selftests: virtio_net: add initial tests

Introduce initial tests for virtio_net driver. Focus on feature testing
leveraging previously introduced debugfs feature filtering
infrastructure. Add very basic ping and F_MAC feature tests.

To run this, do:
$ make -C tools/testing/selftests/ TARGETS=drivers/net/virtio_net/ run_tests

Run it on a system with 2 virtio_net devices connected back-to-back
on the hypervisor.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Tested-by: Benjamin Poirier <bpoirier@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

MAINTAINERS

@@ -23466,6 +23466,7 @@ F:	include/linux/virtio*.h
 F:	include/linux/vringh.h
 F:	include/uapi/linux/virtio_*.h
 F:	tools/virtio/
+F:	tools/testing/selftests/drivers/net/virtio_net/
 
 VIRTIO CRYPTO DRIVER
 M:	Gonglei <arei.gonglei@huawei.com>

tools/testing/selftests/Makefile

@@ -20,6 +20,7 @@ TARGETS += drivers/s390x/uvdevice
 TARGETS += drivers/net
 TARGETS += drivers/net/bonding
 TARGETS += drivers/net/team
+TARGETS += drivers/net/virtio_net
 TARGETS += dt
 TARGETS += efivarfs
 TARGETS += exec

tools/testing/selftests/drivers/net/virtio_net/Makefile

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0+ OR MIT
+
+TEST_PROGS = basic_features.sh \
+        #
+
+TEST_FILES = \
+        virtio_net_common.sh \
+        #
+
+TEST_INCLUDES = \
+        ../../../net/forwarding/lib.sh \
+        ../../../net/lib.sh \
+        #
+
+include ../../../lib.mk

tools/testing/selftests/drivers/net/virtio_net/basic_features.sh

@@ -0,0 +1,131 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# See virtio_net_common.sh comments for more details about assumed setup
+
+ALL_TESTS="
+	initial_ping_test
+	f_mac_test
+"
+
+source virtio_net_common.sh
+
+lib_dir=$(dirname "$0")
+source "$lib_dir"/../../../net/forwarding/lib.sh
+
+h1=${NETIFS[p1]}
+h2=${NETIFS[p2]}
+
+h1_create()
+{
+	simple_if_init $h1 $H1_IPV4/24 $H1_IPV6/64
+}
+
+h1_destroy()
+{
+	simple_if_fini $h1 $H1_IPV4/24 $H1_IPV6/64
+}
+
+h2_create()
+{
+	simple_if_init $h2 $H2_IPV4/24 $H2_IPV6/64
+}
+
+h2_destroy()
+{
+	simple_if_fini $h2 $H2_IPV4/24 $H2_IPV6/64
+}
+
+initial_ping_test()
+{
+	setup_cleanup
+	setup_prepare
+	ping_test $h1 $H2_IPV4 " simple"
+}
+
+f_mac_test()
+{
+	RET=0
+	local test_name="mac feature filtered"
+
+	virtio_feature_present $h1 $VIRTIO_NET_F_MAC
+	if [ $? -ne 0 ]; then
+		log_test_skip "$test_name" "Device $h1 is missing feature $VIRTIO_NET_F_MAC."
+		return 0
+	fi
+	virtio_feature_present $h1 $VIRTIO_NET_F_MAC
+	if [ $? -ne 0 ]; then
+		log_test_skip "$test_name" "Device $h2 is missing feature $VIRTIO_NET_F_MAC."
+		return 0
+	fi
+
+	setup_cleanup
+	setup_prepare
+
+	grep -q 0 /sys/class/net/$h1/addr_assign_type
+	check_err $? "Permanent address assign type for $h1 is not set"
+	grep -q 0 /sys/class/net/$h2/addr_assign_type
+	check_err $? "Permanent address assign type for $h2 is not set"
+
+	setup_cleanup
+	virtio_filter_feature_add $h1 $VIRTIO_NET_F_MAC
+	virtio_filter_feature_add $h2 $VIRTIO_NET_F_MAC
+	setup_prepare
+
+	grep -q 0 /sys/class/net/$h1/addr_assign_type
+	check_fail $? "Permanent address assign type for $h1 is set when F_MAC feature is filtered"
+	grep -q 0 /sys/class/net/$h2/addr_assign_type
+	check_fail $? "Permanent address assign type for $h2 is set when F_MAC feature is filtered"
+
+	ping_do $h1 $H2_IPV4
+	check_err $? "Ping failed"
+
+	log_test "$test_name"
+}
+
+setup_prepare()
+{
+	virtio_device_rebind $h1
+	virtio_device_rebind $h2
+	wait_for_dev $h1
+	wait_for_dev $h2
+
+	vrf_prepare
+
+	h1_create
+	h2_create
+}
+
+setup_cleanup()
+{
+	h2_destroy
+	h1_destroy
+
+	vrf_cleanup
+
+	virtio_filter_features_clear $h1
+	virtio_filter_features_clear $h2
+	virtio_device_rebind $h1
+	virtio_device_rebind $h2
+	wait_for_dev $h1
+	wait_for_dev $h2
+}
+
+cleanup()
+{
+	pre_cleanup
+	setup_cleanup
+}
+
+check_driver $h1 "virtio_net"
+check_driver $h2 "virtio_net"
+check_virtio_debugfs $h1
+check_virtio_debugfs $h2
+
+trap cleanup EXIT
+
+setup_prepare
+
+tests_run
+
+exit "$EXIT_STATUS"

tools/testing/selftests/drivers/net/virtio_net/config

@@ -0,0 +1,2 @@
+CONFIG_VIRTIO_NET=y
+CONFIG_VIRTIO_DEBUG=y

tools/testing/selftests/drivers/net/virtio_net/virtio_net_common.sh

@@ -0,0 +1,99 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# This assumes running on a host with two virtio interfaces connected
+# back to back. Example script to do such wire-up of tap devices would
+# look like this:
+#
+# =======================================================================================================
+# #!/bin/bash
+#
+# DEV1="$1"
+# DEV2="$2"
+#
+# sudo tc qdisc add dev $DEV1 clsact
+# sudo tc qdisc add dev $DEV2 clsact
+# sudo tc filter add dev $DEV1 ingress protocol all pref 1 matchall action mirred egress redirect dev $DEV2
+# sudo tc filter add dev $DEV2 ingress protocol all pref 1 matchall action mirred egress redirect dev $DEV1
+# sudo ip link set $DEV1 up
+# sudo ip link set $DEV2 up
+# =======================================================================================================
+
+REQUIRE_MZ="no"
+NETIF_CREATE="no"
+NETIF_FIND_DRIVER="virtio_net"
+NUM_NETIFS=2
+
+H1_IPV4="192.0.2.1"
+H2_IPV4="192.0.2.2"
+H1_IPV6="2001:db8:1::1"
+H2_IPV6="2001:db8:1::2"
+
+VIRTIO_NET_F_MAC=5
+
+virtio_device_get()
+{
+	local dev=$1; shift
+	local device_path="/sys/class/net/$dev/device/"
+
+	basename `realpath $device_path`
+}
+
+virtio_device_rebind()
+{
+	local dev=$1; shift
+	local device=`virtio_device_get $dev`
+
+	echo "$device" > /sys/bus/virtio/drivers/virtio_net/unbind
+	echo "$device" > /sys/bus/virtio/drivers/virtio_net/bind
+}
+
+virtio_debugfs_get()
+{
+	local dev=$1; shift
+	local device=`virtio_device_get $dev`
+
+	echo /sys/kernel/debug/virtio/$device/
+}
+
+check_virtio_debugfs()
+{
+	local dev=$1; shift
+	local debugfs=`virtio_debugfs_get $dev`
+
+	if [ ! -f "$debugfs/device_features" ] ||
+	   [ ! -f "$debugfs/filter_feature_add"  ] ||
+	   [ ! -f "$debugfs/filter_feature_del"  ] ||
+	   [ ! -f "$debugfs/filter_features"  ] ||
+	   [ ! -f "$debugfs/filter_features_clear"  ]; then
+		echo "SKIP: not possible to access debugfs for $dev"
+		exit $ksft_skip
+	fi
+}
+
+virtio_feature_present()
+{
+	local dev=$1; shift
+	local feature=$1; shift
+	local debugfs=`virtio_debugfs_get $dev`
+
+	cat $debugfs/device_features |grep "^$feature$" &> /dev/null
+	return $?
+}
+
+virtio_filter_features_clear()
+{
+	local dev=$1; shift
+	local debugfs=`virtio_debugfs_get $dev`
+
+	echo "1" > $debugfs/filter_features_clear
+}
+
+virtio_filter_feature_add()
+{
+	local dev=$1; shift
+	local feature=$1; shift
+	local debugfs=`virtio_debugfs_get $dev`
+
+	echo "$feature" > $debugfs/filter_feature_add
+}