netdevsim: add pause frame stats

Add minimal ethtool interface for testing ethtool pause stats.

v2: add missing static on nsim_ethtool_ops

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/netdevsim/Makefile

@@ -3,7 +3,7 @@
 obj-$(CONFIG_NETDEVSIM) += netdevsim.o
 
 netdevsim-objs := \
-	netdev.o dev.o fib.o bus.o health.o udp_tunnels.o
+	netdev.o dev.o ethtool.o fib.o bus.o health.o udp_tunnels.o
 
 ifeq ($(CONFIG_BPF_SYSCALL),y)
 netdevsim-objs += \

drivers/net/netdevsim/ethtool.c

@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+
+#include <linux/debugfs.h>
+#include <linux/ethtool.h>
+#include <linux/random.h>
+
+#include "netdevsim.h"
+
+static void
+nsim_get_pause_stats(struct net_device *dev,
+		     struct ethtool_pause_stats *pause_stats)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+
+	if (ns->ethtool.report_stats_rx)
+		pause_stats->rx_pause_frames = 1;
+	if (ns->ethtool.report_stats_tx)
+		pause_stats->tx_pause_frames = 2;
+}
+
+static void
+nsim_get_pauseparam(struct net_device *dev, struct ethtool_pauseparam *pause)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+
+	pause->autoneg = 0; /* We don't support ksettings, so can't pretend */
+	pause->rx_pause = ns->ethtool.rx;
+	pause->tx_pause = ns->ethtool.tx;
+}
+
+static int
+nsim_set_pauseparam(struct net_device *dev, struct ethtool_pauseparam *pause)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+
+	if (pause->autoneg)
+		return -EINVAL;
+
+	ns->ethtool.rx = pause->rx_pause;
+	ns->ethtool.tx = pause->tx_pause;
+	return 0;
+}
+
+static const struct ethtool_ops nsim_ethtool_ops = {
+	.get_pause_stats	= nsim_get_pause_stats,
+	.get_pauseparam		= nsim_get_pauseparam,
+	.set_pauseparam		= nsim_set_pauseparam,
+};
+
+void nsim_ethtool_init(struct netdevsim *ns)
+{
+	struct dentry *ethtool, *dir;
+
+	ns->netdev->ethtool_ops = &nsim_ethtool_ops;
+
+	ethtool = debugfs_create_dir("ethtool", ns->nsim_dev->ddir);
+
+	dir = debugfs_create_dir("pause", ethtool);
+	debugfs_create_bool("report_stats_rx", 0600, dir,
+			    &ns->ethtool.report_stats_rx);
+	debugfs_create_bool("report_stats_tx", 0600, dir,
+			    &ns->ethtool.report_stats_tx);
+}

drivers/net/netdevsim/netdev.c

@@ -301,6 +301,7 @@ nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port)
 	ns->nsim_bus_dev = nsim_dev->nsim_bus_dev;
 	SET_NETDEV_DEV(dev, &ns->nsim_bus_dev->dev);
 	dev->netdev_ops = &nsim_netdev_ops;
+	nsim_ethtool_init(ns);
 
 	err = nsim_udp_tunnels_info_create(nsim_dev, dev);
 	if (err)

drivers/net/netdevsim/netdevsim.h

@@ -50,6 +50,13 @@ struct nsim_ipsec {
 	u32 ok;
 };
 
+struct nsim_ethtool {
+	bool rx;
+	bool tx;
+	bool report_stats_rx;
+	bool report_stats_tx;
+};
+
 struct netdevsim {
 	struct net_device *netdev;
 	struct nsim_dev *nsim_dev;
@@ -80,12 +87,16 @@ struct netdevsim {
 		u32 ports[2][NSIM_UDP_TUNNEL_N_PORTS];
 		struct debugfs_u32_array dfs_ports[2];
 	} udp_ports;
+
+	struct nsim_ethtool ethtool;
 };
 
 struct netdevsim *
 nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port);
 void nsim_destroy(struct netdevsim *ns);
 
+void nsim_ethtool_init(struct netdevsim *ns);
+
 void nsim_udp_tunnels_debugfs_create(struct nsim_dev *nsim_dev);
 int nsim_udp_tunnels_info_create(struct nsim_dev *nsim_dev,
 				 struct net_device *dev);