Re: [PATCH net-next 1/2] netdevsim: add link speed support

On Tue, Sep 01, 2026 at 02:43:39PM +0200, Andrew Lunn wrote:

On Tue, Sep 01, 2026 at 02:39:32PM +0800, Hangbin Liu wrote:

quoted

On Mon, Aug 31, 2026 at 02:16:46PM +0200, Andrew Lunn wrote:

quoted

quoted

 static void nsim_ethtool_ring_init(struct netdevsim *ns)

@@ -250,12 +276,16 @@ void nsim_ethtool_init(struct netdevsim *ns)
 	ns->ethtool.fec.active_fec = ETHTOOL_FEC_NONE;
 
 	ns->ethtool.channels = ns->nsim_bus_dev->num_queues;
+	ns->ethtool.duplex = DUPLEX_FULL;
+	ns->ethtool.speed = SPEED_5000;
 
 	ethtool = debugfs_create_dir("ethtool", ns->nsim_dev_port->ddir);
 	ns->ethtool_ddir = ethtool;
 
 	debugfs_create_u32("get_err", 0600, ethtool, &ns->ethtool.get_err);
 	debugfs_create_u32("set_err", 0600, ethtool, &ns->ethtool.set_err);
+	debugfs_create_u32("speed", 0600, ethtool, &ns->ethtool.speed);
+	debugfs_create_u8("duplex", 0600, ethtool, &ns->ethtool.duplex);

debugfs_create_bool() ?

I'm not sure if anyone want to set nsim duplex to unknown for testing.
Do you think that we should disable this behavior?

Ah, i did not think of DUPLEX_UNKNOWN.

We need to consider Jakubs reply, what are you actually testing here,
do such tests make any sense?

I'm fixing a bug in bonding that need to test with different speed slaves.
So I add this feature for netdevsim.

If they do, i think some validation would be good here. We already
have:

static inline int ethtool_validate_duplex(__u8 duplex)
{
	switch (duplex) {
	case DUPLEX_HALF:
	case DUPLEX_FULL:
	case DUPLEX_UNKNOWN:
		return 1;
	}

	return 0;
}

We don't expect a driver to set duplex to 42, so why should the user
be allowed to do that?

The user interface (ethtool) setting is already handled by
ethtool_virtdev_set_link_ksettings(). Here is the debugfs issue.
Since no one is asking for setting DUPLEX_UNKNOWN, I can use
debugfs_create_bool first.

Also, SPEED_UNKNOWN is -1, so you need debugfs_create_s32().

Ah, yes. Thanks

Hangbin