wpa_supplicant error on mac

[Gua Chung Lim <ptkrisada%gmail.com@localhost>]

Hi,

I'm running NetBSD 7.1_STABLE as a guest behind VirtualBox.
My machine is MacBook Air 11" mid 2013 running macOS Sierra 10.12.5 as a host.
I set VM network to bridge and login WPA2 (my local wifi network).
I'm not sure if NetBSD 7.1 fully supports Mac's NIC.
wm0 is for connecting outside world, while wm1 is for connecting only host OS.
During boot I notice an error on wm0.

...
Starting wpa_supplicant.
Successfully initialized wpa_supplicant
iwm0: Failed to initialize driver interface
/etc/rc.d/wpa_supplicant exited with code 1
Starting dhcpcd.
...

But I can use wm0 pretty fine both IPv4 and IPv6.
I'm curious to know what this error means and how to fix it.
I have these relevant lines in configuration files.

/etc/rc.conf
...
wpa_supplicant=YES
wpa_supplicant_flags="-i iwm0 -c /etc/wpa_supplicant.conf"
ip6mode="autohost"
dhcpcd=YES
dhcpcd_flags="-b"
# ifconfig_wm0=dhcp
ifconfig_wm1="inet 192.168.56.56 netmask 0xffffff00"
...

% cat /etc/wpa_supplicant.conf
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
update_config=1

network={
	ssid="MyLocalWiFi"
	psk="MyPassphrase"
}

% cat /etc/ifconfig.wm0
up
!rtsol $int

% ifconfig wm0
wm0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	capabilities=2bf80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx>
	capabilities=2bf80<TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Tx>
	capabilities=2bf80<UDP6CSUM_Tx>
	enabled=0
	ec_capabilities=7<VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU>
	ec_enabled=0
	address: 08:00:27:af:97:e5
	media: Ethernet autoselect (1000baseT full-duplex)
	status: active
	inet 192.168.1.107 netmask 0xffffff00 broadcast 192.168.1.255
	inet6 fe80::a00:27ff:feaf:97e5%wm0 prefixlen 64 scopeid 0x1
	inet6 2405:9800:b4c0:228b:a00:27ff:feaf:97e5 prefixlen 64 autoconf
	inet6 2405:9800:b4c0:228b:6dc5:adb9:c4e8:d0fe prefixlen 64

Please someone point me out.
Thank you in advance.

-- 
Gua Chung Lim
 
If you desire knowledges, learn one thing everyday.
If you desire wisdom, leave one thing everyday.
 
-- Lao Tzu