Using xen host on freebsd, is com1 the only way to attach to dom0?

[Steven Friedrich]

I can boot a xen kernel, but it appears it doesn't acquire a DHCP address
from my router.  Someone suggested using vga=current,keep on xen_cmdline,
but I'm unsure of the valid xen_cmdline arguments.
Do I have to configure and build a FreeBSD kernel or just use what the xen
meta-port builds?
Not having an IP address prevents use of VNC viewer...