brand/bhyve: Add comN attribute

src/brand/bhyve/boot.py

@@ -450,6 +450,12 @@ def apply_bootnext(v):
 
 args.extend(['-s', '{0},lpc'.format(LPC_SLOT)])
 
+# LPC Serial Ports
+
+for i, v in z.build_devlist('com', 4):
+    if i > 1:
+        args.extend(['-l', 'com{0},{1}'.format(i, v)])
+
 # Console
 
 args.extend(['-l', 'com1,{0}'.format(opts['console'])])

src/man/bhyve.7

@@ -225,6 +225,35 @@ If a
 .Ar URL
 is provided, then that is passed to the guest system as the source of the
 full meta-data.
+.\" com
+.It Ic com Ns Ar N Ar options
+.Pp
+This parameter configures a LPC COM port, with valid values for
+.Ar N
+ranging from 2 to 4.
+.Pp
+The supported
+.Ar options
+are either
+.Cm socket , Ns Ar path ,
+which places a UNIX domain socket at
+.Ar path ,
+or
+.Pa /dev/ttyXX ,
+which attaches the COM port to a
+.Sy tty
+device.
+The latter format requires a
+.Sy device
+block to map
+.Pa /dev/ttyXX
+into the zone.
+.Pp
+A configuration for
+.Ic com Ns Ar 1
+will be silently ignored, the
+.Ic console
+parameter described below must be used instead.
 .\" console
 .It Ic console Ar options
 .Pp