[Differential] D7185: Add virtio-console support to bhyve

[Paul Vixie]

fwiw, bhyve's existing console support is working fine for me. i use 
rtty (from ports). my configuration looks like this:

[mm1.redbarn:amd64] ls -l /usr/local/rtty/dev
total 3
lrwxr-xr-x  1 root  wheel  11 May 18  2014 family@ -> /dev/nmdm2A
lrwxr-xr-x  1 root  wheel  11 May 17  2014 guests@ -> /dev/nmdm0A
lrwxr-xr-x  1 root  wheel  11 Nov 16  2014 pbx@ -> /dev/nmdm5A
lrwxr-xr-x  1 root  wheel  11 Jun  1  2014 sleipnir@ -> /dev/nmdm3A
lrwxr-xr-x  1 root  wheel  11 May 18  2014 util@ -> /dev/nmdm1A
lrwxr-xr-x  1 root  wheel  11 May  1  2015 yeti-dns@ -> /dev/nmdm7A

the bhyve processes are using the corresponding "B" devices. rtty keeps 
logs:

[mm1.redbarn:amd64] ls -l /usr/local/rtty/log/
total 164401
-rw-r-----  1 root  wheel    2132344 Jul 10 07:18 family
-rw-r-----  1 root  wheel    1176529 Jul 10 03:58 guests
-rw-r-----  1 root  wheel    1964961 Jul 11 06:23 pbx
-rw-r-----  1 root  wheel  133664527 Jul 11 17:25 sleipnir
-rw-r-----  1 root  wheel   17943116 Jul 11 17:06 util
-rw-r-----  1 root  wheel   11042436 Jul 11 17:11 yeti-dns

so i can find out why something crashed even if i wasn't watching at the 
time.

so, i'm having trouble understanding the need for virtio-console to be 
able to open a host-side unix-domain socket in the file system?

vixie (author of rtty)