I think that it would be useful to add a "vgstack" script. This would work like pstack/gstack but rather than print the host stack it would print the guest stack.

gstack does this

$GDB --quiet -nx $GDBARGS /proc/$1/exe $1 <<EOF 2>&1 | 
set width 0
set height 0
set pagination no
$backtrace
EOF
/bin/sed -n \
    -e 's/^\((gdb) \)*//' \
    -e '/^#/p' \
    -e '/^Thread/p'

If I move the exe and pid and put in a vgdb command like this

$GDB --quiet -nx $GDBARGS <<EOF 2>&1 |
set width 0
set height 0
set pagination no
target remote | vgdb --pid=$1
$backtrace
EOF
/bin/sed -n \
    -e 's/^\((gdb) \)*//' \
    -e '/^#/p' \
    -e '/^Thread/p'

then it seems to work reasonably well.

I'll need to adapt it so that it works on FreeBSD (and maybe illumos).