Ventilator Blues

OK, here's the riff for Ventilator Blues.
It can be played in standard tuning or 5-string open G:
e----------------------
B----------------------
G-----0-0-X-3-X--0---0-
D-----0-0-X-3-X--0-3-0-
A---1------------------
E-3--------------------
d----------------------
B----------------------
G-----0-0-X-3-X--0---0-
D-----0-0-X-3-X--0-3-0-
G-0-3------------------
D----------------------
X = hit strings with right hand
The chords over the chorus part are Gm  - Bb  - F  - C