  We prove large deviation principles for $\int_0^t \gamma(X_s)ds$, where $X$
is a $d$-dimensional self-similar Gaussian process and $\gamma(x)$ takes the
form of the Dirac delta function $\delta(x)$, $|x|^{-\beta}$ with $\beta\in
(0,d)$, or $\prod_{i=1}^d |x_i|^{-\beta_i}$ with $\beta_i\in(0,1)$. In
particular, large deviations are obtained for the functionals of
$d$-dimensional fractional Brownian motion, sub-fractional Brownian motion and
bi-fractional Brownian motion. As an application, the critical exponential
integrability of the functionals is discussed.
