Convex optimization with linear constraint?

I'm using PETSc + TAO's LMVM method for a convex optimization problem. As the project progresses, it's clear that some linear constraints are also needed, the problem now looks like: minimize f(vec_x) (f is neither linear or quadratic, but is convex) subject to A * vec_x = vec_b As LMVM does not support linear constraints, I'm looking for another solver. TAO lists several functions dealing with constraints, but they're all in the developer section, and in the samples linked from the manual I haven't found one that's linearly constrained. Is there a suitable one in TAO? Liu Chang