Minimization of the ratio of quadratic forms with constraints

Question

I don't want to re-invent the wheel so I was wondering if anything is known about this problem $$ \begin{equation} \begin{aligned} \min_{x\in\mathbb{R}^d} \quad & \frac{x^\top A x}{x^\top B x} \\ \text{s.t.} \quad & x^\top \mathbf{1} = 1 \\ \text{and } \quad & x \geq 0 \end{aligned} \end{equation} $$ where both $A$ and $B$ are symmetric and positive definite matrices.