I want to solve a semi-definite problem with CVX

I have some pairs of similar points in a set called S

and some pairs of dissimilar points in a set called D

And I want to find a symmetric positive semi definite matrix by solving problem in below:

min_ A ∑_((x_i,x_j∈S)) ‖x_i-x_j ‖_A^2

s.t ∑_((x_i,x_j∈D)) ‖x_i-x_j ‖_A >= 1

A>=0

where ‖x_i-x_j ‖_A = √((x-y)^T A (x-y))

but I don’t know how to write it in a format that can be solved by CVX