Obtain a periodic convolution matrix for 2D signal

Following matlab code generates a periodic convolution matrix for 1D case. Can somebody tell me the way to generate the matrix for 2D case?

In the following, s is a 1D signal and g is a 1D kernel. I want to generate the convolution matrix when s is a 2D signal.

 %h=ifft(fft(s).*fft(g));
 h_mat=ifft(fft(eye(length(s))).*fft(g));
 %h1 = h_mat*s;