need explanation about definitions

I would like to solve a linear equation using cuSparse API.
The function I would like to use is “cusolverStatus_t cusolverSpZcsrluSolveHost

What does [Host] means?
What does “Remark 1: only CPU path is provided” means?

It is unclear to me as this API provide function that uses GPU.

Any assistance will be highly appreciated!

Thanks!