How can I pass an interfaec{} instance to a function that expects a struct pointer?

The GORM library has us perform queries by passing pointers to structs that are mapped to database tables, for instance: db.First(&user). In doing so, the First function fills all of user's fields with the data it fetches from the underlying database.

Now suppose we have a function that receives an interface{} parameter that is guaranteed to correspond to a valid ORM struct, for instance:

func (crud DbCRUD) Read(r interface{}) error {
    return crud.db.First(r).Error
}

This particular function fails with a unsupported destination, should be slice or struct message, coming from gorm.Query. The error seems to relate to the fact that gorm.Query expects a slice or a struct, and is instead receiving an interface{}.

My question is therefore the following: how can I obtain a pointer to the struct underlying r in the above function, such that it can be passed to gorm.DB.First?

Intuitively, it would seem that the reflect package is involved, but I'm having trouble stringing the pieces together.