He's performing well in that holding midfielder role but I don't see a 'Xavi' in him. He's in his ideal conditions now for RM, spraying passes from a deep position without having to contend with much pressure or have creative duties.
He can make some passes between the lines but he needs a lot of time and can't stand that much pressure, anything more than one man coming from one direction and he suffers. Playing exclusively behind the opposition's defensive mass benefits him as he doesn't have to contend with the difficulty of tight spaces. His long balls and set piece deliveries are his strongest points. Spreading the ball and keeping it moving pretty much defines his role at Real. Defensively I'm not at all impressed, makes a lot of sloppy fouls and has wayward positioning at times.
All in all, he's basically on the same wavelength of a player as Rakitic except with tidier passing and less mobility. I could see Rakitic performing his role at Madrid with the same level of success and probably better defensively too since they have the same qualities and faults (great long-balls and ability to spread passes wide but poor vision, agility, and struggle under pressure).
Xavi is much more of a playmaker than either of the two. Creating space and combining with all of his teammates in the bulk of the midfield, not behind the pressure. He takes a large responsibility for chance creation and that's why the likes of Gundogan/Koke/Modric are closer to his role.