This is an oxenstored port of the following C xenstored commit:
38eeb3864de40aa568c48f9f26271c141c62b50b tools/xenstored: Drop mapping of the ring via foreign map

Now only Xenctrl.domain_getinfo remains as the last use of unstable xenctrl interface
in oxenstored.

Depends on: tools/ocaml: safer Xenmmap interface
(without it the code would build but the wrong unmap function would get
 called on domain destruction)

CC: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
---
 tools/ocaml/xenstored/domains.ml   | 7 +++++--
 tools/ocaml/xenstored/xenstored.ml | 3 ++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/tools/ocaml/xenstored/domains.ml b/tools/ocaml/xenstored/domains.ml
index 17fe2fa257..d9cb693751 100644
--- a/tools/ocaml/xenstored/domains.ml
+++ b/tools/ocaml/xenstored/domains.ml
@@ -22,6 +22,7 @@ let xc = Xenctrl.interface_open ()
 
 type domains = {
 	eventchn: Event.t;
+	gnttab: Gnt.Gnttab.interface;
 	table: (Xenctrl.domid, Domain.t) Hashtbl.t;
 
 	(* N.B. the Queue module is not thread-safe but oxenstored is single-threaded. *)
@@ -42,8 +43,9 @@ type domains = {
 	mutable n_penalised: int; (* Number of domains with less than maximum credit *)
 }
 
-let init eventchn on_first_conflict_pause = {
+let init eventchn gnttab on_first_conflict_pause = {
 	eventchn = eventchn;
+	gnttab;
 	table = Hashtbl.create 10;
 	doms_conflict_paused = Queue.create ();
 	doms_with_conflict_penalty = Queue.create ();
@@ -123,7 +125,8 @@ let resume _doms _domid =
 	()
 
 let create doms domid mfn port =
-	let interface = Xenctrl.map_foreign_range xc domid (Xenmmap.getpagesize()) mfn in
+	let mapping = Gnt.(Gnttab.map_exn doms.gnttab { domid; ref = xenstore} true) in
+	let interface = Gnt.Gnttab.Local_mapping.to_pages doms.gnttab mapping in
 	let dom = Domain.make domid mfn port interface doms.eventchn in
 	Hashtbl.add doms.table domid dom;
 	Domain.bind_interdomain dom;
diff --git a/tools/ocaml/xenstored/xenstored.ml b/tools/ocaml/xenstored/xenstored.ml
index a6b86b167c..75c35107d5 100644
--- a/tools/ocaml/xenstored/xenstored.ml
+++ b/tools/ocaml/xenstored/xenstored.ml
@@ -446,6 +446,7 @@ let main () =
 
 	let store = Store.create () in
 	let eventchn = Event.init () in
+	let gnttab = Gnt.Gnttab.interface_open () in
 	let next_frequent_ops = ref 0. in
 	let advance_next_frequent_ops () =
 		next_frequent_ops := (Unix.gettimeofday () +. !Define.conflict_max_history_seconds)
@@ -453,7 +454,7 @@ let main () =
 	let delay_next_frequent_ops_by duration =
 		next_frequent_ops := !next_frequent_ops +. duration
 	in
-	let domains = Domains.init eventchn advance_next_frequent_ops in
+	let domains = Domains.init eventchn gnttab advance_next_frequent_ops in
 
 	(* For things that need to be done periodically but more often
 	 * than the periodic_ops function *)
-- 
2.25.1