libxl: ocaml: add VM lifecycle operations

Also:
* Reorganise toplevel OCaml functions into modules of Xenlight.
* Factor out the management of ao_how into the function aohow_val. The ao_how
  is now malloc'ed, just to make this function a little easier to use.

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: David Scott <dave.scott@eu.citrix.com>

tools/ocaml/libs/xl/xenlight.ml.in

@@ -33,9 +33,24 @@ type event =
 	| POLLHUP (* Device has been disconnected (revents only) *)
 	| POLLNVAL (* Invalid request: fd not open (revents only). *)
 
-external send_trigger : ctx -> domid -> trigger -> int -> unit = "stub_xl_send_trigger"
-external send_sysrq : ctx -> domid -> char -> unit = "stub_xl_send_sysrq"
-external send_debug_keys : ctx -> string -> unit = "stub_xl_send_debug_keys"
+module Domain = struct
+	external create_new : ctx -> Domain_config.t -> ?async:'a -> unit -> domid = "stub_libxl_domain_create_new"
+	external create_restore : ctx -> Domain_config.t -> (Unix.file_descr * Domain_restore_params.t) ->
+		?async:'a -> unit -> domid = "stub_libxl_domain_create_restore"
+	external shutdown : ctx -> domid -> unit = "stub_libxl_domain_shutdown"
+	external reboot : ctx -> domid -> unit = "stub_libxl_domain_reboot"
+	external destroy : ctx -> domid -> ?async:'a -> unit -> unit = "stub_libxl_domain_destroy"
+	external suspend : ctx -> domid -> Unix.file_descr -> ?async:'a -> unit -> unit = "stub_libxl_domain_suspend"
+	external pause : ctx -> domid -> unit = "stub_libxl_domain_pause"
+	external unpause : ctx -> domid -> unit = "stub_libxl_domain_unpause"
+
+	external send_trigger : ctx -> domid -> trigger -> int -> unit = "stub_xl_send_trigger"
+	external send_sysrq : ctx -> domid -> char -> unit = "stub_xl_send_sysrq"
+end
+
+module Host = struct
+	external send_debug_keys : ctx -> string -> unit = "stub_xl_send_debug_keys"
+end
 
 module Async = struct
 	type for_libxl

tools/ocaml/libs/xl/xenlight.mli.in

@@ -35,9 +35,24 @@ type event =
 	| POLLHUP (* Device has been disconnected (revents only) *)
 	| POLLNVAL (* Invalid request: fd not open (revents only). *)
 
-external send_trigger : ctx -> domid -> trigger -> int -> unit = "stub_xl_send_trigger"
-external send_sysrq : ctx -> domid -> char -> unit = "stub_xl_send_sysrq"
-external send_debug_keys : ctx -> string -> unit = "stub_xl_send_debug_keys"
+module Domain : sig
+	external create_new : ctx -> Domain_config.t -> ?async:'a -> unit -> domid = "stub_libxl_domain_create_new"
+	external create_restore : ctx -> Domain_config.t -> (Unix.file_descr * Domain_restore_params.t) ->
+		?async:'a -> unit -> domid = "stub_libxl_domain_create_restore"
+	external shutdown : ctx -> domid -> unit = "stub_libxl_domain_shutdown"
+	external reboot : ctx -> domid -> unit = "stub_libxl_domain_reboot"
+	external destroy : ctx -> domid -> ?async:'a -> unit -> unit = "stub_libxl_domain_destroy"
+	external suspend : ctx -> domid -> Unix.file_descr -> ?async:'a -> unit -> unit = "stub_libxl_domain_suspend"
+	external pause : ctx -> domid -> unit = "stub_libxl_domain_pause"
+	external unpause : ctx -> domid -> unit = "stub_libxl_domain_unpause"
+
+	external send_trigger : ctx -> domid -> trigger -> int -> unit = "stub_xl_send_trigger"
+	external send_sysrq : ctx -> domid -> char -> unit = "stub_xl_send_sysrq"
+end
+
+module Host : sig
+	external send_debug_keys : ctx -> string -> unit = "stub_xl_send_debug_keys"
+end
 
 module Async : sig
 	type for_libxl

tools/ocaml/libs/xl/xenlight_stubs.c

@@ -401,6 +401,168 @@ void async_callback(libxl_ctx *ctx, int rc, void *for_callback)
 	free(p);
 }
 
+static libxl_asyncop_how *aohow_val(value async, libxl_asyncop_how *ao_how)
+{
+	CAMLparam1(async);
+	value *p;
+
+	if (async != Val_none) {
+		/* for_callback must be a pointer to a "value" that is malloc'ed and
+		 * registered with the OCaml GC. This ensures that the GC does not remove
+		 * the corresponding OCaml heap blocks, and allows the GC to update the value
+		 * when blocks are moved around, while libxl is free to copy the pointer if
+		 * it needs to.
+		 * The for_callback pointer must always be non-NULL. */
+		p = malloc(sizeof(value));
+		if (!p)
+			failwith_xl(ERROR_NOMEM, "cannot allocate value");
+		*p = Some_val(async);
+		caml_register_global_root(p);
+		ao_how->callback = async_callback;
+		ao_how->u.for_callback = (void *) p;
+		CAMLreturnT(libxl_asyncop_how *, ao_how);
+	}
+	else
+		CAMLreturnT(libxl_asyncop_how *, NULL);
+}
+
+value stub_libxl_domain_create_new(value ctx, value domain_config, value async, value unit)
+{
+	CAMLparam4(ctx, async, domain_config, unit);
+	int ret;
+	libxl_domain_config c_dconfig;
+	uint32_t c_domid;
+	libxl_asyncop_how ao_how;
+
+	libxl_domain_config_init(&c_dconfig);
+	ret = domain_config_val(CTX, &c_dconfig, domain_config);
+	if (ret != 0) {
+		libxl_domain_config_dispose(&c_dconfig);
+		failwith_xl(ret, "domain_create_new");
+	}
+
+	ret = libxl_domain_create_new(CTX, &c_dconfig, &c_domid,
+		aohow_val(async, &ao_how), NULL);
+
+	libxl_domain_config_dispose(&c_dconfig);
+
+	if (ret != 0)
+		failwith_xl(ret, "domain_create_new");
+
+	CAMLreturn(Val_int(c_domid));
+}
+
+value stub_libxl_domain_create_restore(value ctx, value domain_config, value params,
+	value async, value unit)
+{
+	CAMLparam5(ctx, domain_config, params, async, unit);
+	int ret;
+	libxl_domain_config c_dconfig;
+	libxl_domain_restore_params c_params;
+	uint32_t c_domid;
+	libxl_asyncop_how ao_how;
+
+	libxl_domain_config_init(&c_dconfig);
+	ret = domain_config_val(CTX, &c_dconfig, domain_config);
+	if (ret != 0) {
+		libxl_domain_config_dispose(&c_dconfig);
+		failwith_xl(ret, "domain_create_restore");
+	}
+
+	libxl_domain_restore_params_init(&c_params);
+	ret = domain_restore_params_val(CTX, &c_params, Field(params, 1));
+	if (ret != 0) {
+		libxl_domain_restore_params_dispose(&c_params);
+		failwith_xl(ret, "domain_create_restore");
+	}
+
+	ret = libxl_domain_create_restore(CTX, &c_dconfig, &c_domid, Int_val(Field(params, 0)),
+		&c_params, aohow_val(async, &ao_how), NULL);
+
+	libxl_domain_config_dispose(&c_dconfig);
+	libxl_domain_restore_params_dispose(&c_params);
+
+	if (ret != 0)
+		failwith_xl(ret, "domain_create_restore");
+
+	CAMLreturn(Val_int(c_domid));
+}
+
+value stub_libxl_domain_shutdown(value ctx, value domid)
+{
+	CAMLparam2(ctx, domid);
+	int ret;
+
+	ret = libxl_domain_shutdown(CTX, Int_val(domid));
+	if (ret != 0)
+		failwith_xl(ret, "domain_shutdown");
+
+	CAMLreturn(Val_unit);
+}
+
+value stub_libxl_domain_reboot(value ctx, value domid)
+{
+	CAMLparam2(ctx, domid);
+	int ret;
+
+	ret = libxl_domain_reboot(CTX, Int_val(domid));
+	if (ret != 0)
+		failwith_xl(ret, "domain_reboot");
+
+	CAMLreturn(Val_unit);
+}
+
+value stub_libxl_domain_destroy(value ctx, value domid, value async, value unit)
+{
+	CAMLparam4(ctx, domid, async, unit);
+	int ret;
+	libxl_asyncop_how ao_how;
+
+	ret = libxl_domain_destroy(CTX, Int_val(domid), aohow_val(async, &ao_how));
+	if (ret != 0)
+		failwith_xl(ret, "domain_destroy");
+
+	CAMLreturn(Val_unit);
+}
+
+value stub_libxl_domain_suspend(value ctx, value domid, value fd, value async, value unit)
+{
+	CAMLparam5(ctx, domid, fd, async, unit);
+	int ret;
+	libxl_asyncop_how ao_how;
+
+	ret = libxl_domain_suspend(CTX, Int_val(domid), Int_val(fd), 0,
+		aohow_val(async, &ao_how));
+	if (ret != 0)
+		failwith_xl(ret, "domain_suspend");
+
+	CAMLreturn(Val_unit);
+}
+
+value stub_libxl_domain_pause(value ctx, value domid)
+{
+	CAMLparam2(ctx, domid);
+	int ret;
+
+	ret = libxl_domain_pause(CTX, Int_val(domid));
+	if (ret != 0)
+		failwith_xl(ret, "domain_pause");
+
+	CAMLreturn(Val_unit);
+}
+
+value stub_libxl_domain_unpause(value ctx, value domid)
+{
+	CAMLparam2(ctx, domid);
+	int ret;
+
+	ret = libxl_domain_unpause(CTX, Int_val(domid));
+	if (ret != 0)
+		failwith_xl(ret, "domain_unpause");
+
+	CAMLreturn(Val_unit);
+}
+
 #define _STRINGIFY(x) #x
 #define STRINGIFY(x) _STRINGIFY(x)
 
@@ -412,20 +574,11 @@ value stub_xl_device_##type##_##op(value ctx, value info, value domid,	\
 	libxl_device_##type c_info;					\
 	int ret, marker_var;						\
 	libxl_asyncop_how ao_how;					\
-	value *p;							\
 									\
 	device_##type##_val(CTX, &c_info, info);			\
 									\
-	if (async != Val_none) {					\
-		p = malloc(sizeof(value));				\
-		*p = Some_val(async);					\
-		caml_register_global_root(p);				\
-		ao_how.callback = async_callback;			\
-		ao_how.u.for_callback = (void *) p;			\
-	}								\
-									\
 	ret = libxl_##fn##_##op(CTX, Int_val(domid), &c_info,		\
-		async != Val_none ? &ao_how : NULL);			\
+		aohow_val(async, &ao_how));				\
 									\
 	libxl_device_##type##_dispose(&c_info);				\
 									\

tools/ocaml/test/send_debug_keys.ml

@@ -4,7 +4,7 @@ open Xenlight
 
 let send_keys ctx s =
   printf "Sending debug key %s\n" s;
-  Xenlight.send_debug_keys ctx s;
+  Xenlight.Host.send_debug_keys ctx s;
   ()
   
 let _ =