[PATCH v1 4/4] tools/ocaml/libs/xc: backward compatible domid control at domain creation time

[Edwin Török <edvin.torok@xxxxxxxxxx>]

One can specify the domid to use when creating the domain, but this was 
hardcoded to 0.

Keep the existing `domain_create` function (and the type of its parameters) as 
is to make
backwards compatibility easier.
Introduce a new `domain_create_domid` OCaml API that allows specifying the 
domid.
A new version of xenopsd can choose to start using this, while old versions of 
xenopsd will keep
building and using the old API.

Controlling the domid can be useful during testing or migration.

Signed-off-by: Edwin Török <edvin.torok@xxxxxxxxxx>
---
 tools/ocaml/libs/xc/xenctrl.ml      | 3 +++
 tools/ocaml/libs/xc/xenctrl.mli     | 2 ++
 tools/ocaml/libs/xc/xenctrl_stubs.c | 9 +++++++--
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/tools/ocaml/libs/xc/xenctrl.ml b/tools/ocaml/libs/xc/xenctrl.ml
index e878699b0a..9d720886e9 100644
--- a/tools/ocaml/libs/xc/xenctrl.ml
+++ b/tools/ocaml/libs/xc/xenctrl.ml
@@ -182,6 +182,9 @@ let with_intf f =
 external domain_create: handle -> domctl_create_config -> domid
        = "stub_xc_domain_create"
 
+external domain_create_domid: handle -> domctl_create_config -> domid -> domid
+       = "stub_xc_domain_create_domid"
+
 external domain_sethandle: handle -> domid -> string -> unit
        = "stub_xc_domain_sethandle"
 
diff --git a/tools/ocaml/libs/xc/xenctrl.mli b/tools/ocaml/libs/xc/xenctrl.mli
index e64907df8e..e629022901 100644
--- a/tools/ocaml/libs/xc/xenctrl.mli
+++ b/tools/ocaml/libs/xc/xenctrl.mli
@@ -145,6 +145,8 @@ val close_handle: unit -> unit
 
 external domain_create : handle -> domctl_create_config -> domid
   = "stub_xc_domain_create"
+external domain_create_domid : handle -> domctl_create_config -> domid -> domid
+  = "stub_xc_domain_create_domid"
 external domain_sethandle : handle -> domid -> string -> unit = 
"stub_xc_domain_sethandle"
 external domain_max_vcpus : handle -> domid -> int -> unit
   = "stub_xc_domain_max_vcpus"
diff --git a/tools/ocaml/libs/xc/xenctrl_stubs.c 
b/tools/ocaml/libs/xc/xenctrl_stubs.c
index 94aba38a42..bb718fd164 100644
--- a/tools/ocaml/libs/xc/xenctrl_stubs.c
+++ b/tools/ocaml/libs/xc/xenctrl_stubs.c
@@ -175,7 +175,7 @@ static unsigned int ocaml_list_to_c_bitmap(value l)
        return val;
 }
 
-CAMLprim value stub_xc_domain_create(value xch, value config)
+CAMLprim value stub_xc_domain_create_domid(value xch, value config, value 
want_domid)
 {
        CAMLparam2(xch, config);
        CAMLlocal2(l, arch_domconfig);
@@ -191,7 +191,7 @@ CAMLprim value stub_xc_domain_create(value xch, value 
config)
 #define VAL_MAX_MAPTRACK_FRAMES Field(config, 7)
 #define VAL_ARCH                Field(config, 8)
 
-       uint32_t domid = 0;
+       uint32_t domid = Int_val(want_domid);
        int result;
        struct xen_domctl_createdomain cfg = {
                .ssidref = Int32_val(VAL_SSIDREF),
@@ -262,6 +262,11 @@ CAMLprim value stub_xc_domain_create(value xch, value 
config)
        CAMLreturn(Val_int(domid));
 }
 
+CAMLprim value stub_xc_domain_create(value xch, value config, value want_domid)
+{
+    return stub_xc_domain_create_domid(xch, config, Val_int(0));
+}
+
 CAMLprim value stub_xc_domain_max_vcpus(value xch, value domid,
                                         value max_vcpus)
 {
-- 
2.18.4