libxl: make devid a type so it is initialized properly

Previously device ids in libxl were treated as integers meaning they
were being initialized to 0, which is a valid device id. This patch
makes devid its own type in libxl and initializes it to -1, an invalid
value.

This fixes a bug where if you try to do a xl DEV-attach multiple
time it will continuously try to reattach device 0 instead of
generating a new device id.

Signed-off-by: Matthew Fioravante <matthew.fioravante@jhuapl.edu>
Reviewed-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

tools/libxl/gentest.py

@@ -60,7 +60,7 @@ def gen_rand_init(ty, v, indent = "    ", parent = None):
                                         passby=idl.PASS_BY_REFERENCE))
     elif ty.typename in ["libxl_uuid", "libxl_mac", "libxl_hwcap"]:
         s += "rand_bytes((uint8_t *)%s, sizeof(*%s));\n" % (v,v)
-    elif ty.typename in ["libxl_domid"] or isinstance(ty, idl.Number):
+    elif ty.typename in ["libxl_domid", "libxl_devid"] or isinstance(ty, idl.Number):
         s += "%s = rand() %% (sizeof(%s)*8);\n" % \
              (ty.pass_arg(v, parent is None),
               ty.pass_arg(v, parent is None))

tools/libxl/libxl.h

@@ -307,6 +307,7 @@ void libxl_cpuid_dispose(libxl_cpuid_policy_list *cpuid_list);
 #define LIBXL_PCI_FUNC_ALL (~0U)
 
 typedef uint32_t libxl_domid;
+typedef int libxl_devid;
 
 /*
  * Formatting Enumerations.

tools/libxl/libxl_types.idl

@@ -8,6 +8,7 @@ namespace("libxl_")
 libxl_defbool = Builtin("defbool", passby=PASS_BY_REFERENCE)
 
 libxl_domid = Builtin("domid", json_fn = "yajl_gen_integer", autogenerate_json = False)
+libxl_devid = Builtin("devid", json_fn = "yajl_gen_integer", autogenerate_json = False, signed = True, init_val="-1")
 libxl_uuid = Builtin("uuid", passby=PASS_BY_REFERENCE)
 libxl_mac = Builtin("mac", passby=PASS_BY_REFERENCE)
 libxl_bitmap = Builtin("bitmap", dispose_fn="libxl_bitmap_dispose", passby=PASS_BY_REFERENCE)
@@ -337,7 +338,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
 
 libxl_device_vfb = Struct("device_vfb", [
     ("backend_domid", libxl_domid),
-    ("devid",         integer),
+    ("devid",         libxl_devid),
     ("vnc",           libxl_vnc_info),
     ("sdl",           libxl_sdl_info),
     # set keyboard layout, default is en-us keyboard
@@ -346,7 +347,7 @@ libxl_device_vfb = Struct("device_vfb", [
 
 libxl_device_vkb = Struct("device_vkb", [
     ("backend_domid", libxl_domid),
-    ("devid", integer),
+    ("devid", libxl_devid),
     ])
 
 libxl_device_disk = Struct("device_disk", [
@@ -363,7 +364,7 @@ libxl_device_disk = Struct("device_disk", [
 
 libxl_device_nic = Struct("device_nic", [
     ("backend_domid", libxl_domid),
-    ("devid", integer),
+    ("devid", libxl_devid),
     ("mtu", integer),
     ("model", string),
     ("mac", libxl_mac),
@@ -393,7 +394,7 @@ libxl_diskinfo = Struct("diskinfo", [
     ("backend_id", uint32),
     ("frontend", string),
     ("frontend_id", uint32),
-    ("devid", integer),
+    ("devid", libxl_devid),
     ("state", integer),
     ("evtch", integer),
     ("rref", integer),
@@ -404,7 +405,7 @@ libxl_nicinfo = Struct("nicinfo", [
     ("backend_id", uint32),
     ("frontend", string),
     ("frontend_id", uint32),
-    ("devid", integer),
+    ("devid", libxl_devid),
     ("state", integer),
     ("evtch", integer),
     ("rref_tx", integer),

tools/ocaml/libs/xl/genwrap.py

@@ -10,6 +10,7 @@ builtins = {
     "int":                  ("int",                    "%(c)s = Int_val(%(o)s)",            "Val_int(%(c)s)"  ),
     "char *":               ("string",                 "%(c)s = dup_String_val(gc, %(o)s)", "caml_copy_string(%(c)s)"),
     "libxl_domid":          ("domid",                  "%(c)s = Int_val(%(o)s)",            "Val_int(%(c)s)"  ),
+    "libxl_devid":          ("devid",                  "%(c)s = Int_val(%(o)s)",            "Val_int(%(c)s)"  ),
     "libxl_defbool":        ("bool option",            "%(c)s = Defbool_val(%(o)s)",        "Val_defbool(%(c)s)" ),
     "libxl_uuid":           ("int array",              "Uuid_val(gc, lg, &%(c)s, %(o)s)",   "Val_uuid(&%(c)s)"),
     "libxl_key_value_list": ("(string * string) list", None,                                None),
@@ -41,8 +42,8 @@ def stub_fn_name(ty, name):
     return "stub_xl_%s_%s" % (ty.rawname,name)
     
 def ocaml_type_of(ty):
-    if ty.rawname == "domid":
-        return "domid"
+    if ty.rawname in ["domid","devid"]:
+        return ty.rawname
     elif isinstance(ty,idl.UInt):
         if ty.width in [8, 16]:
             # handle as ints

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

@@ -16,6 +16,7 @@
 exception Error of string
 
 type domid = int
+type devid = int
 
 (* @@LIBXL_TYPES@@ *)
 

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

@@ -16,6 +16,7 @@
 exception Error of string
 
 type domid = int
+type devid = int
 
 (* @@LIBXL_TYPES@@ *)
 

tools/python/xen/lowlevel/xl/xl.c

@@ -281,6 +281,11 @@ int attrib__libxl_domid_set(PyObject *v, libxl_domid *domid) {
     return 0;
 }
 
+int attrib__libxl_devid_set(PyObject *v, libxl_devid *devid) {
+   *devid = PyInt_AsLong(v);
+   return 0;
+}
+
 int attrib__struct_in_addr_set(PyObject *v, struct in_addr *pptr)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Setting in_addr");
@@ -342,6 +347,10 @@ PyObject *attrib__libxl_domid_get(libxl_domid *domid) {
     return PyInt_FromLong(*domid);
 }
 
+PyObject *attrib__libxl_devid_get(libxl_devid *devid) {
+    return PyInt_FromLong(*devid);
+}
+
 PyObject *attrib__struct_in_addr_get(struct in_addr *pptr)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Getting in_addr");