vl: add -object option to create QOM objects from the command line

This will create a new QOM object in the '/objects' path.  Note that properties
are set in order which allows for simple objects to be initialized entirely
with this option and then realized.

This option is roughly equivalent to -device but for things that are not
devices.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

qemu-config.c

@@ -682,6 +682,15 @@ static QemuOptsList qemu_add_fd_opts = {
     },
 };
 
+static QemuOptsList qemu_object_opts = {
+    .name = "object",
+    .implied_opt_name = "qom-type",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
+    .desc = {
+        { }
+    },
+};
+
 static QemuOptsList *vm_config_groups[32] = {
     &qemu_drive_opts,
     &qemu_chardev_opts,
@@ -699,6 +708,7 @@ static QemuOptsList *vm_config_groups[32] = {
     &qemu_iscsi_opts,
     &qemu_sandbox_opts,
     &qemu_add_fd_opts,
+    &qemu_object_opts,
     NULL,
 };
 

qemu-options.hx

@@ -2904,6 +2904,14 @@ DEF("no-kvm-irqchip", HAS_ARG, QEMU_OPTION_no_kvm_irqchip, "", QEMU_ARCH_I386)
 HXCOMM Deprecated (ignored)
 DEF("tdf", 0, QEMU_OPTION_tdf,"", QEMU_ARCH_ALL)
 
+DEF("object", HAS_ARG, QEMU_OPTION_object,
+    "-object TYPENAME[,PROP1=VALUE1,...]\n"
+    "                create an new object of type TYPENAME setting properties\n"
+    "                in the order they are specified.  Note that the 'id'\n"
+    "                property must be set.  These objects are placed in the\n"
+    "                '/objects' path.\n",
+    QEMU_ARCH_ALL)
+
 HXCOMM This is the last statement. Insert new options before this line!
 STEXI
 @end table

vl.c

@@ -168,6 +168,7 @@ int main(int argc, char **argv)
 #include "osdep.h"
 
 #include "ui/qemu-spice.h"
+#include "qapi/string-input-visitor.h"
 
 //#define DEBUG_NET
 //#define DEBUG_SLIRP
@@ -2476,6 +2477,53 @@ static void free_and_trace(gpointer mem)
     free(mem);
 }
 
+static int object_set_property(const char *name, const char *value, void *opaque)
+{
+    Object *obj = OBJECT(opaque);
+    StringInputVisitor *siv;
+    Error *local_err = NULL;
+
+    if (strcmp(name, "qom-type") == 0 || strcmp(name, "id") == 0) {
+        return 0;
+    }
+
+    siv = string_input_visitor_new(value);
+    object_property_set(obj, string_input_get_visitor(siv), name, &local_err);
+    string_input_visitor_cleanup(siv);
+
+    if (local_err) {
+        qerror_report_err(local_err);
+        error_free(local_err);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int object_create(QemuOpts *opts, void *opaque)
+{
+    const char *type = qemu_opt_get(opts, "qom-type");
+    const char *id = qemu_opts_id(opts);
+    Object *obj;
+
+    g_assert(type != NULL);
+
+    if (id == NULL) {
+        qerror_report(QERR_MISSING_PARAMETER, "id");
+        return -1;
+    }
+
+    obj = object_new(type);
+    if (qemu_opt_foreach(opts, object_set_property, obj, 1) < 0) {
+        return -1;
+    }
+
+    object_property_add_child(container_get(object_get_root(), "/objects"),
+                              id, obj, NULL);
+
+    return 0;
+}
+
 int main(int argc, char **argv, char **envp)
 {
     int i;
@@ -3473,6 +3521,9 @@ int main(int argc, char **argv, char **envp)
                 exit(1);
 #endif
                 break;
+            case QEMU_OPTION_object:
+                opts = qemu_opts_parse(qemu_find_opts("object"), optarg, 1);
+                break;
             default:
                 os_parse_cmd_args(popt->index, optarg);
             }
@@ -3508,6 +3559,11 @@ int main(int argc, char **argv, char **envp)
         qemu_set_version(machine->hw_version);
     }
 
+    if (qemu_opts_foreach(qemu_find_opts("object"),
+                          object_create, NULL, 0) != 0) {
+        exit(1);
+    }
+
     /* Init CPU def lists, based on config
      * - Must be called after all the qemu_read_config_file() calls
      * - Must be called before list_cpus()