qdev: Base object creation on QDict rather than QemuOpts

QDicts are both what QMP natively uses and what the keyval parser
produces. Going through QemuOpts isn't useful for either one, so switch
the main device creation function to QDicts. By sharing more code with
the -object/object-add code path, we can even reduce the code size a
bit.

This commit doesn't remove the detour through QemuOpts from any code
path yet, but it allows the following commits to do so.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20211008133442.141332-15-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

hw/core/qdev.c

@@ -28,6 +28,7 @@
 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "qapi/qapi-events-qdev.h"
+#include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qerror.h"
 #include "qapi/visitor.h"
 #include "qemu/error-report.h"
@@ -211,14 +212,14 @@ void device_listener_unregister(DeviceListener *listener)
     QTAILQ_REMOVE(&device_listeners, listener, link);
 }
 
-bool qdev_should_hide_device(QemuOpts *opts, Error **errp)
+bool qdev_should_hide_device(const QDict *opts, bool from_json, Error **errp)
 {
     ERRP_GUARD();
     DeviceListener *listener;
 
     QTAILQ_FOREACH(listener, &device_listeners, link) {
         if (listener->hide_device) {
-            if (listener->hide_device(listener, opts, errp)) {
+            if (listener->hide_device(listener, opts, from_json, errp)) {
                 return true;
             } else if (*errp) {
                 return false;
@@ -958,7 +959,7 @@ static void device_finalize(Object *obj)
         dev->canonical_path = NULL;
     }
 
-    qemu_opts_del(dev->opts);
+    qobject_unref(dev->opts);
     g_free(dev->id);
 }
 

hw/net/virtio-net.c

@@ -858,9 +858,11 @@ static void failover_add_primary(VirtIONet *n, Error **errp)
         return;
     }
 
-    dev = qdev_device_add(n->primary_opts, &err);
+    dev = qdev_device_add_from_qdict(n->primary_opts,
+                                     n->primary_opts_from_json,
+                                     &err);
     if (err) {
-        qemu_opts_del(n->primary_opts);
+        qobject_unref(n->primary_opts);
         n->primary_opts = NULL;
     } else {
         object_unref(OBJECT(dev));
@@ -3287,7 +3289,9 @@ static void virtio_net_migration_state_notifier(Notifier *notifier, void *data)
 }
 
 static bool failover_hide_primary_device(DeviceListener *listener,
-                                         QemuOpts *device_opts, Error **errp)
+                                         const QDict *device_opts,
+                                         bool from_json,
+                                         Error **errp)
 {
     VirtIONet *n = container_of(listener, VirtIONet, primary_listener);
     const char *standby_id;
@@ -3295,7 +3299,7 @@ static bool failover_hide_primary_device(DeviceListener *listener,
     if (!device_opts) {
         return false;
     }
-    standby_id = qemu_opt_get(device_opts, "failover_pair_id");
+    standby_id = qdict_get_try_str(device_opts, "failover_pair_id");
     if (g_strcmp0(standby_id, n->netclient_name) != 0) {
         return false;
     }
@@ -3306,12 +3310,8 @@ static bool failover_hide_primary_device(DeviceListener *listener,
         return false;
     }
 
-    /*
-     * Having a weak reference here should be okay because a device can't be
-     * deleted while it's hidden. This will be replaced soon with a QDict that
-     * has a clearer ownership model.
-     */
-    n->primary_opts = device_opts;
+    n->primary_opts = qdict_clone_shallow(device_opts);
+    n->primary_opts_from_json = from_json;
 
     /* failover_primary_hidden is set during feature negotiation */
     return qatomic_read(&n->failover_primary_hidden);
@@ -3502,8 +3502,11 @@ static void virtio_net_device_unrealize(DeviceState *dev)
     g_free(n->vlans);
 
     if (n->failover) {
+        qobject_unref(n->primary_opts);
         device_listener_unregister(&n->primary_listener);
         remove_migration_state_change_notifier(&n->migration_state);
+    } else {
+        assert(n->primary_opts == NULL);
     }
 
     max_queues = n->multiqueue ? n->max_queues : 1;

hw/vfio/pci.c

@@ -29,10 +29,10 @@
 #include "hw/qdev-properties.h"
 #include "hw/qdev-properties-system.h"
 #include "migration/vmstate.h"
+#include "qapi/qmp/qdict.h"
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
 #include "qemu/module.h"
-#include "qemu/option.h"
 #include "qemu/range.h"
 #include "qemu/units.h"
 #include "sysemu/kvm.h"
@@ -941,7 +941,7 @@ static void vfio_pci_size_rom(VFIOPCIDevice *vdev)
     }
 
     if (vfio_opt_rom_in_denylist(vdev)) {
-        if (dev->opts && qemu_opt_get(dev->opts, "rombar")) {
+        if (dev->opts && qdict_haskey(dev->opts, "rombar")) {
             warn_report("Device at %s is known to cause system instability"
                         " issues during option rom execution",
                         vdev->vbasedev.name);

include/hw/qdev-core.h

@@ -180,7 +180,7 @@ struct DeviceState {
     char *canonical_path;
     bool realized;
     bool pending_deleted_event;
-    QemuOpts *opts;
+    QDict *opts;
     int hotplugged;
     bool allow_unplug_during_migration;
     BusState *parent_bus;
@@ -205,8 +205,8 @@ struct DeviceListener {
      * On errors, it returns false and errp is set. Device creation
      * should fail in this case.
      */
-    bool (*hide_device)(DeviceListener *listener, QemuOpts *device_opts,
-                        Error **errp);
+    bool (*hide_device)(DeviceListener *listener, const QDict *device_opts,
+                        bool from_json, Error **errp);
     QTAILQ_ENTRY(DeviceListener) link;
 };
 
@@ -835,13 +835,15 @@ void device_listener_unregister(DeviceListener *listener);
 
 /**
  * @qdev_should_hide_device:
- * @opts: QemuOpts as passed on cmdline.
+ * @opts: options QDict
+ * @from_json: true if @opts entries are typed, false for all strings
+ * @errp: pointer to error object
  *
  * Check if a device should be added.
  * When a device is added via qdev_device_add() this will be called,
  * and return if the device should be added now or not.
  */
-bool qdev_should_hide_device(QemuOpts *opts, Error **errp);
+bool qdev_should_hide_device(const QDict *opts, bool from_json, Error **errp);
 
 typedef enum MachineInitPhase {
     /* current_machine is NULL.  */

include/hw/virtio/virtio-net.h

@@ -209,7 +209,8 @@ struct VirtIONet {
     bool failover_primary_hidden;
     bool failover;
     DeviceListener primary_listener;
-    QemuOpts *primary_opts;
+    QDict *primary_opts;
+    bool primary_opts_from_json;
     Notifier migration_state;
     VirtioNetRssData rss_data;
     struct NetRxPkt *rx_pkt;

include/monitor/qdev.h

@@ -9,6 +9,8 @@ void qmp_device_add(QDict *qdict, QObject **ret_data, Error **errp);
 
 int qdev_device_help(QemuOpts *opts);
 DeviceState *qdev_device_add(QemuOpts *opts, Error **errp);
+DeviceState *qdev_device_add_from_qdict(const QDict *opts,
+                                        bool from_json, Error **errp);
 
 /**
  * qdev_set_id: parent the device and set its id if provided.

softmmu/qdev-monitor.c

@@ -196,34 +196,6 @@ static void qdev_print_devinfos(bool show_no_user)
     g_slist_free(list);
 }
 
-static int set_property(void *opaque, const char *name, const char *value,
-                        Error **errp)
-{
-    Object *obj = opaque;
-    QString *val;
-    Visitor *v;
-    int ret;
-
-    if (strcmp(name, "driver") == 0)
-        return 0;
-    if (strcmp(name, "bus") == 0)
-        return 0;
-
-    val = qstring_from_str(value);
-    v = qobject_input_visitor_new_keyval(QOBJECT(val));
-
-    if (!object_property_set(obj, name, v, errp)) {
-        ret = -1;
-        goto out;
-    }
-
-    ret = 0;
-out:
-    visit_free(v);
-    qobject_unref(val);
-    return ret;
-}
-
 static const char *find_typename_by_alias(const char *alias)
 {
     int i;
@@ -624,15 +596,17 @@ const char *qdev_set_id(DeviceState *dev, char *id, Error **errp)
     return prop->name;
 }
 
-DeviceState *qdev_device_add(QemuOpts *opts, Error **errp)
+DeviceState *qdev_device_add_from_qdict(const QDict *opts,
+                                        bool from_json, Error **errp)
 {
     ERRP_GUARD();
     DeviceClass *dc;
     const char *driver, *path;
+    char *id;
     DeviceState *dev = NULL;
     BusState *bus = NULL;
 
-    driver = qemu_opt_get(opts, "driver");
+    driver = qdict_get_try_str(opts, "driver");
     if (!driver) {
         error_setg(errp, QERR_MISSING_PARAMETER, "driver");
         return NULL;
@@ -645,7 +619,7 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp)
     }
 
     /* find bus */
-    path = qemu_opt_get(opts, "bus");
+    path = qdict_get_try_str(opts, "bus");
     if (path != NULL) {
         bus = qbus_find(path, errp);
         if (!bus) {
@@ -665,12 +639,12 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp)
         }
     }
 
-    if (qemu_opt_get(opts, "failover_pair_id")) {
-        if (!opts->id) {
+    if (qdict_haskey(opts, "failover_pair_id")) {
+        if (!qdict_haskey(opts, "id")) {
             error_setg(errp, "Device with failover_pair_id don't have id");
             return NULL;
         }
-        if (qdev_should_hide_device(opts, errp)) {
+        if (qdev_should_hide_device(opts, from_json, errp)) {
             if (bus && !qbus_is_hotpluggable(bus)) {
                 error_setg(errp, QERR_BUS_NO_HOTPLUG, bus->name);
             }
@@ -711,18 +685,24 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp)
      * set dev's parent and register its id.
      * If it fails it means the id is already taken.
      */
-    if (!qdev_set_id(dev, g_strdup(qemu_opts_id(opts)), errp)) {
+    id = g_strdup(qdict_get_try_str(opts, "id"));
+    if (!qdev_set_id(dev, id, errp)) {
         goto err_del_dev;
     }
 
     /* set properties */
-    if (qemu_opt_foreach(opts, set_property, dev, errp)) {
+    dev->opts = qdict_clone_shallow(opts);
+    qdict_del(dev->opts, "driver");
+    qdict_del(dev->opts, "bus");
+    qdict_del(dev->opts, "id");
+
+    object_set_properties_from_keyval(&dev->parent_obj, dev->opts, from_json,
+                                      errp);
+    if (*errp) {
         goto err_del_dev;
     }
 
-    dev->opts = opts;
     if (!qdev_realize(DEVICE(dev), bus, errp)) {
-        dev->opts = NULL;
         goto err_del_dev;
     }
     return dev;
@@ -735,6 +715,19 @@ err_del_dev:
     return NULL;
 }
 
+/* Takes ownership of @opts on success */
+DeviceState *qdev_device_add(QemuOpts *opts, Error **errp)
+{
+    QDict *qdict = qemu_opts_to_qdict(opts, NULL);
+    DeviceState *ret;
+
+    ret = qdev_device_add_from_qdict(qdict, false, errp);
+    if (ret) {
+        qemu_opts_del(opts);
+    }
+    qobject_unref(qdict);
+    return ret;
+}
 
 #define qdev_printf(fmt, ...) monitor_printf(mon, "%*s" fmt, indent, "", ## __VA_ARGS__)
 static void qbus_print(Monitor *mon, BusState *bus, int indent);