new file mode 100644
@@ -0,0 +1,203 @@
+/*
+ * Copyright © 2020, 2021 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL-v2, version 2 or later.
+ *
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+
+#include "qemu/error-report.h"
+#include "qemu/notify.h"
+#include "qom/object_interfaces.h"
+#include "hw/qdev-core.h"
+#include "io/channel.h"
+#include "hw/qdev-core.h"
+#include "hw/remote/machine.h"
+#include "io/channel-util.h"
+#include "qapi/error.h"
+#include "sysemu/sysemu.h"
+#include "hw/pci/pci.h"
+#include "qemu/sockets.h"
+#include "monitor/monitor.h"
+
+#define TYPE_REMOTE_OBJECT "x-remote-object"
+OBJECT_DECLARE_TYPE(RemoteObject, RemoteObjectClass, REMOTE_OBJECT)
+
+struct RemoteObjectClass {
+ ObjectClass parent_class;
+
+ unsigned int nr_devs;
+ unsigned int max_devs;
+};
+
+struct RemoteObject {
+ /* private */
+ Object parent;
+
+ Notifier machine_done;
+
+ int32_t fd;
+ char *devid;
+
+ QIOChannel *ioc;
+
+ DeviceState *dev;
+ DeviceListener listener;
+};
+
+static void remote_object_set_fd(Object *obj, const char *str, Error **errp)
+{
+ RemoteObject *o = REMOTE_OBJECT(obj);
+ int fd = -1;
+
+ fd = monitor_fd_param(monitor_cur(), str, errp);
+ if (fd == -1) {
+ error_prepend(errp, "Could not parse remote object fd %s:", str);
+ return;
+ }
+
+ if (!fd_is_socket(fd)) {
+ error_setg(errp, "File descriptor '%s' is not a socket", str);
+ close(fd);
+ return;
+ }
+
+ o->fd = fd;
+}
+
+static void remote_object_set_devid(Object *obj, const char *str, Error **errp)
+{
+ RemoteObject *o = REMOTE_OBJECT(obj);
+
+ g_free(o->devid);
+
+ o->devid = g_strdup(str);
+}
+
+static void remote_object_unrealize_listener(DeviceListener *listener,
+ DeviceState *dev)
+{
+ RemoteObject *o = container_of(listener, RemoteObject, listener);
+
+ if (o->dev == dev) {
+ object_unref(OBJECT(o));
+ }
+}
+
+static void remote_object_machine_done(Notifier *notifier, void *data)
+{
+ RemoteObject *o = container_of(notifier, RemoteObject, machine_done);
+ DeviceState *dev = NULL;
+ QIOChannel *ioc = NULL;
+ Coroutine *co = NULL;
+ RemoteCommDev *comdev = NULL;
+ Error *err = NULL;
+
+ dev = qdev_find_recursive(sysbus_get_default(), o->devid);
+ if (!dev || !object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
+ error_report("%s is not a PCI device", o->devid);
+ return;
+ }
+
+ ioc = qio_channel_new_fd(o->fd, &err);
+ if (!ioc) {
+ error_report_err(err);
+ return;
+ }
+ qio_channel_set_blocking(ioc, false, NULL);
+
+ o->dev = dev;
+
+ o->listener.unrealize = remote_object_unrealize_listener;
+ device_listener_register(&o->listener);
+
+ /* co-routine should free this. */
+ comdev = g_new0(RemoteCommDev, 1);
+ *comdev = (RemoteCommDev) {
+ .ioc = ioc,
+ .dev = PCI_DEVICE(dev),
+ };
+
+ co = qemu_coroutine_create(mpqemu_remote_msg_loop_co, comdev);
+ qemu_coroutine_enter(co);
+}
+
+static void remote_object_init(Object *obj)
+{
+ RemoteObjectClass *k = REMOTE_OBJECT_GET_CLASS(obj);
+ RemoteObject *o = REMOTE_OBJECT(obj);
+
+ if (k->nr_devs >= k->max_devs) {
+ error_report("Reached maximum number of devices: %u", k->max_devs);
+ return;
+ }
+
+ o->ioc = NULL;
+ o->fd = -1;
+ o->devid = NULL;
+
+ k->nr_devs++;
+
+ o->machine_done.notify = remote_object_machine_done;
+ qemu_add_machine_init_done_notifier(&o->machine_done);
+}
+
+static void remote_object_finalize(Object *obj)
+{
+ RemoteObjectClass *k = REMOTE_OBJECT_GET_CLASS(obj);
+ RemoteObject *o = REMOTE_OBJECT(obj);
+
+ device_listener_unregister(&o->listener);
+
+ if (o->ioc) {
+ qio_channel_shutdown(o->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
+ qio_channel_close(o->ioc, NULL);
+ }
+
+ object_unref(OBJECT(o->ioc));
+
+ k->nr_devs--;
+ g_free(o->devid);
+}
+
+static void remote_object_class_init(ObjectClass *klass, void *data)
+{
+ RemoteObjectClass *k = REMOTE_OBJECT_CLASS(klass);
+
+ /*
+ * Limit number of supported devices to 1. This is done to avoid devices
+ * from one VM accessing the RAM of another VM. This is done until we
+ * start using separate address spaces for individual devices.
+ */
+ k->max_devs = 1;
+ k->nr_devs = 0;
+
+ object_class_property_add_str(klass, "fd", NULL, remote_object_set_fd);
+ object_class_property_add_str(klass, "devid", NULL,
+ remote_object_set_devid);
+}
+
+static const TypeInfo remote_object_info = {
+ .name = TYPE_REMOTE_OBJECT,
+ .parent = TYPE_OBJECT,
+ .instance_size = sizeof(RemoteObject),
+ .instance_init = remote_object_init,
+ .instance_finalize = remote_object_finalize,
+ .class_size = sizeof(RemoteObjectClass),
+ .class_init = remote_object_class_init,
+ .interfaces = (InterfaceInfo[]) {
+ { TYPE_USER_CREATABLE },
+ { }
+ }
+};
+
+static void register_types(void)
+{
+ type_register_static(&remote_object_info);
+}
+
+type_init(register_types);
@@ -3187,6 +3187,7 @@ F: include/hw/remote/machine.h
F: hw/remote/mpqemu-link.c
F: include/hw/remote/mpqemu-link.h
F: hw/remote/message.c
+F: hw/remote/remote-obj.c
Build and test automation
-------------------------
@@ -3,5 +3,6 @@ remote_ss = ss.source_set()
remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('machine.c'))
remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('mpqemu-link.c'))
remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('message.c'))
+remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('remote-obj.c'))
softmmu_ss.add_all(when: 'CONFIG_MULTIPROCESS', if_true: remote_ss)