Re: [Qemu-devel] [PATCH v3 6/6] Add dbus-vmstate object

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Marc-André Lureau (marcandre.lureau@redhat.com) wrote:
> When instanciated, this object will connect to the given D-Bus
> bus. During migration, it will take the data from org.qemu.VMState1
> instances.
> 
> See documentation for further details.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

I could do with this being in smaller chunks; it's a bit of a big
uncommented patch.

Dave

> ---
>  MAINTAINERS                   |   6 +
>  backends/Makefile.objs        |   4 +
>  backends/dbus-vmstate.c       | 530 ++++++++++++++++++++++++++++++++++
>  configure                     |   7 +
>  docs/interop/dbus-vmstate.rst |  68 +++++
>  docs/interop/index.rst        |   1 +
>  tests/Makefile.include        |  19 +-
>  tests/dbus-vmstate-daemon.sh  |  95 ++++++
>  tests/dbus-vmstate-test.c     | 386 +++++++++++++++++++++++++
>  tests/dbus-vmstate1.xml       |  12 +
>  10 files changed, 1127 insertions(+), 1 deletion(-)
>  create mode 100644 backends/dbus-vmstate.c
>  create mode 100644 docs/interop/dbus-vmstate.rst
>  create mode 100755 tests/dbus-vmstate-daemon.sh
>  create mode 100644 tests/dbus-vmstate-test.c
>  create mode 100644 tests/dbus-vmstate1.xml
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 50eaf005f4..f641870c40 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2153,6 +2153,12 @@ F: tests/migration-test.c
>  F: docs/devel/migration.rst
>  F: qapi/migration.json
>  
> +DBus VMState
> +M: Marc-André Lureau <marcandre.lureau@redhat.com>
> +S: Maintained
> +F: backends/dbus-vmstate.c
> +F: tests/dbus-vmstate*
> +
>  Seccomp
>  M: Eduardo Otubo <otubo@redhat.com>
>  S: Supported
> diff --git a/backends/Makefile.objs b/backends/Makefile.objs
> index f0691116e8..28a847cd57 100644
> --- a/backends/Makefile.objs
> +++ b/backends/Makefile.objs
> @@ -17,3 +17,7 @@ endif
>  common-obj-$(call land,$(CONFIG_VHOST_USER),$(CONFIG_VIRTIO)) += vhost-user.o
>  
>  common-obj-$(CONFIG_LINUX) += hostmem-memfd.o
> +
> +common-obj-$(CONFIG_GIO) += dbus-vmstate.o
> +dbus-vmstate.o-cflags = $(GIO_CFLAGS)
> +dbus-vmstate.o-libs = $(GIO_LIBS)
> diff --git a/backends/dbus-vmstate.c b/backends/dbus-vmstate.c
> new file mode 100644
> index 0000000000..559f5430c5
> --- /dev/null
> +++ b/backends/dbus-vmstate.c
> @@ -0,0 +1,530 @@
> +/*
> + * QEMU dbus-vmstate
> + *
> + * Copyright (C) 2019 Red Hat Inc
> + *
> + * Authors:
> + *  Marc-André Lureau <marcandre.lureau@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qemu/units.h"
> +#include "qemu/error-report.h"
> +#include "qapi/error.h"
> +#include "qom/object_interfaces.h"
> +#include "qapi/qmp/qerror.h"
> +#include "migration/vmstate.h"
> +#include <gio/gio.h>
> +
> +typedef struct DBusVMState DBusVMState;
> +typedef struct DBusVMStateClass DBusVMStateClass;
> +
> +#define TYPE_DBUS_VMSTATE "dbus-vmstate"
> +#define DBUS_VMSTATE(obj)                                \
> +    OBJECT_CHECK(DBusVMState, (obj), TYPE_DBUS_VMSTATE)
> +#define DBUS_VMSTATE_GET_CLASS(obj)                              \
> +    OBJECT_GET_CLASS(DBusVMStateClass, (obj), TYPE_DBUS_VMSTATE)
> +#define DBUS_VMSTATE_CLASS(klass)                                    \
> +    OBJECT_CLASS_CHECK(DBusVMStateClass, (klass), TYPE_DBUS_VMSTATE)
> +
> +struct DBusVMStateClass {
> +    ObjectClass parent_class;
> +};
> +
> +struct DBusVMState {
> +    Object parent;
> +
> +    GDBusConnection *bus;
> +    char *dbus_addr;
> +    char *id_list;
> +
> +    uint32_t data_size;
> +    uint8_t *data;
> +};
> +
> +static const GDBusPropertyInfo vmstate_property_info[] = {
> +    { -1, (char *) "Id", (char *) "s",
> +      G_DBUS_PROPERTY_INFO_FLAGS_READABLE, NULL },
> +};
> +
> +static const GDBusPropertyInfo * const vmstate_property_info_pointers[] = {
> +    &vmstate_property_info[0],
> +    NULL
> +};
> +
> +static const GDBusInterfaceInfo vmstate1_interface_info = {
> +    -1,
> +    (char *) "org.qemu.VMState1",
> +    (GDBusMethodInfo **) NULL,
> +    (GDBusSignalInfo **) NULL,
> +    (GDBusPropertyInfo **) &vmstate_property_info_pointers,
> +    NULL,
> +};
> +
> +#define DBUS_VMSTATE_SIZE_LIMIT (1 * MiB)
> +
> +static char **
> +dbus_get_vmstate1_names(DBusVMState *self, GError **err)
> +{
> +    g_autoptr(GDBusProxy) proxy = NULL;
> +    g_autoptr(GVariant) result = NULL;
> +    g_autoptr(GVariant) child = NULL;
> +
> +    proxy = g_dbus_proxy_new_sync(self->bus, G_DBUS_PROXY_FLAGS_NONE, NULL,
> +                                  "org.freedesktop.DBus",
> +                                  "/org/freedesktop/DBus",
> +                                  "org.freedesktop.DBus",
> +                                  NULL, err);
> +    if (!proxy) {
> +        return NULL;
> +    }
> +
> +    result = g_dbus_proxy_call_sync(proxy, "ListQueuedOwners",
> +                                    g_variant_new("(s)", "org.qemu.VMState1"),
> +                                    G_DBUS_CALL_FLAGS_NO_AUTO_START,
> +                                    -1, NULL, err);
> +    if (!result) {
> +        return NULL;
> +    }
> +
> +    child = g_variant_get_child_value(result, 0);
> +    return g_variant_dup_strv(child, NULL);
> +}
> +
> +static GHashTable *
> +get_id_list_set(DBusVMState *self)
> +{
> +    g_auto(GStrv) ids = NULL;
> +    g_autoptr(GHashTable) set = NULL;
> +    int i;
> +
> +    if (!self->id_list) {
> +        return NULL;
> +    }
> +
> +    ids = g_strsplit(self->id_list, ",", -1);
> +    set = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, NULL);
> +    for (i = 0; ids[i]; i++) {
> +        g_hash_table_add(set, ids[i]);
> +        ids[i] = NULL;
> +    }
> +
> +    return g_steal_pointer(&set);
> +}
> +
> +static GHashTable *
> +dbus_get_proxies(DBusVMState *self, GError **err)
> +{
> +    g_autoptr(GError) local_err = NULL;
> +    g_autoptr(GHashTable) proxies = NULL;
> +    g_autoptr(GHashTable) ids = NULL;
> +    g_auto(GStrv) names = NULL;
> +    size_t i;
> +
> +    ids = get_id_list_set(self);
> +    proxies = g_hash_table_new_full(g_str_hash, g_str_equal,
> +                                    g_free, g_object_unref);
> +
> +    names = dbus_get_vmstate1_names(self, &local_err);
> +    if (!names) {
> +        if (g_error_matches(local_err,
> +                            G_DBUS_ERROR, G_DBUS_ERROR_NAME_HAS_NO_OWNER)) {
> +            return proxies;
> +        }
> +        g_propagate_error(err, local_err);
> +        return NULL;
> +    }
> +
> +    for (i = 0; names[i]; i++) {
> +        g_autoptr(GDBusProxy) proxy = NULL;
> +        g_autoptr(GVariant) result = NULL;
> +        g_autofree char *id = NULL;
> +        size_t size;
> +
> +        proxy = g_dbus_proxy_new_sync(self->bus, G_DBUS_PROXY_FLAGS_NONE,
> +                    (GDBusInterfaceInfo *) &vmstate1_interface_info,
> +                    names[i],
> +                    "/org/qemu/VMState1",
> +                    "org.qemu.VMState1",
> +                    NULL, err);
> +        if (!proxy) {
> +            return NULL;
> +        }
> +
> +        result = g_dbus_proxy_get_cached_property(proxy, "Id");
> +        if (!result) {
> +            g_set_error_literal(err, G_IO_ERROR, G_IO_ERROR_FAILED,
> +                                "VMState Id property is missing.");
> +            return NULL;
> +        }
> +
> +        id = g_variant_dup_string(result, &size);
> +        if (ids && !g_hash_table_remove(ids, id)) {
> +            g_clear_pointer(&id, g_free);
> +            g_clear_object(&proxy);
> +            continue;
> +        }
> +        if (size == 0 || size >= 256) {
> +            g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
> +                        "VMState Id '%s' is invalid.", id);
> +            return NULL;
> +        }
> +
> +        if (!g_hash_table_insert(proxies, id, proxy)) {
> +            g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
> +                        "Duplicated VMState Id '%s'", id);
> +            return NULL;
> +        }
> +        id = NULL;
> +        proxy = NULL;
> +
> +        g_clear_pointer(&result, g_variant_unref);
> +    }
> +
> +    if (ids) {
> +        g_autofree char **left = NULL;
> +
> +        left = (char **)g_hash_table_get_keys_as_array(ids, NULL);
> +        if (*left) {
> +            g_autofree char *leftids = g_strjoinv(",", left);
> +            g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
> +                        "Required VMState Id are missing: %s", leftids);
> +            return NULL;
> +        }
> +    }
> +
> +    return g_steal_pointer(&proxies);
> +}
> +
> +static int
> +dbus_load_state_proxy(GDBusProxy *proxy, const uint8_t *data, size_t size)
> +{
> +    g_autoptr(GError) err = NULL;
> +    g_autoptr(GVariant) result = NULL;
> +    g_autoptr(GVariant) value = NULL;
> +
> +    value = g_variant_new_fixed_array(G_VARIANT_TYPE_BYTE,
> +                                      data, size, sizeof(char));
> +    result = g_dbus_proxy_call_sync(proxy, "Load",
> +                                    g_variant_new("(@ay)",
> +                                                  g_steal_pointer(&value)),
> +                                    G_DBUS_CALL_FLAGS_NO_AUTO_START,
> +                                    -1, NULL, &err);
> +    if (!result) {
> +        error_report("Failed to Load: %s", err->message);
> +        return -1;
> +    }
> +
> +    return 0;
> +}
> +
> +static int dbus_vmstate_post_load(void *opaque, int version_id)
> +{
> +    DBusVMState *self = DBUS_VMSTATE(opaque);
> +    g_autoptr(GInputStream) m = NULL;
> +    g_autoptr(GDataInputStream) s = NULL;
> +    g_autoptr(GError) err = NULL;
> +    g_autoptr(GHashTable) proxies = NULL;
> +    uint32_t nelem;
> +
> +    proxies = dbus_get_proxies(self, &err);
> +    if (!proxies) {
> +        error_report("Failed to get proxies: %s", err->message);
> +        return -1;
> +    }
> +
> +    m = g_memory_input_stream_new_from_data(self->data, self->data_size, NULL);
> +    s = g_data_input_stream_new(m);
> +    g_data_input_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
> +
> +    nelem = g_data_input_stream_read_uint32(s, NULL, &err);
> +    if (err) {
> +        goto error;
> +    }
> +
> +    while (nelem > 0) {
> +        GDBusProxy *proxy = NULL;
> +        uint32_t len;
> +        gsize bytes_read, avail;
> +        char id[256];
> +
> +        len = g_data_input_stream_read_uint32(s, NULL, &err);
> +        if (err) {
> +            goto error;
> +        }
> +        if (len >= 256) {
> +            error_report("Invalid DBus vmstate proxy name %u", len);
> +            return -1;
> +        }
> +        if (!g_input_stream_read_all(G_INPUT_STREAM(s), id, len,
> +                                     &bytes_read, NULL, &err)) {
> +            goto error;
> +        }
> +        g_return_val_if_fail(bytes_read == len, -1);
> +        id[len] = 0;
> +
> +        proxy = g_hash_table_lookup(proxies, id);
> +        if (!proxy) {
> +            error_report("Failed to find proxy Id '%s'", id);
> +            return -1;
> +        }
> +
> +        len = g_data_input_stream_read_uint32(s, NULL, &err);
> +        avail = g_buffered_input_stream_get_available(
> +            G_BUFFERED_INPUT_STREAM(s));
> +
> +        if (len > DBUS_VMSTATE_SIZE_LIMIT || len > avail) {
> +            error_report("Invalid vmstate size: %u", len);
> +            return -1;
> +        }
> +
> +        if (dbus_load_state_proxy(proxy,
> +                g_buffered_input_stream_peek_buffer(G_BUFFERED_INPUT_STREAM(s),
> +                                                    NULL),
> +                len) < 0) {
> +            error_report("Failed to restore Id '%s'", id);
> +            return -1;
> +        }
> +
> +        if (!g_seekable_seek(G_SEEKABLE(s), len, G_SEEK_CUR, NULL, &err)) {
> +            goto error;
> +        }
> +
> +        nelem -= 1;
> +    }
> +
> +    return 0;
> +
> +error:
> +    error_report("Failed to read from stream: %s", err->message);
> +    return -1;
> +}
> +
> +static void
> +dbus_save_state_proxy(gpointer key,
> +                      gpointer value,
> +                      gpointer user_data)
> +{
> +    GDataOutputStream *s = user_data;
> +    const char *id = key;
> +    GDBusProxy *proxy = value;
> +    g_autoptr(GVariant) result = NULL;
> +    g_autoptr(GVariant) child = NULL;
> +    g_autoptr(GError) err = NULL;
> +    const uint8_t *data;
> +    gsize size;
> +
> +    result = g_dbus_proxy_call_sync(proxy, "Save",
> +                                    NULL, G_DBUS_CALL_FLAGS_NO_AUTO_START,
> +                                    -1, NULL, &err);
> +    if (!result) {
> +        error_report("Failed to Save: %s", err->message);
> +        return;
> +    }
> +
> +    child = g_variant_get_child_value(result, 0);
> +    data = g_variant_get_fixed_array(child, &size, sizeof(char));
> +    if (!data) {
> +        error_report("Failed to Save: not a byte array");
> +        return;
> +    }
> +    if (size > DBUS_VMSTATE_SIZE_LIMIT) {
> +        error_report("Too large vmstate data to save: %lu", size);
> +        return;
> +    }
> +
> +    if (!g_data_output_stream_put_uint32(s, strlen(id), NULL, &err) ||
> +        !g_data_output_stream_put_string(s, id, NULL, &err) ||
> +        !g_data_output_stream_put_uint32(s, size, NULL, &err) ||
> +        !g_output_stream_write_all(G_OUTPUT_STREAM(s),
> +                                   data, size, NULL, NULL, &err)) {
> +        error_report("Failed to write to stream: %s", err->message);
> +    }
> +}
> +
> +static int dbus_vmstate_pre_save(void *opaque)
> +{
> +    DBusVMState *self = DBUS_VMSTATE(opaque);
> +    g_autoptr(GOutputStream) m = NULL;
> +    g_autoptr(GDataOutputStream) s = NULL;
> +    g_autoptr(GHashTable) proxies = NULL;
> +    g_autoptr(GError) err = NULL;
> +
> +    proxies = dbus_get_proxies(self, &err);
> +    if (!proxies) {
> +        error_report("Failed to get proxies: %s", err->message);
> +        return -1;
> +    }
> +
> +    m = g_memory_output_stream_new_resizable();
> +    s = g_data_output_stream_new(m);
> +    g_data_output_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
> +
> +    if (!g_data_output_stream_put_uint32(s, g_hash_table_size(proxies),
> +                                         NULL, &err)) {
> +        error_report("Failed to write to stream: %s", err->message);
> +        return -1;
> +    }
> +
> +    g_hash_table_foreach(proxies, dbus_save_state_proxy, s);
> +
> +    if (g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m))
> +        > UINT32_MAX) {
> +        error_report("DBus vmstate buffer is too large");
> +        return -1;
> +    }
> +
> +    if (!g_output_stream_close(G_OUTPUT_STREAM(m), NULL, &err)) {
> +        error_report("Failed to close stream: %s", err->message);
> +        return -1;
> +    }
> +
> +    g_free(self->data);
> +    self->data_size =
> +        g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m));
> +    self->data =
> +        g_memory_output_stream_steal_data(G_MEMORY_OUTPUT_STREAM(m));
> +
> +    return 0;
> +}
> +
> +static const VMStateDescription dbus_vmstate = {
> +    .name = TYPE_DBUS_VMSTATE,
> +    .version_id = 0,
> +    .pre_save = dbus_vmstate_pre_save,
> +    .post_load = dbus_vmstate_post_load,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_UINT32(data_size, DBusVMState),
> +        VMSTATE_VBUFFER_ALLOC_UINT32(data, DBusVMState, 0, 0, data_size),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +static void
> +dbus_vmstate_complete(UserCreatable *uc, Error **errp)
> +{
> +    DBusVMState *self = DBUS_VMSTATE(uc);
> +    GError *err = NULL;
> +    GDBusConnection *bus;
> +
> +    if (!object_resolve_path_type("", TYPE_DBUS_VMSTATE, NULL)) {
> +        error_setg(errp, "There is already an instance of %s",
> +                   TYPE_DBUS_VMSTATE);
> +        return;
> +    }
> +
> +    if (!self->dbus_addr) {
> +        error_setg(errp, QERR_MISSING_PARAMETER, "addr");
> +        return;
> +    }
> +
> +    bus = g_dbus_connection_new_for_address_sync(self->dbus_addr,
> +             G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT |
> +             G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION,
> +             NULL, NULL, &err);
> +    if (err) {
> +        error_setg(errp, "failed to connect to DBus: '%s'", err->message);
> +        g_clear_error(&err);
> +    }
> +
> +    self->bus = bus;
> +
> +    if (vmstate_register(VMSTATE_IF(self), -1, &dbus_vmstate, self) < 0) {
> +        error_setg(errp, "Failed to register vmstate");
> +    }
> +}
> +
> +static void
> +dbus_vmstate_finalize(Object *o)
> +{
> +    DBusVMState *self = DBUS_VMSTATE(o);
> +
> +    vmstate_unregister(VMSTATE_IF(self), &dbus_vmstate, self);
> +
> +    g_clear_object(&self->bus);
> +    g_free(self->dbus_addr);
> +    g_free(self->id_list);
> +    g_free(self->data);
> +}
> +
> +static char *
> +get_dbus_addr(Object *o, Error **errp)
> +{
> +    DBusVMState *self = DBUS_VMSTATE(o);
> +
> +    return g_strdup(self->dbus_addr);
> +}
> +
> +static void
> +set_dbus_addr(Object *o, const char *str, Error **errp)
> +{
> +    DBusVMState *self = DBUS_VMSTATE(o);
> +
> +    g_free(self->dbus_addr);
> +    self->dbus_addr = g_strdup(str);
> +}
> +
> +static char *
> +get_id_list(Object *o, Error **errp)
> +{
> +    DBusVMState *self = DBUS_VMSTATE(o);
> +
> +    return g_strdup(self->id_list);
> +}
> +
> +static void
> +set_id_list(Object *o, const char *str, Error **errp)
> +{
> +    DBusVMState *self = DBUS_VMSTATE(o);
> +
> +    g_free(self->id_list);
> +    self->id_list = g_strdup(str);
> +}
> +
> +static char *
> +dbus_vmstate_get_id(VMStateIf *vmif)
> +{
> +    return g_strdup(TYPE_DBUS_VMSTATE);
> +}
> +
> +static void
> +dbus_vmstate_class_init(ObjectClass *oc, void *data)
> +{
> +    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
> +    VMStateIfClass *vc = VMSTATE_IF_CLASS(oc);
> +
> +    ucc->complete = dbus_vmstate_complete;
> +    vc->get_id = dbus_vmstate_get_id;
> +
> +    object_class_property_add_str(oc, "addr",
> +                                  get_dbus_addr, set_dbus_addr,
> +                                  &error_abort);
> +    object_class_property_add_str(oc, "id-list",
> +                                  get_id_list, set_id_list,
> +                                  &error_abort);
> +}
> +
> +static const TypeInfo dbus_vmstate_info = {
> +    .name = TYPE_DBUS_VMSTATE,
> +    .parent = TYPE_OBJECT,
> +    .instance_size = sizeof(DBusVMState),
> +    .instance_finalize = dbus_vmstate_finalize,
> +    .class_size = sizeof(DBusVMStateClass),
> +    .class_init = dbus_vmstate_class_init,
> +    .interfaces = (InterfaceInfo[]) {
> +        { TYPE_USER_CREATABLE },
> +        { TYPE_VMSTATE_IF },
> +        { }
> +    }
> +};
> +
> +static void
> +register_types(void)
> +{
> +    type_register_static(&dbus_vmstate_info);
> +}
> +
> +type_init(register_types);
> diff --git a/configure b/configure
> index 95134c0180..0a6eb2ebcd 100755
> --- a/configure
> +++ b/configure
> @@ -3665,10 +3665,16 @@ if $pkg_config --atleast-version=$glib_req_ver gio-2.0; then
>      gio=yes
>      gio_cflags=$($pkg_config --cflags gio-2.0)
>      gio_libs=$($pkg_config --libs gio-2.0)
> +    gdbus_codegen=$($pkg_config --variable=gdbus_codegen gio-2.0)
>  else
>      gio=no
>  fi
>  
> +if $pkg_config --atleast-version=$glib_req_ver gio-unix-2.0; then
> +    gio_cflags="$gio_cflags $($pkg_config --cflags gio-unix-2.0)"
> +    gio_libs="$gio_libs $($pkg_config --libs gio-unix-2.0)"
> +fi
> +
>  # Sanity check that the current size_t matches the
>  # size that glib thinks it should be. This catches
>  # problems on multi-arch where people try to build
> @@ -6831,6 +6837,7 @@ if test "$gio" = "yes" ; then
>      echo "CONFIG_GIO=y" >> $config_host_mak
>      echo "GIO_CFLAGS=$gio_cflags" >> $config_host_mak
>      echo "GIO_LIBS=$gio_libs" >> $config_host_mak
> +    echo "GDBUS_CODEGEN=$gdbus_codegen" >> $config_host_mak
>  fi
>  echo "CONFIG_TLS_PRIORITY=\"$tls_priority\"" >> $config_host_mak
>  if test "$gnutls" = "yes" ; then
> diff --git a/docs/interop/dbus-vmstate.rst b/docs/interop/dbus-vmstate.rst
> new file mode 100644
> index 0000000000..78070be1bd
> --- /dev/null
> +++ b/docs/interop/dbus-vmstate.rst
> @@ -0,0 +1,68 @@
> +=============
> +D-Bus VMState
> +=============
> +
> +Introduction
> +============
> +
> +The QEMU dbus-vmstate object aim is to migrate helpers data running on
> +a QEMU D-Bus bus. (refer to the :doc:`dbus` document for
> +recommendation on D-Bus usage)
> +
> +Upon migration, QEMU will go through the queue of
> +``org.qemu.VMState1`` D-Bus name owners and query their ``Id``. It
> +must be unique among the helpers.
> +
> +It will then save arbitrary data of each Id to be transferred in the
> +migration stream and restored/loaded at the corresponding destination
> +helper.
> +
> +The data amount to be transferred is limited to 1Mb. The state must be
> +saved quickly (a few seconds maximum). (D-Bus imposes a time limit on
> +reply anyway, and migration would fail if data isn't given quickly
> +enough)
> +
> +dbus-vmstate object can be configured with the expected list of
> +helpers by setting its ``id-list`` property, with a coma-separated
> +``Id`` list.
> +
> +Interface
> +=========
> +
> +On object path ``/org/qemu/VMState1``, the following
> +``org.qemu.VMState1`` interface should be implemented:
> +
> +.. code:: xml
> +
> +  <interface name="org.qemu.VMState1">
> +    <property name="Id" type="s" access="read"/>
> +    <method name="Load">
> +      <arg type="ay" name="data" direction="in"/>
> +    </method>
> +    <method name="Save">
> +      <arg type="ay" name="data" direction="out"/>
> +    </method>
> +  </interface>
> +
> +"Id" property
> +-------------
> +
> +A string that identifies the helper uniquely.
> +
> +Load(in u8[] bytes) method
> +--------------------------
> +
> +The method called on destination with the state to restore.
> +
> +The helper may be initially started in a waiting state (with
> +an --incoming argument for example), and it may resume on success.
> +
> +An error may be returned to the caller.
> +
> +Save(out u8[] bytes) method
> +---------------------------
> +
> +The method called on the source to get the current state to be
> +migrated. The helper should continue to run normally.
> +
> +An error may be returned to the caller.
> diff --git a/docs/interop/index.rst b/docs/interop/index.rst
> index fa4478ce2e..75832f44ac 100644
> --- a/docs/interop/index.rst
> +++ b/docs/interop/index.rst
> @@ -14,6 +14,7 @@ Contents:
>  
>     bitmaps
>     dbus
> +   dbus-vmstate
>     live-block-operations
>     pr-helper
>     vhost-user
> diff --git a/tests/Makefile.include b/tests/Makefile.include
> index d4502a30eb..eb40e8a5e7 100644
> --- a/tests/Makefile.include
> +++ b/tests/Makefile.include
> @@ -158,7 +158,9 @@ check-qtest-pci-$(CONFIG_RTL8139_PCI) += tests/rtl8139-test$(EXESUF)
>  check-qtest-pci-$(CONFIG_VGA) += tests/display-vga-test$(EXESUF)
>  check-qtest-pci-$(CONFIG_HDA) += tests/intel-hda-test$(EXESUF)
>  check-qtest-pci-$(CONFIG_IVSHMEM_DEVICE) += tests/ivshmem-test$(EXESUF)
> -
> +ifneq ($(GDBUS_CODEGEN),)
> +check-qtest-pci-$(CONFIG_GIO) += tests/dbus-vmstate-test$(EXESUF)
> +endif
>  check-qtest-i386-$(CONFIG_ISA_TESTDEV) = tests/endianness-test$(EXESUF)
>  check-qtest-i386-y += tests/fdc-test$(EXESUF)
>  check-qtest-i386-y += tests/ide-test$(EXESUF)
> @@ -620,6 +622,19 @@ tests/qapi-schema/doc-good.test.texi: $(SRC_PATH)/tests/qapi-schema/doc-good.jso
>  	@mv tests/qapi-schema/doc-good-qapi-doc.texi $@
>  	@rm -f tests/qapi-schema/doc-good-qapi-*.[ch] tests/qapi-schema/doc-good-qmp-*.[ch]
>  
> +tests/dbus-vmstate1.h tests/dbus-vmstate1.c: tests/dbus-vmstate1-gen-timestamp ;
> +tests/dbus-vmstate1-gen-timestamp: $(SRC_PATH)/tests/dbus-vmstate1.xml
> +	$(call quiet-command,$(GDBUS_CODEGEN) $< \
> +		--interface-prefix org.qemu --generate-c-code tests/dbus-vmstate1, \
> +		"GEN","$(@:%-timestamp=%)")
> +	@>$@
> +
> +tests/dbus-vmstate-test.o-cflags := -DSRCDIR="$(SRC_PATH)"
> +tests/dbus-vmstate1.o-cflags := $(GIO_CFLAGS)
> +tests/dbus-vmstate1.o-libs := $(GIO_LIBS)
> +
> +tests/dbus-vmstate-test.o: tests/dbus-vmstate1.h
> +
>  tests/test-string-output-visitor$(EXESUF): tests/test-string-output-visitor.o $(test-qapi-obj-y)
>  tests/test-string-input-visitor$(EXESUF): tests/test-string-input-visitor.o $(test-qapi-obj-y)
>  tests/test-qmp-event$(EXESUF): tests/test-qmp-event.o $(test-qapi-obj-y) tests/test-qapi-events.o
> @@ -822,6 +837,7 @@ tests/test-filter-mirror$(EXESUF): tests/test-filter-mirror.o $(qtest-obj-y)
>  tests/test-filter-redirector$(EXESUF): tests/test-filter-redirector.o $(qtest-obj-y)
>  tests/test-x86-cpuid-compat$(EXESUF): tests/test-x86-cpuid-compat.o $(qtest-obj-y)
>  tests/ivshmem-test$(EXESUF): tests/ivshmem-test.o contrib/ivshmem-server/ivshmem-server.o $(libqos-pc-obj-y) $(libqos-spapr-obj-y)
> +tests/dbus-vmstate-test$(EXESUF): tests/dbus-vmstate-test.o tests/dbus-vmstate1.o $(libqos-pc-obj-y) $(libqos-spapr-obj-y)
>  tests/vhost-user-bridge$(EXESUF): tests/vhost-user-bridge.o $(test-util-obj-y) libvhost-user.a
>  tests/test-uuid$(EXESUF): tests/test-uuid.o $(test-util-obj-y)
>  tests/test-arm-mptimer$(EXESUF): tests/test-arm-mptimer.o
> @@ -1176,6 +1192,7 @@ check-clean:
>  	rm -rf $(check-unit-y) tests/*.o $(QEMU_IOTESTS_HELPERS-y)
>  	rm -rf $(sort $(foreach target,$(SYSEMU_TARGET_LIST), $(check-qtest-$(target)-y)) $(check-qtest-generic-y))
>  	rm -f tests/test-qapi-gen-timestamp
> +	rm -f tests/dbus-vmstate1-gen-timestamp
>  	rm -rf $(TESTS_VENV_DIR) $(TESTS_RESULTS_DIR)
>  
>  clean: check-clean
> diff --git a/tests/dbus-vmstate-daemon.sh b/tests/dbus-vmstate-daemon.sh
> new file mode 100755
> index 0000000000..c4394ac918
> --- /dev/null
> +++ b/tests/dbus-vmstate-daemon.sh
> @@ -0,0 +1,95 @@
> +#!/bin/sh
> +
> +# dbus-daemon wrapper script for dbus-vmstate testing
> +#
> +# This script allows to tweak the dbus-daemon policy during the test
> +# to test different configurations.
> +#
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 2 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program; if not, see <http://www.gnu.org/licenses/>.
> +#
> +# Copyright (C) 2019 Red Hat, Inc.
> +
> +write_config()
> +{
> +    CONF="$1"
> +    cat > "$CONF" <<EOF
> +<busconfig>
> +  <type>session</type>
> +  <listen>unix:tmpdir=/tmp</listen>
> +
> +  <policy context="default">
> +     <!-- Holes must be punched in service configuration files for
> +          name ownership and sending method calls -->
> +     <deny own="*"/>
> +     <deny send_type="method_call"/>
> +
> +     <!-- Signals and reply messages (method returns, errors) are allowed
> +          by default -->
> +     <allow send_type="signal"/>
> +     <allow send_requested_reply="true" send_type="method_return"/>
> +     <allow send_requested_reply="true" send_type="error"/>
> +
> +     <!-- All messages may be received by default -->
> +     <allow receive_type="method_call"/>
> +     <allow receive_type="method_return"/>
> +     <allow receive_type="error"/>
> +     <allow receive_type="signal"/>
> +
> +     <!-- Allow anyone to talk to the message bus -->
> +     <allow send_destination="org.freedesktop.DBus"
> +            send_interface="org.freedesktop.DBus" />
> +     <allow send_destination="org.freedesktop.DBus"
> +            send_interface="org.freedesktop.DBus.Introspectable"/>
> +     <allow send_destination="org.freedesktop.DBus"
> +            send_interface="org.freedesktop.DBus.Properties"/>
> +     <!-- But disallow some specific bus services -->
> +     <deny send_destination="org.freedesktop.DBus"
> +           send_interface="org.freedesktop.DBus"
> +           send_member="UpdateActivationEnvironment"/>
> +     <deny send_destination="org.freedesktop.DBus"
> +           send_interface="org.freedesktop.DBus.Debug.Stats"/>
> +     <deny send_destination="org.freedesktop.DBus"
> +           send_interface="org.freedesktop.systemd1.Activator"/>
> +
> +     <allow own="org.qemu.VMState1"/>
> +     <allow send_destination="org.qemu.VMState1"/>
> +     <allow receive_sender="org.qemu.VMState1"/>
> +
> +  </policy>
> +
> +  <include if_selinux_enabled="yes"
> +   selinux_root_relative="yes">contexts/dbus_contexts</include>
> +
> +</busconfig>
> +EOF
> +}
> +
> +ARGS=
> +for arg in "$@"
> +do
> +    case $arg in
> +        --config-file=*)
> +          CONF="${arg#*=}"
> +          write_config "$CONF"
> +          ARGS="$ARGS $1"
> +          shift
> +        ;;
> +        *)
> +          ARGS="$ARGS $1"
> +          shift
> +        ;;
> +    esac
> +done
> +
> +exec dbus-daemon $ARGS
> diff --git a/tests/dbus-vmstate-test.c b/tests/dbus-vmstate-test.c
> new file mode 100644
> index 0000000000..bcf2372e15
> --- /dev/null
> +++ b/tests/dbus-vmstate-test.c
> @@ -0,0 +1,386 @@
> +#include "qemu/osdep.h"
> +#include <glib/gstdio.h>
> +#include <gio/gio.h>
> +#include "libqtest.h"
> +#include "qemu-common.h"
> +#include "dbus-vmstate1.h"
> +
> +static char *workdir;
> +
> +typedef struct TestServerId {
> +    const char *name;
> +    const char *data;
> +    size_t size;
> +} TestServerId;
> +
> +static const TestServerId idA = {
> +    "idA", "I'am\0idA!", sizeof("I'am\0idA!")
> +};
> +
> +static const TestServerId idB = {
> +    "idB", "I'am\0idB!", sizeof("I'am\0idB!")
> +};
> +
> +typedef struct TestServer {
> +    const TestServerId *id;
> +    bool save_called;
> +    bool load_called;
> +} TestServer;
> +
> +typedef struct Test {
> +    const char *id_list;
> +    bool migrate_fail;
> +    bool without_dst_b;
> +    TestServer srcA;
> +    TestServer dstA;
> +    TestServer srcB;
> +    TestServer dstB;
> +    GMainLoop *loop;
> +    QTestState *src_qemu;
> +} Test;
> +
> +static gboolean
> +vmstate_load(VMState1 *object, GDBusMethodInvocation *invocation,
> +             const gchar *arg_data, gpointer user_data)
> +{
> +    TestServer *h = user_data;
> +    g_autoptr(GVariant) var = NULL;
> +    GVariant *args;
> +    const uint8_t *data;
> +    size_t size;
> +
> +    args = g_dbus_method_invocation_get_parameters(invocation);
> +    var = g_variant_get_child_value(args, 0);
> +    data = g_variant_get_fixed_array(var, &size, sizeof(char));
> +    g_assert_cmpuint(size, ==, h->id->size);
> +    g_assert(!memcmp(data, h->id->data, h->id->size));
> +    h->load_called = true;
> +
> +    g_dbus_method_invocation_return_value(invocation, g_variant_new("()"));
> +    return TRUE;
> +}
> +
> +static gboolean
> +vmstate_save(VMState1 *object, GDBusMethodInvocation *invocation,
> +             gpointer user_data)
> +{
> +    TestServer *h = user_data;
> +    GVariant *var;
> +
> +    var = g_variant_new_fixed_array(G_VARIANT_TYPE_BYTE,
> +                                    h->id->data, h->id->size, sizeof(char));
> +    g_dbus_method_invocation_return_value(invocation,
> +                                          g_variant_new("(@ay)", var));
> +    h->save_called = true;
> +
> +    return TRUE;
> +}
> +
> +static gboolean
> +wait_for_migration_complete(gpointer user_data)
> +{
> +    Test *test = user_data;
> +    QDict *rsp_return;
> +    bool stop = false;
> +    const char *status;
> +
> +    qtest_qmp_send(test->src_qemu, "{ 'execute': 'query-migrate' }");
> +    rsp_return = qtest_qmp_receive_success(test->src_qemu, NULL, NULL);
> +    status = qdict_get_str(rsp_return, "status");
> +    if (g_str_equal(status, "completed") || g_str_equal(status, "failed")) {
> +        stop = true;
> +        g_assert_cmpstr(status, ==,
> +                        test->migrate_fail ? "failed" : "completed");
> +    }
> +    qobject_unref(rsp_return);
> +
> +    if (stop) {
> +        g_main_loop_quit(test->loop);
> +    }
> +    return stop ? G_SOURCE_REMOVE : G_SOURCE_CONTINUE;
> +}
> +
> +static void migrate(QTestState *who, const char *uri)
> +{
> +    QDict *args, *rsp;
> +
> +    args = qdict_new();
> +    qdict_put_str(args, "uri", uri);
> +
> +    rsp = qtest_qmp(who, "{ 'execute': 'migrate', 'arguments': %p }", args);
> +
> +    g_assert(qdict_haskey(rsp, "return"));
> +    qobject_unref(rsp);
> +}
> +
> +typedef struct WaitNamed {
> +    GMainLoop *loop;
> +    bool named;
> +} WaitNamed;
> +
> +static void
> +named_cb(GDBusConnection *connection,
> +         const gchar *name,
> +         gpointer user_data)
> +{
> +    WaitNamed *t = user_data;
> +
> +    t->named = true;
> +    g_main_loop_quit(t->loop);
> +}
> +
> +static GDBusConnection *
> +get_connection(Test *test, guint *ownid)
> +{
> +    g_autofree gchar *addr = NULL;
> +    WaitNamed *wait;
> +    GError *err = NULL;
> +    GDBusConnection *c;
> +
> +    wait = g_new0(WaitNamed, 1);
> +    wait->loop = test->loop;
> +    addr = g_dbus_address_get_for_bus_sync(G_BUS_TYPE_SESSION, NULL, &err);
> +    g_assert_no_error(err);
> +
> +    c = g_dbus_connection_new_for_address_sync(
> +        addr,
> +        G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION |
> +        G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT,
> +        NULL, NULL, &err);
> +    g_assert_no_error(err);
> +    *ownid = g_bus_own_name_on_connection(c, "org.qemu.VMState1",
> +                                          G_BUS_NAME_OWNER_FLAGS_NONE,
> +                                          named_cb, named_cb, wait, g_free);
> +    if (!wait->named) {
> +        g_main_loop_run(wait->loop);
> +    }
> +
> +    return c;
> +}
> +
> +static GDBusObjectManagerServer *
> +get_server(GDBusConnection *conn, TestServer *s, const TestServerId *id)
> +{
> +    g_autoptr(GDBusObjectSkeleton) sk = NULL;
> +    g_autoptr(VMState1Skeleton) v = NULL;
> +    GDBusObjectManagerServer *os;
> +
> +    s->id = id;
> +    os = g_dbus_object_manager_server_new("/org/qemu");
> +    sk = g_dbus_object_skeleton_new("/org/qemu/VMState1");
> +
> +    v = VMSTATE1_SKELETON(vmstate1_skeleton_new());
> +    g_object_set(v, "id", id->name, NULL);
> +
> +    g_signal_connect(v, "handle-load", G_CALLBACK(vmstate_load), s);
> +    g_signal_connect(v, "handle-save", G_CALLBACK(vmstate_save), s);
> +
> +    g_dbus_object_skeleton_add_interface(sk, G_DBUS_INTERFACE_SKELETON(v));
> +    g_dbus_object_manager_server_export(os, sk);
> +    g_dbus_object_manager_server_set_connection(os, conn);
> +
> +    return os;
> +}
> +
> +static void
> +set_id_list(Test *test, QTestState *s)
> +{
> +    if (!test->id_list) {
> +        return;
> +    }
> +
> +    g_assert(!qmp_rsp_is_err(qtest_qmp(s,
> +        "{ 'execute': 'qom-set', 'arguments': "
> +        "{ 'path': '/objects/dv', 'property': 'id-list', 'value': %s } }",
> +        test->id_list)));
> +}
> +static void
> +test_dbus_vmstate(Test *test)
> +{
> +    g_autofree char *src_qemu_args = NULL;
> +    g_autofree char *dst_qemu_args = NULL;
> +    g_autoptr(GTestDBus) srcbus = NULL;
> +    g_autoptr(GTestDBus) dstbus = NULL;
> +    g_autoptr(GDBusConnection) srcconnA = NULL;
> +    g_autoptr(GDBusConnection) srcconnB = NULL;
> +    g_autoptr(GDBusConnection) dstconnA = NULL;
> +    g_autoptr(GDBusConnection) dstconnB = NULL;
> +    g_autoptr(GDBusObjectManagerServer) srcserverA = NULL;
> +    g_autoptr(GDBusObjectManagerServer) srcserverB = NULL;
> +    g_autoptr(GDBusObjectManagerServer) dstserverA = NULL;
> +    g_autoptr(GDBusObjectManagerServer) dstserverB = NULL;
> +    g_auto(GStrv) srcaddr = NULL;
> +    g_auto(GStrv) dstaddr = NULL;
> +    g_autofree char *uri = NULL;
> +    QTestState *src_qemu = NULL, *dst_qemu = NULL;
> +    guint ownsrcA, ownsrcB, owndstA, owndstB;
> +
> +    uri = g_strdup_printf("unix:%s/migsocket", workdir);
> +
> +    test->loop = g_main_loop_new(NULL, TRUE);
> +
> +    srcbus = g_test_dbus_new(G_TEST_DBUS_NONE);
> +    g_test_dbus_up(srcbus);
> +    srcconnA = get_connection(test, &ownsrcA);
> +    srcserverA = get_server(srcconnA, &test->srcA, &idA);
> +    srcconnB = get_connection(test, &ownsrcB);
> +    srcserverB = get_server(srcconnB, &test->srcB, &idB);
> +
> +    /* remove ,guid=foo part */
> +    srcaddr = g_strsplit(g_test_dbus_get_bus_address(srcbus), ",", 2);
> +    src_qemu_args =
> +        g_strdup_printf("-object dbus-vmstate,id=dv,addr=%s", srcaddr[0]);
> +
> +    dstbus = g_test_dbus_new(G_TEST_DBUS_NONE);
> +    g_test_dbus_up(dstbus);
> +    dstconnA = get_connection(test, &owndstA);
> +    dstserverA = get_server(dstconnA, &test->dstA, &idA);
> +    if (!test->without_dst_b) {
> +        dstconnB = get_connection(test, &owndstB);
> +        dstserverB = get_server(dstconnB, &test->dstB, &idB);
> +    }
> +
> +    dstaddr = g_strsplit(g_test_dbus_get_bus_address(dstbus), ",", 2);
> +    dst_qemu_args =
> +        g_strdup_printf("-object dbus-vmstate,id=dv,addr=%s -incoming %s",
> +                        dstaddr[0], uri);
> +
> +    src_qemu = qtest_init(src_qemu_args);
> +    dst_qemu = qtest_init(dst_qemu_args);
> +    set_id_list(test, src_qemu);
> +    set_id_list(test, dst_qemu);
> +
> +    migrate(src_qemu, uri);
> +    test->src_qemu = src_qemu;
> +    g_timeout_add_seconds(1, wait_for_migration_complete, test);
> +
> +    g_main_loop_run(test->loop);
> +    g_main_loop_unref(test->loop);
> +
> +    if (test->migrate_fail) {
> +        qtest_expect_exit_status(dst_qemu, 1);
> +    }
> +    qtest_quit(dst_qemu);
> +    qtest_quit(src_qemu);
> +    g_bus_unown_name(ownsrcA);
> +    g_bus_unown_name(ownsrcB);
> +    g_bus_unown_name(owndstA);
> +    if (!test->without_dst_b) {
> +        g_bus_unown_name(owndstB);
> +    }
> +}
> +
> +static void
> +check_not_migrated(TestServer *s, TestServer *d)
> +{
> +    assert(!s->save_called);
> +    assert(!s->load_called);
> +    assert(!d->save_called);
> +    assert(!d->load_called);
> +}
> +
> +static void
> +check_migrated(TestServer *s, TestServer *d)
> +{
> +    assert(s->save_called);
> +    assert(!s->load_called);
> +    assert(!d->save_called);
> +    assert(d->load_called);
> +}
> +
> +static void
> +test_dbus_vmstate_without_list(void)
> +{
> +    Test test = { 0, };
> +
> +    test_dbus_vmstate(&test);
> +
> +    check_migrated(&test.srcA, &test.dstA);
> +    check_migrated(&test.srcB, &test.dstB);
> +}
> +
> +static void
> +test_dbus_vmstate_with_list(void)
> +{
> +    Test test = { .id_list = "idA,idB" };
> +
> +    test_dbus_vmstate(&test);
> +
> +    check_migrated(&test.srcA, &test.dstA);
> +    check_migrated(&test.srcB, &test.dstB);
> +}
> +
> +static void
> +test_dbus_vmstate_only_a(void)
> +{
> +    Test test = { .id_list = "idA" };
> +
> +    test_dbus_vmstate(&test);
> +
> +    check_migrated(&test.srcA, &test.dstA);
> +    check_not_migrated(&test.srcB, &test.dstB);
> +}
> +
> +static void
> +test_dbus_vmstate_missing_src(void)
> +{
> +    Test test = { .id_list = "idA,idC", .migrate_fail = true };
> +
> +    test_dbus_vmstate(&test);
> +    check_not_migrated(&test.srcA, &test.dstA);
> +    check_not_migrated(&test.srcB, &test.dstB);
> +}
> +
> +static void
> +test_dbus_vmstate_missing_dst(void)
> +{
> +    Test test = { .id_list = "idA,idB",
> +                  .without_dst_b = true,
> +                  .migrate_fail = true };
> +
> +    test_dbus_vmstate(&test);
> +
> +    assert(test.srcA.save_called);
> +    assert(test.srcB.save_called);
> +    assert(!test.dstB.save_called);
> +}
> +
> +int
> +main(int argc, char **argv)
> +{
> +    GError *err = NULL;
> +    g_autofree char *dbus_daemon = NULL;
> +    int ret;
> +
> +    dbus_daemon = g_build_filename(G_STRINGIFY(SRCDIR),
> +                                   "tests",
> +                                   "dbus-vmstate-daemon.sh",
> +                                   NULL);
> +    g_setenv("G_TEST_DBUS_DAEMON", dbus_daemon, true);
> +
> +    g_test_init(&argc, &argv, NULL);
> +
> +    workdir = g_dir_make_tmp("dbus-vmstate-test-XXXXXX", &err);
> +    if (!workdir) {
> +        g_error("Unable to create temporary dir: %s\n", err->message);
> +        exit(1);
> +    }
> +
> +    qtest_add_func("/dbus-vmstate/without-list",
> +                   test_dbus_vmstate_without_list);
> +    qtest_add_func("/dbus-vmstate/with-list",
> +                   test_dbus_vmstate_with_list);
> +    qtest_add_func("/dbus-vmstate/only-a",
> +                   test_dbus_vmstate_only_a);
> +    qtest_add_func("/dbus-vmstate/missing-src",
> +                   test_dbus_vmstate_missing_src);
> +    qtest_add_func("/dbus-vmstate/missing-dst",
> +                   test_dbus_vmstate_missing_dst);
> +
> +    ret = g_test_run();
> +
> +    rmdir(workdir);
> +    g_free(workdir);
> +
> +    return ret;
> +}
> diff --git a/tests/dbus-vmstate1.xml b/tests/dbus-vmstate1.xml
> new file mode 100644
> index 0000000000..cc8563be4c
> --- /dev/null
> +++ b/tests/dbus-vmstate1.xml
> @@ -0,0 +1,12 @@
> +<?xml version="1.0"?>
> +<node name="/" xmlns:doc="http://www.freedesktop.org/dbus/1.0/doc.dtd">
> +  <interface name="org.qemu.VMState1">
> +    <property name="Id" type="s" access="read"/>
> +    <method name="Load">
> +      <arg type="ay" name="data" direction="in"/>
> +    </method>
> +    <method name="Save">
> +      <arg type="ay" name="data" direction="out"/>
> +    </method>
> +  </interface>
> +</node>
> -- 
> 2.23.0
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK