spice/vnc: client migration.

Handle spice client migration, i.e. inform a spice client connected
about the new host and connection parameters, so it can move over the
connection automatically.

The monitor command has a not-yet used protocol argument simliar to
set_password and expire_password commands.  This allows to add a simliar
feature to vnc in the future.  Daniel Berrange plans to work on this.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

hmp-commands.hx

@@ -814,6 +814,23 @@ ETEXI
         .mhandler.cmd_new = do_snapshot_blkdev,
     },
 
+STEXI
+@item client_migrate_info @var{protocol} @var{hostname} @var{port} @var{tls-port} @var{cert-subject}
+@findex client_migrate_info
+Set the spice/vnc connection info for the migration target.  The spice/vnc
+server will ask the spice/vnc client to automatically reconnect using the
+new parameters (if specified) once the vm migration finished successfully.
+ETEXI
+
+    {
+        .name       = "client_migrate_info",
+        .args_type  = "protocol:s,hostname:s,port:i?,tls-port:i?,cert-subject:s?",
+        .params     = "protocol hostname port tls-port cert-subject",
+        .help       = "send migration info to spice/vnc client",
+        .user_print = monitor_user_noop,
+        .mhandler.cmd_new = client_migrate_info,
+    },
+
 STEXI
 @item snapshot_blkdev
 @findex snapshot_blkdev

monitor.c

@@ -1173,6 +1173,33 @@ static int expire_password(Monitor *mon, const QDict *qdict, QObject **ret_data)
     return -1;
 }
 
+static int client_migrate_info(Monitor *mon, const QDict *qdict, QObject **ret_data)
+{
+    const char *protocol = qdict_get_str(qdict, "protocol");
+    const char *hostname = qdict_get_str(qdict, "hostname");
+    const char *subject  = qdict_get_try_str(qdict, "cert-subject");
+    int port             = qdict_get_try_int(qdict, "port", -1);
+    int tls_port         = qdict_get_try_int(qdict, "tls-port", -1);
+    int ret;
+
+    if (strcmp(protocol, "spice") == 0) {
+        if (!using_spice) {
+            qerror_report(QERR_DEVICE_NOT_ACTIVE, "spice");
+            return -1;
+        }
+
+        ret = qemu_spice_migrate_info(hostname, port, tls_port, subject);
+        if (ret != 0) {
+            qerror_report(QERR_UNDEFINED_ERROR);
+            return -1;
+        }
+        return 0;
+    }
+
+    qerror_report(QERR_INVALID_PARAMETER, "protocol");
+    return -1;
+}
+
 static int do_screen_dump(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     vga_hw_screen_dump(qdict_get_str(qdict, "filename"));

qmp-commands.hx

@@ -502,6 +502,41 @@ EQMP
         .mhandler.cmd_new = do_migrate_set_speed,
     },
 
+SQMP
+client_migrate_info
+------------------
+
+Set the spice/vnc connection info for the migration target.  The spice/vnc
+server will ask the spice/vnc client to automatically reconnect using the
+new parameters (if specified) once the vm migration finished successfully.
+
+Arguments:
+
+- "protocol":     protocol: "spice" or "vnc" (json-string)
+- "hostname":     migration target hostname (json-string)
+- "port":         spice/vnc tcp port for plaintext channels (json-int, optional)
+- "tls-port":     spice tcp port for tls-secured channels (json-int, optional)
+- "cert-subject": server certificate subject (json-string, optional)
+
+Example:
+
+-> { "execute": "client_migrate_info",
+     "arguments": { "protocol": "spice",
+                    "hostname": "virt42.lab.kraxel.org",
+                    "port": 1234 } }
+<- { "return": {} }
+
+EQMP
+
+    {
+        .name       = "client_migrate_info",
+        .args_type  = "protocol:s,hostname:s,port:i?,tls-port:i?,cert-subject:s?",
+        .params     = "protocol hostname port tls-port cert-subject",
+        .help       = "send migration info to spice/vnc client",
+        .user_print = monitor_user_noop,
+        .mhandler.cmd_new = client_migrate_info,
+    },
+
 SQMP
 migrate_set_speed
 -----------------

ui/qemu-spice.h

@@ -35,6 +35,8 @@ int qemu_spice_add_interface(SpiceBaseInstance *sin);
 int qemu_spice_set_passwd(const char *passwd,
                           bool fail_if_connected, bool disconnect_if_connected);
 int qemu_spice_set_pw_expire(time_t expires);
+int qemu_spice_migrate_info(const char *hostname, int port, int tls_port,
+                            const char *subject);
 
 void do_info_spice_print(Monitor *mon, const QObject *data);
 void do_info_spice(Monitor *mon, QObject **ret_data);
@@ -44,6 +46,8 @@ void do_info_spice(Monitor *mon, QObject **ret_data);
 #define using_spice 0
 #define qemu_spice_set_passwd(_p, _f1, _f2) (-1)
 #define qemu_spice_set_pw_expire(_e) (-1)
+static inline int qemu_spice_migrate_info(const char *h, int p, int t, const char *s)
+{ return -1; }
 
 #endif /* CONFIG_SPICE */
 

ui/spice-core.c

@@ -30,11 +30,15 @@
 #include "qbool.h"
 #include "qstring.h"
 #include "qjson.h"
+#include "notify.h"
+#include "migration.h"
 #include "monitor.h"
+#include "hw/hw.h"
 
 /* core bits */
 
 static SpiceServer *spice_server;
+static Notifier migration_state;
 static const char *auth = "spice";
 static char *auth_passwd;
 static time_t auth_expires = TIME_MAX;
@@ -416,6 +420,24 @@ void do_info_spice(Monitor *mon, QObject **ret_data)
     *ret_data = QOBJECT(server);
 }
 
+static void migration_state_notifier(Notifier *notifier)
+{
+    int state = get_migration_state();
+
+    if (state == MIG_STATE_COMPLETED) {
+#if SPICE_SERVER_VERSION >= 0x000701 /* 0.7.1 */
+        spice_server_migrate_switch(spice_server);
+#endif
+    }
+}
+
+int qemu_spice_migrate_info(const char *hostname, int port, int tls_port,
+                            const char *subject)
+{
+    return spice_server_migrate_info(spice_server, hostname,
+                                     port, tls_port, subject);
+}
+
 static int add_channel(const char *name, const char *value, void *opaque)
 {
     int security = 0;
@@ -573,6 +595,9 @@ void qemu_spice_init(void)
     spice_server_init(spice_server, &core_interface);
     using_spice = 1;
 
+    migration_state.notify = migration_state_notifier;
+    add_migration_state_change_notifier(&migration_state);
+
     qemu_spice_input_init();
     qemu_spice_audio_init();