migration: mode parameter

Create a mode migration parameter that can be used to select alternate
migration algorithms.  The default mode is normal, representing the
current migration algorithm, and does not need to be explicitly set.

No functional change until a new mode is added, except that the mode is
shown by the 'info migrate' command.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1698263069-406971-2-git-send-email-steven.sistare@oracle.com>

hw/core/qdev-properties-system.c

@@ -673,6 +673,20 @@ const PropertyInfo qdev_prop_multifd_compression = {
     .set_default_value = qdev_propinfo_set_default_value_enum,
 };
 
+/* --- MigMode --- */
+
+QEMU_BUILD_BUG_ON(sizeof(MigMode) != sizeof(int));
+
+const PropertyInfo qdev_prop_mig_mode = {
+    .name = "MigMode",
+    .description = "mig_mode values, "
+                   "normal",
+    .enum_table = &MigMode_lookup,
+    .get = qdev_propinfo_get_enum,
+    .set = qdev_propinfo_set_enum,
+    .set_default_value = qdev_propinfo_set_default_value_enum,
+};
+
 /* --- Reserved Region --- */
 
 /*

include/hw/qdev-properties-system.h

@@ -7,6 +7,7 @@ extern const PropertyInfo qdev_prop_chr;
 extern const PropertyInfo qdev_prop_macaddr;
 extern const PropertyInfo qdev_prop_reserved_region;
 extern const PropertyInfo qdev_prop_multifd_compression;
+extern const PropertyInfo qdev_prop_mig_mode;
 extern const PropertyInfo qdev_prop_losttickpolicy;
 extern const PropertyInfo qdev_prop_blockdev_on_error;
 extern const PropertyInfo qdev_prop_bios_chs_trans;
@@ -42,6 +43,9 @@ extern const PropertyInfo qdev_prop_cpus390entitlement;
 #define DEFINE_PROP_MULTIFD_COMPRESSION(_n, _s, _f, _d) \
     DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_multifd_compression, \
                        MultiFDCompression)
+#define DEFINE_PROP_MIG_MODE(_n, _s, _f, _d) \
+    DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_mig_mode, \
+                       MigMode)
 #define DEFINE_PROP_LOSTTICKPOLICY(_n, _s, _f, _d) \
     DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_losttickpolicy, \
                         LostTickPolicy)

include/migration/misc.h

@@ -15,6 +15,7 @@
 #define MIGRATION_MISC_H
 
 #include "qemu/notify.h"
+#include "qapi/qapi-types-migration.h"
 #include "qapi/qapi-types-net.h"
 
 /* migration/ram.c */

migration/migration-hmp-cmds.c

@@ -387,6 +387,11 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
         monitor_printf(mon, "%s: %" PRIu64 " MB/s\n",
             MigrationParameter_str(MIGRATION_PARAMETER_VCPU_DIRTY_LIMIT),
             params->vcpu_dirty_limit);
+
+        assert(params->has_mode);
+        monitor_printf(mon, "%s: %s\n",
+            MigrationParameter_str(MIGRATION_PARAMETER_MODE),
+            qapi_enum_lookup(&MigMode_lookup, params->mode));
     }
 
     qapi_free_MigrationParameters(params);
@@ -661,6 +666,10 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
         p->has_vcpu_dirty_limit = true;
         visit_type_size(v, param, &p->vcpu_dirty_limit, &err);
         break;
+    case MIGRATION_PARAMETER_MODE:
+        p->has_mode = true;
+        visit_type_MigMode(v, param, &p->mode, &err);
+        break;
     default:
         assert(0);
     }

migration/options.c

@@ -176,6 +176,9 @@ Property migration_properties[] = {
     DEFINE_PROP_UINT64("vcpu-dirty-limit", MigrationState,
                        parameters.vcpu_dirty_limit,
                        DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT),
+    DEFINE_PROP_MIG_MODE("mode", MigrationState,
+                      parameters.mode,
+                      MIG_MODE_NORMAL),
 
     /* Migration capabilities */
     DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),
@@ -827,6 +830,13 @@ uint64_t migrate_max_postcopy_bandwidth(void)
     return s->parameters.max_postcopy_bandwidth;
 }
 
+MigMode migrate_mode(void)
+{
+    MigrationState *s = migrate_get_current();
+
+    return s->parameters.mode;
+}
+
 int migrate_multifd_channels(void)
 {
     MigrationState *s = migrate_get_current();
@@ -999,6 +1009,8 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
     params->x_vcpu_dirty_limit_period = s->parameters.x_vcpu_dirty_limit_period;
     params->has_vcpu_dirty_limit = true;
     params->vcpu_dirty_limit = s->parameters.vcpu_dirty_limit;
+    params->has_mode = true;
+    params->mode = s->parameters.mode;
 
     return params;
 }
@@ -1034,6 +1046,7 @@ void migrate_params_init(MigrationParameters *params)
     params->has_announce_step = true;
     params->has_x_vcpu_dirty_limit_period = true;
     params->has_vcpu_dirty_limit = true;
+    params->has_mode = true;
 }
 
 /*
@@ -1331,6 +1344,10 @@ static void migrate_params_test_apply(MigrateSetParameters *params,
     if (params->has_vcpu_dirty_limit) {
         dest->vcpu_dirty_limit = params->vcpu_dirty_limit;
     }
+
+    if (params->has_mode) {
+        dest->mode = params->mode;
+    }
 }
 
 static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
@@ -1471,6 +1488,10 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
     if (params->has_vcpu_dirty_limit) {
         s->parameters.vcpu_dirty_limit = params->vcpu_dirty_limit;
     }
+
+    if (params->has_mode) {
+        s->parameters.mode = params->mode;
+    }
 }
 
 void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)

migration/options.h

@@ -83,6 +83,7 @@ uint8_t migrate_max_cpu_throttle(void);
 uint64_t migrate_max_bandwidth(void);
 uint64_t migrate_avail_switchover_bandwidth(void);
 uint64_t migrate_max_postcopy_bandwidth(void);
+MigMode migrate_mode(void);
 int migrate_multifd_channels(void);
 MultiFDCompression migrate_multifd_compression(void);
 int migrate_multifd_zlib_level(void);

qapi/migration.json

@@ -631,6 +631,15 @@
   'data': [ 'none', 'zlib',
             { 'name': 'zstd', 'if': 'CONFIG_ZSTD' } ] }
 
+##
+# @MigMode:
+#
+# @normal: the original form of migration. (since 8.2)
+#
+##
+{ 'enum': 'MigMode',
+  'data': [ 'normal' ] }
+
 ##
 # @BitmapMigrationBitmapAliasTransform:
 #
@@ -849,6 +858,9 @@
 # @vcpu-dirty-limit: Dirtyrate limit (MB/s) during live migration.
 #     Defaults to 1.  (Since 8.1)
 #
+# @mode: Migration mode. See description in @MigMode. Default is 'normal'.
+#        (Since 8.2)
+#
 # Features:
 #
 # @deprecated: Member @block-incremental is deprecated.  Use
@@ -881,7 +893,8 @@
            'multifd-zlib-level', 'multifd-zstd-level',
            'block-bitmap-mapping',
            { 'name': 'x-vcpu-dirty-limit-period', 'features': ['unstable'] },
-           'vcpu-dirty-limit'] }
+           'vcpu-dirty-limit',
+           'mode'] }
 
 ##
 # @MigrateSetParameters:
@@ -1033,6 +1046,9 @@
 # @vcpu-dirty-limit: Dirtyrate limit (MB/s) during live migration.
 #     Defaults to 1.  (Since 8.1)
 #
+# @mode: Migration mode. See description in @MigMode. Default is 'normal'.
+#        (Since 8.2)
+#
 # Features:
 #
 # @deprecated: Member @block-incremental is deprecated.  Use
@@ -1085,7 +1101,8 @@
             '*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ],
             '*x-vcpu-dirty-limit-period': { 'type': 'uint64',
                                             'features': [ 'unstable' ] },
-            '*vcpu-dirty-limit': 'uint64'} }
+            '*vcpu-dirty-limit': 'uint64',
+            '*mode': 'MigMode'} }
 
 ##
 # @migrate-set-parameters:
@@ -1257,6 +1274,9 @@
 # @vcpu-dirty-limit: Dirtyrate limit (MB/s) during live migration.
 #     Defaults to 1.  (Since 8.1)
 #
+# @mode: Migration mode. See description in @MigMode. Default is 'normal'.
+#        (Since 8.2)
+#
 # Features:
 #
 # @deprecated: Member @block-incremental is deprecated.  Use
@@ -1306,7 +1326,8 @@
             '*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ],
             '*x-vcpu-dirty-limit-period': { 'type': 'uint64',
                                             'features': [ 'unstable' ] },
-            '*vcpu-dirty-limit': 'uint64'} }
+            '*vcpu-dirty-limit': 'uint64',
+            '*mode': 'MigMode'} }
 
 ##
 # @query-migrate-parameters: