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>

7 files changed, 74 insertions, 3 deletions

diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index 7c6dfab..b9179e8 100644
--- a/hw/core/qdev-properties-system.c
+++ b/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 --- */
 
 /*
diff --git a/include/hw/qdev-properties-system.h b/include/hw/qdev-properties-system.h
index e4f8a13..91f7a24 100644
--- a/include/hw/qdev-properties-system.h
+++ b/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)
diff --git a/include/migration/misc.h b/include/migration/misc.h
index 673ac49..1bc8902 100644
--- a/include/migration/misc.h
+++ b/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 */
diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
index dfe98da..a170440 100644
--- a/migration/migration-hmp-cmds.c
+++ b/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);
     }
diff --git a/migration/options.c b/migration/options.c
index 9a39826..8d8ec73 100644
--- a/migration/options.c
+++ b/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)
diff --git a/migration/options.h b/migration/options.h
index 237f2d6..246c160 100644
--- a/migration/options.h
+++ b/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);
diff --git a/qapi/migration.json b/qapi/migration.json
index e6610af..47c02a9 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -632,6 +632,15 @@
             { 'name': 'zstd', 'if': 'CONFIG_ZSTD' } ] }
 
 ##
+# @MigMode:
+#
+# @normal: the original form of migration. (since 8.2)
+#
+##
+{ 'enum': 'MigMode',
+  'data': [ 'normal' ] }
+
+##
 # @BitmapMigrationBitmapAliasTransform:
 #
 # @persistent: If present, the bitmap will be made persistent or
@@ -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: