[Qemu-devel] [PATCH 01/11] Add migration capabilities

[Orit Wasserman <owasserm@redhat.com>]

Add migration capabilities that can be queried by the management using
query-migration-supported-capabilities command.
The management can query the source QEMU and the destination QEMU in order to
verify both support some migration capability (currently only XBZRLE).

Signed-off-by: Orit Wasserman <owasserm@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 hmp-commands.hx  |    2 ++
 hmp.c            |   21 +++++++++++++++++++++
 hmp.h            |    1 +
 migration.c      |   12 ++++++++++++
 monitor.c        |    7 +++++++
 qapi-schema.json |   39 +++++++++++++++++++++++++++++++++++++++
 qmp-commands.hx  |   25 +++++++++++++++++++++++++
 7 files changed, 107 insertions(+), 0 deletions(-)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index eea8b32..8267237 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1417,6 +1417,8 @@ show CPU statistics
 show user network stack connection states
 @item info migrate
 show migration status
+@item info migration_supported_capabilities
+show migration supported capabilities
 @item info balloon
 show balloon information
 @item info qtree
diff --git a/hmp.c b/hmp.c
index 6b72a64..2ff71a3 100644
--- a/hmp.c
+++ b/hmp.c
@@ -161,6 +161,27 @@ void hmp_info_migrate(Monitor *mon)
     qapi_free_MigrationInfo(info);
 }
 
+void hmp_info_migration_supported_capabilities(Monitor *mon)
+{
+    MigrationCapabilityStatusList *caps_list, *cap;
+
+    caps_list = qmp_query_migration_supported_capabilities(NULL);
+    if (!caps_list) {
+        monitor_printf(mon, "No supported migration capabilities found\n");
+        return;
+    }
+
+    for (cap = caps_list; cap; cap = cap->next) {
+        monitor_printf(mon, "%s: %s ",
+                       MigrationCapability_lookup[cap->value->capability],
+                       cap->value->state ? "on" : "off");
+    }
+
+    monitor_printf(mon, "\n");
+
+    qapi_free_MigrationCapabilityStatusList(caps_list);
+}
+
 void hmp_info_cpus(Monitor *mon)
 {
     CpuInfoList *cpu_list, *cpu;
diff --git a/hmp.h b/hmp.h
index 8d2b0d7..8442c22 100644
--- a/hmp.h
+++ b/hmp.h
@@ -25,6 +25,7 @@ void hmp_info_uuid(Monitor *mon);
 void hmp_info_chardev(Monitor *mon);
 void hmp_info_mice(Monitor *mon);
 void hmp_info_migrate(Monitor *mon);
+void hmp_info_migration_supported_capabilities(Monitor *mon);
 void hmp_info_cpus(Monitor *mon);
 void hmp_info_block(Monitor *mon);
 void hmp_info_blockstats(Monitor *mon);
diff --git a/migration.c b/migration.c
index 8db1b43..35444f7 100644
--- a/migration.c
+++ b/migration.c
@@ -166,6 +166,18 @@ MigrationInfo *qmp_query_migrate(Error **errp)
     return info;
 }
 
+MigrationCapabilityStatusList *
+qmp_query_migration_supported_capabilities(Error **errp)
+{
+    MigrationCapabilityStatusList *caps_list = g_malloc0(sizeof(*caps_list));
+
+    caps_list->value = g_malloc(sizeof(*caps_list->value));
+    caps_list->value->capability = MIGRATION_CAPABILITY_XBZRLE;
+    caps_list->next = NULL;
+
+    return caps_list;
+}
+
 /* shared migration helpers */
 
 static int migrate_fd_cleanup(MigrationState *s)
diff --git a/monitor.c b/monitor.c
index 09aa3cd..43f7df5 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2662,6 +2662,13 @@ static mon_cmd_t info_cmds[] = {
         .mhandler.info = hmp_info_migrate,
     },
     {
+        .name       = "migration_supported_capabilities",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show migration supported capabilities",
+        .mhandler.info = hmp_info_migration_supported_capabilities,
+    },
+    {
         .name       = "balloon",
         .args_type  = "",
         .params     = "",
diff --git a/qapi-schema.json b/qapi-schema.json
index a92adb1..68d0fbb 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -306,6 +306,45 @@
 { 'command': 'query-migrate', 'returns': 'MigrationInfo' }
 
 ##
+# @MigrationCapability
+#
+# Migration capabilities enumeration
+#
+# @xbzrle: Migration supports xbzrle (Xor Based Zero Run Length Encoding).
+#          This feature allows us to minimize migration traffic for certain work
+#          loads, by sending compressed difference of the pages
+#
+# Since: 1.2
+##
+{ 'enum': 'MigrationCapability',
+  'data': ['xbzrle'] }
+
+##
+# @MigrationCapabilityStatus
+#
+# Migration capability information
+#
+# @capability: capability enum
+#
+# @state: capability state bool
+#
+# Since: 1.2
+##
+{ 'type': 'MigrationCapabilityStatus',
+  'data': { 'capability' : 'MigrationCapability', 'state' : 'bool' } }
+
+##
+# @query-migration-supported-capabilities
+#
+# Returns information about current migration process capabilities.
+#
+# Returns: @MigrationCapabilityStatus list
+#
+# Since: 1.2
+##
+{ 'command': 'query-migration-supported-capabilities', 'returns': ['MigrationCapabilityStatus'] }
+
+##
 # @MouseInfo:
 #
 # Information about a mouse device.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index e3cf3c5..16fbcef 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -2141,6 +2141,31 @@ EQMP
     },
 
 SQMP
+query-migration-supported-capabilities
+-------
+
+Query migration supported capabilities
+
+- "xbzrle": xbzrle support
+
+Arguments:
+
+Example:
+
+-> { "execute": "query-migration-supported-capabilities"}
+<- { "return": [ { "capability": "xbzrle", "state": true },
+                 { "capability": "foobar", "state": false } ] }
+
+EQMP
+
+    {
+        .name       = "query-migration-supported-capabilities",
+        .args_type  = "",
+	.mhandler.cmd_new =
+            qmp_marshal_input_query_migration_supported_capabilities,
+    },
+
+SQMP
 query-balloon
 -------------
 
-- 
1.7.7.6