[v6,09/11] Add set_cachesize command

diff --git a/hmp-commands.hx b/hmp-commands.hx
index e6506fc..3b7255d 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -776,6 +776,21 @@  STEXI
 @item migrate_cancel
 @findex migrate_cancel
 Cancel the current VM migration.
+
+ETEXI
+
+    {
+        .name       = "migrate_set_cachesize",
+        .args_type  = "value:o",
+        .params     = "value",
+        .help       = "set cache size (in MB) for XBZRLE migrations",
+        .mhandler.cmd = hmp_migrate_set_cachesize,
+    },
+
+STEXI
+@item migrate_set_cachesize @var{value}
+@findex migrate_set_cache
+Set cache size to @var{value} (in MB) for xbzrle migrations.
 ETEXI
 
     {
diff --git a/hmp.c b/hmp.c
index 9c41e50..9871292 100644
--- a/hmp.c
+++ b/hmp.c
@@ -694,6 +694,19 @@  void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict)
     qmp_migrate_set_downtime(value, NULL);
 }
 
+void hmp_migrate_set_cachesize(Monitor *mon, const QDict *qdict)
+{
+    int64_t value = qdict_get_int(qdict, "value");
+    Error *err = NULL;
+
+    qmp_migrate_set_cachesize(value, &err);
+    if (err) {
+        monitor_printf(mon, "%s\n", error_get_pretty(err));
+        error_free(err);
+        return;
+    }
+}
+
 void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict)
 {
     int64_t value = qdict_get_int(qdict, "value");
diff --git a/hmp.h b/hmp.h
index fdb5b24..ad9f8db 100644
--- a/hmp.h
+++ b/hmp.h
@@ -50,6 +50,7 @@  void hmp_snapshot_blkdev(Monitor *mon, const QDict *qdict);
 void hmp_migrate_cancel(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict);
+void hmp_migrate_set_cachesize(Monitor *mon, const QDict *qdict);
 void hmp_set_password(Monitor *mon, const QDict *qdict);
 void hmp_expire_password(Monitor *mon, const QDict *qdict);
 void hmp_eject(Monitor *mon, const QDict *qdict);
diff --git a/migration.c b/migration.c
index b2bb638..1cca73f 100644
--- a/migration.c
+++ b/migration.c
@@ -166,7 +166,7 @@  MigrationCapList *qmp_query_migration_caps(Error **errp)
     MigrationCapList *caps_list = g_malloc0(sizeof(*caps_list));
 
     caps_list->value = g_malloc(sizeof(*caps_list->value));
-    caps_list->value->name = g_strdup("uleb");
+    caps_list->value->name = g_strdup("xbzrle");
     caps_list->next = NULL;
 
     return caps_list;
@@ -494,6 +494,26 @@  void qmp_migrate_cancel(Error **errp)
     migrate_fd_cancel(migrate_get_current());
 }
 
+void qmp_migrate_set_cachesize(int64_t value, Error **errp)
+{
+    /* On 32-bit hosts, QEMU is limited by virtual address space */
+    if (value > (2047 << 20) && HOST_LONG_BITS == 32) {
+        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
+                  "exceeding address space");
+        return;
+    }
+
+    /* power of 2 */
+    if (value != 1 && (value & (value - 1))) {
+        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
+                  "needs to be power of 2");
+        return;
+    }
+
+    value = MIN(UINT64_MAX, value);
+    migrate_cache_size =  value;
+}
+
 void qmp_migrate_set_speed(int64_t value, Error **errp)
 {
     MigrationState *s;
diff --git a/migration.h b/migration.h
index 7e1c7c0..4e53760 100644
--- a/migration.h
+++ b/migration.h
@@ -111,4 +111,6 @@  int decode_page(uint8_t *src, int slen, uint8_t *dst, int dlen);
 
 void arch_set_params(const MigrationParams *params, void *opaque);
 
+void do_migrate_set_cachesize(Monitor *mon, const QDict *qdict);
+
 #endif
diff --git a/qapi-schema.json b/qapi-schema.json
index 060b7e6..cb057d5 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1197,6 +1197,19 @@ 
 { 'command': 'migrate_set_speed', 'data': {'value': 'int'} }
 
 ##
+# @migrate_set_cachesize
+#
+# Set XBZRLE cache size
+#
+# @value: cache size in Mbytes
+#
+# Returns: nothing on success
+#
+# Since: 1.1
+##
+{ 'command': 'migrate_set_cachesize', 'data': {'value': 'int'} }
+
+##
 # @DevicePropertyInfo:
 #
 # @name: the name of the property
diff --git a/qmp-commands.hx b/qmp-commands.hx
index e07d2c2..ad4e328 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -482,6 +482,28 @@  Example:
 <- { "return": {} }
 
 EQMP
+{
+        .name       = "migrate_set_cachesize",
+        .args_type  = "value:o",
+        .mhandler.cmd_new = qmp_marshal_input_migrate_set_cachesize,
+    },
+
+SQMP
+migrate_set_cachesize
+---------------------
+
+Set cache size to be used by XBZRLE migration
+
+Arguments:
+
+- "value": cache size in bytes (json-int)
+
+Example:
+
+-> { "execute": "migrate_set_cachesize", "arguments": { "value": 512 } }
+<- { "return": {} }
+
+EQMP
 
     {
         .name       = "migrate_set_speed",