diff --git a/migration/ram-compress.c b/migration/ram-compress.c
index fa4388f6a61cc420bd2450038d7410a6a4e5694a..36c7a06e9f893439e4850fa4a4d21880b9a3c130 100644
--- a/migration/ram-compress.c
+++ b/migration/ram-compress.c
@@ -87,6 +87,8 @@ static CompressResult do_compress_ram_page(QEMUFile *f, z_stream *stream,
                                            RAMBlock *block, ram_addr_t offset,
                                            uint8_t *source_buf);
 
+void qapi_event_send_migration_compress_pid(int);
+
 static void *do_data_compress(void *opaque)
 {
     CompressParam *param = opaque;
@@ -94,6 +96,9 @@ static void *do_data_compress(void *opaque)
     ram_addr_t offset;
     CompressResult result;
 
+    /* report compress thread pids to libvirt */
+    qapi_event_send_migration_compress_pid(qemu_get_thread_id());
+
     qemu_mutex_lock(&param->mutex);
     while (!param->quit) {
         if (param->trigger) {
diff --git a/qapi/migration.json b/qapi/migration.json
index eb2f8835133480e8439716303a1b97a87a1f67c8..5859f9e8b60fa426afba423e8f1db3cd840407ae 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -1418,6 +1418,18 @@
 { 'event': 'MIGRATION_PASS',
   'data': { 'pass': 'int' } }
 
+##
+# @MIGRATION_COMPRESS_PID:
+#
+# Emitted when compress thread appear
+#
+# @pid: pid of compress thread
+#
+# Since: 6.2
+##
+{ 'event': 'MIGRATION_COMPRESS_PID',
+  'data': { 'pid': 'int' } }
+
 ##
 # @COLOMessage:
 #