Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -1547,14 +1547,16 @@
     }
   }
 
-  if (pid != LLDB_INVALID_PROCESS_ID) {
-    if (!m_supports_multiprocess) {
-      error.SetErrorString(
-          "Multiprocess extension not supported by the server.");
-      return error;
-    }
+  if (m_supports_multiprocess) {
+    // Some servers (e.g. qemu) require specifying the PID even if only a single
+    // process is running.
+    if (pid == LLDB_INVALID_PROCESS_ID)
+      pid = GetCurrentProcessID();
     packet.PutChar(';');
     packet.PutHex64(pid);
+  } else if (pid != LLDB_INVALID_PROCESS_ID) {
+    error.SetErrorString("Multiprocess extension not supported by the server.");
+    return error;
   }
 
   StringExtractorGDBRemote response;