Index: lldb/include/lldb/Host/common/NativeProcessProtocol.h
===================================================================
--- lldb/include/lldb/Host/common/NativeProcessProtocol.h
+++ lldb/include/lldb/Host/common/NativeProcessProtocol.h
@@ -30,6 +30,8 @@
 #include <vector>
 
 namespace lldb_private {
+LLVM_ENABLE_BITMASK_ENUMS_IN_NAMESPACE();
+
 class MemoryRegionInfo;
 class ResumeActionList;
 
@@ -258,6 +260,14 @@
   virtual Status GetFileLoadAddress(const llvm::StringRef &file_name,
                                     lldb::addr_t &load_addr) = 0;
 
+  /// Extension flag constants, passed to SetEnabledExtension().
+  enum class Extension {
+    fork = (1u << 0),
+    vfork = (1u << 1),
+
+    LLVM_MARK_AS_BITMASK_ENUM(vfork)
+  };
+
   class Factory {
   public:
     virtual ~Factory();
@@ -304,6 +314,14 @@
     virtual llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
     Attach(lldb::pid_t pid, NativeDelegate &native_delegate,
            MainLoop &mainloop) const = 0;
+
+    /// Get the bitmask of extensions supported by this process plugin.
+    ///
+    /// \return
+    ///     A NativeProcessProtocol::Extension bitmask.
+    virtual Extension GetSupportedExtensions() const {
+      return {};
+    }
   };
 
   /// Start tracing a process or its threads.
@@ -358,6 +376,19 @@
     return llvm::make_error<UnimplementedError>();
   }
 
+  /// Method called in order to propagate the bitmap of protocol
+  /// extensions supported by the client.
+  ///
+  /// \param[in] flags
+  ///     The bitmap of enabled extensions.
+  ///
+  /// \return An error if extension-related setup failed, success
+  /// otherwise.
+  virtual llvm::Error SetEnabledExtensions(Extension flags) {
+    m_enabled_extensions = flags;
+    return llvm::Error::success();
+  }
+
 protected:
   struct SoftwareBreakpoint {
     uint32_t ref_count;
@@ -388,6 +419,9 @@
   // stopping it.
   llvm::DenseSet<int> m_signals_to_ignore;
 
+  // Extensions enabled per the last SetEnabledExtensions() call.
+  Extension m_enabled_extensions;
+
   // lldb_private::Host calls should be used to launch a process for debugging,
   // and then the process should be attached to. When attaching to a process
   // lldb_private::Host calls should be used to locate the process to attach
Index: lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py
+++ lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py
@@ -904,6 +904,8 @@
         "qEcho",
         "QPassSignals",
         "multiprocess",
+        "fork-events",
+        "vfork-events",
     ]
 
     def parse_qSupported_response(self, context):
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
@@ -353,7 +353,9 @@
 
   // build the qSupported packet
   std::vector<std::string> features = {"xmlRegisters=i386,arm,mips,arc",
-                                       "multiprocess+"};
+                                       "multiprocess+",
+                                       "fork-events+",
+                                       "vfork-events+"};
   StreamString packet;
   packet.PutCString("qSupported");
   for (uint32_t i = 0; i < features.size(); ++i) {
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
@@ -99,6 +99,9 @@
   uint32_t m_next_saved_registers_id = 1;
   bool m_handshake_completed = false;
 
+  bool m_fork_events_supported = false;
+  bool m_vfork_events_supported = false;
+
   PacketResult SendONotification(const char *buffer, uint32_t len);
 
   PacketResult SendWResponse(NativeProcessProtocol *process);
@@ -256,6 +259,9 @@
   llvm::Expected<lldb::tid_t> ReadTid(StringExtractorGDBRemote &packet,
                                       bool allow_all = false);
 
+  // Call SetEnabledExtensions() with appropriate flags on the process.
+  void SetEnabledExtensions(NativeProcessProtocol& process);
+
   // For GDBRemoteCommunicationServerLLGS only
   GDBRemoteCommunicationServerLLGS(const GDBRemoteCommunicationServerLLGS &) =
       delete;
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -251,6 +251,8 @@
     m_debugged_process_up = std::move(*process_or);
   }
 
+  SetEnabledExtensions(*m_debugged_process_up);
+
   // Handle mirroring of inferior stdout/stderr over the gdb-remote protocol as
   // needed. llgs local-process debugging may specify PTY paths, which will
   // make these file actions non-null process launch -i/e/o will also make
@@ -318,6 +320,7 @@
     return status;
   }
   m_debugged_process_up = std::move(*process_or);
+  SetEnabledExtensions(*m_debugged_process_up);
 
   // Setup stdout/stderr mapping from inferior.
   auto terminal_fd = m_debugged_process_up->GetTerminalFileDescriptor();
@@ -3545,5 +3548,49 @@
         "QPassSignals+", "qXfer:auxv:read+", "qXfer:libraries-svr4:read+",
 #endif
   });
+
+  // check for platform features
+  auto process_features = m_process_factory.GetSupportedExtensions();
+
+  // reset to defaults
+  m_fork_events_supported = false;
+  m_vfork_events_supported = false;
+
+  // check for client features
+  for (auto x : client_features) {
+    if (x == "fork-events+" &&
+        (process_features & NativeProcessProtocol::Extension::fork) ==
+            NativeProcessProtocol::Extension::fork)
+      m_fork_events_supported = true;
+    else if (x == "vfork-events+" &&
+             (process_features & NativeProcessProtocol::Extension::vfork) ==
+                 NativeProcessProtocol::Extension::vfork)
+      m_vfork_events_supported = true;
+  }
+
+  // report only if actually supported
+  if (m_fork_events_supported)
+    ret.push_back("fork-events+");
+  if (m_vfork_events_supported)
+    ret.push_back("vfork-events+");
+
+  if (m_debugged_process_up)
+    SetEnabledExtensions(*m_debugged_process_up);
   return ret;
 }
+
+void GDBRemoteCommunicationServerLLGS::SetEnabledExtensions(
+    NativeProcessProtocol &process) {
+  Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PROCESS));
+
+  NativeProcessProtocol::Extension flags;
+  if (m_fork_events_supported)
+    flags |= NativeProcessProtocol::Extension::fork;
+  if (m_vfork_events_supported)
+    flags |= NativeProcessProtocol::Extension::vfork;
+
+  llvm::Error error = process.SetEnabledExtensions(flags);
+  if (error)
+    LLDB_LOG_ERROR(log, std::move(error),
+                   "Enabling protocol extensions failed: {0}");
+}