[Memory, D3D12] Various refactoring from data provider development

src/xenia/cpu/mmio_handler.h

@@ -11,6 +11,7 @@
 #define XENIA_CPU_MMIO_HANDLER_H_
 
 #include <memory>
+#include <mutex>
 #include <vector>
 
 #include "xenia/base/mutex.h"
@@ -44,12 +45,13 @@ class MMIOHandler {
 
   typedef uint32_t (*HostToGuestVirtual)(const void* context,
                                          const void* host_address);
-  typedef bool (*AccessViolationCallback)(void* context, void* host_address,
-                                          bool is_write);
+  typedef bool (*AccessViolationCallback)(
+      std::unique_lock<std::recursive_mutex> global_lock_locked_once,
+      void* context, void* host_address, bool is_write);
 
-  // access_violation_callback is called in global_critical_region, so if
-  // multiple threads trigger an access violation in the same page, the callback
-  // will be called only once.
+  // access_violation_callback is called with global_critical_region locked once
+  // on the thread, so if multiple threads trigger an access violation in the
+  // same page, the callback will be called only once.
   static std::unique_ptr<MMIOHandler> Install(
       uint8_t* virtual_membase, uint8_t* physical_membase, uint8_t* membase_end,
       HostToGuestVirtual host_to_guest_virtual,