diff --git a/src/mem/ruby/system/RubyPort.cc b/src/mem/ruby/system/RubyPort.cc
index d1c306bb29..305228a8fc 100644
--- a/src/mem/ruby/system/RubyPort.cc
+++ b/src/mem/ruby/system/RubyPort.cc
@@ -370,3 +370,9 @@ RubyPort::M5Port::isPhysMemAddress(Addr addr)
     }
     return false;
 }
+
+unsigned
+RubyPort::M5Port::deviceBlockSize() const
+{
+    return (unsigned) RubySystem::getBlockSizeBytes();
+}
diff --git a/src/mem/ruby/system/RubyPort.hh b/src/mem/ruby/system/RubyPort.hh
index 56701cd5c3..a2316781ae 100644
--- a/src/mem/ruby/system/RubyPort.hh
+++ b/src/mem/ruby/system/RubyPort.hh
@@ -36,6 +36,7 @@
 #include "mem/physical.hh"
 #include "mem/protocol/RequestStatus.hh"
 #include "mem/ruby/libruby.hh"
+#include "mem/ruby/system/System.hh"
 #include "mem/tport.hh"
 #include "params/RubyPort.hh"
 
@@ -54,6 +55,7 @@ class RubyPort : public MemObject
         M5Port(const std::string &_name, RubyPort *_port);
         bool sendTiming(PacketPtr pkt);
         void hitCallback(PacketPtr pkt);
+        unsigned deviceBlockSize() const;
 
       protected:
         virtual bool recvTiming(PacketPtr pkt);