diff --git a/ports-foc/lib/mk/l4lx.mk b/ports-foc/lib/mk/l4lx.mk
index 250320048b..ea9a52f0e8 100644
--- a/ports-foc/lib/mk/l4lx.mk
+++ b/ports-foc/lib/mk/l4lx.mk
@@ -26,6 +26,7 @@ SRC_CC  += env.cc \
            l4lx_memory.cc \
            l4lx_task.cc \
            l4lx_thread.cc \
+           l4x_pagefault.cc \
            rm.cc \
            startup.cc
 
diff --git a/ports-foc/src/lib/l4lx/dataspace.cc b/ports-foc/src/lib/l4lx/dataspace.cc
index efe22f7d86..9064ecda05 100644
--- a/ports-foc/src/lib/l4lx/dataspace.cc
+++ b/ports-foc/src/lib/l4lx/dataspace.cc
@@ -24,7 +24,8 @@ L4lx::Dataspace* L4lx::Dataspace_tree::insert(const char* name,
 	using namespace L4lx;
 
 	Genode::Dataspace_client dsc(cap);
-	Dataspace *ds = new (Genode::env()->heap()) Dataspace(name, dsc.size(), cap);
+	Dataspace *ds =
+		new (Genode::env()->heap()) Single_dataspace(name, dsc.size(), cap);
 	insert(ds);
 	return ds;
 }
diff --git a/ports-foc/src/lib/l4lx/include/dataspace.h b/ports-foc/src/lib/l4lx/include/dataspace.h
index c95e3f402d..b3708f67d3 100644
--- a/ports-foc/src/lib/l4lx/include/dataspace.h
+++ b/ports-foc/src/lib/l4lx/include/dataspace.h
@@ -17,7 +17,9 @@
 /* Genode includes */
 #include <dataspace/client.h>
 #include <base/cap_map.h>
+#include <base/env.h>
 #include <util/avl_tree.h>
+#include <rm_session/connection.h>
 
 namespace Fiasco {
 #include <l4/sys/types.h>
@@ -29,10 +31,9 @@ namespace L4lx {
 	{
 		private:
 
-			const char*                  _name;
-			Genode::size_t               _size;
-			Genode::Dataspace_capability _cap;
-			Fiasco::l4_cap_idx_t         _ref;
+			const char*          _name;
+			Genode::size_t       _size;
+			Fiasco::l4_cap_idx_t _ref;
 
 		public:
 
@@ -40,17 +41,10 @@ namespace L4lx {
 			 ** Constructors **
 			 ******************/
 
-			Dataspace(const char*                    name,
-			          Genode::size_t                 size,
-			          Genode::Dataspace_capability   ds,
-			          Fiasco::l4_cap_idx_t           ref)
-			: _name(name), _size(size), _cap(ds), _ref(ref) {}
-
-			Dataspace(const char*                    name,
-			          Genode::size_t                 size,
-			          Genode::Dataspace_capability   ds)
-			: _name(name), _size(size), _cap(ds),
-				_ref(Genode::cap_idx_alloc()->alloc_range(1)->kcap()) {}
+			Dataspace(const char*          name,
+			          Genode::size_t       size,
+			          Fiasco::l4_cap_idx_t ref)
+			: _name(name), _size(size), _ref(ref) {}
 
 
 			/***************
@@ -59,9 +53,10 @@ namespace L4lx {
 
 			const char*                  name() const { return _name; }
 			Genode::size_t               size()       { return _size; }
-			Genode::Dataspace_capability cap()        { return _cap;  }
 			Fiasco::l4_cap_idx_t         ref()        { return _ref;  }
 
+			virtual Genode::Dataspace_capability cap() = 0;
+			virtual bool map(Genode::size_t offset)    = 0;
 
 			/************************
 			 ** Avl_node interface **
@@ -79,6 +74,100 @@ namespace L4lx {
 	};
 
 
+	class Single_dataspace : public Dataspace
+	{
+		private:
+
+			Genode::Dataspace_capability _cap;
+
+		public:
+
+			Single_dataspace(const char*                    name,
+							 Genode::size_t                 size,
+							 Genode::Dataspace_capability   ds,
+			                 Fiasco::l4_cap_idx_t           ref =
+				Genode::cap_idx_alloc()->alloc_range(1)->kcap())
+			: Dataspace(name, size, ref), _cap(ds) {}
+
+			Genode::Dataspace_capability cap() { return _cap; }
+			bool map(Genode::size_t offset)    { return true; }
+	};
+
+
+	class Chunked_dataspace : public Dataspace
+	{
+		private:
+
+			class Chunk : public Genode::Avl_node<Chunk>
+			{
+				private:
+
+					Genode::size_t               _offset;
+					Genode::size_t               _size;
+					Genode::Dataspace_capability _cap;
+
+				public:
+
+					Chunk(Genode::size_t off, Genode::size_t size,
+					      Genode::Dataspace_capability cap)
+					: _offset(off), _size(size), _cap(cap) {}
+
+					Genode::size_t               offset() { return _offset; }
+					Genode::size_t               size()   { return _size;   }
+					Genode::Dataspace_capability cap()    { return _cap;    }
+
+					bool higher(Chunk *n) { return n->_offset > _offset; }
+
+					Chunk *find_by_offset(Genode::size_t off)
+					{
+						if (off >= _offset && off < _offset+_size) return this;
+
+						Chunk *n = Genode::Avl_node<Chunk>::child(off > _offset);
+						return n ? n->find_by_offset(off) : 0;
+					}
+			};
+
+			Genode::Rm_connection   _rm;
+			Genode::Avl_tree<Chunk> _chunks;
+			Genode::size_t          _chunk_size;
+			Genode::size_t          _chunk_size_log2;
+
+	public:
+
+			Chunked_dataspace(const char*          name,
+							  Genode::size_t       size,
+							  Fiasco::l4_cap_idx_t ref,
+			                  Genode::size_t       chunk_size)
+			: Dataspace(name, size, ref), _rm(0, size), _chunk_size(chunk_size),
+			  _chunk_size_log2(Genode::log2(_chunk_size)) {}
+
+			Genode::Dataspace_capability cap() { return _rm.dataspace(); }
+
+			bool map(Genode::size_t off)
+			{
+				off = Genode::align_addr((off-(_chunk_size-1)), _chunk_size_log2);
+
+				Chunk* c = _chunks.first() ? _chunks.first()->find_by_offset(off) : 0;
+				if (c) return true;
+
+				try {
+					Genode::Dataspace_capability cap =
+						Genode::env()->ram_session()->alloc(_chunk_size);
+					_chunks.insert(new (Genode::env()->heap())
+								   Chunk(off, _chunk_size, cap));
+					_rm.attach(cap, 0, 0, true, off);
+					return true;
+				} catch(Genode::Ram_session::Quota_exceeded) {
+					PWRN("Could not allocate new dataspace chunk");
+				} catch(Genode::Rm_session::Attach_failed) {
+					PWRN("Attach of chunk dataspace of size %zx to %p failed",
+					     _chunk_size, (void*) off);
+				}
+				return false;
+			}
+	};
+
+
 	class Dataspace_tree : public Genode::Avl_tree<Dataspace>
 	{
 		public:
diff --git a/ports-foc/src/lib/l4lx/l4_re_c_mem_alloc.cc b/ports-foc/src/lib/l4lx/l4_re_c_mem_alloc.cc
index 01aa3db4d2..69487b2222 100644
--- a/ports-foc/src/lib/l4lx/l4_re_c_mem_alloc.cc
+++ b/ports-foc/src/lib/l4lx/l4_re_c_mem_alloc.cc
@@ -57,34 +57,16 @@ extern "C" {
 		if (DEBUG)
 			PDBG("size=%lx mem=%lx flags=%lx", size, mem, flags);
 
-		Genode::Dataspace_capability cap;
-
+		Dataspace *ds;
 		if (size > chunk_size) {
-			Genode::Rm_connection *rmc = new (Genode::env()->heap())
-			                                 Genode::Rm_connection(0, size);
-
-			const unsigned long num_chunks = size / chunk_size;
-			const unsigned long remainder  = size % chunk_size;
-
-			for (unsigned long i = 0; i < num_chunks; i++) {
-				Genode::Dataspace_capability cap =
-					Genode::env()->ram_session()->alloc(chunk_size);
-				rmc->attach(cap);
-			}
-
-			if (remainder > 0) {
-				Genode::Dataspace_capability cap =
-					Genode::env()->ram_session()->alloc(remainder);
-				rmc->attach(cap);
-			}
-
-			cap = rmc->dataspace();
+			ds = new (Genode::env()->heap())
+				Chunked_dataspace("lx_memory", size, mem, chunk_size);
 		} else {
-			cap = Genode::env()->ram_session()->alloc(size);
+			Genode::Dataspace_capability cap =
+				Genode::env()->ram_session()->alloc(size);
+			ds = new (Genode::env()->heap())
+				Single_dataspace("lx_memory", size, cap, mem);
 		}
-
-		Dataspace *ds = new (Genode::env()->heap())
-			Dataspace("lx_memory", size, cap, mem);
 		Env::env()->dataspaces()->insert(ds);
 		return 0;
 	}
diff --git a/ports-foc/src/lib/l4lx/l4_re_env.cc b/ports-foc/src/lib/l4lx/l4_re_env.cc
index 1abdde9e51..85362fe016 100644
--- a/ports-foc/src/lib/l4lx/l4_re_env.cc
+++ b/ports-foc/src/lib/l4lx/l4_re_env.cc
@@ -57,7 +57,7 @@ extern "C" {
 			l4re_env_cap_entry_t *entry = new (Genode::env()->heap())
 				l4re_env_cap_entry_t();
 			Dataspace *ds = new (Genode::env()->heap())
-				Dataspace("initrd", size, cap);
+				Single_dataspace("initrd", size, cap);
 			Env::env()->dataspaces()->insert(ds);
 			entry->cap = ds->ref();
 			return entry;
diff --git a/ports-foc/src/lib/l4lx/l4x_pagefault.cc b/ports-foc/src/lib/l4lx/l4x_pagefault.cc
new file mode 100644
index 0000000000..260399f912
--- /dev/null
+++ b/ports-foc/src/lib/l4lx/l4x_pagefault.cc
@@ -0,0 +1,28 @@
+#include <env.h>
+#include <rm.h>
+
+namespace Fiasco {
+#include <l4/util/util.h>
+#include <l4/sys/linkage.h>
+}
+
+extern "C" L4_CV int l4x_forward_pf(Fiasco::l4_umword_t addr,
+                              Fiasco::l4_umword_t pc, int extra_write)
+{
+	using namespace Fiasco;
+
+	Genode::size_t size          = L4_PAGESIZE;
+	Genode::addr_t ds_start_addr = addr;
+	L4lx::Region *r = L4lx::Env::env()->rm()->find_region(&ds_start_addr, &size);
+	L4lx::Dataspace *ds = r ? r->ds() : 0;
+	if (ds && !ds->map(addr - r->addr()))
+		return 0;
+
+	if (!extra_write)
+		l4_touch_ro((void*)l4_trunc_page(addr), L4_LOG2_PAGESIZE);
+	else
+		l4_touch_rw((void*)l4_trunc_page(addr), L4_LOG2_PAGESIZE);
+	return 1;
+}
+
+
diff --git a/ports-foc/src/lib/l4lx/rm.cc b/ports-foc/src/lib/l4lx/rm.cc
index 4165c284fe..2a21c4a537 100644
--- a/ports-foc/src/lib/l4lx/rm.cc
+++ b/ports-foc/src/lib/l4lx/rm.cc
@@ -159,8 +159,9 @@ Region* Region_manager::reserve_range(Genode::size_t size, int align,
 void Region_manager::reserve_range(Genode::addr_t addr, Genode::size_t size,
                                    const char *name)
 {
+	Genode::Dataspace_capability cap;
 	L4lx::Dataspace *ds = new (Genode::env()->heap())
-		L4lx::Dataspace(name, size, Genode::reinterpret_cap_cast<Genode::Dataspace>(Genode::Native_capability()));
+		L4lx::Single_dataspace(name, size, cap);
 	L4lx::Env::env()->dataspaces()->insert(ds);
 	alloc_addr(size, (Genode::addr_t)addr);
 	metadata((void*)addr, Region(addr, size, ds));