diff --git a/src/lib_scoru_wasm/test/ast_generators.ml b/src/lib_scoru_wasm/test/ast_generators.ml
index 767a53e3f87683a27c3d7396a05b61bd35996b32..03e04c4e9cbea73640ab226c8719cb2e58a226bb 100644
--- a/src/lib_scoru_wasm/test/ast_generators.ml
+++ b/src/lib_scoru_wasm/test/ast_generators.ml
@@ -787,13 +787,16 @@ let step_kont_gen ~module_reg =
       sk_trapped_gen;
     ]
 
-let config_gen ~host_funcs ~module_reg =
+let buffers_gen =
   let* input = input_buffer_gen in
   let _input_list =
     Lwt_main.run @@ Lazy_vector.ZVector.to_list
     @@ Lazy_vector.Mutable.ZVector.snapshot input.content
   in
-  let* output = output_buffer_gen in
+  let+ output = output_buffer_gen in
+  Eval.{input; output}
+
+let config_gen ~host_funcs ~module_reg =
   let* stack_size_limit = small_int in
   let+ step_kont = step_kont_gen ~module_reg in
-  Eval.{input; output; step_kont; host_funcs; stack_size_limit}
+  Eval.{step_kont; host_funcs; stack_size_limit}
diff --git a/src/lib_scoru_wasm/test/ast_printer.ml b/src/lib_scoru_wasm/test/ast_printer.ml
index ea70d7aac27664d8f9e7704ab09c4be0215c4089..688d857089b3b30264ba699b431508f2efce16b7 100644
--- a/src/lib_scoru_wasm/test/ast_printer.ml
+++ b/src/lib_scoru_wasm/test/ast_printer.ml
@@ -544,15 +544,19 @@ let pp_output_buffer out (output : Output_buffer.t) =
     (pp_vector (fun o -> pp_index_vector o))
     (Output_buffer.Level_Vector.snapshot output)
 
-let pp_config out
-    Eval.{input; output; step_kont; host_funcs = _; stack_size_limit} =
+let pp_buffers out Eval.{input; output} =
   Format.fprintf
     out
-    "@[<v 2>{input = %a;@;output = %a;@;frame_kont = %a;@;budget = %i;@;}@]"
+    "@[<v 2>{input = %a;@;output = %a;@;}@]"
     pp_input_buffer
     input
     pp_output_buffer
     output
+
+let pp_config out Eval.{step_kont; host_funcs = _; stack_size_limit} =
+  Format.fprintf
+    out
+    "@[<v 2>{frame_kont = %a;@;budget = %i;@;}@]"
     pp_step_kont
     step_kont
     stack_size_limit
diff --git a/src/lib_scoru_wasm/test/test_get_set.ml b/src/lib_scoru_wasm/test/test_get_set.ml
index 98a5b0515612741280b565e69bb5058a635a62f8..3329fa9a9fb11413101b0a345a3c241098d535a2 100644
--- a/src/lib_scoru_wasm/test/test_get_set.ml
+++ b/src/lib_scoru_wasm/test/test_get_set.ml
@@ -87,6 +87,10 @@ let floppy_encoding =
 
 let inp_encoding = Tree_encoding.value ["input"; "0"; "1"] Data_encoding.string
 
+(* Replicates the encoding of buffers from [Wasm_pvm] as part of the pvm_state. *)
+let buffers_encoding =
+  Tree_encoding.scope ["pvm"; "buffers"] Wasm_encoding.buffers_encoding
+
 let zero =
   WithExceptions.Option.get
     ~loc:__LOC__
@@ -124,7 +128,10 @@ let initialise_tree () =
       Wasm_pvm_sig.Input_required
       tree
   in
-  Lwt.return tree
+  Tree_encoding_runner.encode
+    buffers_encoding
+    (Tezos_webassembly_interpreter.Eval.buffers ())
+    tree
 
 let make_inbox_info ~inbox_level ~message_counter =
   Wasm_pvm_sig.
@@ -225,8 +232,6 @@ let test_set_input () =
   let tick_state =
     Eval.
       {
-        input = Input_buffer.alloc ();
-        output = Output_buffer.alloc ();
         host_funcs;
         step_kont = SK_Result (Vector.empty ());
         stack_size_limit = 1000;
@@ -274,17 +279,8 @@ let test_get_output () =
   let output = Output_buffer.alloc () in
   Output_buffer.set_level output 0l ;
   let* () = Output_buffer.set_value output @@ Bytes.of_string "hello" in
-  let tick_state =
-    Eval.
-      {
-        input = Input_buffer.alloc ();
-        output;
-        host_funcs;
-        step_kont = SK_Result (Vector.empty ());
-        stack_size_limit = 1000;
-      }
-  in
-  let* tree = encode_tick_state ~host_funcs tick_state tree in
+  let buffers = Eval.{input = Input_buffer.alloc (); output} in
+  let* tree = Tree_encoding_runner.encode buffers_encoding buffers tree in
   let output_info = make_output_info ~outbox_level:0 ~message_index:0 in
   let* payload = Wasm.get_output output_info tree in
   assert (payload = "hello") ;
diff --git a/src/lib_scoru_wasm/test/test_wasm_encoding.ml b/src/lib_scoru_wasm/test/test_wasm_encoding.ml
index 07f090e28d1156d2850a793fe2189d0834e43a3b..0c3e797f148adbc8f89d9ee7fe1f81a6820160c7 100644
--- a/src/lib_scoru_wasm/test/test_wasm_encoding.ml
+++ b/src/lib_scoru_wasm/test/test_wasm_encoding.ml
@@ -121,19 +121,12 @@ let test_frame_tree =
     ~gen:(fun ~host_funcs:_ -> Ast_generators.frame_gen)
     ~encoding:(fun ~host_funcs:_ -> Wasm_encoding.frame_encoding)
 
-(** Test serialize/deserialize input buffers and compare trees. *)
-let test_input_buffer_tree =
+(** Test serialize/deserialize input and output buffers and compare trees. *)
+let test_buffers_tree =
   test_generic_tree
-    ~pp:Ast_printer.pp_input_buffer
-    ~gen:(fun ~host_funcs:_ ~module_reg:_ -> Ast_generators.input_buffer_gen)
-    ~encoding:(fun ~host_funcs:_ -> Wasm_encoding.input_buffer_encoding)
-
-(** Test serialize/deserialize output buffers and compare trees. *)
-let test_output_buffer_tree =
-  test_generic_tree
-    ~pp:Ast_printer.pp_output_buffer
-    ~gen:(fun ~host_funcs:_ ~module_reg:_ -> Ast_generators.output_buffer_gen)
-    ~encoding:(fun ~host_funcs:_ -> Wasm_encoding.output_buffer_encoding)
+    ~pp:Ast_printer.pp_buffers
+    ~gen:(fun ~host_funcs:_ ~module_reg:_ -> Ast_generators.buffers_gen)
+    ~encoding:(fun ~host_funcs:_ -> Wasm_encoding.buffers_encoding)
 
 (** Test serialize/deserialize values and compare trees. *)
 let test_values_tree =
@@ -167,8 +160,7 @@ let tests =
     tztest "Module trees" `Quick test_module_tree;
     tztest "Values trees" `Quick test_values_tree;
     tztest "Admin_instr trees" `Quick test_admin_instr_tree;
-    tztest "Input_buffer trees" `Quick test_input_buffer_tree;
-    tztest "Output_buffer trees" `Quick test_output_buffer_tree;
+    tztest "Input and output buffers trees" `Quick test_buffers_tree;
     tztest "Frame trees" `Quick test_frame_tree;
     tztest "Config trees" `Quick test_config_tree;
   ]
diff --git a/src/lib_scoru_wasm/wasm_encoding.ml b/src/lib_scoru_wasm/wasm_encoding.ml
index 5325c5197f1a63058499f6770d5af6b363dd9643..96ccefa95fdf712d9c5d2bbf539ec64c25f63224 100644
--- a/src/lib_scoru_wasm/wasm_encoding.ml
+++ b/src/lib_scoru_wasm/wasm_encoding.ml
@@ -1114,13 +1114,19 @@ let output_buffer_encoding =
 
 let config_encoding ~host_funcs =
   conv
-    (fun (input, output, step_kont, stack_size_limit) ->
-      Eval.{input; output; step_kont; host_funcs; stack_size_limit})
-    (fun Eval.{input; output; step_kont; stack_size_limit; _} ->
-      (input, output, step_kont, stack_size_limit))
-    (tup4
+    (fun (step_kont, stack_size_limit) ->
+      Eval.{step_kont; host_funcs; stack_size_limit})
+    (fun Eval.{step_kont; stack_size_limit; _} -> (step_kont, stack_size_limit))
+    (tup2
        ~flatten:true
-       (scope ["input"] input_buffer_encoding)
-       (scope ["output"] output_buffer_encoding)
        (scope ["step_kont"] step_kont_encoding)
        (value ["stack_size_limit"] Data_encoding.int31))
+
+let buffers_encoding =
+  conv
+    (fun (input, output) -> Eval.{input; output})
+    (fun Eval.{input; output; _} -> (input, output))
+    (tup2
+       ~flatten:true
+       (scope ["input"] input_buffer_encoding)
+       (scope ["output"] output_buffer_encoding))
diff --git a/src/lib_scoru_wasm/wasm_encoding.mli b/src/lib_scoru_wasm/wasm_encoding.mli
index f4290c8438a78fcb543d6ff3e4fdb4f3c2f1afca..49d0fa6ba129f4a23ff548111fd2d6b1d82b8b79 100644
--- a/src/lib_scoru_wasm/wasm_encoding.mli
+++ b/src/lib_scoru_wasm/wasm_encoding.mli
@@ -98,3 +98,5 @@ val frame_encoding : Eval.frame Tree_encoding.t
 
 val config_encoding :
   host_funcs:Host_funcs.registry -> Eval.config Tree_encoding.t
+
+val buffers_encoding : Eval.buffers Tree_encoding.t
diff --git a/src/lib_scoru_wasm/wasm_pvm.ml b/src/lib_scoru_wasm/wasm_pvm.ml
index fa283b84c755a2489e04671cbf573fe55d155956..30b0a5cabc88f22cdfb0d6f98bfd1a87f51d9c29 100644
--- a/src/lib_scoru_wasm/wasm_pvm.ml
+++ b/src/lib_scoru_wasm/wasm_pvm.ml
@@ -50,6 +50,8 @@ type pvm_state = {
   durable : Durable.t;  (** The durable storage of the PVM. *)
   module_reg : Wasm.Instance.module_reg;
       (** Module registry of the loaded kernel. *)
+  buffers : Wasm.Eval.buffers;
+      (** Input and outut buffers used by the PVM host functions. *)
   tick_state : tick_state;  (** The current tick state. *)
   input_request : Wasm_pvm_sig.input_request;
       (** Signals whether or not the PVM needs input. *)
@@ -123,6 +125,9 @@ struct
           | Wasm_pvm_sig.No_input_required -> false)
         (Tree_encoding.value ~default:false [] Data_encoding.bool)
 
+    let durable_buffers_encoding =
+      Tree_encoding.(scope ["pvm"; "buffers"] Wasm_encoding.buffers_encoding)
+
     let pvm_state_encoding =
       let open Tree_encoding in
       conv
@@ -130,6 +135,7 @@ struct
                current_tick,
                durable,
                module_reg,
+               buffers,
                tick_state,
                input_request ) ->
           {
@@ -137,6 +143,12 @@ struct
             current_tick;
             durable;
             module_reg;
+            buffers =
+              (*`Gather_floppies` uses `get_info`, that decodes the state of the
+                PVM, which at the start of the rollup doesn't exist. *)
+              Option.value_f
+                ~default:Tezos_webassembly_interpreter.Eval.buffers
+                buffers;
             tick_state;
             input_request;
           })
@@ -145,6 +157,7 @@ struct
                current_tick;
                durable;
                module_reg;
+               buffers;
                tick_state;
                input_request;
              } ->
@@ -152,20 +165,22 @@ struct
             current_tick,
             durable,
             module_reg,
+            Some buffers,
             tick_state,
             input_request ))
-        (tup6
+        (tup7
            ~flatten:true
            (value_option ["wasm"; "input"] Wasm_pvm_sig.input_info_encoding)
            (value ~default:Z.zero ["wasm"; "current_tick"] Data_encoding.n)
            (scope ["durable"] Durable.encoding)
            (scope ["modules"] Wasm_encoding.module_instances_encoding)
+           (option durable_buffers_encoding)
            (scope ["wasm"] tick_state_encoding)
            (scope ["input"; "consuming"] input_request_encoding))
 
     let kernel_key = Durable.key_of_string_exn "/kernel/boot.wasm"
 
-    let unsafe_next_tick_state {module_reg; durable; tick_state; _} =
+    let unsafe_next_tick_state {module_reg; buffers; durable; tick_state; _} =
       let open Lwt_syntax in
       match tick_state with
       | Decode {module_kont = MKStop ast_module; _} ->
@@ -243,6 +258,7 @@ struct
               ~check_module_exports:Exports_memory_0
               ~module_reg
               ~self
+              buffers
               host_funcs
               ast_module
               externs
@@ -252,7 +268,7 @@ struct
       | Eval eval_config ->
           let store = Durable.to_storage durable in
           let+ store', eval_config =
-            Wasm.Eval.step ~durable:store module_reg eval_config
+            Wasm.Eval.step ~durable:store module_reg eval_config buffers
           in
           let durable' = Durable.of_storage ~default:durable store' in
           (durable', Eval eval_config)
@@ -355,20 +371,15 @@ struct
 
     let compute_step tree = compute_step_many ~max_steps:1L tree
 
-    let out_encoding =
-      Tree_encoding.scope
-        ["wasm"; "value"; "output"]
-        Wasm_encoding.output_buffer_encoding
-
     let get_output output_info tree =
       let open Lwt_syntax in
       let open Wasm_pvm_sig in
       let {outbox_level; message_index} = output_info in
       let outbox_level = Bounded.Non_negative_int32.to_value outbox_level in
-      let* output_buffer = Tree_encoding_runner.decode out_encoding tree in
-      let+ payload =
-        Wasm.Output_buffer.get output_buffer outbox_level message_index
+      let* {output; _} =
+        Tree_encoding_runner.decode durable_buffers_encoding tree
       in
+      let+ payload = Wasm.Output_buffer.get output outbox_level message_index in
       Bytes.to_string payload
 
     let get_info tree =
@@ -390,11 +401,11 @@ struct
       let* pvm_state = Tree_encoding_runner.decode pvm_state_encoding tree in
       let* tick_state =
         match pvm_state.tick_state with
-        | Eval {input; _} ->
+        | Eval _ ->
             let+ () =
               Wasm.Input_buffer.(
                 enqueue
-                  input
+                  pvm_state.buffers.input
                   {
                     (* This is to distinguish (0) Inbox inputs from (1)
                        DAL/Slot_header inputs. *)
diff --git a/src/lib_webassembly/bin/script/run.ml b/src/lib_webassembly/bin/script/run.ml
index e08e26fee9a1a0a2dc5e539506f064c04894a9f5..bd5b9708cb314fa45ea7ade911074fcee15a3bc2 100644
--- a/src/lib_webassembly/bin/script/run.ml
+++ b/src/lib_webassembly/bin/script/run.ml
@@ -325,7 +325,8 @@ let instantiate_module x_opt m imports =
         Instance.Module_key (Printf.sprintf "__unnamed_%i" index)
     | Some name -> Instance.Module_key name.it
   in
-  Eval.init ~module_reg:instances ~self host_funcs_registry m imports
+  let buffers = Eval.buffers () in
+  Eval.init ~module_reg:instances ~self buffers host_funcs_registry m imports
 
 let bind_lazy module_reg name instance =
   Option.iter
diff --git a/src/lib_webassembly/exec/eval.ml b/src/lib_webassembly/exec/eval.ml
index a412cb0c0a9b2ddc7c2615173c4a9c2f281b1bfc..9419dff1b73b0c0f539478a07ab3d38639d7dc7b 100644
--- a/src/lib_webassembly/exec/eval.ml
+++ b/src/lib_webassembly/exec/eval.ml
@@ -226,9 +226,9 @@ type step_kont =
   | SK_Result of value Vector.t
   | SK_Trapped of string phrase
 
+type buffers = {input : input_inst; output : output_inst}
+
 type config = {
-  input : input_inst;
-  output : output_inst;
   step_kont : step_kont;
   host_funcs : Host_funcs.registry;
   stack_size_limit : int;
@@ -236,8 +236,11 @@ type config = {
 
 let frame inst locals = {inst; locals}
 
-let config ?(input = Input_buffer.alloc ()) ?(output = Output_buffer.alloc ())
-    host_funcs ?frame_arity inst vs es =
+let buffers ?(input = Input_buffer.alloc ()) ?(output = Output_buffer.alloc ())
+    () =
+  {input; output}
+
+let config host_funcs ?frame_arity inst vs es =
   let frame = frame inst (Vector.empty ()) in
   let label_kont =
     label_kont
@@ -252,8 +255,6 @@ let config ?(input = Input_buffer.alloc ()) ?(output = Output_buffer.alloc ())
     {frame_arity; frame_specs = frame; frame_label_kont = label_kont}
   in
   {
-    input;
-    output;
     step_kont = SK_Start (frame_stack, Vector.empty ());
     host_funcs;
     stack_size_limit = 300;
@@ -321,7 +322,7 @@ let block_type inst bt =
 let vmtake n vs = match n with Some n -> Vector.split vs n |> fst | None -> vs
 
 let invoke_step ?(durable = Durable_storage.empty) (module_reg : module_reg) c
-    frame at = function
+    buffers frame at = function
   | Inv_stop _ -> assert false
   | Inv_start {func; code = vs, es} -> (
       let (FuncType (ins, out)) = func_type_of func in
@@ -352,7 +353,12 @@ let invoke_step ?(durable = Durable_storage.empty) (module_reg : module_reg) c
               let* inst = resolve_module_ref module_reg frame.inst in
               let* args = Vector.to_list args in
               let+ durable, res =
-                f c.input c.output durable inst.memories (List.rev args)
+                f
+                  buffers.input
+                  buffers.output
+                  durable
+                  inst.memories
+                  (List.rev args)
               in
               let vs' = Vector.prepend_list res vs' in
               (durable, Inv_stop {code = (vs', es); fresh_frame = None}))
@@ -1235,10 +1241,11 @@ let label_step :
     Durable_storage.t ->
     module_reg ->
     config ->
+    buffers ->
     frame ->
     label_step_kont ->
     (Durable_storage.t * label_step_kont) Lwt.t =
- fun durable module_reg c frame label_kont ->
+ fun durable module_reg c buffers frame label_kont ->
   match label_kont with
   | LS_Push_frame _ | LS_Modify_top _ -> assert false
   | LS_Start (Label_stack (label, stack)) ->
@@ -1345,11 +1352,11 @@ let label_step :
           | None -> LS_Modify_top label_kont )
   | LS_Craft_frame (label, istep) ->
       let+ durable, istep =
-        invoke_step ~durable module_reg c frame no_region istep
+        invoke_step ~durable module_reg c buffers frame no_region istep
       in
       (durable, LS_Craft_frame (label, istep))
 
-let frame_step durable module_reg c = function
+let frame_step durable module_reg c buffers = function
   | SK_Result _ | SK_Trapped _ -> assert false
   | SK_Start (frame, stack) ->
       let+ kont =
@@ -1394,18 +1401,18 @@ let frame_step durable module_reg c = function
       Lwt.return (durable, SK_Start (frame', Vector.cons frame stack))
   | SK_Next (frame, stack, istep) ->
       let+ durable, istep =
-        label_step durable module_reg c frame.frame_specs istep
+        label_step durable module_reg c buffers frame.frame_specs istep
       in
       (durable, SK_Next (frame, stack, istep))
 
-let step ?(durable = Durable_storage.empty) module_reg c =
+let step ?(durable = Durable_storage.empty) module_reg c buffers =
   match c.step_kont with
   | SK_Result _ | SK_Trapped _ -> assert false
   | kont ->
-      let+ durable, step_kont = frame_step durable module_reg c kont in
+      let+ durable, step_kont = frame_step durable module_reg c buffers kont in
       (durable, {c with step_kont})
 
-let rec eval durable module_reg (c : config) :
+let rec eval durable module_reg (c : config) buffers :
     (Durable_storage.t * value list) Lwt.t =
   match c.step_kont with
   | SK_Result vs ->
@@ -1413,8 +1420,8 @@ let rec eval durable module_reg (c : config) :
       (durable, values)
   | SK_Trapped {it = msg; at} -> Trap.error at msg
   | _ ->
-      let* durable, c = step ~durable module_reg c in
-      eval durable module_reg c
+      let* durable, c = step ~durable module_reg c buffers in
+      eval durable module_reg c buffers
 
 (* Functions & Constants *)
 
@@ -1440,17 +1447,16 @@ let invoke ~module_reg ~caller ?(input = Input_buffer.alloc ())
   let n = Vector.num_elements out in
   let c =
     config
-      ~input
-      ~output
       host_funcs
       ~frame_arity:n
       inst
       (Vector.of_list (List.rev vs))
       (Vector.singleton (Invoke func @@ at))
   in
+  let buffers = buffers ~input ~output () in
   Lwt.catch
     (fun () ->
-      let+ durable, values = eval durable module_reg c in
+      let+ durable, values = eval durable module_reg c buffers in
       (durable, List.rev values))
     (function
       | Stack_overflow -> Exhaustion.error at "call stack exhausted"
@@ -1470,14 +1476,14 @@ let eval_const_kont inst (const : const) =
 
 let eval_const_completed = function EC_Stop v -> Some v | _ -> None
 
-let eval_const_step module_reg = function
+let eval_const_step module_reg buffers = function
   | EC_Next {step_kont = SK_Result vs; _} ->
       if Vector.num_elements vs = 1l then
         let+ v, _ = Vector.pop vs in
         EC_Stop v
       else Crash.error Source.no_region "wrong number of results on stack"
   | EC_Next c ->
-      let+ _, c = step module_reg c in
+      let+ _, c = step module_reg c buffers in
       EC_Next c
   | EC_Stop _ -> assert false
 
@@ -1508,11 +1514,11 @@ let create_global_completed (gtype, kont) =
   | Some v -> Some (Global.alloc gtype v)
   | None -> None
 
-let create_global_step module_reg ((gtype, ekont) as kont) =
+let create_global_step module_reg buffers ((gtype, ekont) as kont) =
   match create_global_completed kont with
   | Some _ -> assert false
   | None ->
-      let+ ekont = eval_const_step module_reg ekont in
+      let+ ekont = eval_const_step module_reg buffers ekont in
       (gtype, ekont)
 
 let create_export (inst : module_inst) (ex : export) : export_inst Lwt.t =
@@ -1763,7 +1769,7 @@ let create_elem_completed : create_elem_kont -> elem_inst option =
  fun kont ->
   if tick_map_completed kont then Some (ref kont.map.destination) else None
 
-let create_elem_step ~module_reg inst :
+let create_elem_step ~module_reg buffers inst :
     create_elem_kont -> create_elem_kont Lwt.t =
  fun tick ->
   tick_map_step
@@ -1772,7 +1778,7 @@ let create_elem_step ~module_reg inst :
       match eval_const_completed x with
       | Some x -> Some (as_ref x)
       | None -> None)
-    (eval_const_step module_reg)
+    (eval_const_step module_reg buffers)
     tick
 
 type exports_acc = {exports : extern NameMap.t; exports_memory_0 : bool}
@@ -1839,10 +1845,11 @@ let section_inner_step :
     type kont a b.
     module_inst ModuleMap.t ->
     module_key ->
+    buffers ->
     (kont, a, b) init_section ->
     kont ->
     kont Lwt.t =
- fun module_reg self ->
+ fun module_reg self buffers ->
   let lift_either f =
     let open Either in
     function
@@ -1853,7 +1860,7 @@ let section_inner_step :
   in
   function
   | Func -> lift_either (create_func module_reg self)
-  | Global -> create_global_step module_reg
+  | Global -> create_global_step module_reg buffers
   | Table -> lift_either (fun x -> Lwt.return (create_table x))
   | Memory -> lift_either (fun x -> Lwt.return (create_memory x))
 
@@ -1877,7 +1884,7 @@ type memory_export_rules = Exports_memory_0 | No_memory_export_rules
 exception Missing_memory_0_export
 
 let init_step ?(check_module_exports = No_memory_export_rules) ~module_reg ~self
-    host_funcs (m : module_) (exts : extern Vector.t) = function
+    buffers host_funcs (m : module_) (exts : extern Vector.t) = function
   | IK_Start ->
       (* Initialize as empty module. *)
       update_module_ref module_reg self empty_module_inst ;
@@ -1916,7 +1923,7 @@ let init_step ?(check_module_exports = No_memory_export_rules) ~module_reg ~self
         tick_map_step
           (section_inner_kont self sec)
           (section_inner_completed sec)
-          (section_inner_step module_reg self sec)
+          (section_inner_step module_reg self buffers sec)
           tick
       in
       IK_Aggregate (inst0, sec, tick)
@@ -1955,7 +1962,7 @@ let init_step ?(check_module_exports = No_memory_export_rules) ~module_reg ~self
         tick_map_step
           create_elem_kont
           create_elem_completed
-          (create_elem_step ~module_reg self)
+          (create_elem_step ~module_reg buffers self)
           tick
       in
       IK_Elems (inst0, tick)
@@ -2013,18 +2020,25 @@ let init_step ?(check_module_exports = No_memory_export_rules) ~module_reg ~self
       Lwt.return (IK_Stop inst)
   | IK_Eval (_, {step_kont = SK_Trapped {it = msg; at}; _}) -> Trap.error at msg
   | IK_Eval (inst, config) ->
-      let+ _, config = step module_reg config in
+      let+ _, config = step module_reg config buffers in
       IK_Eval (inst, config)
   | IK_Stop _ -> raise (Init_step_error Init_step)
 
-let init ~module_reg ~self host_funcs (m : module_) (exts : extern list) :
-    module_inst Lwt.t =
+let init ~module_reg ~self buffers host_funcs (m : module_) (exts : extern list)
+    : module_inst Lwt.t =
   let open Lwt.Syntax in
   let rec go = function
     | IK_Stop inst -> Lwt.return inst
     | kont ->
         let* kont =
-          init_step ~module_reg ~self host_funcs m (Vector.of_list exts) kont
+          init_step
+            ~module_reg
+            ~self
+            buffers
+            host_funcs
+            m
+            (Vector.of_list exts)
+            kont
         in
         go kont
   in
diff --git a/src/lib_webassembly/exec/eval.mli b/src/lib_webassembly/exec/eval.mli
index 0f8888dd4c8cb3034a396a0037c942ef4dab4f16..473c9ffde0c368f8a6aebf31d999c40f96ec1a0f 100644
--- a/src/lib_webassembly/exec/eval.mli
+++ b/src/lib_webassembly/exec/eval.mli
@@ -126,9 +126,9 @@ type step_kont =
   | SK_Result of value Vector.t
   | SK_Trapped of string Source.phrase
 
+type buffers = {input : input_inst; output : output_inst}
+
 type config = {
-  input : input_inst;
-  output : output_inst;
   step_kont : step_kont;
   host_funcs : Host_funcs.registry;
   stack_size_limit : int;
@@ -216,6 +216,7 @@ val init_step :
   ?check_module_exports:memory_export_rules ->
   module_reg:module_reg ->
   self:module_key ->
+  buffers ->
   Host_funcs.registry ->
   Ast.module_ ->
   extern Vector.t ->
@@ -225,6 +226,7 @@ val init_step :
 val init :
   module_reg:module_reg ->
   self:module_key ->
+  buffers ->
   Host_funcs.registry ->
   Ast.module_ ->
   extern list ->
@@ -245,14 +247,15 @@ val step :
   ?durable:Durable_storage.t ->
   module_reg ->
   config ->
+  buffers ->
   (Durable_storage.t * config) Lwt.t
 
 val config :
-  ?input:input_inst ->
-  ?output:output_inst ->
   Host_funcs.registry ->
   ?frame_arity:int32 (* The number of values returned by the computation *) ->
   module_key ->
   value Vector.t ->
   admin_instr Vector.t ->
   config
+
+val buffers : ?input:input_inst -> ?output:output_inst -> unit -> buffers
diff --git a/src/proto_alpha/lib_protocol/test/integration/test_sc_rollup_wasm.ml b/src/proto_alpha/lib_protocol/test/integration/test_sc_rollup_wasm.ml
index a56433f603b7b0e5650fff85882aa084acb227a8..7bcb0f61f788735de9fb83c60dc7247f57b588df 100644
--- a/src/proto_alpha/lib_protocol/test/integration/test_sc_rollup_wasm.ml
+++ b/src/proto_alpha/lib_protocol/test/integration/test_sc_rollup_wasm.ml
@@ -124,7 +124,7 @@ module Prover = Alpha_context.Sc_rollup.Wasm_2_0_0PVM.Make (WASM_P)
    pass. It should be updated to [16 * 1024] once the small ticks
    milestone is completed.
 *)
-let proof_size_limit = 21_488
+let proof_size_limit = 21_550
 
 let check_proof_size ~loc context input_opt s =
   let open Lwt_result_syntax in