Definition max_inv mf := forall b ofs, Mem.valid_block mf b ->
                                    permission_at mf b ofs Max = Some Freeable.

Lemma sim_valid_access: forall (mf m1f : mem) (b1 b2 : block) (ofs : Z) (Hm1f: m1f = makeCurMax mf) (HmaxF: max_inv mf) (Hvalidb2: Mem.valid_block mf b2) (Halign: (4 | ofs)%Z), Mem.valid_access m1f Mint32 b2 ofs Freeable.