diff --git a/afl/src/feedbacks/mod.rs b/afl/src/feedbacks/mod.rs
index b7f2fd4e7b..8206a73f5d 100644
--- a/afl/src/feedbacks/mod.rs
+++ b/afl/src/feedbacks/mod.rs
@@ -189,7 +189,7 @@ where
         let mut interesting = 0;
         // TODO optimize
         let observer = observers.match_name_type::<O>(&self.name).unwrap();
-        let size = observer.map().len();
+        let size = observer.usable_count();
         for i in 0..size {
             let history = self.history_map[i];
             let item = observer.map()[i];
diff --git a/afl/src/observers/mod.rs b/afl/src/observers/mod.rs
index adeae619c8..c57643dc0f 100644
--- a/afl/src/observers/mod.rs
+++ b/afl/src/observers/mod.rs
@@ -2,7 +2,7 @@ extern crate num;
 
 use serde::{Deserialize, Serialize};
 
-use crate::serde_anymap::ArrayMut;
+use crate::serde_anymap::{Cptr, ArrayMut};
 use crate::tuples::{MatchNameAndType, MatchType, Named, TupleList};
 use crate::AflError;
 
@@ -92,6 +92,11 @@ where
     /// Get the map (mutable)
     fn map_mut(&mut self) -> &mut [T];
 
+    /// Get the number of usable entries in the map (all by default)
+    fn usable_count(&self) -> usize {
+        self.map().len()
+    }
+
     /// Get the initial value for reset()
     fn initial(&self) -> T;
 
@@ -106,7 +111,8 @@ where
     fn reset_map(&mut self) -> Result<(), AflError> {
         // Normal memset, see https://rust.godbolt.org/z/Trs5hv
         let initial = self.initial();
-        for i in self.map_mut().iter_mut() {
+        let cnt = self.usable_count();
+        for i in self.map_mut()[0..cnt].iter_mut() {
             *i = initial;
         }
         Ok(())
@@ -204,6 +210,102 @@ where
     }
 }
 
+#[derive(Serialize, Deserialize)]
+#[serde(bound = "T: serde::de::DeserializeOwned")]
+pub struct VariableMapObserver<T>
+where
+    T: Default + Copy + 'static + serde::Serialize + serde::de::DeserializeOwned,
+{
+    map: ArrayMut<T>,
+    size: Cptr<usize>,
+    initial: T,
+    name: String,
+}
+
+impl<T> Observer for VariableMapObserver<T>
+where
+    T: Default + Copy + 'static + serde::Serialize + serde::de::DeserializeOwned,
+{
+    #[inline]
+    fn reset(&mut self) -> Result<(), AflError> {
+        self.reset_map()
+    }
+}
+
+impl<T> Named for VariableMapObserver<T>
+where
+    T: Default + Copy + 'static + serde::Serialize + serde::de::DeserializeOwned,
+{
+    #[inline]
+    fn name(&self) -> &str {
+        self.name.as_str()
+    }
+}
+
+impl<T> MapObserver<T> for VariableMapObserver<T>
+where
+    T: Default + Copy + 'static + serde::Serialize + serde::de::DeserializeOwned,
+{
+    #[inline]
+    fn map(&self) -> &[T] {
+        self.map.as_slice()
+    }
+
+    #[inline]
+    fn map_mut(&mut self) -> &mut [T] {
+        self.map.as_mut_slice()
+    }
+    
+    #[inline]
+    fn usable_count(&self) -> usize {
+        *self.size.as_ref()
+    }
+
+    #[inline]
+    fn initial(&self) -> T {
+        self.initial
+    }
+
+    #[inline]
+    fn initial_mut(&mut self) -> &mut T {
+        &mut self.initial
+    }
+
+    #[inline]
+    fn set_initial(&mut self, initial: T) {
+        self.initial = initial
+    }
+}
+
+impl<T> VariableMapObserver<T>
+where
+    T: Default + Copy + 'static + serde::Serialize + serde::de::DeserializeOwned,
+{
+    /// Creates a new MapObserver
+    pub fn new(name: &'static str, map: &'static mut [T], size: &usize) -> Self {
+        let initial = if map.len() > 0 { map[0] } else { T::default() };
+        Self {
+            map: ArrayMut::Cptr((map.as_mut_ptr(), map.len())),
+            size: Cptr::Cptr(size as *const _),
+            name: name.into(),
+            initial,
+        }
+    }
+
+    /// Creates a new MapObserver from a raw pointer
+    pub fn new_from_ptr(name: &'static str, map_ptr: *mut T, max_len: usize, size_ptr: *const usize) -> Self {
+        unsafe {
+            let initial = if max_len > 0 { *map_ptr } else { T::default() };
+            VariableMapObserver {
+                map: ArrayMut::Cptr((map_ptr, max_len)),
+                size: Cptr::Cptr(size_ptr),
+                name: name.into(),
+                initial,
+            }
+        }
+    }
+}
+
 /*
 #[cfg(feature = "std")]
 #[cfg(test)]
diff --git a/afl/src/serde_anymap.rs b/afl/src/serde_anymap.rs
index 4cab18cb85..d5993b8c7a 100644
--- a/afl/src/serde_anymap.rs
+++ b/afl/src/serde_anymap.rs
@@ -629,7 +629,84 @@ impl<'a, T: Sized> SliceMut<'a, T> {
     }
 }
 
-pub enum Array<T: Sized + serde::Serialize> {
+pub enum Cptr<T: Sized> {
+    Cptr(*const T),
+    Owned(Box<T>),
+}
+
+impl<T: Sized + serde::Serialize> serde::Serialize for Cptr<T> {
+    fn serialize<S>(&self, se: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        self.as_ref().serialize(se)
+    }
+}
+
+impl<'de, T: Sized + serde::de::DeserializeOwned> Deserialize<'de> for Cptr<T>
+where
+    Vec<T>: Deserialize<'de>,
+{
+    fn deserialize<D>(de: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        Deserialize::deserialize(de).map(Cptr::Owned)
+    }
+}
+
+impl<T: Sized> Cptr<T> {
+    pub fn as_ref(&self) -> &T {
+        match self {
+            Cptr::Cptr(p) => unsafe { p.as_ref().unwrap() },
+            Cptr::Owned(v) => v.as_ref(),
+        }
+    }
+}
+
+pub enum CptrMut<T: Sized> {
+    Cptr(*mut T),
+    Owned(Box<T>),
+}
+
+impl<T: Sized + serde::Serialize> serde::Serialize for CptrMut<T> {
+    fn serialize<S>(&self, se: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        self.as_ref().serialize(se)
+    }
+}
+
+impl<'de, T: Sized + serde::de::DeserializeOwned> Deserialize<'de> for CptrMut<T>
+where
+    Vec<T>: Deserialize<'de>,
+{
+    fn deserialize<D>(de: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        Deserialize::deserialize(de).map(CptrMut::Owned)
+    }
+}
+
+impl<T: Sized> CptrMut<T> {
+    pub fn as_ref(&self) -> &T {
+        match self {
+            CptrMut::Cptr(p) => unsafe { p.as_ref().unwrap() },
+            CptrMut::Owned(b) => b.as_ref(),
+        }
+    }
+
+    pub fn as_mut(&mut self) -> &mut T {
+        match self {
+            CptrMut::Cptr(p) => unsafe { p.as_mut().unwrap() },
+            CptrMut::Owned(b) => b.as_mut(),
+        }
+    }
+}
+
+pub enum Array<T: Sized> {
     Cptr((*const T, usize)),
     Owned(Vec<T>),
 }
@@ -655,7 +732,7 @@ where
     }
 }
 
-impl<T: Sized + serde::Serialize> Array<T> {
+impl<T: Sized> Array<T> {
     pub fn as_slice(&self) -> &[T] {
         match self {
             Array::Cptr(p) => unsafe { core::slice::from_raw_parts(p.0, p.1) },
@@ -664,7 +741,7 @@ impl<T: Sized + serde::Serialize> Array<T> {
     }
 }
 
-pub enum ArrayMut<T: Sized + serde::Serialize> {
+pub enum ArrayMut<T: Sized> {
     Cptr((*mut T, usize)),
     Owned(Vec<T>),
 }
@@ -690,7 +767,7 @@ where
     }
 }
 
-impl<T: Sized + serde::Serialize> ArrayMut<T> {
+impl<T: Sized> ArrayMut<T> {
     pub fn as_slice(&self) -> &[T] {
         match self {
             ArrayMut::Cptr(p) => unsafe { core::slice::from_raw_parts(p.0, p.1) },
diff --git a/fuzzers/qemufuzzer/src/lib.rs b/fuzzers/qemufuzzer/src/lib.rs
index 38f83b434a..7454f25d3b 100644
--- a/fuzzers/qemufuzzer/src/lib.rs
+++ b/fuzzers/qemufuzzer/src/lib.rs
@@ -14,7 +14,7 @@ use afl::feedbacks::MaxMapFeedback;
 use afl::generators::RandPrintablesGenerator;
 use afl::mutators::scheduled::HavocBytesMutator;
 use afl::mutators::HasMaxSize;
-use afl::observers::StdMapObserver;
+use afl::observers::VariableMapObserver;
 use afl::stages::mutational::StdMutationalStage;
 use afl::tuples::tuple_list;
 use afl::utils::StdRand;
@@ -66,7 +66,7 @@ pub extern "C" fn fuzz_main_loop() {
     }
     println!("We're a client, let's fuzz :)");
 
-    let edges_observer = StdMapObserver::new_from_ptr(&NAME_COV_MAP, unsafe { fuzz_hitcounts_map.as_mut_ptr() }, unsafe { fuzz_edges_id });
+    let edges_observer = VariableMapObserver::new(&NAME_COV_MAP, unsafe { &mut fuzz_hitcounts_map }, unsafe { &fuzz_edges_id });
     let edges_feedback = MaxMapFeedback::new_with_observer(&NAME_COV_MAP, &edges_observer);
 
     let executor = InMemoryExecutor::new("QEMUFuzzer", harness, tuple_list!(edges_observer));