diff --git a/vmm/src/config.rs b/vmm/src/config.rs
index 00bf251f3..ca697c5e3 100644
--- a/vmm/src/config.rs
+++ b/vmm/src/config.rs
@@ -719,7 +719,7 @@ impl CpusConfig {
                 v.0.iter()
                     .map(|(e1, e2)| CpuAffinity {
                         vcpu: *e1,
-                        host_cpus: e2.clone(),
+                        host_cpus: e2.clone().into_boxed_slice(),
                     })
                     .collect()
             });
@@ -3694,16 +3694,16 @@ mod unit_tests {
             CpusConfig {
                 boot_vcpus: 2,
                 max_vcpus: 2,
-                affinity: Some(vec![
+                affinity: Some(Box::new([
                     CpuAffinity {
                         vcpu: 0,
-                        host_cpus: vec![0, 2],
+                        host_cpus: Box::new([0, 2]),
                     },
                     CpuAffinity {
                         vcpu: 1,
-                        host_cpus: vec![1, 3],
+                        host_cpus: Box::new([1, 3]),
                     }
-                ]),
+                ])),
                 ..Default::default()
             },
         );
diff --git a/vmm/src/cpu.rs b/vmm/src/cpu.rs
index 1f31ff61e..291f76f24 100644
--- a/vmm/src/cpu.rs
+++ b/vmm/src/cpu.rs
@@ -716,7 +716,7 @@ pub struct CpuManager {
     #[cfg_attr(target_arch = "aarch64", allow(dead_code))]
     acpi_address: Option<GuestAddress>,
     proximity_domain_per_cpu: BTreeMap<u32, u32>,
-    affinity: BTreeMap<u32, Vec<usize>>,
+    affinity: BTreeMap<u32, Box<[usize]>>,
     dynamic: bool,
     hypervisor: Arc<dyn hypervisor::Hypervisor>,
     #[cfg(feature = "sev_snp")]
diff --git a/vmm/src/vm_config.rs b/vmm/src/vm_config.rs
index 6fefc8f06..489b7e5ce 100644
--- a/vmm/src/vm_config.rs
+++ b/vmm/src/vm_config.rs
@@ -30,7 +30,7 @@ pub(crate) trait ApplyLandlock {
 #[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize)]
 pub struct CpuAffinity {
     pub vcpu: u32,
-    pub host_cpus: Vec<usize>,
+    pub host_cpus: Box<[usize]>,
 }
 
 #[derive(Clone, Debug, Default, PartialEq, Eq, Deserialize, Serialize)]
@@ -76,7 +76,7 @@ pub struct CpusConfig {
     #[serde(default = "default_cpuconfig_max_phys_bits")]
     pub max_phys_bits: u8,
     #[serde(default)]
-    pub affinity: Option<Vec<CpuAffinity>>,
+    pub affinity: Option<Box<[CpuAffinity]>>,
     #[serde(default)]
     pub features: CpuFeatures,
     #[serde(default = "default_cpusconfig_nested")]