diff --git a/devices/src/ivshmem.rs b/devices/src/ivshmem.rs
index fff48a72c..98291c74e 100644
--- a/devices/src/ivshmem.rs
+++ b/devices/src/ivshmem.rs
@@ -217,7 +217,7 @@ impl BusDevice for IvshmemDevice {
 impl PciDevice for IvshmemDevice {
     fn allocate_bars(
         &mut self,
-        _allocator: &Arc<Mutex<SystemAllocator>>,
+        _allocator: &mut SystemAllocator,
         mmio32_allocator: &mut AddressAllocator,
         mmio64_allocator: &mut AddressAllocator,
         resources: Option<Vec<Resource>>,
diff --git a/devices/src/pvmemcontrol.rs b/devices/src/pvmemcontrol.rs
index 06e0e2492..d4b37456b 100644
--- a/devices/src/pvmemcontrol.rs
+++ b/devices/src/pvmemcontrol.rs
@@ -5,7 +5,7 @@
 
 use std::collections::HashMap;
 use std::ffi::CString;
-use std::sync::{Arc, Barrier, Mutex, RwLock};
+use std::sync::{Arc, Barrier, RwLock};
 use std::{io, result};
 
 use log::{debug, warn};
@@ -722,7 +722,7 @@ impl PciDevice for PvmemcontrolPciDevice {
 
     fn allocate_bars(
         &mut self,
-        _allocator: &Arc<Mutex<SystemAllocator>>,
+        _allocator: &mut SystemAllocator,
         mmio32_allocator: &mut AddressAllocator,
         _mmio64_allocator: &mut AddressAllocator,
         resources: Option<Vec<Resource>>,
diff --git a/devices/src/pvpanic.rs b/devices/src/pvpanic.rs
index 0451da1a0..9540a9125 100644
--- a/devices/src/pvpanic.rs
+++ b/devices/src/pvpanic.rs
@@ -5,7 +5,7 @@
 
 use std::any::Any;
 use std::result;
-use std::sync::{Arc, Barrier, Mutex};
+use std::sync::{Arc, Barrier};
 
 use anyhow::anyhow;
 use event_monitor::event;
@@ -174,7 +174,7 @@ impl PciDevice for PvPanicDevice {
 
     fn allocate_bars(
         &mut self,
-        _allocator: &Arc<Mutex<SystemAllocator>>,
+        _allocator: &mut SystemAllocator,
         mmio32_allocator: &mut AddressAllocator,
         _mmio64_allocator: &mut AddressAllocator,
         resources: Option<Vec<Resource>>,
diff --git a/pci/src/device.rs b/pci/src/device.rs
index 3a23ea777..29c89b8c4 100644
--- a/pci/src/device.rs
+++ b/pci/src/device.rs
@@ -5,7 +5,7 @@
 // SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
 
 use std::any::Any;
-use std::sync::{Arc, Barrier, Mutex};
+use std::sync::{Arc, Barrier};
 use std::{io, result};
 
 use serde::{Deserialize, Serialize};
@@ -49,7 +49,7 @@ pub trait PciDevice: Send {
     /// returns an address. Returns a Vec of (GuestAddress, GuestUsize) tuples.
     fn allocate_bars(
         &mut self,
-        _allocator: &Arc<Mutex<SystemAllocator>>,
+        _allocator: &mut SystemAllocator,
         _mmio32_allocator: &mut AddressAllocator,
         _mmio64_allocator: &mut AddressAllocator,
         _resources: Option<Vec<Resource>>,
diff --git a/pci/src/vfio.rs b/pci/src/vfio.rs
index f1d22ff63..53c77a95c 100644
--- a/pci/src/vfio.rs
+++ b/pci/src/vfio.rs
@@ -602,7 +602,7 @@ impl VfioCommon {
     #[allow(unused_variables)]
     pub(crate) fn allocate_bars(
         &mut self,
-        allocator: &Arc<Mutex<SystemAllocator>>,
+        allocator: &mut SystemAllocator,
         mmio32_allocator: &mut AddressAllocator,
         mmio64_allocator: &mut AddressAllocator,
         resources: Option<&[Resource]>,
@@ -741,8 +741,6 @@ impl VfioCommon {
                 PciBarRegionType::IoRegion => {
                     // The address needs to be 4 bytes aligned.
                     allocator
-                        .lock()
-                        .unwrap()
                         .allocate_io_addresses(restored_bar_addr, region_size, Some(0x4))
                         .ok_or(PciDeviceError::IoAllocationFailed(region_size))?
                 }
@@ -1852,7 +1850,7 @@ const PCI_ROM_EXP_BAR_INDEX: usize = 12;
 impl PciDevice for VfioPciDevice {
     fn allocate_bars(
         &mut self,
-        allocator: &Arc<Mutex<SystemAllocator>>,
+        allocator: &mut SystemAllocator,
         mmio32_allocator: &mut AddressAllocator,
         mmio64_allocator: &mut AddressAllocator,
         resources: Option<Vec<Resource>>,
diff --git a/pci/src/vfio_user.rs b/pci/src/vfio_user.rs
index 248f87272..456047d42 100644
--- a/pci/src/vfio_user.rs
+++ b/pci/src/vfio_user.rs
@@ -391,7 +391,7 @@ impl Vfio for VfioUserClientWrapper {
 impl PciDevice for VfioUserPciDevice {
     fn allocate_bars(
         &mut self,
-        allocator: &Arc<Mutex<SystemAllocator>>,
+        allocator: &mut SystemAllocator,
         mmio32_allocator: &mut AddressAllocator,
         mmio64_allocator: &mut AddressAllocator,
         resources: Option<Vec<Resource>>,
diff --git a/virtio-devices/src/transport/pci_device.rs b/virtio-devices/src/transport/pci_device.rs
index dd54472d3..36975e3f7 100644
--- a/virtio-devices/src/transport/pci_device.rs
+++ b/virtio-devices/src/transport/pci_device.rs
@@ -978,7 +978,7 @@ impl PciDevice for VirtioPciDevice {
 
     fn allocate_bars(
         &mut self,
-        _allocator: &Arc<Mutex<SystemAllocator>>,
+        _allocator: &mut SystemAllocator,
         mmio32_allocator: &mut AddressAllocator,
         mmio64_allocator: &mut AddressAllocator,
         resources: Option<Vec<Resource>>,
diff --git a/vmm/src/device_manager.rs b/vmm/src/device_manager.rs
index b6d35964f..edb8b76af 100644
--- a/vmm/src/device_manager.rs
+++ b/vmm/src/device_manager.rs
@@ -3995,7 +3995,7 @@ impl DeviceManager {
             .lock()
             .unwrap()
             .allocate_bars(
-                &self.address_manager.allocator,
+                &mut self.address_manager.allocator.lock().unwrap(),
                 &mut self.pci_segments[segment_id as usize]
                     .mem32_allocator
                     .lock()