diff --git a/nova/virt/libvirt/cpu/core.py b/nova/virt/libvirt/cpu/core.py
index 782f028fee3c..8274236850cc 100644
--- a/nova/virt/libvirt/cpu/core.py
+++ b/nova/virt/libvirt/cpu/core.py
@@ -60,6 +60,7 @@ def set_online(core: int) -> bool:
     return get_online(core)
 
 
+@nova.privsep.sys_admin_pctxt.entrypoint
 def set_offline(core: int) -> bool:
     filesystem.write_sys(os.path.join(gen_cpu_path(core), 'online'), data='0')
     return not get_online(core)
diff --git a/releasenotes/notes/bug-2022955-eac8b0c8e42e3696.yaml b/releasenotes/notes/bug-2022955-eac8b0c8e42e3696.yaml
new file mode 100644
index 000000000000..35d8514a3c3f
--- /dev/null
+++ b/releasenotes/notes/bug-2022955-eac8b0c8e42e3696.yaml
@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    The `CPU power management`_ feature has been fixed to use privsep to avoid
+    a FileNotFound error when offlining CPUs.
+
+    .. _CPU power management: https://docs.openstack.org/nova/latest/admin/cpu-topologies.html#configuring-cpu-power-management-for-dedicated-cores