diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index f016e8b3f6223256b21835458beb3063496a4eb3..416ab5b5dfebc5557bf1ebb55551ada7f09a508f 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -3643,3 +3643,30 @@ qemuDomainGetMlockLimitBytes(virDomainDefPtr def)
 
     return memKB << 10;
 }
+
+
+/**
+ * @def: domain definition
+ *
+ * Returns ture if the locked memory limit needs to be set or updated due to
+ * configuration or passthrough devices.
+ * */
+bool
+qemuDomainRequiresMlock(virDomainDefPtr def)
+{
+    size_t i;
+
+    if (def->mem.locked)
+        return true;
+
+    for (i = 0; i < def->nhostdevs; i++) {
+        virDomainHostdevDefPtr dev = def->hostdevs[i];
+
+        if (dev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS &&
+            dev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI &&
+            dev->source.subsys.u.pci.backend == VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO)
+            return true;
+    }
+
+    return false;
+}
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index e34370b08b56eaebed915103ee22115f896e8af1..4be998c27d4ba392c3010a30c8969f2d8fb024f4 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -483,5 +483,6 @@ int qemuDomainUpdateCurrentMemorySize(virQEMUDriverPtr driver,
                                       virDomainObjPtr vm);
 
 unsigned long long qemuDomainGetMlockLimitBytes(virDomainDefPtr def);
+bool qemuDomainRequiresMlock(virDomainDefPtr def);
 
 #endif /* __QEMU_DOMAIN_H__ */
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index e7fc036471c21abe639fdf646f8c3b77a12c9dc9..b02e9050f2d9a2c25e02a759ecbc4f02b9e744e3 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -1768,6 +1768,7 @@ qemuDomainAttachMemory(virQEMUDriverPtr driver,
     virJSONValuePtr props = NULL;
     virObjectEventPtr event;
     bool fix_balloon = false;
+    bool mlock = false;
     int id;
     int ret = -1;
 
@@ -1802,16 +1803,26 @@ qemuDomainAttachMemory(virQEMUDriverPtr driver,
         goto cleanup;
     }
 
+    mlock = qemuDomainRequiresMlock(vm->def);
+
+    if (mlock &&
+        virProcessSetMaxMemLock(vm->pid,
+                                qemuDomainGetMlockLimitBytes(vm->def)) < 0) {
+        mlock = false;
+        virJSONValueFree(props);
+        goto removedef;
+    }
+
     qemuDomainObjEnterMonitor(driver, vm);
     if (qemuMonitorAddObject(priv->mon, backendType, objalias, props) < 0)
-        goto removedef;
+        goto exit_monitor;
 
     if (qemuMonitorAddDevice(priv->mon, devstr) < 0) {
         virErrorPtr err = virSaveLastError();
         ignore_value(qemuMonitorDelObject(priv->mon, objalias));
         virSetError(err);
         virFreeError(err);
-        goto removedef;
+        goto exit_monitor;
     }
 
     if (qemuDomainObjExitMonitor(driver, vm) < 0) {
@@ -1845,17 +1856,27 @@ qemuDomainAttachMemory(virQEMUDriverPtr driver,
     virDomainMemoryDefFree(mem);
     return ret;
 
- removedef:
+ exit_monitor:
     if (qemuDomainObjExitMonitor(driver, vm) < 0) {
         mem = NULL;
         goto audit;
     }
 
+ removedef:
     if ((id = virDomainMemoryFindByDef(vm->def, mem)) >= 0)
         mem = virDomainMemoryRemove(vm->def, id);
     else
         mem = NULL;
 
+    /* reset the mlock limit */
+    if (mlock) {
+        virErrorPtr err = virSaveLastError();
+        ignore_value(virProcessSetMaxMemLock(vm->pid,
+                                             qemuDomainGetMlockLimitBytes(vm->def)));
+        virSetError(err);
+        virFreeError(err);
+    }
+
     goto audit;
 }
 
@@ -2947,6 +2968,12 @@ qemuDomainRemoveMemoryDevice(virQEMUDriverPtr driver,
         virDomainMemoryRemove(vm->def, idx);
 
     virDomainMemoryDefFree(mem);
+
+    /* decrease the mlock limit after memory unplug if necessary */
+    if (qemuDomainRequiresMlock(vm->def))
+        ignore_value(virProcessSetMaxMemLock(vm->pid,
+                                             qemuDomainGetMlockLimitBytes(vm->def)));
+
     return 0;
 }