@@ -, +, @@ 
---
--- a/hw/qxl.c	
+++ a/hw/qxl.c	
@@ -791,7 +791,9 @@ static void qxl_add_memslot(PCIQXLDevice *d, uint32_t slot_id, uint64_t delta)
            __FUNCTION__, memslot.slot_id,
            memslot.virt_start, memslot.virt_end);
 
+    qxl_unlock_iothread(&d->ssd);
     d->ssd.worker->add_memslot(d->ssd.worker, &memslot);
+    qxl_lock_iothread(&d->ssd);
     d->guest_slots[slot_id].ptr = (void*)memslot.virt_start;
     d->guest_slots[slot_id].size = memslot.virt_end - memslot.virt_start;
     d->guest_slots[slot_id].delta = delta;
--