/* * Bring down a VCPU (i.e., make it non-runnable). * There are a few caveats that callers should observe: * 1. This operation may return, and VCPU_is_up may return false, before the * VCPU stops running (i.e., the command is asynchronous). It is a good * idea to ensure that the VCPU has entered a non-critical loop before * bringing it down. Alternatively, this operation is guaranteed * synchronous if invoked by the VCPU itself. * 2. After a VCPU is initialised, there is currently no way to drop all its * references to domain memory. Even a VCPU that is down still holds * memory references via its pagetable base pointer and GDT. It is good * practise to move a VCPU onto an 'idle' or default page table, LDT and * GDT before bringing it down. */