On Thu, Jun 29, 2023 at 12:00:44AM +0000, Huang, Kai wrote: > The spec says it doesn't have a latency requirement, so theoretically it could > be long. SEAMCALL is a VMEXIT so it would at least cost thousands of cycles. :-( > If raw_spinlock isn't desired, I think I can introduce another function to do > this and let the caller to call it before calling tdx_cpu_enable(). E.g., we > can have below functions: > > 1) tdx_global_init() -> TDH_SYS_INIT > 2) tdx_cpu_init() -> TDH_SYS_LP_INIT > 3) tdx_enable() -> actual module initialization > > How does this sound? Ah, wait, I hadn't had enough wake-up juice, it's tdx_global_init() that did the raw_spinlock_t, but that isn't the IPI thing. Then perhaps just use a mutex to serialize things?