On Tue, Jun 27, 2023 at 02:12:49AM +1200, Kai Huang wrote: > @@ -1113,6 +1115,17 @@ static int init_tdx_module(void) > */ > wbinvd_on_all_cpus(); > > + /* > + * Starting from this point the system may have TDX private > + * memory. Make it globally visible so tdx_reset_memory() only > + * reads TDMRs/PAMTs when they are stable. > + * > + * Note using atomic_inc_return() to provide the explicit memory > + * ordering isn't mandatory here as the WBINVD above already > + * does that. Compiler barrier isn't needed here either. > + */ > + atomic_inc_return(&tdx_may_has_private_mem); Why do we need atomics at all here? Writers seems serialized with tdx_module_lock and reader accesses the variable when all CPUs, but one is down and cannot race. Hm? -- Kiryl Shutsemau / Kirill A. Shutemov
