On Mon, Apr 10 2023 at 01:14, Xin Li wrote: > Allow single-step trap and NMI when starting a new thread, thus once > the new thread returns to ring3, single-step trap and NMI are both > enabled immediately. > > High-order 48 bits above the lowest 16 bit CS are discarded by the > legacy IRET instruction, thus can be set unconditionally, even when > FRED is not enabled. I assume this has been validated to be true on _all_ CPU incarnations of _all_ x86 vendors. If so, then please document it. If not, then go back to the drawing board. Thanks, tglx