Hi, > But I think unexpected access shouldn't be there in the 1st place, > so guard looks pretty legit at this point. > Lets see what Gerd finds out from edk2 point of view.
CPU eject happens /after/ SMM syncronisation, when CPUs are on their way back into normal mode: * The boot processor will do the cpu hotplug register writes, from SMM mode, so it obviously will be in SMM mode still. * The processor to be unplugged will be parked in a halt loop in SMM mode until the unplug completed, so that processor will be in SMM mode too. * All other processors may or may not be in SMM mode. So parallel access is possible. take care, Gerd
