On 15/04/2015 15:58, Gerd Hoffmann wrote: > The "A Tour Beyond BIOS Implementing S3 Resume with EDKII" white paper > lists "Lock SMM. This must be done to maintain SMM integrity." as todo > list item for the edk2 resume code path (page 18). > > So it seems to me it is the job of the firmware to re-lock smm after S3 > (and before handing control back to the OS, obviously).
Right, however "D_LCK can be set to 1 via a normal configuration space write but can only be cleared by a Full Reset." A Full Reset is the PLTRST# pin, which is asserted by the south bridge during power-up and during CF9h reset. S3 doesn't seem to be included. My reading of the EDK2 whitepaper is that this may vary for other chipsets. Paolo
