On Thu, Aug 30, 2018 at 6:30 PM Linus Torvalds <torva...@linux-foundation.org> wrote: > > On Thu, Aug 30, 2018 at 2:45 PM Tony Luck <tony.l...@intel.com> wrote: > > > > Fix is to move one step at a time. First mark the page not present > > (using the decoy address). Then it is safe to use the actual address > > of the 1:1 mapping to mark it "uc", and finally as present. > > Can't we do it in one step, but make sure that he clflush gets the real > address? >
I'd like to, but I'd need to have a way to mark the address as needing fixing as it gets passed from set_memory_uc() to _set_memory_uc() to change_page_attr_set() to change_page_attr_set_clear() Just checking "do we have a non-canonical address" at the bottom of that call stack and flipping bit 63 back on again seems like a bad idea. But adding extra flag arguments is majorly ugly too. -Tony
