On Wed, 5 Sep 2018, Ard Biesheuvel wrote: > On 5 September 2018 at 14:56, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > On Wed, Sep 05, 2018 at 02:27:49PM +0200, Ard Biesheuvel wrote: > >> Would we still need to preserve the old memory map in that case? > > > > I thought the reason for having this was being able to know the fault is > > in an EFI area. But of course, I'm not wel versed in this whole EFI > > crapola. > > I'm not entirely sure whether that really matters. The EFI services > access the stack and can access byref/pointer arguments which are not > covered by the EFI memory map as runtime services code/data, and so > they can trigger page faults by running off the vmapped stack or > writing to const byref arguments. > > EFI runtime services using boot services regions after they are no > longer available are a known source of headaches, but I don't see why > we should restrict ourselves to such cases if we bother to wire up > fault handling specifically for EFI services calls. > > So any page or permission fault occurring in the context of a EFI > runtime services invocation should be treated the same, I think. I agree. Keep it simple. If the EFI crap fails, then assist with the reboot and otherwise just kill it. Thanks, tglx
