Messages in this thread | | | Date | Sun, 28 Apr 2019 08:47:11 +0300 | From | Mike Rapoport <> | Subject | Re: [RFC PATCH 5/7] x86/mm/fault: hook up SCI verification |
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On Fri, Apr 26, 2019 at 09:42:23AM +0200, Peter Zijlstra wrote: > On Fri, Apr 26, 2019 at 12:45:52AM +0300, Mike Rapoport wrote: > > If a system call runs in isolated context, it's accesses to kernel code and > > data will be verified by SCI susbsytem. > > > > Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> > > --- > > arch/x86/mm/fault.c | 28 ++++++++++++++++++++++++++++ > > 1 file changed, 28 insertions(+) > > There's a distinct lack of touching do_double_fault(). It appears to me > that you'll instantly trigger #DF when you #PF, because the #PF handler > itself will not be able to run.
The #PF handler is able to run. On interrupt/error entry the cr3 is switched to the full kernel page tables, pretty much like PTI does for user <-> kernel transitions. It's in the patch 3.
> And then obviously you have to be very careful to make sure #DF can, > _at_all_times_ run, otherwise you'll tripple-fault and we all know what > that does. >
-- Sincerely yours, Mike.
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