On Wed, Mar 18, 2020 at 06:11:24PM -0700, Sean Christopherson wrote: > Modify the %rsp fixup after returning from the exit handler to be > relative instead of absolute to avoid clobbering any %rsp adjustments > made by the exit handler, e.g. if the exit handler modifies the stack > prior to re-entering the enclave. > > Reported-by: Nathaniel McCallum <npmccallum@xxxxxxxxxx> > Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > --- > > I'm on the fence as to whether or not this is a good idea. It's not super > painful, but it's not exactly standard/obvious code. Part of me thinks > its a bug to not let the exit handler manipulate %rsp, the other part of > me thinks it's straight up crazy :-) After some hours of processing this, I think this makes sense. It makes the interface more robust. This is not printf(). /Jarkko
