Re: [PATCH] intel_txt: add s3 userspace memory integrity verification

[Pavel Machek <pavel@ucw.cz>]

> > > +
> > > +   ret = tboot_pre_stack_switch();
> > > +   if (!ret) {
> > > +           tboot_switch_stack_call(tboot_do_suspend_lowlevel_call,
> > > +                                   (u64)new_stack_ptr);
> >
> > ...and here you add requirements to suspend_lowlevel that were not
> > there before. ("May not act on unchecksummed memory"), without
> > documenting them.
> 
> Really the only requirement is (as discussed in the previous thread) that it only use code and data within [_text, _end - _text]--do you think that this really needs to be called out?  do_suspend_lowlevel() is a very simple function that has just the one (resume path) call to another simple function--it doesn't seem likely that it would violate this.
> 

Resume code is already pretty tricky, and you add yet another layer of
trickery. Yes, it needs to be properly documented.

And... how does it interact with restore_processor_state? I don't
think do_suspend_lowlevel is as simple as you think...
									Pavel
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