On Wed, Aug 18, 2021 at 09:38:30AM -0700, Yu, Yu-cheng wrote:

We can visualize the type of a mm area by looking at vma->vm_flags, e.g.

visualize?

maybe_mkwrite(), and PTE macros as lower-level operatives.  These two have
some relations but not one-to-one.  Note that a PTE in a writable area is
not always pte_write().

I have considered and implemented a shadow stack PTE either pte_write() or
not.  Making shadow stack as pte_write() results in less arch_* macros and
less confusion in copy-on-write code.  That is one more thing to consider.

Ok, even though I'm still not 100% convinced by both amluto's and your
arguments. Let's try it and see what happens...

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette