Re: [PATCH v7 1/4] userfaultfd: Add UFFD WP Async support

[Peter Xu]

On Mon, Jan 23, 2023 at 03:11:20PM +0500, Muhammad Usama Anjum wrote:
> > One thing worth mention is, I think for async wp it doesn't need to be
> > restricted by UFFD_USER_MODE_ONLY, because comparing to the sync messages
> > it has no risk of being utilized for malicious purposes.
> I think with updated handling path updated in do_wp_page() and
> wp_huge_pmd() in version, UFFD_USER_MODE_ONLY will not affect us.

This is more or less a comment for the design, the new code should work (by
bypassing handle_userfaultfd(), where this bit was checked).

We'll need an man page update if this feature will be merged [1], and if so
it'll need to be updated for the UFFD_USER_MODE_ONLY section regarding to
async uffd-wp support too.  I think that can also be worked out after the
series being accepted first, so just a heads up.

[1] https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git

-- 
Peter Xu