Re: [PATCH v3 5/5] mm: userfaultfd: add UFFDIO_CONTINUE_MODE_WP to install WP PTEs

On Mon, Mar 06, 2023 at 02:50:24PM -0800, Axel Rasmussen wrote:

UFFDIO_COPY already has UFFDIO_COPY_MODE_WP, so when installing a new PTE to resolve a missing fault, one can install a write-protected one. This is useful when using UFFDIO_REGISTER_MODE_{MISSING,WP} in combination.

So, add an analogous UFFDIO_CONTINUE_MODE_WP, which does the same thing but for *minor* faults.

Update the selftest to do some very basic exercising of the new flag.

Signed-off-by: Axel Rasmussen axelrasmussen@google.com

Some mentioning on the use case would be nice. :) No objection having it.

Acked-by: Peter Xu peterx@redhat.com

Thanks,