| Message ID | 20230919190206.388896-7-axelrasmussen@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [01/10] userfaultfd.2: briefly mention two-step feature handshake process | expand |
On Tue, Sep 19, 2023 at 12:02:02PM -0700, Axel Rasmussen wrote: > Several new features have been added to the kernel recently, and the man > page wasn't updated to describe these new features. So, add in > descriptions of any missing features. > > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> > --- Patch applied. Thanks, Alex > man2/ioctl_userfaultfd.2 | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2 > index e91a1dfc8..53b1f473f 100644 > --- a/man2/ioctl_userfaultfd.2 > +++ b/man2/ioctl_userfaultfd.2 > @@ -204,6 +204,13 @@ If this feature bit is set, > .I uffd_msg.pagefault.feat.ptid > will be set to the faulted thread ID for each page-fault message. > .TP > +.BR UFFD_FEATURE_PAGEFAULT_FLAG_WP " (since Linux 5.10)" > +If this feature bit is set, > +userfaultfd supports write-protect faults > +for anonymous memory. > +(Note that shmem / hugetlbfs support > +is indicated by a separate feature.) > +.TP > .BR UFFD_FEATURE_MINOR_HUGETLBFS " (since Linux 5.13)" > If this feature bit is set, > the kernel supports registering userfaultfd ranges > @@ -221,6 +228,22 @@ will be set to the exact page-fault address that was reported by the hardware, > and will not mask the offset within the page. > Note that old Linux versions might indicate the exact address as well, > even though the feature bit is not set. > +.TP > +.BR UFFD_FEATURE_WP_HUGETLBFS_SHMEM " (since Linux 5.19)" > +If this feature bit is set, > +userfaultfd supports write-protect faults > +for hugetlbfs and shmem / tmpfs memory. > +.TP > +.BR UFFD_FEATURE_WP_UNPOPULATED " (since Linux 6.4)" > +If this feature bit is set, > +the kernel will handle anonymous memory the same way as file memory, > +by allowing the user to write-protect unpopulated ptes. > +.TP > +.BR UFFD_FEATURE_POISON " (since Linux 6.6)" > +If this feature bit is set, > +the kernel supports resolving faults with the > +.B UFFDIO_POISON > +ioctl. > .PP > The returned > .I ioctls > -- > 2.42.0.459.ge4e396fd5e-goog >
On Tue, Sep 19, 2023 at 12:02:02PM -0700, Axel Rasmussen wrote: > Several new features have been added to the kernel recently, and the man > page wasn't updated to describe these new features. So, add in > descriptions of any missing features. > > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> with a small nit below > --- > man2/ioctl_userfaultfd.2 | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2 > index e91a1dfc8..53b1f473f 100644 > --- a/man2/ioctl_userfaultfd.2 > +++ b/man2/ioctl_userfaultfd.2 > @@ -204,6 +204,13 @@ If this feature bit is set, > .I uffd_msg.pagefault.feat.ptid > will be set to the faulted thread ID for each page-fault message. > .TP > +.BR UFFD_FEATURE_PAGEFAULT_FLAG_WP " (since Linux 5.10)" > +If this feature bit is set, > +userfaultfd supports write-protect faults > +for anonymous memory. > +(Note that shmem / hugetlbfs support > +is indicated by a separate feature.) > +.TP > .BR UFFD_FEATURE_MINOR_HUGETLBFS " (since Linux 5.13)" > If this feature bit is set, > the kernel supports registering userfaultfd ranges > @@ -221,6 +228,22 @@ will be set to the exact page-fault address that was reported by the hardware, > and will not mask the offset within the page. > Note that old Linux versions might indicate the exact address as well, > even though the feature bit is not set. > +.TP > +.BR UFFD_FEATURE_WP_HUGETLBFS_SHMEM " (since Linux 5.19)" > +If this feature bit is set, > +userfaultfd supports write-protect faults > +for hugetlbfs and shmem / tmpfs memory. > +.TP > +.BR UFFD_FEATURE_WP_UNPOPULATED " (since Linux 6.4)" > +If this feature bit is set, > +the kernel will handle anonymous memory the same way as file memory, > +by allowing the user to write-protect unpopulated ptes. Nit: s/ptes/page table entries/ > +.TP > +.BR UFFD_FEATURE_POISON " (since Linux 6.6)" > +If this feature bit is set, > +the kernel supports resolving faults with the > +.B UFFDIO_POISON > +ioctl. > .PP > The returned > .I ioctls > -- > 2.42.0.459.ge4e396fd5e-goog > >
Hi Mike, On Mon, Oct 09, 2023 at 11:45:14AM +0300, Mike Rapoport wrote: > On Tue, Sep 19, 2023 at 12:02:02PM -0700, Axel Rasmussen wrote: > > Several new features have been added to the kernel recently, and the man > > page wasn't updated to describe these new features. So, add in > > descriptions of any missing features. > > > > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> > > Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> > > with a small nit below Thanks for the reviews! > > > --- [...] > > +by allowing the user to write-protect unpopulated ptes. > > Nit: s/ptes/page table entries/ I've applied the following patch: <https://www.alejandro-colomar.es/src/alx/linux/man-pages/man-pages.git/commit/?h=contrib&id=2afbc25a7a3b1b68b638d7542a6bead7a1960a7d> Cheers, Alex
diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2 index e91a1dfc8..53b1f473f 100644 --- a/man2/ioctl_userfaultfd.2 +++ b/man2/ioctl_userfaultfd.2 @@ -204,6 +204,13 @@ If this feature bit is set, .I uffd_msg.pagefault.feat.ptid will be set to the faulted thread ID for each page-fault message. .TP +.BR UFFD_FEATURE_PAGEFAULT_FLAG_WP " (since Linux 5.10)" +If this feature bit is set, +userfaultfd supports write-protect faults +for anonymous memory. +(Note that shmem / hugetlbfs support +is indicated by a separate feature.) +.TP .BR UFFD_FEATURE_MINOR_HUGETLBFS " (since Linux 5.13)" If this feature bit is set, the kernel supports registering userfaultfd ranges @@ -221,6 +228,22 @@ will be set to the exact page-fault address that was reported by the hardware, and will not mask the offset within the page. Note that old Linux versions might indicate the exact address as well, even though the feature bit is not set. +.TP +.BR UFFD_FEATURE_WP_HUGETLBFS_SHMEM " (since Linux 5.19)" +If this feature bit is set, +userfaultfd supports write-protect faults +for hugetlbfs and shmem / tmpfs memory. +.TP +.BR UFFD_FEATURE_WP_UNPOPULATED " (since Linux 6.4)" +If this feature bit is set, +the kernel will handle anonymous memory the same way as file memory, +by allowing the user to write-protect unpopulated ptes. +.TP +.BR UFFD_FEATURE_POISON " (since Linux 6.6)" +If this feature bit is set, +the kernel supports resolving faults with the +.B UFFDIO_POISON +ioctl. .PP The returned .I ioctls
Several new features have been added to the kernel recently, and the man page wasn't updated to describe these new features. So, add in descriptions of any missing features. Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> --- man2/ioctl_userfaultfd.2 | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)