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b=M9Bo/yI7d/Y+3iaOC0FmpbSUs5mfLVWWByKDGW8mSSurOYXek9ZHvcxuWd03BA80t Z/yXBGU7tkILaRTXrMGZZXuTHeeTnimx0Bjbg4MIyFMYlmIS39WbJBs/rzri/D54YT e/uFqiGYm0TTnBhixhuOvme8Df+PEAEefJf+LSOul+Qo2XC6vknrgMNM5lqmJG108J hs4NFSV0LOXlK4LUyOfbXWZEFfDwrfqXPCsXe/q7hhnivoYBKYEuKVq2Ikn9sgkYXE KgRvox2P4IDkItuvf2Ecc6FSxnoI+l0UjyubrS1ntxluEt0IrUQbelzLZA+ke5ac5B tjCh2V1+WDkzQ== Date: Tue, 26 Sep 2023 01:50:06 +0200 From: Alejandro Colomar To: Axel Rasmussen Cc: Peter Xu , linux-man@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 06/10] ioctl_userfaultfd.2: describe missing UFFDIO_API feature flags Message-ID: <4a6utza2kwlghdrgpoc2p56gfzwb4lwpp6rsqed4gaecvbfdxt@f2gw6c737te6> References: <20230919190206.388896-1-axelrasmussen@google.com> <20230919190206.388896-7-axelrasmussen@google.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="cjrue5kcslvl7m5p" Content-Disposition: inline In-Reply-To: <20230919190206.388896-7-axelrasmussen@google.com> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: BAC9F40007 X-Stat-Signature: iyj7qdi9xz4r7nzrimg6di9eo9g1aazd X-Rspam-User: X-HE-Tag: 1695685813-449 X-HE-Meta: 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 lIVunsR3 EdnGyMdsTJCxv78PrFj7N+hVGKwQr1epsCtBdS2yb5HGGcodbK8Wl/zWw2XlZIVh6wjainsRM270nWlmboBjvpUdvMBLVATf9yIx5pfR02K1nUjPTcYA7nAJ7B9jUZIA4wOdD3gjY5o9ZS7LqrJEHfmQVkrBRMjqsu110GeWk+gpNuqtHIY2UGIu8FEr6iBCSs/3UI/icvSuUnaBPYvask+31EYl4UpehqNYvtdAVDjf8LEKzAQoakY0ZSJuuxsH+vXfdwZXq4cDqI2eEWCiA+mfbwiv1p6UD7o9bHJqXDLseVpJ+02W76oEHqLIL4+tnlhgY9IaWL5eXHTAzYsXivndGyVxW2JuweYPNadbasET1P2c= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: --cjrue5kcslvl7m5p Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH 06/10] ioctl_userfaultfd.2: describe missing UFFDIO_API feature flags MIME-Version: 1.0 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. >=20 > Signed-off-by: Axel Rasmussen > --- Patch applied. Thanks, Alex > man2/ioctl_userfaultfd.2 | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) >=20 > 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 > --=20 > 2.42.0.459.ge4e396fd5e-goog >=20 --cjrue5kcslvl7m5p Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE6jqH8KTroDDkXfJAnowa+77/2zIFAmUSHK4ACgkQnowa+77/ 2zKijg//Y70CRLE5sfeTvnRPNP9o+9cOLE60z1NZTTXAVlvBpJM6ag1S6Hivd/lQ KBq3W7eOZEA5k04InXcQhLaTcuf+eeBCNgRz9oIeUvuy6yNbjo47NKT/ojX381zq j8dq6LzhPdHAJB4jmYiZJS5FAvGEOBdIzLQ0dxJPk1i2BEcLfnqOKQ0dU7g8BB6S mpEduHSlxKciyWOQNvOcl2oMsSqFDWbICejaov8zYdruEIWXS7nSJOTI3lLlYcKF YiHTLc0J0SAv00F3uygTRASFR9FQt3xzlY6ponV4JKp0LIxMMQz/U24mTM6p8wF2 zpdyuckSc5IUpr5z0iVbSSWRZb5fy1Ky5xZtsTXK9ghcSEiAvt73VZRbR6zvAtg4 3WWcJSgYCvBQYA+gCWBLq+3C/RER0MFO8GCv1gXSWZ4KoBQtnwS5MYJSm+sUwj1U BXk4Bm8EUATI1VcpJmQg5bgkyKG8kLzO9L0ONYVULBYgiYceEU2yTgXlzNGHVW4A 8OWNsqoB+AmSTuUUWcQNe1cZNz3aB/SZs0J95Zi8CntwcMCqtQBkumNY1aNJC1fQ xR9ZEHeq5PtR5jpXQYK0YovY4MO5bTCJHM9Eig+37xMOM1q2pdx9u0nWCILsfGV7 VrdWUt+3QckgLnRRnvITNa67CQ05C2wKmSaGzrnN+WeKswqfSVQ= =u08m -----END PGP SIGNATURE----- --cjrue5kcslvl7m5p--