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h=Date:From:To:Cc:Subject:References:In-Reply-To; b=cOYnsB2NyJ2P4m+KDK7ynVc7doyIu+ppMdqgyBley+f5qW2Ax1KjA0bGqb65fUPsn np04KtjiGjGbU71IqOWhrd12NJQhfHQ8dT5+St/1h3VQIC5cFBgv88YJMP+dqkuneo lRSqEtN4Gq0Msh6yDefe6lLAu1o33tHI32vjsOnYVbPBQnGY2jIPlMjozdaiaACTMw 3HBoIIGDky0GtZ08Qbl1X8Vj7PjZ3JoV92PEKsBMtsVgWeAc7xqCq1+Ao/C2YzrSAx jJR0MVZQ4YIKy8Sjfg3/KWo0WVEkYH2FQxwZTfH+Z1mjqLXp3LoD1Sgxp3l7qw+tF6 dh2k+4BgA2JDw== Date: Mon, 25 May 2026 16:00:33 +0200 From: Alejandro Colomar To: Kiryl Shutsemau Cc: linux-man@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, rppt@kernel.org, peterx@redhat.com, david@kernel.org, kernel-team@meta.com, Kiryl Shutsemau Subject: Re: [PATCH man-pages v1 4/6] UFFDIO_API.2const: Document UFFD_FEATURE_RWP{,_ASYNC} and 1 << _UFFDIO_SET_MODE Message-ID: References: <20260525122816.1956804-1-kirill@shutemov.name> <20260525122816.1956804-5-kirill@shutemov.name> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="gxmzouvuofrgzmdc" Content-Disposition: inline In-Reply-To: <20260525122816.1956804-5-kirill@shutemov.name> X-Rspam-User: X-Rspamd-Queue-Id: 9AE9618000A X-Rspamd-Server: rspam03 X-Stat-Signature: wj9bx4czthu6kgb3g5kfg69ibbr314cp X-HE-Tag: 1779717638-46463 X-HE-Meta: U2FsdGVkX1/R7txnkJbyRa5Ps6T04HEQKCnVWfrqUhFMuBJW7rHBnT5NlHIw0Z9w9cT+DBJQ7DSQ2muBxSeUSdQRUfiQ4L07aBCF+tR7+jZguDd1BgxYnwlwiULfUXcuMZzGOiNVg3ml2upjYQBmuTjizPBMweG9BHAY7ZhXi2HbaNl3pcUrgxtAzY/oUSPWWhXAMmhjaYvh/XnGZSsVAPguuqlqafX0ciFwzQcmkhe6sPzdpp4ETKW/CKLuGbqhOK5YWkfZQ5eIWFOtg+VI4YMBQ7dcW94E15EWSbnOKMvKonJ7Ch65KPdlE28D/vwN9zX/k8vqemN0F6qbSwtCC8715DiPeD6webkO3icAEeBxIbRyM90c9hHmWtVVUdcx/DY+DsczD3OYtC/V+Yhc/mlGDZV8nz/qjrOkUCDVh0SqGVa6FvRd6YE/o0589PivxQpZFs7rOeG5HZVMPfLha+JrrnLLI6C34F236gEcHF+jNaCWSuZxZz4vxcZMkD8AGYvUqwh+HrysaKIk2w2zKpiTnisScDm7inuWlQwgkB0WCLnlS5u3Sjt8qdb+fXkJrpDSv3dtbcJOLuJ5n2AQfIpvl+KyuFkbqpJzWdnvU0Yt8pdMeakLX1xc+GPBoARoaRmOs1hVexztmyt+PdfPxoawtSxxtqSwAYqZoEo2Z/mBpx8yZMyzUnkah8vNVmteXvSB+7nCZQUZWc1l+6JnEjBNDkk30LNVRL1XMBiY2mArqPi8eT/o1uQoy6TbF0nuqjM0fWdQSot2WnIJnfhZRgIPYyfjIjyWFhHV6TacwEkFQ8EzchS2nkVL+a0ftUk+MXsEbDLHscoc/IskPPFXTexQqCp7oAVlb6DyAi1ZDbbeTU6izeK+q+/ssUII4MnQalcpNboxQW0Scq9ua1wLiemMIvVNo3aqCUeGk+UvJZbVo7TvkMtV1Gh7tZLGESNp0TvxMyzbdOME+3Q6+D/ Kh4HnkaN dSZp36SRR5OeDdFehj29lQdgPpESOdT3Uc4uYrYop7OCxzB7+/2qhAWf7pzZ8f//m/CRNrQiAVPqbQ7qb0cwSQfvAOb8DhFr9GJo0ONRhgNsXEure+P/QtwKmAp3B0FJwijNTAj3GnWrLpYvnefFR3ueeS4foqHZoSliu/Z+zpC+hEUaJjHTpkMJDp8Jrast8EHBwtZF0hZLkZ56e0ddg4+Sg0ckYPx79y9Vxn4p0NtasM0Z3PwsasZaUX856YtE2D/h7Ns6EwBsaszCWmYe2iAOpVMzVkYXMzOHrEvLEdlkVusy+IPewcFc+vu5oqnwta4kLsRM3AlUqUV/tpuLTH2IFD/Fr8A9izjGIP0mpUl41yZDlJHdRAH6CbxNFgzN3Rk8nnUhZS5qD/itYErpoqWR1i0Tcz8ahavmohz5iJU7OLCp/1JrSDkgy5Mo3ygG6slqyF98tkz3ZeOeB4B73q4VyxLFOsr6+IZb9 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: --gxmzouvuofrgzmdc Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable From: Alejandro Colomar To: Kiryl Shutsemau Cc: linux-man@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, rppt@kernel.org, peterx@redhat.com, david@kernel.org, kernel-team@meta.com, Kiryl Shutsemau Subject: Re: [PATCH man-pages v1 4/6] UFFDIO_API.2const: Document UFFD_FEATURE_RWP{,_ASYNC} and 1 << _UFFDIO_SET_MODE Message-ID: References: <20260525122816.1956804-1-kirill@shutemov.name> <20260525122816.1956804-5-kirill@shutemov.name> MIME-Version: 1.0 In-Reply-To: <20260525122816.1956804-5-kirill@shutemov.name> Hi Kiryl, On 2026-05-25T13:28:14+0100, Kiryl Shutsemau wrote: > Add the two RWP feature bits introduced in Linux 7.2: >=20 > UFFD_FEATURE_RWP gates UFFDIO_REGISTER_MODE_RWP and the > UFFDIO_RWPROTECT(2const) ioctl. > UFFD_FEATURE_RWP_ASYNC in-kernel resolution of RWP faults without > delivering a notification; requires > UFFD_FEATURE_RWP to be set in the same > UFFDIO_API call. >=20 > Also document 1 << _UFFDIO_SET_MODE in argp->ioctls, the > file-descriptor-level bit that advertises UFFDIO_SET_MODE(2const) for > toggling UFFD_FEATURE_RWP_ASYNC at runtime; it is independent of any > registered range. Would you mind separating these into 3 patches? Thanks! >=20 > The existing page intro already describes UFFDIO_API returning EINVAL > on unsupported feature bits and the temporary-uffd probe pattern, so > the new TP entries do not re-state that. >=20 > Signed-off-by: Kiryl Shutsemau Have a lovely day! Alex > --- > man/man2const/UFFDIO_API.2const | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) >=20 > diff --git a/man/man2const/UFFDIO_API.2const b/man/man2const/UFFDIO_API.2= const > index e894114bb8e2..d2819f009f97 100644 > --- a/man/man2const/UFFDIO_API.2const > +++ b/man/man2const/UFFDIO_API.2const > @@ -213,6 +213,28 @@ If this feature bit is set, > the kernel supports resolving faults with the > .B UFFDIO_MOVE > ioctl. > +.TP > +.BR UFFD_FEATURE_RWP " (since Linux 7.2)" > +If this feature bit is set, > +the kernel supports read-write protection tracking, and the > +.B UFFDIO_REGISTER_MODE_RWP > +registration mode and the > +.B UFFDIO_RWPROTECT > +ioctl become available. > +.TP > +.BR UFFD_FEATURE_RWP_ASYNC " (since Linux 7.2)" > +If this feature bit is set, > +the kernel will resolve read-write protect faults in place without > +delivering a notification, automatically restoring page permissions and > +letting the faulted thread continue. > +This bit requires > +.B UFFD_FEATURE_RWP > +to be set in the same > +.B UFFDIO_API > +call. > +The async mode can also be toggled at runtime using the > +.BR UFFDIO_SET_MODE (2const) > +ioctl. > .P > The returned > .I argp->ioctls > @@ -234,6 +256,13 @@ operation is supported. > The > .B UFFDIO_UNREGISTER > operation is supported. > +.TP > +.BR "1 << _UFFDIO_SET_MODE" " (since Linux 7.2)" > +The > +.B UFFDIO_SET_MODE > +operation is supported. > +This is a file-descriptor-level ioctl and is reported once per > +userfaultfd, independent of any registered range. > .SH RETURN VALUE > On success, > 0 is returned. > --=20 > 2.54.0 >=20 >=20 --=20 --gxmzouvuofrgzmdc Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEES7Jt9u9GbmlWADAi64mZXMKQwqkFAmoUVgEACgkQ64mZXMKQ wqk1Jg/9Fz8ASGTokbYOX1XSVWGS1dHbPMc3pwu3Xy8EFHoB6LL2jvWzy6Uoo/0M e2L3AXQ2jzfHmaS4kUR6R3X3QUl49IL0pvWXDjeJu3orddNbHjN/bjEyeCdBlsTc McIj+OufpXN+pLiRzDr0KPVvt6VqIM0ThXMA5LcJuvnhAnkuLFl91w7h9L3JjPi2 4vT2qvdXY0jw7HVfyuovxMGIC8FdQyTfbehKnDEA5woXTu7UfvtWY5xtjUB7+DxC iQ20JDm7tvAX5r5Xa7URrsph4+GC1mIeHWr1nkyjokKLeb5qnQT5h6tsxl4DiDvD nsFqITLT3dtYyLBKN2OcvSe5OC0yzAEYaGBNd3hjTlrHHbVSqIsO7qotrokyoziG AgIEkLZnDSg/plpc1AQS/f/wzm643t87BewAdUsEKldz7FKj/JVwP6S6l1/W4/at 8OO+yFAOub1NbV2fcZSrFr9K4I/MdXmPvXNhSO1Al9Uamq3H/SlKZ92N8Ahn/sdu BEVvAsQspTsW288M+h87mYEgTxMCAmz6nwGjLg/n/Tsp8Vg21rDhSOkrBYFrO9TE jDweNLIQ8YGon7eHjZVnoc3R7PGnsiPC8qFF/WyWfXvXRuNs0VcKx8JbfpWfyNmp 4V0VMle3s8rap+juLrN3I6mvbA2UXd3+KD0lkgjTQuwKc0rKQFU= =zhYn -----END PGP SIGNATURE----- --gxmzouvuofrgzmdc--