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b=b2SxwCAXl+z/vJnA046cxZ1amLOruSa9uLUMV8rOFXG4AqCX6R9OWmpTjrhsKEAia DSlJYr5I6i9QkM74i0RYc4O/XY7yY4i4CNcJmSFwWy76yGcje4nFO9YQkE927v+DWb 11eMRvo98J8NMWSpEjydwsbkm56t6lTBlovhQxaSaNdhiXsaW4TOGtR3jwSSxQn1Kc L9P8nXnB3Sc6ysfdguKsam3YGWz2LKvdEVt7KiZvU2WZlBPZaDerjUxUBcC/l0hp8p cv+cyi5m7vYchI6w0W5UasLZ6lYaEnfi/rqyhpsrKi3xsFkyfBUAlh4PQmq8vvIiHG Rq1Nb0mzF40EQ== Date: Thu, 4 Jun 2026 01:43:12 +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 v2 4/6] UFFDIO_API.2const: Document UFFD_FEATURE_RWP{,_ASYNC} and 1 << _UFFDIO_SET_MODE Message-ID: References: <20260526134149.2831720-1-kirill@shutemov.name> <20260526134149.2831720-5-kirill@shutemov.name> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="wunyxer3z3xur6ve" Content-Disposition: inline In-Reply-To: <20260526134149.2831720-5-kirill@shutemov.name> X-Rspamd-Queue-Id: 2711014000A X-Stat-Signature: ubxfbabfkbocbnzyuau454q5sxk5sy57 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1780530197-97983 X-HE-Meta: U2FsdGVkX19oneW2bNrbtMrIjelnJSUhEQlIpRjI0XxM3WuLD3ixlGKX43ttDzAfItJeIuNp4eRF4fMsgB5DL9go4EGwA+IPIAlg/wWURRIDn1UkZeJpAHY0JVVEooEZcX1Y5VXTc9u6d5HR8Iq5BnuLEHcNa6HJ98e5Qgk9YRXPnTRz00600Ls6dNxN1ymKlyLNnf697JMVVO984c+Kcu5vnE5bnhcFpcamtaUc8vL4vvgThTD/iP0y4wd615Yh/nW+f75zss0NjeabjsaJpCtoP+hpqIkxynHqfYG6/EQjryyFfxq3sH1ipT9sX1IRiOzWeHiqJA/2L3XG4XTXD3bYVZBIb6uBi/0LGELkUzewu0jqrzrUtJOWiXGQMR0NL8CXlWTpZrO9DWVJ3Sj9mUqYzuTiqC36iv+wR+AOqqBmyInjFsnAvQDIPwXhcMri0pUUxZ7T6annzJb82vM2HYIXgc2Fw7igg9abG3z/l8UTY2uXXLKFzqvyQvf2vVqtNjtCbMuCx7LnwI9qxTwkWzLZ64lKyWKt/KvrG3BiN410aedBevGnKGZuxwYegDASi/DM722GnCiYOc3bXgGPMseIbagfUnw6WnBJ58NUFK8AS4KtQFXOnwfwapPmh8yMno8VMH6ynAuMipDcU3nyo2wAMlujCo5TYcS3Co+veneD6+3j7JIQbAIW6uS9HBR5pvafzUdTzOPD0Sdzmxvxlj1vYg4eCpFYYbmDibAgjW+XFf68xLOB8qTSSJrPhrNYCdbeaKlALEV4HU9U/xgegmZKfg1vIOAfLfj0QfNfg0kSbIiXhsfjiimReP9qp49KLIZJpI2RKI96aOUbNMpZq+uRgam5fvmVS9zCXV5x9D5DVf1+W7iHAiWcKpTnHxbGMkRUGEH41KrK+2usvkzoosJ6BaGebLcaBy6D1GF7EQR5jFn2n4Nr/EAc2SVozQl0fw3Hju16HPbj/n5HoMJ 7QqZSICU UJIS3nLzHev4Xkcd69Mdzhi2PpzBvGjI9pThME8ZCFZMkig5wtjuNV2EiC7PP0zieU7VPrAeDSvfg2D+HjCDw71g2E2WIh+SkQ/xOAEU99Wfg1uOYJPVRd0mLffKlMZilIUX5t9kW8V+25Rws2mAeHfUtfzs6wqqCu550HnjNfEnSeEhEsM8M2+QzNNXCtKOrA6VERG2JRYyFQkkWBgv2uVyJwdJpJdcacV3BnB5qER+VTYsSBtNYf7aDGPvbnl/ZDqmpzzWZcgwEYXXgkwYHM/+fjqk7e1eeAmB7YN1rBRxAL30U7F3GRPYuNGNXH1J/COSpPdFVRAcDq7KeRhc3qaESZeBnhKMXMFfiag5VTKLcKsIWznYvCi/qgQlQDsQAG9JtRL0QFmcX52oKp/IetbTmY6/Hrr4tze30lSxwgSinFMsr9VSPZEszTJ18L8TASpDmc6QIjmYVKOcYFl+M8nQBR9FRovSCUO7F Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: --wunyxer3z3xur6ve 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 v2 4/6] UFFDIO_API.2const: Document UFFD_FEATURE_RWP{,_ASYNC} and 1 << _UFFDIO_SET_MODE Message-ID: References: <20260526134149.2831720-1-kirill@shutemov.name> <20260526134149.2831720-5-kirill@shutemov.name> MIME-Version: 1.0 In-Reply-To: <20260526134149.2831720-5-kirill@shutemov.name> Hi Kiryl, On 2026-05-26T14:41:47+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. >=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 > Acked-by: Mike Rapoport (Microsoft) Thanks! I've applied the patch. Have a lovely night! Alex > --- > man/man2const/UFFDIO_API.2const | 31 +++++++++++++++++++++++++++++++ > 1 file changed, 31 insertions(+) >=20 > diff --git a/man/man2const/UFFDIO_API.2const b/man/man2const/UFFDIO_API.2= const > index e894114bb8e2..46ee7e31fed9 100644 > --- a/man/man2const/UFFDIO_API.2const > +++ b/man/man2const/UFFDIO_API.2const > @@ -213,6 +213,30 @@ .SH DESCRIPTION > 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 +258,13 @@ .SH DESCRIPTION > 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 --wunyxer3z3xur6ve Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEES7Jt9u9GbmlWADAi64mZXMKQwqkFAmogvA8ACgkQ64mZXMKQ wqlarQ//eMAt6WsJqSanByepNV8+Cstsgy3LY20DPwoH0PdSVVLpFsXpDMSntB9r 76LADHa0ruwhClGSdIQ/K8aE0E4lbbfpdMF6DAVGcCiNV/tB7Ij8l5eZWraj+Ct2 KsT1p7K4qmO5RRsDP87qUgVRPgAcYB3AOn+DouJnTV3/8c26fkSyMH6ZQQK+VzLy 2ZYd7istnBhAuxAPNt7mUyz9OwtE8R0qqS/i8fkQJYv8BA1MPxFk2uPf7GVbHAmu QX0bIXxCPHpPNfejwLsXNTONohQUROGihZyqHOzxeN2sd2CGiKhPv64A+HCOrLDA CUrGdknPQSZAVR4tiGf42Jm3ym3gd577KCTiiZprklpzzr54gQg5y60NHHsW0Ifp 8btLf6YrDFDv4xfn6Q+z9HH+Jjr4nB5uejle6vkXjcFB1n30+w4FA9nr0IG+1WPY yHTN+xgo3sTS7uQRzuY5woQGkuUvYpyzykVy+Ww0h4ObP3LGPye4SbrelJmTdoo2 SP3EQcU62qP5f3tcd8lRSbXkzAmM2RRSAqK8ge5jB7xwODbW7ED2RYjJSWNU9pVP OBUbYgHGY4aX6HKZNxyUOjLldA53dfV2rgAJv4fPsz79djXQpNI2/jRoU1JwHZVK OCCskVAkXClfLKzaLC+U5mTgDMoD0QnIBiUIG/lEv6fri6LdrP4= =2JWI -----END PGP SIGNATURE----- --wunyxer3z3xur6ve--