From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DCEA73876B0 for ; Mon, 25 May 2026 14:00:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779717639; cv=none; b=gxYB4Wfb1DFtw2oRsbXrnXuMUXy1+do1D/gd2XTGaQDK7vOdAD99UAbiRTvP5A4PrkpWaOytz/A+U23CMsU4zEObLPV19J1SdS3gYj09tVzZP1trCml3VCbDgW8CVIbsceWcDHPKZaNEs5378NF2rpPRSHHbBzhJmrR15N1B8S8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779717639; c=relaxed/simple; bh=2l6z0Nndwq8mjFrvcLbQrc47COC9zO/Ii5VaGestSuA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NrrBbWefAwKqMppUGDv2wS7JkUeAQSBkw0xP5HVl+5P14uZ02wagSCpIT7OYwyHJAYJhADFWW9tbw5IimIr4kVHBMgZBnw8Ui4SEaOSpx7X7dpZ9oHw7VbMbszMKDyBWalLOP2x35dc4a2vzeskl8tpPTg5ISXbKbcGOEIzWT7w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cOYnsB2N; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cOYnsB2N" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9DE811F000E9; Mon, 25 May 2026 14:00:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779717637; bh=Y4tNzb+fLW4HUOsn5CL/+iaMht1iOF7Ts+XiT9xffng=; 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> Precedence: bulk X-Mailing-List: linux-man@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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> --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--