From patchwork Tue Apr 27 22:52:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Axel Rasmussen X-Patchwork-Id: 12227691 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 105AEC43460 for ; Tue, 27 Apr 2021 22:53:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E318361403 for ; Tue, 27 Apr 2021 22:53:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239396AbhD0Wxu (ORCPT ); Tue, 27 Apr 2021 18:53:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239373AbhD0Wxm (ORCPT ); Tue, 27 Apr 2021 18:53:42 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C9F4C06138D for ; Tue, 27 Apr 2021 15:52:58 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id u3-20020a2509430000b02904e7f1a30cffso39410614ybm.8 for ; Tue, 27 Apr 2021 15:52:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=WF9F3v0DTQrGhMQixNFSEHJ4K48zSV5jue/NqesrNqw=; b=E0rIUMeWAgoXEpCSgGFacuFM+ZLoAqWK7X4u5Xdgp+31PQA56XOa/QGxtgDLfgqrvC fr65eCoJ4hgjT9GAidrf06HXEtn9lSMolBwlNj048rZQVvrKH9YfsUU1ugb3m9oRNh8m 4RC9F9WnRcm39mYHDuCLvgGZ2oHStv2UTB/8crxk7MzT8treUGVHoVfJoYLCpDZ8TDZ4 6QwRE+oATYg5O1bFgPNt+nxv6gKrGrEqpxWkvwFrM9CwXBDQfmtfYIz+zGcdSoAI+Ump rf9KbzeE1cMzuP/ldh5eNn8qw967pwi8MhrMX3npQf0JNsMoZbitUZ/LU1YHNQWWcQTj dN2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=WF9F3v0DTQrGhMQixNFSEHJ4K48zSV5jue/NqesrNqw=; b=qR6EZhTDybBdvQ4dP/e4RInkg8nAyc2YbP6S5xIGBG1hjWG+1SUVf1F/Wr+8cNEeDb CB13V241oi8iQ34LvF4sDH9c4jyBmm0M1e42+H9kkn4TgXJW4QauZ+DorGkrQWxIJC1V /7owVYHoaF6fZcDllmFWYg9tSid1o4a/OAVkdMp4EC/FYuOr4aTFr/P5tou3CmhxqQ/w icrkylmoa+TxMZ94BWtEMoO8Y4y7R3zFOmmOVn5sr1JLbFDV33n/1FKNMVp3cB7JSU38 Fow6ir8sIa2CBE5fIJk8HhT1Rm5BsocK108iJvLf+2aFxM1uE6G7uWgasNSgNAVyyox5 F3vA== X-Gm-Message-State: AOAM530DQ4rXK6/n7j8RUia4OBCxWOqxLFf0JVVxRAyD+D93ePOfwjuK t+/jld/h/rT9CA0T2+NhNenuDnKHjgC5hwpyeTu6 X-Google-Smtp-Source: ABdhPJx42SaZU/ckRJAWYZl+sBHBU4dxsBNXvauQrfUBhzIQvOpfUGF4aSkEw6m+v1AIMYKQT6bT7EELye6lYtqQgWNZ X-Received: from ajr0.svl.corp.google.com ([2620:15c:2cd:203:c423:570b:b823:c33e]) (user=axelrasmussen job=sendgmr) by 2002:a25:e803:: with SMTP id k3mr35760658ybd.268.1619563977590; Tue, 27 Apr 2021 15:52:57 -0700 (PDT) Date: Tue, 27 Apr 2021 15:52:39 -0700 In-Reply-To: <20210427225244.4326-1-axelrasmussen@google.com> Message-Id: <20210427225244.4326-6-axelrasmussen@google.com> Mime-Version: 1.0 References: <20210427225244.4326-1-axelrasmussen@google.com> X-Mailer: git-send-email 2.31.1.498.g6c1eba8ee3d-goog Subject: [PATCH v5 05/10] userfaultfd/shmem: advertise shmem minor fault support From: Axel Rasmussen To: Alexander Viro , Andrea Arcangeli , Andrew Morton , Hugh Dickins , Jerome Glisse , Joe Perches , Lokesh Gidra , Mike Kravetz , Mike Rapoport , Peter Xu , Shaohua Li , Shuah Khan , Stephen Rothwell , Wang Qing Cc: linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, Axel Rasmussen , Brian Geffon , "Dr . David Alan Gilbert" , Mina Almasry , Oliver Upton Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Now that the feature is fully implemented (the faulting path hooks exist so userspace is notified, and the ioctl to resolve such faults is available), advertise this as a supported feature. Signed-off-by: Axel Rasmussen Acked-by: Hugh Dickins Acked-by: Peter Xu --- Documentation/admin-guide/mm/userfaultfd.rst | 3 ++- fs/userfaultfd.c | 3 ++- include/uapi/linux/userfaultfd.h | 7 ++++++- 3 files changed, 10 insertions(+), 3 deletions(-) diff --git a/Documentation/admin-guide/mm/userfaultfd.rst b/Documentation/admin-guide/mm/userfaultfd.rst index 3aa38e8b8361..6528036093e1 100644 --- a/Documentation/admin-guide/mm/userfaultfd.rst +++ b/Documentation/admin-guide/mm/userfaultfd.rst @@ -77,7 +77,8 @@ events, except page fault notifications, may be generated: - ``UFFD_FEATURE_MINOR_HUGETLBFS`` indicates that the kernel supports ``UFFDIO_REGISTER_MODE_MINOR`` registration for hugetlbfs virtual memory - areas. + areas. ``UFFD_FEATURE_MINOR_SHMEM`` is the analogous feature indicating + support for shmem virtual memory areas. The userland application should set the feature flags it intends to use when invoking the ``UFFDIO_API`` ioctl, to request that those features be diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 468556fb04a9..9f3b8684cf3c 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1940,7 +1940,8 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, /* report all available features and ioctls to userland */ uffdio_api.features = UFFD_API_FEATURES; #ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR - uffdio_api.features &= ~UFFD_FEATURE_MINOR_HUGETLBFS; + uffdio_api.features &= + ~(UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM); #endif uffdio_api.ioctls = UFFD_API_IOCTLS; ret = -EFAULT; diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h index bafbeb1a2624..159a74e9564f 100644 --- a/include/uapi/linux/userfaultfd.h +++ b/include/uapi/linux/userfaultfd.h @@ -31,7 +31,8 @@ UFFD_FEATURE_MISSING_SHMEM | \ UFFD_FEATURE_SIGBUS | \ UFFD_FEATURE_THREAD_ID | \ - UFFD_FEATURE_MINOR_HUGETLBFS) + UFFD_FEATURE_MINOR_HUGETLBFS | \ + UFFD_FEATURE_MINOR_SHMEM) #define UFFD_API_IOCTLS \ ((__u64)1 << _UFFDIO_REGISTER | \ (__u64)1 << _UFFDIO_UNREGISTER | \ @@ -185,6 +186,9 @@ struct uffdio_api { * UFFD_FEATURE_MINOR_HUGETLBFS indicates that minor faults * can be intercepted (via REGISTER_MODE_MINOR) for * hugetlbfs-backed pages. + * + * UFFD_FEATURE_MINOR_SHMEM indicates the same support as + * UFFD_FEATURE_MINOR_HUGETLBFS, but for shmem-backed pages instead. */ #define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0) #define UFFD_FEATURE_EVENT_FORK (1<<1) @@ -196,6 +200,7 @@ struct uffdio_api { #define UFFD_FEATURE_SIGBUS (1<<7) #define UFFD_FEATURE_THREAD_ID (1<<8) #define UFFD_FEATURE_MINOR_HUGETLBFS (1<<9) +#define UFFD_FEATURE_MINOR_SHMEM (1<<10) __u64 features; __u64 ioctls;