From patchwork Wed Jul 6 08:20:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 12907572 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0698EC433EF for ; Wed, 6 Jul 2022 08:27:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232138AbiGFI1t (ORCPT ); Wed, 6 Jul 2022 04:27:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232426AbiGFI11 (ORCPT ); Wed, 6 Jul 2022 04:27:27 -0400 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 180FF240BF; Wed, 6 Jul 2022 01:26:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657095997; x=1688631997; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=XcUkjLL+YpWw11P834waxgWm/NgeT+vT/ACdu5U5CAo=; b=bXM4SmRunfF2UdZ6n2adSVce6ocOAHH1xRPLAz10BV2oKs9zugqpZkDy 8i33755KPbazt9wepKm6IEY9asDygjbALi4nVDTUKElkJVhrytr9AY+iK DMtg4aMn8kiGYKQ7RxwoeO+ZVSKw/DE6Sjp0yXxFaFrmSlRLnyJ59JWqW cjfUGgcV7pYTkEupEnsOMoikiq642Z/9e8cVFbFRWfd57+w97Id6rkxlE 94y5G41P/YmbhWo6wHoy7WDEtgDB0Kc0o2RORHR3+CCPMpgcTA6faftRQ 9/d2CCGhHdmRTsZuRYjZLmND6Cb8Tax3SjIOkgKFBb0QbNGSwZ/WayQXC g==; X-IronPort-AV: E=McAfee;i="6400,9594,10399"; a="272467402" X-IronPort-AV: E=Sophos;i="5.92,249,1650956400"; d="scan'208";a="272467402" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jul 2022 01:26:34 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,249,1650956400"; d="scan'208";a="567968372" Received: from chaop.bj.intel.com ([10.240.192.101]) by orsmga006.jf.intel.com with ESMTP; 06 Jul 2022 01:26:16 -0700 From: Chao Peng To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org, linux-kselftest@vger.kernel.org Cc: Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , Chao Peng , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , Michael Roth , mhocko@suse.com, Muchun Song Subject: [PATCH v7 14/14] memfd_create.2: Describe MFD_INACCESSIBLE flag Date: Wed, 6 Jul 2022 16:20:16 +0800 Message-Id: <20220706082016.2603916-15-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220706082016.2603916-1-chao.p.peng@linux.intel.com> References: <20220706082016.2603916-1-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Signed-off-by: Chao Peng --- man2/memfd_create.2 | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/man2/memfd_create.2 b/man2/memfd_create.2 index 89e9c4136..2698222ae 100644 --- a/man2/memfd_create.2 +++ b/man2/memfd_create.2 @@ -101,6 +101,19 @@ meaning that no other seals can be set on the file. .\" FIXME Why is the MFD_ALLOW_SEALING behavior not simply the default? .\" Is it worth adding some text explaining this? .TP +.BR MFD_INACCESSIBLE +Disallow userspace access through ordinary MMU accesses via +.BR read (2), +.BR write (2) +and +.BR mmap (2). +The file size cannot be changed once initialized. +This flag cannot coexist with +.B MFD_ALLOW_SEALING +and when this flag is set, the initial set of seals will be +.B F_SEAL_SEAL, +meaning that no other seals can be set on the file. +.TP .BR MFD_HUGETLB " (since Linux 4.14)" .\" commit 749df87bd7bee5a79cef073f5d032ddb2b211de8 The anonymous file will be created in the hugetlbfs filesystem using