From mboxrd@z Thu Jan 1 00:00:00 1970 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EDA79C433EF for ; Tue, 8 Feb 2022 09:22:24 +0000 (UTC) Received: from localhost ([::1]:34452 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nHMhb-000070-Uk for qemu-devel@archiver.kernel.org; Tue, 08 Feb 2022 04:22:23 -0500 Received: from eggs.gnu.org ([209.51.188.92]:43420) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nHMC6-0006mD-Sj for qemu-devel@nongnu.org; Tue, 08 Feb 2022 03:49:57 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:51772) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nHMC3-0006IS-5c for qemu-devel@nongnu.org; Tue, 08 Feb 2022 03:49:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644310184; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=67PxmAL3Xd8LpaVSVss2M9MADvWamDZ50hstBrm0qA0=; b=hBJAKnJsVjqFtw1SgP/A4zPzzzRYRqnq5uy0VkcI0miT1jkkAej5NBBaHhYP/oG35Ip42f Bk74PGQ9vBXhnHyAMSltsBAkDkK7eYZDZP1w1FbQJN6KEnVUJ84wz3PML7/i45SnoWzgrI nV7LXV/3hLnCUDdINr5jYeLpt3OJ3QE= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-650-asQtM6lXOjKKLs9oUq_nWQ-1; Tue, 08 Feb 2022 03:49:41 -0500 X-MC-Unique: asQtM6lXOjKKLs9oUq_nWQ-1 Received: by mail-wr1-f72.google.com with SMTP id b8-20020adfc748000000b001e333edbe40so836453wrh.6 for ; Tue, 08 Feb 2022 00:49:41 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent :content-language:to:cc:references:from:organization:subject :in-reply-to:content-transfer-encoding; bh=67PxmAL3Xd8LpaVSVss2M9MADvWamDZ50hstBrm0qA0=; b=dH/pDhi0y9aLcJBoOa+zzseAkr65UxiLP8WWUOZC4f7AL1jzRhIcdirvP8En8JWBaS ixJyWOmTRuq84fy+2C4g+ZdSCYaKUEVtHVDxwuJCoPqyEGKmh2IfgKPffw1F6YMtT8qt +++4GETQ1/atEoOzbyBeOdA+ih/JKyMlSPPIA/RSdkxHH2KDs4wKrD2ei1gljpBdlMqV 7KMi/0ogi9wLrOFJ31swyzyY0DawJCobSwhJmPygv3juR8bo1MBxB5UjQZjYLJsVmG8M 5Jv1tsrzQkKeo0MYUXp/peiXUztZFDmnRqsF7G/c3QSkyrcyEaC/WlRQO3CUBWKlXcBT Agjw== X-Gm-Message-State: AOAM5323V6dVG+/fVhpQDUiSCL9NpPxqL9resdwj7nFu6JGuizDKaWNN VnFa1SbI9VRpSMXh1Cy7iDYwp40lJWrqNcILVcrpBurhhPsR4y47ePT3uq/wJuFqYGkEQK9RsU/ ylfcfCl6WCDTF2Yc= X-Received: by 2002:a7b:cd10:: with SMTP id f16mr168368wmj.180.1644310180710; Tue, 08 Feb 2022 00:49:40 -0800 (PST) X-Google-Smtp-Source: ABdhPJxHPvqe9Mcgm6+Q7EEAETSuMiKnrZQ8yFi6vJk5xylaclj7xAKcrNR6NQiWp2HFxsqZydBSFg== X-Received: by 2002:a7b:cd10:: with SMTP id f16mr168333wmj.180.1644310180425; Tue, 08 Feb 2022 00:49:40 -0800 (PST) Received: from ?IPV6:2003:cb:c712:a800:a1a0:a823:5301:d1af? (p200300cbc712a800a1a0a8235301d1af.dip0.t-ipconnect.de. [2003:cb:c712:a800:a1a0:a823:5301:d1af]) by smtp.gmail.com with ESMTPSA id b16sm1728277wrj.26.2022.02.08.00.49.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Feb 2022 00:49:37 -0800 (PST) Message-ID: <07aae6e7-4042-1c5c-a482-6ad3a34a3b07@redhat.com> Date: Tue, 8 Feb 2022 09:49:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 To: Vlastimil Babka , Chao Peng , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, qemu-devel@nongnu.org References: <20220118132121.31388-1-chao.p.peng@linux.intel.com> <20220118132121.31388-3-chao.p.peng@linux.intel.com> <25166513-3074-f3b9-12cc-420ba74f153e@suse.cz> From: David Hildenbrand Organization: Red Hat Subject: Re: [PATCH v4 02/12] mm/memfd: Introduce MFD_INACCESSIBLE flag In-Reply-To: <25166513-3074-f3b9-12cc-420ba74f153e@suse.cz> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Wanpeng Li , luto@kernel.org, "J . Bruce Fields" , dave.hansen@intel.com, "H . Peter Anvin" , ak@linux.intel.com, Jonathan Corbet , Joerg Roedel , x86@kernel.org, Hugh Dickins , Mike Rapoport , Ingo Molnar , Borislav Petkov , jun.nakajima@intel.com, Thomas Gleixner , Vitaly Kuznetsov , Jim Mattson , Sean Christopherson , Jeff Layton , Yu Zhang , Paolo Bonzini , Andrew Morton , "Kirill A . Shutemov" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 07.02.22 19:51, Vlastimil Babka wrote: > On 1/18/22 14:21, Chao Peng wrote: >> Introduce a new memfd_create() flag indicating the content of the >> created memfd is inaccessible from userspace. It does this by force >> setting F_SEAL_INACCESSIBLE seal when the file is created. It also set >> F_SEAL_SEAL to prevent future sealing, which means, it can not coexist >> with MFD_ALLOW_SEALING. >> >> The pages backed by such memfd will be used as guest private memory in >> confidential computing environments such as Intel TDX/AMD SEV. Since >> page migration/swapping is not yet supported for such usages so these >> pages are currently marked as UNMOVABLE and UNEVICTABLE which makes >> them behave like long-term pinned pages. > > Shouldn't the amount of such memory allocations be restricted? E.g. similar > to secretmem_mmap() doing mlock_future_check(). I've raised this already in the past and Kirill wanted to look into it [1]. We'll most certainly need a way to limit/control the amount of unswappable + unmovable ("worse than mlock" memory) a user/process can consume via this mechanism. [1] https://lkml.kernel.org/r/20211122135933.arjxpl7wyskkwvwv@box.shutemov.name -- Thanks, David / dhildenb