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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5D79C433EF for ; Mon, 22 Nov 2021 13:31:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234198AbhKVNey (ORCPT ); Mon, 22 Nov 2021 08:34:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231605AbhKVNey (ORCPT ); Mon, 22 Nov 2021 08:34:54 -0500 Received: from mail-qk1-x730.google.com (mail-qk1-x730.google.com [IPv6:2607:f8b0:4864:20::730]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE4ACC061574 for ; Mon, 22 Nov 2021 05:31:47 -0800 (PST) Received: by mail-qk1-x730.google.com with SMTP id 132so18035114qkj.11 for ; Mon, 22 Nov 2021 05:31:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=u7JEhlzeqWEWi1WfdsbI31hG4XTiKs7YjTVY93B2ee4=; b=CRLeFVlaDHYADj0c4pdgyA6WVjM0CriKWH34VQ3Zgnf0WtTraYkd/cgjTCbMDOczww NdXiD8njOfcPQpNHpYRgBzhYd2yhCkVtjUBQDrAQcLu+SgaPJ18JLMcHZiSnAkVeknnd 0r6V6MGiqUoTitEC42jbkgtqGFrBYYzJPumsEkVo7XS5sE6Xgi92bWwMj7cA04T9KZgG KBEMYlzIWnHu0BDIdQb3DAJr0IAt/qNWxoYSuFBMXOWkuMB4UlcMl9O5g8H1aCzjXOTg YIexlAtl5QrrWHsZHnXp+oDhqqchuEu2x1mCbFWEHmpRnxygBJW2KKryq/0Wb2YGQp6B zPUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=u7JEhlzeqWEWi1WfdsbI31hG4XTiKs7YjTVY93B2ee4=; b=LG081JmXR2MkrbDrMwc7CGKT2KY7ZR8yL110DixxVSFxe6ArsBeTbDaMlswS4LcVHz ny9rI8pXLfJCWnw18XIh444gbleJG2QcjzQ9PXu/qXNuVx2G2V9N6WihhGXJgp0/28Uj vxddojEr7+RbdJVciK7a9Vfg3mNO3h9ReWaXHKFxRX1nfJhmba0s2A6o4PUQ71J/XFtW CbiPbRxMcUvipq1fuX1KwQzQ7WEZx3f7QBmrZCpal8UKqpPH9n8VAqxNIWMGCEymYGAK NuPcjYLjgmrEsKxmSFfjMyUrCq+Ky2a6KYjga2wlCpuXl+Z7oKClSTfsLH0nPCGTEj58 xmkw== X-Gm-Message-State: AOAM531inkquW1li1xSH2LgY0MJdYqFzgJ6cwRAanGfzUFck/HvRx7Vx xieB5X3BPNK1vWICmHazYWw+HKy+lvXxRg== X-Google-Smtp-Source: ABdhPJyVecFgN4ENVdXtmS+AeA6UBpyD+QSrsm4bekxw4Uozjfi2oAytM0ALDEqjOc3nqbmPpEzZDw== X-Received: by 2002:a05:620a:c84:: with SMTP id q4mr47040794qki.176.1637587906879; Mon, 22 Nov 2021 05:31:46 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-162-113-129.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.113.129]) by smtp.gmail.com with ESMTPSA id n19sm4455570qta.78.2021.11.22.05.31.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Nov 2021 05:31:46 -0800 (PST) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1mp9Q9-00DrvP-FD; Mon, 22 Nov 2021 09:31:45 -0400 Date: Mon, 22 Nov 2021 09:31:45 -0400 From: Jason Gunthorpe To: David Hildenbrand Cc: Chao Peng , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, qemu-devel@nongnu.org, 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 , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, john.ji@intel.com, susie.li@intel.com, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com Subject: Re: [RFC v2 PATCH 01/13] mm/shmem: Introduce F_SEAL_GUEST Message-ID: <20211122133145.GQ876299@ziepe.ca> References: <20211119134739.20218-1-chao.p.peng@linux.intel.com> <20211119134739.20218-2-chao.p.peng@linux.intel.com> <20211119151943.GH876299@ziepe.ca> <20211119160023.GI876299@ziepe.ca> <4efdccac-245f-eb1f-5b7f-c1044ff0103d@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4efdccac-245f-eb1f-5b7f-c1044ff0103d@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Nov 22, 2021 at 10:26:12AM +0100, David Hildenbrand wrote: > I do wonder if we want to support sharing such memfds between processes > in all cases ... we most certainly don't want to be able to share > encrypted memory between VMs (I heard that the kernel has to forbid > that). It would make sense in the use case you describe, though. If there is a F_SEAL_XX that blocks every kind of new access, who cares if userspace passes the FD around or not? Jason