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 8D121C77B6E for ; Thu, 13 Apr 2023 17:22:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229829AbjDMRWS (ORCPT ); Thu, 13 Apr 2023 13:22:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50416 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229804AbjDMRWQ (ORCPT ); Thu, 13 Apr 2023 13:22:16 -0400 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5193C8688 for ; Thu, 13 Apr 2023 10:22:14 -0700 (PDT) Received: by mail-pg1-x54a.google.com with SMTP id a187-20020a6390c4000000b0051b4e658d0bso1057971pge.23 for ; Thu, 13 Apr 2023 10:22:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1681406534; x=1683998534; h=cc:to:from:subject:message-id:mime-version:in-reply-to:date:from:to :cc:subject:date:message-id:reply-to; bh=MUWO1kZAYR92KIzOOxoAG6fgcpTDrbsTBnBgIaXB7SI=; b=k9K7/cx14r1rZ44+YUmMJA/zyDFSnSwd4M/yoOo6MK1lBZbqEHHMPLqbgmJy4VHzWr BHtqD7duSRrul042d0Suw2viax09pK0xMVdFhDXpoxoBfhFfIuBKNDsrnzf3PtlFwTe0 xZs14NrJu4rjfC+GuieNJRVga4Qv8eQWhGsY7num3+DbmUoQdqIvovvw7B75AYwZTkKG iKlZHnMH6l41XSupS5sXqcJVcqX0LpFcpp/+2ct//bBU6UJaLCpcjq4ly/wd092FSy5B RAM7fGGTnnv8Bkbvo6qpHrJ0vab0jDHA6Sxzq0hjEQ4MKc/Y3j5NGUn0fKFRnXbWoeyn RO7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681406534; x=1683998534; h=cc:to:from:subject:message-id:mime-version:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=MUWO1kZAYR92KIzOOxoAG6fgcpTDrbsTBnBgIaXB7SI=; b=KVNCQ4A90ajRhwiztlPBxg7/eQS0JnMdgZ7ArJPQDm1dLkYJGj6Fb3OeWbOP/pdLA7 FJgfuHdCTeaBkSM1NvWq7f/oc8DM7U6khh85Ip2MOTWWXhYBq3SeWqEdkW0WonngzALW Ft4qJTxGXE7kakLjVPHZkBJfl5BEvdA1IPhLRguRpWNlfstPCjdhwlJ71HDB05eNUVw5 /eZgrExhZ7Cg1YMbDT+95RaAg+oPDT5kwQVjix5pGXAI2EFDO7ayI0eWNtrCByMd1St7 MS35utYhDXpbZOBgb+OK5rJ2XoCJGw3mhPrmwyctbfuEXiiWR9InpMcrcHNNxQrEVGJ8 eQQg== X-Gm-Message-State: AAQBX9dgp7V57MQG0x0lwq+2XQrxJ0B+2xqa7ZR5bziZPZJqRSMT/SaQ OSn3H4Mgesst9NsxXKgAOqtBhKnKAXSGzYzZ5g== X-Google-Smtp-Source: AKy350buit0TKoFObhZndLsv+Oe7SecvOYrJwebJQwpxXJ4Pb+22Ci4SNV5J0w0/4fgc4zy9sZpOZtI2T9SDAix8Kg== X-Received: from ackerleytng-cloudtop.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:1f5f]) (user=ackerleytng job=sendgmr) by 2002:a17:90b:815:b0:246:a1b2:77fe with SMTP id bk21-20020a17090b081500b00246a1b277femr2564960pjb.3.1681406533842; Thu, 13 Apr 2023 10:22:13 -0700 (PDT) Date: Thu, 13 Apr 2023 17:22:12 +0000 In-Reply-To: <20221202061347.1070246-2-chao.p.peng@linux.intel.com> (message from Chao Peng on Fri, 2 Dec 2022 14:13:39 +0800) Mime-Version: 1.0 Message-ID: Subject: Re: [PATCH v10 1/9] mm: Introduce memfd_restricted system call to create restricted user memory From: Ackerley Tng To: Chao Peng Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org, pbonzini@redhat.com, corbet@lwn.net, seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, arnd@arndb.de, naoya.horiguchi@nec.com, linmiaohe@huawei.com, x86@kernel.org, hpa@zytor.com, hughd@google.com, jlayton@kernel.org, bfields@fieldses.org, akpm@linux-foundation.org, shuah@kernel.org, rppt@kernel.org, steven.price@arm.com, mail@maciej.szmigiero.name, vbabka@suse.cz, vannapurve@google.com, yu.c.zhang@linux.intel.com, chao.p.peng@linux.intel.com, kirill.shutemov@linux.intel.com, 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, qperret@google.com, tabba@google.com, michael.roth@amd.com, mhocko@suse.com, wei.w.wang@intel.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Chao Peng writes: > From: "Kirill A. Shutemov" > Introduce 'memfd_restricted' system call with the ability to create > memory areas that are restricted from userspace access through ordinary > MMU operations (e.g. read/write/mmap). The memory content is expected to > be used through the new in-kernel interface by a third kernel module. > ... > diff --git a/mm/restrictedmem.c b/mm/restrictedmem.c > new file mode 100644 > index 000000000000..56953c204e5c > --- /dev/null > +++ b/mm/restrictedmem.c > @@ -0,0 +1,318 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#include "linux/sbitmap.h" > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct restrictedmem_data { > + struct mutex lock; > + struct file *memfd; Can this be renamed to file, or lower_file (as in stacking filesystems)? It's a little confusing because this pointer doesn't actually refer to an fd. 'memfd' is already used by udmabuf to refer to an actual fd [1], which makes this a little misleading. [1] https://elixir.bootlin.com/linux/v6.2.10/source/tools/testing/selftests/drivers/dma-buf/udmabuf.c#L63 > + struct list_head notifiers; > +}; > + > ...