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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD376C25B0C for ; Wed, 10 Aug 2022 09:44:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6CB8F8E0002; Wed, 10 Aug 2022 05:44:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6A1F68E0001; Wed, 10 Aug 2022 05:44:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5438E8E0002; Wed, 10 Aug 2022 05:44:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 4691B8E0001 for ; Wed, 10 Aug 2022 05:44:00 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id EE1BD1A0EA8 for ; Wed, 10 Aug 2022 09:43:59 +0000 (UTC) X-FDA: 79783196598.03.59B19A6 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by imf14.hostedemail.com (Postfix) with ESMTP id 227A91000A6 for ; Wed, 10 Aug 2022 09:43:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1660124639; x=1691660639; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=+g1tHa8U1L0ibLkauTiBh/SeADRVoqwRkL+l6I4l0TE=; b=nMdUU/5mBULqUV+QC30CS2kZLI/3KeDUOxflsYyjP6x/UVe3qDqT/gTD yQBK0W83mRxbKbrv5W1J8AlfK0OcmoplwSq+c0+UWiNTGeMsYeHWQ6TWe /Wu4CmtFG7qIghGtUpZ9O+FfFYAQ/0J4FXLlDjIZIoUV7mwc455Rz6rIH 3AWvwEdw1+uGL4+X1O9/HxxHEkWeqsQ/Zdqo56lFDGywd/CW72eyI2zuA a6An4Y5CjhremG6spRof0uvQBhaC6MuazUswo771IevGQbDEY8d8dWUm9 YyBuVruZui1HxsE12Ks1BV6nBcwmibr9nLjeSN/CnP2aBFghuJtSSTyJC A==; X-IronPort-AV: E=McAfee;i="6400,9594,10434"; a="291043813" X-IronPort-AV: E=Sophos;i="5.93,227,1654585200"; d="scan'208";a="291043813" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Aug 2022 02:43:57 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,227,1654585200"; d="scan'208";a="601757538" Received: from chaop.bj.intel.com (HELO localhost) ([10.240.193.75]) by orsmga007.jf.intel.com with ESMTP; 10 Aug 2022 02:43:45 -0700 Date: Wed, 10 Aug 2022 17:38:59 +0800 From: Chao Peng To: Paolo Bonzini Cc: David Hildenbrand , 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, 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 , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , Michael Roth , mhocko@suse.com, Muchun Song Subject: Re: [PATCH v7 01/14] mm: Add F_SEAL_AUTO_ALLOCATE seal to memfd Message-ID: <20220810093859.GF862421@chaop.bj.intel.com> Reply-To: Chao Peng References: <20220706082016.2603916-1-chao.p.peng@linux.intel.com> <20220706082016.2603916-2-chao.p.peng@linux.intel.com> <472207cf-ff71-563b-7b66-0c7bea9ea8ad@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <472207cf-ff71-563b-7b66-0c7bea9ea8ad@redhat.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660124639; a=rsa-sha256; cv=none; b=x1urj3aCiLHaxnKjTfFhN4MOFqpzCs2VWMPaA5n5RDcTj4mkmWrMtIV/NeQy5GsWf59KIJ XkcnCall7nR3h1MzXnzSp0ZpIU7i0wPKcOom1HHQCiQRMyWjB3zyKUqC8zU9IxOM5BDLKE kANsV+ztnhWnCcmMvMhSGIi8YHQYQ3c= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b="nMdUU/5m"; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none); spf=none (imf14.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 192.55.52.115) smtp.mailfrom=chao.p.peng@linux.intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660124639; h=from:from:sender:reply-to: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=HHCY8oZDLxTD83WlQ+FK/ZyUKIUMQm5v+c549SW3Y9c=; b=jyH/5FMGHExRRE7fJUA0Dcpfs8bDrFbAvXWvZ9f8k983DbFxTq1JmV7R8GDXNdBFWA17bW UliobOiMYIj/KJSdkx0BLWktL9CWkdtqYz8qyY3Bh6JMYdz8vEODVrVYge8qYXhrr6tcmg JSaAtSuiohhXJCS/Kbv4HCMqxK0R9Ho= X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 227A91000A6 Authentication-Results: imf14.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b="nMdUU/5m"; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none); spf=none (imf14.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 192.55.52.115) smtp.mailfrom=chao.p.peng@linux.intel.com X-Rspam-User: X-Stat-Signature: ecwcf1aaw4r1s69refccgj3yt9fa9m4i X-HE-Tag: 1660124638-779628 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Aug 05, 2022 at 07:55:38PM +0200, Paolo Bonzini wrote: > On 7/21/22 11:44, David Hildenbrand wrote: > > > > Also, I*think* you can place pages via userfaultfd into shmem. Not > > sure if that would count "auto alloc", but it would certainly bypass > > fallocate(). > > Yeah, userfaultfd_register would probably have to forbid this for > F_SEAL_AUTO_ALLOCATE vmas. Maybe the memfile_node can be reused for this, > adding a new MEMFILE_F_NO_AUTO_ALLOCATE flags? Then userfault_register > would do something like memfile_node_get_flags(vma->vm_file) and check the > result. Then we need change userfault_register uAPI for a new property flag. Userspace should still the decision-maker for this flag. > > This means moving this patch later, after "mm: Introduce memfile_notifier". Yes, it makes sense now. Chao > > Thanks, > > Paolo