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 0AD84C43334 for ; Wed, 13 Jul 2022 07:48:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 403F194010A; Wed, 13 Jul 2022 03:48:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 38B919400E5; Wed, 13 Jul 2022 03:48:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 22C7094010A; Wed, 13 Jul 2022 03:48:29 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 0E7319400E5 for ; Wed, 13 Jul 2022 03:48:29 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id D737680E74 for ; Wed, 13 Jul 2022 07:48:28 +0000 (UTC) X-FDA: 79681299096.10.4120DE1 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by imf14.hostedemail.com (Postfix) with ESMTP id 22E72100068 for ; Wed, 13 Jul 2022 07:48:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657698507; x=1689234507; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=nUfcHt/iaf3oMSfMyzHxGwWsSmqpbvlJ2JFwYR1oe/M=; b=Pd6ADhzUzBmyQUPY+R4bkTtL3E8zf8QF+RXzVV3k2RJew8CLApYRBzlA HLWG5vuQL75boTQwxb6aQ1jbo/lzIGsE+7BxE0+OhMpBrzzVHfVrvp/zF m+rlp3LY1xIr2dtMrBI6eBM/fyNHfRhfX10DlkBH5obu5KpFyYRAOCWGv EhlvlbW27YtFTeTiGipBL6OvEtSw7mE6uj3O5dCyGZdPuF2j4Ll5UcwV7 jldXMdrZoF9hVO9Zx6R6xgYmO4tughwJuk5/gPVG2QL+FNNAz2o7GvDgw P9y2a56ePosGT5YCfviSELu/QWtYDum1bcHpAy5na5bCD+D/1Yv+QEhQM g==; X-IronPort-AV: E=McAfee;i="6400,9594,10406"; a="268177486" X-IronPort-AV: E=Sophos;i="5.92,267,1650956400"; d="scan'208";a="268177486" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jul 2022 00:48:25 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,267,1650956400"; d="scan'208";a="685067167" Received: from chaop.bj.intel.com (HELO localhost) ([10.240.192.101]) by FMSMGA003.fm.intel.com with ESMTP; 13 Jul 2022 00:48:16 -0700 Date: Wed, 13 Jul 2022 15:44:58 +0800 From: Chao Peng To: "Gupta, Pankaj" Cc: 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, 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 , "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: Re: [PATCH v7 04/14] mm/shmem: Support memfile_notifier Message-ID: <20220713074458.GB2831541@chaop.bj.intel.com> Reply-To: Chao Peng References: <20220706082016.2603916-1-chao.p.peng@linux.intel.com> <20220706082016.2603916-5-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657698507; a=rsa-sha256; cv=none; b=Yw99Bt196FydhWjreoZ6GYsqn3r8vavgfOKrwz+ImLKJqe9a7cAmkJ+MrBAR9OY6lnhh7E pca94ZYU9kOPWTvwCsqLpbvRlum3ebfzkqK8q72EvUMunG0YSPvZKFtK8spG9JwkCGlkCt ShGnKHzYxfhCLMsuwEm6gKkx2KUB7sc= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Pd6ADhzU; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf14.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 134.134.136.126) 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=1657698507; 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=GxwqbQIAxvEmTdH8aSGICNDAMAM8SqWY33GGZ6vr0J8=; b=eiyUpAHGOcKDMtNgrwZOZbCHqXN+Egg4urlEmLmlvvdBUFYNvEoNZBOLnQKD6G/TmLO90V e6dqWucwZRYy7u9/Vdix33JW8JUoqAcLgokImrHgNoiD4wb19AfsTAXQLW8Ny85itrOMhj rnrZ/BUYWeXtXu7wDXVqbX6bg8If9nk= Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Pd6ADhzU; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf14.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 134.134.136.126) smtp.mailfrom=chao.p.peng@linux.intel.com X-Rspam-User: X-Stat-Signature: a56t7baydcwzu1j6r88enj9c7inuost7 X-Rspamd-Queue-Id: 22E72100068 X-Rspamd-Server: rspam08 X-HE-Tag: 1657698506-537214 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 Tue, Jul 12, 2022 at 08:02:34PM +0200, Gupta, Pankaj wrote: > On 7/6/2022 10:20 AM, Chao Peng wrote: > > From: "Kirill A. Shutemov" > > > > Implement shmem as a memfile_notifier backing store. Essentially it > > interacts with the memfile_notifier feature flags for userspace > > access/page migration/page reclaiming and implements the necessary > > memfile_backing_store callbacks. > > > > Signed-off-by: Kirill A. Shutemov > > Signed-off-by: Chao Peng > > --- > > include/linux/shmem_fs.h | 2 + > > mm/shmem.c | 109 ++++++++++++++++++++++++++++++++++++++- > > 2 files changed, 110 insertions(+), 1 deletion(-) ... > > +#ifdef CONFIG_MIGRATION > > +static int shmem_migrate_page(struct address_space *mapping, > > + struct page *newpage, struct page *page, > > + enum migrate_mode mode) > > +{ > > + struct inode *inode = mapping->host; > > + struct shmem_inode_info *info = SHMEM_I(inode); > > + > > + if (info->memfile_node.flags & MEMFILE_F_UNMOVABLE) > > + return -EOPNOTSUPP; > > + return migrate_page(mapping, newpage, page, mode); > > Wondering how well page migrate would work for private pages > on shmem memfd based backend? >From high level: - KVM unset MEMFILE_F_UNMOVABLE bit to indicate it capable of migrating a page. - Introduce new 'migrate' callback(s) to memfile_notifier_ops for KVM to register. - The callback is hooked to migrate_page() here. - Once page migration requested, shmem calls into the 'migrate' callback(s) to perform additional steps for encrypted memory (For TDX we will call TDH.MEM.PAGE.RELOCATE). Chao > > > +} > > +#endif > > + > > const struct address_space_operations shmem_aops = { > > .writepage = shmem_writepage, > > .dirty_folio = noop_dirty_folio, > > @@ -3814,7 +3872,7 @@ const struct address_space_operations shmem_aops = { > > .write_end = shmem_write_end, > > #endif > > #ifdef CONFIG_MIGRATION > > - .migratepage = migrate_page, > > + .migratepage = shmem_migrate_page, > > #endif > > .error_remove_page = shmem_error_remove_page, > > }; > > @@ -3931,6 +3989,51 @@ static struct file_system_type shmem_fs_type = { > > .fs_flags = FS_USERNS_MOUNT, > > };