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 686FBC433EF for ; Wed, 13 Jul 2022 23:52:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D5516940163; Wed, 13 Jul 2022 19:52:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D05F8940134; Wed, 13 Jul 2022 19:52:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BCC60940163; Wed, 13 Jul 2022 19:52:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id AE384940134 for ; Wed, 13 Jul 2022 19:52:33 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 7BE2820646 for ; Wed, 13 Jul 2022 23:52:33 +0000 (UTC) X-FDA: 79683728586.18.FA2AEEA Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by imf21.hostedemail.com (Postfix) with ESMTP id 6CF4A1C007A for ; Wed, 13 Jul 2022 23:52:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657756352; x=1689292352; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=d4b95Nutiv+fVkeoTmmbeGdels6G19ALZ7QCpFCTTwc=; b=makj51lrEwaqsW/cUT5VKSkG43/cgJnWbVX/0l7MSikEWPgO+3RwbHTq F5ccYlt5z06dgRi5lFpHKYqWiZqxrGt0Sc8Qn1riz6CyK0LWXc573WTRb jSHALGjFhIAOtDBLOYwZVu1N4fpsijw5a7L48+8eIlTaTtw1zKwAN+SQn dKmRkIxiBw3zbQW1DBkroH2W46YaDtMB/On6TZqir33mBoPi+H2q+i++M eC42B4cuot+HAc3uHDbdCr3VTBSKiF59LPycomzuF1DM/rHdz7QhUcu6V uY9V7pkEZAdmZTxncZYWfyKJVBZpHnmPuPiQoJTy9OCZCIbLUzmUAT7SO A==; X-IronPort-AV: E=McAfee;i="6400,9594,10407"; a="349342774" X-IronPort-AV: E=Sophos;i="5.92,269,1650956400"; d="scan'208";a="349342774" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jul 2022 16:52:30 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,269,1650956400"; d="scan'208";a="593176855" Received: from chaop.bj.intel.com (HELO localhost) ([10.240.192.101]) by orsmga007.jf.intel.com with ESMTP; 13 Jul 2022 16:52:20 -0700 Date: Thu, 14 Jul 2022 07:49:03 +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: <20220713234903.GA2881285@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> <20220713074458.GB2831541@chaop.bj.intel.com> <74097857-1908-2ff2-1e54-bf7e658ea6c6@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <74097857-1908-2ff2-1e54-bf7e658ea6c6@amd.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657756353; a=rsa-sha256; cv=none; b=5wECQpmafFrglcMc3CS7lrCkilah7UBGUj5MbWCOem43GkaYH0tfHCxSTIl0V9qvDSmQuh C7czkWaNuvE7/zJRBFx6+I8NlQ7o1rFD+NiGMH4ZNMdP/5kzicevbhcQHK8fauE3HuhdT7 fiT40RJZyAc3EsEWm4AETuFDnHGfNFg= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=makj51lr; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf21.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 134.134.136.100) 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=1657756353; 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=0cgtXhmiy3DQje0BJmWcpgfvjOLF0Y0+Tm3y5pnBDe0=; b=grgVDO1QkuX3OmTkrkShMruioeyjs3AOkQ3i62IZGB+tTVGdfhoHm7qXliT5Ionk8o4rkO F+KhZgRQHt0+EQ8De5yE88tJX4IM+ClRlVCjTF/4YePCMfLanicvF+704aLQbQhurkZfpQ 6tbrvXBhgrPTki74Km1C4KxrfxMUqH4= Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=makj51lr; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf21.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 134.134.136.100) smtp.mailfrom=chao.p.peng@linux.intel.com X-Rspam-User: X-Stat-Signature: s5a468165tuzkeunxm8bnxjhy6kjgsoz X-Rspamd-Queue-Id: 6CF4A1C007A X-Rspamd-Server: rspam08 X-HE-Tag: 1657756352-983735 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 Wed, Jul 13, 2022 at 12:01:13PM +0200, Gupta, Pankaj wrote: > > > > > +#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). > > Yes, that would require additional (protocol specific) handling for private > pages. Was trying to find where "MEMFILE_F_UNMOVABLE" flag is set currently? It's set with memfile_register_notifier() in patch 13. > > Thanks, > Pankaj