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 X-Spam-Level: X-Spam-Status: No, score=0.1 required=3.0 tests=DATE_IN_FUTURE_03_06, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 394BAC433F4 for ; Fri, 31 Aug 2018 08:00:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D53002083A for ; Fri, 31 Aug 2018 08:00:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D53002083A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727480AbeHaMHD (ORCPT ); Fri, 31 Aug 2018 08:07:03 -0400 Received: from mga05.intel.com ([192.55.52.43]:63090 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727233AbeHaMHD (ORCPT ); Fri, 31 Aug 2018 08:07:03 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Aug 2018 01:00:50 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,309,1531810800"; d="scan'208";a="84932414" Received: from linux.intel.com ([10.54.29.200]) by fmsmga004.fm.intel.com with ESMTP; 31 Aug 2018 01:00:44 -0700 Received: from tiger-server (unknown [10.239.48.163]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by linux.intel.com (Postfix) with ESMTPS id 68AA4580224; Fri, 31 Aug 2018 01:00:42 -0700 (PDT) Date: Sat, 1 Sep 2018 00:39:42 +0800 From: Yi Zhang To: Dave Hansen Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, pbonzini@redhat.com, dan.j.williams@intel.com, dave.jiang@intel.com, yu.c.zhang@intel.com, pagupta@redhat.com, david@redhat.com, jack@suse.cz, hch@lst.de, linux-mm@kvack.org, rkrcmar@redhat.com, jglisse@redhat.com, yi.z.zhang@intel.com Subject: Re: [PATCH V4 4/4] kvm: add a check if pfn is from NVDIMM pmem. Message-ID: <20180831163941.GA1220@tiger-server> Mail-Followup-To: Dave Hansen , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, pbonzini@redhat.com, dan.j.williams@intel.com, dave.jiang@intel.com, yu.c.zhang@intel.com, pagupta@redhat.com, david@redhat.com, jack@suse.cz, hch@lst.de, linux-mm@kvack.org, rkrcmar@redhat.com, jglisse@redhat.com, yi.z.zhang@intel.com References: <4192066a-79f3-2b3e-386f-c4ec9b6dd8fd@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <4192066a-79f3-2b3e-386f-c4ec9b6dd8fd@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-08-30 at 12:07:11 -0700, Dave Hansen wrote: > On 08/22/2018 03:58 AM, Zhang Yi wrote: > > bool kvm_is_reserved_pfn(kvm_pfn_t pfn) > > { > > - if (pfn_valid(pfn)) > > - return PageReserved(pfn_to_page(pfn)); > > + struct page *page; > > + > > + if (pfn_valid(pfn)) { > > + page = pfn_to_page(pfn); > > + return PageReserved(page) && !is_dax_page(page); > > + } > > This is in desperate need of commenting about what it is doing and why. > > The changelog alone doesn't cut it. Thanks, Dave, Will add some comments