From patchwork Wed Apr 15 03:35:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Liu, Jingqi" X-Patchwork-Id: 1270851 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=intel.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4927T41yjcz9sSX for ; Wed, 15 Apr 2020 13:42:00 +1000 (AEST) Received: from localhost ([::1]:42366 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jOYw2-0004Kh-6Z for incoming@patchwork.ozlabs.org; Tue, 14 Apr 2020 23:41:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48654) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jOYuW-000295-1p for qemu-devel@nongnu.org; Tue, 14 Apr 2020 23:40:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jOYuU-0000kj-G0 for qemu-devel@nongnu.org; Tue, 14 Apr 2020 23:40:23 -0400 Received: from mga01.intel.com ([192.55.52.88]:4323) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jOYuU-0000jA-0X for qemu-devel@nongnu.org; Tue, 14 Apr 2020 23:40:22 -0400 IronPort-SDR: VJhoo/Om8EEMi09m5tPil2QmzCj2Su/N4SrlkJnER8OzsECB3iInjD8slfWWX5KFS+lKUo1AQI t3KUDeD9RtTQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2020 20:40:17 -0700 IronPort-SDR: stj/CEM85xbeawe0j05JhvWneRlBBntwJhlPCiM/DboGrfuPlM92I5bx6LcL1KGpwKZ9rIFJt0 dLTdzhtsSxDQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,385,1580803200"; d="scan'208";a="256729963" Received: from dazhang1-mobile.sh.intel.com ([10.239.48.70]) by orsmga006.jf.intel.com with ESMTP; 14 Apr 2020 20:40:15 -0700 From: Jingqi Liu To: Paolo Bonzini , Richard Henderson , Xiao Guangrong , Dan Williams Subject: [PATCH v2 2/3] docs/nvdimm: add description of alignment requirement of device dax Date: Wed, 15 Apr 2020 11:35:37 +0800 Message-Id: <20200415033538.43329-3-jingqi.liu@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200415033538.43329-1-jingqi.liu@intel.com> References: <20200415033538.43329-1-jingqi.liu@intel.com> X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x [fuzzy] X-Received-From: 192.55.52.88 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jingqi Liu , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" For device dax (e.g., /dev/dax0.0), the NUM of 'align=NUM' option needs to match the alignment requirement of the device dax. It must be larger than or equal to the 'align' of device dax. Signed-off-by: Jingqi Liu --- docs/nvdimm.txt | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt index 362e99109e..3c7b6dab5f 100644 --- a/docs/nvdimm.txt +++ b/docs/nvdimm.txt @@ -132,6 +132,15 @@ address to the page size (getpagesize(2)) by default. However, some types of backends may require an alignment different than the page size. In that case, QEMU v2.12.0 and later provide 'align' option to memory-backend-file to allow users to specify the proper alignment. +For device dax (e.g., /dev/dax0.0), this alignment needs to match the +alignment requirement of the device dax. The NUM of 'align=NUM' option +must be larger than or equal to the 'align' of device dax. +We can use the following command to show the 'align' of device dax. + + ndctl list -X + +In order to get the proper 'align' of device dax, you need to install +the library 'libdaxctl'. For example, device dax require the 2 MB alignment, so we can use following QEMU command line options to use it (/dev/dax0.0) as the