From patchwork Wed Apr 29 08:50:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Liu, Jingqi" X-Patchwork-Id: 1279105 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=2001:470:142::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 [IPv6:2001:470:142::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 49Bss04rWyz9sPF for ; Wed, 29 Apr 2020 18:59:32 +1000 (AEST) Received: from localhost ([::1]:55426 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jTiYz-0006Pl-NK for incoming@patchwork.ozlabs.org; Wed, 29 Apr 2020 04:59:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57800) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jTiVb-0000r9-JN for qemu-devel@nongnu.org; Wed, 29 Apr 2020 04:56:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.90_1) (envelope-from ) id 1jTiV8-0001BP-Pm for qemu-devel@nongnu.org; Wed, 29 Apr 2020 04:55:59 -0400 Received: from mga05.intel.com ([192.55.52.43]:25911) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jTiV8-0000gc-7H for qemu-devel@nongnu.org; Wed, 29 Apr 2020 04:55:30 -0400 IronPort-SDR: 2oMX5TntifhWqVnbEk9VVzVb7Aa5gG8P8WCx66ek340dhL71mbMFI7o36u+4o/LV1msX8XLchp yunIbaSzIONw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2020 01:55:29 -0700 IronPort-SDR: ZFkaqk8cmi/LHsjtNeoKiMdBv9VSor/511H/4OSWoscttJ4kJFRBDMEjSxgIgOfKr4PLoeNdHV YWpATLIDYJ8g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,331,1583222400"; d="scan'208";a="459114644" Received: from dazhang1-mobile.sh.intel.com ([10.239.48.70]) by fmsmga005.fm.intel.com with ESMTP; 29 Apr 2020 01:55:26 -0700 From: Jingqi Liu To: Paolo Bonzini , Richard Henderson , Joao Martins , Xiao Guangrong , Dan Williams Subject: [PATCH v3 2/3] docs/nvdimm: add description of alignment requirement of device dax Date: Wed, 29 Apr 2020 16:50:10 +0800 Message-Id: <20200429085011.63752-3-jingqi.liu@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200429085011.63752-1-jingqi.liu@intel.com> References: <20200429085011.63752-1-jingqi.liu@intel.com> Received-SPF: pass client-ip=192.55.52.43; envelope-from=jingqi.liu@intel.com; helo=mga05.intel.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/04/29 04:55:24 X-ACL-Warn: Detected OS = FreeBSD 9.x or newer [fuzzy] X-Received-From: 192.55.52.43 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. Reviewed-by: Joao Martins Signed-off-by: Jingqi Liu --- docs/nvdimm.txt | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt index 362e99109e..c2c6e441b3 100644 --- a/docs/nvdimm.txt +++ b/docs/nvdimm.txt @@ -132,6 +132,16 @@ 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 one of the following commands to show the 'align' of device dax. + + ndctl list -X + daxctl list -R + +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