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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 10C31C35669 for ; Fri, 21 Feb 2020 20:21:40 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id DC8BE207FD for ; Fri, 21 Feb 2020 20:21:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC8BE207FD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35896 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j5Enr-0000uv-5F for qemu-devel@archiver.kernel.org; Fri, 21 Feb 2020 15:21:39 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:51030) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j5Emo-0008Pg-E3 for qemu-devel@nongnu.org; Fri, 21 Feb 2020 15:20:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j5Emn-0006hM-HG for qemu-devel@nongnu.org; Fri, 21 Feb 2020 15:20:34 -0500 Received: from mga18.intel.com ([134.134.136.126]:50348) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j5Emn-0006fd-7s; Fri, 21 Feb 2020 15:20:33 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Feb 2020 12:20:31 -0800 X-IronPort-AV: E=Sophos;i="5.70,469,1574150400"; d="scan'208";a="229957191" Received: from ajakowsk-mobl1.amr.corp.intel.com (HELO localhost.localdomain) ([10.78.27.169]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 21 Feb 2020 12:20:30 -0800 Subject: Re: [PATCH v1] block/nvme: introduce PMR support from NVMe 1.4 spec To: Stefan Hajnoczi References: <20200218224811.30050-1-andrzej.jakowski@linux.intel.com> <20200221134555.GK1484511@stefanha-x1.localdomain> From: Andrzej Jakowski Message-ID: Date: Fri, 21 Feb 2020 13:20:30 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 134.134.136.126 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: Kevin Wolf , Haozhong Zhang , qemu block , qemu-devel , Max Reitz , Keith Busch , Zhang Yi , Junyan He , "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2/21/20 12:32 PM, Stefan Hajnoczi wrote: > Hi Andrzej, > After having looked at the PMRWBM part of the spec, I think that the > Bit 1 mode should be implemented for slightly better performance. Bit > 0 mode is not well-suited to virtualization for the reasons I > mentioned in the previous email. > > The spec describes Bit 1 mode as "The completion of a read to the > PMRSTS register shall ensure that all prior writes to the Persistent > Memory Region have completed and are persistent". > > Stefan Make sense -- will incorporate that feedback in second version of patch.