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 D837FC73C53 for ; Tue, 9 Jul 2019 15:06:21 +0000 (UTC) Received: from dpdk.org (dpdk.org [92.243.14.124]) by mail.kernel.org (Postfix) with ESMTP id 9CFDF214AF for ; Tue, 9 Jul 2019 15:06:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9CFDF214AF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=dev-bounces@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id E040F4C8D; Tue, 9 Jul 2019 17:06:20 +0200 (CEST) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by dpdk.org (Postfix) with ESMTP id 1D902322C for ; Tue, 9 Jul 2019 17:06:19 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Jul 2019 08:06:19 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,470,1557212400"; d="scan'208";a="165787354" Received: from aburakov-mobl1.ger.corp.intel.com (HELO [10.237.220.82]) ([10.237.220.82]) by fmsmga008.fm.intel.com with ESMTP; 09 Jul 2019 08:06:17 -0700 To: Thomas Monjalon , Jerin Jacob Kollanukkaran , David Marchand Cc: dev , Ben Walker References: <20190708142450.51597-1-jerinj@marvell.com> <553b3a91-7458-98d0-9df6-5b53010d326f@intel.com> <2073381.Trv6OtLvPF@xps> From: "Burakov, Anatoly" Message-ID: <5fa3c363-d942-33d8-4baf-3d91653bbdf9@intel.com> Date: Tue, 9 Jul 2019 16:06:17 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <2073381.Trv6OtLvPF@xps> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [EXT] Re: [PATCH] bus/pci: fix IOVA as VA mode selection X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 09-Jul-19 4:04 PM, Thomas Monjalon wrote: > 09/07/2019 16:37, Burakov, Anatoly: >> My view would be to always run in IOVA as VA by default and only falling >> back to IOVA as PA if there is a need to do that. Yet, it seems that >> whenever i try to bring this up, the response (not necessarily from you, >> so this is not directed at you specifically) seems to be that because of >> hotplug, we have to start in the "safest" (from device support point of >> view) mode - that is, in IOVA as PA. Seeing how, as you claim, some >> devices require IOVA as VA, then IOVA as PA is no longer the "safe" >> default that all devices will support. Perhaps we can use this >> opportunity to finally make IOVA as VA the default :) > > That's a good point Anatoly. We need to decide what is the safest default. > > About the capabilities flags, please let's agree that we want > to express 3 cases, so we need 2 flags. We do agree on this. > About the preference of a mode for a device, if a mode is really > bad for a device, I suggest to not advertise it in capabilities. Yes, agree with that as well. > > In order to take a better decision, we need a summary of the > decision algorithm per layer, involving kernel driver capabilities > and memory capabilities. > This needs to be documented very well, as this seems to be a source of great confusion for us all. If all was spelled out in the docs, we wouldn't need this long discussion to figure out that we actually agree :D -- Thanks, Anatoly