From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 90219A0487 for ; Wed, 3 Jul 2019 11:00:56 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 682A11B949; Wed, 3 Jul 2019 11:00:56 +0200 (CEST) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id C1C441E25 for ; Wed, 3 Jul 2019 11:00:54 +0200 (CEST) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Jul 2019 02:00:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,446,1557212400"; d="scan'208";a="190962599" Received: from npg-dpdk-virtio-tbie-2.sh.intel.com (HELO ___) ([10.67.104.151]) by fmsmga002.fm.intel.com with ESMTP; 03 Jul 2019 02:00:52 -0700 Date: Wed, 3 Jul 2019 16:59:29 +0800 From: Tiwei Bie To: David Marchand Cc: dev , "Burakov, Anatoly" Message-ID: <20190703085929.GA30592@___> References: <20190703054508.22824-1-tiwei.bie@intel.com> <20190703073314.GA18868@___> <20190703075657.GA20458@___> <20190703081550.GA25721@___> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Subject: Re: [dpdk-dev] [RFC PATCH] bus/pci: avoid depending on private value in kernel source 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 Wed, Jul 03, 2019 at 10:26:39AM +0200, David Marchand wrote: > On Wed, Jul 3, 2019 at 10:17 AM Tiwei Bie wrote: > > On Wed, Jul 03, 2019 at 10:01:44AM +0200, David Marchand wrote: > > On Wed, Jul 3, 2019 at 9:58 AM Tiwei Bie wrote: > > > > On Wed, Jul 03, 2019 at 09:36:26AM +0200, David Marchand wrote: > > > On Wed, Jul 3, 2019 at 9:35 AM Tiwei Bie > wrote: > > > > > > Hi David, > > > > > > On Wed, Jul 03, 2019 at 09:02:59AM +0200, David Marchand wrote: > > > > Hello, > > > > > > > > On Wed, Jul 3, 2019 at 7:47 AM Tiwei Bie > > > wrote: > > > > > > > > The value 40 used in VFIO_GET_REGION_ADDR() is a private > value > > > > (VFIO_PCI_OFFSET_SHIFT) defined in Linux kernel source > [1]. It > > > > is not part of VFIO API, and we should not depend on it. > > > > > > > > [1] https://github.com/torvalds/linux/blob/6fbc7275c7a9/ > drivers > > /vfio/ > > > pci/ > > > > vfio_pci_private.h#L19 > > > > > > > > > > > > > > > > I did not follow linux kernel changes, is there something > that > > would > > > change > > > > this offset? > > > > It looks like a cleanup (did not look into the details yet), > do we > > need > > > this > > > > now? > > > > > > In VFIO/mdev [1], the offset can be something different. It > depends > > > on the parent device. It's not just a cleanup. It's a > preparation > > > for the mdev support in DPDK. > > > > > > [1] https://github.com/torvalds/linux/blob/master/Documentation > / > > > vfio-mediated-device.txt > > > > > > > > > > > > Ok, thanks. > > > So we can wait for mdev to be ready before working on this. > > > > What do you mean by "mdev to be ready"? RFC ready? I don't see > > anything blocking the discussion on this now. > > > > PS. I already sent a RFC series of the mdev support in DPDK > > to the mailing list 3 month ago. > > > > > > If you need it and the mdev support has been posted already, why not send > a n+1 > > patchset with this patch in it? > > > > This patch alone looked odd to me. > > That series was using the old API which assumes the shift > is 40 which may not work in some cases. And this patch is > to fix the API. I think this patch is actually trying to > fix a relatively independent issue -- i.e. switching to using > the proper VFIO API to get the region offsets instead of > depending on kernel code's internal value. > > > > Fix, then there is something broken ? I should use "fix" (with "") actually :) > You said this is for mdev support which is not currently part of the features > supported by DPDK. > > > This patch breaks the ABI by extending rte_pci_device. > You must rework it to avoid this break. I didn't expect it to be merged in this release. I just want to draw other's attention on this and kick off the discussion (it would be great if you would like to share your thoughts on this). If there is a way to avoid extending rte_pci_device, it would be definitely great. But if we have to break it, then we would want to send out the announce as early as possible. Thanks, Tiwei > > > -- > David Marchand