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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 E192EC43381 for ; Tue, 26 Mar 2019 12:37:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A371A2075D for ; Tue, 26 Mar 2019 12:37:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731351AbfCZMhk convert rfc822-to-8bit (ORCPT ); Tue, 26 Mar 2019 08:37:40 -0400 Received: from mga11.intel.com ([192.55.52.93]:29032 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726111AbfCZMhk (ORCPT ); Tue, 26 Mar 2019 08:37:40 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Mar 2019 05:37:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,271,1549958400"; d="scan'208";a="144008706" Received: from fmsmsx107.amr.corp.intel.com ([10.18.124.205]) by FMSMGA003.fm.intel.com with ESMTP; 26 Mar 2019 05:37:40 -0700 Received: from fmsmsx163.amr.corp.intel.com (10.18.125.72) by fmsmsx107.amr.corp.intel.com (10.18.124.205) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 26 Mar 2019 05:37:40 -0700 Received: from shsmsx103.ccr.corp.intel.com (10.239.4.69) by fmsmsx163.amr.corp.intel.com (10.18.125.72) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 26 Mar 2019 05:37:39 -0700 Received: from shsmsx104.ccr.corp.intel.com ([169.254.5.74]) by SHSMSX103.ccr.corp.intel.com ([169.254.4.134]) with mapi id 14.03.0415.000; Tue, 26 Mar 2019 20:37:37 +0800 From: "Liu, Yi L" To: Alex Williamson CC: "kwankhede@nvidia.com" , "Tian, Kevin" , "baolu.lu@linux.intel.com" , "Sun, Yi Y" , "joro@8bytes.org" , "jean-philippe.brucker@arm.com" , "peterx@redhat.com" , "linux-kernel@vger.kernel.org" Subject: RE: [RFC v2 1/2] vfio/pci: export common symbols in vfio-pci Thread-Topic: [RFC v2 1/2] vfio/pci: export common symbols in vfio-pci Thread-Index: AQHU3n+esUAe9/isNUydLtMfe2TJLqYUYO3wgAAAWwCAAvOvgIAE1eUAgAGyJzA= Date: Tue, 26 Mar 2019 12:37:37 +0000 Message-ID: References: <1552378703-11202-1-git-send-email-yi.l.liu@intel.com> <1552378703-11202-2-git-send-email-yi.l.liu@intel.com> <20190319121416.27495651@x1.home> <20190320132202.6279a190@x1.home> <20190325121720.53935577@x1.home> In-Reply-To: <20190325121720.53935577@x1.home> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.0.400.15 dlp-reaction: no-action x-ctpclassification: CTP_NT x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiNWUzM2VmYTgtZTVkYi00NDU1LTk0ODAtODkzMmVmZDM3ZjVmIiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjEwLjE4MDQuNDkiLCJUcnVzdGVkTGFiZWxIYXNoIjoiVGZxeDljUE1rQ2FqRENhWURVRTVzV204YUF5Y1pmWGNReFBtN2pCRmgzY2dGWFI0dFVhRFZPbWlyNlJQK1hMcSJ9 x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > From: Alex Williamson [mailto:alex.williamson@redhat.com] > Sent: Tuesday, March 26, 2019 2:17 AM > To: Liu, Yi L > Subject: Re: [RFC v2 1/2] vfio/pci: export common symbols in vfio-pci > > On Sat, 23 Mar 2019 11:06:44 +0000 > "Liu, Yi L" wrote: > > Hi Alex, [...] > > > > I tried to get a common file which includes the definitions of the module > > options and the common interfaces and get it linked separately with each > > module. It works well when linked separately by config the > > CONFIG_VFIO_PCI=m and CONFIG_VFIO_PCI_MDEV=m in kernel > > configuration file. CONFIG_VFIO_PCI_MDEV is a new Kconfig macro > > for the mdev wrapped version driver. However, if building the vfio-pci > > and the mdev wrapped version into kernel image (config the > > CONFIG_VFIO_PCI=y and CONFIG_VFIO_PCI_MDEV=y), then the symbols > > defined in the common file will be shared thus doesn't allow dissimilar > > user settings. > > > > Per my understanding, I think we expect to allow simultaneous usage of > > the two drivers. So I think the way above doesn't meet our expectation. > > I agree. They should be related in implementation only, from a user > perspective they should be entirely separate. > > > I considered a possible proposal as below. May listen to your opinion > > on it before heading to cook. Also, better idea is welcomed. :-) > > > > - get a common file includes interfaces which are common and have > > input parameters to differentiate the calling from vfio-pci and the > > wrapped version. e.g. vfio_pci_rw(). may call it as vfio_pci_common.c. > > > > - get another common file includes the definitions of the module options, > > and the functions which referred the options. Define all of them as static. > > may call it as common.c > > > > - get vfio_pci.c which includes the module_init/exit interfaces and driver > > registration operations of vfio-pci.ko. This file should include the common.c > > above to have same module options with the mdev wrapped version. > > > > - get vfio_pci_mdev.c which includes the module_init/exit interfaces and > > driver registration operations of vfio-pci-mdev.ko. It should also include > > the common.c above to have same module options with vfio-pci.ko. > > > > - Makefile: > > vfio-pci-y := vfio_pci.o vfio_pci_common.o vfio_pci_intrs.o vfio_pci_rdwr.o > vfio_pci_config.o > > vfio-pci-$(CONFIG_VFIO_PCI_IGD) += vfio_pci_igd.o > > vfio-pci-$(CONFIG_VFIO_PCI_NVLINK2) += vfio_pci_nvlink2.o > > > > vfio-pci-mdev-y := vfio_pci_mdev.o vfio_pci_common.o vfio_pci_intrs.o > vfio_pci_rdwr.o vfio_pci_config.o > > vfio-pci-mdev-$(CONFIG_VFIO_PCI_IGD) += vfio_pci_igd.o > > vfio-pci-mdev-$(CONFIG_VFIO_PCI_NVLINK2) += vfio_pci_nvlink2.o > > > > obj-$(CONFIG_VFIO_PCI) += vfio-pci.o > > obj-$(CONFIG_VFIO_PCI_MDEV) += vfio-pci-mdev.o > > Each module needs it's own module_init/exit and will register its own > struct pci_driver, which gives us separate control of the probe and Agreed. > remove callbacks. I think we want the drivers to have the same module > parameters initially, but we don't necessarily want to require it for > any future options, so we can duplicate the parameter declarations. > Then to support the shared code, I think we can easily push nointxmask, > disable_vga, and disable_idle_d3 into bools on the struct > vfio_pci_device, which would be allocated and set by each module's > probe function before calling the shared probe function. sounds good to me. > vfio_fill_ids() could take a pointer to the array to keep them separate > between modules. Agreed. > I think that just leaves the config permission bits, > vfio_pci_{un}init_perm_bits(). Could we use a simple atomic reference > counter on those to potentially share them so they get initialized by > the first caller and freed by the last user, at least in the case of > both drivers being compiled statically into the kernel? Thanks, Sure, I can add it. The two modules will still share the cap_perms and ecap_perms config bits when built statically in kernel. However, I think such share is reasonable. I'll check if any other similar bits in other files. > Alex Thanks for the suggestions, Alex. Let me prepare another RFC. Regards, Yi Liu