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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52C47C433EF for ; Fri, 7 Jan 2022 06:03:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232837AbiAGGDP (ORCPT ); Fri, 7 Jan 2022 01:03:15 -0500 Received: from out30-42.freemail.mail.aliyun.com ([115.124.30.42]:47255 "EHLO out30-42.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232763AbiAGGDO (ORCPT ); Fri, 7 Jan 2022 01:03:14 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R751e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=yaohongbo@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0V19Yyfg_1641535391; Received: from 30.225.24.141(mailfrom:yaohongbo@linux.alibaba.com fp:SMTPD_---0V19Yyfg_1641535391) by smtp.aliyun-inc.com(127.0.0.1); Fri, 07 Jan 2022 14:03:12 +0800 Message-ID: <24d3294b-2d22-3f68-e280-a833879c69b1@linux.alibaba.com> Date: Fri, 7 Jan 2022 14:03:10 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [RFC PATCH] PCI: Add "pci=reassign_all_bus" boot parameter To: bhelgaas@google.com Cc: zhangliguang@linux.alibaba.com, alikernel-developer@linux.alibaba.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org References: <1640856613-101412-1-git-send-email-yaohongbo@linux.alibaba.com> From: Yao Hongbo In-Reply-To: <1640856613-101412-1-git-send-email-yaohongbo@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hi, Bjorn, Gentel ping! Any comments on this patch? I think this is useful to find whether there is a problem with the PCI enumeration of the bios or the OS. 在 2021/12/30 下午5:30, Yao Hongbo 写道: > PCI bridges may be misconfigured by te system BIOS, and then the OS > scan the bridges that need to be reconfigured. > However, the PCI bus topology configured by the bios may be wrong: > > [ 19.376273] pci 0000:40:00.0: bridge configuration invalid ([bus > 00-00]), reconfiguring > [ 19.384443] pci_bus 0000:47: busn_res: can not insert [bus 47-46] > under [bus 40-46] (conflicts with (null) [bus 40-46]) > > The primary bus number and subordinate bus number written by the bios > were wrong, and the OS continues to add bridges on the wrong bus > topology. > > In order to avoid such problems, a kernel cmdline needs to be > added to support the os to fully configure the pci bus. > > Signed-off-by: Yao Hongbo > --- > Documentation/admin-guide/kernel-parameters.txt | 1 + > drivers/acpi/pci_root.c | 3 +++ > drivers/pci/pci.c | 5 +++++ > include/linux/pci.h | 2 ++ > 4 files changed, 11 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 2fba824..c83a2e5 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -4084,6 +4084,7 @@ > nomio [S390] Do not use MIO instructions. > norid [S390] ignore the RID field and force use of > one PCI domain per PCI function > + reassign_all_bus The OS fully configure the PCI bus. > > pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power > Management. > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c > index ab2f7df..e21ac25 100644 > --- a/drivers/acpi/pci_root.c > +++ b/drivers/acpi/pci_root.c > @@ -592,6 +592,9 @@ static int acpi_pci_root_add(struct acpi_device *device, > is_pcie = strcmp(acpi_device_hid(device), "PNP0A08") == 0; > negotiate_os_control(root, &no_aspm, is_pcie); > > + if (pci_reassign_all_bus) > + pci_add_flags(PCI_REASSIGN_ALL_BUS); > + > /* > * TBD: Need PCI interface for enumeration/configuration of roots. > */ > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 3d2fb39..5746e88 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -142,6 +142,9 @@ bool pci_reset_supported(struct pci_dev *dev) > /* If set, the PCI config space of each device is printed during boot. */ > bool pci_early_dump; > > +/* If set, the pci will reassign resources*/ > +bool pci_reassign_all_bus; > + > bool pci_ats_disabled(void) > { > return pcie_ats_disabled; > @@ -6846,6 +6849,8 @@ static int __init pci_setup(char *str) > pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS); > } else if (!strncmp(str, "disable_acs_redir=", 18)) { > disable_acs_redir_param = str + 18; > + } else if (!strncmp(str, "reassign_all_bus", 16)) { > + pci_reassign_all_bus = true; > } else { > pr_err("PCI: Unknown option `%s'\n", str); > } > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 18a75c8e..ad0e3e9 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -2119,6 +2119,8 @@ int pcim_iomap_regions_request_all(struct pci_dev *pdev, int mask, > extern u8 pci_dfl_cache_line_size; > extern u8 pci_cache_line_size; > > +extern bool pci_reassign_all_bus; > + > /* Architecture-specific versions may override these (weak) */ > void pcibios_disable_device(struct pci_dev *dev); > void pcibios_set_master(struct pci_dev *dev);