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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FAKE_REPLY_C,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 1A48CC35242 for ; Fri, 24 Jan 2020 19:31:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7B062077C for ; Fri, 24 Jan 2020 19:31:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579894307; bh=Yos5tOqea+lsAAg57si5E3RrTRdqcrub8CC4qYiRuSk=; h=Date:From:To:Cc:Subject:In-Reply-To:List-ID:From; b=isG5OZ8SNztrLmnNxUDb7OPGjfUazrKetn7cIbHyRowAqw2fB89pHR1iVy8iJea1e LfqGP1GcCnY24SnVUeFjGDQb7wgoTymHfBx6h4mMonXCMjOfTQOyBtF3YCJuXRxNAe CjMTjVv8y53kVI0DAjxd5k/Nyz15qQxC3tUEIr7o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391918AbgAXTbq (ORCPT ); Fri, 24 Jan 2020 14:31:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:37158 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390186AbgAXTbp (ORCPT ); Fri, 24 Jan 2020 14:31:45 -0500 Received: from localhost (mobile-166-175-186-165.mycingular.net [166.175.186.165]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8B3052071E; Fri, 24 Jan 2020 19:31:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579894304; bh=Yos5tOqea+lsAAg57si5E3RrTRdqcrub8CC4qYiRuSk=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=2cLe8SweJIHy2T6kvegl/tSdIhGCnodJPelsnrD/+GIr+l5Eh8wFzncfimSpKwOXF Cy6kRqRyGgCs9PNjQaYHbr0u6XTqmmZc8FSDUw0gNvisxH4UxYIdnB1ZEbKr3ORfpD 3gygHmN1C91zWJMsePZ/L/lKWZayg61worbQb87o= Date: Fri, 24 Jan 2020 13:31:42 -0600 From: Bjorn Helgaas To: Chen Yu Cc: linux-pci@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Len Brown , "Rafael J. Wysocki" Subject: Re: [PATCH][RFC] PCI: Add "pci=blacklist_dev=" parameter to blacklist specific devices Message-ID: <20200124193142.GA33298@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200124144248.11719-1-yu.c.chen@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 24, 2020 at 10:42:48PM +0800, Chen Yu wrote: > It was found that on some platforms the bogus pci device might bring > troubles to the system. For example, on a MacBookPro the system could > not be power off or suspended due to internal pci resource confliction > between bogus pci device and [io 0x1804]. Another case is that, once > resumed from hibernation on a VM, the pci config space of a pci device > is corrupt. > > To narrow down and benefit future debugging for such kind of issues, > introduce the command line blacklist_dev=> to blacklist > such pci devices thus they will not be scanned thus not visible after > bootup. For example, > > pci.blacklist_dev=8086:293e > > forbid the audio device to be exposed to the OS. I'm not really a fan of this. I'd rather see some details about what the problem is so we can actually fix it. Ignoring the device doesn't mean the device is removed or even inactive. It may still be consuming address space that we need to avoid. Can you point us to bug reports about the issues you mentioned? > Signed-off-by: Chen Yu > --- > Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ > drivers/pci/pci.c | 17 +++++++++++++++++ > drivers/pci/pci.h | 1 + > drivers/pci/probe.c | 3 +++ > 4 files changed, 27 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index ade4e6ec23e0..cd4a47e236aa 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -3583,6 +3583,12 @@ > may put more devices in an IOMMU group. > force_floating [S390] Force usage of floating interrupts. > nomio [S390] Do not use MIO instructions. > + blacklist_dev=[; ...] > + Specify one or more PCI devices (in the format > + specified above) separated by semicolons. > + Each device specified will not be scanned thus > + will be invisible after boot up. This can be > + used for debugging purpose. > > pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power > Management. > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index e87196cc1a7f..0e3626a401f4 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -6393,6 +6393,19 @@ void __weak pci_fixup_cardbus(struct pci_bus *bus) > } > EXPORT_SYMBOL(pci_fixup_cardbus); > > +static const char *pci_blacklist_devs_param; > + > +bool pci_is_blacklist_dev(unsigned short vendor, unsigned short device) > +{ > + char search[10]; > + > + if (!pci_blacklist_devs_param) > + return false; > + sprintf(search, "%x:%x", vendor, device); > + > + return strstr(pci_blacklist_devs_param, search) ? true : false; > +} > + > static int __init pci_setup(char *str) > { > while (str) { > @@ -6451,6 +6464,8 @@ 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, "blacklist_dev=", 14)) { > + pci_blacklist_devs_param = str + 14; > } else { > pr_err("PCI: Unknown option `%s'\n", str); > } > @@ -6476,6 +6491,8 @@ static int __init pci_realloc_setup_params(void) > GFP_KERNEL); > disable_acs_redir_param = kstrdup(disable_acs_redir_param, GFP_KERNEL); > > + pci_blacklist_devs_param = kstrdup(pci_blacklist_devs_param, GFP_KERNEL); > + > return 0; > } > pure_initcall(pci_realloc_setup_params); > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index a0a53bd05a0b..01b8ab2da065 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -669,4 +669,5 @@ static inline int pci_acpi_program_hp_params(struct pci_dev *dev) > extern const struct attribute_group aspm_ctrl_attr_group; > #endif > > +bool pci_is_blacklist_dev(unsigned short vendor, unsigned short device); > #endif /* DRIVERS_PCI_H */ > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 512cb4312ddd..812ef901ecea 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -2271,6 +2271,9 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn) > if (!pci_bus_read_dev_vendor_id(bus, devfn, &l, 60*1000)) > return NULL; > > + if (pci_is_blacklist_dev(l & 0xffff, (l >> 16) & 0xffff)) > + return NULL; > + > dev = pci_alloc_dev(bus); > if (!dev) > return NULL; > -- > 2.17.1 >