From patchwork Thu May 24 21:48:14 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 920117 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=deltatee.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 40sNLX5Q0mz9s0q for ; Fri, 25 May 2018 07:48:52 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S969505AbeEXVsu (ORCPT ); Thu, 24 May 2018 17:48:50 -0400 Received: from ale.deltatee.com ([207.54.116.67]:39900 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S969433AbeEXVss (ORCPT ); Thu, 24 May 2018 17:48:48 -0400 Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1fLy6F-0005xc-No; Thu, 24 May 2018 15:48:45 -0600 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.89) (envelope-from ) id 1fLy6B-0003mP-Ua; Thu, 24 May 2018 15:48:39 -0600 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-doc@vger.kernel.org Cc: Stephen Bates , Christoph Hellwig , Bjorn Helgaas , Jonathan Corbet , Ingo Molnar , Thomas Gleixner , Christoffer Dall , "Paul E. McKenney" , Marc Zyngier , Kai-Heng Feng , Frederic Weisbecker , Dan Williams , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , Alex Williamson , =?utf-8?q?Christian_K=C3=B6nig?= , Logan Gunthorpe Date: Thu, 24 May 2018 15:48:14 -0600 Message-Id: <20180524214816.14485-2-logang@deltatee.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180524214816.14485-1-logang@deltatee.com> References: <20180524214816.14485-1-logang@deltatee.com> X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-doc@vger.kernel.org, sbates@raithlin.com, hch@lst.de, bhelgaas@google.com, corbet@lwn.net, tglx@linutronix.de, cdall@linaro.org, paulmck@linux.vnet.ibm.com, marc.zyngier@arm.com, kai.heng.feng@canonical.com, mingo@kernel.org, frederic@kernel.org, dan.j.williams@intel.com, benh@kernel.crashing.org, jglisse@redhat.com, alex.williamson@redhat.com, christian.koenig@amd.com, logang@deltatee.com X-SA-Exim-Mail-From: gunthorp@deltatee.com X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on ale.deltatee.com X-Spam-Level: X-Spam-Status: No, score=-8.7 required=5.0 tests=ALL_TRUSTED,BAYES_00, GREYLIST_ISWHITE,MYRULES_NO_TEXT autolearn=ham autolearn_force=no version=3.4.1 Subject: [PATCH 1/3] PCI: Make specifying PCI devices in kernel parameters reusable X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Separate out the code to match a PCI device with a string (typically originating from a kernel parameter) from the pci_specified_resource_alignment() function into its own helper function. While we are at it, this change fixes the kernel style of the function (fixing a number of long lines and extra parentheses). Additionally, make the analogous change to the kernel parameter documentation: Separating the description of how to specify a PCI device into it's own section at the head of the pci= parameter. Signed-off-by: Logan Gunthorpe Reviewed-by: Stephen Bates --- Documentation/admin-guide/kernel-parameters.txt | 26 +++- drivers/pci/pci.c | 153 +++++++++++++++--------- 2 files changed, 120 insertions(+), 59 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 11fc28ecdb6d..894aa516ceab 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2982,7 +2982,24 @@ See header of drivers/block/paride/pcd.c. See also Documentation/blockdev/paride.txt. - pci=option[,option...] [PCI] various PCI subsystem options: + pci=option[,option...] [PCI] various PCI subsystem options. + + Some options herein operate on a specific device + or a set of devices (). These are + specified in one of two formats: + + [:]:. + pci::[::] + + Note: the first format specifies a PCI + bus/slot/function address which may change + if new hardware is inserted, if motherboard + firmware changes, or due to changes caused + by other kernel parameters. The second format + selects devices using IDs from the + configuration space which may match multiple + devices in the system. + earlydump [X86] dump PCI config space before the kernel changes anything off [X86] don't probe for the PCI bus @@ -3111,11 +3128,10 @@ window. The default value is 64 megabytes. resource_alignment= Format: - [@][:]:.[; ...] - [@]pci::\ - [::][; ...] + [@][; ...] Specifies alignment and device to reassign - aligned memory resources. + aligned memory resources. How to + specify the device is described above. If is not specified, PAGE_SIZE is used as alignment. PCI-PCI bridge can be specified, if resource diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index dbfe7c4f3776..85fec5e2640b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -183,6 +183,88 @@ void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar) EXPORT_SYMBOL_GPL(pci_ioremap_wc_bar); #endif +/** + * pci_dev_str_match - test if a string matches a device + * @dev: the PCI device to test + * @p: string to match the device against + * @endptr: pointer to the string after the match + * + * Test if a string (typically from a kernel parameter) matches a + * specified. The string may be of one of two forms formats: + * + * [:]:. + * pci::[::] + * + * The first format specifies a PCI bus/slot/function address which + * may change if new hardware is inserted, if motherboard firmware changes, + * or due to changes caused in kernel parameters. + * + * The second format matches devices using IDs in the configuration + * space which may match multiple devices in the system. A value of 0 + * for any field will match all devices. + * + * Returns 1 if the string matches the device, 0 if it does not and + * a negative error code if the string cannot be parsed. + */ +static int pci_dev_str_match(struct pci_dev *dev, const char *p, + const char **endptr) +{ + int ret; + int seg, bus, slot, func, count; + unsigned short vendor, device, subsystem_vendor, subsystem_device; + + if (strncmp(p, "pci:", 4) == 0) { + /* PCI vendor/device (subvendor/subdevice) ids are specified */ + p += 4; + ret = sscanf(p, "%hx:%hx:%hx:%hx%n", &vendor, &device, + &subsystem_vendor, &subsystem_device, &count); + if (ret != 4) { + ret = sscanf(p, "%hx:%hx%n", &vendor, &device, &count); + if (ret != 2) + return -EINVAL; + + subsystem_vendor = 0; + subsystem_device = 0; + } + + p += count; + + if ((!vendor || vendor == dev->vendor) && + (!device || device == dev->device) && + (!subsystem_vendor || + subsystem_vendor == dev->subsystem_vendor) && + (!subsystem_device || + subsystem_device == dev->subsystem_device)) + goto found; + + } else { + /* PCI Bus,Slot,Function ids are specified */ + ret = sscanf(p, "%x:%x:%x.%x%n", &seg, &bus, &slot, + &func, &count); + if (ret != 4) { + seg = 0; + ret = sscanf(p, "%x:%x.%x%n", &bus, &slot, + &func, &count); + if (ret != 3) + return -EINVAL; + } + + p += count; + + if (seg == pci_domain_nr(dev->bus) && + bus == dev->bus->number && + slot == PCI_SLOT(dev->devfn) && + func == PCI_FUNC(dev->devfn)) + goto found; + } + + *endptr = p; + return 0; + +found: + *endptr = p; + return 1; +} static int __pci_find_next_cap_ttl(struct pci_bus *bus, unsigned int devfn, u8 pos, int cap, int *ttl) @@ -5462,10 +5544,10 @@ static DEFINE_SPINLOCK(resource_alignment_lock); static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, bool *resize) { - int seg, bus, slot, func, align_order, count; - unsigned short vendor, device, subsystem_vendor, subsystem_device; + int align_order, count; resource_size_t align = pcibios_default_alignment(); - char *p; + const char *p; + int ret; spin_lock(&resource_alignment_lock); p = resource_alignment_param; @@ -5485,58 +5567,21 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, } else { align_order = -1; } - if (strncmp(p, "pci:", 4) == 0) { - /* PCI vendor/device (subvendor/subdevice) ids are specified */ - p += 4; - if (sscanf(p, "%hx:%hx:%hx:%hx%n", - &vendor, &device, &subsystem_vendor, &subsystem_device, &count) != 4) { - if (sscanf(p, "%hx:%hx%n", &vendor, &device, &count) != 2) { - printk(KERN_ERR "PCI: Can't parse resource_alignment parameter: pci:%s\n", - p); - break; - } - subsystem_vendor = subsystem_device = 0; - } - p += count; - if ((!vendor || (vendor == dev->vendor)) && - (!device || (device == dev->device)) && - (!subsystem_vendor || (subsystem_vendor == dev->subsystem_vendor)) && - (!subsystem_device || (subsystem_device == dev->subsystem_device))) { - *resize = true; - if (align_order == -1) - align = PAGE_SIZE; - else - align = 1 << align_order; - /* Found */ - break; - } - } - else { - if (sscanf(p, "%x:%x:%x.%x%n", - &seg, &bus, &slot, &func, &count) != 4) { - seg = 0; - if (sscanf(p, "%x:%x.%x%n", - &bus, &slot, &func, &count) != 3) { - /* Invalid format */ - printk(KERN_ERR "PCI: Can't parse resource_alignment parameter: %s\n", - p); - break; - } - } - p += count; - if (seg == pci_domain_nr(dev->bus) && - bus == dev->bus->number && - slot == PCI_SLOT(dev->devfn) && - func == PCI_FUNC(dev->devfn)) { - *resize = true; - if (align_order == -1) - align = PAGE_SIZE; - else - align = 1 << align_order; - /* Found */ - break; - } + + ret = pci_dev_str_match(dev, p, &p); + if (ret == 1) { + *resize = true; + if (align_order == -1) + align = PAGE_SIZE; + else + align = 1 << align_order; + break; + } else if (ret < 0) { + pr_info("PCI: Can't parse resource_alignment parameter: pci:%s\n", + p); + break; } + if (*p != ';' && *p != ',') { /* End of param or invalid format */ break; From patchwork Thu May 24 21:48:15 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 920118 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=deltatee.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 40sNMC5ppWz9s0q for ; Fri, 25 May 2018 07:49:27 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S969576AbeEXVs6 (ORCPT ); Thu, 24 May 2018 17:48:58 -0400 Received: from ale.deltatee.com ([207.54.116.67]:39926 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966099AbeEXVss (ORCPT ); Thu, 24 May 2018 17:48:48 -0400 Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1fLy6F-0005xd-Np; Thu, 24 May 2018 15:48:47 -0600 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.89) (envelope-from ) id 1fLy6C-0003mS-1I; Thu, 24 May 2018 15:48:40 -0600 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-doc@vger.kernel.org Cc: Stephen Bates , Christoph Hellwig , Bjorn Helgaas , Jonathan Corbet , Ingo Molnar , Thomas Gleixner , Christoffer Dall , "Paul E. McKenney" , Marc Zyngier , Kai-Heng Feng , Frederic Weisbecker , Dan Williams , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , Alex Williamson , =?utf-8?q?Christian_K=C3=B6nig?= , Logan Gunthorpe Date: Thu, 24 May 2018 15:48:15 -0600 Message-Id: <20180524214816.14485-3-logang@deltatee.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180524214816.14485-1-logang@deltatee.com> References: <20180524214816.14485-1-logang@deltatee.com> X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-doc@vger.kernel.org, sbates@raithlin.com, hch@lst.de, bhelgaas@google.com, corbet@lwn.net, tglx@linutronix.de, cdall@linaro.org, paulmck@linux.vnet.ibm.com, marc.zyngier@arm.com, kai.heng.feng@canonical.com, mingo@kernel.org, frederic@kernel.org, dan.j.williams@intel.com, benh@kernel.crashing.org, jglisse@redhat.com, alex.williamson@redhat.com, christian.koenig@amd.com, logang@deltatee.com X-SA-Exim-Mail-From: gunthorp@deltatee.com X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on ale.deltatee.com X-Spam-Level: X-Spam-Status: No, score=-8.5 required=5.0 tests=ALL_TRUSTED,BAYES_00, GREYLIST_ISWHITE,MYRULES_FREE,MYRULES_NO_TEXT autolearn=ham autolearn_force=no version=3.4.1 Subject: [PATCH 2/3] PCI: Allow specifying devices using a base bus and path of devfns X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org When specifying PCI devices on the kernel command line using a BDF, the bus numbers can change when adding or replacing a device, changing motherboard firmware, or applying kernel parameters like pci=assign-buses. When this happens, it is usually undesirable to apply whatever command line tweak to the wrong device. Therefore, it is useful to be able to specify devices with a base bus number and the path of devfns needed to get to it. (Similar to the "device scope" structure in the Intel VT-d spec, Section 8.3.1.) Thus, we add an option to specify devices in the following format: path:[:]:./.[/ ...] The path can be any segment within the PCI hierarchy of any length and determined through the use of 'lspci -t'. When specified this way, it is less likely that a renumbered bus will result in a valid device specification and the tweak won't be applied to the wrong device. Signed-off-by: Logan Gunthorpe Reviewed-by: Stephen Bates --- Documentation/admin-guide/kernel-parameters.txt | 12 ++- drivers/pci/pci.c | 106 +++++++++++++++++++++++- 2 files changed, 112 insertions(+), 6 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 894aa516ceab..519ab95bb418 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2986,9 +2986,10 @@ Some options herein operate on a specific device or a set of devices (). These are - specified in one of two formats: + specified in one of three formats: [:]:. + path:[:]:./.[/ ...] pci::[::] Note: the first format specifies a PCI @@ -2996,9 +2997,12 @@ if new hardware is inserted, if motherboard firmware changes, or due to changes caused by other kernel parameters. The second format - selects devices using IDs from the - configuration space which may match multiple - devices in the system. + specifies a path from a device through + a path of multiple slot/function addresses + (this is more robust against renumbering + issues). The third format selects devices using + IDs from the configuration space which may match + multiple devices in the system. earlydump [X86] dump PCI config space before the kernel changes anything diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 85fec5e2640b..53ea0d7b02ce 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -184,22 +184,116 @@ EXPORT_SYMBOL_GPL(pci_ioremap_wc_bar); #endif /** + * pci_dev_str_match_path - test if a path string matches a device + * @dev: the PCI device to test + * @p: string to match the device against + * @endptr: pointer to the string after the match + * + * Test if a string (typically from a kernel parameter) formated as a + * path of slot/function addresses matches a PCI device. The string must + * be of the form: + * + * [:]:./.[/ ...] + * + * A path for a device can be obtained using 'lspci -t'. Using a path + * is more robust against renumbering of devices than using only + * a single bus, slot and function address. + * + * Returns 1 if the string matches the device, 0 if it does not and + * a negative error code if it fails to parse the string. + */ +static int pci_dev_str_match_path(struct pci_dev *dev, const char *p, + const char **endptr) +{ + int ret; + int seg, bus, slot, func, count; + u8 *devfn_path; + int num_devfn = 0; + struct pci_dev *tmp; + + ret = sscanf(p, "%x:%x:%x.%x%n", &seg, &bus, &slot, + &func, &count); + if (ret != 4) { + seg = 0; + ret = sscanf(p, "%x:%x.%x%n", &bus, &slot, + &func, &count); + if (ret != 3) + return -EINVAL; + } + + p += count; + + devfn_path = kmalloc(PAGE_SIZE, GFP_KERNEL); + devfn_path[num_devfn++] = PCI_DEVFN(slot, func); + + while (*p && *p != ',' && *p != ';') { + ret = sscanf(p, "/%x.%x%n", &slot, &func, &count); + if (ret != 2) { + ret = -EINVAL; + goto free_and_exit; + } + + p += count; + devfn_path[num_devfn++] = PCI_DEVFN(slot, func); + if (num_devfn >= PAGE_SIZE) { + ret = -EINVAL; + goto free_and_exit; + } + } + + *endptr = p; + ret = 0; + + if (seg != pci_domain_nr(dev->bus)) + goto free_and_exit; + + pci_dev_get(dev); + while (num_devfn > 0 && dev) { + num_devfn--; + + if (devfn_path[num_devfn] != dev->devfn) + goto put_and_exit; + + if (num_devfn == 0 && bus == dev->bus->number) { + ret = 1; + goto put_and_exit; + } + + tmp = pci_dev_get(pci_upstream_bridge(dev)); + pci_dev_put(dev); + dev = tmp; + } + +put_and_exit: + pci_dev_put(dev); +free_and_exit: + kfree(devfn_path); + return ret; +} + +/** * pci_dev_str_match - test if a string matches a device * @dev: the PCI device to test * @p: string to match the device against * @endptr: pointer to the string after the match * * Test if a string (typically from a kernel parameter) matches a - * specified. The string may be of one of two forms formats: + * specified. The string may be of one of three formats: * * [:]:. + * path:[:]:./.[/ ...] * pci::[::] * * The first format specifies a PCI bus/slot/function address which * may change if new hardware is inserted, if motherboard firmware changes, * or due to changes caused in kernel parameters. * - * The second format matches devices using IDs in the configuration + * The second format specifies a PCI bus/slot/function root address and + * a path of slot/function addresses to the specific device from the root. + * The path for a device can be determined through the use of 'lspci -t'. + * This format is more robust against renumbering issues than the first format. + + * The third format matches devices using IDs in the configuration * space which may match multiple devices in the system. A value of 0 * for any field will match all devices. * @@ -236,7 +330,15 @@ static int pci_dev_str_match(struct pci_dev *dev, const char *p, (!subsystem_device || subsystem_device == dev->subsystem_device)) goto found; + } else if (strncmp(p, "path:", 5) == 0) { + /* PCI Root Bus and a path of Slot,Function IDs */ + p += 5; + ret = pci_dev_str_match_path(dev, p, &p); + if (ret < 0) + return ret; + else if (ret) + goto found; } else { /* PCI Bus,Slot,Function ids are specified */ ret = sscanf(p, "%x:%x:%x.%x%n", &seg, &bus, &slot, From patchwork Thu May 24 21:48:16 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 920119 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=deltatee.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 40sNML4ktKz9s0q for ; Fri, 25 May 2018 07:49:34 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S971689AbeEXVs4 (ORCPT ); Thu, 24 May 2018 17:48:56 -0400 Received: from ale.deltatee.com ([207.54.116.67]:39916 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S969460AbeEXVss (ORCPT ); Thu, 24 May 2018 17:48:48 -0400 Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1fLy6F-0005xe-Np; Thu, 24 May 2018 15:48:46 -0600 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.89) (envelope-from ) id 1fLy6C-0003mV-4X; Thu, 24 May 2018 15:48:40 -0600 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-doc@vger.kernel.org Cc: Stephen Bates , Christoph Hellwig , Bjorn Helgaas , Jonathan Corbet , Ingo Molnar , Thomas Gleixner , Christoffer Dall , "Paul E. McKenney" , Marc Zyngier , Kai-Heng Feng , Frederic Weisbecker , Dan Williams , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , Alex Williamson , =?utf-8?q?Christian_K=C3=B6nig?= , Logan Gunthorpe Date: Thu, 24 May 2018 15:48:16 -0600 Message-Id: <20180524214816.14485-4-logang@deltatee.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180524214816.14485-1-logang@deltatee.com> References: <20180524214816.14485-1-logang@deltatee.com> X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-doc@vger.kernel.org, sbates@raithlin.com, hch@lst.de, bhelgaas@google.com, corbet@lwn.net, tglx@linutronix.de, cdall@linaro.org, paulmck@linux.vnet.ibm.com, marc.zyngier@arm.com, kai.heng.feng@canonical.com, mingo@kernel.org, frederic@kernel.org, dan.j.williams@intel.com, benh@kernel.crashing.org, jglisse@redhat.com, alex.williamson@redhat.com, christian.koenig@amd.com, logang@deltatee.com X-SA-Exim-Mail-From: gunthorp@deltatee.com X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on ale.deltatee.com X-Spam-Level: X-Spam-Status: No, score=-8.7 required=5.0 tests=ALL_TRUSTED,BAYES_00, GREYLIST_ISWHITE,MYRULES_NO_TEXT autolearn=ham autolearn_force=no version=3.4.1 Subject: [PATCH 3/3] PCI: Introduce the disable_acs_redir parameter X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org In order to support P2P traffic on a segment of the PCI hierarchy, we must be able to disable the ACS redirect bits for select PCI bridges. The bridges must be selected before the devices are discovered by the kernel and the IOMMU groups created. Therefore, a kernel command line parameter is created to specify devices which must have their ACS bits disabled. The new parameter takes a list of devices separated by a semicolon. Each device specified will have it's ACS redirect bits disabled. This is similar to the existing 'resource_alignment' parameter and just like it we also create a sysfs bus attribute which can be used to read the parameter. Writing the parameter is not supported as it would require forcibly hot plugging the affected device as well as all devices whose IOMMU groups might change. The ACS Request P2P Request Redirect, P2P Completion Redirect and P2P Egress Control bits are disabled which is sufficient to always allow passing P2P traffic uninterrupted. The bits are set after the kernel (optionally) enables the ACS bits itself. It is also done regardless of whether the kernel sets the bits or not seeing some BIOS firmware is known to set the bits on boot. Signed-off-by: Logan Gunthorpe Reviewed-by: Stephen Bates --- Documentation/admin-guide/kernel-parameters.txt | 9 +++ drivers/pci/pci.c | 103 +++++++++++++++++++++++- 2 files changed, 110 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 519ab95bb418..215285c4772d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3176,6 +3176,15 @@ Adding the window is slightly risky (it may conflict with unreported devices), so this taints the kernel. + disable_acs_redir=[; ...] + Specify one or more PCI devices (in the format + specified above) separated by semicolons. + Each device specified will have the PCI ACS + redirect capabilities forced off which will + allow P2P traffic between devices through + bridges without forcing it upstream. Note: + this removes isolation between devices and + will make the IOMMU groups less granular. 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 53ea0d7b02ce..3465895a55ab 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2998,6 +2998,92 @@ void pci_request_acs(void) pci_acs_enable = 1; } +#define DISABLE_ACS_REDIR_PARAM_SIZE COMMAND_LINE_SIZE +static char disable_acs_redir_param[DISABLE_ACS_REDIR_PARAM_SIZE] = {0}; +static DEFINE_SPINLOCK(disable_acs_redir_lock); + +static ssize_t pci_set_disable_acs_redir_param(const char *buf, size_t count) +{ + if (count > DISABLE_ACS_REDIR_PARAM_SIZE - 1) + count = DISABLE_ACS_REDIR_PARAM_SIZE - 1; + spin_lock(&disable_acs_redir_lock); + strncpy(disable_acs_redir_param, buf, count); + disable_acs_redir_param[count] = '\0'; + spin_unlock(&disable_acs_redir_lock); + return count; +} + +static ssize_t pci_disable_acs_redir_show(struct bus_type *bus, char *buf) +{ + size_t count; + + spin_lock(&disable_acs_redir_lock); + count = snprintf(buf, PAGE_SIZE, "%s\n", disable_acs_redir_param); + spin_unlock(&disable_acs_redir_lock); + return count; +} + +static BUS_ATTR(disable_acs_redir, 0444, pci_disable_acs_redir_show, NULL); + +static int __init pci_disable_acs_redir_sysfs_init(void) +{ + return bus_create_file(&pci_bus_type, &bus_attr_disable_acs_redir); +} +late_initcall(pci_disable_acs_redir_sysfs_init); + +/** + * pci_disable_acs_redir - disable ACS redirect capabilities + * @dev: the PCI device + * + * For only devices specified in the disable_acs_redir parameter. + */ +static void pci_disable_acs_redir(struct pci_dev *dev) +{ + int ret = 0; + const char *p; + int pos; + u16 ctrl; + + spin_lock(&disable_acs_redir_lock); + + p = disable_acs_redir_param; + while (*p) { + ret = pci_dev_str_match(dev, p, &p); + if (ret < 0) { + pr_info_once("PCI: Can't parse disable_acs_redir parameter: %s\n", + disable_acs_redir_param); + + break; + } else if (ret == 1) { + /* Found a match */ + break; + } + + if (*p != ';' && *p != ',') { + /* End of param or invalid format */ + break; + } + p++; + } + spin_unlock(&disable_acs_redir_lock); + + if (ret != 1) + return; + + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS); + if (!pos) + return; + + pci_read_config_word(dev, pos + PCI_ACS_CTRL, &ctrl); + + /* P2P Request & Completion Redirect */ + ctrl &= ~(PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_EC); + + pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl); + + pci_info(dev, "disabled ACS redirect\n"); +} + /** * pci_std_enable_acs - enable ACS on devices using standard ACS capabilites * @dev: the PCI device @@ -3037,12 +3123,22 @@ static void pci_std_enable_acs(struct pci_dev *dev) void pci_enable_acs(struct pci_dev *dev) { if (!pci_acs_enable) - return; + goto disable_acs_redir; if (!pci_dev_specific_enable_acs(dev)) - return; + goto disable_acs_redir; pci_std_enable_acs(dev); + +disable_acs_redir: + /* + * Note: pci_disable_acs_redir() must be called even if + * ACS is not enabled by the kernel because the firmware + * may have unexpectedly set the flags. So if we are told + * to disable it, we should always disable it after setting + * the kernel's default preferences. + */ + pci_disable_acs_redir(dev); } static bool pci_acs_flags_enabled(struct pci_dev *pdev, u16 acs_flags) @@ -5995,6 +6091,9 @@ static int __init pci_setup(char *str) pcie_bus_config = PCIE_BUS_PEER2PEER; } else if (!strncmp(str, "pcie_scan_all", 13)) { pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS); + } else if (!strncmp(str, "disable_acs_redir=", 18)) { + pci_set_disable_acs_redir_param(str + 18, + strlen(str + 18)); } else { printk(KERN_ERR "PCI: Unknown option `%s'\n", str);