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1// SPDX-License-Identifier: GPL-2.02/*3 * PCI Backend - Provides restricted access to the real PCI bus topology4 * to the frontend5 *6 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>7 */8 9#include <linux/list.h>10#include <linux/pci.h>11#include <linux/mutex.h>12#include "pciback.h"13 14struct passthrough_dev_data {15 /* Access to dev_list must be protected by lock */16 struct list_head dev_list;17 struct mutex lock;18};19 20static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev,21 unsigned int domain,22 unsigned int bus,23 unsigned int devfn)24{25 struct passthrough_dev_data *dev_data = pdev->pci_dev_data;26 struct pci_dev_entry *dev_entry;27 struct pci_dev *dev = NULL;28 29 mutex_lock(&dev_data->lock);30 31 list_for_each_entry(dev_entry, &dev_data->dev_list, list) {32 if (domain == (unsigned int)pci_domain_nr(dev_entry->dev->bus)33 && bus == (unsigned int)dev_entry->dev->bus->number34 && devfn == dev_entry->dev->devfn) {35 dev = dev_entry->dev;36 break;37 }38 }39 40 mutex_unlock(&dev_data->lock);41 42 return dev;43}44 45static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,46 struct pci_dev *dev,47 int devid, publish_pci_dev_cb publish_cb)48{49 struct passthrough_dev_data *dev_data = pdev->pci_dev_data;50 struct pci_dev_entry *dev_entry;51 unsigned int domain, bus, devfn;52 int err;53 54 dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);55 if (!dev_entry)56 return -ENOMEM;57 dev_entry->dev = dev;58 59 mutex_lock(&dev_data->lock);60 list_add_tail(&dev_entry->list, &dev_data->dev_list);61 mutex_unlock(&dev_data->lock);62 63 /* Publish this device. */64 domain = (unsigned int)pci_domain_nr(dev->bus);65 bus = (unsigned int)dev->bus->number;66 devfn = dev->devfn;67 err = publish_cb(pdev, domain, bus, devfn, devid);68 69 return err;70}71 72static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,73 struct pci_dev *dev, bool lock)74{75 struct passthrough_dev_data *dev_data = pdev->pci_dev_data;76 struct pci_dev_entry *dev_entry, *t;77 struct pci_dev *found_dev = NULL;78 79 mutex_lock(&dev_data->lock);80 81 list_for_each_entry_safe(dev_entry, t, &dev_data->dev_list, list) {82 if (dev_entry->dev == dev) {83 list_del(&dev_entry->list);84 found_dev = dev_entry->dev;85 kfree(dev_entry);86 }87 }88 89 mutex_unlock(&dev_data->lock);90 91 if (found_dev) {92 if (lock)93 device_lock(&found_dev->dev);94 pcistub_put_pci_dev(found_dev);95 if (lock)96 device_unlock(&found_dev->dev);97 }98}99 100static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev)101{102 struct passthrough_dev_data *dev_data;103 104 dev_data = kmalloc(sizeof(*dev_data), GFP_KERNEL);105 if (!dev_data)106 return -ENOMEM;107 108 mutex_init(&dev_data->lock);109 110 INIT_LIST_HEAD(&dev_data->dev_list);111 112 pdev->pci_dev_data = dev_data;113 114 return 0;115}116 117static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,118 publish_pci_root_cb publish_root_cb)119{120 int err = 0;121 struct passthrough_dev_data *dev_data = pdev->pci_dev_data;122 struct pci_dev_entry *dev_entry, *e;123 struct pci_dev *dev;124 int found;125 unsigned int domain, bus;126 127 mutex_lock(&dev_data->lock);128 129 list_for_each_entry(dev_entry, &dev_data->dev_list, list) {130 /* Only publish this device as a root if none of its131 * parent bridges are exported132 */133 found = 0;134 dev = dev_entry->dev->bus->self;135 for (; !found && dev != NULL; dev = dev->bus->self) {136 list_for_each_entry(e, &dev_data->dev_list, list) {137 if (dev == e->dev) {138 found = 1;139 break;140 }141 }142 }143 144 domain = (unsigned int)pci_domain_nr(dev_entry->dev->bus);145 bus = (unsigned int)dev_entry->dev->bus->number;146 147 if (!found) {148 err = publish_root_cb(pdev, domain, bus);149 if (err)150 break;151 }152 }153 154 mutex_unlock(&dev_data->lock);155 156 return err;157}158 159static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev)160{161 struct passthrough_dev_data *dev_data = pdev->pci_dev_data;162 struct pci_dev_entry *dev_entry, *t;163 164 list_for_each_entry_safe(dev_entry, t, &dev_data->dev_list, list) {165 struct pci_dev *dev = dev_entry->dev;166 list_del(&dev_entry->list);167 device_lock(&dev->dev);168 pcistub_put_pci_dev(dev);169 device_unlock(&dev->dev);170 kfree(dev_entry);171 }172 173 kfree(dev_data);174 pdev->pci_dev_data = NULL;175}176 177static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,178 struct xen_pcibk_device *pdev,179 unsigned int *domain, unsigned int *bus,180 unsigned int *devfn)181{182 *domain = pci_domain_nr(pcidev->bus);183 *bus = pcidev->bus->number;184 *devfn = pcidev->devfn;185 return 1;186}187 188const struct xen_pcibk_backend xen_pcibk_passthrough_backend = {189 .name = "passthrough",190 .init = __xen_pcibk_init_devices,191 .free = __xen_pcibk_release_devices,192 .find = __xen_pcibk_get_pcifront_dev,193 .publish = __xen_pcibk_publish_pci_roots,194 .release = __xen_pcibk_release_pci_dev,195 .add = __xen_pcibk_add_pci_dev,196 .get = __xen_pcibk_get_pci_dev,197};198