kernel/drivers/xen/xen-pciback/passthrough.c

   1 /*
   2  * PCI Backend - Provides restricted access to the real PCI bus topology
   3  *               to the frontend
   4  *
   5  *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
   6  */
   7
   8 #include <linux/list.h>
   9 #include <linux/pci.h>
  10 #include <linux/mutex.h>
  11 #include "pciback.h"
  12
  13 struct passthrough_dev_data {
  14         /* Access to dev_list must be protected by lock */
  15         struct list_head dev_list;
  16         struct mutex lock;
  17 };
  18
  19 static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev,
  20                                                unsigned int domain,
  21                                                unsigned int bus,
  22                                                unsigned int devfn)
  23 {
  24         struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
  25         struct pci_dev_entry *dev_entry;
  26         struct pci_dev *dev = NULL;
  27
  28         mutex_lock(&dev_data->lock);
  29
  30         list_for_each_entry(dev_entry, &dev_data->dev_list, list) {
  31                 if (domain == (unsigned int)pci_domain_nr(dev_entry->dev->bus)
  32                     && bus == (unsigned int)dev_entry->dev->bus->number
  33                     && devfn == dev_entry->dev->devfn) {
  34                         dev = dev_entry->dev;
  35                         break;
  36                 }
  37         }
  38
  39         mutex_unlock(&dev_data->lock);
  40
  41         return dev;
  42 }
  43
  44 static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
  45                                    struct pci_dev *dev,
  46                                    int devid, publish_pci_dev_cb publish_cb)
  47 {
  48         struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
  49         struct pci_dev_entry *dev_entry;
  50         unsigned int domain, bus, devfn;
  51         int err;
  52
  53         dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
  54         if (!dev_entry)
  55                 return -ENOMEM;
  56         dev_entry->dev = dev;
  57
  58         mutex_lock(&dev_data->lock);
  59         list_add_tail(&dev_entry->list, &dev_data->dev_list);
  60         mutex_unlock(&dev_data->lock);
  61
  62         /* Publish this device. */
  63         domain = (unsigned int)pci_domain_nr(dev->bus);
  64         bus = (unsigned int)dev->bus->number;
  65         devfn = dev->devfn;
  66         err = publish_cb(pdev, domain, bus, devfn, devid);
  67
  68         return err;
  69 }
  70
  71 static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
  72                                         struct pci_dev *dev, bool lock)
  73 {
  74         struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
  75         struct pci_dev_entry *dev_entry, *t;
  76         struct pci_dev *found_dev = NULL;
  77
  78         mutex_lock(&dev_data->lock);
  79
  80         list_for_each_entry_safe(dev_entry, t, &dev_data->dev_list, list) {
  81                 if (dev_entry->dev == dev) {
  82                         list_del(&dev_entry->list);
  83                         found_dev = dev_entry->dev;
  84                         kfree(dev_entry);
  85                 }
  86         }
  87
  88         mutex_unlock(&dev_data->lock);
  89
  90         if (found_dev) {
  91                 if (lock)
  92                         device_lock(&found_dev->dev);
  93                 pcistub_put_pci_dev(found_dev);
  94                 if (lock)
  95                         device_unlock(&found_dev->dev);
  96         }
  97 }
  98
  99 static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
 100 {
 101         struct passthrough_dev_data *dev_data;
 102
 103         dev_data = kmalloc(sizeof(*dev_data), GFP_KERNEL);
 104         if (!dev_data)
 105                 return -ENOMEM;
 106
 107         mutex_init(&dev_data->lock);
 108
 109         INIT_LIST_HEAD(&dev_data->dev_list);
 110
 111         pdev->pci_dev_data = dev_data;
 112
 113         return 0;
 114 }
 115
 116 static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
 117                                          publish_pci_root_cb publish_root_cb)
 118 {
 119         int err = 0;
 120         struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
 121         struct pci_dev_entry *dev_entry, *e;
 122         struct pci_dev *dev;
 123         int found;
 124         unsigned int domain, bus;
 125
 126         mutex_lock(&dev_data->lock);
 127
 128         list_for_each_entry(dev_entry, &dev_data->dev_list, list) {
 129                 /* Only publish this device as a root if none of its
 130                  * parent bridges are exported
 131                  */
 132                 found = 0;
 133                 dev = dev_entry->dev->bus->self;
 134                 for (; !found && dev != NULL; dev = dev->bus->self) {
 135                         list_for_each_entry(e, &dev_data->dev_list, list) {
 136                                 if (dev == e->dev) {
 137                                         found = 1;
 138                                         break;
 139                                 }
 140                         }
 141                 }
 142
 143                 domain = (unsigned int)pci_domain_nr(dev_entry->dev->bus);
 144                 bus = (unsigned int)dev_entry->dev->bus->number;
 145
 146                 if (!found) {
 147                         err = publish_root_cb(pdev, domain, bus);
 148                         if (err)
 149                                 break;
 150                 }
 151         }
 152
 153         mutex_unlock(&dev_data->lock);
 154
 155         return err;
 156 }
 157
 158 static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
 159 {
 160         struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
 161         struct pci_dev_entry *dev_entry, *t;
 162
 163         list_for_each_entry_safe(dev_entry, t, &dev_data->dev_list, list) {
 164                 struct pci_dev *dev = dev_entry->dev;
 165                 list_del(&dev_entry->list);
 166                 device_lock(&dev->dev);
 167                 pcistub_put_pci_dev(dev);
 168                 device_unlock(&dev->dev);
 169                 kfree(dev_entry);
 170         }
 171
 172         kfree(dev_data);
 173         pdev->pci_dev_data = NULL;
 174 }
 175
 176 static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
 177                                         struct xen_pcibk_device *pdev,
 178                                         unsigned int *domain, unsigned int *bus,
 179                                         unsigned int *devfn)
 180 {
 181         *domain = pci_domain_nr(pcidev->bus);
 182         *bus = pcidev->bus->number;
 183         *devfn = pcidev->devfn;
 184         return 1;
 185 }
 186
 187 const struct xen_pcibk_backend xen_pcibk_passthrough_backend = {
 188         .name           = "passthrough",
 189         .init           = __xen_pcibk_init_devices,
 190         .free           = __xen_pcibk_release_devices,
 191         .find           = __xen_pcibk_get_pcifront_dev,
 192         .publish        = __xen_pcibk_publish_pci_roots,
 193         .release        = __xen_pcibk_release_pci_dev,
 194         .add            = __xen_pcibk_add_pci_dev,
 195         .get            = __xen_pcibk_get_pci_dev,
 196 };