drivers/xen/xen-pciback/vpci.c

   1 /*
   2  * PCI Backend - Provides a Virtual PCI bus (with real devices)
   3  *               to the frontend
   4  *
   5  *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/list.h>
  11 #include <linux/slab.h>
  12 #include <linux/pci.h>
  13 #include <linux/mutex.h>
  14 #include "pciback.h"
  15
  16 #define PCI_SLOT_MAX 32
  17
  18 struct vpci_dev_data {
  19         /* Access to dev_list must be protected by lock */
  20         struct list_head dev_list[PCI_SLOT_MAX];
  21         struct mutex lock;
  22 };
  23
  24 static inline struct list_head *list_first(struct list_head *head)
  25 {
  26         return head->next;
  27 }
  28
  29 static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev,
  30                                                unsigned int domain,
  31                                                unsigned int bus,
  32                                                unsigned int devfn)
  33 {
  34         struct pci_dev_entry *entry;
  35         struct pci_dev *dev = NULL;
  36         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
  37
  38         if (domain != 0 || bus != 0)
  39                 return NULL;
  40
  41         if (PCI_SLOT(devfn) < PCI_SLOT_MAX) {
  42                 mutex_lock(&vpci_dev->lock);
  43
  44                 list_for_each_entry(entry,
  45                                     &vpci_dev->dev_list[PCI_SLOT(devfn)],
  46                                     list) {
  47                         if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) {
  48                                 dev = entry->dev;
  49                                 break;
  50                         }
  51                 }
  52
  53                 mutex_unlock(&vpci_dev->lock);
  54         }
  55         return dev;
  56 }
  57
  58 static inline int match_slot(struct pci_dev *l, struct pci_dev *r)
  59 {
  60         if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus)
  61             && l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn))
  62                 return 1;
  63
  64         return 0;
  65 }
  66
  67 static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
  68                                    struct pci_dev *dev, int devid,
  69                                    publish_pci_dev_cb publish_cb)
  70 {
  71         int err = 0, slot, func = -1;
  72         struct pci_dev_entry *t, *dev_entry;
  73         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
  74
  75         if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) {
  76                 err = -EFAULT;
  77                 xenbus_dev_fatal(pdev->xdev, err,
  78                                  "Can't export bridges on the virtual PCI bus");
  79                 goto out;
  80         }
  81
  82         dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
  83         if (!dev_entry) {
  84                 err = -ENOMEM;
  85                 xenbus_dev_fatal(pdev->xdev, err,
  86                                  "Error adding entry to virtual PCI bus");
  87                 goto out;
  88         }
  89
  90         dev_entry->dev = dev;
  91
  92         mutex_lock(&vpci_dev->lock);
  93
  94         /*
  95          * Keep multi-function devices together on the virtual PCI bus, except
  96          * virtual functions.
  97          */
  98         if (!dev->is_virtfn) {
  99                 for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 100                         if (list_empty(&vpci_dev->dev_list[slot]))
 101                                 continue;
 102
 103                         t = list_entry(list_first(&vpci_dev->dev_list[slot]),
 104                                        struct pci_dev_entry, list);
 105
 106                         if (match_slot(dev, t->dev)) {
 107                                 pr_info("vpci: %s: assign to virtual slot %d func %d\n",
 108                                         pci_name(dev), slot,
 109                                         PCI_FUNC(dev->devfn));
 110                                 list_add_tail(&dev_entry->list,
 111                                               &vpci_dev->dev_list[slot]);
 112                                 func = PCI_FUNC(dev->devfn);
 113                                 goto unlock;
 114                         }
 115                 }
 116         }
 117
 118         /* Assign to a new slot on the virtual PCI bus */
 119         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 120                 if (list_empty(&vpci_dev->dev_list[slot])) {
 121                         pr_info("vpci: %s: assign to virtual slot %d\n",
 122                                 pci_name(dev), slot);
 123                         list_add_tail(&dev_entry->list,
 124                                       &vpci_dev->dev_list[slot]);
 125                         func = dev->is_virtfn ? 0 : PCI_FUNC(dev->devfn);
 126                         goto unlock;
 127                 }
 128         }
 129
 130         err = -ENOMEM;
 131         xenbus_dev_fatal(pdev->xdev, err,
 132                          "No more space on root virtual PCI bus");
 133
 134 unlock:
 135         mutex_unlock(&vpci_dev->lock);
 136
 137         /* Publish this device. */
 138         if (!err)
 139                 err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid);
 140         else
 141                 kfree(dev_entry);
 142
 143 out:
 144         return err;
 145 }
 146
 147 static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
 148                                         struct pci_dev *dev, bool lock)
 149 {
 150         int slot;
 151         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 152         struct pci_dev *found_dev = NULL;
 153
 154         mutex_lock(&vpci_dev->lock);
 155
 156         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 157                 struct pci_dev_entry *e;
 158
 159                 list_for_each_entry(e, &vpci_dev->dev_list[slot], list) {
 160                         if (e->dev == dev) {
 161                                 list_del(&e->list);
 162                                 found_dev = e->dev;
 163                                 kfree(e);
 164                                 goto out;
 165                         }
 166                 }
 167         }
 168
 169 out:
 170         mutex_unlock(&vpci_dev->lock);
 171
 172         if (found_dev) {
 173                 if (lock)
 174                         device_lock(&found_dev->dev);
 175                 pcistub_put_pci_dev(found_dev);
 176                 if (lock)
 177                         device_unlock(&found_dev->dev);
 178         }
 179 }
 180
 181 static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
 182 {
 183         int slot;
 184         struct vpci_dev_data *vpci_dev;
 185
 186         vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL);
 187         if (!vpci_dev)
 188                 return -ENOMEM;
 189
 190         mutex_init(&vpci_dev->lock);
 191
 192         for (slot = 0; slot < PCI_SLOT_MAX; slot++)
 193                 INIT_LIST_HEAD(&vpci_dev->dev_list[slot]);
 194
 195         pdev->pci_dev_data = vpci_dev;
 196
 197         return 0;
 198 }
 199
 200 static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
 201                                          publish_pci_root_cb publish_cb)
 202 {
 203         /* The Virtual PCI bus has only one root */
 204         return publish_cb(pdev, 0, 0);
 205 }
 206
 207 static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
 208 {
 209         int slot;
 210         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 211
 212         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 213                 struct pci_dev_entry *e, *tmp;
 214                 list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
 215                                          list) {
 216                         struct pci_dev *dev = e->dev;
 217                         list_del(&e->list);
 218                         device_lock(&dev->dev);
 219                         pcistub_put_pci_dev(dev);
 220                         device_unlock(&dev->dev);
 221                         kfree(e);
 222                 }
 223         }
 224
 225         kfree(vpci_dev);
 226         pdev->pci_dev_data = NULL;
 227 }
 228
 229 static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
 230                                         struct xen_pcibk_device *pdev,
 231                                         unsigned int *domain, unsigned int *bus,
 232                                         unsigned int *devfn)
 233 {
 234         struct pci_dev_entry *entry;
 235         struct pci_dev *dev = NULL;
 236         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 237         int found = 0, slot;
 238
 239         mutex_lock(&vpci_dev->lock);
 240         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 241                 list_for_each_entry(entry,
 242                             &vpci_dev->dev_list[slot],
 243                             list) {
 244                         dev = entry->dev;
 245                         if (dev && dev->bus->number == pcidev->bus->number
 246                                 && pci_domain_nr(dev->bus) ==
 247                                         pci_domain_nr(pcidev->bus)
 248                                 && dev->devfn == pcidev->devfn) {
 249                                 found = 1;
 250                                 *domain = 0;
 251                                 *bus = 0;
 252                                 *devfn = PCI_DEVFN(slot,
 253                                          PCI_FUNC(pcidev->devfn));
 254                         }
 255                 }
 256         }
 257         mutex_unlock(&vpci_dev->lock);
 258         return found;
 259 }
 260
 261 const struct xen_pcibk_backend xen_pcibk_vpci_backend = {
 262         .name           = "vpci",
 263         .init           = __xen_pcibk_init_devices,
 264         .free           = __xen_pcibk_release_devices,
 265         .find           = __xen_pcibk_get_pcifront_dev,
 266         .publish        = __xen_pcibk_publish_pci_roots,
 267         .release        = __xen_pcibk_release_pci_dev,
 268         .add            = __xen_pcibk_add_pci_dev,
 269         .get            = __xen_pcibk_get_pci_dev,
 270 };