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