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/spinlock.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         spinlock_t 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         unsigned long flags;
  36
  37         if (domain != 0 || bus != 0)
  38                 return NULL;
  39
  40         if (PCI_SLOT(devfn) < PCI_SLOT_MAX) {
  41                 spin_lock_irqsave(&vpci_dev->lock, flags);
  42
  43                 list_for_each_entry(entry,
  44                                     &vpci_dev->dev_list[PCI_SLOT(devfn)],
  45                                     list) {
  46                         if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) {
  47                                 dev = entry->dev;
  48                                 break;
  49                         }
  50                 }
  51
  52                 spin_unlock_irqrestore(&vpci_dev->lock, flags);
  53         }
  54         return dev;
  55 }
  56
  57 static inline int match_slot(struct pci_dev *l, struct pci_dev *r)
  58 {
  59         if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus)
  60             && l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn))
  61                 return 1;
  62
  63         return 0;
  64 }
  65
  66 static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
  67                                    struct pci_dev *dev, int devid,
  68                                    publish_pci_dev_cb publish_cb)
  69 {
  70         int err = 0, slot, func = -1;
  71         struct pci_dev_entry *t, *dev_entry;
  72         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
  73         unsigned long flags;
  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         spin_lock_irqsave(&vpci_dev->lock, flags);
  93
  94         /* Keep multi-function devices together on the virtual PCI bus */
  95         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
  96                 if (!list_empty(&vpci_dev->dev_list[slot])) {
  97                         t = list_entry(list_first(&vpci_dev->dev_list[slot]),
  98                                        struct pci_dev_entry, list);
  99
 100                         if (match_slot(dev, t->dev)) {
 101                                 pr_info(DRV_NAME ": vpci: %s: "
 102                                         "assign to virtual slot %d func %d\n",
 103                                         pci_name(dev), slot,
 104                                         PCI_FUNC(dev->devfn));
 105                                 list_add_tail(&dev_entry->list,
 106                                               &vpci_dev->dev_list[slot]);
 107                                 func = PCI_FUNC(dev->devfn);
 108                                 goto unlock;
 109                         }
 110                 }
 111         }
 112
 113         /* Assign to a new slot on the virtual PCI bus */
 114         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 115                 if (list_empty(&vpci_dev->dev_list[slot])) {
 116                         printk(KERN_INFO DRV_NAME
 117                                ": vpci: %s: assign to virtual slot %d\n",
 118                                pci_name(dev), slot);
 119                         list_add_tail(&dev_entry->list,
 120                                       &vpci_dev->dev_list[slot]);
 121                         func = PCI_FUNC(dev->devfn);
 122                         goto unlock;
 123                 }
 124         }
 125
 126         err = -ENOMEM;
 127         xenbus_dev_fatal(pdev->xdev, err,
 128                          "No more space on root virtual PCI bus");
 129
 130 unlock:
 131         spin_unlock_irqrestore(&vpci_dev->lock, flags);
 132
 133         /* Publish this device. */
 134         if (!err)
 135                 err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid);
 136
 137 out:
 138         return err;
 139 }
 140
 141 static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
 142                                         struct pci_dev *dev)
 143 {
 144         int slot;
 145         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 146         struct pci_dev *found_dev = NULL;
 147         unsigned long flags;
 148
 149         spin_lock_irqsave(&vpci_dev->lock, flags);
 150
 151         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 152                 struct pci_dev_entry *e;
 153
 154                 list_for_each_entry(e, &vpci_dev->dev_list[slot], list) {
 155                         if (e->dev == dev) {
 156                                 list_del(&e->list);
 157                                 found_dev = e->dev;
 158                                 kfree(e);
 159                                 goto out;
 160                         }
 161                 }
 162         }
 163
 164 out:
 165         spin_unlock_irqrestore(&vpci_dev->lock, flags);
 166
 167         if (found_dev)
 168                 pcistub_put_pci_dev(found_dev);
 169 }
 170
 171 static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
 172 {
 173         int slot;
 174         struct vpci_dev_data *vpci_dev;
 175
 176         vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL);
 177         if (!vpci_dev)
 178                 return -ENOMEM;
 179
 180         spin_lock_init(&vpci_dev->lock);
 181
 182         for (slot = 0; slot < PCI_SLOT_MAX; slot++)
 183                 INIT_LIST_HEAD(&vpci_dev->dev_list[slot]);
 184
 185         pdev->pci_dev_data = vpci_dev;
 186
 187         return 0;
 188 }
 189
 190 static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
 191                                          publish_pci_root_cb publish_cb)
 192 {
 193         /* The Virtual PCI bus has only one root */
 194         return publish_cb(pdev, 0, 0);
 195 }
 196
 197 static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
 198 {
 199         int slot;
 200         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 201
 202         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 203                 struct pci_dev_entry *e, *tmp;
 204                 list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
 205                                          list) {
 206                         list_del(&e->list);
 207                         pcistub_put_pci_dev(e->dev);
 208                         kfree(e);
 209                 }
 210         }
 211
 212         kfree(vpci_dev);
 213         pdev->pci_dev_data = NULL;
 214 }
 215
 216 static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
 217                                         struct xen_pcibk_device *pdev,
 218                                         unsigned int *domain, unsigned int *bus,
 219                                         unsigned int *devfn)
 220 {
 221         struct pci_dev_entry *entry;
 222         struct pci_dev *dev = NULL;
 223         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 224         unsigned long flags;
 225         int found = 0, slot;
 226
 227         spin_lock_irqsave(&vpci_dev->lock, flags);
 228         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 229                 list_for_each_entry(entry,
 230                             &vpci_dev->dev_list[slot],
 231                             list) {
 232                         dev = entry->dev;
 233                         if (dev && dev->bus->number == pcidev->bus->number
 234                                 && pci_domain_nr(dev->bus) ==
 235                                         pci_domain_nr(pcidev->bus)
 236                                 && dev->devfn == pcidev->devfn) {
 237                                 found = 1;
 238                                 *domain = 0;
 239                                 *bus = 0;
 240                                 *devfn = PCI_DEVFN(slot,
 241                                          PCI_FUNC(pcidev->devfn));
 242                         }
 243                 }
 244         }
 245         spin_unlock_irqrestore(&vpci_dev->lock, flags);
 246         return found;
 247 }
 248
 249 const struct xen_pcibk_backend xen_pcibk_vpci_backend = {
 250         .name           = "vpci",
 251         .init           = __xen_pcibk_init_devices,
 252         .free           = __xen_pcibk_release_devices,
 253         .find           = __xen_pcibk_get_pcifront_dev,
 254         .publish        = __xen_pcibk_publish_pci_roots,
 255         .release        = __xen_pcibk_release_pci_dev,
 256         .add            = __xen_pcibk_add_pci_dev,
 257         .get            = __xen_pcibk_get_pci_dev,
 258 };