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 #define DRV_NAME        "xen-pciback"
  16
  17 struct vpci_dev_data {
  18         /* Access to dev_list must be protected by lock */
  19         struct list_head dev_list[PCI_SLOT_MAX];
  20         spinlock_t lock;
  21 };
  22
  23 static inline struct list_head *list_first(struct list_head *head)
  24 {
  25         return head->next;
  26 }
  27
  28 static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev,
  29                                                unsigned int domain,
  30                                                unsigned int bus,
  31                                                unsigned int devfn)
  32 {
  33         struct pci_dev_entry *entry;
  34         struct pci_dev *dev = NULL;
  35         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
  36         unsigned long flags;
  37
  38         if (domain != 0 || bus != 0)
  39                 return NULL;
  40
  41         if (PCI_SLOT(devfn) < PCI_SLOT_MAX) {
  42                 spin_lock_irqsave(&vpci_dev->lock, flags);
  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                 spin_unlock_irqrestore(&vpci_dev->lock, flags);
  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         unsigned long flags;
  75
  76         if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) {
  77                 err = -EFAULT;
  78                 xenbus_dev_fatal(pdev->xdev, err,
  79                                  "Can't export bridges on the virtual PCI bus");
  80                 goto out;
  81         }
  82
  83         dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
  84         if (!dev_entry) {
  85                 err = -ENOMEM;
  86                 xenbus_dev_fatal(pdev->xdev, err,
  87                                  "Error adding entry to virtual PCI bus");
  88                 goto out;
  89         }
  90
  91         dev_entry->dev = dev;
  92
  93         spin_lock_irqsave(&vpci_dev->lock, flags);
  94
  95         /* Keep multi-function devices together on the virtual PCI bus */
  96         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
  97                 if (!list_empty(&vpci_dev->dev_list[slot])) {
  98                         t = list_entry(list_first(&vpci_dev->dev_list[slot]),
  99                                        struct pci_dev_entry, list);
 100
 101                         if (match_slot(dev, t->dev)) {
 102                                 pr_info(DRV_NAME ": vpci: %s: "
 103                                         "assign to virtual slot %d func %d\n",
 104                                         pci_name(dev), slot,
 105                                         PCI_FUNC(dev->devfn));
 106                                 list_add_tail(&dev_entry->list,
 107                                               &vpci_dev->dev_list[slot]);
 108                                 func = PCI_FUNC(dev->devfn);
 109                                 goto unlock;
 110                         }
 111                 }
 112         }
 113
 114         /* Assign to a new slot on the virtual PCI bus */
 115         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 116                 if (list_empty(&vpci_dev->dev_list[slot])) {
 117                         printk(KERN_INFO DRV_NAME
 118                                ": vpci: %s: assign to virtual slot %d\n",
 119                                pci_name(dev), slot);
 120                         list_add_tail(&dev_entry->list,
 121                                       &vpci_dev->dev_list[slot]);
 122                         func = PCI_FUNC(dev->devfn);
 123                         goto unlock;
 124                 }
 125         }
 126
 127         err = -ENOMEM;
 128         xenbus_dev_fatal(pdev->xdev, err,
 129                          "No more space on root virtual PCI bus");
 130
 131 unlock:
 132         spin_unlock_irqrestore(&vpci_dev->lock, flags);
 133
 134         /* Publish this device. */
 135         if (!err)
 136                 err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid);
 137
 138 out:
 139         return err;
 140 }
 141
 142 static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
 143                                         struct pci_dev *dev)
 144 {
 145         int slot;
 146         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 147         struct pci_dev *found_dev = NULL;
 148         unsigned long flags;
 149
 150         spin_lock_irqsave(&vpci_dev->lock, flags);
 151
 152         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 153                 struct pci_dev_entry *e, *tmp;
 154                 list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
 155                                          list) {
 156                         if (e->dev == dev) {
 157                                 list_del(&e->list);
 158                                 found_dev = e->dev;
 159                                 kfree(e);
 160                                 goto out;
 161                         }
 162                 }
 163         }
 164
 165 out:
 166         spin_unlock_irqrestore(&vpci_dev->lock, flags);
 167
 168         if (found_dev)
 169                 pcistub_put_pci_dev(found_dev);
 170 }
 171
 172 static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
 173 {
 174         int slot;
 175         struct vpci_dev_data *vpci_dev;
 176
 177         vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL);
 178         if (!vpci_dev)
 179                 return -ENOMEM;
 180
 181         spin_lock_init(&vpci_dev->lock);
 182
 183         for (slot = 0; slot < PCI_SLOT_MAX; slot++)
 184                 INIT_LIST_HEAD(&vpci_dev->dev_list[slot]);
 185
 186         pdev->pci_dev_data = vpci_dev;
 187
 188         return 0;
 189 }
 190
 191 static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
 192                                          publish_pci_root_cb publish_cb)
 193 {
 194         /* The Virtual PCI bus has only one root */
 195         return publish_cb(pdev, 0, 0);
 196 }
 197
 198 static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
 199 {
 200         int slot;
 201         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 202
 203         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 204                 struct pci_dev_entry *e, *tmp;
 205                 list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
 206                                          list) {
 207                         list_del(&e->list);
 208                         pcistub_put_pci_dev(e->dev);
 209                         kfree(e);
 210                 }
 211         }
 212
 213         kfree(vpci_dev);
 214         pdev->pci_dev_data = NULL;
 215 }
 216
 217 static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
 218                                         struct xen_pcibk_device *pdev,
 219                                         unsigned int *domain, unsigned int *bus,
 220                                         unsigned int *devfn)
 221 {
 222         struct pci_dev_entry *entry;
 223         struct pci_dev *dev = NULL;
 224         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 225         unsigned long flags;
 226         int found = 0, slot;
 227
 228         spin_lock_irqsave(&vpci_dev->lock, flags);
 229         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 230                 list_for_each_entry(entry,
 231                             &vpci_dev->dev_list[slot],
 232                             list) {
 233                         dev = entry->dev;
 234                         if (dev && dev->bus->number == pcidev->bus->number
 235                                 && pci_domain_nr(dev->bus) ==
 236                                         pci_domain_nr(pcidev->bus)
 237                                 && dev->devfn == pcidev->devfn) {
 238                                 found = 1;
 239                                 *domain = 0;
 240                                 *bus = 0;
 241                                 *devfn = PCI_DEVFN(slot,
 242                                          PCI_FUNC(pcidev->devfn));
 243                         }
 244                 }
 245         }
 246         spin_unlock_irqrestore(&vpci_dev->lock, flags);
 247         return found;
 248 }
 249
 250 struct xen_pcibk_backend xen_pcibk_vpci_backend = {
 251         .name           = "vpci",
 252         .init           = __xen_pcibk_init_devices,
 253         .free           = __xen_pcibk_release_devices,
 254         .find           = __xen_pcibk_get_pcifront_dev,
 255         .publish        = __xen_pcibk_publish_pci_roots,
 256         .release        = __xen_pcibk_release_pci_dev,
 257         .add            = __xen_pcibk_add_pci_dev,
 258         .get            = __xen_pcibk_get_pci_dev,
 259 };