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/*
* PCI Backend - Provides a Virtual PCI bus (with real devices)
* to the frontend
*
* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
*/
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/spinlock.h>
#include "pciback.h"
#define PCI_SLOT_MAX 32
struct vpci_dev_data {
/* Access to dev_list must be protected by lock */
struct list_head dev_list[PCI_SLOT_MAX];
spinlock_t lock;
};
static inline struct list_head *list_first(struct list_head *head)
{
return head->next;
}
struct pci_dev *pciback_get_pci_dev(struct pciback_device *pdev,
unsigned int domain, unsigned int bus,
unsigned int devfn)
{
struct pci_dev_entry *entry;
struct pci_dev *dev = NULL;
struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
unsigned long flags;
if (domain != 0 || bus != 0)
return NULL;
if (PCI_SLOT(devfn) < PCI_SLOT_MAX) {
spin_lock_irqsave(&vpci_dev->lock, flags);
list_for_each_entry(entry,
&vpci_dev->dev_list[PCI_SLOT(devfn)],
list) {
if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) {
dev = entry->dev;
break;
}
}
spin_unlock_irqrestore(&vpci_dev->lock, flags);
}
return dev;
}
static inline int match_slot(struct pci_dev *l, struct pci_dev *r)
{
if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus)
&& l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn))
return 1;
return 0;
}
int pciback_add_pci_dev(struct pciback_device *pdev, struct pci_dev *dev,
int devid, publish_pci_dev_cb publish_cb)
{
int err = 0, slot, func = -1;
struct pci_dev_entry *t, *dev_entry;
struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
unsigned long flags;
if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) {
err = -EFAULT;
xenbus_dev_fatal(pdev->xdev, err,
"Can't export bridges on the virtual PCI bus");
goto out;
}
dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
if (!dev_entry) {
err = -ENOMEM;
xenbus_dev_fatal(pdev->xdev, err,
"Error adding entry to virtual PCI bus");
goto out;
}
dev_entry->dev = dev;
spin_lock_irqsave(&vpci_dev->lock, flags);
/* Keep multi-function devices together on the virtual PCI bus */
for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
if (!list_empty(&vpci_dev->dev_list[slot])) {
t = list_entry(list_first(&vpci_dev->dev_list[slot]),
struct pci_dev_entry, list);
if (match_slot(dev, t->dev)) {
pr_info("pciback: vpci: %s: "
"assign to virtual slot %d func %d\n",
pci_name(dev), slot,
PCI_FUNC(dev->devfn));
list_add_tail(&dev_entry->list,
&vpci_dev->dev_list[slot]);
func = PCI_FUNC(dev->devfn);
goto unlock;
}
}
}
/* Assign to a new slot on the virtual PCI bus */
for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
if (list_empty(&vpci_dev->dev_list[slot])) {
printk(KERN_INFO
"pciback: vpci: %s: assign to virtual slot %d\n",
pci_name(dev), slot);
list_add_tail(&dev_entry->list,
&vpci_dev->dev_list[slot]);
func = PCI_FUNC(dev->devfn);
goto unlock;
}
}
err = -ENOMEM;
xenbus_dev_fatal(pdev->xdev, err,
"No more space on root virtual PCI bus");
unlock:
spin_unlock_irqrestore(&vpci_dev->lock, flags);
/* Publish this device. */
if (!err)
err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid);
out:
return err;
}
void pciback_release_pci_dev(struct pciback_device *pdev, struct pci_dev *dev)
{
int slot;
struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
struct pci_dev *found_dev = NULL;
unsigned long flags;
spin_lock_irqsave(&vpci_dev->lock, flags);
for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
struct pci_dev_entry *e, *tmp;
list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
list) {
if (e->dev == dev) {
list_del(&e->list);
found_dev = e->dev;
kfree(e);
goto out;
}
}
}
out:
spin_unlock_irqrestore(&vpci_dev->lock, flags);
if (found_dev)
pcistub_put_pci_dev(found_dev);
}
int pciback_init_devices(struct pciback_device *pdev)
{
int slot;
struct vpci_dev_data *vpci_dev;
vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL);
if (!vpci_dev)
return -ENOMEM;
spin_lock_init(&vpci_dev->lock);
for (slot = 0; slot < PCI_SLOT_MAX; slot++)
INIT_LIST_HEAD(&vpci_dev->dev_list[slot]);
pdev->pci_dev_data = vpci_dev;
return 0;
}
int pciback_publish_pci_roots(struct pciback_device *pdev,
publish_pci_root_cb publish_cb)
{
/* The Virtual PCI bus has only one root */
return publish_cb(pdev, 0, 0);
}
void pciback_release_devices(struct pciback_device *pdev)
{
int slot;
struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
struct pci_dev_entry *e, *tmp;
list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
list) {
list_del(&e->list);
pcistub_put_pci_dev(e->dev);
kfree(e);
}
}
kfree(vpci_dev);
pdev->pci_dev_data = NULL;
}
int pciback_get_pcifront_dev(struct pci_dev *pcidev,
struct pciback_device *pdev,
unsigned int *domain, unsigned int *bus,
unsigned int *devfn)
{
struct pci_dev_entry *entry;
struct pci_dev *dev = NULL;
struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
unsigned long flags;
int found = 0, slot;
spin_lock_irqsave(&vpci_dev->lock, flags);
for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
list_for_each_entry(entry,
&vpci_dev->dev_list[slot],
list) {
dev = entry->dev;
if (dev && dev->bus->number == pcidev->bus->number
&& pci_domain_nr(dev->bus) ==
pci_domain_nr(pcidev->bus)
&& dev->devfn == pcidev->devfn) {
found = 1;
*domain = 0;
*bus = 0;
*devfn = PCI_DEVFN(slot,
PCI_FUNC(pcidev->devfn));
}
}
}
spin_unlock_irqrestore(&vpci_dev->lock, flags);
return found;
}
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