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// SPDX-License-Identifier: GPL-2.0
/*
* PCI Backend - Provides restricted access to the real PCI bus topology
* to the frontend
*
* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
*/
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/mutex.h>
#include "pciback.h"
struct passthrough_dev_data {
/* Access to dev_list must be protected by lock */
struct list_head dev_list;
struct mutex lock;
};
static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev,
unsigned int domain,
unsigned int bus,
unsigned int devfn)
{
struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
struct pci_dev_entry *dev_entry;
struct pci_dev *dev = NULL;
mutex_lock(&dev_data->lock);
list_for_each_entry(dev_entry, &dev_data->dev_list, list) {
if (domain == (unsigned int)pci_domain_nr(dev_entry->dev->bus)
&& bus == (unsigned int)dev_entry->dev->bus->number
&& devfn == dev_entry->dev->devfn) {
dev = dev_entry->dev;
break;
}
}
mutex_unlock(&dev_data->lock);
return dev;
}
static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
struct pci_dev *dev,
int devid, publish_pci_dev_cb publish_cb)
{
struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
struct pci_dev_entry *dev_entry;
unsigned int domain, bus, devfn;
int err;
dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
if (!dev_entry)
return -ENOMEM;
dev_entry->dev = dev;
mutex_lock(&dev_data->lock);
list_add_tail(&dev_entry->list, &dev_data->dev_list);
mutex_unlock(&dev_data->lock);
/* Publish this device. */
domain = (unsigned int)pci_domain_nr(dev->bus);
bus = (unsigned int)dev->bus->number;
devfn = dev->devfn;
err = publish_cb(pdev, domain, bus, devfn, devid);
return err;
}
static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
struct pci_dev *dev, bool lock)
{
struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
struct pci_dev_entry *dev_entry, *t;
struct pci_dev *found_dev = NULL;
mutex_lock(&dev_data->lock);
list_for_each_entry_safe(dev_entry, t, &dev_data->dev_list, list) {
if (dev_entry->dev == dev) {
list_del(&dev_entry->list);
found_dev = dev_entry->dev;
kfree(dev_entry);
}
}
mutex_unlock(&dev_data->lock);
if (found_dev) {
if (lock)
device_lock(&found_dev->dev);
pcistub_put_pci_dev(found_dev);
if (lock)
device_unlock(&found_dev->dev);
}
}
static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
{
struct passthrough_dev_data *dev_data;
dev_data = kmalloc(sizeof(*dev_data), GFP_KERNEL);
if (!dev_data)
return -ENOMEM;
mutex_init(&dev_data->lock);
INIT_LIST_HEAD(&dev_data->dev_list);
pdev->pci_dev_data = dev_data;
return 0;
}
static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
publish_pci_root_cb publish_root_cb)
{
int err = 0;
struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
struct pci_dev_entry *dev_entry, *e;
struct pci_dev *dev;
int found;
unsigned int domain, bus;
mutex_lock(&dev_data->lock);
list_for_each_entry(dev_entry, &dev_data->dev_list, list) {
/* Only publish this device as a root if none of its
* parent bridges are exported
*/
found = 0;
dev = dev_entry->dev->bus->self;
for (; !found && dev != NULL; dev = dev->bus->self) {
list_for_each_entry(e, &dev_data->dev_list, list) {
if (dev == e->dev) {
found = 1;
break;
}
}
}
domain = (unsigned int)pci_domain_nr(dev_entry->dev->bus);
bus = (unsigned int)dev_entry->dev->bus->number;
if (!found) {
err = publish_root_cb(pdev, domain, bus);
if (err)
break;
}
}
mutex_unlock(&dev_data->lock);
return err;
}
static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
{
struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
struct pci_dev_entry *dev_entry, *t;
list_for_each_entry_safe(dev_entry, t, &dev_data->dev_list, list) {
struct pci_dev *dev = dev_entry->dev;
list_del(&dev_entry->list);
device_lock(&dev->dev);
pcistub_put_pci_dev(dev);
device_unlock(&dev->dev);
kfree(dev_entry);
}
kfree(dev_data);
pdev->pci_dev_data = NULL;
}
static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
struct xen_pcibk_device *pdev,
unsigned int *domain, unsigned int *bus,
unsigned int *devfn)
{
*domain = pci_domain_nr(pcidev->bus);
*bus = pcidev->bus->number;
*devfn = pcidev->devfn;
return 1;
}
const struct xen_pcibk_backend xen_pcibk_passthrough_backend = {
.name = "passthrough",
.init = __xen_pcibk_init_devices,
.free = __xen_pcibk_release_devices,
.find = __xen_pcibk_get_pcifront_dev,
.publish = __xen_pcibk_publish_pci_roots,
.release = __xen_pcibk_release_pci_dev,
.add = __xen_pcibk_add_pci_dev,
.get = __xen_pcibk_get_pci_dev,
};
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