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kernel/linux-rt-4.4.41/drivers/xen/xen-pciback/passthrough.c 4.74 KB
5113f6f70   김현기   kernel add
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  /*
   * 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,
  };