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268 lines
6.2 KiB
268 lines
6.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* PCI Backend - Provides a Virtual PCI bus (with real devices) |
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* to the frontend |
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* |
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* Author: Ryan Wilson <[email protected]> |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#define dev_fmt pr_fmt |
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#include <linux/list.h> |
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#include <linux/slab.h> |
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#include <linux/pci.h> |
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#include <linux/mutex.h> |
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#include "pciback.h" |
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#define PCI_SLOT_MAX 32 |
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struct vpci_dev_data { |
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/* Access to dev_list must be protected by lock */ |
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struct list_head dev_list[PCI_SLOT_MAX]; |
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struct mutex lock; |
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}; |
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static inline struct list_head *list_first(struct list_head *head) |
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{ |
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return head->next; |
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} |
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static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev, |
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unsigned int domain, |
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unsigned int bus, |
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unsigned int devfn) |
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{ |
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struct pci_dev_entry *entry; |
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struct pci_dev *dev = NULL; |
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struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; |
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if (domain != 0 || bus != 0) |
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return NULL; |
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if (PCI_SLOT(devfn) < PCI_SLOT_MAX) { |
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mutex_lock(&vpci_dev->lock); |
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list_for_each_entry(entry, |
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&vpci_dev->dev_list[PCI_SLOT(devfn)], |
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list) { |
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if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) { |
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dev = entry->dev; |
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break; |
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} |
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} |
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mutex_unlock(&vpci_dev->lock); |
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} |
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return dev; |
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} |
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static inline int match_slot(struct pci_dev *l, struct pci_dev *r) |
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{ |
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if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus) |
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&& l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn)) |
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return 1; |
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return 0; |
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} |
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static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev, |
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struct pci_dev *dev, int devid, |
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publish_pci_dev_cb publish_cb) |
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{ |
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int err = 0, slot, func = PCI_FUNC(dev->devfn); |
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struct pci_dev_entry *t, *dev_entry; |
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struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; |
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if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) { |
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err = -EFAULT; |
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xenbus_dev_fatal(pdev->xdev, err, |
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"Can't export bridges on the virtual PCI bus"); |
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goto out; |
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} |
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dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL); |
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if (!dev_entry) { |
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err = -ENOMEM; |
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xenbus_dev_fatal(pdev->xdev, err, |
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"Error adding entry to virtual PCI bus"); |
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goto out; |
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} |
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dev_entry->dev = dev; |
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mutex_lock(&vpci_dev->lock); |
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/* |
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* Keep multi-function devices together on the virtual PCI bus, except |
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* that we want to keep virtual functions at func 0 on their own. They |
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* aren't multi-function devices and hence their presence at func 0 |
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* may cause guests to not scan the other functions. |
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*/ |
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if (!dev->is_virtfn || func) { |
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for (slot = 0; slot < PCI_SLOT_MAX; slot++) { |
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if (list_empty(&vpci_dev->dev_list[slot])) |
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continue; |
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t = list_entry(list_first(&vpci_dev->dev_list[slot]), |
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struct pci_dev_entry, list); |
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if (t->dev->is_virtfn && !PCI_FUNC(t->dev->devfn)) |
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continue; |
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if (match_slot(dev, t->dev)) { |
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dev_info(&dev->dev, "vpci: assign to virtual slot %d func %d\n", |
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slot, func); |
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list_add_tail(&dev_entry->list, |
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&vpci_dev->dev_list[slot]); |
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goto unlock; |
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} |
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} |
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} |
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/* Assign to a new slot on the virtual PCI bus */ |
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for (slot = 0; slot < PCI_SLOT_MAX; slot++) { |
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if (list_empty(&vpci_dev->dev_list[slot])) { |
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dev_info(&dev->dev, "vpci: assign to virtual slot %d\n", |
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slot); |
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list_add_tail(&dev_entry->list, |
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&vpci_dev->dev_list[slot]); |
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goto unlock; |
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} |
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} |
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err = -ENOMEM; |
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xenbus_dev_fatal(pdev->xdev, err, |
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"No more space on root virtual PCI bus"); |
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unlock: |
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mutex_unlock(&vpci_dev->lock); |
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/* Publish this device. */ |
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if (!err) |
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err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid); |
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else |
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kfree(dev_entry); |
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out: |
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return err; |
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} |
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static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev, |
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struct pci_dev *dev, bool lock) |
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{ |
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int slot; |
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struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; |
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struct pci_dev *found_dev = NULL; |
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mutex_lock(&vpci_dev->lock); |
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for (slot = 0; slot < PCI_SLOT_MAX; slot++) { |
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struct pci_dev_entry *e; |
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list_for_each_entry(e, &vpci_dev->dev_list[slot], list) { |
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if (e->dev == dev) { |
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list_del(&e->list); |
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found_dev = e->dev; |
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kfree(e); |
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goto out; |
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} |
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} |
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} |
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out: |
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mutex_unlock(&vpci_dev->lock); |
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if (found_dev) { |
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if (lock) |
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device_lock(&found_dev->dev); |
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pcistub_put_pci_dev(found_dev); |
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if (lock) |
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device_unlock(&found_dev->dev); |
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} |
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} |
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static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev) |
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{ |
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int slot; |
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struct vpci_dev_data *vpci_dev; |
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vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL); |
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if (!vpci_dev) |
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return -ENOMEM; |
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mutex_init(&vpci_dev->lock); |
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for (slot = 0; slot < PCI_SLOT_MAX; slot++) |
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INIT_LIST_HEAD(&vpci_dev->dev_list[slot]); |
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pdev->pci_dev_data = vpci_dev; |
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return 0; |
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} |
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static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev, |
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publish_pci_root_cb publish_cb) |
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{ |
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/* The Virtual PCI bus has only one root */ |
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return publish_cb(pdev, 0, 0); |
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} |
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static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev) |
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{ |
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int slot; |
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struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; |
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for (slot = 0; slot < PCI_SLOT_MAX; slot++) { |
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struct pci_dev_entry *e, *tmp; |
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list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot], |
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list) { |
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struct pci_dev *dev = e->dev; |
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list_del(&e->list); |
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device_lock(&dev->dev); |
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pcistub_put_pci_dev(dev); |
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device_unlock(&dev->dev); |
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kfree(e); |
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} |
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} |
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kfree(vpci_dev); |
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pdev->pci_dev_data = NULL; |
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} |
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static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev, |
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struct xen_pcibk_device *pdev, |
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unsigned int *domain, unsigned int *bus, |
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unsigned int *devfn) |
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{ |
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struct pci_dev_entry *entry; |
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struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; |
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int found = 0, slot; |
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mutex_lock(&vpci_dev->lock); |
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for (slot = 0; slot < PCI_SLOT_MAX; slot++) { |
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list_for_each_entry(entry, |
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&vpci_dev->dev_list[slot], |
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list) { |
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if (entry->dev == pcidev) { |
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found = 1; |
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*domain = 0; |
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*bus = 0; |
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*devfn = PCI_DEVFN(slot, |
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PCI_FUNC(pcidev->devfn)); |
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} |
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} |
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} |
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mutex_unlock(&vpci_dev->lock); |
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return found; |
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} |
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const struct xen_pcibk_backend xen_pcibk_vpci_backend = { |
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.name = "vpci", |
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.init = __xen_pcibk_init_devices, |
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.free = __xen_pcibk_release_devices, |
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.find = __xen_pcibk_get_pcifront_dev, |
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.publish = __xen_pcibk_publish_pci_roots, |
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.release = __xen_pcibk_release_pci_dev, |
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.add = __xen_pcibk_add_pci_dev, |
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.get = __xen_pcibk_get_pci_dev, |
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};
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