271 lines
6.2 KiB
C
271 lines
6.2 KiB
C
/*
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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 <hap9@epoch.ncsc.mil>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " 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 = -1;
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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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* virtual functions.
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*/
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if (!dev->is_virtfn) {
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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 (match_slot(dev, t->dev)) {
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pr_info("vpci: %s: assign to virtual slot %d func %d\n",
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pci_name(dev), slot,
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PCI_FUNC(dev->devfn));
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list_add_tail(&dev_entry->list,
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&vpci_dev->dev_list[slot]);
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func = PCI_FUNC(dev->devfn);
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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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pr_info("vpci: %s: assign to virtual slot %d\n",
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pci_name(dev), slot);
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list_add_tail(&dev_entry->list,
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&vpci_dev->dev_list[slot]);
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func = dev->is_virtfn ? 0 : PCI_FUNC(dev->devfn);
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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 pci_dev *dev = NULL;
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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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dev = entry->dev;
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if (dev && dev->bus->number == pcidev->bus->number
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&& pci_domain_nr(dev->bus) ==
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pci_domain_nr(pcidev->bus)
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&& dev->devfn == pcidev->devfn) {
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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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