drivers/xen/xen-pciback/xenbus.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  * PCI Backend Xenbus Setup - handles setup with frontend and xend
  *
  *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
  */
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/vmalloc.h>
 #include <linux/workqueue.h>
 #include <xen/xenbus.h>
 #include <xen/events.h>
 #include <asm/xen/pci.h>
 #include "pciback.h"

 #define INVALID_EVTCHN_IRQ  (-1)
 struct workqueue_struct *xen_pcibk_wq;

 static int __read_mostly passthrough;
 module_param(passthrough, bool, S_IRUGO);
 MODULE_PARM_DESC(passthrough,
 	"Option to specify how to export PCI topology to guest:\n"\
 	" 0 - (default) Hide the true PCI topology and makes the frontend\n"\
 	"   there is a single PCI bus with only the exported devices on it.\n"\
 	"   For example, a device at 03:05.0 will be re-assigned to 00:00.0\n"\
 	"   while second device at 02:1a.1 will be re-assigned to 00:01.1.\n"\
 	" 1 - Passthrough provides a real view of the PCI topology to the\n"\
 	"   frontend (for example, a device at 06:01.b will still appear at\n"\
 	"   06:01.b to the frontend). This is similar to how Xen 2.0.x\n"\
 	"   exposed PCI devices to its driver domains. This may be required\n"\
 	"   for drivers which depend on finding their hardward in certain\n"\
 	"   bus/slot locations.");

 static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev)
 {
 	struct xen_pcibk_device *pdev;

 	pdev = kzalloc(sizeof(struct xen_pcibk_device), GFP_KERNEL);
 	if (pdev == NULL)
 		goto out;
 	dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev);

 	pdev->xdev = xdev;
 	dev_set_drvdata(&xdev->dev, pdev);

 	mutex_init(&pdev->dev_lock);

 	pdev->sh_info = NULL;
 	pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
 	pdev->be_watching = 0;

 	INIT_WORK(&pdev->op_work, xen_pcibk_do_op);

 	if (xen_pcibk_init_devices(pdev)) {
 		kfree(pdev);
 		pdev = NULL;
 	}
 out:
 	return pdev;
 }

 static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
 {
 	mutex_lock(&pdev->dev_lock);
 	/* Ensure the guest can't trigger our handler before removing devices */
 	if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
 		unbind_from_irqhandler(pdev->evtchn_irq, pdev);
 		pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
 	}

 	/* If the driver domain started an op, make sure we complete it
 	 * before releasing the shared memory */

 	/* Note, the workqueue does not use spinlocks at all.*/
 	flush_workqueue(xen_pcibk_wq);

 	if (pdev->sh_info != NULL) {
 		xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
 		pdev->sh_info = NULL;
 	}
 	mutex_unlock(&pdev->dev_lock);
 }

 static void free_pdev(struct xen_pcibk_device *pdev)
 {
 	if (pdev->be_watching) {
 		unregister_xenbus_watch(&pdev->be_watch);
 		pdev->be_watching = 0;
 	}

 	xen_pcibk_disconnect(pdev);

 	xen_pcibk_release_devices(pdev);

 	dev_set_drvdata(&pdev->xdev->dev, NULL);
 	pdev->xdev = NULL;

 	kfree(pdev);
 }

 static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
 			     int remote_evtchn)
 {
 	int err = 0;
 	void *vaddr;

 	dev_dbg(&pdev->xdev->dev,
 		"Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
 		gnt_ref, remote_evtchn);

 	err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
 	if (err < 0) {
 		xenbus_dev_fatal(pdev->xdev, err,
 				"Error mapping other domain page in ours.");
 		goto out;
 	}

 	pdev->sh_info = vaddr;

 	err = bind_interdomain_evtchn_to_irqhandler(
 		pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
 		0, DRV_NAME, pdev);
 	if (err < 0) {
 		xenbus_dev_fatal(pdev->xdev, err,
 				 "Error binding event channel to IRQ");
 		goto out;
 	}
 	pdev->evtchn_irq = err;
 	err = 0;

 	dev_dbg(&pdev->xdev->dev, "Attached!\n");
 out:
 	return err;
 }

 static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
 {
 	int err = 0;
 	int gnt_ref, remote_evtchn;
 	char *magic = NULL;


 	mutex_lock(&pdev->dev_lock);
 	/* Make sure we only do this setup once */
 	if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 	    XenbusStateInitialised)
 		goto out;

 	/* Wait for frontend to state that it has published the configuration */
 	if (xenbus_read_driver_state(pdev->xdev->otherend) !=
 	    XenbusStateInitialised)
 		goto out;

 	dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");

 	err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
 			    "pci-op-ref", "%u", &gnt_ref,
 			    "event-channel", "%u", &remote_evtchn,
 			    "magic", NULL, &magic, NULL);
 	if (err) {
 		/* If configuration didn't get read correctly, wait longer */
 		xenbus_dev_fatal(pdev->xdev, err,
 				 "Error reading configuration from frontend");
 		goto out;
 	}

 	if (magic == NULL || strcmp(magic, XEN_PCI_MAGIC) != 0) {
 		xenbus_dev_fatal(pdev->xdev, -EFAULT,
 				 "version mismatch (%s/%s) with pcifront - "
 				 "halting " DRV_NAME,
 				 magic, XEN_PCI_MAGIC);
 		goto out;
 	}

 	err = xen_pcibk_do_attach(pdev, gnt_ref, remote_evtchn);
 	if (err)
 		goto out;

 	dev_dbg(&pdev->xdev->dev, "Connecting...\n");

 	err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 	if (err)
 		xenbus_dev_fatal(pdev->xdev, err,
 				 "Error switching to connected state!");

 	dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
 out:
 	mutex_unlock(&pdev->dev_lock);

 	kfree(magic);

 	return err;
 }

 static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
 				   unsigned int domain, unsigned int bus,
 				   unsigned int devfn, unsigned int devid)
 {
 	int err;
 	int len;
 	char str[64];

 	len = snprintf(str, sizeof(str), "vdev-%d", devid);
 	if (unlikely(len >= (sizeof(str) - 1))) {
 		err = -ENOMEM;
 		goto out;
 	}

 	err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
 			    "%04x:%02x:%02x.%02x", domain, bus,
 			    PCI_SLOT(devfn), PCI_FUNC(devfn));

 out:
 	return err;
 }

 static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
 				 int domain, int bus, int slot, int func,
 				 int devid)
 {
 	struct pci_dev *dev;
 	int err = 0;

 	dev_dbg(&pdev->xdev->dev, "exporting dom %x bus %x slot %x func %x\n",
 		domain, bus, slot, func);

 	dev = pcistub_get_pci_dev_by_slot(pdev, domain, bus, slot, func);
 	if (!dev) {
 		err = -EINVAL;
 		xenbus_dev_fatal(pdev->xdev, err,
 				 "Couldn't locate PCI device "
 				 "(%04x:%02x:%02x.%01x)! "
 				 "perhaps already in-use?",
 				 domain, bus, slot, func);
 		goto out;
 	}

 	err = xen_pcibk_add_pci_dev(pdev, dev, devid,
 				    xen_pcibk_publish_pci_dev);
 	if (err)
 		goto out;

 	dev_dbg(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
 	if (xen_register_device_domain_owner(dev,
 					     pdev->xdev->otherend_id) != 0) {
 		dev_err(&dev->dev, "Stealing ownership from dom%d.\n",
 			xen_find_device_domain_owner(dev));
 		xen_unregister_device_domain_owner(dev);
 		xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
 	}

 	/* TODO: It'd be nice to export a bridge and have all of its children
 	 * get exported with it. This may be best done in xend (which will
 	 * have to calculate resource usage anyway) but we probably want to
 	 * put something in here to ensure that if a bridge gets given to a
 	 * driver domain, that all devices under that bridge are not given
 	 * to other driver domains (as he who controls the bridge can disable
 	 * it and stop the other devices from working).
 	 */
 out:
 	return err;
 }

 static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
 				 int domain, int bus, int slot, int func)
 {
 	int err = 0;
 	struct pci_dev *dev;

 	dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
 		domain, bus, slot, func);

 	dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
 	if (!dev) {
 		err = -EINVAL;
 		dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
 			"(%04x:%02x:%02x.%01x)! not owned by this domain\n",
 			domain, bus, slot, func);
 		goto out;
 	}

 	dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
 	xen_unregister_device_domain_owner(dev);

 	xen_pcibk_release_pci_dev(pdev, dev);

 out:
 	return err;
 }

 static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
 				    unsigned int domain, unsigned int bus)
 {
 	unsigned int d, b;
 	int i, root_num, len, err;
 	char str[64];

 	dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");

 	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 			   "root_num", "%d", &root_num);
 	if (err == 0 || err == -ENOENT)
 		root_num = 0;
 	else if (err < 0)
 		goto out;

 	/* Verify that we haven't already published this pci root */
 	for (i = 0; i < root_num; i++) {
 		len = snprintf(str, sizeof(str), "root-%d", i);
 		if (unlikely(len >= (sizeof(str) - 1))) {
 			err = -ENOMEM;
 			goto out;
 		}

 		err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 				   str, "%x:%x", &d, &b);
 		if (err < 0)
 			goto out;
 		if (err != 2) {
 			err = -EINVAL;
 			goto out;
 		}

 		if (d == domain && b == bus) {
 			err = 0;
 			goto out;
 		}
 	}

 	len = snprintf(str, sizeof(str), "root-%d", root_num);
 	if (unlikely(len >= (sizeof(str) - 1))) {
 		err = -ENOMEM;
 		goto out;
 	}

 	dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
 		root_num, domain, bus);

 	err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
 			    "%04x:%02x", domain, bus);
 	if (err)
 		goto out;

 	err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
 			    "root_num", "%d", (root_num + 1));

 out:
 	return err;
 }

 static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
 {
 	int err = 0;
 	int num_devs;
 	int domain, bus, slot, func;
 	int substate;
 	int i, len;
 	char state_str[64];
 	char dev_str[64];


 	dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");

 	mutex_lock(&pdev->dev_lock);
 	/* Make sure we only reconfigure once */
 	if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 	    XenbusStateReconfiguring)
 		goto out;

 	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
 			   &num_devs);
 	if (err != 1) {
 		if (err >= 0)
 			err = -EINVAL;
 		xenbus_dev_fatal(pdev->xdev, err,
 				 "Error reading number of devices");
 		goto out;
 	}

 	for (i = 0; i < num_devs; i++) {
 		len = snprintf(state_str, sizeof(state_str), "state-%d", i);
 		if (unlikely(len >= (sizeof(state_str) - 1))) {
 			err = -ENOMEM;
 			xenbus_dev_fatal(pdev->xdev, err,
 					 "String overflow while reading "
 					 "configuration");
 			goto out;
 		}
 		err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
 				   "%d", &substate);
 		if (err != 1)
 			substate = XenbusStateUnknown;

 		switch (substate) {
 		case XenbusStateInitialising:
 			dev_dbg(&pdev->xdev->dev, "Attaching dev-%d ...\n", i);

 			len = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
 			if (unlikely(len >= (sizeof(dev_str) - 1))) {
 				err = -ENOMEM;
 				xenbus_dev_fatal(pdev->xdev, err,
 						 "String overflow while "
 						 "reading configuration");
 				goto out;
 			}
 			err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 					   dev_str, "%x:%x:%x.%x",
 					   &domain, &bus, &slot, &func);
 			if (err < 0) {
 				xenbus_dev_fatal(pdev->xdev, err,
 						 "Error reading device "
 						 "configuration");
 				goto out;
 			}
 			if (err != 4) {
 				err = -EINVAL;
 				xenbus_dev_fatal(pdev->xdev, err,
 						 "Error parsing pci device "
 						 "configuration");
 				goto out;
 			}

 			err = xen_pcibk_export_device(pdev, domain, bus, slot,
 						    func, i);
 			if (err)
 				goto out;

 			/* Publish pci roots. */
 			err = xen_pcibk_publish_pci_roots(pdev,
 						xen_pcibk_publish_pci_root);
 			if (err) {
 				xenbus_dev_fatal(pdev->xdev, err,
 						 "Error while publish PCI root"
 						 "buses for frontend");
 				goto out;
 			}

 			err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
 					    state_str, "%d",
 					    XenbusStateInitialised);
 			if (err) {
 				xenbus_dev_fatal(pdev->xdev, err,
 						 "Error switching substate of "
 						 "dev-%d\n", i);
 				goto out;
 			}
 			break;

 		case XenbusStateClosing:
 			dev_dbg(&pdev->xdev->dev, "Detaching dev-%d ...\n", i);

 			len = snprintf(dev_str, sizeof(dev_str), "vdev-%d", i);
 			if (unlikely(len >= (sizeof(dev_str) - 1))) {
 				err = -ENOMEM;
 				xenbus_dev_fatal(pdev->xdev, err,
 						 "String overflow while "
 						 "reading configuration");
 				goto out;
 			}
 			err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 					   dev_str, "%x:%x:%x.%x",
 					   &domain, &bus, &slot, &func);
 			if (err < 0) {
 				xenbus_dev_fatal(pdev->xdev, err,
 						 "Error reading device "
 						 "configuration");
 				goto out;
 			}
 			if (err != 4) {
 				err = -EINVAL;
 				xenbus_dev_fatal(pdev->xdev, err,
 						 "Error parsing pci device "
 						 "configuration");
 				goto out;
 			}

 			err = xen_pcibk_remove_device(pdev, domain, bus, slot,
 						    func);
 			if (err)
 				goto out;

 			/* TODO: If at some point we implement support for pci
 			 * root hot-remove on pcifront side, we'll need to
 			 * remove unnecessary xenstore nodes of pci roots here.
 			 */

 			break;

 		default:
 			break;
 		}
 	}

 	err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
 	if (err) {
 		xenbus_dev_fatal(pdev->xdev, err,
 				 "Error switching to reconfigured state!");
 		goto out;
 	}

 out:
 	mutex_unlock(&pdev->dev_lock);
 	return 0;
 }

 static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
 				     enum xenbus_state fe_state)
 {
 	struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);

 	dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);

 	switch (fe_state) {
 	case XenbusStateInitialised:
 		xen_pcibk_attach(pdev);
 		break;

 	case XenbusStateReconfiguring:
 		xen_pcibk_reconfigure(pdev);
 		break;

 	case XenbusStateConnected:
 		/* pcifront switched its state from reconfiguring to connected.
 		 * Then switch to connected state.
 		 */
 		xenbus_switch_state(xdev, XenbusStateConnected);
 		break;

 	case XenbusStateClosing:
 		xen_pcibk_disconnect(pdev);
 		xenbus_switch_state(xdev, XenbusStateClosing);
 		break;

 	case XenbusStateClosed:
 		xen_pcibk_disconnect(pdev);
 		xenbus_switch_state(xdev, XenbusStateClosed);
 		if (xenbus_dev_is_online(xdev))
 			break;
 		/* fall through if not online */
 	case XenbusStateUnknown:
 		dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
 		device_unregister(&xdev->dev);
 		break;

 	default:
 		break;
 	}
 }

 static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
 {
 	/* Get configuration from xend (if available now) */
 	int domain, bus, slot, func;
 	int err = 0;
 	int i, num_devs;
 	char dev_str[64];
 	char state_str[64];

 	mutex_lock(&pdev->dev_lock);
 	/* It's possible we could get the call to setup twice, so make sure
 	 * we're not already connected.
 	 */
 	if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 	    XenbusStateInitWait)
 		goto out;

 	dev_dbg(&pdev->xdev->dev, "getting be setup\n");

 	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
 			   &num_devs);
 	if (err != 1) {
 		if (err >= 0)
 			err = -EINVAL;
 		xenbus_dev_fatal(pdev->xdev, err,
 				 "Error reading number of devices");
 		goto out;
 	}

 	for (i = 0; i < num_devs; i++) {
 		int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
 		if (unlikely(l >= (sizeof(dev_str) - 1))) {
 			err = -ENOMEM;
 			xenbus_dev_fatal(pdev->xdev, err,
 					 "String overflow while reading "
 					 "configuration");
 			goto out;
 		}

 		err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
 				   "%x:%x:%x.%x", &domain, &bus, &slot, &func);
 		if (err < 0) {
 			xenbus_dev_fatal(pdev->xdev, err,
 					 "Error reading device configuration");
 			goto out;
 		}
 		if (err != 4) {
 			err = -EINVAL;
 			xenbus_dev_fatal(pdev->xdev, err,
 					 "Error parsing pci device "
 					 "configuration");
 			goto out;
 		}

 		err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
 		if (err)
 			goto out;

 		/* Switch substate of this device. */
 		l = snprintf(state_str, sizeof(state_str), "state-%d", i);
 		if (unlikely(l >= (sizeof(state_str) - 1))) {
 			err = -ENOMEM;
 			xenbus_dev_fatal(pdev->xdev, err,
 					 "String overflow while reading "
 					 "configuration");
 			goto out;
 		}
 		err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
 				    "%d", XenbusStateInitialised);
 		if (err) {
 			xenbus_dev_fatal(pdev->xdev, err, "Error switching "
 					 "substate of dev-%d\n", i);
 			goto out;
 		}
 	}

 	err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
 	if (err) {
 		xenbus_dev_fatal(pdev->xdev, err,
 				 "Error while publish PCI root buses "
 				 "for frontend");
 		goto out;
 	}

 	err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
 	if (err)
 		xenbus_dev_fatal(pdev->xdev, err,
 				 "Error switching to initialised state!");

 out:
 	mutex_unlock(&pdev->dev_lock);
 	if (!err)
 		/* see if pcifront is already configured (if not, we'll wait) */
 		xen_pcibk_attach(pdev);
 	return err;
 }

 static void xen_pcibk_be_watch(struct xenbus_watch *watch,
 			     const char **vec, unsigned int len)
 {
 	struct xen_pcibk_device *pdev =
 	    container_of(watch, struct xen_pcibk_device, be_watch);

 	switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
 	case XenbusStateInitWait:
 		xen_pcibk_setup_backend(pdev);
 		break;

 	default:
 		break;
 	}
 }

 static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
 				const struct xenbus_device_id *id)
 {
 	int err = 0;
 	struct xen_pcibk_device *pdev = alloc_pdev(dev);

 	if (pdev == NULL) {
 		err = -ENOMEM;
 		xenbus_dev_fatal(dev, err,
 				 "Error allocating xen_pcibk_device struct");
 		goto out;
 	}

 	/* wait for xend to configure us */
 	err = xenbus_switch_state(dev, XenbusStateInitWait);
 	if (err)
 		goto out;

 	/* watch the backend node for backend configuration information */
 	err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
 				xen_pcibk_be_watch);
 	if (err)
 		goto out;

 	pdev->be_watching = 1;

 	/* We need to force a call to our callback here in case
 	 * xend already configured us!
 	 */
 	xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);

 out:
 	return err;
 }

 static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
 {
 	struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);

 	if (pdev != NULL)
 		free_pdev(pdev);

 	return 0;
 }

 static const struct xenbus_device_id xen_pcibk_ids[] = {
 	{"pci"},
 	{""},
 };

 static DEFINE_XENBUS_DRIVER(xen_pcibk, DRV_NAME,
 	.probe			= xen_pcibk_xenbus_probe,
 	.remove			= xen_pcibk_xenbus_remove,
 	.otherend_changed	= xen_pcibk_frontend_changed,
 );

 const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;

 int __init xen_pcibk_xenbus_register(void)
 {
 	xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
 	if (!xen_pcibk_wq) {
 		printk(KERN_ERR "%s: create"
 			"xen_pciback_workqueue failed\n", __func__);
 		return -EFAULT;
 	}
 	xen_pcibk_backend = &xen_pcibk_vpci_backend;
 	if (passthrough)
 		xen_pcibk_backend = &xen_pcibk_passthrough_backend;
 	pr_info(DRV_NAME ": backend is %s\n", xen_pcibk_backend->name);
 	return xenbus_register_backend(&xen_pcibk_driver);
 }

 void __exit xen_pcibk_xenbus_unregister(void)
 {
 	destroy_workqueue(xen_pcibk_wq);
 	xenbus_unregister_driver(&xen_pcibk_driver);
 }
	/*
	* PCI Backend Xenbus Setup - handles setup with frontend and xend
	*
	* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
	*/
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/list.h>
	#include <linux/vmalloc.h>
	#include <linux/workqueue.h>
	#include <xen/xenbus.h>
	#include <xen/events.h>
	#include <asm/xen/pci.h>
	#include "pciback.h"

	#define INVALID_EVTCHN_IRQ (-1)
	struct workqueue_struct *xen_pcibk_wq;

	static int __read_mostly passthrough;
	module_param(passthrough, bool, S_IRUGO);
	MODULE_PARM_DESC(passthrough,
	"Option to specify how to export PCI topology to guest:\n"\
	" 0 - (default) Hide the true PCI topology and makes the frontend\n"\
	" there is a single PCI bus with only the exported devices on it.\n"\
	" For example, a device at 03:05.0 will be re-assigned to 00:00.0\n"\
	" while second device at 02:1a.1 will be re-assigned to 00:01.1.\n"\
	" 1 - Passthrough provides a real view of the PCI topology to the\n"\
	" frontend (for example, a device at 06:01.b will still appear at\n"\
	" 06:01.b to the frontend). This is similar to how Xen 2.0.x\n"\
	" exposed PCI devices to its driver domains. This may be required\n"\
	" for drivers which depend on finding their hardward in certain\n"\
	" bus/slot locations.");

	static struct xen_pcibk_device alloc_pdev(struct xenbus_device xdev)
	{
	struct xen_pcibk_device *pdev;

	pdev = kzalloc(sizeof(struct xen_pcibk_device), GFP_KERNEL);
	if (pdev == NULL)
	goto out;
	dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev);

	pdev->xdev = xdev;
	dev_set_drvdata(&xdev->dev, pdev);

	mutex_init(&pdev->dev_lock);

	pdev->sh_info = NULL;
	pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
	pdev->be_watching = 0;

	INIT_WORK(&pdev->op_work, xen_pcibk_do_op);

	if (xen_pcibk_init_devices(pdev)) {
	kfree(pdev);
	pdev = NULL;
	}
	out:
	return pdev;
	}

	static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
	{
	mutex_lock(&pdev->dev_lock);
	/* Ensure the guest can't trigger our handler before removing devices */
	if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
	unbind_from_irqhandler(pdev->evtchn_irq, pdev);
	pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
	}

	/* If the driver domain started an op, make sure we complete it
	* before releasing the shared memory */

	/* Note, the workqueue does not use spinlocks at all.*/
	flush_workqueue(xen_pcibk_wq);

	if (pdev->sh_info != NULL) {
	xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
	pdev->sh_info = NULL;
	}
	mutex_unlock(&pdev->dev_lock);
	}

	static void free_pdev(struct xen_pcibk_device *pdev)
	{
	if (pdev->be_watching) {
	unregister_xenbus_watch(&pdev->be_watch);
	pdev->be_watching = 0;
	}

	xen_pcibk_disconnect(pdev);

	xen_pcibk_release_devices(pdev);

	dev_set_drvdata(&pdev->xdev->dev, NULL);
	pdev->xdev = NULL;

	kfree(pdev);
	}

	static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
	int remote_evtchn)
	{
	int err = 0;
	void *vaddr;

	dev_dbg(&pdev->xdev->dev,
	"Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
	gnt_ref, remote_evtchn);

	err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
	if (err < 0) {
	xenbus_dev_fatal(pdev->xdev, err,
	"Error mapping other domain page in ours.");
	goto out;
	}

	pdev->sh_info = vaddr;

	err = bind_interdomain_evtchn_to_irqhandler(
	pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
	0, DRV_NAME, pdev);
	if (err < 0) {
	xenbus_dev_fatal(pdev->xdev, err,
	"Error binding event channel to IRQ");
	goto out;
	}
	pdev->evtchn_irq = err;
	err = 0;

	dev_dbg(&pdev->xdev->dev, "Attached!\n");
	out:
	return err;
	}

	static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
	{
	int err = 0;
	int gnt_ref, remote_evtchn;
	char *magic = NULL;


	mutex_lock(&pdev->dev_lock);
	/* Make sure we only do this setup once */
	if (xenbus_read_driver_state(pdev->xdev->nodename) !=
	XenbusStateInitialised)
	goto out;

	/* Wait for frontend to state that it has published the configuration */
	if (xenbus_read_driver_state(pdev->xdev->otherend) !=
	XenbusStateInitialised)
	goto out;

	dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");

	err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
	"pci-op-ref", "%u", &gnt_ref,
	"event-channel", "%u", &remote_evtchn,
	"magic", NULL, &magic, NULL);
	if (err) {
	/* If configuration didn't get read correctly, wait longer */
	xenbus_dev_fatal(pdev->xdev, err,
	"Error reading configuration from frontend");
	goto out;
	}

	if (magic == NULL \|\| strcmp(magic, XEN_PCI_MAGIC) != 0) {
	xenbus_dev_fatal(pdev->xdev, -EFAULT,
	"version mismatch (%s/%s) with pcifront - "
	"halting " DRV_NAME,
	magic, XEN_PCI_MAGIC);
	goto out;
	}

	err = xen_pcibk_do_attach(pdev, gnt_ref, remote_evtchn);
	if (err)
	goto out;

	dev_dbg(&pdev->xdev->dev, "Connecting...\n");

	err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
	if (err)
	xenbus_dev_fatal(pdev->xdev, err,
	"Error switching to connected state!");

	dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
	out:
	mutex_unlock(&pdev->dev_lock);

	kfree(magic);

	return err;
	}

	static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
	unsigned int domain, unsigned int bus,
	unsigned int devfn, unsigned int devid)
	{
	int err;
	int len;
	char str[64];

	len = snprintf(str, sizeof(str), "vdev-%d", devid);
	if (unlikely(len >= (sizeof(str) - 1))) {
	err = -ENOMEM;
	goto out;
	}

	err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
	"%04x:%02x:%02x.%02x", domain, bus,
	PCI_SLOT(devfn), PCI_FUNC(devfn));

	out:
	return err;
	}

	static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
	int domain, int bus, int slot, int func,
	int devid)
	{
	struct pci_dev *dev;
	int err = 0;

	dev_dbg(&pdev->xdev->dev, "exporting dom %x bus %x slot %x func %x\n",
	domain, bus, slot, func);

	dev = pcistub_get_pci_dev_by_slot(pdev, domain, bus, slot, func);
	if (!dev) {
	err = -EINVAL;
	xenbus_dev_fatal(pdev->xdev, err,
	"Couldn't locate PCI device "
	"(%04x:%02x:%02x.%01x)! "
	"perhaps already in-use?",
	domain, bus, slot, func);
	goto out;
	}

	err = xen_pcibk_add_pci_dev(pdev, dev, devid,
	xen_pcibk_publish_pci_dev);
	if (err)
	goto out;

	dev_dbg(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
	if (xen_register_device_domain_owner(dev,
	pdev->xdev->otherend_id) != 0) {
	dev_err(&dev->dev, "Stealing ownership from dom%d.\n",
	xen_find_device_domain_owner(dev));
	xen_unregister_device_domain_owner(dev);
	xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
	}

	/* TODO: It'd be nice to export a bridge and have all of its children
	* get exported with it. This may be best done in xend (which will
	* have to calculate resource usage anyway) but we probably want to
	* put something in here to ensure that if a bridge gets given to a
	* driver domain, that all devices under that bridge are not given
	* to other driver domains (as he who controls the bridge can disable
	* it and stop the other devices from working).
	*/
	out:
	return err;
	}

	static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
	int domain, int bus, int slot, int func)
	{
	int err = 0;
	struct pci_dev *dev;

	dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
	domain, bus, slot, func);

	dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
	if (!dev) {
	err = -EINVAL;
	dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
	"(%04x:%02x:%02x.%01x)! not owned by this domain\n",
	domain, bus, slot, func);
	goto out;
	}

	dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
	xen_unregister_device_domain_owner(dev);

	xen_pcibk_release_pci_dev(pdev, dev);

	out:
	return err;
	}

	static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
	unsigned int domain, unsigned int bus)
	{
	unsigned int d, b;
	int i, root_num, len, err;
	char str[64];

	dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");

	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
	"root_num", "%d", &root_num);
	if (err == 0 \|\| err == -ENOENT)
	root_num = 0;
	else if (err < 0)
	goto out;

	/* Verify that we haven't already published this pci root */
	for (i = 0; i < root_num; i++) {
	len = snprintf(str, sizeof(str), "root-%d", i);
	if (unlikely(len >= (sizeof(str) - 1))) {
	err = -ENOMEM;
	goto out;
	}

	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
	str, "%x:%x", &d, &b);
	if (err < 0)
	goto out;
	if (err != 2) {
	err = -EINVAL;
	goto out;
	}

	if (d == domain && b == bus) {
	err = 0;
	goto out;
	}
	}

	len = snprintf(str, sizeof(str), "root-%d", root_num);
	if (unlikely(len >= (sizeof(str) - 1))) {
	err = -ENOMEM;
	goto out;
	}

	dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
	root_num, domain, bus);

	err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
	"%04x:%02x", domain, bus);
	if (err)
	goto out;

	err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
	"root_num", "%d", (root_num + 1));

	out:
	return err;
	}

	static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
	{
	int err = 0;
	int num_devs;
	int domain, bus, slot, func;
	int substate;
	int i, len;
	char state_str[64];
	char dev_str[64];


	dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");

	mutex_lock(&pdev->dev_lock);
	/* Make sure we only reconfigure once */
	if (xenbus_read_driver_state(pdev->xdev->nodename) !=
	XenbusStateReconfiguring)
	goto out;

	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
	&num_devs);
	if (err != 1) {
	if (err >= 0)
	err = -EINVAL;
	xenbus_dev_fatal(pdev->xdev, err,
	"Error reading number of devices");
	goto out;
	}

	for (i = 0; i < num_devs; i++) {
	len = snprintf(state_str, sizeof(state_str), "state-%d", i);
	if (unlikely(len >= (sizeof(state_str) - 1))) {
	err = -ENOMEM;
	xenbus_dev_fatal(pdev->xdev, err,
	"String overflow while reading "
	"configuration");
	goto out;
	}
	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
	"%d", &substate);
	if (err != 1)
	substate = XenbusStateUnknown;

	switch (substate) {
	case XenbusStateInitialising:
	dev_dbg(&pdev->xdev->dev, "Attaching dev-%d ...\n", i);

	len = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
	if (unlikely(len >= (sizeof(dev_str) - 1))) {
	err = -ENOMEM;
	xenbus_dev_fatal(pdev->xdev, err,
	"String overflow while "
	"reading configuration");
	goto out;
	}
	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
	dev_str, "%x:%x:%x.%x",
	&domain, &bus, &slot, &func);
	if (err < 0) {
	xenbus_dev_fatal(pdev->xdev, err,
	"Error reading device "
	"configuration");
	goto out;
	}
	if (err != 4) {
	err = -EINVAL;
	xenbus_dev_fatal(pdev->xdev, err,
	"Error parsing pci device "
	"configuration");
	goto out;
	}

	err = xen_pcibk_export_device(pdev, domain, bus, slot,
	func, i);
	if (err)
	goto out;

	/* Publish pci roots. */
	err = xen_pcibk_publish_pci_roots(pdev,
	xen_pcibk_publish_pci_root);
	if (err) {
	xenbus_dev_fatal(pdev->xdev, err,
	"Error while publish PCI root"
	"buses for frontend");
	goto out;
	}

	err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
	state_str, "%d",
	XenbusStateInitialised);
	if (err) {
	xenbus_dev_fatal(pdev->xdev, err,
	"Error switching substate of "
	"dev-%d\n", i);
	goto out;
	}
	break;

	case XenbusStateClosing:
	dev_dbg(&pdev->xdev->dev, "Detaching dev-%d ...\n", i);

	len = snprintf(dev_str, sizeof(dev_str), "vdev-%d", i);
	if (unlikely(len >= (sizeof(dev_str) - 1))) {
	err = -ENOMEM;
	xenbus_dev_fatal(pdev->xdev, err,
	"String overflow while "
	"reading configuration");
	goto out;
	}
	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
	dev_str, "%x:%x:%x.%x",
	&domain, &bus, &slot, &func);
	if (err < 0) {
	xenbus_dev_fatal(pdev->xdev, err,
	"Error reading device "
	"configuration");
	goto out;
	}
	if (err != 4) {
	err = -EINVAL;
	xenbus_dev_fatal(pdev->xdev, err,
	"Error parsing pci device "
	"configuration");
	goto out;
	}

	err = xen_pcibk_remove_device(pdev, domain, bus, slot,
	func);
	if (err)
	goto out;

	/* TODO: If at some point we implement support for pci
	* root hot-remove on pcifront side, we'll need to
	* remove unnecessary xenstore nodes of pci roots here.
	*/

	break;

	default:
	break;
	}
	}

	err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
	if (err) {
	xenbus_dev_fatal(pdev->xdev, err,
	"Error switching to reconfigured state!");
	goto out;
	}

	out:
	mutex_unlock(&pdev->dev_lock);
	return 0;
	}

	static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
	enum xenbus_state fe_state)
	{
	struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);

	dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);

	switch (fe_state) {
	case XenbusStateInitialised:
	xen_pcibk_attach(pdev);
	break;

	case XenbusStateReconfiguring:
	xen_pcibk_reconfigure(pdev);
	break;

	case XenbusStateConnected:
	/* pcifront switched its state from reconfiguring to connected.
	* Then switch to connected state.
	*/
	xenbus_switch_state(xdev, XenbusStateConnected);
	break;

	case XenbusStateClosing:
	xen_pcibk_disconnect(pdev);
	xenbus_switch_state(xdev, XenbusStateClosing);
	break;

	case XenbusStateClosed:
	xen_pcibk_disconnect(pdev);
	xenbus_switch_state(xdev, XenbusStateClosed);
	if (xenbus_dev_is_online(xdev))
	break;
	/* fall through if not online */
	case XenbusStateUnknown:
	dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
	device_unregister(&xdev->dev);
	break;

	default:
	break;
	}
	}

	static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
	{
	/* Get configuration from xend (if available now) */
	int domain, bus, slot, func;
	int err = 0;
	int i, num_devs;
	char dev_str[64];
	char state_str[64];

	mutex_lock(&pdev->dev_lock);
	/* It's possible we could get the call to setup twice, so make sure
	* we're not already connected.
	*/
	if (xenbus_read_driver_state(pdev->xdev->nodename) !=
	XenbusStateInitWait)
	goto out;

	dev_dbg(&pdev->xdev->dev, "getting be setup\n");

	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
	&num_devs);
	if (err != 1) {
	if (err >= 0)
	err = -EINVAL;
	xenbus_dev_fatal(pdev->xdev, err,
	"Error reading number of devices");
	goto out;
	}

	for (i = 0; i < num_devs; i++) {
	int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
	if (unlikely(l >= (sizeof(dev_str) - 1))) {
	err = -ENOMEM;
	xenbus_dev_fatal(pdev->xdev, err,
	"String overflow while reading "
	"configuration");
	goto out;
	}

	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
	"%x:%x:%x.%x", &domain, &bus, &slot, &func);
	if (err < 0) {
	xenbus_dev_fatal(pdev->xdev, err,
	"Error reading device configuration");
	goto out;
	}
	if (err != 4) {
	err = -EINVAL;
	xenbus_dev_fatal(pdev->xdev, err,
	"Error parsing pci device "
	"configuration");
	goto out;
	}

	err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
	if (err)
	goto out;

	/* Switch substate of this device. */
	l = snprintf(state_str, sizeof(state_str), "state-%d", i);
	if (unlikely(l >= (sizeof(state_str) - 1))) {
	err = -ENOMEM;
	xenbus_dev_fatal(pdev->xdev, err,
	"String overflow while reading "
	"configuration");
	goto out;
	}
	err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
	"%d", XenbusStateInitialised);
	if (err) {
	xenbus_dev_fatal(pdev->xdev, err, "Error switching "
	"substate of dev-%d\n", i);
	goto out;
	}
	}

	err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
	if (err) {
	xenbus_dev_fatal(pdev->xdev, err,
	"Error while publish PCI root buses "
	"for frontend");
	goto out;
	}

	err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
	if (err)
	xenbus_dev_fatal(pdev->xdev, err,
	"Error switching to initialised state!");

	out:
	mutex_unlock(&pdev->dev_lock);
	if (!err)
	/* see if pcifront is already configured (if not, we'll wait) */
	xen_pcibk_attach(pdev);
	return err;
	}

	static void xen_pcibk_be_watch(struct xenbus_watch *watch,
	const char **vec, unsigned int len)
	{
	struct xen_pcibk_device *pdev =
	container_of(watch, struct xen_pcibk_device, be_watch);

	switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
	case XenbusStateInitWait:
	xen_pcibk_setup_backend(pdev);
	break;

	default:
	break;
	}
	}

	static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
	const struct xenbus_device_id *id)
	{
	int err = 0;
	struct xen_pcibk_device *pdev = alloc_pdev(dev);

	if (pdev == NULL) {
	err = -ENOMEM;
	xenbus_dev_fatal(dev, err,
	"Error allocating xen_pcibk_device struct");
	goto out;
	}

	/* wait for xend to configure us */
	err = xenbus_switch_state(dev, XenbusStateInitWait);
	if (err)
	goto out;

	/* watch the backend node for backend configuration information */
	err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
	xen_pcibk_be_watch);
	if (err)
	goto out;

	pdev->be_watching = 1;

	/* We need to force a call to our callback here in case
	* xend already configured us!
	*/
	xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);

	out:
	return err;
	}

	static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
	{
	struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);

	if (pdev != NULL)
	free_pdev(pdev);

	return 0;
	}

	static const struct xenbus_device_id xen_pcibk_ids[] = {
	{"pci"},
	{""},
	};

	static DEFINE_XENBUS_DRIVER(xen_pcibk, DRV_NAME,
	.probe = xen_pcibk_xenbus_probe,
	.remove = xen_pcibk_xenbus_remove,
	.otherend_changed = xen_pcibk_frontend_changed,
	);

	const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;

	int __init xen_pcibk_xenbus_register(void)
	{
	xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
	if (!xen_pcibk_wq) {
	printk(KERN_ERR "%s: create"
	"xen_pciback_workqueue failed\n", __func__);
	return -EFAULT;
	}
	xen_pcibk_backend = &xen_pcibk_vpci_backend;
	if (passthrough)
	xen_pcibk_backend = &xen_pcibk_passthrough_backend;
	pr_info(DRV_NAME ": backend is %s\n", xen_pcibk_backend->name);
	return xenbus_register_backend(&xen_pcibk_driver);
	}

	void __exit xen_pcibk_xenbus_unregister(void)
	{
	destroy_workqueue(xen_pcibk_wq);
	xenbus_unregister_driver(&xen_pcibk_driver);
	}