2 * PCI Backend Xenbus Setup - handles setup with frontend and xend
4 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
6 #include <linux/module.h>
7 #include <linux/init.h>
8 #include <linux/list.h>
9 #include <linux/vmalloc.h>
10 #include <linux/workqueue.h>
11 #include <xen/xenbus.h>
12 #include <xen/events.h>
13 #include <asm/xen/pci.h>
16 #define INVALID_EVTCHN_IRQ (-1)
17 struct workqueue_struct *xen_pcibk_wq;
19 static bool __read_mostly passthrough;
20 module_param(passthrough, bool, S_IRUGO);
21 MODULE_PARM_DESC(passthrough,
22 "Option to specify how to export PCI topology to guest:\n"\
23 " 0 - (default) Hide the true PCI topology and makes the frontend\n"\
24 " there is a single PCI bus with only the exported devices on it.\n"\
25 " For example, a device at 03:05.0 will be re-assigned to 00:00.0\n"\
26 " while second device at 02:1a.1 will be re-assigned to 00:01.1.\n"\
27 " 1 - Passthrough provides a real view of the PCI topology to the\n"\
28 " frontend (for example, a device at 06:01.b will still appear at\n"\
29 " 06:01.b to the frontend). This is similar to how Xen 2.0.x\n"\
30 " exposed PCI devices to its driver domains. This may be required\n"\
31 " for drivers which depend on finding their hardward in certain\n"\
32 " bus/slot locations.");
34 static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev)
36 struct xen_pcibk_device *pdev;
38 pdev = kzalloc(sizeof(struct xen_pcibk_device), GFP_KERNEL);
41 dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev);
44 dev_set_drvdata(&xdev->dev, pdev);
46 mutex_init(&pdev->dev_lock);
49 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
50 pdev->be_watching = 0;
52 INIT_WORK(&pdev->op_work, xen_pcibk_do_op);
54 if (xen_pcibk_init_devices(pdev)) {
62 static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
64 mutex_lock(&pdev->dev_lock);
65 /* Ensure the guest can't trigger our handler before removing devices */
66 if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
67 unbind_from_irqhandler(pdev->evtchn_irq, pdev);
68 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
71 /* If the driver domain started an op, make sure we complete it
72 * before releasing the shared memory */
74 /* Note, the workqueue does not use spinlocks at all.*/
75 flush_workqueue(xen_pcibk_wq);
77 if (pdev->sh_info != NULL) {
78 xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
81 mutex_unlock(&pdev->dev_lock);
84 static void free_pdev(struct xen_pcibk_device *pdev)
86 if (pdev->be_watching) {
87 unregister_xenbus_watch(&pdev->be_watch);
88 pdev->be_watching = 0;
91 xen_pcibk_disconnect(pdev);
93 xen_pcibk_release_devices(pdev);
95 dev_set_drvdata(&pdev->xdev->dev, NULL);
101 static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
107 dev_dbg(&pdev->xdev->dev,
108 "Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
109 gnt_ref, remote_evtchn);
111 err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
113 xenbus_dev_fatal(pdev->xdev, err,
114 "Error mapping other domain page in ours.");
118 pdev->sh_info = vaddr;
120 err = bind_interdomain_evtchn_to_irqhandler(
121 pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
124 xenbus_dev_fatal(pdev->xdev, err,
125 "Error binding event channel to IRQ");
128 pdev->evtchn_irq = err;
131 dev_dbg(&pdev->xdev->dev, "Attached!\n");
136 static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
139 int gnt_ref, remote_evtchn;
143 mutex_lock(&pdev->dev_lock);
144 /* Make sure we only do this setup once */
145 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
146 XenbusStateInitialised)
149 /* Wait for frontend to state that it has published the configuration */
150 if (xenbus_read_driver_state(pdev->xdev->otherend) !=
151 XenbusStateInitialised)
154 dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");
156 err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
157 "pci-op-ref", "%u", &gnt_ref,
158 "event-channel", "%u", &remote_evtchn,
159 "magic", NULL, &magic, NULL);
161 /* If configuration didn't get read correctly, wait longer */
162 xenbus_dev_fatal(pdev->xdev, err,
163 "Error reading configuration from frontend");
167 if (magic == NULL || strcmp(magic, XEN_PCI_MAGIC) != 0) {
168 xenbus_dev_fatal(pdev->xdev, -EFAULT,
169 "version mismatch (%s/%s) with pcifront - "
171 magic, XEN_PCI_MAGIC);
175 err = xen_pcibk_do_attach(pdev, gnt_ref, remote_evtchn);
179 dev_dbg(&pdev->xdev->dev, "Connecting...\n");
181 err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
183 xenbus_dev_fatal(pdev->xdev, err,
184 "Error switching to connected state!");
186 dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
188 mutex_unlock(&pdev->dev_lock);
195 static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
196 unsigned int domain, unsigned int bus,
197 unsigned int devfn, unsigned int devid)
203 len = snprintf(str, sizeof(str), "vdev-%d", devid);
204 if (unlikely(len >= (sizeof(str) - 1))) {
209 /* Note: The PV protocol uses %02x, don't change it */
210 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
211 "%04x:%02x:%02x.%02x", domain, bus,
212 PCI_SLOT(devfn), PCI_FUNC(devfn));
218 static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
219 int domain, int bus, int slot, int func,
225 dev_dbg(&pdev->xdev->dev, "exporting dom %x bus %x slot %x func %x\n",
226 domain, bus, slot, func);
228 dev = pcistub_get_pci_dev_by_slot(pdev, domain, bus, slot, func);
231 xenbus_dev_fatal(pdev->xdev, err,
232 "Couldn't locate PCI device "
233 "(%04x:%02x:%02x.%d)! "
234 "perhaps already in-use?",
235 domain, bus, slot, func);
239 err = xen_pcibk_add_pci_dev(pdev, dev, devid,
240 xen_pcibk_publish_pci_dev);
244 dev_dbg(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
245 if (xen_register_device_domain_owner(dev,
246 pdev->xdev->otherend_id) != 0) {
247 dev_err(&dev->dev, "Stealing ownership from dom%d.\n",
248 xen_find_device_domain_owner(dev));
249 xen_unregister_device_domain_owner(dev);
250 xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
253 /* TODO: It'd be nice to export a bridge and have all of its children
254 * get exported with it. This may be best done in xend (which will
255 * have to calculate resource usage anyway) but we probably want to
256 * put something in here to ensure that if a bridge gets given to a
257 * driver domain, that all devices under that bridge are not given
258 * to other driver domains (as he who controls the bridge can disable
259 * it and stop the other devices from working).
265 static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
266 int domain, int bus, int slot, int func)
271 dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
272 domain, bus, slot, func);
274 dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
277 dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
278 "(%04x:%02x:%02x.%d)! not owned by this domain\n",
279 domain, bus, slot, func);
283 dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
284 xen_unregister_device_domain_owner(dev);
286 xen_pcibk_release_pci_dev(pdev, dev);
292 static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
293 unsigned int domain, unsigned int bus)
296 int i, root_num, len, err;
299 dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");
301 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
302 "root_num", "%d", &root_num);
303 if (err == 0 || err == -ENOENT)
308 /* Verify that we haven't already published this pci root */
309 for (i = 0; i < root_num; i++) {
310 len = snprintf(str, sizeof(str), "root-%d", i);
311 if (unlikely(len >= (sizeof(str) - 1))) {
316 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
317 str, "%x:%x", &d, &b);
325 if (d == domain && b == bus) {
331 len = snprintf(str, sizeof(str), "root-%d", root_num);
332 if (unlikely(len >= (sizeof(str) - 1))) {
337 dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
338 root_num, domain, bus);
340 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
341 "%04x:%02x", domain, bus);
345 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
346 "root_num", "%d", (root_num + 1));
352 static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
356 int domain, bus, slot, func;
363 dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
365 mutex_lock(&pdev->dev_lock);
366 /* Make sure we only reconfigure once */
367 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
368 XenbusStateReconfiguring)
371 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
376 xenbus_dev_fatal(pdev->xdev, err,
377 "Error reading number of devices");
381 for (i = 0; i < num_devs; i++) {
382 len = snprintf(state_str, sizeof(state_str), "state-%d", i);
383 if (unlikely(len >= (sizeof(state_str) - 1))) {
385 xenbus_dev_fatal(pdev->xdev, err,
386 "String overflow while reading "
390 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
393 substate = XenbusStateUnknown;
396 case XenbusStateInitialising:
397 dev_dbg(&pdev->xdev->dev, "Attaching dev-%d ...\n", i);
399 len = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
400 if (unlikely(len >= (sizeof(dev_str) - 1))) {
402 xenbus_dev_fatal(pdev->xdev, err,
403 "String overflow while "
404 "reading configuration");
407 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
408 dev_str, "%x:%x:%x.%x",
409 &domain, &bus, &slot, &func);
411 xenbus_dev_fatal(pdev->xdev, err,
412 "Error reading device "
418 xenbus_dev_fatal(pdev->xdev, err,
419 "Error parsing pci device "
424 err = xen_pcibk_export_device(pdev, domain, bus, slot,
429 /* Publish pci roots. */
430 err = xen_pcibk_publish_pci_roots(pdev,
431 xen_pcibk_publish_pci_root);
433 xenbus_dev_fatal(pdev->xdev, err,
434 "Error while publish PCI root"
435 "buses for frontend");
439 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
441 XenbusStateInitialised);
443 xenbus_dev_fatal(pdev->xdev, err,
444 "Error switching substate of "
450 case XenbusStateClosing:
451 dev_dbg(&pdev->xdev->dev, "Detaching dev-%d ...\n", i);
453 len = snprintf(dev_str, sizeof(dev_str), "vdev-%d", i);
454 if (unlikely(len >= (sizeof(dev_str) - 1))) {
456 xenbus_dev_fatal(pdev->xdev, err,
457 "String overflow while "
458 "reading configuration");
461 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
462 dev_str, "%x:%x:%x.%x",
463 &domain, &bus, &slot, &func);
465 xenbus_dev_fatal(pdev->xdev, err,
466 "Error reading device "
472 xenbus_dev_fatal(pdev->xdev, err,
473 "Error parsing pci device "
478 err = xen_pcibk_remove_device(pdev, domain, bus, slot,
483 /* TODO: If at some point we implement support for pci
484 * root hot-remove on pcifront side, we'll need to
485 * remove unnecessary xenstore nodes of pci roots here.
495 err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
497 xenbus_dev_fatal(pdev->xdev, err,
498 "Error switching to reconfigured state!");
503 mutex_unlock(&pdev->dev_lock);
507 static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
508 enum xenbus_state fe_state)
510 struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);
512 dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);
515 case XenbusStateInitialised:
516 xen_pcibk_attach(pdev);
519 case XenbusStateReconfiguring:
520 xen_pcibk_reconfigure(pdev);
523 case XenbusStateConnected:
524 /* pcifront switched its state from reconfiguring to connected.
525 * Then switch to connected state.
527 xenbus_switch_state(xdev, XenbusStateConnected);
530 case XenbusStateClosing:
531 xen_pcibk_disconnect(pdev);
532 xenbus_switch_state(xdev, XenbusStateClosing);
535 case XenbusStateClosed:
536 xen_pcibk_disconnect(pdev);
537 xenbus_switch_state(xdev, XenbusStateClosed);
538 if (xenbus_dev_is_online(xdev))
540 /* fall through if not online */
541 case XenbusStateUnknown:
542 dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
543 device_unregister(&xdev->dev);
551 static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
553 /* Get configuration from xend (if available now) */
554 int domain, bus, slot, func;
560 mutex_lock(&pdev->dev_lock);
561 /* It's possible we could get the call to setup twice, so make sure
562 * we're not already connected.
564 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
568 dev_dbg(&pdev->xdev->dev, "getting be setup\n");
570 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
575 xenbus_dev_fatal(pdev->xdev, err,
576 "Error reading number of devices");
580 for (i = 0; i < num_devs; i++) {
581 int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
582 if (unlikely(l >= (sizeof(dev_str) - 1))) {
584 xenbus_dev_fatal(pdev->xdev, err,
585 "String overflow while reading "
590 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
591 "%x:%x:%x.%x", &domain, &bus, &slot, &func);
593 xenbus_dev_fatal(pdev->xdev, err,
594 "Error reading device configuration");
599 xenbus_dev_fatal(pdev->xdev, err,
600 "Error parsing pci device "
605 err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
609 /* Switch substate of this device. */
610 l = snprintf(state_str, sizeof(state_str), "state-%d", i);
611 if (unlikely(l >= (sizeof(state_str) - 1))) {
613 xenbus_dev_fatal(pdev->xdev, err,
614 "String overflow while reading "
618 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
619 "%d", XenbusStateInitialised);
621 xenbus_dev_fatal(pdev->xdev, err, "Error switching "
622 "substate of dev-%d\n", i);
627 err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
629 xenbus_dev_fatal(pdev->xdev, err,
630 "Error while publish PCI root buses "
635 err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
637 xenbus_dev_fatal(pdev->xdev, err,
638 "Error switching to initialised state!");
641 mutex_unlock(&pdev->dev_lock);
643 /* see if pcifront is already configured (if not, we'll wait) */
644 xen_pcibk_attach(pdev);
648 static void xen_pcibk_be_watch(struct xenbus_watch *watch,
649 const char **vec, unsigned int len)
651 struct xen_pcibk_device *pdev =
652 container_of(watch, struct xen_pcibk_device, be_watch);
654 switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
655 case XenbusStateInitWait:
656 xen_pcibk_setup_backend(pdev);
664 static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
665 const struct xenbus_device_id *id)
668 struct xen_pcibk_device *pdev = alloc_pdev(dev);
672 xenbus_dev_fatal(dev, err,
673 "Error allocating xen_pcibk_device struct");
677 /* wait for xend to configure us */
678 err = xenbus_switch_state(dev, XenbusStateInitWait);
682 /* watch the backend node for backend configuration information */
683 err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
688 pdev->be_watching = 1;
690 /* We need to force a call to our callback here in case
691 * xend already configured us!
693 xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);
699 static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
701 struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);
709 static const struct xenbus_device_id xen_pcibk_ids[] = {
714 static DEFINE_XENBUS_DRIVER(xen_pcibk, DRV_NAME,
715 .probe = xen_pcibk_xenbus_probe,
716 .remove = xen_pcibk_xenbus_remove,
717 .otherend_changed = xen_pcibk_frontend_changed,
720 const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
722 int __init xen_pcibk_xenbus_register(void)
724 xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
726 printk(KERN_ERR "%s: create"
727 "xen_pciback_workqueue failed\n", __func__);
730 xen_pcibk_backend = &xen_pcibk_vpci_backend;
732 xen_pcibk_backend = &xen_pcibk_passthrough_backend;
733 pr_info(DRV_NAME ": backend is %s\n", xen_pcibk_backend->name);
734 return xenbus_register_backend(&xen_pcibk_driver);
737 void __exit xen_pcibk_xenbus_unregister(void)
739 destroy_workqueue(xen_pcibk_wq);
740 xenbus_unregister_driver(&xen_pcibk_driver);