2 * PCI Backend Xenbus Setup - handles setup with frontend and xend
4 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 #include <linux/moduleparam.h>
10 #include <linux/init.h>
11 #include <linux/list.h>
12 #include <linux/vmalloc.h>
13 #include <linux/workqueue.h>
14 #include <xen/xenbus.h>
15 #include <xen/events.h>
16 #include <asm/xen/pci.h>
19 #define INVALID_EVTCHN_IRQ (-1)
21 static bool __read_mostly passthrough;
22 module_param(passthrough, bool, S_IRUGO);
23 MODULE_PARM_DESC(passthrough,
24 "Option to specify how to export PCI topology to guest:\n"\
25 " 0 - (default) Hide the true PCI topology and makes the frontend\n"\
26 " there is a single PCI bus with only the exported devices on it.\n"\
27 " For example, a device at 03:05.0 will be re-assigned to 00:00.0\n"\
28 " while second device at 02:1a.1 will be re-assigned to 00:01.1.\n"\
29 " 1 - Passthrough provides a real view of the PCI topology to the\n"\
30 " frontend (for example, a device at 06:01.b will still appear at\n"\
31 " 06:01.b to the frontend). This is similar to how Xen 2.0.x\n"\
32 " exposed PCI devices to its driver domains. This may be required\n"\
33 " for drivers which depend on finding their hardward in certain\n"\
34 " bus/slot locations.");
36 static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev)
38 struct xen_pcibk_device *pdev;
40 pdev = kzalloc(sizeof(struct xen_pcibk_device), GFP_KERNEL);
43 dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev);
47 mutex_init(&pdev->dev_lock);
50 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
51 pdev->be_watching = 0;
53 INIT_WORK(&pdev->op_work, xen_pcibk_do_op);
55 if (xen_pcibk_init_devices(pdev)) {
60 dev_set_drvdata(&xdev->dev, pdev);
66 static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
68 mutex_lock(&pdev->dev_lock);
69 /* Ensure the guest can't trigger our handler before removing devices */
70 if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
71 unbind_from_irqhandler(pdev->evtchn_irq, pdev);
72 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
75 /* If the driver domain started an op, make sure we complete it
76 * before releasing the shared memory */
78 flush_work(&pdev->op_work);
80 if (pdev->sh_info != NULL) {
81 xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
84 mutex_unlock(&pdev->dev_lock);
87 static void free_pdev(struct xen_pcibk_device *pdev)
89 if (pdev->be_watching) {
90 unregister_xenbus_watch(&pdev->be_watch);
91 pdev->be_watching = 0;
94 xen_pcibk_disconnect(pdev);
96 /* N.B. This calls pcistub_put_pci_dev which does the FLR on all
97 * of the PCIe devices. */
98 xen_pcibk_release_devices(pdev);
100 dev_set_drvdata(&pdev->xdev->dev, NULL);
106 static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
112 dev_dbg(&pdev->xdev->dev,
113 "Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
114 gnt_ref, remote_evtchn);
116 err = xenbus_map_ring_valloc(pdev->xdev, &gnt_ref, 1, &vaddr);
118 xenbus_dev_fatal(pdev->xdev, err,
119 "Error mapping other domain page in ours.");
123 pdev->sh_info = vaddr;
125 err = bind_interdomain_evtchn_to_irqhandler(
126 pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
129 xenbus_dev_fatal(pdev->xdev, err,
130 "Error binding event channel to IRQ");
133 pdev->evtchn_irq = err;
136 dev_dbg(&pdev->xdev->dev, "Attached!\n");
141 static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
144 int gnt_ref, remote_evtchn;
148 mutex_lock(&pdev->dev_lock);
149 /* Make sure we only do this setup once */
150 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
151 XenbusStateInitialised)
154 /* Wait for frontend to state that it has published the configuration */
155 if (xenbus_read_driver_state(pdev->xdev->otherend) !=
156 XenbusStateInitialised)
159 dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");
161 err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
162 "pci-op-ref", "%u", &gnt_ref,
163 "event-channel", "%u", &remote_evtchn,
164 "magic", NULL, &magic, NULL);
166 /* If configuration didn't get read correctly, wait longer */
167 xenbus_dev_fatal(pdev->xdev, err,
168 "Error reading configuration from frontend");
172 if (magic == NULL || strcmp(magic, XEN_PCI_MAGIC) != 0) {
173 xenbus_dev_fatal(pdev->xdev, -EFAULT,
174 "version mismatch (%s/%s) with pcifront - "
176 magic, XEN_PCI_MAGIC);
181 err = xen_pcibk_do_attach(pdev, gnt_ref, remote_evtchn);
185 dev_dbg(&pdev->xdev->dev, "Connecting...\n");
187 err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
189 xenbus_dev_fatal(pdev->xdev, err,
190 "Error switching to connected state!");
192 dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
194 mutex_unlock(&pdev->dev_lock);
201 static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
202 unsigned int domain, unsigned int bus,
203 unsigned int devfn, unsigned int devid)
209 len = snprintf(str, sizeof(str), "vdev-%d", devid);
210 if (unlikely(len >= (sizeof(str) - 1))) {
215 /* Note: The PV protocol uses %02x, don't change it */
216 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
217 "%04x:%02x:%02x.%02x", domain, bus,
218 PCI_SLOT(devfn), PCI_FUNC(devfn));
224 static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
225 int domain, int bus, int slot, int func,
231 dev_dbg(&pdev->xdev->dev, "exporting dom %x bus %x slot %x func %x\n",
232 domain, bus, slot, func);
234 dev = pcistub_get_pci_dev_by_slot(pdev, domain, bus, slot, func);
237 xenbus_dev_fatal(pdev->xdev, err,
238 "Couldn't locate PCI device "
239 "(%04x:%02x:%02x.%d)! "
240 "perhaps already in-use?",
241 domain, bus, slot, func);
245 err = xen_pcibk_add_pci_dev(pdev, dev, devid,
246 xen_pcibk_publish_pci_dev);
250 dev_info(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
251 if (xen_register_device_domain_owner(dev,
252 pdev->xdev->otherend_id) != 0) {
253 dev_err(&dev->dev, "Stealing ownership from dom%d.\n",
254 xen_find_device_domain_owner(dev));
255 xen_unregister_device_domain_owner(dev);
256 xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
259 /* TODO: It'd be nice to export a bridge and have all of its children
260 * get exported with it. This may be best done in xend (which will
261 * have to calculate resource usage anyway) but we probably want to
262 * put something in here to ensure that if a bridge gets given to a
263 * driver domain, that all devices under that bridge are not given
264 * to other driver domains (as he who controls the bridge can disable
265 * it and stop the other devices from working).
271 static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
272 int domain, int bus, int slot, int func)
277 dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
278 domain, bus, slot, func);
280 dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
283 dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
284 "(%04x:%02x:%02x.%d)! not owned by this domain\n",
285 domain, bus, slot, func);
289 dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
290 xen_unregister_device_domain_owner(dev);
292 /* N.B. This ends up calling pcistub_put_pci_dev which ends up
294 xen_pcibk_release_pci_dev(pdev, dev, true /* use the lock. */);
300 static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
301 unsigned int domain, unsigned int bus)
304 int i, root_num, len, err;
307 dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");
309 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
310 "root_num", "%d", &root_num);
311 if (err == 0 || err == -ENOENT)
316 /* Verify that we haven't already published this pci root */
317 for (i = 0; i < root_num; i++) {
318 len = snprintf(str, sizeof(str), "root-%d", i);
319 if (unlikely(len >= (sizeof(str) - 1))) {
324 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
325 str, "%x:%x", &d, &b);
333 if (d == domain && b == bus) {
339 len = snprintf(str, sizeof(str), "root-%d", root_num);
340 if (unlikely(len >= (sizeof(str) - 1))) {
345 dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
346 root_num, domain, bus);
348 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
349 "%04x:%02x", domain, bus);
353 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
354 "root_num", "%d", (root_num + 1));
360 static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
364 int domain, bus, slot, func;
365 unsigned int substate;
371 dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
373 mutex_lock(&pdev->dev_lock);
374 /* Make sure we only reconfigure once */
375 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
376 XenbusStateReconfiguring)
379 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
384 xenbus_dev_fatal(pdev->xdev, err,
385 "Error reading number of devices");
389 for (i = 0; i < num_devs; i++) {
390 len = snprintf(state_str, sizeof(state_str), "state-%d", i);
391 if (unlikely(len >= (sizeof(state_str) - 1))) {
393 xenbus_dev_fatal(pdev->xdev, err,
394 "String overflow while reading "
398 substate = xenbus_read_unsigned(pdev->xdev->nodename, state_str,
402 case XenbusStateInitialising:
403 dev_dbg(&pdev->xdev->dev, "Attaching dev-%d ...\n", i);
405 len = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
406 if (unlikely(len >= (sizeof(dev_str) - 1))) {
408 xenbus_dev_fatal(pdev->xdev, err,
409 "String overflow while "
410 "reading configuration");
413 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
414 dev_str, "%x:%x:%x.%x",
415 &domain, &bus, &slot, &func);
417 xenbus_dev_fatal(pdev->xdev, err,
418 "Error reading device "
424 xenbus_dev_fatal(pdev->xdev, err,
425 "Error parsing pci device "
430 err = xen_pcibk_export_device(pdev, domain, bus, slot,
435 /* Publish pci roots. */
436 err = xen_pcibk_publish_pci_roots(pdev,
437 xen_pcibk_publish_pci_root);
439 xenbus_dev_fatal(pdev->xdev, err,
440 "Error while publish PCI root"
441 "buses for frontend");
445 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
447 XenbusStateInitialised);
449 xenbus_dev_fatal(pdev->xdev, err,
450 "Error switching substate of "
456 case XenbusStateClosing:
457 dev_dbg(&pdev->xdev->dev, "Detaching dev-%d ...\n", i);
459 len = snprintf(dev_str, sizeof(dev_str), "vdev-%d", i);
460 if (unlikely(len >= (sizeof(dev_str) - 1))) {
462 xenbus_dev_fatal(pdev->xdev, err,
463 "String overflow while "
464 "reading configuration");
467 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
468 dev_str, "%x:%x:%x.%x",
469 &domain, &bus, &slot, &func);
471 xenbus_dev_fatal(pdev->xdev, err,
472 "Error reading device "
478 xenbus_dev_fatal(pdev->xdev, err,
479 "Error parsing pci device "
484 err = xen_pcibk_remove_device(pdev, domain, bus, slot,
489 /* TODO: If at some point we implement support for pci
490 * root hot-remove on pcifront side, we'll need to
491 * remove unnecessary xenstore nodes of pci roots here.
501 err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
503 xenbus_dev_fatal(pdev->xdev, err,
504 "Error switching to reconfigured state!");
509 mutex_unlock(&pdev->dev_lock);
513 static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
514 enum xenbus_state fe_state)
516 struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);
518 dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);
521 case XenbusStateInitialised:
522 xen_pcibk_attach(pdev);
525 case XenbusStateReconfiguring:
526 xen_pcibk_reconfigure(pdev);
529 case XenbusStateConnected:
530 /* pcifront switched its state from reconfiguring to connected.
531 * Then switch to connected state.
533 xenbus_switch_state(xdev, XenbusStateConnected);
536 case XenbusStateClosing:
537 xen_pcibk_disconnect(pdev);
538 xenbus_switch_state(xdev, XenbusStateClosing);
541 case XenbusStateClosed:
542 xen_pcibk_disconnect(pdev);
543 xenbus_switch_state(xdev, XenbusStateClosed);
544 if (xenbus_dev_is_online(xdev))
546 /* fall through if not online */
547 case XenbusStateUnknown:
548 dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
549 device_unregister(&xdev->dev);
557 static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
559 /* Get configuration from xend (if available now) */
560 int domain, bus, slot, func;
566 mutex_lock(&pdev->dev_lock);
567 /* It's possible we could get the call to setup twice, so make sure
568 * we're not already connected.
570 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
574 dev_dbg(&pdev->xdev->dev, "getting be setup\n");
576 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
581 xenbus_dev_fatal(pdev->xdev, err,
582 "Error reading number of devices");
586 for (i = 0; i < num_devs; i++) {
587 int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
588 if (unlikely(l >= (sizeof(dev_str) - 1))) {
590 xenbus_dev_fatal(pdev->xdev, err,
591 "String overflow while reading "
596 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
597 "%x:%x:%x.%x", &domain, &bus, &slot, &func);
599 xenbus_dev_fatal(pdev->xdev, err,
600 "Error reading device configuration");
605 xenbus_dev_fatal(pdev->xdev, err,
606 "Error parsing pci device "
611 err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
615 /* Switch substate of this device. */
616 l = snprintf(state_str, sizeof(state_str), "state-%d", i);
617 if (unlikely(l >= (sizeof(state_str) - 1))) {
619 xenbus_dev_fatal(pdev->xdev, err,
620 "String overflow while reading "
624 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
625 "%d", XenbusStateInitialised);
627 xenbus_dev_fatal(pdev->xdev, err, "Error switching "
628 "substate of dev-%d\n", i);
633 err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
635 xenbus_dev_fatal(pdev->xdev, err,
636 "Error while publish PCI root buses "
641 err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
643 xenbus_dev_fatal(pdev->xdev, err,
644 "Error switching to initialised state!");
647 mutex_unlock(&pdev->dev_lock);
649 /* see if pcifront is already configured (if not, we'll wait) */
650 xen_pcibk_attach(pdev);
654 static void xen_pcibk_be_watch(struct xenbus_watch *watch,
655 const char *path, const char *token)
657 struct xen_pcibk_device *pdev =
658 container_of(watch, struct xen_pcibk_device, be_watch);
660 switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
661 case XenbusStateInitWait:
662 xen_pcibk_setup_backend(pdev);
670 static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
671 const struct xenbus_device_id *id)
674 struct xen_pcibk_device *pdev = alloc_pdev(dev);
678 xenbus_dev_fatal(dev, err,
679 "Error allocating xen_pcibk_device struct");
683 /* wait for xend to configure us */
684 err = xenbus_switch_state(dev, XenbusStateInitWait);
688 /* watch the backend node for backend configuration information */
689 err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
694 pdev->be_watching = 1;
696 /* We need to force a call to our callback here in case
697 * xend already configured us!
699 xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);
705 static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
707 struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);
715 static const struct xenbus_device_id xen_pcibk_ids[] = {
720 static struct xenbus_driver xen_pcibk_driver = {
722 .ids = xen_pcibk_ids,
723 .probe = xen_pcibk_xenbus_probe,
724 .remove = xen_pcibk_xenbus_remove,
725 .otherend_changed = xen_pcibk_frontend_changed,
728 const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
730 int __init xen_pcibk_xenbus_register(void)
732 xen_pcibk_backend = &xen_pcibk_vpci_backend;
734 xen_pcibk_backend = &xen_pcibk_passthrough_backend;
735 pr_info("backend is %s\n", xen_pcibk_backend->name);
736 return xenbus_register_backend(&xen_pcibk_driver);
739 void __exit xen_pcibk_xenbus_unregister(void)
741 xenbus_unregister_driver(&xen_pcibk_driver);