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/module.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)
20 struct workqueue_struct *xen_pcibk_wq;
22 static bool __read_mostly passthrough;
23 module_param(passthrough, bool, S_IRUGO);
24 MODULE_PARM_DESC(passthrough,
25 "Option to specify how to export PCI topology to guest:\n"\
26 " 0 - (default) Hide the true PCI topology and makes the frontend\n"\
27 " there is a single PCI bus with only the exported devices on it.\n"\
28 " For example, a device at 03:05.0 will be re-assigned to 00:00.0\n"\
29 " while second device at 02:1a.1 will be re-assigned to 00:01.1.\n"\
30 " 1 - Passthrough provides a real view of the PCI topology to the\n"\
31 " frontend (for example, a device at 06:01.b will still appear at\n"\
32 " 06:01.b to the frontend). This is similar to how Xen 2.0.x\n"\
33 " exposed PCI devices to its driver domains. This may be required\n"\
34 " for drivers which depend on finding their hardward in certain\n"\
35 " bus/slot locations.");
37 static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev)
39 struct xen_pcibk_device *pdev;
41 pdev = kzalloc(sizeof(struct xen_pcibk_device), GFP_KERNEL);
44 dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev);
47 dev_set_drvdata(&xdev->dev, pdev);
49 mutex_init(&pdev->dev_lock);
52 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
53 pdev->be_watching = 0;
55 INIT_WORK(&pdev->op_work, xen_pcibk_do_op);
57 if (xen_pcibk_init_devices(pdev)) {
65 static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
67 mutex_lock(&pdev->dev_lock);
68 /* Ensure the guest can't trigger our handler before removing devices */
69 if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
70 unbind_from_irqhandler(pdev->evtchn_irq, pdev);
71 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
74 /* If the driver domain started an op, make sure we complete it
75 * before releasing the shared memory */
77 /* Note, the workqueue does not use spinlocks at all.*/
78 flush_workqueue(xen_pcibk_wq);
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 xen_pcibk_release_devices(pdev);
98 dev_set_drvdata(&pdev->xdev->dev, NULL);
104 static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
110 dev_dbg(&pdev->xdev->dev,
111 "Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
112 gnt_ref, remote_evtchn);
114 err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
116 xenbus_dev_fatal(pdev->xdev, err,
117 "Error mapping other domain page in ours.");
121 pdev->sh_info = vaddr;
123 err = bind_interdomain_evtchn_to_irqhandler(
124 pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
127 xenbus_dev_fatal(pdev->xdev, err,
128 "Error binding event channel to IRQ");
131 pdev->evtchn_irq = err;
134 dev_dbg(&pdev->xdev->dev, "Attached!\n");
139 static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
142 int gnt_ref, remote_evtchn;
146 mutex_lock(&pdev->dev_lock);
147 /* Make sure we only do this setup once */
148 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
149 XenbusStateInitialised)
152 /* Wait for frontend to state that it has published the configuration */
153 if (xenbus_read_driver_state(pdev->xdev->otherend) !=
154 XenbusStateInitialised)
157 dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");
159 err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
160 "pci-op-ref", "%u", &gnt_ref,
161 "event-channel", "%u", &remote_evtchn,
162 "magic", NULL, &magic, NULL);
164 /* If configuration didn't get read correctly, wait longer */
165 xenbus_dev_fatal(pdev->xdev, err,
166 "Error reading configuration from frontend");
170 if (magic == NULL || strcmp(magic, XEN_PCI_MAGIC) != 0) {
171 xenbus_dev_fatal(pdev->xdev, -EFAULT,
172 "version mismatch (%s/%s) with pcifront - "
174 magic, XEN_PCI_MAGIC);
178 err = xen_pcibk_do_attach(pdev, gnt_ref, remote_evtchn);
182 dev_dbg(&pdev->xdev->dev, "Connecting...\n");
184 err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
186 xenbus_dev_fatal(pdev->xdev, err,
187 "Error switching to connected state!");
189 dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
191 mutex_unlock(&pdev->dev_lock);
198 static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
199 unsigned int domain, unsigned int bus,
200 unsigned int devfn, unsigned int devid)
206 len = snprintf(str, sizeof(str), "vdev-%d", devid);
207 if (unlikely(len >= (sizeof(str) - 1))) {
212 /* Note: The PV protocol uses %02x, don't change it */
213 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
214 "%04x:%02x:%02x.%02x", domain, bus,
215 PCI_SLOT(devfn), PCI_FUNC(devfn));
221 static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
222 int domain, int bus, int slot, int func,
228 dev_dbg(&pdev->xdev->dev, "exporting dom %x bus %x slot %x func %x\n",
229 domain, bus, slot, func);
231 dev = pcistub_get_pci_dev_by_slot(pdev, domain, bus, slot, func);
234 xenbus_dev_fatal(pdev->xdev, err,
235 "Couldn't locate PCI device "
236 "(%04x:%02x:%02x.%d)! "
237 "perhaps already in-use?",
238 domain, bus, slot, func);
242 err = xen_pcibk_add_pci_dev(pdev, dev, devid,
243 xen_pcibk_publish_pci_dev);
247 dev_dbg(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
248 if (xen_register_device_domain_owner(dev,
249 pdev->xdev->otherend_id) != 0) {
250 dev_err(&dev->dev, "Stealing ownership from dom%d.\n",
251 xen_find_device_domain_owner(dev));
252 xen_unregister_device_domain_owner(dev);
253 xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
256 /* TODO: It'd be nice to export a bridge and have all of its children
257 * get exported with it. This may be best done in xend (which will
258 * have to calculate resource usage anyway) but we probably want to
259 * put something in here to ensure that if a bridge gets given to a
260 * driver domain, that all devices under that bridge are not given
261 * to other driver domains (as he who controls the bridge can disable
262 * it and stop the other devices from working).
268 static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
269 int domain, int bus, int slot, int func)
274 dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
275 domain, bus, slot, func);
277 dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
280 dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
281 "(%04x:%02x:%02x.%d)! not owned by this domain\n",
282 domain, bus, slot, func);
286 dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
287 xen_unregister_device_domain_owner(dev);
289 xen_pcibk_release_pci_dev(pdev, dev);
295 static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
296 unsigned int domain, unsigned int bus)
299 int i, root_num, len, err;
302 dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");
304 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
305 "root_num", "%d", &root_num);
306 if (err == 0 || err == -ENOENT)
311 /* Verify that we haven't already published this pci root */
312 for (i = 0; i < root_num; i++) {
313 len = snprintf(str, sizeof(str), "root-%d", i);
314 if (unlikely(len >= (sizeof(str) - 1))) {
319 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
320 str, "%x:%x", &d, &b);
328 if (d == domain && b == bus) {
334 len = snprintf(str, sizeof(str), "root-%d", root_num);
335 if (unlikely(len >= (sizeof(str) - 1))) {
340 dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
341 root_num, domain, bus);
343 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
344 "%04x:%02x", domain, bus);
348 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
349 "root_num", "%d", (root_num + 1));
355 static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
359 int domain, bus, slot, func;
366 dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
368 mutex_lock(&pdev->dev_lock);
369 /* Make sure we only reconfigure once */
370 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
371 XenbusStateReconfiguring)
374 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
379 xenbus_dev_fatal(pdev->xdev, err,
380 "Error reading number of devices");
384 for (i = 0; i < num_devs; i++) {
385 len = snprintf(state_str, sizeof(state_str), "state-%d", i);
386 if (unlikely(len >= (sizeof(state_str) - 1))) {
388 xenbus_dev_fatal(pdev->xdev, err,
389 "String overflow while reading "
393 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
396 substate = XenbusStateUnknown;
399 case XenbusStateInitialising:
400 dev_dbg(&pdev->xdev->dev, "Attaching dev-%d ...\n", i);
402 len = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
403 if (unlikely(len >= (sizeof(dev_str) - 1))) {
405 xenbus_dev_fatal(pdev->xdev, err,
406 "String overflow while "
407 "reading configuration");
410 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
411 dev_str, "%x:%x:%x.%x",
412 &domain, &bus, &slot, &func);
414 xenbus_dev_fatal(pdev->xdev, err,
415 "Error reading device "
421 xenbus_dev_fatal(pdev->xdev, err,
422 "Error parsing pci device "
427 err = xen_pcibk_export_device(pdev, domain, bus, slot,
432 /* Publish pci roots. */
433 err = xen_pcibk_publish_pci_roots(pdev,
434 xen_pcibk_publish_pci_root);
436 xenbus_dev_fatal(pdev->xdev, err,
437 "Error while publish PCI root"
438 "buses for frontend");
442 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
444 XenbusStateInitialised);
446 xenbus_dev_fatal(pdev->xdev, err,
447 "Error switching substate of "
453 case XenbusStateClosing:
454 dev_dbg(&pdev->xdev->dev, "Detaching dev-%d ...\n", i);
456 len = snprintf(dev_str, sizeof(dev_str), "vdev-%d", i);
457 if (unlikely(len >= (sizeof(dev_str) - 1))) {
459 xenbus_dev_fatal(pdev->xdev, err,
460 "String overflow while "
461 "reading configuration");
464 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
465 dev_str, "%x:%x:%x.%x",
466 &domain, &bus, &slot, &func);
468 xenbus_dev_fatal(pdev->xdev, err,
469 "Error reading device "
475 xenbus_dev_fatal(pdev->xdev, err,
476 "Error parsing pci device "
481 err = xen_pcibk_remove_device(pdev, domain, bus, slot,
486 /* TODO: If at some point we implement support for pci
487 * root hot-remove on pcifront side, we'll need to
488 * remove unnecessary xenstore nodes of pci roots here.
498 err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
500 xenbus_dev_fatal(pdev->xdev, err,
501 "Error switching to reconfigured state!");
506 mutex_unlock(&pdev->dev_lock);
510 static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
511 enum xenbus_state fe_state)
513 struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);
515 dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);
518 case XenbusStateInitialised:
519 xen_pcibk_attach(pdev);
522 case XenbusStateReconfiguring:
523 xen_pcibk_reconfigure(pdev);
526 case XenbusStateConnected:
527 /* pcifront switched its state from reconfiguring to connected.
528 * Then switch to connected state.
530 xenbus_switch_state(xdev, XenbusStateConnected);
533 case XenbusStateClosing:
534 xen_pcibk_disconnect(pdev);
535 xenbus_switch_state(xdev, XenbusStateClosing);
538 case XenbusStateClosed:
539 xen_pcibk_disconnect(pdev);
540 xenbus_switch_state(xdev, XenbusStateClosed);
541 if (xenbus_dev_is_online(xdev))
543 /* fall through if not online */
544 case XenbusStateUnknown:
545 dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
546 device_unregister(&xdev->dev);
554 static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
556 /* Get configuration from xend (if available now) */
557 int domain, bus, slot, func;
563 mutex_lock(&pdev->dev_lock);
564 /* It's possible we could get the call to setup twice, so make sure
565 * we're not already connected.
567 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
571 dev_dbg(&pdev->xdev->dev, "getting be setup\n");
573 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
578 xenbus_dev_fatal(pdev->xdev, err,
579 "Error reading number of devices");
583 for (i = 0; i < num_devs; i++) {
584 int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
585 if (unlikely(l >= (sizeof(dev_str) - 1))) {
587 xenbus_dev_fatal(pdev->xdev, err,
588 "String overflow while reading "
593 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
594 "%x:%x:%x.%x", &domain, &bus, &slot, &func);
596 xenbus_dev_fatal(pdev->xdev, err,
597 "Error reading device configuration");
602 xenbus_dev_fatal(pdev->xdev, err,
603 "Error parsing pci device "
608 err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
612 /* Switch substate of this device. */
613 l = snprintf(state_str, sizeof(state_str), "state-%d", i);
614 if (unlikely(l >= (sizeof(state_str) - 1))) {
616 xenbus_dev_fatal(pdev->xdev, err,
617 "String overflow while reading "
621 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
622 "%d", XenbusStateInitialised);
624 xenbus_dev_fatal(pdev->xdev, err, "Error switching "
625 "substate of dev-%d\n", i);
630 err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
632 xenbus_dev_fatal(pdev->xdev, err,
633 "Error while publish PCI root buses "
638 err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
640 xenbus_dev_fatal(pdev->xdev, err,
641 "Error switching to initialised state!");
644 mutex_unlock(&pdev->dev_lock);
646 /* see if pcifront is already configured (if not, we'll wait) */
647 xen_pcibk_attach(pdev);
651 static void xen_pcibk_be_watch(struct xenbus_watch *watch,
652 const char **vec, unsigned int len)
654 struct xen_pcibk_device *pdev =
655 container_of(watch, struct xen_pcibk_device, be_watch);
657 switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
658 case XenbusStateInitWait:
659 xen_pcibk_setup_backend(pdev);
667 static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
668 const struct xenbus_device_id *id)
671 struct xen_pcibk_device *pdev = alloc_pdev(dev);
675 xenbus_dev_fatal(dev, err,
676 "Error allocating xen_pcibk_device struct");
680 /* wait for xend to configure us */
681 err = xenbus_switch_state(dev, XenbusStateInitWait);
685 /* watch the backend node for backend configuration information */
686 err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
691 pdev->be_watching = 1;
693 /* We need to force a call to our callback here in case
694 * xend already configured us!
696 xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);
702 static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
704 struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);
712 static const struct xenbus_device_id xen_pcibk_ids[] = {
717 static DEFINE_XENBUS_DRIVER(xen_pcibk, DRV_NAME,
718 .probe = xen_pcibk_xenbus_probe,
719 .remove = xen_pcibk_xenbus_remove,
720 .otherend_changed = xen_pcibk_frontend_changed,
723 const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
725 int __init xen_pcibk_xenbus_register(void)
727 xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
729 pr_err("%s: create xen_pciback_workqueue failed\n", __func__);
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 destroy_workqueue(xen_pcibk_wq);
742 xenbus_unregister_driver(&xen_pcibk_driver);