Root/drivers/pci/xen-pcifront.c

1/*
2 * Xen PCI Frontend.
3 *
4 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
5 */
6#include <linux/module.h>
7#include <linux/init.h>
8#include <linux/mm.h>
9#include <xen/xenbus.h>
10#include <xen/events.h>
11#include <xen/grant_table.h>
12#include <xen/page.h>
13#include <linux/spinlock.h>
14#include <linux/pci.h>
15#include <linux/msi.h>
16#include <xen/interface/io/pciif.h>
17#include <asm/xen/pci.h>
18#include <linux/interrupt.h>
19#include <linux/atomic.h>
20#include <linux/workqueue.h>
21#include <linux/bitops.h>
22#include <linux/time.h>
23
24#define INVALID_GRANT_REF (0)
25#define INVALID_EVTCHN (-1)
26
27struct pci_bus_entry {
28    struct list_head list;
29    struct pci_bus *bus;
30};
31
32#define _PDEVB_op_active (0)
33#define PDEVB_op_active (1 << (_PDEVB_op_active))
34
35struct pcifront_device {
36    struct xenbus_device *xdev;
37    struct list_head root_buses;
38
39    int evtchn;
40    int gnt_ref;
41
42    int irq;
43
44    /* Lock this when doing any operations in sh_info */
45    spinlock_t sh_info_lock;
46    struct xen_pci_sharedinfo *sh_info;
47    struct work_struct op_work;
48    unsigned long flags;
49
50};
51
52struct pcifront_sd {
53    int domain;
54    struct pcifront_device *pdev;
55};
56
57static inline struct pcifront_device *
58pcifront_get_pdev(struct pcifront_sd *sd)
59{
60    return sd->pdev;
61}
62
63static inline void pcifront_init_sd(struct pcifront_sd *sd,
64                    unsigned int domain, unsigned int bus,
65                    struct pcifront_device *pdev)
66{
67    sd->domain = domain;
68    sd->pdev = pdev;
69}
70
71static DEFINE_SPINLOCK(pcifront_dev_lock);
72static struct pcifront_device *pcifront_dev;
73
74static int verbose_request;
75module_param(verbose_request, int, 0644);
76
77static int errno_to_pcibios_err(int errno)
78{
79    switch (errno) {
80    case XEN_PCI_ERR_success:
81        return PCIBIOS_SUCCESSFUL;
82
83    case XEN_PCI_ERR_dev_not_found:
84        return PCIBIOS_DEVICE_NOT_FOUND;
85
86    case XEN_PCI_ERR_invalid_offset:
87    case XEN_PCI_ERR_op_failed:
88        return PCIBIOS_BAD_REGISTER_NUMBER;
89
90    case XEN_PCI_ERR_not_implemented:
91        return PCIBIOS_FUNC_NOT_SUPPORTED;
92
93    case XEN_PCI_ERR_access_denied:
94        return PCIBIOS_SET_FAILED;
95    }
96    return errno;
97}
98
99static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev)
100{
101    if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
102        && !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) {
103        dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n");
104        schedule_work(&pdev->op_work);
105    }
106}
107
108static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
109{
110    int err = 0;
111    struct xen_pci_op *active_op = &pdev->sh_info->op;
112    unsigned long irq_flags;
113    evtchn_port_t port = pdev->evtchn;
114    unsigned irq = pdev->irq;
115    s64 ns, ns_timeout;
116    struct timeval tv;
117
118    spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
119
120    memcpy(active_op, op, sizeof(struct xen_pci_op));
121
122    /* Go */
123    wmb();
124    set_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
125    notify_remote_via_evtchn(port);
126
127    /*
128     * We set a poll timeout of 3 seconds but give up on return after
129     * 2 seconds. It is better to time out too late rather than too early
130     * (in the latter case we end up continually re-executing poll() with a
131     * timeout in the past). 1s difference gives plenty of slack for error.
132     */
133    do_gettimeofday(&tv);
134    ns_timeout = timeval_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;
135
136    xen_clear_irq_pending(irq);
137
138    while (test_bit(_XEN_PCIF_active,
139            (unsigned long *)&pdev->sh_info->flags)) {
140        xen_poll_irq_timeout(irq, jiffies + 3*HZ);
141        xen_clear_irq_pending(irq);
142        do_gettimeofday(&tv);
143        ns = timeval_to_ns(&tv);
144        if (ns > ns_timeout) {
145            dev_err(&pdev->xdev->dev,
146                "pciback not responding!!!\n");
147            clear_bit(_XEN_PCIF_active,
148                  (unsigned long *)&pdev->sh_info->flags);
149            err = XEN_PCI_ERR_dev_not_found;
150            goto out;
151        }
152    }
153
154    /*
155    * We might lose backend service request since we
156    * reuse same evtchn with pci_conf backend response. So re-schedule
157    * aer pcifront service.
158    */
159    if (test_bit(_XEN_PCIB_active,
160            (unsigned long *)&pdev->sh_info->flags)) {
161        dev_err(&pdev->xdev->dev,
162            "schedule aer pcifront service\n");
163        schedule_pcifront_aer_op(pdev);
164    }
165
166    memcpy(op, active_op, sizeof(struct xen_pci_op));
167
168    err = op->err;
169out:
170    spin_unlock_irqrestore(&pdev->sh_info_lock, irq_flags);
171    return err;
172}
173
174/* Access to this function is spinlocked in drivers/pci/access.c */
175static int pcifront_bus_read(struct pci_bus *bus, unsigned int devfn,
176                 int where, int size, u32 *val)
177{
178    int err = 0;
179    struct xen_pci_op op = {
180        .cmd = XEN_PCI_OP_conf_read,
181        .domain = pci_domain_nr(bus),
182        .bus = bus->number,
183        .devfn = devfn,
184        .offset = where,
185        .size = size,
186    };
187    struct pcifront_sd *sd = bus->sysdata;
188    struct pcifront_device *pdev = pcifront_get_pdev(sd);
189
190    if (verbose_request)
191        dev_info(&pdev->xdev->dev,
192             "read dev=%04x:%02x:%02x.%d - offset %x size %d\n",
193             pci_domain_nr(bus), bus->number, PCI_SLOT(devfn),
194             PCI_FUNC(devfn), where, size);
195
196    err = do_pci_op(pdev, &op);
197
198    if (likely(!err)) {
199        if (verbose_request)
200            dev_info(&pdev->xdev->dev, "read got back value %x\n",
201                 op.value);
202
203        *val = op.value;
204    } else if (err == -ENODEV) {
205        /* No device here, pretend that it just returned 0 */
206        err = 0;
207        *val = 0;
208    }
209
210    return errno_to_pcibios_err(err);
211}
212
213/* Access to this function is spinlocked in drivers/pci/access.c */
214static int pcifront_bus_write(struct pci_bus *bus, unsigned int devfn,
215                  int where, int size, u32 val)
216{
217    struct xen_pci_op op = {
218        .cmd = XEN_PCI_OP_conf_write,
219        .domain = pci_domain_nr(bus),
220        .bus = bus->number,
221        .devfn = devfn,
222        .offset = where,
223        .size = size,
224        .value = val,
225    };
226    struct pcifront_sd *sd = bus->sysdata;
227    struct pcifront_device *pdev = pcifront_get_pdev(sd);
228
229    if (verbose_request)
230        dev_info(&pdev->xdev->dev,
231             "write dev=%04x:%02x:%02x.%d - "
232             "offset %x size %d val %x\n",
233             pci_domain_nr(bus), bus->number,
234             PCI_SLOT(devfn), PCI_FUNC(devfn), where, size, val);
235
236    return errno_to_pcibios_err(do_pci_op(pdev, &op));
237}
238
239struct pci_ops pcifront_bus_ops = {
240    .read = pcifront_bus_read,
241    .write = pcifront_bus_write,
242};
243
244#ifdef CONFIG_PCI_MSI
245static int pci_frontend_enable_msix(struct pci_dev *dev,
246                    int vector[], int nvec)
247{
248    int err;
249    int i;
250    struct xen_pci_op op = {
251        .cmd = XEN_PCI_OP_enable_msix,
252        .domain = pci_domain_nr(dev->bus),
253        .bus = dev->bus->number,
254        .devfn = dev->devfn,
255        .value = nvec,
256    };
257    struct pcifront_sd *sd = dev->bus->sysdata;
258    struct pcifront_device *pdev = pcifront_get_pdev(sd);
259    struct msi_desc *entry;
260
261    if (nvec > SH_INFO_MAX_VEC) {
262        dev_err(&dev->dev, "too much vector for pci frontend: %x."
263                   " Increase SH_INFO_MAX_VEC.\n", nvec);
264        return -EINVAL;
265    }
266
267    i = 0;
268    list_for_each_entry(entry, &dev->msi_list, list) {
269        op.msix_entries[i].entry = entry->msi_attrib.entry_nr;
270        /* Vector is useless at this point. */
271        op.msix_entries[i].vector = -1;
272        i++;
273    }
274
275    err = do_pci_op(pdev, &op);
276
277    if (likely(!err)) {
278        if (likely(!op.value)) {
279            /* we get the result */
280            for (i = 0; i < nvec; i++) {
281                if (op.msix_entries[i].vector <= 0) {
282                    dev_warn(&dev->dev, "MSI-X entry %d is invalid: %d!\n",
283                        i, op.msix_entries[i].vector);
284                    err = -EINVAL;
285                    vector[i] = -1;
286                    continue;
287                }
288                vector[i] = op.msix_entries[i].vector;
289            }
290        } else {
291            printk(KERN_DEBUG "enable msix get value %x\n",
292                op.value);
293            err = op.value;
294        }
295    } else {
296        dev_err(&dev->dev, "enable msix get err %x\n", err);
297    }
298    return err;
299}
300
301static void pci_frontend_disable_msix(struct pci_dev *dev)
302{
303    int err;
304    struct xen_pci_op op = {
305        .cmd = XEN_PCI_OP_disable_msix,
306        .domain = pci_domain_nr(dev->bus),
307        .bus = dev->bus->number,
308        .devfn = dev->devfn,
309    };
310    struct pcifront_sd *sd = dev->bus->sysdata;
311    struct pcifront_device *pdev = pcifront_get_pdev(sd);
312
313    err = do_pci_op(pdev, &op);
314
315    /* What should do for error ? */
316    if (err)
317        dev_err(&dev->dev, "pci_disable_msix get err %x\n", err);
318}
319
320static int pci_frontend_enable_msi(struct pci_dev *dev, int vector[])
321{
322    int err;
323    struct xen_pci_op op = {
324        .cmd = XEN_PCI_OP_enable_msi,
325        .domain = pci_domain_nr(dev->bus),
326        .bus = dev->bus->number,
327        .devfn = dev->devfn,
328    };
329    struct pcifront_sd *sd = dev->bus->sysdata;
330    struct pcifront_device *pdev = pcifront_get_pdev(sd);
331
332    err = do_pci_op(pdev, &op);
333    if (likely(!err)) {
334        vector[0] = op.value;
335        if (op.value <= 0) {
336            dev_warn(&dev->dev, "MSI entry is invalid: %d!\n",
337                op.value);
338            err = -EINVAL;
339            vector[0] = -1;
340        }
341    } else {
342        dev_err(&dev->dev, "pci frontend enable msi failed for dev "
343                    "%x:%x\n", op.bus, op.devfn);
344        err = -EINVAL;
345    }
346    return err;
347}
348
349static void pci_frontend_disable_msi(struct pci_dev *dev)
350{
351    int err;
352    struct xen_pci_op op = {
353        .cmd = XEN_PCI_OP_disable_msi,
354        .domain = pci_domain_nr(dev->bus),
355        .bus = dev->bus->number,
356        .devfn = dev->devfn,
357    };
358    struct pcifront_sd *sd = dev->bus->sysdata;
359    struct pcifront_device *pdev = pcifront_get_pdev(sd);
360
361    err = do_pci_op(pdev, &op);
362    if (err == XEN_PCI_ERR_dev_not_found) {
363        /* XXX No response from backend, what shall we do? */
364        printk(KERN_DEBUG "get no response from backend for disable MSI\n");
365        return;
366    }
367    if (err)
368        /* how can pciback notify us fail? */
369        printk(KERN_DEBUG "get fake response frombackend\n");
370}
371
372static struct xen_pci_frontend_ops pci_frontend_ops = {
373    .enable_msi = pci_frontend_enable_msi,
374    .disable_msi = pci_frontend_disable_msi,
375    .enable_msix = pci_frontend_enable_msix,
376    .disable_msix = pci_frontend_disable_msix,
377};
378
379static void pci_frontend_registrar(int enable)
380{
381    if (enable)
382        xen_pci_frontend = &pci_frontend_ops;
383    else
384        xen_pci_frontend = NULL;
385};
386#else
387static inline void pci_frontend_registrar(int enable) { };
388#endif /* CONFIG_PCI_MSI */
389
390/* Claim resources for the PCI frontend as-is, backend won't allow changes */
391static int pcifront_claim_resource(struct pci_dev *dev, void *data)
392{
393    struct pcifront_device *pdev = data;
394    int i;
395    struct resource *r;
396
397    for (i = 0; i < PCI_NUM_RESOURCES; i++) {
398        r = &dev->resource[i];
399
400        if (!r->parent && r->start && r->flags) {
401            dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n",
402                pci_name(dev), i);
403            if (pci_claim_resource(dev, i)) {
404                dev_err(&pdev->xdev->dev, "Could not claim resource %s/%d! "
405                    "Device offline. Try using e820_host=1 in the guest config.\n",
406                    pci_name(dev), i);
407            }
408        }
409    }
410
411    return 0;
412}
413
414static int __devinit pcifront_scan_bus(struct pcifront_device *pdev,
415                unsigned int domain, unsigned int bus,
416                struct pci_bus *b)
417{
418    struct pci_dev *d;
419    unsigned int devfn;
420
421    /* Scan the bus for functions and add.
422     * We omit handling of PCI bridge attachment because pciback prevents
423     * bridges from being exported.
424     */
425    for (devfn = 0; devfn < 0x100; devfn++) {
426        d = pci_get_slot(b, devfn);
427        if (d) {
428            /* Device is already known. */
429            pci_dev_put(d);
430            continue;
431        }
432
433        d = pci_scan_single_device(b, devfn);
434        if (d)
435            dev_info(&pdev->xdev->dev, "New device on "
436                 "%04x:%02x:%02x.%d found.\n", domain, bus,
437                 PCI_SLOT(devfn), PCI_FUNC(devfn));
438    }
439
440    return 0;
441}
442
443static int __devinit pcifront_scan_root(struct pcifront_device *pdev,
444                 unsigned int domain, unsigned int bus)
445{
446    struct pci_bus *b;
447    struct pcifront_sd *sd = NULL;
448    struct pci_bus_entry *bus_entry = NULL;
449    int err = 0;
450
451#ifndef CONFIG_PCI_DOMAINS
452    if (domain != 0) {
453        dev_err(&pdev->xdev->dev,
454            "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
455        dev_err(&pdev->xdev->dev,
456            "Please compile with CONFIG_PCI_DOMAINS\n");
457        err = -EINVAL;
458        goto err_out;
459    }
460#endif
461
462    dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n",
463         domain, bus);
464
465    bus_entry = kmalloc(sizeof(*bus_entry), GFP_KERNEL);
466    sd = kmalloc(sizeof(*sd), GFP_KERNEL);
467    if (!bus_entry || !sd) {
468        err = -ENOMEM;
469        goto err_out;
470    }
471    pcifront_init_sd(sd, domain, bus, pdev);
472
473    b = pci_scan_bus_parented(&pdev->xdev->dev, bus,
474                  &pcifront_bus_ops, sd);
475    if (!b) {
476        dev_err(&pdev->xdev->dev,
477            "Error creating PCI Frontend Bus!\n");
478        err = -ENOMEM;
479        goto err_out;
480    }
481
482    bus_entry->bus = b;
483
484    list_add(&bus_entry->list, &pdev->root_buses);
485
486    /* pci_scan_bus_parented skips devices which do not have a have
487    * devfn==0. The pcifront_scan_bus enumerates all devfn. */
488    err = pcifront_scan_bus(pdev, domain, bus, b);
489
490    /* Claim resources before going "live" with our devices */
491    pci_walk_bus(b, pcifront_claim_resource, pdev);
492
493    /* Create SysFS and notify udev of the devices. Aka: "going live" */
494    pci_bus_add_devices(b);
495
496    return err;
497
498err_out:
499    kfree(bus_entry);
500    kfree(sd);
501
502    return err;
503}
504
505static int __devinit pcifront_rescan_root(struct pcifront_device *pdev,
506                   unsigned int domain, unsigned int bus)
507{
508    int err;
509    struct pci_bus *b;
510
511#ifndef CONFIG_PCI_DOMAINS
512    if (domain != 0) {
513        dev_err(&pdev->xdev->dev,
514            "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
515        dev_err(&pdev->xdev->dev,
516            "Please compile with CONFIG_PCI_DOMAINS\n");
517        return -EINVAL;
518    }
519#endif
520
521    dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
522         domain, bus);
523
524    b = pci_find_bus(domain, bus);
525    if (!b)
526        /* If the bus is unknown, create it. */
527        return pcifront_scan_root(pdev, domain, bus);
528
529    err = pcifront_scan_bus(pdev, domain, bus, b);
530
531    /* Claim resources before going "live" with our devices */
532    pci_walk_bus(b, pcifront_claim_resource, pdev);
533
534    /* Create SysFS and notify udev of the devices. Aka: "going live" */
535    pci_bus_add_devices(b);
536
537    return err;
538}
539
540static void free_root_bus_devs(struct pci_bus *bus)
541{
542    struct pci_dev *dev;
543
544    while (!list_empty(&bus->devices)) {
545        dev = container_of(bus->devices.next, struct pci_dev,
546                   bus_list);
547        dev_dbg(&dev->dev, "removing device\n");
548        pci_stop_and_remove_bus_device(dev);
549    }
550}
551
552static void pcifront_free_roots(struct pcifront_device *pdev)
553{
554    struct pci_bus_entry *bus_entry, *t;
555
556    dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n");
557
558    list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) {
559        list_del(&bus_entry->list);
560
561        free_root_bus_devs(bus_entry->bus);
562
563        kfree(bus_entry->bus->sysdata);
564
565        device_unregister(bus_entry->bus->bridge);
566        pci_remove_bus(bus_entry->bus);
567
568        kfree(bus_entry);
569    }
570}
571
572static pci_ers_result_t pcifront_common_process(int cmd,
573                        struct pcifront_device *pdev,
574                        pci_channel_state_t state)
575{
576    pci_ers_result_t result;
577    struct pci_driver *pdrv;
578    int bus = pdev->sh_info->aer_op.bus;
579    int devfn = pdev->sh_info->aer_op.devfn;
580    struct pci_dev *pcidev;
581    int flag = 0;
582
583    dev_dbg(&pdev->xdev->dev,
584        "pcifront AER process: cmd %x (bus:%x, devfn%x)",
585        cmd, bus, devfn);
586    result = PCI_ERS_RESULT_NONE;
587
588    pcidev = pci_get_bus_and_slot(bus, devfn);
589    if (!pcidev || !pcidev->driver) {
590        dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
591        if (pcidev)
592            pci_dev_put(pcidev);
593        return result;
594    }
595    pdrv = pcidev->driver;
596
597    if (pdrv) {
598        if (pdrv->err_handler && pdrv->err_handler->error_detected) {
599            dev_dbg(&pcidev->dev,
600                "trying to call AER service\n");
601            if (pcidev) {
602                flag = 1;
603                switch (cmd) {
604                case XEN_PCI_OP_aer_detected:
605                    result = pdrv->err_handler->
606                         error_detected(pcidev, state);
607                    break;
608                case XEN_PCI_OP_aer_mmio:
609                    result = pdrv->err_handler->
610                         mmio_enabled(pcidev);
611                    break;
612                case XEN_PCI_OP_aer_slotreset:
613                    result = pdrv->err_handler->
614                         slot_reset(pcidev);
615                    break;
616                case XEN_PCI_OP_aer_resume:
617                    pdrv->err_handler->resume(pcidev);
618                    break;
619                default:
620                    dev_err(&pdev->xdev->dev,
621                        "bad request in aer recovery "
622                        "operation!\n");
623
624                }
625            }
626        }
627    }
628    if (!flag)
629        result = PCI_ERS_RESULT_NONE;
630
631    return result;
632}
633
634
635static void pcifront_do_aer(struct work_struct *data)
636{
637    struct pcifront_device *pdev =
638        container_of(data, struct pcifront_device, op_work);
639    int cmd = pdev->sh_info->aer_op.cmd;
640    pci_channel_state_t state =
641        (pci_channel_state_t)pdev->sh_info->aer_op.err;
642
643    /*If a pci_conf op is in progress,
644        we have to wait until it is done before service aer op*/
645    dev_dbg(&pdev->xdev->dev,
646        "pcifront service aer bus %x devfn %x\n",
647        pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn);
648
649    pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state);
650
651    /* Post the operation to the guest. */
652    wmb();
653    clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags);
654    notify_remote_via_evtchn(pdev->evtchn);
655
656    /*in case of we lost an aer request in four lines time_window*/
657    smp_mb__before_clear_bit();
658    clear_bit(_PDEVB_op_active, &pdev->flags);
659    smp_mb__after_clear_bit();
660
661    schedule_pcifront_aer_op(pdev);
662
663}
664
665static irqreturn_t pcifront_handler_aer(int irq, void *dev)
666{
667    struct pcifront_device *pdev = dev;
668    schedule_pcifront_aer_op(pdev);
669    return IRQ_HANDLED;
670}
671static int pcifront_connect(struct pcifront_device *pdev)
672{
673    int err = 0;
674
675    spin_lock(&pcifront_dev_lock);
676
677    if (!pcifront_dev) {
678        dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
679        pcifront_dev = pdev;
680    } else {
681        dev_err(&pdev->xdev->dev, "PCI frontend already installed!\n");
682        err = -EEXIST;
683    }
684
685    spin_unlock(&pcifront_dev_lock);
686
687    return err;
688}
689
690static void pcifront_disconnect(struct pcifront_device *pdev)
691{
692    spin_lock(&pcifront_dev_lock);
693
694    if (pdev == pcifront_dev) {
695        dev_info(&pdev->xdev->dev,
696             "Disconnecting PCI Frontend Buses\n");
697        pcifront_dev = NULL;
698    }
699
700    spin_unlock(&pcifront_dev_lock);
701}
702static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev)
703{
704    struct pcifront_device *pdev;
705
706    pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL);
707    if (pdev == NULL)
708        goto out;
709
710    pdev->sh_info =
711        (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL);
712    if (pdev->sh_info == NULL) {
713        kfree(pdev);
714        pdev = NULL;
715        goto out;
716    }
717    pdev->sh_info->flags = 0;
718
719    /*Flag for registering PV AER handler*/
720    set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags);
721
722    dev_set_drvdata(&xdev->dev, pdev);
723    pdev->xdev = xdev;
724
725    INIT_LIST_HEAD(&pdev->root_buses);
726
727    spin_lock_init(&pdev->sh_info_lock);
728
729    pdev->evtchn = INVALID_EVTCHN;
730    pdev->gnt_ref = INVALID_GRANT_REF;
731    pdev->irq = -1;
732
733    INIT_WORK(&pdev->op_work, pcifront_do_aer);
734
735    dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n",
736        pdev, pdev->sh_info);
737out:
738    return pdev;
739}
740
741static void free_pdev(struct pcifront_device *pdev)
742{
743    dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
744
745    pcifront_free_roots(pdev);
746
747    cancel_work_sync(&pdev->op_work);
748
749    if (pdev->irq >= 0)
750        unbind_from_irqhandler(pdev->irq, pdev);
751
752    if (pdev->evtchn != INVALID_EVTCHN)
753        xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
754
755    if (pdev->gnt_ref != INVALID_GRANT_REF)
756        gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
757                      (unsigned long)pdev->sh_info);
758    else
759        free_page((unsigned long)pdev->sh_info);
760
761    dev_set_drvdata(&pdev->xdev->dev, NULL);
762
763    kfree(pdev);
764}
765
766static int pcifront_publish_info(struct pcifront_device *pdev)
767{
768    int err = 0;
769    struct xenbus_transaction trans;
770
771    err = xenbus_grant_ring(pdev->xdev, virt_to_mfn(pdev->sh_info));
772    if (err < 0)
773        goto out;
774
775    pdev->gnt_ref = err;
776
777    err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
778    if (err)
779        goto out;
780
781    err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer,
782        0, "pcifront", pdev);
783
784    if (err < 0)
785        return err;
786
787    pdev->irq = err;
788
789do_publish:
790    err = xenbus_transaction_start(&trans);
791    if (err) {
792        xenbus_dev_fatal(pdev->xdev, err,
793                 "Error writing configuration for backend "
794                 "(start transaction)");
795        goto out;
796    }
797
798    err = xenbus_printf(trans, pdev->xdev->nodename,
799                "pci-op-ref", "%u", pdev->gnt_ref);
800    if (!err)
801        err = xenbus_printf(trans, pdev->xdev->nodename,
802                    "event-channel", "%u", pdev->evtchn);
803    if (!err)
804        err = xenbus_printf(trans, pdev->xdev->nodename,
805                    "magic", XEN_PCI_MAGIC);
806
807    if (err) {
808        xenbus_transaction_end(trans, 1);
809        xenbus_dev_fatal(pdev->xdev, err,
810                 "Error writing configuration for backend");
811        goto out;
812    } else {
813        err = xenbus_transaction_end(trans, 0);
814        if (err == -EAGAIN)
815            goto do_publish;
816        else if (err) {
817            xenbus_dev_fatal(pdev->xdev, err,
818                     "Error completing transaction "
819                     "for backend");
820            goto out;
821        }
822    }
823
824    xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
825
826    dev_dbg(&pdev->xdev->dev, "publishing successful!\n");
827
828out:
829    return err;
830}
831
832static int __devinit pcifront_try_connect(struct pcifront_device *pdev)
833{
834    int err = -EFAULT;
835    int i, num_roots, len;
836    char str[64];
837    unsigned int domain, bus;
838
839
840    /* Only connect once */
841    if (xenbus_read_driver_state(pdev->xdev->nodename) !=
842        XenbusStateInitialised)
843        goto out;
844
845    err = pcifront_connect(pdev);
846    if (err) {
847        xenbus_dev_fatal(pdev->xdev, err,
848                 "Error connecting PCI Frontend");
849        goto out;
850    }
851
852    err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
853               "root_num", "%d", &num_roots);
854    if (err == -ENOENT) {
855        xenbus_dev_error(pdev->xdev, err,
856                 "No PCI Roots found, trying 0000:00");
857        err = pcifront_scan_root(pdev, 0, 0);
858        num_roots = 0;
859    } else if (err != 1) {
860        if (err == 0)
861            err = -EINVAL;
862        xenbus_dev_fatal(pdev->xdev, err,
863                 "Error reading number of PCI roots");
864        goto out;
865    }
866
867    for (i = 0; i < num_roots; i++) {
868        len = snprintf(str, sizeof(str), "root-%d", i);
869        if (unlikely(len >= (sizeof(str) - 1))) {
870            err = -ENOMEM;
871            goto out;
872        }
873
874        err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
875                   "%x:%x", &domain, &bus);
876        if (err != 2) {
877            if (err >= 0)
878                err = -EINVAL;
879            xenbus_dev_fatal(pdev->xdev, err,
880                     "Error reading PCI root %d", i);
881            goto out;
882        }
883
884        err = pcifront_scan_root(pdev, domain, bus);
885        if (err) {
886            xenbus_dev_fatal(pdev->xdev, err,
887                     "Error scanning PCI root %04x:%02x",
888                     domain, bus);
889            goto out;
890        }
891    }
892
893    err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
894
895out:
896    return err;
897}
898
899static int pcifront_try_disconnect(struct pcifront_device *pdev)
900{
901    int err = 0;
902    enum xenbus_state prev_state;
903
904
905    prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
906
907    if (prev_state >= XenbusStateClosing)
908        goto out;
909
910    if (prev_state == XenbusStateConnected) {
911        pcifront_free_roots(pdev);
912        pcifront_disconnect(pdev);
913    }
914
915    err = xenbus_switch_state(pdev->xdev, XenbusStateClosed);
916
917out:
918
919    return err;
920}
921
922static int __devinit pcifront_attach_devices(struct pcifront_device *pdev)
923{
924    int err = -EFAULT;
925    int i, num_roots, len;
926    unsigned int domain, bus;
927    char str[64];
928
929    if (xenbus_read_driver_state(pdev->xdev->nodename) !=
930        XenbusStateReconfiguring)
931        goto out;
932
933    err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
934               "root_num", "%d", &num_roots);
935    if (err == -ENOENT) {
936        xenbus_dev_error(pdev->xdev, err,
937                 "No PCI Roots found, trying 0000:00");
938        err = pcifront_rescan_root(pdev, 0, 0);
939        num_roots = 0;
940    } else if (err != 1) {
941        if (err == 0)
942            err = -EINVAL;
943        xenbus_dev_fatal(pdev->xdev, err,
944                 "Error reading number of PCI roots");
945        goto out;
946    }
947
948    for (i = 0; i < num_roots; i++) {
949        len = snprintf(str, sizeof(str), "root-%d", i);
950        if (unlikely(len >= (sizeof(str) - 1))) {
951            err = -ENOMEM;
952            goto out;
953        }
954
955        err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
956                   "%x:%x", &domain, &bus);
957        if (err != 2) {
958            if (err >= 0)
959                err = -EINVAL;
960            xenbus_dev_fatal(pdev->xdev, err,
961                     "Error reading PCI root %d", i);
962            goto out;
963        }
964
965        err = pcifront_rescan_root(pdev, domain, bus);
966        if (err) {
967            xenbus_dev_fatal(pdev->xdev, err,
968                     "Error scanning PCI root %04x:%02x",
969                     domain, bus);
970            goto out;
971        }
972    }
973
974    xenbus_switch_state(pdev->xdev, XenbusStateConnected);
975
976out:
977    return err;
978}
979
980static int pcifront_detach_devices(struct pcifront_device *pdev)
981{
982    int err = 0;
983    int i, num_devs;
984    unsigned int domain, bus, slot, func;
985    struct pci_bus *pci_bus;
986    struct pci_dev *pci_dev;
987    char str[64];
988
989    if (xenbus_read_driver_state(pdev->xdev->nodename) !=
990        XenbusStateConnected)
991        goto out;
992
993    err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d",
994               &num_devs);
995    if (err != 1) {
996        if (err >= 0)
997            err = -EINVAL;
998        xenbus_dev_fatal(pdev->xdev, err,
999                 "Error reading number of PCI devices");
1000        goto out;
1001    }
1002
1003    /* Find devices being detached and remove them. */
1004    for (i = 0; i < num_devs; i++) {
1005        int l, state;
1006        l = snprintf(str, sizeof(str), "state-%d", i);
1007        if (unlikely(l >= (sizeof(str) - 1))) {
1008            err = -ENOMEM;
1009            goto out;
1010        }
1011        err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%d",
1012                   &state);
1013        if (err != 1)
1014            state = XenbusStateUnknown;
1015
1016        if (state != XenbusStateClosing)
1017            continue;
1018
1019        /* Remove device. */
1020        l = snprintf(str, sizeof(str), "vdev-%d", i);
1021        if (unlikely(l >= (sizeof(str) - 1))) {
1022            err = -ENOMEM;
1023            goto out;
1024        }
1025        err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
1026                   "%x:%x:%x.%x", &domain, &bus, &slot, &func);
1027        if (err != 4) {
1028            if (err >= 0)
1029                err = -EINVAL;
1030            xenbus_dev_fatal(pdev->xdev, err,
1031                     "Error reading PCI device %d", i);
1032            goto out;
1033        }
1034
1035        pci_bus = pci_find_bus(domain, bus);
1036        if (!pci_bus) {
1037            dev_dbg(&pdev->xdev->dev, "Cannot get bus %04x:%02x\n",
1038                domain, bus);
1039            continue;
1040        }
1041        pci_dev = pci_get_slot(pci_bus, PCI_DEVFN(slot, func));
1042        if (!pci_dev) {
1043            dev_dbg(&pdev->xdev->dev,
1044                "Cannot get PCI device %04x:%02x:%02x.%d\n",
1045                domain, bus, slot, func);
1046            continue;
1047        }
1048        pci_stop_and_remove_bus_device(pci_dev);
1049        pci_dev_put(pci_dev);
1050
1051        dev_dbg(&pdev->xdev->dev,
1052            "PCI device %04x:%02x:%02x.%d removed.\n",
1053            domain, bus, slot, func);
1054    }
1055
1056    err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring);
1057
1058out:
1059    return err;
1060}
1061
1062static void __init_refok pcifront_backend_changed(struct xenbus_device *xdev,
1063                          enum xenbus_state be_state)
1064{
1065    struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1066
1067    switch (be_state) {
1068    case XenbusStateUnknown:
1069    case XenbusStateInitialising:
1070    case XenbusStateInitWait:
1071    case XenbusStateInitialised:
1072    case XenbusStateClosed:
1073        break;
1074
1075    case XenbusStateConnected:
1076        pcifront_try_connect(pdev);
1077        break;
1078
1079    case XenbusStateClosing:
1080        dev_warn(&xdev->dev, "backend going away!\n");
1081        pcifront_try_disconnect(pdev);
1082        break;
1083
1084    case XenbusStateReconfiguring:
1085        pcifront_detach_devices(pdev);
1086        break;
1087
1088    case XenbusStateReconfigured:
1089        pcifront_attach_devices(pdev);
1090        break;
1091    }
1092}
1093
1094static int pcifront_xenbus_probe(struct xenbus_device *xdev,
1095                 const struct xenbus_device_id *id)
1096{
1097    int err = 0;
1098    struct pcifront_device *pdev = alloc_pdev(xdev);
1099
1100    if (pdev == NULL) {
1101        err = -ENOMEM;
1102        xenbus_dev_fatal(xdev, err,
1103                 "Error allocating pcifront_device struct");
1104        goto out;
1105    }
1106
1107    err = pcifront_publish_info(pdev);
1108    if (err)
1109        free_pdev(pdev);
1110
1111out:
1112    return err;
1113}
1114
1115static int pcifront_xenbus_remove(struct xenbus_device *xdev)
1116{
1117    struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1118    if (pdev)
1119        free_pdev(pdev);
1120
1121    return 0;
1122}
1123
1124static const struct xenbus_device_id xenpci_ids[] = {
1125    {"pci"},
1126    {""},
1127};
1128
1129static DEFINE_XENBUS_DRIVER(xenpci, "pcifront",
1130    .probe = pcifront_xenbus_probe,
1131    .remove = pcifront_xenbus_remove,
1132    .otherend_changed = pcifront_backend_changed,
1133);
1134
1135static int __init pcifront_init(void)
1136{
1137    if (!xen_pv_domain() || xen_initial_domain())
1138        return -ENODEV;
1139
1140    pci_frontend_registrar(1 /* enable */);
1141
1142    return xenbus_register_frontend(&xenpci_driver);
1143}
1144
1145static void __exit pcifront_cleanup(void)
1146{
1147    xenbus_unregister_driver(&xenpci_driver);
1148    pci_frontend_registrar(0 /* disable */);
1149}
1150module_init(pcifront_init);
1151module_exit(pcifront_cleanup);
1152
1153MODULE_DESCRIPTION("Xen PCI passthrough frontend.");
1154MODULE_LICENSE("GPL");
1155MODULE_ALIAS("xen:pci");
1156

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