linux/drivers/pci/xen-pcifront.c
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   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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