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 <asm/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
  27 struct 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
  35 struct 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
  52 struct pcifront_sd {
  53         int domain;
  54         struct pcifront_device *pdev;
  55 };
  56
  57 static inline struct pcifront_device *
  58 pcifront_get_pdev(struct pcifront_sd *sd)
  59 {
  60         return sd->pdev;
  61 }
  62
  63 static 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
  71 static DEFINE_SPINLOCK(pcifront_dev_lock);
  72 static struct pcifront_device *pcifront_dev;
  73
  74 static int verbose_request;
  75 module_param(verbose_request, int, 0644);
  76
  77 static 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
  99 static 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
 108 static 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;
 169 out:
 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 */
 175 static 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.%01x - 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 */
 214 static 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.%01x - "
 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
 239 struct pci_ops pcifront_bus_ops = {
 240         .read = pcifront_bus_read,
 241         .write = pcifront_bus_write,
 242 };
 243
 244 #ifdef CONFIG_PCI_MSI
 245 static 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                                 *(*vector+i) = op.msix_entries[i].vector;
 282                         return 0;
 283                 } else {
 284                         printk(KERN_DEBUG "enable msix get value %x\n",
 285                                 op.value);
 286                         return op.value;
 287                 }
 288         } else {
 289                 dev_err(&dev->dev, "enable msix get err %x\n", err);
 290                 return err;
 291         }
 292 }
 293
 294 static void pci_frontend_disable_msix(struct pci_dev *dev)
 295 {
 296         int err;
 297         struct xen_pci_op op = {
 298                 .cmd    = XEN_PCI_OP_disable_msix,
 299                 .domain = pci_domain_nr(dev->bus),
 300                 .bus = dev->bus->number,
 301                 .devfn = dev->devfn,
 302         };
 303         struct pcifront_sd *sd = dev->bus->sysdata;
 304         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 305
 306         err = do_pci_op(pdev, &op);
 307
 308         /* What should do for error ? */
 309         if (err)
 310                 dev_err(&dev->dev, "pci_disable_msix get err %x\n", err);
 311 }
 312
 313 static int pci_frontend_enable_msi(struct pci_dev *dev, int **vector)
 314 {
 315         int err;
 316         struct xen_pci_op op = {
 317                 .cmd    = XEN_PCI_OP_enable_msi,
 318                 .domain = pci_domain_nr(dev->bus),
 319                 .bus = dev->bus->number,
 320                 .devfn = dev->devfn,
 321         };
 322         struct pcifront_sd *sd = dev->bus->sysdata;
 323         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 324
 325         err = do_pci_op(pdev, &op);
 326         if (likely(!err)) {
 327                 *(*vector) = op.value;
 328         } else {
 329                 dev_err(&dev->dev, "pci frontend enable msi failed for dev "
 330                                     "%x:%x\n", op.bus, op.devfn);
 331                 err = -EINVAL;
 332         }
 333         return err;
 334 }
 335
 336 static void pci_frontend_disable_msi(struct pci_dev *dev)
 337 {
 338         int err;
 339         struct xen_pci_op op = {
 340                 .cmd    = XEN_PCI_OP_disable_msi,
 341                 .domain = pci_domain_nr(dev->bus),
 342                 .bus = dev->bus->number,
 343                 .devfn = dev->devfn,
 344         };
 345         struct pcifront_sd *sd = dev->bus->sysdata;
 346         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 347
 348         err = do_pci_op(pdev, &op);
 349         if (err == XEN_PCI_ERR_dev_not_found) {
 350                 /* XXX No response from backend, what shall we do? */
 351                 printk(KERN_DEBUG "get no response from backend for disable MSI\n");
 352                 return;
 353         }
 354         if (err)
 355                 /* how can pciback notify us fail? */
 356                 printk(KERN_DEBUG "get fake response frombackend\n");
 357 }
 358
 359 static struct xen_pci_frontend_ops pci_frontend_ops = {
 360         .enable_msi = pci_frontend_enable_msi,
 361         .disable_msi = pci_frontend_disable_msi,
 362         .enable_msix = pci_frontend_enable_msix,
 363         .disable_msix = pci_frontend_disable_msix,
 364 };
 365
 366 static void pci_frontend_registrar(int enable)
 367 {
 368         if (enable)
 369                 xen_pci_frontend = &pci_frontend_ops;
 370         else
 371                 xen_pci_frontend = NULL;
 372 };
 373 #else
 374 static inline void pci_frontend_registrar(int enable) { };
 375 #endif /* CONFIG_PCI_MSI */
 376
 377 /* Claim resources for the PCI frontend as-is, backend won't allow changes */
 378 static int pcifront_claim_resource(struct pci_dev *dev, void *data)
 379 {
 380         struct pcifront_device *pdev = data;
 381         int i;
 382         struct resource *r;
 383
 384         for (i = 0; i < PCI_NUM_RESOURCES; i++) {
 385                 r = &dev->resource[i];
 386
 387                 if (!r->parent && r->start && r->flags) {
 388                         dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n",
 389                                 pci_name(dev), i);
 390                         if (pci_claim_resource(dev, i)) {
 391                                 dev_err(&pdev->xdev->dev, "Could not claim "
 392                                         "resource %s/%d! Device offline. Try "
 393                                         "giving less than 4GB to domain.\n",
 394                                         pci_name(dev), i);
 395                         }
 396                 }
 397         }
 398
 399         return 0;
 400 }
 401
 402 static int __devinit pcifront_scan_bus(struct pcifront_device *pdev,
 403                                 unsigned int domain, unsigned int bus,
 404                                 struct pci_bus *b)
 405 {
 406         struct pci_dev *d;
 407         unsigned int devfn;
 408
 409         /* Scan the bus for functions and add.
 410          * We omit handling of PCI bridge attachment because pciback prevents
 411          * bridges from being exported.
 412          */
 413         for (devfn = 0; devfn < 0x100; devfn++) {
 414                 d = pci_get_slot(b, devfn);
 415                 if (d) {
 416                         /* Device is already known. */
 417                         pci_dev_put(d);
 418                         continue;
 419                 }
 420
 421                 d = pci_scan_single_device(b, devfn);
 422                 if (d)
 423                         dev_info(&pdev->xdev->dev, "New device on "
 424                                  "%04x:%02x:%02x.%02x found.\n", domain, bus,
 425                                  PCI_SLOT(devfn), PCI_FUNC(devfn));
 426         }
 427
 428         return 0;
 429 }
 430
 431 static int __devinit pcifront_scan_root(struct pcifront_device *pdev,
 432                                  unsigned int domain, unsigned int bus)
 433 {
 434         struct pci_bus *b;
 435         struct pcifront_sd *sd = NULL;
 436         struct pci_bus_entry *bus_entry = NULL;
 437         int err = 0;
 438
 439 #ifndef CONFIG_PCI_DOMAINS
 440         if (domain != 0) {
 441                 dev_err(&pdev->xdev->dev,
 442                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 443                 dev_err(&pdev->xdev->dev,
 444                         "Please compile with CONFIG_PCI_DOMAINS\n");
 445                 err = -EINVAL;
 446                 goto err_out;
 447         }
 448 #endif
 449
 450         dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n",
 451                  domain, bus);
 452
 453         bus_entry = kmalloc(sizeof(*bus_entry), GFP_KERNEL);
 454         sd = kmalloc(sizeof(*sd), GFP_KERNEL);
 455         if (!bus_entry || !sd) {
 456                 err = -ENOMEM;
 457                 goto err_out;
 458         }
 459         pcifront_init_sd(sd, domain, bus, pdev);
 460
 461         b = pci_scan_bus_parented(&pdev->xdev->dev, bus,
 462                                   &pcifront_bus_ops, sd);
 463         if (!b) {
 464                 dev_err(&pdev->xdev->dev,
 465                         "Error creating PCI Frontend Bus!\n");
 466                 err = -ENOMEM;
 467                 goto err_out;
 468         }
 469
 470         bus_entry->bus = b;
 471
 472         list_add(&bus_entry->list, &pdev->root_buses);
 473
 474         /* pci_scan_bus_parented skips devices which do not have a have
 475         * devfn==0. The pcifront_scan_bus enumerates all devfn. */
 476         err = pcifront_scan_bus(pdev, domain, bus, b);
 477
 478         /* Claim resources before going "live" with our devices */
 479         pci_walk_bus(b, pcifront_claim_resource, pdev);
 480
 481         /* Create SysFS and notify udev of the devices. Aka: "going live" */
 482         pci_bus_add_devices(b);
 483
 484         return err;
 485
 486 err_out:
 487         kfree(bus_entry);
 488         kfree(sd);
 489
 490         return err;
 491 }
 492
 493 static int __devinit pcifront_rescan_root(struct pcifront_device *pdev,
 494                                    unsigned int domain, unsigned int bus)
 495 {
 496         int err;
 497         struct pci_bus *b;
 498
 499 #ifndef CONFIG_PCI_DOMAINS
 500         if (domain != 0) {
 501                 dev_err(&pdev->xdev->dev,
 502                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 503                 dev_err(&pdev->xdev->dev,
 504                         "Please compile with CONFIG_PCI_DOMAINS\n");
 505                 return -EINVAL;
 506         }
 507 #endif
 508
 509         dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
 510                  domain, bus);
 511
 512         b = pci_find_bus(domain, bus);
 513         if (!b)
 514                 /* If the bus is unknown, create it. */
 515                 return pcifront_scan_root(pdev, domain, bus);
 516
 517         err = pcifront_scan_bus(pdev, domain, bus, b);
 518
 519         /* Claim resources before going "live" with our devices */
 520         pci_walk_bus(b, pcifront_claim_resource, pdev);
 521
 522         /* Create SysFS and notify udev of the devices. Aka: "going live" */
 523         pci_bus_add_devices(b);
 524
 525         return err;
 526 }
 527
 528 static void free_root_bus_devs(struct pci_bus *bus)
 529 {
 530         struct pci_dev *dev;
 531
 532         while (!list_empty(&bus->devices)) {
 533                 dev = container_of(bus->devices.next, struct pci_dev,
 534                                    bus_list);
 535                 dev_dbg(&dev->dev, "removing device\n");
 536                 pci_remove_bus_device(dev);
 537         }
 538 }
 539
 540 static void pcifront_free_roots(struct pcifront_device *pdev)
 541 {
 542         struct pci_bus_entry *bus_entry, *t;
 543
 544         dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n");
 545
 546         list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) {
 547                 list_del(&bus_entry->list);
 548
 549                 free_root_bus_devs(bus_entry->bus);
 550
 551                 kfree(bus_entry->bus->sysdata);
 552
 553                 device_unregister(bus_entry->bus->bridge);
 554                 pci_remove_bus(bus_entry->bus);
 555
 556                 kfree(bus_entry);
 557         }
 558 }
 559
 560 static pci_ers_result_t pcifront_common_process(int cmd,
 561                                                 struct pcifront_device *pdev,
 562                                                 pci_channel_state_t state)
 563 {
 564         pci_ers_result_t result;
 565         struct pci_driver *pdrv;
 566         int bus = pdev->sh_info->aer_op.bus;
 567         int devfn = pdev->sh_info->aer_op.devfn;
 568         struct pci_dev *pcidev;
 569         int flag = 0;
 570
 571         dev_dbg(&pdev->xdev->dev,
 572                 "pcifront AER process: cmd %x (bus:%x, devfn%x)",
 573                 cmd, bus, devfn);
 574         result = PCI_ERS_RESULT_NONE;
 575
 576         pcidev = pci_get_bus_and_slot(bus, devfn);
 577         if (!pcidev || !pcidev->driver) {
 578                 dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
 579                 if (pcidev)
 580                         pci_dev_put(pcidev);
 581                 return result;
 582         }
 583         pdrv = pcidev->driver;
 584
 585         if (get_driver(&pdrv->driver)) {
 586                 if (pdrv->err_handler && pdrv->err_handler->error_detected) {
 587                         dev_dbg(&pcidev->dev,
 588                                 "trying to call AER service\n");
 589                         if (pcidev) {
 590                                 flag = 1;
 591                                 switch (cmd) {
 592                                 case XEN_PCI_OP_aer_detected:
 593                                         result = pdrv->err_handler->
 594                                                  error_detected(pcidev, state);
 595                                         break;
 596                                 case XEN_PCI_OP_aer_mmio:
 597                                         result = pdrv->err_handler->
 598                                                  mmio_enabled(pcidev);
 599                                         break;
 600                                 case XEN_PCI_OP_aer_slotreset:
 601                                         result = pdrv->err_handler->
 602                                                  slot_reset(pcidev);
 603                                         break;
 604                                 case XEN_PCI_OP_aer_resume:
 605                                         pdrv->err_handler->resume(pcidev);
 606                                         break;
 607                                 default:
 608                                         dev_err(&pdev->xdev->dev,
 609                                                 "bad request in aer recovery "
 610                                                 "operation!\n");
 611
 612                                 }
 613                         }
 614                 }
 615                 put_driver(&pdrv->driver);
 616         }
 617         if (!flag)
 618                 result = PCI_ERS_RESULT_NONE;
 619
 620         return result;
 621 }
 622
 623
 624 static void pcifront_do_aer(struct work_struct *data)
 625 {
 626         struct pcifront_device *pdev =
 627                 container_of(data, struct pcifront_device, op_work);
 628         int cmd = pdev->sh_info->aer_op.cmd;
 629         pci_channel_state_t state =
 630                 (pci_channel_state_t)pdev->sh_info->aer_op.err;
 631
 632         /*If a pci_conf op is in progress,
 633                 we have to wait until it is done before service aer op*/
 634         dev_dbg(&pdev->xdev->dev,
 635                 "pcifront service aer bus %x devfn %x\n",
 636                 pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn);
 637
 638         pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state);
 639
 640         /* Post the operation to the guest. */
 641         wmb();
 642         clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags);
 643         notify_remote_via_evtchn(pdev->evtchn);
 644
 645         /*in case of we lost an aer request in four lines time_window*/
 646         smp_mb__before_clear_bit();
 647         clear_bit(_PDEVB_op_active, &pdev->flags);
 648         smp_mb__after_clear_bit();
 649
 650         schedule_pcifront_aer_op(pdev);
 651
 652 }
 653
 654 static irqreturn_t pcifront_handler_aer(int irq, void *dev)
 655 {
 656         struct pcifront_device *pdev = dev;
 657         schedule_pcifront_aer_op(pdev);
 658         return IRQ_HANDLED;
 659 }
 660 static int pcifront_connect(struct pcifront_device *pdev)
 661 {
 662         int err = 0;
 663
 664         spin_lock(&pcifront_dev_lock);
 665
 666         if (!pcifront_dev) {
 667                 dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
 668                 pcifront_dev = pdev;
 669         } else {
 670                 dev_err(&pdev->xdev->dev, "PCI frontend already installed!\n");
 671                 err = -EEXIST;
 672         }
 673
 674         spin_unlock(&pcifront_dev_lock);
 675
 676         return err;
 677 }
 678
 679 static void pcifront_disconnect(struct pcifront_device *pdev)
 680 {
 681         spin_lock(&pcifront_dev_lock);
 682
 683         if (pdev == pcifront_dev) {
 684                 dev_info(&pdev->xdev->dev,
 685                          "Disconnecting PCI Frontend Buses\n");
 686                 pcifront_dev = NULL;
 687         }
 688
 689         spin_unlock(&pcifront_dev_lock);
 690 }
 691 static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev)
 692 {
 693         struct pcifront_device *pdev;
 694
 695         pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL);
 696         if (pdev == NULL)
 697                 goto out;
 698
 699         pdev->sh_info =
 700             (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL);
 701         if (pdev->sh_info == NULL) {
 702                 kfree(pdev);
 703                 pdev = NULL;
 704                 goto out;
 705         }
 706         pdev->sh_info->flags = 0;
 707
 708         /*Flag for registering PV AER handler*/
 709         set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags);
 710
 711         dev_set_drvdata(&xdev->dev, pdev);
 712         pdev->xdev = xdev;
 713
 714         INIT_LIST_HEAD(&pdev->root_buses);
 715
 716         spin_lock_init(&pdev->sh_info_lock);
 717
 718         pdev->evtchn = INVALID_EVTCHN;
 719         pdev->gnt_ref = INVALID_GRANT_REF;
 720         pdev->irq = -1;
 721
 722         INIT_WORK(&pdev->op_work, pcifront_do_aer);
 723
 724         dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n",
 725                 pdev, pdev->sh_info);
 726 out:
 727         return pdev;
 728 }
 729
 730 static void free_pdev(struct pcifront_device *pdev)
 731 {
 732         dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
 733
 734         pcifront_free_roots(pdev);
 735
 736         /*For PCIE_AER error handling job*/
 737         flush_scheduled_work();
 738
 739         if (pdev->irq >= 0)
 740                 unbind_from_irqhandler(pdev->irq, pdev);
 741
 742         if (pdev->evtchn != INVALID_EVTCHN)
 743                 xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
 744
 745         if (pdev->gnt_ref != INVALID_GRANT_REF)
 746                 gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
 747                                           (unsigned long)pdev->sh_info);
 748         else
 749                 free_page((unsigned long)pdev->sh_info);
 750
 751         dev_set_drvdata(&pdev->xdev->dev, NULL);
 752
 753         kfree(pdev);
 754 }
 755
 756 static int pcifront_publish_info(struct pcifront_device *pdev)
 757 {
 758         int err = 0;
 759         struct xenbus_transaction trans;
 760
 761         err = xenbus_grant_ring(pdev->xdev, virt_to_mfn(pdev->sh_info));
 762         if (err < 0)
 763                 goto out;
 764
 765         pdev->gnt_ref = err;
 766
 767         err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
 768         if (err)
 769                 goto out;
 770
 771         err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer,
 772                 0, "pcifront", pdev);
 773
 774         if (err < 0)
 775                 return err;
 776
 777         pdev->irq = err;
 778
 779 do_publish:
 780         err = xenbus_transaction_start(&trans);
 781         if (err) {
 782                 xenbus_dev_fatal(pdev->xdev, err,
 783                                  "Error writing configuration for backend "
 784                                  "(start transaction)");
 785                 goto out;
 786         }
 787
 788         err = xenbus_printf(trans, pdev->xdev->nodename,
 789                             "pci-op-ref", "%u", pdev->gnt_ref);
 790         if (!err)
 791                 err = xenbus_printf(trans, pdev->xdev->nodename,
 792                                     "event-channel", "%u", pdev->evtchn);
 793         if (!err)
 794                 err = xenbus_printf(trans, pdev->xdev->nodename,
 795                                     "magic", XEN_PCI_MAGIC);
 796
 797         if (err) {
 798                 xenbus_transaction_end(trans, 1);
 799                 xenbus_dev_fatal(pdev->xdev, err,
 800                                  "Error writing configuration for backend");
 801                 goto out;
 802         } else {
 803                 err = xenbus_transaction_end(trans, 0);
 804                 if (err == -EAGAIN)
 805                         goto do_publish;
 806                 else if (err) {
 807                         xenbus_dev_fatal(pdev->xdev, err,
 808                                          "Error completing transaction "
 809                                          "for backend");
 810                         goto out;
 811                 }
 812         }
 813
 814         xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
 815
 816         dev_dbg(&pdev->xdev->dev, "publishing successful!\n");
 817
 818 out:
 819         return err;
 820 }
 821
 822 static int __devinit pcifront_try_connect(struct pcifront_device *pdev)
 823 {
 824         int err = -EFAULT;
 825         int i, num_roots, len;
 826         char str[64];
 827         unsigned int domain, bus;
 828
 829
 830         /* Only connect once */
 831         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 832             XenbusStateInitialised)
 833                 goto out;
 834
 835         err = pcifront_connect(pdev);
 836         if (err) {
 837                 xenbus_dev_fatal(pdev->xdev, err,
 838                                  "Error connecting PCI Frontend");
 839                 goto out;
 840         }
 841
 842         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 843                            "root_num", "%d", &num_roots);
 844         if (err == -ENOENT) {
 845                 xenbus_dev_error(pdev->xdev, err,
 846                                  "No PCI Roots found, trying 0000:00");
 847                 err = pcifront_scan_root(pdev, 0, 0);
 848                 num_roots = 0;
 849         } else if (err != 1) {
 850                 if (err == 0)
 851                         err = -EINVAL;
 852                 xenbus_dev_fatal(pdev->xdev, err,
 853                                  "Error reading number of PCI roots");
 854                 goto out;
 855         }
 856
 857         for (i = 0; i < num_roots; i++) {
 858                 len = snprintf(str, sizeof(str), "root-%d", i);
 859                 if (unlikely(len >= (sizeof(str) - 1))) {
 860                         err = -ENOMEM;
 861                         goto out;
 862                 }
 863
 864                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 865                                    "%x:%x", &domain, &bus);
 866                 if (err != 2) {
 867                         if (err >= 0)
 868                                 err = -EINVAL;
 869                         xenbus_dev_fatal(pdev->xdev, err,
 870                                          "Error reading PCI root %d", i);
 871                         goto out;
 872                 }
 873
 874                 err = pcifront_scan_root(pdev, domain, bus);
 875                 if (err) {
 876                         xenbus_dev_fatal(pdev->xdev, err,
 877                                          "Error scanning PCI root %04x:%02x",
 878                                          domain, bus);
 879                         goto out;
 880                 }
 881         }
 882
 883         err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 884
 885 out:
 886         return err;
 887 }
 888
 889 static int pcifront_try_disconnect(struct pcifront_device *pdev)
 890 {
 891         int err = 0;
 892         enum xenbus_state prev_state;
 893
 894
 895         prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
 896
 897         if (prev_state >= XenbusStateClosing)
 898                 goto out;
 899
 900         if (prev_state == XenbusStateConnected) {
 901                 pcifront_free_roots(pdev);
 902                 pcifront_disconnect(pdev);
 903         }
 904
 905         err = xenbus_switch_state(pdev->xdev, XenbusStateClosed);
 906
 907 out:
 908
 909         return err;
 910 }
 911
 912 static int __devinit pcifront_attach_devices(struct pcifront_device *pdev)
 913 {
 914         int err = -EFAULT;
 915         int i, num_roots, len;
 916         unsigned int domain, bus;
 917         char str[64];
 918
 919         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 920             XenbusStateReconfiguring)
 921                 goto out;
 922
 923         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 924                            "root_num", "%d", &num_roots);
 925         if (err == -ENOENT) {
 926                 xenbus_dev_error(pdev->xdev, err,
 927                                  "No PCI Roots found, trying 0000:00");
 928                 err = pcifront_rescan_root(pdev, 0, 0);
 929                 num_roots = 0;
 930         } else if (err != 1) {
 931                 if (err == 0)
 932                         err = -EINVAL;
 933                 xenbus_dev_fatal(pdev->xdev, err,
 934                                  "Error reading number of PCI roots");
 935                 goto out;
 936         }
 937
 938         for (i = 0; i < num_roots; i++) {
 939                 len = snprintf(str, sizeof(str), "root-%d", i);
 940                 if (unlikely(len >= (sizeof(str) - 1))) {
 941                         err = -ENOMEM;
 942                         goto out;
 943                 }
 944
 945                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 946                                    "%x:%x", &domain, &bus);
 947                 if (err != 2) {
 948                         if (err >= 0)
 949                                 err = -EINVAL;
 950                         xenbus_dev_fatal(pdev->xdev, err,
 951                                          "Error reading PCI root %d", i);
 952                         goto out;
 953                 }
 954
 955                 err = pcifront_rescan_root(pdev, domain, bus);
 956                 if (err) {
 957                         xenbus_dev_fatal(pdev->xdev, err,
 958                                          "Error scanning PCI root %04x:%02x",
 959                                          domain, bus);
 960                         goto out;
 961                 }
 962         }
 963
 964         xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 965
 966 out:
 967         return err;
 968 }
 969
 970 static int pcifront_detach_devices(struct pcifront_device *pdev)
 971 {
 972         int err = 0;
 973         int i, num_devs;
 974         unsigned int domain, bus, slot, func;
 975         struct pci_bus *pci_bus;
 976         struct pci_dev *pci_dev;
 977         char str[64];
 978
 979         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 980             XenbusStateConnected)
 981                 goto out;
 982
 983         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d",
 984                            &num_devs);
 985         if (err != 1) {
 986                 if (err >= 0)
 987                         err = -EINVAL;
 988                 xenbus_dev_fatal(pdev->xdev, err,
 989                                  "Error reading number of PCI devices");
 990                 goto out;
 991         }
 992
 993         /* Find devices being detached and remove them. */
 994         for (i = 0; i < num_devs; i++) {
 995                 int l, state;
 996                 l = snprintf(str, sizeof(str), "state-%d", i);
 997                 if (unlikely(l >= (sizeof(str) - 1))) {
 998                         err = -ENOMEM;
 999                         goto out;
1000                 }
1001                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%d",
1002                                    &state);
1003                 if (err != 1)
1004                         state = XenbusStateUnknown;
1005
1006                 if (state != XenbusStateClosing)
1007                         continue;
1008
1009                 /* Remove device. */
1010                 l = snprintf(str, sizeof(str), "vdev-%d", i);
1011                 if (unlikely(l >= (sizeof(str) - 1))) {
1012                         err = -ENOMEM;
1013                         goto out;
1014                 }
1015                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
1016                                    "%x:%x:%x.%x", &domain, &bus, &slot, &func);
1017                 if (err != 4) {
1018                         if (err >= 0)
1019                                 err = -EINVAL;
1020                         xenbus_dev_fatal(pdev->xdev, err,
1021                                          "Error reading PCI device %d", i);
1022                         goto out;
1023                 }
1024
1025                 pci_bus = pci_find_bus(domain, bus);
1026                 if (!pci_bus) {
1027                         dev_dbg(&pdev->xdev->dev, "Cannot get bus %04x:%02x\n",
1028                                 domain, bus);
1029                         continue;
1030                 }
1031                 pci_dev = pci_get_slot(pci_bus, PCI_DEVFN(slot, func));
1032                 if (!pci_dev) {
1033                         dev_dbg(&pdev->xdev->dev,
1034                                 "Cannot get PCI device %04x:%02x:%02x.%02x\n",
1035                                 domain, bus, slot, func);
1036                         continue;
1037                 }
1038                 pci_remove_bus_device(pci_dev);
1039                 pci_dev_put(pci_dev);
1040
1041                 dev_dbg(&pdev->xdev->dev,
1042                         "PCI device %04x:%02x:%02x.%02x removed.\n",
1043                         domain, bus, slot, func);
1044         }
1045
1046         err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring);
1047
1048 out:
1049         return err;
1050 }
1051
1052 static void __init_refok pcifront_backend_changed(struct xenbus_device *xdev,
1053                                                   enum xenbus_state be_state)
1054 {
1055         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1056
1057         switch (be_state) {
1058         case XenbusStateUnknown:
1059         case XenbusStateInitialising:
1060         case XenbusStateInitWait:
1061         case XenbusStateInitialised:
1062         case XenbusStateClosed:
1063                 break;
1064
1065         case XenbusStateConnected:
1066                 pcifront_try_connect(pdev);
1067                 break;
1068
1069         case XenbusStateClosing:
1070                 dev_warn(&xdev->dev, "backend going away!\n");
1071                 pcifront_try_disconnect(pdev);
1072                 break;
1073
1074         case XenbusStateReconfiguring:
1075                 pcifront_detach_devices(pdev);
1076                 break;
1077
1078         case XenbusStateReconfigured:
1079                 pcifront_attach_devices(pdev);
1080                 break;
1081         }
1082 }
1083
1084 static int pcifront_xenbus_probe(struct xenbus_device *xdev,
1085                                  const struct xenbus_device_id *id)
1086 {
1087         int err = 0;
1088         struct pcifront_device *pdev = alloc_pdev(xdev);
1089
1090         if (pdev == NULL) {
1091                 err = -ENOMEM;
1092                 xenbus_dev_fatal(xdev, err,
1093                                  "Error allocating pcifront_device struct");
1094                 goto out;
1095         }
1096
1097         err = pcifront_publish_info(pdev);
1098         if (err)
1099                 free_pdev(pdev);
1100
1101 out:
1102         return err;
1103 }
1104
1105 static int pcifront_xenbus_remove(struct xenbus_device *xdev)
1106 {
1107         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1108         if (pdev)
1109                 free_pdev(pdev);
1110
1111         return 0;
1112 }
1113
1114 static const struct xenbus_device_id xenpci_ids[] = {
1115         {"pci"},
1116         {""},
1117 };
1118
1119 static struct xenbus_driver xenbus_pcifront_driver = {
1120         .name                   = "pcifront",
1121         .owner                  = THIS_MODULE,
1122         .ids                    = xenpci_ids,
1123         .probe                  = pcifront_xenbus_probe,
1124         .remove                 = pcifront_xenbus_remove,
1125         .otherend_changed       = pcifront_backend_changed,
1126 };
1127
1128 static int __init pcifront_init(void)
1129 {
1130         if (!xen_pv_domain() || xen_initial_domain())
1131                 return -ENODEV;
1132
1133         pci_frontend_registrar(1 /* enable */);
1134
1135         return xenbus_register_frontend(&xenbus_pcifront_driver);
1136 }
1137
1138 static void __exit pcifront_cleanup(void)
1139 {
1140         xenbus_unregister_driver(&xenbus_pcifront_driver);
1141         pci_frontend_registrar(0 /* disable */);
1142 }
1143 module_init(pcifront_init);
1144 module_exit(pcifront_cleanup);
1145
1146 MODULE_DESCRIPTION("Xen PCI passthrough frontend.");
1147 MODULE_LICENSE("GPL");
1148 MODULE_ALIAS("xen:pci");