kernel/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 #include <xen/platform_pci.h>
  24
  25 #include <asm/xen/swiotlb-xen.h>
  26 #define INVALID_GRANT_REF (0)
  27 #define INVALID_EVTCHN    (-1)
  28
  29 struct pci_bus_entry {
  30         struct list_head list;
  31         struct pci_bus *bus;
  32 };
  33
  34 #define _PDEVB_op_active                (0)
  35 #define PDEVB_op_active                 (1 << (_PDEVB_op_active))
  36
  37 struct pcifront_device {
  38         struct xenbus_device *xdev;
  39         struct list_head root_buses;
  40
  41         int evtchn;
  42         int gnt_ref;
  43
  44         int irq;
  45
  46         /* Lock this when doing any operations in sh_info */
  47         spinlock_t sh_info_lock;
  48         struct xen_pci_sharedinfo *sh_info;
  49         struct work_struct op_work;
  50         unsigned long flags;
  51
  52 };
  53
  54 struct pcifront_sd {
  55         int domain;
  56         struct pcifront_device *pdev;
  57 };
  58
  59 static inline struct pcifront_device *
  60 pcifront_get_pdev(struct pcifront_sd *sd)
  61 {
  62         return sd->pdev;
  63 }
  64
  65 static inline void pcifront_init_sd(struct pcifront_sd *sd,
  66                                     unsigned int domain, unsigned int bus,
  67                                     struct pcifront_device *pdev)
  68 {
  69         sd->domain = domain;
  70         sd->pdev = pdev;
  71 }
  72
  73 static DEFINE_SPINLOCK(pcifront_dev_lock);
  74 static struct pcifront_device *pcifront_dev;
  75
  76 static int verbose_request;
  77 module_param(verbose_request, int, 0644);
  78
  79 static int errno_to_pcibios_err(int errno)
  80 {
  81         switch (errno) {
  82         case XEN_PCI_ERR_success:
  83                 return PCIBIOS_SUCCESSFUL;
  84
  85         case XEN_PCI_ERR_dev_not_found:
  86                 return PCIBIOS_DEVICE_NOT_FOUND;
  87
  88         case XEN_PCI_ERR_invalid_offset:
  89         case XEN_PCI_ERR_op_failed:
  90                 return PCIBIOS_BAD_REGISTER_NUMBER;
  91
  92         case XEN_PCI_ERR_not_implemented:
  93                 return PCIBIOS_FUNC_NOT_SUPPORTED;
  94
  95         case XEN_PCI_ERR_access_denied:
  96                 return PCIBIOS_SET_FAILED;
  97         }
  98         return errno;
  99 }
 100
 101 static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev)
 102 {
 103         if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
 104                 && !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) {
 105                 dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n");
 106                 schedule_work(&pdev->op_work);
 107         }
 108 }
 109
 110 static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 111 {
 112         int err = 0;
 113         struct xen_pci_op *active_op = &pdev->sh_info->op;
 114         unsigned long irq_flags;
 115         evtchn_port_t port = pdev->evtchn;
 116         unsigned irq = pdev->irq;
 117         s64 ns, ns_timeout;
 118         struct timeval tv;
 119
 120         spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
 121
 122         memcpy(active_op, op, sizeof(struct xen_pci_op));
 123
 124         /* Go */
 125         wmb();
 126         set_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
 127         notify_remote_via_evtchn(port);
 128
 129         /*
 130          * We set a poll timeout of 3 seconds but give up on return after
 131          * 2 seconds. It is better to time out too late rather than too early
 132          * (in the latter case we end up continually re-executing poll() with a
 133          * timeout in the past). 1s difference gives plenty of slack for error.
 134          */
 135         do_gettimeofday(&tv);
 136         ns_timeout = timeval_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;
 137
 138         xen_clear_irq_pending(irq);
 139
 140         while (test_bit(_XEN_PCIF_active,
 141                         (unsigned long *)&pdev->sh_info->flags)) {
 142                 xen_poll_irq_timeout(irq, jiffies + 3*HZ);
 143                 xen_clear_irq_pending(irq);
 144                 do_gettimeofday(&tv);
 145                 ns = timeval_to_ns(&tv);
 146                 if (ns > ns_timeout) {
 147                         dev_err(&pdev->xdev->dev,
 148                                 "pciback not responding!!!\n");
 149                         clear_bit(_XEN_PCIF_active,
 150                                   (unsigned long *)&pdev->sh_info->flags);
 151                         err = XEN_PCI_ERR_dev_not_found;
 152                         goto out;
 153                 }
 154         }
 155
 156         /*
 157         * We might lose backend service request since we
 158         * reuse same evtchn with pci_conf backend response. So re-schedule
 159         * aer pcifront service.
 160         */
 161         if (test_bit(_XEN_PCIB_active,
 162                         (unsigned long *)&pdev->sh_info->flags)) {
 163                 dev_err(&pdev->xdev->dev,
 164                         "schedule aer pcifront service\n");
 165                 schedule_pcifront_aer_op(pdev);
 166         }
 167
 168         memcpy(op, active_op, sizeof(struct xen_pci_op));
 169
 170         err = op->err;
 171 out:
 172         spin_unlock_irqrestore(&pdev->sh_info_lock, irq_flags);
 173         return err;
 174 }
 175
 176 /* Access to this function is spinlocked in drivers/pci/access.c */
 177 static int pcifront_bus_read(struct pci_bus *bus, unsigned int devfn,
 178                              int where, int size, u32 *val)
 179 {
 180         int err = 0;
 181         struct xen_pci_op op = {
 182                 .cmd    = XEN_PCI_OP_conf_read,
 183                 .domain = pci_domain_nr(bus),
 184                 .bus    = bus->number,
 185                 .devfn  = devfn,
 186                 .offset = where,
 187                 .size   = size,
 188         };
 189         struct pcifront_sd *sd = bus->sysdata;
 190         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 191
 192         if (verbose_request)
 193                 dev_info(&pdev->xdev->dev,
 194                          "read dev=%04x:%02x:%02x.%d - offset %x size %d\n",
 195                          pci_domain_nr(bus), bus->number, PCI_SLOT(devfn),
 196                          PCI_FUNC(devfn), where, size);
 197
 198         err = do_pci_op(pdev, &op);
 199
 200         if (likely(!err)) {
 201                 if (verbose_request)
 202                         dev_info(&pdev->xdev->dev, "read got back value %x\n",
 203                                  op.value);
 204
 205                 *val = op.value;
 206         } else if (err == -ENODEV) {
 207                 /* No device here, pretend that it just returned 0 */
 208                 err = 0;
 209                 *val = 0;
 210         }
 211
 212         return errno_to_pcibios_err(err);
 213 }
 214
 215 /* Access to this function is spinlocked in drivers/pci/access.c */
 216 static int pcifront_bus_write(struct pci_bus *bus, unsigned int devfn,
 217                               int where, int size, u32 val)
 218 {
 219         struct xen_pci_op op = {
 220                 .cmd    = XEN_PCI_OP_conf_write,
 221                 .domain = pci_domain_nr(bus),
 222                 .bus    = bus->number,
 223                 .devfn  = devfn,
 224                 .offset = where,
 225                 .size   = size,
 226                 .value  = val,
 227         };
 228         struct pcifront_sd *sd = bus->sysdata;
 229         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 230
 231         if (verbose_request)
 232                 dev_info(&pdev->xdev->dev,
 233                          "write dev=%04x:%02x:%02x.%d - "
 234                          "offset %x size %d val %x\n",
 235                          pci_domain_nr(bus), bus->number,
 236                          PCI_SLOT(devfn), PCI_FUNC(devfn), where, size, val);
 237
 238         return errno_to_pcibios_err(do_pci_op(pdev, &op));
 239 }
 240
 241 static struct pci_ops pcifront_bus_ops = {
 242         .read = pcifront_bus_read,
 243         .write = pcifront_bus_write,
 244 };
 245
 246 #ifdef CONFIG_PCI_MSI
 247 static int pci_frontend_enable_msix(struct pci_dev *dev,
 248                                     int vector[], int nvec)
 249 {
 250         int err;
 251         int i;
 252         struct xen_pci_op op = {
 253                 .cmd    = XEN_PCI_OP_enable_msix,
 254                 .domain = pci_domain_nr(dev->bus),
 255                 .bus = dev->bus->number,
 256                 .devfn = dev->devfn,
 257                 .value = nvec,
 258         };
 259         struct pcifront_sd *sd = dev->bus->sysdata;
 260         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 261         struct msi_desc *entry;
 262
 263         if (nvec > SH_INFO_MAX_VEC) {
 264                 dev_err(&dev->dev, "too much vector for pci frontend: %x."
 265                                    " Increase SH_INFO_MAX_VEC.\n", nvec);
 266                 return -EINVAL;
 267         }
 268
 269         i = 0;
 270         list_for_each_entry(entry, &dev->msi_list, list) {
 271                 op.msix_entries[i].entry = entry->msi_attrib.entry_nr;
 272                 /* Vector is useless at this point. */
 273                 op.msix_entries[i].vector = -1;
 274                 i++;
 275         }
 276
 277         err = do_pci_op(pdev, &op);
 278
 279         if (likely(!err)) {
 280                 if (likely(!op.value)) {
 281                         /* we get the result */
 282                         for (i = 0; i < nvec; i++) {
 283                                 if (op.msix_entries[i].vector <= 0) {
 284                                         dev_warn(&dev->dev, "MSI-X entry %d is invalid: %d!\n",
 285                                                 i, op.msix_entries[i].vector);
 286                                         err = -EINVAL;
 287                                         vector[i] = -1;
 288                                         continue;
 289                                 }
 290                                 vector[i] = op.msix_entries[i].vector;
 291                         }
 292                 } else {
 293                         printk(KERN_DEBUG "enable msix get value %x\n",
 294                                 op.value);
 295                         err = op.value;
 296                 }
 297         } else {
 298                 dev_err(&dev->dev, "enable msix get err %x\n", err);
 299         }
 300         return err;
 301 }
 302
 303 static void pci_frontend_disable_msix(struct pci_dev *dev)
 304 {
 305         int err;
 306         struct xen_pci_op op = {
 307                 .cmd    = XEN_PCI_OP_disable_msix,
 308                 .domain = pci_domain_nr(dev->bus),
 309                 .bus = dev->bus->number,
 310                 .devfn = dev->devfn,
 311         };
 312         struct pcifront_sd *sd = dev->bus->sysdata;
 313         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 314
 315         err = do_pci_op(pdev, &op);
 316
 317         /* What should do for error ? */
 318         if (err)
 319                 dev_err(&dev->dev, "pci_disable_msix get err %x\n", err);
 320 }
 321
 322 static int pci_frontend_enable_msi(struct pci_dev *dev, int vector[])
 323 {
 324         int err;
 325         struct xen_pci_op op = {
 326                 .cmd    = XEN_PCI_OP_enable_msi,
 327                 .domain = pci_domain_nr(dev->bus),
 328                 .bus = dev->bus->number,
 329                 .devfn = dev->devfn,
 330         };
 331         struct pcifront_sd *sd = dev->bus->sysdata;
 332         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 333
 334         err = do_pci_op(pdev, &op);
 335         if (likely(!err)) {
 336                 vector[0] = op.value;
 337                 if (op.value <= 0) {
 338                         dev_warn(&dev->dev, "MSI entry is invalid: %d!\n",
 339                                 op.value);
 340                         err = -EINVAL;
 341                         vector[0] = -1;
 342                 }
 343         } else {
 344                 dev_err(&dev->dev, "pci frontend enable msi failed for dev "
 345                                     "%x:%x\n", op.bus, op.devfn);
 346                 err = -EINVAL;
 347         }
 348         return err;
 349 }
 350
 351 static void pci_frontend_disable_msi(struct pci_dev *dev)
 352 {
 353         int err;
 354         struct xen_pci_op op = {
 355                 .cmd    = XEN_PCI_OP_disable_msi,
 356                 .domain = pci_domain_nr(dev->bus),
 357                 .bus = dev->bus->number,
 358                 .devfn = dev->devfn,
 359         };
 360         struct pcifront_sd *sd = dev->bus->sysdata;
 361         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 362
 363         err = do_pci_op(pdev, &op);
 364         if (err == XEN_PCI_ERR_dev_not_found) {
 365                 /* XXX No response from backend, what shall we do? */
 366                 printk(KERN_DEBUG "get no response from backend for disable MSI\n");
 367                 return;
 368         }
 369         if (err)
 370                 /* how can pciback notify us fail? */
 371                 printk(KERN_DEBUG "get fake response frombackend\n");
 372 }
 373
 374 static struct xen_pci_frontend_ops pci_frontend_ops = {
 375         .enable_msi = pci_frontend_enable_msi,
 376         .disable_msi = pci_frontend_disable_msi,
 377         .enable_msix = pci_frontend_enable_msix,
 378         .disable_msix = pci_frontend_disable_msix,
 379 };
 380
 381 static void pci_frontend_registrar(int enable)
 382 {
 383         if (enable)
 384                 xen_pci_frontend = &pci_frontend_ops;
 385         else
 386                 xen_pci_frontend = NULL;
 387 };
 388 #else
 389 static inline void pci_frontend_registrar(int enable) { };
 390 #endif /* CONFIG_PCI_MSI */
 391
 392 /* Claim resources for the PCI frontend as-is, backend won't allow changes */
 393 static int pcifront_claim_resource(struct pci_dev *dev, void *data)
 394 {
 395         struct pcifront_device *pdev = data;
 396         int i;
 397         struct resource *r;
 398
 399         for (i = 0; i < PCI_NUM_RESOURCES; i++) {
 400                 r = &dev->resource[i];
 401
 402                 if (!r->parent && r->start && r->flags) {
 403                         dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n",
 404                                 pci_name(dev), i);
 405                         if (pci_claim_resource(dev, i)) {
 406                                 dev_err(&pdev->xdev->dev, "Could not claim resource %s/%d! "
 407                                         "Device offline. Try using e820_host=1 in the guest config.\n",
 408                                         pci_name(dev), i);
 409                         }
 410                 }
 411         }
 412
 413         return 0;
 414 }
 415
 416 static int pcifront_scan_bus(struct pcifront_device *pdev,
 417                                 unsigned int domain, unsigned int bus,
 418                                 struct pci_bus *b)
 419 {
 420         struct pci_dev *d;
 421         unsigned int devfn;
 422
 423         /* Scan the bus for functions and add.
 424          * We omit handling of PCI bridge attachment because pciback prevents
 425          * bridges from being exported.
 426          */
 427         for (devfn = 0; devfn < 0x100; devfn++) {
 428                 d = pci_get_slot(b, devfn);
 429                 if (d) {
 430                         /* Device is already known. */
 431                         pci_dev_put(d);
 432                         continue;
 433                 }
 434
 435                 d = pci_scan_single_device(b, devfn);
 436                 if (d)
 437                         dev_info(&pdev->xdev->dev, "New device on "
 438                                  "%04x:%02x:%02x.%d found.\n", domain, bus,
 439                                  PCI_SLOT(devfn), PCI_FUNC(devfn));
 440         }
 441
 442         return 0;
 443 }
 444
 445 static int pcifront_scan_root(struct pcifront_device *pdev,
 446                                  unsigned int domain, unsigned int bus)
 447 {
 448         struct pci_bus *b;
 449         struct pcifront_sd *sd = NULL;
 450         struct pci_bus_entry *bus_entry = NULL;
 451         int err = 0;
 452
 453 #ifndef CONFIG_PCI_DOMAINS
 454         if (domain != 0) {
 455                 dev_err(&pdev->xdev->dev,
 456                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 457                 dev_err(&pdev->xdev->dev,
 458                         "Please compile with CONFIG_PCI_DOMAINS\n");
 459                 err = -EINVAL;
 460                 goto err_out;
 461         }
 462 #endif
 463
 464         dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n",
 465                  domain, bus);
 466
 467         bus_entry = kmalloc(sizeof(*bus_entry), GFP_KERNEL);
 468         sd = kmalloc(sizeof(*sd), GFP_KERNEL);
 469         if (!bus_entry || !sd) {
 470                 err = -ENOMEM;
 471                 goto err_out;
 472         }
 473         pcifront_init_sd(sd, domain, bus, pdev);
 474
 475         pci_lock_rescan_remove();
 476
 477         b = pci_scan_bus_parented(&pdev->xdev->dev, bus,
 478                                   &pcifront_bus_ops, sd);
 479         if (!b) {
 480                 dev_err(&pdev->xdev->dev,
 481                         "Error creating PCI Frontend Bus!\n");
 482                 err = -ENOMEM;
 483                 pci_unlock_rescan_remove();
 484                 goto err_out;
 485         }
 486
 487         bus_entry->bus = b;
 488
 489         list_add(&bus_entry->list, &pdev->root_buses);
 490
 491         /* pci_scan_bus_parented skips devices which do not have a have
 492         * devfn==0. The pcifront_scan_bus enumerates all devfn. */
 493         err = pcifront_scan_bus(pdev, domain, bus, b);
 494
 495         /* Claim resources before going "live" with our devices */
 496         pci_walk_bus(b, pcifront_claim_resource, pdev);
 497
 498         /* Create SysFS and notify udev of the devices. Aka: "going live" */
 499         pci_bus_add_devices(b);
 500
 501         pci_unlock_rescan_remove();
 502         return err;
 503
 504 err_out:
 505         kfree(bus_entry);
 506         kfree(sd);
 507
 508         return err;
 509 }
 510
 511 static int pcifront_rescan_root(struct pcifront_device *pdev,
 512                                    unsigned int domain, unsigned int bus)
 513 {
 514         int err;
 515         struct pci_bus *b;
 516
 517 #ifndef CONFIG_PCI_DOMAINS
 518         if (domain != 0) {
 519                 dev_err(&pdev->xdev->dev,
 520                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 521                 dev_err(&pdev->xdev->dev,
 522                         "Please compile with CONFIG_PCI_DOMAINS\n");
 523                 return -EINVAL;
 524         }
 525 #endif
 526
 527         dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
 528                  domain, bus);
 529
 530         b = pci_find_bus(domain, bus);
 531         if (!b)
 532                 /* If the bus is unknown, create it. */
 533                 return pcifront_scan_root(pdev, domain, bus);
 534
 535         err = pcifront_scan_bus(pdev, domain, bus, b);
 536
 537         /* Claim resources before going "live" with our devices */
 538         pci_walk_bus(b, pcifront_claim_resource, pdev);
 539
 540         /* Create SysFS and notify udev of the devices. Aka: "going live" */
 541         pci_bus_add_devices(b);
 542
 543         return err;
 544 }
 545
 546 static void free_root_bus_devs(struct pci_bus *bus)
 547 {
 548         struct pci_dev *dev;
 549
 550         while (!list_empty(&bus->devices)) {
 551                 dev = container_of(bus->devices.next, struct pci_dev,
 552                                    bus_list);
 553                 dev_dbg(&dev->dev, "removing device\n");
 554                 pci_stop_and_remove_bus_device(dev);
 555         }
 556 }
 557
 558 static void pcifront_free_roots(struct pcifront_device *pdev)
 559 {
 560         struct pci_bus_entry *bus_entry, *t;
 561
 562         dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n");
 563
 564         pci_lock_rescan_remove();
 565         list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) {
 566                 list_del(&bus_entry->list);
 567
 568                 free_root_bus_devs(bus_entry->bus);
 569
 570                 kfree(bus_entry->bus->sysdata);
 571
 572                 device_unregister(bus_entry->bus->bridge);
 573                 pci_remove_bus(bus_entry->bus);
 574
 575                 kfree(bus_entry);
 576         }
 577         pci_unlock_rescan_remove();
 578 }
 579
 580 static pci_ers_result_t pcifront_common_process(int cmd,
 581                                                 struct pcifront_device *pdev,
 582                                                 pci_channel_state_t state)
 583 {
 584         pci_ers_result_t result;
 585         struct pci_driver *pdrv;
 586         int bus = pdev->sh_info->aer_op.bus;
 587         int devfn = pdev->sh_info->aer_op.devfn;
 588         struct pci_dev *pcidev;
 589         int flag = 0;
 590
 591         dev_dbg(&pdev->xdev->dev,
 592                 "pcifront AER process: cmd %x (bus:%x, devfn%x)",
 593                 cmd, bus, devfn);
 594         result = PCI_ERS_RESULT_NONE;
 595
 596         pcidev = pci_get_bus_and_slot(bus, devfn);
 597         if (!pcidev || !pcidev->driver) {
 598                 dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
 599                 pci_dev_put(pcidev);
 600                 return result;
 601         }
 602         pdrv = pcidev->driver;
 603
 604         if (pdrv) {
 605                 if (pdrv->err_handler && pdrv->err_handler->error_detected) {
 606                         dev_dbg(&pcidev->dev,
 607                                 "trying to call AER service\n");
 608                         if (pcidev) {
 609                                 flag = 1;
 610                                 switch (cmd) {
 611                                 case XEN_PCI_OP_aer_detected:
 612                                         result = pdrv->err_handler->
 613                                                  error_detected(pcidev, state);
 614                                         break;
 615                                 case XEN_PCI_OP_aer_mmio:
 616                                         result = pdrv->err_handler->
 617                                                  mmio_enabled(pcidev);
 618                                         break;
 619                                 case XEN_PCI_OP_aer_slotreset:
 620                                         result = pdrv->err_handler->
 621                                                  slot_reset(pcidev);
 622                                         break;
 623                                 case XEN_PCI_OP_aer_resume:
 624                                         pdrv->err_handler->resume(pcidev);
 625                                         break;
 626                                 default:
 627                                         dev_err(&pdev->xdev->dev,
 628                                                 "bad request in aer recovery "
 629                                                 "operation!\n");
 630
 631                                 }
 632                         }
 633                 }
 634         }
 635         if (!flag)
 636                 result = PCI_ERS_RESULT_NONE;
 637
 638         return result;
 639 }
 640
 641
 642 static void pcifront_do_aer(struct work_struct *data)
 643 {
 644         struct pcifront_device *pdev =
 645                 container_of(data, struct pcifront_device, op_work);
 646         int cmd = pdev->sh_info->aer_op.cmd;
 647         pci_channel_state_t state =
 648                 (pci_channel_state_t)pdev->sh_info->aer_op.err;
 649
 650         /*If a pci_conf op is in progress,
 651                 we have to wait until it is done before service aer op*/
 652         dev_dbg(&pdev->xdev->dev,
 653                 "pcifront service aer bus %x devfn %x\n",
 654                 pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn);
 655
 656         pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state);
 657
 658         /* Post the operation to the guest. */
 659         wmb();
 660         clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags);
 661         notify_remote_via_evtchn(pdev->evtchn);
 662
 663         /*in case of we lost an aer request in four lines time_window*/
 664         smp_mb__before_atomic();
 665         clear_bit(_PDEVB_op_active, &pdev->flags);
 666         smp_mb__after_atomic();
 667
 668         schedule_pcifront_aer_op(pdev);
 669
 670 }
 671
 672 static irqreturn_t pcifront_handler_aer(int irq, void *dev)
 673 {
 674         struct pcifront_device *pdev = dev;
 675         schedule_pcifront_aer_op(pdev);
 676         return IRQ_HANDLED;
 677 }
 678 static int pcifront_connect_and_init_dma(struct pcifront_device *pdev)
 679 {
 680         int err = 0;
 681
 682         spin_lock(&pcifront_dev_lock);
 683
 684         if (!pcifront_dev) {
 685                 dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
 686                 pcifront_dev = pdev;
 687         } else
 688                 err = -EEXIST;
 689
 690         spin_unlock(&pcifront_dev_lock);
 691
 692         if (!err && !swiotlb_nr_tbl()) {
 693                 err = pci_xen_swiotlb_init_late();
 694                 if (err)
 695                         dev_err(&pdev->xdev->dev, "Could not setup SWIOTLB!\n");
 696         }
 697         return err;
 698 }
 699
 700 static void pcifront_disconnect(struct pcifront_device *pdev)
 701 {
 702         spin_lock(&pcifront_dev_lock);
 703
 704         if (pdev == pcifront_dev) {
 705                 dev_info(&pdev->xdev->dev,
 706                          "Disconnecting PCI Frontend Buses\n");
 707                 pcifront_dev = NULL;
 708         }
 709
 710         spin_unlock(&pcifront_dev_lock);
 711 }
 712 static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev)
 713 {
 714         struct pcifront_device *pdev;
 715
 716         pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL);
 717         if (pdev == NULL)
 718                 goto out;
 719
 720         pdev->sh_info =
 721             (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL);
 722         if (pdev->sh_info == NULL) {
 723                 kfree(pdev);
 724                 pdev = NULL;
 725                 goto out;
 726         }
 727         pdev->sh_info->flags = 0;
 728
 729         /*Flag for registering PV AER handler*/
 730         set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags);
 731
 732         dev_set_drvdata(&xdev->dev, pdev);
 733         pdev->xdev = xdev;
 734
 735         INIT_LIST_HEAD(&pdev->root_buses);
 736
 737         spin_lock_init(&pdev->sh_info_lock);
 738
 739         pdev->evtchn = INVALID_EVTCHN;
 740         pdev->gnt_ref = INVALID_GRANT_REF;
 741         pdev->irq = -1;
 742
 743         INIT_WORK(&pdev->op_work, pcifront_do_aer);
 744
 745         dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n",
 746                 pdev, pdev->sh_info);
 747 out:
 748         return pdev;
 749 }
 750
 751 static void free_pdev(struct pcifront_device *pdev)
 752 {
 753         dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
 754
 755         pcifront_free_roots(pdev);
 756
 757         cancel_work_sync(&pdev->op_work);
 758
 759         if (pdev->irq >= 0)
 760                 unbind_from_irqhandler(pdev->irq, pdev);
 761
 762         if (pdev->evtchn != INVALID_EVTCHN)
 763                 xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
 764
 765         if (pdev->gnt_ref != INVALID_GRANT_REF)
 766                 gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
 767                                           (unsigned long)pdev->sh_info);
 768         else
 769                 free_page((unsigned long)pdev->sh_info);
 770
 771         dev_set_drvdata(&pdev->xdev->dev, NULL);
 772
 773         kfree(pdev);
 774 }
 775
 776 static int pcifront_publish_info(struct pcifront_device *pdev)
 777 {
 778         int err = 0;
 779         struct xenbus_transaction trans;
 780         grant_ref_t gref;
 781
 782         err = xenbus_grant_ring(pdev->xdev, pdev->sh_info, 1, &gref);
 783         if (err < 0)
 784                 goto out;
 785
 786         pdev->gnt_ref = gref;
 787
 788         err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
 789         if (err)
 790                 goto out;
 791
 792         err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer,
 793                 0, "pcifront", pdev);
 794
 795         if (err < 0)
 796                 return err;
 797
 798         pdev->irq = err;
 799
 800 do_publish:
 801         err = xenbus_transaction_start(&trans);
 802         if (err) {
 803                 xenbus_dev_fatal(pdev->xdev, err,
 804                                  "Error writing configuration for backend "
 805                                  "(start transaction)");
 806                 goto out;
 807         }
 808
 809         err = xenbus_printf(trans, pdev->xdev->nodename,
 810                             "pci-op-ref", "%u", pdev->gnt_ref);
 811         if (!err)
 812                 err = xenbus_printf(trans, pdev->xdev->nodename,
 813                                     "event-channel", "%u", pdev->evtchn);
 814         if (!err)
 815                 err = xenbus_printf(trans, pdev->xdev->nodename,
 816                                     "magic", XEN_PCI_MAGIC);
 817
 818         if (err) {
 819                 xenbus_transaction_end(trans, 1);
 820                 xenbus_dev_fatal(pdev->xdev, err,
 821                                  "Error writing configuration for backend");
 822                 goto out;
 823         } else {
 824                 err = xenbus_transaction_end(trans, 0);
 825                 if (err == -EAGAIN)
 826                         goto do_publish;
 827                 else if (err) {
 828                         xenbus_dev_fatal(pdev->xdev, err,
 829                                          "Error completing transaction "
 830                                          "for backend");
 831                         goto out;
 832                 }
 833         }
 834
 835         xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
 836
 837         dev_dbg(&pdev->xdev->dev, "publishing successful!\n");
 838
 839 out:
 840         return err;
 841 }
 842
 843 static int pcifront_try_connect(struct pcifront_device *pdev)
 844 {
 845         int err = -EFAULT;
 846         int i, num_roots, len;
 847         char str[64];
 848         unsigned int domain, bus;
 849
 850
 851         /* Only connect once */
 852         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 853             XenbusStateInitialised)
 854                 goto out;
 855
 856         err = pcifront_connect_and_init_dma(pdev);
 857         if (err && err != -EEXIST) {
 858                 xenbus_dev_fatal(pdev->xdev, err,
 859                                  "Error setting up PCI Frontend");
 860                 goto out;
 861         }
 862
 863         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 864                            "root_num", "%d", &num_roots);
 865         if (err == -ENOENT) {
 866                 xenbus_dev_error(pdev->xdev, err,
 867                                  "No PCI Roots found, trying 0000:00");
 868                 err = pcifront_scan_root(pdev, 0, 0);
 869                 if (err) {
 870                         xenbus_dev_fatal(pdev->xdev, err,
 871                                          "Error scanning PCI root 0000:00");
 872                         goto out;
 873                 }
 874                 num_roots = 0;
 875         } else if (err != 1) {
 876                 if (err == 0)
 877                         err = -EINVAL;
 878                 xenbus_dev_fatal(pdev->xdev, err,
 879                                  "Error reading number of PCI roots");
 880                 goto out;
 881         }
 882
 883         for (i = 0; i < num_roots; i++) {
 884                 len = snprintf(str, sizeof(str), "root-%d", i);
 885                 if (unlikely(len >= (sizeof(str) - 1))) {
 886                         err = -ENOMEM;
 887                         goto out;
 888                 }
 889
 890                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 891                                    "%x:%x", &domain, &bus);
 892                 if (err != 2) {
 893                         if (err >= 0)
 894                                 err = -EINVAL;
 895                         xenbus_dev_fatal(pdev->xdev, err,
 896                                          "Error reading PCI root %d", i);
 897                         goto out;
 898                 }
 899
 900                 err = pcifront_scan_root(pdev, domain, bus);
 901                 if (err) {
 902                         xenbus_dev_fatal(pdev->xdev, err,
 903                                          "Error scanning PCI root %04x:%02x",
 904                                          domain, bus);
 905                         goto out;
 906                 }
 907         }
 908
 909         err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 910
 911 out:
 912         return err;
 913 }
 914
 915 static int pcifront_try_disconnect(struct pcifront_device *pdev)
 916 {
 917         int err = 0;
 918         enum xenbus_state prev_state;
 919
 920
 921         prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
 922
 923         if (prev_state >= XenbusStateClosing)
 924                 goto out;
 925
 926         if (prev_state == XenbusStateConnected) {
 927                 pcifront_free_roots(pdev);
 928                 pcifront_disconnect(pdev);
 929         }
 930
 931         err = xenbus_switch_state(pdev->xdev, XenbusStateClosed);
 932
 933 out:
 934
 935         return err;
 936 }
 937
 938 static int pcifront_attach_devices(struct pcifront_device *pdev)
 939 {
 940         int err = -EFAULT;
 941         int i, num_roots, len;
 942         unsigned int domain, bus;
 943         char str[64];
 944
 945         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 946             XenbusStateReconfiguring)
 947                 goto out;
 948
 949         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 950                            "root_num", "%d", &num_roots);
 951         if (err == -ENOENT) {
 952                 xenbus_dev_error(pdev->xdev, err,
 953                                  "No PCI Roots found, trying 0000:00");
 954                 err = pcifront_rescan_root(pdev, 0, 0);
 955                 if (err) {
 956                         xenbus_dev_fatal(pdev->xdev, err,
 957                                          "Error scanning PCI root 0000:00");
 958                         goto out;
 959                 }
 960                 num_roots = 0;
 961         } else if (err != 1) {
 962                 if (err == 0)
 963                         err = -EINVAL;
 964                 xenbus_dev_fatal(pdev->xdev, err,
 965                                  "Error reading number of PCI roots");
 966                 goto out;
 967         }
 968
 969         for (i = 0; i < num_roots; i++) {
 970                 len = snprintf(str, sizeof(str), "root-%d", i);
 971                 if (unlikely(len >= (sizeof(str) - 1))) {
 972                         err = -ENOMEM;
 973                         goto out;
 974                 }
 975
 976                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 977                                    "%x:%x", &domain, &bus);
 978                 if (err != 2) {
 979                         if (err >= 0)
 980                                 err = -EINVAL;
 981                         xenbus_dev_fatal(pdev->xdev, err,
 982                                          "Error reading PCI root %d", i);
 983                         goto out;
 984                 }
 985
 986                 err = pcifront_rescan_root(pdev, domain, bus);
 987                 if (err) {
 988                         xenbus_dev_fatal(pdev->xdev, err,
 989                                          "Error scanning PCI root %04x:%02x",
 990                                          domain, bus);
 991                         goto out;
 992                 }
 993         }
 994
 995         xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 996
 997 out:
 998         return err;
 999 }
1000
1001 static int pcifront_detach_devices(struct pcifront_device *pdev)
1002 {
1003         int err = 0;
1004         int i, num_devs;
1005         unsigned int domain, bus, slot, func;
1006         struct pci_dev *pci_dev;
1007         char str[64];
1008
1009         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
1010             XenbusStateConnected)
1011                 goto out;
1012
1013         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d",
1014                            &num_devs);
1015         if (err != 1) {
1016                 if (err >= 0)
1017                         err = -EINVAL;
1018                 xenbus_dev_fatal(pdev->xdev, err,
1019                                  "Error reading number of PCI devices");
1020                 goto out;
1021         }
1022
1023         /* Find devices being detached and remove them. */
1024         for (i = 0; i < num_devs; i++) {
1025                 int l, state;
1026                 l = snprintf(str, sizeof(str), "state-%d", i);
1027                 if (unlikely(l >= (sizeof(str) - 1))) {
1028                         err = -ENOMEM;
1029                         goto out;
1030                 }
1031                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%d",
1032                                    &state);
1033                 if (err != 1)
1034                         state = XenbusStateUnknown;
1035
1036                 if (state != XenbusStateClosing)
1037                         continue;
1038
1039                 /* Remove device. */
1040                 l = snprintf(str, sizeof(str), "vdev-%d", i);
1041                 if (unlikely(l >= (sizeof(str) - 1))) {
1042                         err = -ENOMEM;
1043                         goto out;
1044                 }
1045                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
1046                                    "%x:%x:%x.%x", &domain, &bus, &slot, &func);
1047                 if (err != 4) {
1048                         if (err >= 0)
1049                                 err = -EINVAL;
1050                         xenbus_dev_fatal(pdev->xdev, err,
1051                                          "Error reading PCI device %d", i);
1052                         goto out;
1053                 }
1054
1055                 pci_dev = pci_get_domain_bus_and_slot(domain, bus,
1056                                 PCI_DEVFN(slot, func));
1057                 if (!pci_dev) {
1058                         dev_dbg(&pdev->xdev->dev,
1059                                 "Cannot get PCI device %04x:%02x:%02x.%d\n",
1060                                 domain, bus, slot, func);
1061                         continue;
1062                 }
1063                 pci_lock_rescan_remove();
1064                 pci_stop_and_remove_bus_device(pci_dev);
1065                 pci_dev_put(pci_dev);
1066                 pci_unlock_rescan_remove();
1067
1068                 dev_dbg(&pdev->xdev->dev,
1069                         "PCI device %04x:%02x:%02x.%d removed.\n",
1070                         domain, bus, slot, func);
1071         }
1072
1073         err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring);
1074
1075 out:
1076         return err;
1077 }
1078
1079 static void __init_refok pcifront_backend_changed(struct xenbus_device *xdev,
1080                                                   enum xenbus_state be_state)
1081 {
1082         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1083
1084         switch (be_state) {
1085         case XenbusStateUnknown:
1086         case XenbusStateInitialising:
1087         case XenbusStateInitWait:
1088         case XenbusStateInitialised:
1089                 break;
1090
1091         case XenbusStateConnected:
1092                 pcifront_try_connect(pdev);
1093                 break;
1094
1095         case XenbusStateClosed:
1096                 if (xdev->state == XenbusStateClosed)
1097                         break;
1098                 /* Missed the backend's CLOSING state -- fallthrough */
1099         case XenbusStateClosing:
1100                 dev_warn(&xdev->dev, "backend going away!\n");
1101                 pcifront_try_disconnect(pdev);
1102                 break;
1103
1104         case XenbusStateReconfiguring:
1105                 pcifront_detach_devices(pdev);
1106                 break;
1107
1108         case XenbusStateReconfigured:
1109                 pcifront_attach_devices(pdev);
1110                 break;
1111         }
1112 }
1113
1114 static int pcifront_xenbus_probe(struct xenbus_device *xdev,
1115                                  const struct xenbus_device_id *id)
1116 {
1117         int err = 0;
1118         struct pcifront_device *pdev = alloc_pdev(xdev);
1119
1120         if (pdev == NULL) {
1121                 err = -ENOMEM;
1122                 xenbus_dev_fatal(xdev, err,
1123                                  "Error allocating pcifront_device struct");
1124                 goto out;
1125         }
1126
1127         err = pcifront_publish_info(pdev);
1128         if (err)
1129                 free_pdev(pdev);
1130
1131 out:
1132         return err;
1133 }
1134
1135 static int pcifront_xenbus_remove(struct xenbus_device *xdev)
1136 {
1137         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1138         if (pdev)
1139                 free_pdev(pdev);
1140
1141         return 0;
1142 }
1143
1144 static const struct xenbus_device_id xenpci_ids[] = {
1145         {"pci"},
1146         {""},
1147 };
1148
1149 static struct xenbus_driver xenpci_driver = {
1150         .name                   = "pcifront",
1151         .ids                    = xenpci_ids,
1152         .probe                  = pcifront_xenbus_probe,
1153         .remove                 = pcifront_xenbus_remove,
1154         .otherend_changed       = pcifront_backend_changed,
1155 };
1156
1157 static int __init pcifront_init(void)
1158 {
1159         if (!xen_pv_domain() || xen_initial_domain())
1160                 return -ENODEV;
1161
1162         if (!xen_has_pv_devices())
1163                 return -ENODEV;
1164
1165         pci_frontend_registrar(1 /* enable */);
1166
1167         return xenbus_register_frontend(&xenpci_driver);
1168 }
1169
1170 static void __exit pcifront_cleanup(void)
1171 {
1172         xenbus_unregister_driver(&xenpci_driver);
1173         pci_frontend_registrar(0 /* disable */);
1174 }
1175 module_init(pcifront_init);
1176 module_exit(pcifront_cleanup);
1177
1178 MODULE_DESCRIPTION("Xen PCI passthrough frontend.");
1179 MODULE_LICENSE("GPL");
1180 MODULE_ALIAS("xen:pci");