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                 if (pcidev)
 600                         pci_dev_put(pcidev);
 601                 return result;
 602         }
 603         pdrv = pcidev->driver;
 604
 605         if (pdrv) {
 606                 if (pdrv->err_handler && pdrv->err_handler->error_detected) {
 607                         dev_dbg(&pcidev->dev,
 608                                 "trying to call AER service\n");
 609                         if (pcidev) {
 610                                 flag = 1;
 611                                 switch (cmd) {
 612                                 case XEN_PCI_OP_aer_detected:
 613                                         result = pdrv->err_handler->
 614                                                  error_detected(pcidev, state);
 615                                         break;
 616                                 case XEN_PCI_OP_aer_mmio:
 617                                         result = pdrv->err_handler->
 618                                                  mmio_enabled(pcidev);
 619                                         break;
 620                                 case XEN_PCI_OP_aer_slotreset:
 621                                         result = pdrv->err_handler->
 622                                                  slot_reset(pcidev);
 623                                         break;
 624                                 case XEN_PCI_OP_aer_resume:
 625                                         pdrv->err_handler->resume(pcidev);
 626                                         break;
 627                                 default:
 628                                         dev_err(&pdev->xdev->dev,
 629                                                 "bad request in aer recovery "
 630                                                 "operation!\n");
 631
 632                                 }
 633                         }
 634                 }
 635         }
 636         if (!flag)
 637                 result = PCI_ERS_RESULT_NONE;
 638
 639         return result;
 640 }
 641
 642
 643 static void pcifront_do_aer(struct work_struct *data)
 644 {
 645         struct pcifront_device *pdev =
 646                 container_of(data, struct pcifront_device, op_work);
 647         int cmd = pdev->sh_info->aer_op.cmd;
 648         pci_channel_state_t state =
 649                 (pci_channel_state_t)pdev->sh_info->aer_op.err;
 650
 651         /*If a pci_conf op is in progress,
 652                 we have to wait until it is done before service aer op*/
 653         dev_dbg(&pdev->xdev->dev,
 654                 "pcifront service aer bus %x devfn %x\n",
 655                 pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn);
 656
 657         pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state);
 658
 659         /* Post the operation to the guest. */
 660         wmb();
 661         clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags);
 662         notify_remote_via_evtchn(pdev->evtchn);
 663
 664         /*in case of we lost an aer request in four lines time_window*/
 665         smp_mb__before_clear_bit();
 666         clear_bit(_PDEVB_op_active, &pdev->flags);
 667         smp_mb__after_clear_bit();
 668
 669         schedule_pcifront_aer_op(pdev);
 670
 671 }
 672
 673 static irqreturn_t pcifront_handler_aer(int irq, void *dev)
 674 {
 675         struct pcifront_device *pdev = dev;
 676         schedule_pcifront_aer_op(pdev);
 677         return IRQ_HANDLED;
 678 }
 679 static int pcifront_connect_and_init_dma(struct pcifront_device *pdev)
 680 {
 681         int err = 0;
 682
 683         spin_lock(&pcifront_dev_lock);
 684
 685         if (!pcifront_dev) {
 686                 dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
 687                 pcifront_dev = pdev;
 688         } else
 689                 err = -EEXIST;
 690
 691         spin_unlock(&pcifront_dev_lock);
 692
 693         if (!err && !swiotlb_nr_tbl()) {
 694                 err = pci_xen_swiotlb_init_late();
 695                 if (err)
 696                         dev_err(&pdev->xdev->dev, "Could not setup SWIOTLB!\n");
 697         }
 698         return err;
 699 }
 700
 701 static void pcifront_disconnect(struct pcifront_device *pdev)
 702 {
 703         spin_lock(&pcifront_dev_lock);
 704
 705         if (pdev == pcifront_dev) {
 706                 dev_info(&pdev->xdev->dev,
 707                          "Disconnecting PCI Frontend Buses\n");
 708                 pcifront_dev = NULL;
 709         }
 710
 711         spin_unlock(&pcifront_dev_lock);
 712 }
 713 static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev)
 714 {
 715         struct pcifront_device *pdev;
 716
 717         pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL);
 718         if (pdev == NULL)
 719                 goto out;
 720
 721         pdev->sh_info =
 722             (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL);
 723         if (pdev->sh_info == NULL) {
 724                 kfree(pdev);
 725                 pdev = NULL;
 726                 goto out;
 727         }
 728         pdev->sh_info->flags = 0;
 729
 730         /*Flag for registering PV AER handler*/
 731         set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags);
 732
 733         dev_set_drvdata(&xdev->dev, pdev);
 734         pdev->xdev = xdev;
 735
 736         INIT_LIST_HEAD(&pdev->root_buses);
 737
 738         spin_lock_init(&pdev->sh_info_lock);
 739
 740         pdev->evtchn = INVALID_EVTCHN;
 741         pdev->gnt_ref = INVALID_GRANT_REF;
 742         pdev->irq = -1;
 743
 744         INIT_WORK(&pdev->op_work, pcifront_do_aer);
 745
 746         dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n",
 747                 pdev, pdev->sh_info);
 748 out:
 749         return pdev;
 750 }
 751
 752 static void free_pdev(struct pcifront_device *pdev)
 753 {
 754         dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
 755
 756         pcifront_free_roots(pdev);
 757
 758         cancel_work_sync(&pdev->op_work);
 759
 760         if (pdev->irq >= 0)
 761                 unbind_from_irqhandler(pdev->irq, pdev);
 762
 763         if (pdev->evtchn != INVALID_EVTCHN)
 764                 xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
 765
 766         if (pdev->gnt_ref != INVALID_GRANT_REF)
 767                 gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
 768                                           (unsigned long)pdev->sh_info);
 769         else
 770                 free_page((unsigned long)pdev->sh_info);
 771
 772         dev_set_drvdata(&pdev->xdev->dev, NULL);
 773
 774         kfree(pdev);
 775 }
 776
 777 static int pcifront_publish_info(struct pcifront_device *pdev)
 778 {
 779         int err = 0;
 780         struct xenbus_transaction trans;
 781
 782         err = xenbus_grant_ring(pdev->xdev, virt_to_mfn(pdev->sh_info));
 783         if (err < 0)
 784                 goto out;
 785
 786         pdev->gnt_ref = err;
 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                 num_roots = 0;
 870         } else if (err != 1) {
 871                 if (err == 0)
 872                         err = -EINVAL;
 873                 xenbus_dev_fatal(pdev->xdev, err,
 874                                  "Error reading number of PCI roots");
 875                 goto out;
 876         }
 877
 878         for (i = 0; i < num_roots; i++) {
 879                 len = snprintf(str, sizeof(str), "root-%d", i);
 880                 if (unlikely(len >= (sizeof(str) - 1))) {
 881                         err = -ENOMEM;
 882                         goto out;
 883                 }
 884
 885                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 886                                    "%x:%x", &domain, &bus);
 887                 if (err != 2) {
 888                         if (err >= 0)
 889                                 err = -EINVAL;
 890                         xenbus_dev_fatal(pdev->xdev, err,
 891                                          "Error reading PCI root %d", i);
 892                         goto out;
 893                 }
 894
 895                 err = pcifront_scan_root(pdev, domain, bus);
 896                 if (err) {
 897                         xenbus_dev_fatal(pdev->xdev, err,
 898                                          "Error scanning PCI root %04x:%02x",
 899                                          domain, bus);
 900                         goto out;
 901                 }
 902         }
 903
 904         err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 905
 906 out:
 907         return err;
 908 }
 909
 910 static int pcifront_try_disconnect(struct pcifront_device *pdev)
 911 {
 912         int err = 0;
 913         enum xenbus_state prev_state;
 914
 915
 916         prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
 917
 918         if (prev_state >= XenbusStateClosing)
 919                 goto out;
 920
 921         if (prev_state == XenbusStateConnected) {
 922                 pcifront_free_roots(pdev);
 923                 pcifront_disconnect(pdev);
 924         }
 925
 926         err = xenbus_switch_state(pdev->xdev, XenbusStateClosed);
 927
 928 out:
 929
 930         return err;
 931 }
 932
 933 static int pcifront_attach_devices(struct pcifront_device *pdev)
 934 {
 935         int err = -EFAULT;
 936         int i, num_roots, len;
 937         unsigned int domain, bus;
 938         char str[64];
 939
 940         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 941             XenbusStateReconfiguring)
 942                 goto out;
 943
 944         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 945                            "root_num", "%d", &num_roots);
 946         if (err == -ENOENT) {
 947                 xenbus_dev_error(pdev->xdev, err,
 948                                  "No PCI Roots found, trying 0000:00");
 949                 err = pcifront_rescan_root(pdev, 0, 0);
 950                 num_roots = 0;
 951         } else if (err != 1) {
 952                 if (err == 0)
 953                         err = -EINVAL;
 954                 xenbus_dev_fatal(pdev->xdev, err,
 955                                  "Error reading number of PCI roots");
 956                 goto out;
 957         }
 958
 959         for (i = 0; i < num_roots; i++) {
 960                 len = snprintf(str, sizeof(str), "root-%d", i);
 961                 if (unlikely(len >= (sizeof(str) - 1))) {
 962                         err = -ENOMEM;
 963                         goto out;
 964                 }
 965
 966                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 967                                    "%x:%x", &domain, &bus);
 968                 if (err != 2) {
 969                         if (err >= 0)
 970                                 err = -EINVAL;
 971                         xenbus_dev_fatal(pdev->xdev, err,
 972                                          "Error reading PCI root %d", i);
 973                         goto out;
 974                 }
 975
 976                 err = pcifront_rescan_root(pdev, domain, bus);
 977                 if (err) {
 978                         xenbus_dev_fatal(pdev->xdev, err,
 979                                          "Error scanning PCI root %04x:%02x",
 980                                          domain, bus);
 981                         goto out;
 982                 }
 983         }
 984
 985         xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 986
 987 out:
 988         return err;
 989 }
 990
 991 static int pcifront_detach_devices(struct pcifront_device *pdev)
 992 {
 993         int err = 0;
 994         int i, num_devs;
 995         unsigned int domain, bus, slot, func;
 996         struct pci_dev *pci_dev;
 997         char str[64];
 998
 999         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
1000             XenbusStateConnected)
1001                 goto out;
1002
1003         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d",
1004                            &num_devs);
1005         if (err != 1) {
1006                 if (err >= 0)
1007                         err = -EINVAL;
1008                 xenbus_dev_fatal(pdev->xdev, err,
1009                                  "Error reading number of PCI devices");
1010                 goto out;
1011         }
1012
1013         /* Find devices being detached and remove them. */
1014         for (i = 0; i < num_devs; i++) {
1015                 int l, state;
1016                 l = snprintf(str, sizeof(str), "state-%d", i);
1017                 if (unlikely(l >= (sizeof(str) - 1))) {
1018                         err = -ENOMEM;
1019                         goto out;
1020                 }
1021                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%d",
1022                                    &state);
1023                 if (err != 1)
1024                         state = XenbusStateUnknown;
1025
1026                 if (state != XenbusStateClosing)
1027                         continue;
1028
1029                 /* Remove device. */
1030                 l = snprintf(str, sizeof(str), "vdev-%d", i);
1031                 if (unlikely(l >= (sizeof(str) - 1))) {
1032                         err = -ENOMEM;
1033                         goto out;
1034                 }
1035                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
1036                                    "%x:%x:%x.%x", &domain, &bus, &slot, &func);
1037                 if (err != 4) {
1038                         if (err >= 0)
1039                                 err = -EINVAL;
1040                         xenbus_dev_fatal(pdev->xdev, err,
1041                                          "Error reading PCI device %d", i);
1042                         goto out;
1043                 }
1044
1045                 pci_dev = pci_get_domain_bus_and_slot(domain, bus,
1046                                 PCI_DEVFN(slot, func));
1047                 if (!pci_dev) {
1048                         dev_dbg(&pdev->xdev->dev,
1049                                 "Cannot get PCI device %04x:%02x:%02x.%d\n",
1050                                 domain, bus, slot, func);
1051                         continue;
1052                 }
1053                 pci_lock_rescan_remove();
1054                 pci_stop_and_remove_bus_device(pci_dev);
1055                 pci_dev_put(pci_dev);
1056                 pci_unlock_rescan_remove();
1057
1058                 dev_dbg(&pdev->xdev->dev,
1059                         "PCI device %04x:%02x:%02x.%d removed.\n",
1060                         domain, bus, slot, func);
1061         }
1062
1063         err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring);
1064
1065 out:
1066         return err;
1067 }
1068
1069 static void __init_refok pcifront_backend_changed(struct xenbus_device *xdev,
1070                                                   enum xenbus_state be_state)
1071 {
1072         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1073
1074         switch (be_state) {
1075         case XenbusStateUnknown:
1076         case XenbusStateInitialising:
1077         case XenbusStateInitWait:
1078         case XenbusStateInitialised:
1079                 break;
1080
1081         case XenbusStateConnected:
1082                 pcifront_try_connect(pdev);
1083                 break;
1084
1085         case XenbusStateClosed:
1086                 if (xdev->state == XenbusStateClosed)
1087                         break;
1088                 /* Missed the backend's CLOSING state -- fallthrough */
1089         case XenbusStateClosing:
1090                 dev_warn(&xdev->dev, "backend going away!\n");
1091                 pcifront_try_disconnect(pdev);
1092                 break;
1093
1094         case XenbusStateReconfiguring:
1095                 pcifront_detach_devices(pdev);
1096                 break;
1097
1098         case XenbusStateReconfigured:
1099                 pcifront_attach_devices(pdev);
1100                 break;
1101         }
1102 }
1103
1104 static int pcifront_xenbus_probe(struct xenbus_device *xdev,
1105                                  const struct xenbus_device_id *id)
1106 {
1107         int err = 0;
1108         struct pcifront_device *pdev = alloc_pdev(xdev);
1109
1110         if (pdev == NULL) {
1111                 err = -ENOMEM;
1112                 xenbus_dev_fatal(xdev, err,
1113                                  "Error allocating pcifront_device struct");
1114                 goto out;
1115         }
1116
1117         err = pcifront_publish_info(pdev);
1118         if (err)
1119                 free_pdev(pdev);
1120
1121 out:
1122         return err;
1123 }
1124
1125 static int pcifront_xenbus_remove(struct xenbus_device *xdev)
1126 {
1127         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1128         if (pdev)
1129                 free_pdev(pdev);
1130
1131         return 0;
1132 }
1133
1134 static const struct xenbus_device_id xenpci_ids[] = {
1135         {"pci"},
1136         {""},
1137 };
1138
1139 static DEFINE_XENBUS_DRIVER(xenpci, "pcifront",
1140         .probe                  = pcifront_xenbus_probe,
1141         .remove                 = pcifront_xenbus_remove,
1142         .otherend_changed       = pcifront_backend_changed,
1143 );
1144
1145 static int __init pcifront_init(void)
1146 {
1147         if (!xen_pv_domain() || xen_initial_domain())
1148                 return -ENODEV;
1149
1150         if (!xen_has_pv_devices())
1151                 return -ENODEV;
1152
1153         pci_frontend_registrar(1 /* enable */);
1154
1155         return xenbus_register_frontend(&xenpci_driver);
1156 }
1157
1158 static void __exit pcifront_cleanup(void)
1159 {
1160         xenbus_unregister_driver(&xenpci_driver);
1161         pci_frontend_registrar(0 /* disable */);
1162 }
1163 module_init(pcifront_init);
1164 module_exit(pcifront_cleanup);
1165
1166 MODULE_DESCRIPTION("Xen PCI passthrough frontend.");
1167 MODULE_LICENSE("GPL");
1168 MODULE_ALIAS("xen:pci");