drivers/pci/xen-pcifront.c

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