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