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 <linux/ktime.h>
  24 #include <xen/platform_pci.h>
  25
  26 #include <asm/xen/swiotlb-xen.h>
  27 #define INVALID_GRANT_REF (0)
  28 #define INVALID_EVTCHN    (-1)
  29
  30 struct pci_bus_entry {
  31         struct list_head list;
  32         struct pci_bus *bus;
  33 };
  34
  35 #define _PDEVB_op_active                (0)
  36 #define PDEVB_op_active                 (1 << (_PDEVB_op_active))
  37
  38 struct pcifront_device {
  39         struct xenbus_device *xdev;
  40         struct list_head root_buses;
  41
  42         int evtchn;
  43         int gnt_ref;
  44
  45         int irq;
  46
  47         /* Lock this when doing any operations in sh_info */
  48         spinlock_t sh_info_lock;
  49         struct xen_pci_sharedinfo *sh_info;
  50         struct work_struct op_work;
  51         unsigned long flags;
  52
  53 };
  54
  55 struct pcifront_sd {
  56         int domain;
  57         struct pcifront_device *pdev;
  58 };
  59
  60 static inline struct pcifront_device *
  61 pcifront_get_pdev(struct pcifront_sd *sd)
  62 {
  63         return sd->pdev;
  64 }
  65
  66 static inline void pcifront_init_sd(struct pcifront_sd *sd,
  67                                     unsigned int domain, unsigned int bus,
  68                                     struct pcifront_device *pdev)
  69 {
  70         sd->domain = domain;
  71         sd->pdev = pdev;
  72 }
  73
  74 static DEFINE_SPINLOCK(pcifront_dev_lock);
  75 static struct pcifront_device *pcifront_dev;
  76
  77 static int verbose_request;
  78 module_param(verbose_request, int, 0644);
  79
  80 static int errno_to_pcibios_err(int errno)
  81 {
  82         switch (errno) {
  83         case XEN_PCI_ERR_success:
  84                 return PCIBIOS_SUCCESSFUL;
  85
  86         case XEN_PCI_ERR_dev_not_found:
  87                 return PCIBIOS_DEVICE_NOT_FOUND;
  88
  89         case XEN_PCI_ERR_invalid_offset:
  90         case XEN_PCI_ERR_op_failed:
  91                 return PCIBIOS_BAD_REGISTER_NUMBER;
  92
  93         case XEN_PCI_ERR_not_implemented:
  94                 return PCIBIOS_FUNC_NOT_SUPPORTED;
  95
  96         case XEN_PCI_ERR_access_denied:
  97                 return PCIBIOS_SET_FAILED;
  98         }
  99         return errno;
 100 }
 101
 102 static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev)
 103 {
 104         if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
 105                 && !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) {
 106                 dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n");
 107                 schedule_work(&pdev->op_work);
 108         }
 109 }
 110
 111 static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 112 {
 113         int err = 0;
 114         struct xen_pci_op *active_op = &pdev->sh_info->op;
 115         unsigned long irq_flags;
 116         evtchn_port_t port = pdev->evtchn;
 117         unsigned irq = pdev->irq;
 118         s64 ns, ns_timeout;
 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         ns_timeout = ktime_get_ns() + 2 * (s64)NSEC_PER_SEC;
 136
 137         xen_clear_irq_pending(irq);
 138
 139         while (test_bit(_XEN_PCIF_active,
 140                         (unsigned long *)&pdev->sh_info->flags)) {
 141                 xen_poll_irq_timeout(irq, jiffies + 3*HZ);
 142                 xen_clear_irq_pending(irq);
 143                 ns = ktime_get_ns();
 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 static 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         for_each_pci_msi_entry(entry, dev) {
 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 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 pcifront_scan_root(struct pcifront_device *pdev,
 444                                  unsigned int domain, unsigned int bus)
 445 {
 446         struct pci_bus *b;
 447         LIST_HEAD(resources);
 448         struct pcifront_sd *sd = NULL;
 449         struct pci_bus_entry *bus_entry = NULL;
 450         int err = 0;
 451         static struct resource busn_res = {
 452                 .start = 0,
 453                 .end = 255,
 454                 .flags = IORESOURCE_BUS,
 455         };
 456
 457 #ifndef CONFIG_PCI_DOMAINS
 458         if (domain != 0) {
 459                 dev_err(&pdev->xdev->dev,
 460                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 461                 dev_err(&pdev->xdev->dev,
 462                         "Please compile with CONFIG_PCI_DOMAINS\n");
 463                 err = -EINVAL;
 464                 goto err_out;
 465         }
 466 #endif
 467
 468         dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n",
 469                  domain, bus);
 470
 471         bus_entry = kmalloc(sizeof(*bus_entry), GFP_KERNEL);
 472         sd = kmalloc(sizeof(*sd), GFP_KERNEL);
 473         if (!bus_entry || !sd) {
 474                 err = -ENOMEM;
 475                 goto err_out;
 476         }
 477         pci_add_resource(&resources, &ioport_resource);
 478         pci_add_resource(&resources, &iomem_resource);
 479         pci_add_resource(&resources, &busn_res);
 480         pcifront_init_sd(sd, domain, bus, pdev);
 481
 482         pci_lock_rescan_remove();
 483
 484         b = pci_scan_root_bus(&pdev->xdev->dev, bus,
 485                                   &pcifront_bus_ops, sd, &resources);
 486         if (!b) {
 487                 dev_err(&pdev->xdev->dev,
 488                         "Error creating PCI Frontend Bus!\n");
 489                 err = -ENOMEM;
 490                 pci_unlock_rescan_remove();
 491                 pci_free_resource_list(&resources);
 492                 goto err_out;
 493         }
 494
 495         bus_entry->bus = b;
 496
 497         list_add(&bus_entry->list, &pdev->root_buses);
 498
 499         /* pci_scan_root_bus skips devices which do not have a
 500         * devfn==0. The pcifront_scan_bus enumerates all devfn. */
 501         err = pcifront_scan_bus(pdev, domain, bus, b);
 502
 503         /* Claim resources before going "live" with our devices */
 504         pci_walk_bus(b, pcifront_claim_resource, pdev);
 505
 506         /* Create SysFS and notify udev of the devices. Aka: "going live" */
 507         pci_bus_add_devices(b);
 508
 509         pci_unlock_rescan_remove();
 510         return err;
 511
 512 err_out:
 513         kfree(bus_entry);
 514         kfree(sd);
 515
 516         return err;
 517 }
 518
 519 static int pcifront_rescan_root(struct pcifront_device *pdev,
 520                                    unsigned int domain, unsigned int bus)
 521 {
 522         int err;
 523         struct pci_bus *b;
 524
 525 #ifndef CONFIG_PCI_DOMAINS
 526         if (domain != 0) {
 527                 dev_err(&pdev->xdev->dev,
 528                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 529                 dev_err(&pdev->xdev->dev,
 530                         "Please compile with CONFIG_PCI_DOMAINS\n");
 531                 return -EINVAL;
 532         }
 533 #endif
 534
 535         dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
 536                  domain, bus);
 537
 538         b = pci_find_bus(domain, bus);
 539         if (!b)
 540                 /* If the bus is unknown, create it. */
 541                 return pcifront_scan_root(pdev, domain, bus);
 542
 543         err = pcifront_scan_bus(pdev, domain, bus, b);
 544
 545         /* Claim resources before going "live" with our devices */
 546         pci_walk_bus(b, pcifront_claim_resource, pdev);
 547
 548         /* Create SysFS and notify udev of the devices. Aka: "going live" */
 549         pci_bus_add_devices(b);
 550
 551         return err;
 552 }
 553
 554 static void free_root_bus_devs(struct pci_bus *bus)
 555 {
 556         struct pci_dev *dev;
 557
 558         while (!list_empty(&bus->devices)) {
 559                 dev = container_of(bus->devices.next, struct pci_dev,
 560                                    bus_list);
 561                 dev_dbg(&dev->dev, "removing device\n");
 562                 pci_stop_and_remove_bus_device(dev);
 563         }
 564 }
 565
 566 static void pcifront_free_roots(struct pcifront_device *pdev)
 567 {
 568         struct pci_bus_entry *bus_entry, *t;
 569
 570         dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n");
 571
 572         pci_lock_rescan_remove();
 573         list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) {
 574                 list_del(&bus_entry->list);
 575
 576                 free_root_bus_devs(bus_entry->bus);
 577
 578                 kfree(bus_entry->bus->sysdata);
 579
 580                 device_unregister(bus_entry->bus->bridge);
 581                 pci_remove_bus(bus_entry->bus);
 582
 583                 kfree(bus_entry);
 584         }
 585         pci_unlock_rescan_remove();
 586 }
 587
 588 static pci_ers_result_t pcifront_common_process(int cmd,
 589                                                 struct pcifront_device *pdev,
 590                                                 pci_channel_state_t state)
 591 {
 592         pci_ers_result_t result;
 593         struct pci_driver *pdrv;
 594         int bus = pdev->sh_info->aer_op.bus;
 595         int devfn = pdev->sh_info->aer_op.devfn;
 596         struct pci_dev *pcidev;
 597         int flag = 0;
 598
 599         dev_dbg(&pdev->xdev->dev,
 600                 "pcifront AER process: cmd %x (bus:%x, devfn%x)",
 601                 cmd, bus, devfn);
 602         result = PCI_ERS_RESULT_NONE;
 603
 604         pcidev = pci_get_bus_and_slot(bus, devfn);
 605         if (!pcidev || !pcidev->driver) {
 606                 dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
 607                 pci_dev_put(pcidev);
 608                 return result;
 609         }
 610         pdrv = pcidev->driver;
 611
 612         if (pdrv) {
 613                 if (pdrv->err_handler && pdrv->err_handler->error_detected) {
 614                         dev_dbg(&pcidev->dev,
 615                                 "trying to call AER service\n");
 616                         if (pcidev) {
 617                                 flag = 1;
 618                                 switch (cmd) {
 619                                 case XEN_PCI_OP_aer_detected:
 620                                         result = pdrv->err_handler->
 621                                                  error_detected(pcidev, state);
 622                                         break;
 623                                 case XEN_PCI_OP_aer_mmio:
 624                                         result = pdrv->err_handler->
 625                                                  mmio_enabled(pcidev);
 626                                         break;
 627                                 case XEN_PCI_OP_aer_slotreset:
 628                                         result = pdrv->err_handler->
 629                                                  slot_reset(pcidev);
 630                                         break;
 631                                 case XEN_PCI_OP_aer_resume:
 632                                         pdrv->err_handler->resume(pcidev);
 633                                         break;
 634                                 default:
 635                                         dev_err(&pdev->xdev->dev,
 636                                                 "bad request in aer recovery "
 637                                                 "operation!\n");
 638
 639                                 }
 640                         }
 641                 }
 642         }
 643         if (!flag)
 644                 result = PCI_ERS_RESULT_NONE;
 645
 646         return result;
 647 }
 648
 649
 650 static void pcifront_do_aer(struct work_struct *data)
 651 {
 652         struct pcifront_device *pdev =
 653                 container_of(data, struct pcifront_device, op_work);
 654         int cmd = pdev->sh_info->aer_op.cmd;
 655         pci_channel_state_t state =
 656                 (pci_channel_state_t)pdev->sh_info->aer_op.err;
 657
 658         /*If a pci_conf op is in progress,
 659                 we have to wait until it is done before service aer op*/
 660         dev_dbg(&pdev->xdev->dev,
 661                 "pcifront service aer bus %x devfn %x\n",
 662                 pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn);
 663
 664         pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state);
 665
 666         /* Post the operation to the guest. */
 667         wmb();
 668         clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags);
 669         notify_remote_via_evtchn(pdev->evtchn);
 670
 671         /*in case of we lost an aer request in four lines time_window*/
 672         smp_mb__before_atomic();
 673         clear_bit(_PDEVB_op_active, &pdev->flags);
 674         smp_mb__after_atomic();
 675
 676         schedule_pcifront_aer_op(pdev);
 677
 678 }
 679
 680 static irqreturn_t pcifront_handler_aer(int irq, void *dev)
 681 {
 682         struct pcifront_device *pdev = dev;
 683         schedule_pcifront_aer_op(pdev);
 684         return IRQ_HANDLED;
 685 }
 686 static int pcifront_connect_and_init_dma(struct pcifront_device *pdev)
 687 {
 688         int err = 0;
 689
 690         spin_lock(&pcifront_dev_lock);
 691
 692         if (!pcifront_dev) {
 693                 dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
 694                 pcifront_dev = pdev;
 695         } else
 696                 err = -EEXIST;
 697
 698         spin_unlock(&pcifront_dev_lock);
 699
 700         if (!err && !swiotlb_nr_tbl()) {
 701                 err = pci_xen_swiotlb_init_late();
 702                 if (err)
 703                         dev_err(&pdev->xdev->dev, "Could not setup SWIOTLB!\n");
 704         }
 705         return err;
 706 }
 707
 708 static void pcifront_disconnect(struct pcifront_device *pdev)
 709 {
 710         spin_lock(&pcifront_dev_lock);
 711
 712         if (pdev == pcifront_dev) {
 713                 dev_info(&pdev->xdev->dev,
 714                          "Disconnecting PCI Frontend Buses\n");
 715                 pcifront_dev = NULL;
 716         }
 717
 718         spin_unlock(&pcifront_dev_lock);
 719 }
 720 static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev)
 721 {
 722         struct pcifront_device *pdev;
 723
 724         pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL);
 725         if (pdev == NULL)
 726                 goto out;
 727
 728         pdev->sh_info =
 729             (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL);
 730         if (pdev->sh_info == NULL) {
 731                 kfree(pdev);
 732                 pdev = NULL;
 733                 goto out;
 734         }
 735         pdev->sh_info->flags = 0;
 736
 737         /*Flag for registering PV AER handler*/
 738         set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags);
 739
 740         dev_set_drvdata(&xdev->dev, pdev);
 741         pdev->xdev = xdev;
 742
 743         INIT_LIST_HEAD(&pdev->root_buses);
 744
 745         spin_lock_init(&pdev->sh_info_lock);
 746
 747         pdev->evtchn = INVALID_EVTCHN;
 748         pdev->gnt_ref = INVALID_GRANT_REF;
 749         pdev->irq = -1;
 750
 751         INIT_WORK(&pdev->op_work, pcifront_do_aer);
 752
 753         dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n",
 754                 pdev, pdev->sh_info);
 755 out:
 756         return pdev;
 757 }
 758
 759 static void free_pdev(struct pcifront_device *pdev)
 760 {
 761         dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
 762
 763         pcifront_free_roots(pdev);
 764
 765         cancel_work_sync(&pdev->op_work);
 766
 767         if (pdev->irq >= 0)
 768                 unbind_from_irqhandler(pdev->irq, pdev);
 769
 770         if (pdev->evtchn != INVALID_EVTCHN)
 771                 xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
 772
 773         if (pdev->gnt_ref != INVALID_GRANT_REF)
 774                 gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
 775                                           (unsigned long)pdev->sh_info);
 776         else
 777                 free_page((unsigned long)pdev->sh_info);
 778
 779         dev_set_drvdata(&pdev->xdev->dev, NULL);
 780
 781         kfree(pdev);
 782 }
 783
 784 static int pcifront_publish_info(struct pcifront_device *pdev)
 785 {
 786         int err = 0;
 787         struct xenbus_transaction trans;
 788         grant_ref_t gref;
 789
 790         err = xenbus_grant_ring(pdev->xdev, pdev->sh_info, 1, &gref);
 791         if (err < 0)
 792                 goto out;
 793
 794         pdev->gnt_ref = gref;
 795
 796         err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
 797         if (err)
 798                 goto out;
 799
 800         err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer,
 801                 0, "pcifront", pdev);
 802
 803         if (err < 0)
 804                 return err;
 805
 806         pdev->irq = err;
 807
 808 do_publish:
 809         err = xenbus_transaction_start(&trans);
 810         if (err) {
 811                 xenbus_dev_fatal(pdev->xdev, err,
 812                                  "Error writing configuration for backend "
 813                                  "(start transaction)");
 814                 goto out;
 815         }
 816
 817         err = xenbus_printf(trans, pdev->xdev->nodename,
 818                             "pci-op-ref", "%u", pdev->gnt_ref);
 819         if (!err)
 820                 err = xenbus_printf(trans, pdev->xdev->nodename,
 821                                     "event-channel", "%u", pdev->evtchn);
 822         if (!err)
 823                 err = xenbus_printf(trans, pdev->xdev->nodename,
 824                                     "magic", XEN_PCI_MAGIC);
 825
 826         if (err) {
 827                 xenbus_transaction_end(trans, 1);
 828                 xenbus_dev_fatal(pdev->xdev, err,
 829                                  "Error writing configuration for backend");
 830                 goto out;
 831         } else {
 832                 err = xenbus_transaction_end(trans, 0);
 833                 if (err == -EAGAIN)
 834                         goto do_publish;
 835                 else if (err) {
 836                         xenbus_dev_fatal(pdev->xdev, err,
 837                                          "Error completing transaction "
 838                                          "for backend");
 839                         goto out;
 840                 }
 841         }
 842
 843         xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
 844
 845         dev_dbg(&pdev->xdev->dev, "publishing successful!\n");
 846
 847 out:
 848         return err;
 849 }
 850
 851 static int pcifront_try_connect(struct pcifront_device *pdev)
 852 {
 853         int err = -EFAULT;
 854         int i, num_roots, len;
 855         char str[64];
 856         unsigned int domain, bus;
 857
 858
 859         /* Only connect once */
 860         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 861             XenbusStateInitialised)
 862                 goto out;
 863
 864         err = pcifront_connect_and_init_dma(pdev);
 865         if (err && err != -EEXIST) {
 866                 xenbus_dev_fatal(pdev->xdev, err,
 867                                  "Error setting up PCI Frontend");
 868                 goto out;
 869         }
 870
 871         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 872                            "root_num", "%d", &num_roots);
 873         if (err == -ENOENT) {
 874                 xenbus_dev_error(pdev->xdev, err,
 875                                  "No PCI Roots found, trying 0000:00");
 876                 err = pcifront_scan_root(pdev, 0, 0);
 877                 if (err) {
 878                         xenbus_dev_fatal(pdev->xdev, err,
 879                                          "Error scanning PCI root 0000:00");
 880                         goto out;
 881                 }
 882                 num_roots = 0;
 883         } else if (err != 1) {
 884                 if (err == 0)
 885                         err = -EINVAL;
 886                 xenbus_dev_fatal(pdev->xdev, err,
 887                                  "Error reading number of PCI roots");
 888                 goto out;
 889         }
 890
 891         for (i = 0; i < num_roots; i++) {
 892                 len = snprintf(str, sizeof(str), "root-%d", i);
 893                 if (unlikely(len >= (sizeof(str) - 1))) {
 894                         err = -ENOMEM;
 895                         goto out;
 896                 }
 897
 898                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 899                                    "%x:%x", &domain, &bus);
 900                 if (err != 2) {
 901                         if (err >= 0)
 902                                 err = -EINVAL;
 903                         xenbus_dev_fatal(pdev->xdev, err,
 904                                          "Error reading PCI root %d", i);
 905                         goto out;
 906                 }
 907
 908                 err = pcifront_scan_root(pdev, domain, bus);
 909                 if (err) {
 910                         xenbus_dev_fatal(pdev->xdev, err,
 911                                          "Error scanning PCI root %04x:%02x",
 912                                          domain, bus);
 913                         goto out;
 914                 }
 915         }
 916
 917         err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 918
 919 out:
 920         return err;
 921 }
 922
 923 static int pcifront_try_disconnect(struct pcifront_device *pdev)
 924 {
 925         int err = 0;
 926         enum xenbus_state prev_state;
 927
 928
 929         prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
 930
 931         if (prev_state >= XenbusStateClosing)
 932                 goto out;
 933
 934         if (prev_state == XenbusStateConnected) {
 935                 pcifront_free_roots(pdev);
 936                 pcifront_disconnect(pdev);
 937         }
 938
 939         err = xenbus_switch_state(pdev->xdev, XenbusStateClosed);
 940
 941 out:
 942
 943         return err;
 944 }
 945
 946 static int pcifront_attach_devices(struct pcifront_device *pdev)
 947 {
 948         int err = -EFAULT;
 949         int i, num_roots, len;
 950         unsigned int domain, bus;
 951         char str[64];
 952
 953         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 954             XenbusStateReconfiguring)
 955                 goto out;
 956
 957         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 958                            "root_num", "%d", &num_roots);
 959         if (err == -ENOENT) {
 960                 xenbus_dev_error(pdev->xdev, err,
 961                                  "No PCI Roots found, trying 0000:00");
 962                 err = pcifront_rescan_root(pdev, 0, 0);
 963                 if (err) {
 964                         xenbus_dev_fatal(pdev->xdev, err,
 965                                          "Error scanning PCI root 0000:00");
 966                         goto out;
 967                 }
 968                 num_roots = 0;
 969         } else if (err != 1) {
 970                 if (err == 0)
 971                         err = -EINVAL;
 972                 xenbus_dev_fatal(pdev->xdev, err,
 973                                  "Error reading number of PCI roots");
 974                 goto out;
 975         }
 976
 977         for (i = 0; i < num_roots; i++) {
 978                 len = snprintf(str, sizeof(str), "root-%d", i);
 979                 if (unlikely(len >= (sizeof(str) - 1))) {
 980                         err = -ENOMEM;
 981                         goto out;
 982                 }
 983
 984                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 985                                    "%x:%x", &domain, &bus);
 986                 if (err != 2) {
 987                         if (err >= 0)
 988                                 err = -EINVAL;
 989                         xenbus_dev_fatal(pdev->xdev, err,
 990                                          "Error reading PCI root %d", i);
 991                         goto out;
 992                 }
 993
 994                 err = pcifront_rescan_root(pdev, domain, bus);
 995                 if (err) {
 996                         xenbus_dev_fatal(pdev->xdev, err,
 997                                          "Error scanning PCI root %04x:%02x",
 998                                          domain, bus);
 999                         goto out;
1000                 }
1001         }
1002
1003         xenbus_switch_state(pdev->xdev, XenbusStateConnected);
1004
1005 out:
1006         return err;
1007 }
1008
1009 static int pcifront_detach_devices(struct pcifront_device *pdev)
1010 {
1011         int err = 0;
1012         int i, num_devs;
1013         unsigned int domain, bus, slot, func;
1014         struct pci_dev *pci_dev;
1015         char str[64];
1016
1017         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
1018             XenbusStateConnected)
1019                 goto out;
1020
1021         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d",
1022                            &num_devs);
1023         if (err != 1) {
1024                 if (err >= 0)
1025                         err = -EINVAL;
1026                 xenbus_dev_fatal(pdev->xdev, err,
1027                                  "Error reading number of PCI devices");
1028                 goto out;
1029         }
1030
1031         /* Find devices being detached and remove them. */
1032         for (i = 0; i < num_devs; i++) {
1033                 int l, state;
1034                 l = snprintf(str, sizeof(str), "state-%d", i);
1035                 if (unlikely(l >= (sizeof(str) - 1))) {
1036                         err = -ENOMEM;
1037                         goto out;
1038                 }
1039                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%d",
1040                                    &state);
1041                 if (err != 1)
1042                         state = XenbusStateUnknown;
1043
1044                 if (state != XenbusStateClosing)
1045                         continue;
1046
1047                 /* Remove device. */
1048                 l = snprintf(str, sizeof(str), "vdev-%d", i);
1049                 if (unlikely(l >= (sizeof(str) - 1))) {
1050                         err = -ENOMEM;
1051                         goto out;
1052                 }
1053                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
1054                                    "%x:%x:%x.%x", &domain, &bus, &slot, &func);
1055                 if (err != 4) {
1056                         if (err >= 0)
1057                                 err = -EINVAL;
1058                         xenbus_dev_fatal(pdev->xdev, err,
1059                                          "Error reading PCI device %d", i);
1060                         goto out;
1061                 }
1062
1063                 pci_dev = pci_get_domain_bus_and_slot(domain, bus,
1064                                 PCI_DEVFN(slot, func));
1065                 if (!pci_dev) {
1066                         dev_dbg(&pdev->xdev->dev,
1067                                 "Cannot get PCI device %04x:%02x:%02x.%d\n",
1068                                 domain, bus, slot, func);
1069                         continue;
1070                 }
1071                 pci_lock_rescan_remove();
1072                 pci_stop_and_remove_bus_device(pci_dev);
1073                 pci_dev_put(pci_dev);
1074                 pci_unlock_rescan_remove();
1075
1076                 dev_dbg(&pdev->xdev->dev,
1077                         "PCI device %04x:%02x:%02x.%d removed.\n",
1078                         domain, bus, slot, func);
1079         }
1080
1081         err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring);
1082
1083 out:
1084         return err;
1085 }
1086
1087 static void __init_refok pcifront_backend_changed(struct xenbus_device *xdev,
1088                                                   enum xenbus_state be_state)
1089 {
1090         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1091
1092         switch (be_state) {
1093         case XenbusStateUnknown:
1094         case XenbusStateInitialising:
1095         case XenbusStateInitWait:
1096         case XenbusStateInitialised:
1097                 break;
1098
1099         case XenbusStateConnected:
1100                 pcifront_try_connect(pdev);
1101                 break;
1102
1103         case XenbusStateClosed:
1104                 if (xdev->state == XenbusStateClosed)
1105                         break;
1106                 /* Missed the backend's CLOSING state -- fallthrough */
1107         case XenbusStateClosing:
1108                 dev_warn(&xdev->dev, "backend going away!\n");
1109                 pcifront_try_disconnect(pdev);
1110                 break;
1111
1112         case XenbusStateReconfiguring:
1113                 pcifront_detach_devices(pdev);
1114                 break;
1115
1116         case XenbusStateReconfigured:
1117                 pcifront_attach_devices(pdev);
1118                 break;
1119         }
1120 }
1121
1122 static int pcifront_xenbus_probe(struct xenbus_device *xdev,
1123                                  const struct xenbus_device_id *id)
1124 {
1125         int err = 0;
1126         struct pcifront_device *pdev = alloc_pdev(xdev);
1127
1128         if (pdev == NULL) {
1129                 err = -ENOMEM;
1130                 xenbus_dev_fatal(xdev, err,
1131                                  "Error allocating pcifront_device struct");
1132                 goto out;
1133         }
1134
1135         err = pcifront_publish_info(pdev);
1136         if (err)
1137                 free_pdev(pdev);
1138
1139 out:
1140         return err;
1141 }
1142
1143 static int pcifront_xenbus_remove(struct xenbus_device *xdev)
1144 {
1145         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1146         if (pdev)
1147                 free_pdev(pdev);
1148
1149         return 0;
1150 }
1151
1152 static const struct xenbus_device_id xenpci_ids[] = {
1153         {"pci"},
1154         {""},
1155 };
1156
1157 static struct xenbus_driver xenpci_driver = {
1158         .name                   = "pcifront",
1159         .ids                    = xenpci_ids,
1160         .probe                  = pcifront_xenbus_probe,
1161         .remove                 = pcifront_xenbus_remove,
1162         .otherend_changed       = pcifront_backend_changed,
1163 };
1164
1165 static int __init pcifront_init(void)
1166 {
1167         if (!xen_pv_domain() || xen_initial_domain())
1168                 return -ENODEV;
1169
1170         if (!xen_has_pv_devices())
1171                 return -ENODEV;
1172
1173         pci_frontend_registrar(1 /* enable */);
1174
1175         return xenbus_register_frontend(&xenpci_driver);
1176 }
1177
1178 static void __exit pcifront_cleanup(void)
1179 {
1180         xenbus_unregister_driver(&xenpci_driver);
1181         pci_frontend_registrar(0 /* disable */);
1182 }
1183 module_init(pcifront_init);
1184 module_exit(pcifront_cleanup);
1185
1186 MODULE_DESCRIPTION("Xen PCI passthrough frontend.");
1187 MODULE_LICENSE("GPL");
1188 MODULE_ALIAS("xen:pci");