drivers/pci/xen-pcifront.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Xen PCI Frontend.
   4  *
   5  *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
   6  */
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/mm.h>
  10 #include <xen/xenbus.h>
  11 #include <xen/events.h>
  12 #include <xen/grant_table.h>
  13 #include <xen/page.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/pci.h>
  16 #include <linux/msi.h>
  17 #include <xen/interface/io/pciif.h>
  18 #include <asm/xen/pci.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/atomic.h>
  21 #include <linux/workqueue.h>
  22 #include <linux/bitops.h>
  23 #include <linux/time.h>
  24 #include <linux/ktime.h>
  25 #include <xen/platform_pci.h>
  26
  27 #include <asm/xen/swiotlb-xen.h>
  28 #define INVALID_GRANT_REF (0)
  29 #define INVALID_EVTCHN    (-1)
  30
  31 struct pci_bus_entry {
  32         struct list_head list;
  33         struct pci_bus *bus;
  34 };
  35
  36 #define _PDEVB_op_active                (0)
  37 #define PDEVB_op_active                 (1 << (_PDEVB_op_active))
  38
  39 struct pcifront_device {
  40         struct xenbus_device *xdev;
  41         struct list_head root_buses;
  42
  43         int evtchn;
  44         int gnt_ref;
  45
  46         int irq;
  47
  48         /* Lock this when doing any operations in sh_info */
  49         spinlock_t sh_info_lock;
  50         struct xen_pci_sharedinfo *sh_info;
  51         struct work_struct op_work;
  52         unsigned long flags;
  53
  54 };
  55
  56 struct pcifront_sd {
  57         struct pci_sysdata sd;
  58         struct pcifront_device *pdev;
  59 };
  60
  61 static inline struct pcifront_device *
  62 pcifront_get_pdev(struct pcifront_sd *sd)
  63 {
  64         return sd->pdev;
  65 }
  66
  67 static inline void pcifront_init_sd(struct pcifront_sd *sd,
  68                                     unsigned int domain, unsigned int bus,
  69                                     struct pcifront_device *pdev)
  70 {
  71         /* Because we do not expose that information via XenBus. */
  72         sd->sd.node = first_online_node;
  73         sd->sd.domain = domain;
  74         sd->pdev = pdev;
  75 }
  76
  77 static DEFINE_SPINLOCK(pcifront_dev_lock);
  78 static struct pcifront_device *pcifront_dev;
  79
  80 static int verbose_request;
  81 module_param(verbose_request, int, 0644);
  82
  83 static int errno_to_pcibios_err(int errno)
  84 {
  85         switch (errno) {
  86         case XEN_PCI_ERR_success:
  87                 return PCIBIOS_SUCCESSFUL;
  88
  89         case XEN_PCI_ERR_dev_not_found:
  90                 return PCIBIOS_DEVICE_NOT_FOUND;
  91
  92         case XEN_PCI_ERR_invalid_offset:
  93         case XEN_PCI_ERR_op_failed:
  94                 return PCIBIOS_BAD_REGISTER_NUMBER;
  95
  96         case XEN_PCI_ERR_not_implemented:
  97                 return PCIBIOS_FUNC_NOT_SUPPORTED;
  98
  99         case XEN_PCI_ERR_access_denied:
 100                 return PCIBIOS_SET_FAILED;
 101         }
 102         return errno;
 103 }
 104
 105 static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev)
 106 {
 107         if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
 108                 && !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) {
 109                 dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n");
 110                 schedule_work(&pdev->op_work);
 111         }
 112 }
 113
 114 static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 115 {
 116         int err = 0;
 117         struct xen_pci_op *active_op = &pdev->sh_info->op;
 118         unsigned long irq_flags;
 119         evtchn_port_t port = pdev->evtchn;
 120         unsigned irq = pdev->irq;
 121         s64 ns, ns_timeout;
 122
 123         spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
 124
 125         memcpy(active_op, op, sizeof(struct xen_pci_op));
 126
 127         /* Go */
 128         wmb();
 129         set_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
 130         notify_remote_via_evtchn(port);
 131
 132         /*
 133          * We set a poll timeout of 3 seconds but give up on return after
 134          * 2 seconds. It is better to time out too late rather than too early
 135          * (in the latter case we end up continually re-executing poll() with a
 136          * timeout in the past). 1s difference gives plenty of slack for error.
 137          */
 138         ns_timeout = ktime_get_ns() + 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                 ns = ktime_get_ns();
 147                 if (ns > ns_timeout) {
 148                         dev_err(&pdev->xdev->dev,
 149                                 "pciback not responding!!!\n");
 150                         clear_bit(_XEN_PCIF_active,
 151                                   (unsigned long *)&pdev->sh_info->flags);
 152                         err = XEN_PCI_ERR_dev_not_found;
 153                         goto out;
 154                 }
 155         }
 156
 157         /*
 158         * We might lose backend service request since we
 159         * reuse same evtchn with pci_conf backend response. So re-schedule
 160         * aer pcifront service.
 161         */
 162         if (test_bit(_XEN_PCIB_active,
 163                         (unsigned long *)&pdev->sh_info->flags)) {
 164                 dev_err(&pdev->xdev->dev,
 165                         "schedule aer pcifront service\n");
 166                 schedule_pcifront_aer_op(pdev);
 167         }
 168
 169         memcpy(op, active_op, sizeof(struct xen_pci_op));
 170
 171         err = op->err;
 172 out:
 173         spin_unlock_irqrestore(&pdev->sh_info_lock, irq_flags);
 174         return err;
 175 }
 176
 177 /* Access to this function is spinlocked in drivers/pci/access.c */
 178 static int pcifront_bus_read(struct pci_bus *bus, unsigned int devfn,
 179                              int where, int size, u32 *val)
 180 {
 181         int err = 0;
 182         struct xen_pci_op op = {
 183                 .cmd    = XEN_PCI_OP_conf_read,
 184                 .domain = pci_domain_nr(bus),
 185                 .bus    = bus->number,
 186                 .devfn  = devfn,
 187                 .offset = where,
 188                 .size   = size,
 189         };
 190         struct pcifront_sd *sd = bus->sysdata;
 191         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 192
 193         if (verbose_request)
 194                 dev_info(&pdev->xdev->dev,
 195                          "read dev=%04x:%02x:%02x.%d - offset %x size %d\n",
 196                          pci_domain_nr(bus), bus->number, PCI_SLOT(devfn),
 197                          PCI_FUNC(devfn), where, size);
 198
 199         err = do_pci_op(pdev, &op);
 200
 201         if (likely(!err)) {
 202                 if (verbose_request)
 203                         dev_info(&pdev->xdev->dev, "read got back value %x\n",
 204                                  op.value);
 205
 206                 *val = op.value;
 207         } else if (err == -ENODEV) {
 208                 /* No device here, pretend that it just returned 0 */
 209                 err = 0;
 210                 *val = 0;
 211         }
 212
 213         return errno_to_pcibios_err(err);
 214 }
 215
 216 /* Access to this function is spinlocked in drivers/pci/access.c */
 217 static int pcifront_bus_write(struct pci_bus *bus, unsigned int devfn,
 218                               int where, int size, u32 val)
 219 {
 220         struct xen_pci_op op = {
 221                 .cmd    = XEN_PCI_OP_conf_write,
 222                 .domain = pci_domain_nr(bus),
 223                 .bus    = bus->number,
 224                 .devfn  = devfn,
 225                 .offset = where,
 226                 .size   = size,
 227                 .value  = val,
 228         };
 229         struct pcifront_sd *sd = bus->sysdata;
 230         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 231
 232         if (verbose_request)
 233                 dev_info(&pdev->xdev->dev,
 234                          "write dev=%04x:%02x:%02x.%d - "
 235                          "offset %x size %d val %x\n",
 236                          pci_domain_nr(bus), bus->number,
 237                          PCI_SLOT(devfn), PCI_FUNC(devfn), where, size, val);
 238
 239         return errno_to_pcibios_err(do_pci_op(pdev, &op));
 240 }
 241
 242 static struct pci_ops pcifront_bus_ops = {
 243         .read = pcifront_bus_read,
 244         .write = pcifront_bus_write,
 245 };
 246
 247 #ifdef CONFIG_PCI_MSI
 248 static int pci_frontend_enable_msix(struct pci_dev *dev,
 249                                     int vector[], int nvec)
 250 {
 251         int err;
 252         int i;
 253         struct xen_pci_op op = {
 254                 .cmd    = XEN_PCI_OP_enable_msix,
 255                 .domain = pci_domain_nr(dev->bus),
 256                 .bus = dev->bus->number,
 257                 .devfn = dev->devfn,
 258                 .value = nvec,
 259         };
 260         struct pcifront_sd *sd = dev->bus->sysdata;
 261         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 262         struct msi_desc *entry;
 263
 264         if (nvec > SH_INFO_MAX_VEC) {
 265                 pci_err(dev, "too many vectors (0x%x) for PCI frontend:"
 266                                    " Increase SH_INFO_MAX_VEC\n", nvec);
 267                 return -EINVAL;
 268         }
 269
 270         i = 0;
 271         for_each_pci_msi_entry(entry, dev) {
 272                 op.msix_entries[i].entry = entry->msi_attrib.entry_nr;
 273                 /* Vector is useless at this point. */
 274                 op.msix_entries[i].vector = -1;
 275                 i++;
 276         }
 277
 278         err = do_pci_op(pdev, &op);
 279
 280         if (likely(!err)) {
 281                 if (likely(!op.value)) {
 282                         /* we get the result */
 283                         for (i = 0; i < nvec; i++) {
 284                                 if (op.msix_entries[i].vector <= 0) {
 285                                         pci_warn(dev, "MSI-X entry %d is invalid: %d!\n",
 286                                                 i, op.msix_entries[i].vector);
 287                                         err = -EINVAL;
 288                                         vector[i] = -1;
 289                                         continue;
 290                                 }
 291                                 vector[i] = op.msix_entries[i].vector;
 292                         }
 293                 } else {
 294                         printk(KERN_DEBUG "enable msix get value %x\n",
 295                                 op.value);
 296                         err = op.value;
 297                 }
 298         } else {
 299                 pci_err(dev, "enable msix get err %x\n", err);
 300         }
 301         return err;
 302 }
 303
 304 static void pci_frontend_disable_msix(struct pci_dev *dev)
 305 {
 306         int err;
 307         struct xen_pci_op op = {
 308                 .cmd    = XEN_PCI_OP_disable_msix,
 309                 .domain = pci_domain_nr(dev->bus),
 310                 .bus = dev->bus->number,
 311                 .devfn = dev->devfn,
 312         };
 313         struct pcifront_sd *sd = dev->bus->sysdata;
 314         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 315
 316         err = do_pci_op(pdev, &op);
 317
 318         /* What should do for error ? */
 319         if (err)
 320                 pci_err(dev, "pci_disable_msix get err %x\n", err);
 321 }
 322
 323 static int pci_frontend_enable_msi(struct pci_dev *dev, int vector[])
 324 {
 325         int err;
 326         struct xen_pci_op op = {
 327                 .cmd    = XEN_PCI_OP_enable_msi,
 328                 .domain = pci_domain_nr(dev->bus),
 329                 .bus = dev->bus->number,
 330                 .devfn = dev->devfn,
 331         };
 332         struct pcifront_sd *sd = dev->bus->sysdata;
 333         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 334
 335         err = do_pci_op(pdev, &op);
 336         if (likely(!err)) {
 337                 vector[0] = op.value;
 338                 if (op.value <= 0) {
 339                         pci_warn(dev, "MSI entry is invalid: %d!\n",
 340                                 op.value);
 341                         err = -EINVAL;
 342                         vector[0] = -1;
 343                 }
 344         } else {
 345                 pci_err(dev, "pci frontend enable msi failed for dev "
 346                                     "%x:%x\n", op.bus, op.devfn);
 347                 err = -EINVAL;
 348         }
 349         return err;
 350 }
 351
 352 static void pci_frontend_disable_msi(struct pci_dev *dev)
 353 {
 354         int err;
 355         struct xen_pci_op op = {
 356                 .cmd    = XEN_PCI_OP_disable_msi,
 357                 .domain = pci_domain_nr(dev->bus),
 358                 .bus = dev->bus->number,
 359                 .devfn = dev->devfn,
 360         };
 361         struct pcifront_sd *sd = dev->bus->sysdata;
 362         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 363
 364         err = do_pci_op(pdev, &op);
 365         if (err == XEN_PCI_ERR_dev_not_found) {
 366                 /* XXX No response from backend, what shall we do? */
 367                 printk(KERN_DEBUG "get no response from backend for disable MSI\n");
 368                 return;
 369         }
 370         if (err)
 371                 /* how can pciback notify us fail? */
 372                 printk(KERN_DEBUG "get fake response frombackend\n");
 373 }
 374
 375 static struct xen_pci_frontend_ops pci_frontend_ops = {
 376         .enable_msi = pci_frontend_enable_msi,
 377         .disable_msi = pci_frontend_disable_msi,
 378         .enable_msix = pci_frontend_enable_msix,
 379         .disable_msix = pci_frontend_disable_msix,
 380 };
 381
 382 static void pci_frontend_registrar(int enable)
 383 {
 384         if (enable)
 385                 xen_pci_frontend = &pci_frontend_ops;
 386         else
 387                 xen_pci_frontend = NULL;
 388 };
 389 #else
 390 static inline void pci_frontend_registrar(int enable) { };
 391 #endif /* CONFIG_PCI_MSI */
 392
 393 /* Claim resources for the PCI frontend as-is, backend won't allow changes */
 394 static int pcifront_claim_resource(struct pci_dev *dev, void *data)
 395 {
 396         struct pcifront_device *pdev = data;
 397         int i;
 398         struct resource *r;
 399
 400         for (i = 0; i < PCI_NUM_RESOURCES; i++) {
 401                 r = &dev->resource[i];
 402
 403                 if (!r->parent && r->start && r->flags) {
 404                         dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n",
 405                                 pci_name(dev), i);
 406                         if (pci_claim_resource(dev, i)) {
 407                                 dev_err(&pdev->xdev->dev, "Could not claim resource %s/%d! "
 408                                         "Device offline. Try using e820_host=1 in the guest config.\n",
 409                                         pci_name(dev), i);
 410                         }
 411                 }
 412         }
 413
 414         return 0;
 415 }
 416
 417 static int pcifront_scan_bus(struct pcifront_device *pdev,
 418                                 unsigned int domain, unsigned int bus,
 419                                 struct pci_bus *b)
 420 {
 421         struct pci_dev *d;
 422         unsigned int devfn;
 423
 424         /* Scan the bus for functions and add.
 425          * We omit handling of PCI bridge attachment because pciback prevents
 426          * bridges from being exported.
 427          */
 428         for (devfn = 0; devfn < 0x100; devfn++) {
 429                 d = pci_get_slot(b, devfn);
 430                 if (d) {
 431                         /* Device is already known. */
 432                         pci_dev_put(d);
 433                         continue;
 434                 }
 435
 436                 d = pci_scan_single_device(b, devfn);
 437                 if (d)
 438                         dev_info(&pdev->xdev->dev, "New device on "
 439                                  "%04x:%02x:%02x.%d found.\n", domain, bus,
 440                                  PCI_SLOT(devfn), PCI_FUNC(devfn));
 441         }
 442
 443         return 0;
 444 }
 445
 446 static int pcifront_scan_root(struct pcifront_device *pdev,
 447                                  unsigned int domain, unsigned int bus)
 448 {
 449         struct pci_bus *b;
 450         LIST_HEAD(resources);
 451         struct pcifront_sd *sd = NULL;
 452         struct pci_bus_entry *bus_entry = NULL;
 453         int err = 0;
 454         static struct resource busn_res = {
 455                 .start = 0,
 456                 .end = 255,
 457                 .flags = IORESOURCE_BUS,
 458         };
 459
 460 #ifndef CONFIG_PCI_DOMAINS
 461         if (domain != 0) {
 462                 dev_err(&pdev->xdev->dev,
 463                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 464                 dev_err(&pdev->xdev->dev,
 465                         "Please compile with CONFIG_PCI_DOMAINS\n");
 466                 err = -EINVAL;
 467                 goto err_out;
 468         }
 469 #endif
 470
 471         dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n",
 472                  domain, bus);
 473
 474         bus_entry = kzalloc(sizeof(*bus_entry), GFP_KERNEL);
 475         sd = kzalloc(sizeof(*sd), GFP_KERNEL);
 476         if (!bus_entry || !sd) {
 477                 err = -ENOMEM;
 478                 goto err_out;
 479         }
 480         pci_add_resource(&resources, &ioport_resource);
 481         pci_add_resource(&resources, &iomem_resource);
 482         pci_add_resource(&resources, &busn_res);
 483         pcifront_init_sd(sd, domain, bus, pdev);
 484
 485         pci_lock_rescan_remove();
 486
 487         b = pci_scan_root_bus(&pdev->xdev->dev, bus,
 488                                   &pcifront_bus_ops, sd, &resources);
 489         if (!b) {
 490                 dev_err(&pdev->xdev->dev,
 491                         "Error creating PCI Frontend Bus!\n");
 492                 err = -ENOMEM;
 493                 pci_unlock_rescan_remove();
 494                 pci_free_resource_list(&resources);
 495                 goto err_out;
 496         }
 497
 498         bus_entry->bus = b;
 499
 500         list_add(&bus_entry->list, &pdev->root_buses);
 501
 502         /* pci_scan_root_bus skips devices which do not have a
 503         * devfn==0. The pcifront_scan_bus enumerates all devfn. */
 504         err = pcifront_scan_bus(pdev, domain, bus, b);
 505
 506         /* Claim resources before going "live" with our devices */
 507         pci_walk_bus(b, pcifront_claim_resource, pdev);
 508
 509         /* Create SysFS and notify udev of the devices. Aka: "going live" */
 510         pci_bus_add_devices(b);
 511
 512         pci_unlock_rescan_remove();
 513         return err;
 514
 515 err_out:
 516         kfree(bus_entry);
 517         kfree(sd);
 518
 519         return err;
 520 }
 521
 522 static int pcifront_rescan_root(struct pcifront_device *pdev,
 523                                    unsigned int domain, unsigned int bus)
 524 {
 525         int err;
 526         struct pci_bus *b;
 527
 528 #ifndef CONFIG_PCI_DOMAINS
 529         if (domain != 0) {
 530                 dev_err(&pdev->xdev->dev,
 531                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 532                 dev_err(&pdev->xdev->dev,
 533                         "Please compile with CONFIG_PCI_DOMAINS\n");
 534                 return -EINVAL;
 535         }
 536 #endif
 537
 538         dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
 539                  domain, bus);
 540
 541         b = pci_find_bus(domain, bus);
 542         if (!b)
 543                 /* If the bus is unknown, create it. */
 544                 return pcifront_scan_root(pdev, domain, bus);
 545
 546         err = pcifront_scan_bus(pdev, domain, bus, b);
 547
 548         /* Claim resources before going "live" with our devices */
 549         pci_walk_bus(b, pcifront_claim_resource, pdev);
 550
 551         /* Create SysFS and notify udev of the devices. Aka: "going live" */
 552         pci_bus_add_devices(b);
 553
 554         return err;
 555 }
 556
 557 static void free_root_bus_devs(struct pci_bus *bus)
 558 {
 559         struct pci_dev *dev;
 560
 561         while (!list_empty(&bus->devices)) {
 562                 dev = container_of(bus->devices.next, struct pci_dev,
 563                                    bus_list);
 564                 pci_dbg(dev, "removing device\n");
 565                 pci_stop_and_remove_bus_device(dev);
 566         }
 567 }
 568
 569 static void pcifront_free_roots(struct pcifront_device *pdev)
 570 {
 571         struct pci_bus_entry *bus_entry, *t;
 572
 573         dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n");
 574
 575         pci_lock_rescan_remove();
 576         list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) {
 577                 list_del(&bus_entry->list);
 578
 579                 free_root_bus_devs(bus_entry->bus);
 580
 581                 kfree(bus_entry->bus->sysdata);
 582
 583                 device_unregister(bus_entry->bus->bridge);
 584                 pci_remove_bus(bus_entry->bus);
 585
 586                 kfree(bus_entry);
 587         }
 588         pci_unlock_rescan_remove();
 589 }
 590
 591 static pci_ers_result_t pcifront_common_process(int cmd,
 592                                                 struct pcifront_device *pdev,
 593                                                 pci_channel_state_t state)
 594 {
 595         pci_ers_result_t result;
 596         struct pci_driver *pdrv;
 597         int bus = pdev->sh_info->aer_op.bus;
 598         int devfn = pdev->sh_info->aer_op.devfn;
 599         int domain = pdev->sh_info->aer_op.domain;
 600         struct pci_dev *pcidev;
 601         int flag = 0;
 602
 603         dev_dbg(&pdev->xdev->dev,
 604                 "pcifront AER process: cmd %x (bus:%x, devfn%x)",
 605                 cmd, bus, devfn);
 606         result = PCI_ERS_RESULT_NONE;
 607
 608         pcidev = pci_get_domain_bus_and_slot(domain, bus, devfn);
 609         if (!pcidev || !pcidev->driver) {
 610                 dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
 611                 pci_dev_put(pcidev);
 612                 return result;
 613         }
 614         pdrv = pcidev->driver;
 615
 616         if (pdrv) {
 617                 if (pdrv->err_handler && pdrv->err_handler->error_detected) {
 618                         pci_dbg(pcidev, "trying to call AER service\n");
 619                         if (pcidev) {
 620                                 flag = 1;
 621                                 switch (cmd) {
 622                                 case XEN_PCI_OP_aer_detected:
 623                                         result = pdrv->err_handler->
 624                                                  error_detected(pcidev, state);
 625                                         break;
 626                                 case XEN_PCI_OP_aer_mmio:
 627                                         result = pdrv->err_handler->
 628                                                  mmio_enabled(pcidev);
 629                                         break;
 630                                 case XEN_PCI_OP_aer_slotreset:
 631                                         result = pdrv->err_handler->
 632                                                  slot_reset(pcidev);
 633                                         break;
 634                                 case XEN_PCI_OP_aer_resume:
 635                                         pdrv->err_handler->resume(pcidev);
 636                                         break;
 637                                 default:
 638                                         dev_err(&pdev->xdev->dev,
 639                                                 "bad request in aer recovery "
 640                                                 "operation!\n");
 641
 642                                 }
 643                         }
 644                 }
 645         }
 646         if (!flag)
 647                 result = PCI_ERS_RESULT_NONE;
 648
 649         return result;
 650 }
 651
 652
 653 static void pcifront_do_aer(struct work_struct *data)
 654 {
 655         struct pcifront_device *pdev =
 656                 container_of(data, struct pcifront_device, op_work);
 657         int cmd = pdev->sh_info->aer_op.cmd;
 658         pci_channel_state_t state =
 659                 (pci_channel_state_t)pdev->sh_info->aer_op.err;
 660
 661         /*If a pci_conf op is in progress,
 662                 we have to wait until it is done before service aer op*/
 663         dev_dbg(&pdev->xdev->dev,
 664                 "pcifront service aer bus %x devfn %x\n",
 665                 pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn);
 666
 667         pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state);
 668
 669         /* Post the operation to the guest. */
 670         wmb();
 671         clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags);
 672         notify_remote_via_evtchn(pdev->evtchn);
 673
 674         /*in case of we lost an aer request in four lines time_window*/
 675         smp_mb__before_atomic();
 676         clear_bit(_PDEVB_op_active, &pdev->flags);
 677         smp_mb__after_atomic();
 678
 679         schedule_pcifront_aer_op(pdev);
 680
 681 }
 682
 683 static irqreturn_t pcifront_handler_aer(int irq, void *dev)
 684 {
 685         struct pcifront_device *pdev = dev;
 686         schedule_pcifront_aer_op(pdev);
 687         return IRQ_HANDLED;
 688 }
 689 static int pcifront_connect_and_init_dma(struct pcifront_device *pdev)
 690 {
 691         int err = 0;
 692
 693         spin_lock(&pcifront_dev_lock);
 694
 695         if (!pcifront_dev) {
 696                 dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
 697                 pcifront_dev = pdev;
 698         } else
 699                 err = -EEXIST;
 700
 701         spin_unlock(&pcifront_dev_lock);
 702
 703         if (!err && !swiotlb_nr_tbl()) {
 704                 err = pci_xen_swiotlb_init_late();
 705                 if (err)
 706                         dev_err(&pdev->xdev->dev, "Could not setup SWIOTLB!\n");
 707         }
 708         return err;
 709 }
 710
 711 static void pcifront_disconnect(struct pcifront_device *pdev)
 712 {
 713         spin_lock(&pcifront_dev_lock);
 714
 715         if (pdev == pcifront_dev) {
 716                 dev_info(&pdev->xdev->dev,
 717                          "Disconnecting PCI Frontend Buses\n");
 718                 pcifront_dev = NULL;
 719         }
 720
 721         spin_unlock(&pcifront_dev_lock);
 722 }
 723 static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev)
 724 {
 725         struct pcifront_device *pdev;
 726
 727         pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL);
 728         if (pdev == NULL)
 729                 goto out;
 730
 731         pdev->sh_info =
 732             (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL);
 733         if (pdev->sh_info == NULL) {
 734                 kfree(pdev);
 735                 pdev = NULL;
 736                 goto out;
 737         }
 738         pdev->sh_info->flags = 0;
 739
 740         /*Flag for registering PV AER handler*/
 741         set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags);
 742
 743         dev_set_drvdata(&xdev->dev, pdev);
 744         pdev->xdev = xdev;
 745
 746         INIT_LIST_HEAD(&pdev->root_buses);
 747
 748         spin_lock_init(&pdev->sh_info_lock);
 749
 750         pdev->evtchn = INVALID_EVTCHN;
 751         pdev->gnt_ref = INVALID_GRANT_REF;
 752         pdev->irq = -1;
 753
 754         INIT_WORK(&pdev->op_work, pcifront_do_aer);
 755
 756         dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n",
 757                 pdev, pdev->sh_info);
 758 out:
 759         return pdev;
 760 }
 761
 762 static void free_pdev(struct pcifront_device *pdev)
 763 {
 764         dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
 765
 766         pcifront_free_roots(pdev);
 767
 768         cancel_work_sync(&pdev->op_work);
 769
 770         if (pdev->irq >= 0)
 771                 unbind_from_irqhandler(pdev->irq, pdev);
 772
 773         if (pdev->evtchn != INVALID_EVTCHN)
 774                 xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
 775
 776         if (pdev->gnt_ref != INVALID_GRANT_REF)
 777                 gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
 778                                           (unsigned long)pdev->sh_info);
 779         else
 780                 free_page((unsigned long)pdev->sh_info);
 781
 782         dev_set_drvdata(&pdev->xdev->dev, NULL);
 783
 784         kfree(pdev);
 785 }
 786
 787 static int pcifront_publish_info(struct pcifront_device *pdev)
 788 {
 789         int err = 0;
 790         struct xenbus_transaction trans;
 791         grant_ref_t gref;
 792
 793         err = xenbus_grant_ring(pdev->xdev, pdev->sh_info, 1, &gref);
 794         if (err < 0)
 795                 goto out;
 796
 797         pdev->gnt_ref = gref;
 798
 799         err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
 800         if (err)
 801                 goto out;
 802
 803         err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer,
 804                 0, "pcifront", pdev);
 805
 806         if (err < 0)
 807                 return err;
 808
 809         pdev->irq = err;
 810
 811 do_publish:
 812         err = xenbus_transaction_start(&trans);
 813         if (err) {
 814                 xenbus_dev_fatal(pdev->xdev, err,
 815                                  "Error writing configuration for backend "
 816                                  "(start transaction)");
 817                 goto out;
 818         }
 819
 820         err = xenbus_printf(trans, pdev->xdev->nodename,
 821                             "pci-op-ref", "%u", pdev->gnt_ref);
 822         if (!err)
 823                 err = xenbus_printf(trans, pdev->xdev->nodename,
 824                                     "event-channel", "%u", pdev->evtchn);
 825         if (!err)
 826                 err = xenbus_printf(trans, pdev->xdev->nodename,
 827                                     "magic", XEN_PCI_MAGIC);
 828
 829         if (err) {
 830                 xenbus_transaction_end(trans, 1);
 831                 xenbus_dev_fatal(pdev->xdev, err,
 832                                  "Error writing configuration for backend");
 833                 goto out;
 834         } else {
 835                 err = xenbus_transaction_end(trans, 0);
 836                 if (err == -EAGAIN)
 837                         goto do_publish;
 838                 else if (err) {
 839                         xenbus_dev_fatal(pdev->xdev, err,
 840                                          "Error completing transaction "
 841                                          "for backend");
 842                         goto out;
 843                 }
 844         }
 845
 846         xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
 847
 848         dev_dbg(&pdev->xdev->dev, "publishing successful!\n");
 849
 850 out:
 851         return err;
 852 }
 853
 854 static int pcifront_try_connect(struct pcifront_device *pdev)
 855 {
 856         int err = -EFAULT;
 857         int i, num_roots, len;
 858         char str[64];
 859         unsigned int domain, bus;
 860
 861
 862         /* Only connect once */
 863         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 864             XenbusStateInitialised)
 865                 goto out;
 866
 867         err = pcifront_connect_and_init_dma(pdev);
 868         if (err && err != -EEXIST) {
 869                 xenbus_dev_fatal(pdev->xdev, err,
 870                                  "Error setting up PCI Frontend");
 871                 goto out;
 872         }
 873
 874         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 875                            "root_num", "%d", &num_roots);
 876         if (err == -ENOENT) {
 877                 xenbus_dev_error(pdev->xdev, err,
 878                                  "No PCI Roots found, trying 0000:00");
 879                 err = pcifront_scan_root(pdev, 0, 0);
 880                 if (err) {
 881                         xenbus_dev_fatal(pdev->xdev, err,
 882                                          "Error scanning PCI root 0000:00");
 883                         goto out;
 884                 }
 885                 num_roots = 0;
 886         } else if (err != 1) {
 887                 if (err == 0)
 888                         err = -EINVAL;
 889                 xenbus_dev_fatal(pdev->xdev, err,
 890                                  "Error reading number of PCI roots");
 891                 goto out;
 892         }
 893
 894         for (i = 0; i < num_roots; i++) {
 895                 len = snprintf(str, sizeof(str), "root-%d", i);
 896                 if (unlikely(len >= (sizeof(str) - 1))) {
 897                         err = -ENOMEM;
 898                         goto out;
 899                 }
 900
 901                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 902                                    "%x:%x", &domain, &bus);
 903                 if (err != 2) {
 904                         if (err >= 0)
 905                                 err = -EINVAL;
 906                         xenbus_dev_fatal(pdev->xdev, err,
 907                                          "Error reading PCI root %d", i);
 908                         goto out;
 909                 }
 910
 911                 err = pcifront_scan_root(pdev, domain, bus);
 912                 if (err) {
 913                         xenbus_dev_fatal(pdev->xdev, err,
 914                                          "Error scanning PCI root %04x:%02x",
 915                                          domain, bus);
 916                         goto out;
 917                 }
 918         }
 919
 920         err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 921
 922 out:
 923         return err;
 924 }
 925
 926 static int pcifront_try_disconnect(struct pcifront_device *pdev)
 927 {
 928         int err = 0;
 929         enum xenbus_state prev_state;
 930
 931
 932         prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
 933
 934         if (prev_state >= XenbusStateClosing)
 935                 goto out;
 936
 937         if (prev_state == XenbusStateConnected) {
 938                 pcifront_free_roots(pdev);
 939                 pcifront_disconnect(pdev);
 940         }
 941
 942         err = xenbus_switch_state(pdev->xdev, XenbusStateClosed);
 943
 944 out:
 945
 946         return err;
 947 }
 948
 949 static int pcifront_attach_devices(struct pcifront_device *pdev)
 950 {
 951         int err = -EFAULT;
 952         int i, num_roots, len;
 953         unsigned int domain, bus;
 954         char str[64];
 955
 956         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 957             XenbusStateReconfiguring)
 958                 goto out;
 959
 960         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 961                            "root_num", "%d", &num_roots);
 962         if (err == -ENOENT) {
 963                 xenbus_dev_error(pdev->xdev, err,
 964                                  "No PCI Roots found, trying 0000:00");
 965                 err = pcifront_rescan_root(pdev, 0, 0);
 966                 if (err) {
 967                         xenbus_dev_fatal(pdev->xdev, err,
 968                                          "Error scanning PCI root 0000:00");
 969                         goto out;
 970                 }
 971                 num_roots = 0;
 972         } else if (err != 1) {
 973                 if (err == 0)
 974                         err = -EINVAL;
 975                 xenbus_dev_fatal(pdev->xdev, err,
 976                                  "Error reading number of PCI roots");
 977                 goto out;
 978         }
 979
 980         for (i = 0; i < num_roots; i++) {
 981                 len = snprintf(str, sizeof(str), "root-%d", i);
 982                 if (unlikely(len >= (sizeof(str) - 1))) {
 983                         err = -ENOMEM;
 984                         goto out;
 985                 }
 986
 987                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 988                                    "%x:%x", &domain, &bus);
 989                 if (err != 2) {
 990                         if (err >= 0)
 991                                 err = -EINVAL;
 992                         xenbus_dev_fatal(pdev->xdev, err,
 993                                          "Error reading PCI root %d", i);
 994                         goto out;
 995                 }
 996
 997                 err = pcifront_rescan_root(pdev, domain, bus);
 998                 if (err) {
 999                         xenbus_dev_fatal(pdev->xdev, err,
1000                                          "Error scanning PCI root %04x:%02x",
1001                                          domain, bus);
1002                         goto out;
1003                 }
1004         }
1005
1006         xenbus_switch_state(pdev->xdev, XenbusStateConnected);
1007
1008 out:
1009         return err;
1010 }
1011
1012 static int pcifront_detach_devices(struct pcifront_device *pdev)
1013 {
1014         int err = 0;
1015         int i, num_devs;
1016         unsigned int domain, bus, slot, func;
1017         struct pci_dev *pci_dev;
1018         char str[64];
1019
1020         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
1021             XenbusStateConnected)
1022                 goto out;
1023
1024         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d",
1025                            &num_devs);
1026         if (err != 1) {
1027                 if (err >= 0)
1028                         err = -EINVAL;
1029                 xenbus_dev_fatal(pdev->xdev, err,
1030                                  "Error reading number of PCI devices");
1031                 goto out;
1032         }
1033
1034         /* Find devices being detached and remove them. */
1035         for (i = 0; i < num_devs; i++) {
1036                 int l, state;
1037                 l = snprintf(str, sizeof(str), "state-%d", i);
1038                 if (unlikely(l >= (sizeof(str) - 1))) {
1039                         err = -ENOMEM;
1040                         goto out;
1041                 }
1042                 state = xenbus_read_unsigned(pdev->xdev->otherend, str,
1043                                              XenbusStateUnknown);
1044
1045                 if (state != XenbusStateClosing)
1046                         continue;
1047
1048                 /* Remove device. */
1049                 l = snprintf(str, sizeof(str), "vdev-%d", i);
1050                 if (unlikely(l >= (sizeof(str) - 1))) {
1051                         err = -ENOMEM;
1052                         goto out;
1053                 }
1054                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
1055                                    "%x:%x:%x.%x", &domain, &bus, &slot, &func);
1056                 if (err != 4) {
1057                         if (err >= 0)
1058                                 err = -EINVAL;
1059                         xenbus_dev_fatal(pdev->xdev, err,
1060                                          "Error reading PCI device %d", i);
1061                         goto out;
1062                 }
1063
1064                 pci_dev = pci_get_domain_bus_and_slot(domain, bus,
1065                                 PCI_DEVFN(slot, func));
1066                 if (!pci_dev) {
1067                         dev_dbg(&pdev->xdev->dev,
1068                                 "Cannot get PCI device %04x:%02x:%02x.%d\n",
1069                                 domain, bus, slot, func);
1070                         continue;
1071                 }
1072                 pci_lock_rescan_remove();
1073                 pci_stop_and_remove_bus_device(pci_dev);
1074                 pci_dev_put(pci_dev);
1075                 pci_unlock_rescan_remove();
1076
1077                 dev_dbg(&pdev->xdev->dev,
1078                         "PCI device %04x:%02x:%02x.%d removed.\n",
1079                         domain, bus, slot, func);
1080         }
1081
1082         err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring);
1083
1084 out:
1085         return err;
1086 }
1087
1088 static void __ref pcifront_backend_changed(struct xenbus_device *xdev,
1089                                                   enum xenbus_state be_state)
1090 {
1091         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1092
1093         switch (be_state) {
1094         case XenbusStateUnknown:
1095         case XenbusStateInitialising:
1096         case XenbusStateInitWait:
1097         case XenbusStateInitialised:
1098                 break;
1099
1100         case XenbusStateConnected:
1101                 pcifront_try_connect(pdev);
1102                 break;
1103
1104         case XenbusStateClosed:
1105                 if (xdev->state == XenbusStateClosed)
1106                         break;
1107                 /* Missed the backend's CLOSING state -- fallthrough */
1108         case XenbusStateClosing:
1109                 dev_warn(&xdev->dev, "backend going away!\n");
1110                 pcifront_try_disconnect(pdev);
1111                 break;
1112
1113         case XenbusStateReconfiguring:
1114                 pcifront_detach_devices(pdev);
1115                 break;
1116
1117         case XenbusStateReconfigured:
1118                 pcifront_attach_devices(pdev);
1119                 break;
1120         }
1121 }
1122
1123 static int pcifront_xenbus_probe(struct xenbus_device *xdev,
1124                                  const struct xenbus_device_id *id)
1125 {
1126         int err = 0;
1127         struct pcifront_device *pdev = alloc_pdev(xdev);
1128
1129         if (pdev == NULL) {
1130                 err = -ENOMEM;
1131                 xenbus_dev_fatal(xdev, err,
1132                                  "Error allocating pcifront_device struct");
1133                 goto out;
1134         }
1135
1136         err = pcifront_publish_info(pdev);
1137         if (err)
1138                 free_pdev(pdev);
1139
1140 out:
1141         return err;
1142 }
1143
1144 static int pcifront_xenbus_remove(struct xenbus_device *xdev)
1145 {
1146         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1147         if (pdev)
1148                 free_pdev(pdev);
1149
1150         return 0;
1151 }
1152
1153 static const struct xenbus_device_id xenpci_ids[] = {
1154         {"pci"},
1155         {""},
1156 };
1157
1158 static struct xenbus_driver xenpci_driver = {
1159         .name                   = "pcifront",
1160         .ids                    = xenpci_ids,
1161         .probe                  = pcifront_xenbus_probe,
1162         .remove                 = pcifront_xenbus_remove,
1163         .otherend_changed       = pcifront_backend_changed,
1164 };
1165
1166 static int __init pcifront_init(void)
1167 {
1168         if (!xen_pv_domain() || xen_initial_domain())
1169                 return -ENODEV;
1170
1171         if (!xen_has_pv_devices())
1172                 return -ENODEV;
1173
1174         pci_frontend_registrar(1 /* enable */);
1175
1176         return xenbus_register_frontend(&xenpci_driver);
1177 }
1178
1179 static void __exit pcifront_cleanup(void)
1180 {
1181         xenbus_unregister_driver(&xenpci_driver);
1182         pci_frontend_registrar(0 /* disable */);
1183 }
1184 module_init(pcifront_init);
1185 module_exit(pcifront_cleanup);
1186
1187 MODULE_DESCRIPTION("Xen PCI passthrough frontend.");
1188 MODULE_LICENSE("GPL");
1189 MODULE_ALIAS("xen:pci");