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                         pr_info("enable msix get value %x\n", op.value);
 295                         err = op.value;
 296                 }
 297         } else {
 298                 pci_err(dev, "enable msix get err %x\n", err);
 299         }
 300         return err;
 301 }
 302
 303 static void pci_frontend_disable_msix(struct pci_dev *dev)
 304 {
 305         int err;
 306         struct xen_pci_op op = {
 307                 .cmd    = XEN_PCI_OP_disable_msix,
 308                 .domain = pci_domain_nr(dev->bus),
 309                 .bus = dev->bus->number,
 310                 .devfn = dev->devfn,
 311         };
 312         struct pcifront_sd *sd = dev->bus->sysdata;
 313         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 314
 315         err = do_pci_op(pdev, &op);
 316
 317         /* What should do for error ? */
 318         if (err)
 319                 pci_err(dev, "pci_disable_msix get err %x\n", err);
 320 }
 321
 322 static int pci_frontend_enable_msi(struct pci_dev *dev, int vector[])
 323 {
 324         int err;
 325         struct xen_pci_op op = {
 326                 .cmd    = XEN_PCI_OP_enable_msi,
 327                 .domain = pci_domain_nr(dev->bus),
 328                 .bus = dev->bus->number,
 329                 .devfn = dev->devfn,
 330         };
 331         struct pcifront_sd *sd = dev->bus->sysdata;
 332         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 333
 334         err = do_pci_op(pdev, &op);
 335         if (likely(!err)) {
 336                 vector[0] = op.value;
 337                 if (op.value <= 0) {
 338                         pci_warn(dev, "MSI entry is invalid: %d!\n",
 339                                 op.value);
 340                         err = -EINVAL;
 341                         vector[0] = -1;
 342                 }
 343         } else {
 344                 pci_err(dev, "pci frontend enable msi failed for dev "
 345                                     "%x:%x\n", op.bus, op.devfn);
 346                 err = -EINVAL;
 347         }
 348         return err;
 349 }
 350
 351 static void pci_frontend_disable_msi(struct pci_dev *dev)
 352 {
 353         int err;
 354         struct xen_pci_op op = {
 355                 .cmd    = XEN_PCI_OP_disable_msi,
 356                 .domain = pci_domain_nr(dev->bus),
 357                 .bus = dev->bus->number,
 358                 .devfn = dev->devfn,
 359         };
 360         struct pcifront_sd *sd = dev->bus->sysdata;
 361         struct pcifront_device *pdev = pcifront_get_pdev(sd);
 362
 363         err = do_pci_op(pdev, &op);
 364         if (err == XEN_PCI_ERR_dev_not_found) {
 365                 /* XXX No response from backend, what shall we do? */
 366                 pr_info("get no response from backend for disable MSI\n");
 367                 return;
 368         }
 369         if (err)
 370                 /* how can pciback notify us fail? */
 371                 pr_info("get fake response from backend\n");
 372 }
 373
 374 static struct xen_pci_frontend_ops pci_frontend_ops = {
 375         .enable_msi = pci_frontend_enable_msi,
 376         .disable_msi = pci_frontend_disable_msi,
 377         .enable_msix = pci_frontend_enable_msix,
 378         .disable_msix = pci_frontend_disable_msix,
 379 };
 380
 381 static void pci_frontend_registrar(int enable)
 382 {
 383         if (enable)
 384                 xen_pci_frontend = &pci_frontend_ops;
 385         else
 386                 xen_pci_frontend = NULL;
 387 };
 388 #else
 389 static inline void pci_frontend_registrar(int enable) { };
 390 #endif /* CONFIG_PCI_MSI */
 391
 392 /* Claim resources for the PCI frontend as-is, backend won't allow changes */
 393 static int pcifront_claim_resource(struct pci_dev *dev, void *data)
 394 {
 395         struct pcifront_device *pdev = data;
 396         int i;
 397         struct resource *r;
 398
 399         for (i = 0; i < PCI_NUM_RESOURCES; i++) {
 400                 r = &dev->resource[i];
 401
 402                 if (!r->parent && r->start && r->flags) {
 403                         dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n",
 404                                 pci_name(dev), i);
 405                         if (pci_claim_resource(dev, i)) {
 406                                 dev_err(&pdev->xdev->dev, "Could not claim resource %s/%d! "
 407                                         "Device offline. Try using e820_host=1 in the guest config.\n",
 408                                         pci_name(dev), i);
 409                         }
 410                 }
 411         }
 412
 413         return 0;
 414 }
 415
 416 static int pcifront_scan_bus(struct pcifront_device *pdev,
 417                                 unsigned int domain, unsigned int bus,
 418                                 struct pci_bus *b)
 419 {
 420         struct pci_dev *d;
 421         unsigned int devfn;
 422
 423         /* Scan the bus for functions and add.
 424          * We omit handling of PCI bridge attachment because pciback prevents
 425          * bridges from being exported.
 426          */
 427         for (devfn = 0; devfn < 0x100; devfn++) {
 428                 d = pci_get_slot(b, devfn);
 429                 if (d) {
 430                         /* Device is already known. */
 431                         pci_dev_put(d);
 432                         continue;
 433                 }
 434
 435                 d = pci_scan_single_device(b, devfn);
 436                 if (d)
 437                         dev_info(&pdev->xdev->dev, "New device on "
 438                                  "%04x:%02x:%02x.%d found.\n", domain, bus,
 439                                  PCI_SLOT(devfn), PCI_FUNC(devfn));
 440         }
 441
 442         return 0;
 443 }
 444
 445 static int pcifront_scan_root(struct pcifront_device *pdev,
 446                                  unsigned int domain, unsigned int bus)
 447 {
 448         struct pci_bus *b;
 449         LIST_HEAD(resources);
 450         struct pcifront_sd *sd = NULL;
 451         struct pci_bus_entry *bus_entry = NULL;
 452         int err = 0;
 453         static struct resource busn_res = {
 454                 .start = 0,
 455                 .end = 255,
 456                 .flags = IORESOURCE_BUS,
 457         };
 458
 459 #ifndef CONFIG_PCI_DOMAINS
 460         if (domain != 0) {
 461                 dev_err(&pdev->xdev->dev,
 462                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 463                 dev_err(&pdev->xdev->dev,
 464                         "Please compile with CONFIG_PCI_DOMAINS\n");
 465                 err = -EINVAL;
 466                 goto err_out;
 467         }
 468 #endif
 469
 470         dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n",
 471                  domain, bus);
 472
 473         bus_entry = kzalloc(sizeof(*bus_entry), GFP_KERNEL);
 474         sd = kzalloc(sizeof(*sd), GFP_KERNEL);
 475         if (!bus_entry || !sd) {
 476                 err = -ENOMEM;
 477                 goto err_out;
 478         }
 479         pci_add_resource(&resources, &ioport_resource);
 480         pci_add_resource(&resources, &iomem_resource);
 481         pci_add_resource(&resources, &busn_res);
 482         pcifront_init_sd(sd, domain, bus, pdev);
 483
 484         pci_lock_rescan_remove();
 485
 486         b = pci_scan_root_bus(&pdev->xdev->dev, bus,
 487                                   &pcifront_bus_ops, sd, &resources);
 488         if (!b) {
 489                 dev_err(&pdev->xdev->dev,
 490                         "Error creating PCI Frontend Bus!\n");
 491                 err = -ENOMEM;
 492                 pci_unlock_rescan_remove();
 493                 pci_free_resource_list(&resources);
 494                 goto err_out;
 495         }
 496
 497         bus_entry->bus = b;
 498
 499         list_add(&bus_entry->list, &pdev->root_buses);
 500
 501         /* pci_scan_root_bus skips devices which do not have a
 502         * devfn==0. The pcifront_scan_bus enumerates all devfn. */
 503         err = pcifront_scan_bus(pdev, domain, bus, b);
 504
 505         /* Claim resources before going "live" with our devices */
 506         pci_walk_bus(b, pcifront_claim_resource, pdev);
 507
 508         /* Create SysFS and notify udev of the devices. Aka: "going live" */
 509         pci_bus_add_devices(b);
 510
 511         pci_unlock_rescan_remove();
 512         return err;
 513
 514 err_out:
 515         kfree(bus_entry);
 516         kfree(sd);
 517
 518         return err;
 519 }
 520
 521 static int pcifront_rescan_root(struct pcifront_device *pdev,
 522                                    unsigned int domain, unsigned int bus)
 523 {
 524         int err;
 525         struct pci_bus *b;
 526
 527 #ifndef CONFIG_PCI_DOMAINS
 528         if (domain != 0) {
 529                 dev_err(&pdev->xdev->dev,
 530                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 531                 dev_err(&pdev->xdev->dev,
 532                         "Please compile with CONFIG_PCI_DOMAINS\n");
 533                 return -EINVAL;
 534         }
 535 #endif
 536
 537         dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
 538                  domain, bus);
 539
 540         b = pci_find_bus(domain, bus);
 541         if (!b)
 542                 /* If the bus is unknown, create it. */
 543                 return pcifront_scan_root(pdev, domain, bus);
 544
 545         err = pcifront_scan_bus(pdev, domain, bus, b);
 546
 547         /* Claim resources before going "live" with our devices */
 548         pci_walk_bus(b, pcifront_claim_resource, pdev);
 549
 550         /* Create SysFS and notify udev of the devices. Aka: "going live" */
 551         pci_bus_add_devices(b);
 552
 553         return err;
 554 }
 555
 556 static void free_root_bus_devs(struct pci_bus *bus)
 557 {
 558         struct pci_dev *dev;
 559
 560         while (!list_empty(&bus->devices)) {
 561                 dev = container_of(bus->devices.next, struct pci_dev,
 562                                    bus_list);
 563                 pci_dbg(dev, "removing device\n");
 564                 pci_stop_and_remove_bus_device(dev);
 565         }
 566 }
 567
 568 static void pcifront_free_roots(struct pcifront_device *pdev)
 569 {
 570         struct pci_bus_entry *bus_entry, *t;
 571
 572         dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n");
 573
 574         pci_lock_rescan_remove();
 575         list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) {
 576                 list_del(&bus_entry->list);
 577
 578                 free_root_bus_devs(bus_entry->bus);
 579
 580                 kfree(bus_entry->bus->sysdata);
 581
 582                 device_unregister(bus_entry->bus->bridge);
 583                 pci_remove_bus(bus_entry->bus);
 584
 585                 kfree(bus_entry);
 586         }
 587         pci_unlock_rescan_remove();
 588 }
 589
 590 static pci_ers_result_t pcifront_common_process(int cmd,
 591                                                 struct pcifront_device *pdev,
 592                                                 pci_channel_state_t state)
 593 {
 594         pci_ers_result_t result;
 595         struct pci_driver *pdrv;
 596         int bus = pdev->sh_info->aer_op.bus;
 597         int devfn = pdev->sh_info->aer_op.devfn;
 598         int domain = pdev->sh_info->aer_op.domain;
 599         struct pci_dev *pcidev;
 600         int flag = 0;
 601
 602         dev_dbg(&pdev->xdev->dev,
 603                 "pcifront AER process: cmd %x (bus:%x, devfn%x)",
 604                 cmd, bus, devfn);
 605         result = PCI_ERS_RESULT_NONE;
 606
 607         pcidev = pci_get_domain_bus_and_slot(domain, bus, devfn);
 608         if (!pcidev || !pcidev->driver) {
 609                 dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
 610                 pci_dev_put(pcidev);
 611                 return result;
 612         }
 613         pdrv = pcidev->driver;
 614
 615         if (pdrv) {
 616                 if (pdrv->err_handler && pdrv->err_handler->error_detected) {
 617                         pci_dbg(pcidev, "trying to call AER service\n");
 618                         if (pcidev) {
 619                                 flag = 1;
 620                                 switch (cmd) {
 621                                 case XEN_PCI_OP_aer_detected:
 622                                         result = pdrv->err_handler->
 623                                                  error_detected(pcidev, state);
 624                                         break;
 625                                 case XEN_PCI_OP_aer_mmio:
 626                                         result = pdrv->err_handler->
 627                                                  mmio_enabled(pcidev);
 628                                         break;
 629                                 case XEN_PCI_OP_aer_slotreset:
 630                                         result = pdrv->err_handler->
 631                                                  slot_reset(pcidev);
 632                                         break;
 633                                 case XEN_PCI_OP_aer_resume:
 634                                         pdrv->err_handler->resume(pcidev);
 635                                         break;
 636                                 default:
 637                                         dev_err(&pdev->xdev->dev,
 638                                                 "bad request in aer recovery "
 639                                                 "operation!\n");
 640
 641                                 }
 642                         }
 643                 }
 644         }
 645         if (!flag)
 646                 result = PCI_ERS_RESULT_NONE;
 647
 648         return result;
 649 }
 650
 651
 652 static void pcifront_do_aer(struct work_struct *data)
 653 {
 654         struct pcifront_device *pdev =
 655                 container_of(data, struct pcifront_device, op_work);
 656         int cmd = pdev->sh_info->aer_op.cmd;
 657         pci_channel_state_t state =
 658                 (pci_channel_state_t)pdev->sh_info->aer_op.err;
 659
 660         /*If a pci_conf op is in progress,
 661                 we have to wait until it is done before service aer op*/
 662         dev_dbg(&pdev->xdev->dev,
 663                 "pcifront service aer bus %x devfn %x\n",
 664                 pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn);
 665
 666         pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state);
 667
 668         /* Post the operation to the guest. */
 669         wmb();
 670         clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags);
 671         notify_remote_via_evtchn(pdev->evtchn);
 672
 673         /*in case of we lost an aer request in four lines time_window*/
 674         smp_mb__before_atomic();
 675         clear_bit(_PDEVB_op_active, &pdev->flags);
 676         smp_mb__after_atomic();
 677
 678         schedule_pcifront_aer_op(pdev);
 679
 680 }
 681
 682 static irqreturn_t pcifront_handler_aer(int irq, void *dev)
 683 {
 684         struct pcifront_device *pdev = dev;
 685         schedule_pcifront_aer_op(pdev);
 686         return IRQ_HANDLED;
 687 }
 688 static int pcifront_connect_and_init_dma(struct pcifront_device *pdev)
 689 {
 690         int err = 0;
 691
 692         spin_lock(&pcifront_dev_lock);
 693
 694         if (!pcifront_dev) {
 695                 dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
 696                 pcifront_dev = pdev;
 697         } else
 698                 err = -EEXIST;
 699
 700         spin_unlock(&pcifront_dev_lock);
 701
 702         if (!err && !swiotlb_nr_tbl()) {
 703                 err = pci_xen_swiotlb_init_late();
 704                 if (err)
 705                         dev_err(&pdev->xdev->dev, "Could not setup SWIOTLB!\n");
 706         }
 707         return err;
 708 }
 709
 710 static void pcifront_disconnect(struct pcifront_device *pdev)
 711 {
 712         spin_lock(&pcifront_dev_lock);
 713
 714         if (pdev == pcifront_dev) {
 715                 dev_info(&pdev->xdev->dev,
 716                          "Disconnecting PCI Frontend Buses\n");
 717                 pcifront_dev = NULL;
 718         }
 719
 720         spin_unlock(&pcifront_dev_lock);
 721 }
 722 static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev)
 723 {
 724         struct pcifront_device *pdev;
 725
 726         pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL);
 727         if (pdev == NULL)
 728                 goto out;
 729
 730         pdev->sh_info =
 731             (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL);
 732         if (pdev->sh_info == NULL) {
 733                 kfree(pdev);
 734                 pdev = NULL;
 735                 goto out;
 736         }
 737         pdev->sh_info->flags = 0;
 738
 739         /*Flag for registering PV AER handler*/
 740         set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags);
 741
 742         dev_set_drvdata(&xdev->dev, pdev);
 743         pdev->xdev = xdev;
 744
 745         INIT_LIST_HEAD(&pdev->root_buses);
 746
 747         spin_lock_init(&pdev->sh_info_lock);
 748
 749         pdev->evtchn = INVALID_EVTCHN;
 750         pdev->gnt_ref = INVALID_GRANT_REF;
 751         pdev->irq = -1;
 752
 753         INIT_WORK(&pdev->op_work, pcifront_do_aer);
 754
 755         dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n",
 756                 pdev, pdev->sh_info);
 757 out:
 758         return pdev;
 759 }
 760
 761 static void free_pdev(struct pcifront_device *pdev)
 762 {
 763         dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
 764
 765         pcifront_free_roots(pdev);
 766
 767         cancel_work_sync(&pdev->op_work);
 768
 769         if (pdev->irq >= 0)
 770                 unbind_from_irqhandler(pdev->irq, pdev);
 771
 772         if (pdev->evtchn != INVALID_EVTCHN)
 773                 xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
 774
 775         if (pdev->gnt_ref != INVALID_GRANT_REF)
 776                 gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
 777                                           (unsigned long)pdev->sh_info);
 778         else
 779                 free_page((unsigned long)pdev->sh_info);
 780
 781         dev_set_drvdata(&pdev->xdev->dev, NULL);
 782
 783         kfree(pdev);
 784 }
 785
 786 static int pcifront_publish_info(struct pcifront_device *pdev)
 787 {
 788         int err = 0;
 789         struct xenbus_transaction trans;
 790         grant_ref_t gref;
 791
 792         err = xenbus_grant_ring(pdev->xdev, pdev->sh_info, 1, &gref);
 793         if (err < 0)
 794                 goto out;
 795
 796         pdev->gnt_ref = gref;
 797
 798         err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
 799         if (err)
 800                 goto out;
 801
 802         err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer,
 803                 0, "pcifront", pdev);
 804
 805         if (err < 0)
 806                 return err;
 807
 808         pdev->irq = err;
 809
 810 do_publish:
 811         err = xenbus_transaction_start(&trans);
 812         if (err) {
 813                 xenbus_dev_fatal(pdev->xdev, err,
 814                                  "Error writing configuration for backend "
 815                                  "(start transaction)");
 816                 goto out;
 817         }
 818
 819         err = xenbus_printf(trans, pdev->xdev->nodename,
 820                             "pci-op-ref", "%u", pdev->gnt_ref);
 821         if (!err)
 822                 err = xenbus_printf(trans, pdev->xdev->nodename,
 823                                     "event-channel", "%u", pdev->evtchn);
 824         if (!err)
 825                 err = xenbus_printf(trans, pdev->xdev->nodename,
 826                                     "magic", XEN_PCI_MAGIC);
 827
 828         if (err) {
 829                 xenbus_transaction_end(trans, 1);
 830                 xenbus_dev_fatal(pdev->xdev, err,
 831                                  "Error writing configuration for backend");
 832                 goto out;
 833         } else {
 834                 err = xenbus_transaction_end(trans, 0);
 835                 if (err == -EAGAIN)
 836                         goto do_publish;
 837                 else if (err) {
 838                         xenbus_dev_fatal(pdev->xdev, err,
 839                                          "Error completing transaction "
 840                                          "for backend");
 841                         goto out;
 842                 }
 843         }
 844
 845         xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
 846
 847         dev_dbg(&pdev->xdev->dev, "publishing successful!\n");
 848
 849 out:
 850         return err;
 851 }
 852
 853 static int pcifront_try_connect(struct pcifront_device *pdev)
 854 {
 855         int err = -EFAULT;
 856         int i, num_roots, len;
 857         char str[64];
 858         unsigned int domain, bus;
 859
 860
 861         /* Only connect once */
 862         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 863             XenbusStateInitialised)
 864                 goto out;
 865
 866         err = pcifront_connect_and_init_dma(pdev);
 867         if (err && err != -EEXIST) {
 868                 xenbus_dev_fatal(pdev->xdev, err,
 869                                  "Error setting up PCI Frontend");
 870                 goto out;
 871         }
 872
 873         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 874                            "root_num", "%d", &num_roots);
 875         if (err == -ENOENT) {
 876                 xenbus_dev_error(pdev->xdev, err,
 877                                  "No PCI Roots found, trying 0000:00");
 878                 err = pcifront_scan_root(pdev, 0, 0);
 879                 if (err) {
 880                         xenbus_dev_fatal(pdev->xdev, err,
 881                                          "Error scanning PCI root 0000:00");
 882                         goto out;
 883                 }
 884                 num_roots = 0;
 885         } else if (err != 1) {
 886                 if (err == 0)
 887                         err = -EINVAL;
 888                 xenbus_dev_fatal(pdev->xdev, err,
 889                                  "Error reading number of PCI roots");
 890                 goto out;
 891         }
 892
 893         for (i = 0; i < num_roots; i++) {
 894                 len = snprintf(str, sizeof(str), "root-%d", i);
 895                 if (unlikely(len >= (sizeof(str) - 1))) {
 896                         err = -ENOMEM;
 897                         goto out;
 898                 }
 899
 900                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 901                                    "%x:%x", &domain, &bus);
 902                 if (err != 2) {
 903                         if (err >= 0)
 904                                 err = -EINVAL;
 905                         xenbus_dev_fatal(pdev->xdev, err,
 906                                          "Error reading PCI root %d", i);
 907                         goto out;
 908                 }
 909
 910                 err = pcifront_scan_root(pdev, domain, bus);
 911                 if (err) {
 912                         xenbus_dev_fatal(pdev->xdev, err,
 913                                          "Error scanning PCI root %04x:%02x",
 914                                          domain, bus);
 915                         goto out;
 916                 }
 917         }
 918
 919         err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 920
 921 out:
 922         return err;
 923 }
 924
 925 static int pcifront_try_disconnect(struct pcifront_device *pdev)
 926 {
 927         int err = 0;
 928         enum xenbus_state prev_state;
 929
 930
 931         prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
 932
 933         if (prev_state >= XenbusStateClosing)
 934                 goto out;
 935
 936         if (prev_state == XenbusStateConnected) {
 937                 pcifront_free_roots(pdev);
 938                 pcifront_disconnect(pdev);
 939         }
 940
 941         err = xenbus_switch_state(pdev->xdev, XenbusStateClosed);
 942
 943 out:
 944
 945         return err;
 946 }
 947
 948 static int pcifront_attach_devices(struct pcifront_device *pdev)
 949 {
 950         int err = -EFAULT;
 951         int i, num_roots, len;
 952         unsigned int domain, bus;
 953         char str[64];
 954
 955         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 956             XenbusStateReconfiguring)
 957                 goto out;
 958
 959         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 960                            "root_num", "%d", &num_roots);
 961         if (err == -ENOENT) {
 962                 xenbus_dev_error(pdev->xdev, err,
 963                                  "No PCI Roots found, trying 0000:00");
 964                 err = pcifront_rescan_root(pdev, 0, 0);
 965                 if (err) {
 966                         xenbus_dev_fatal(pdev->xdev, err,
 967                                          "Error scanning PCI root 0000:00");
 968                         goto out;
 969                 }
 970                 num_roots = 0;
 971         } else if (err != 1) {
 972                 if (err == 0)
 973                         err = -EINVAL;
 974                 xenbus_dev_fatal(pdev->xdev, err,
 975                                  "Error reading number of PCI roots");
 976                 goto out;
 977         }
 978
 979         for (i = 0; i < num_roots; i++) {
 980                 len = snprintf(str, sizeof(str), "root-%d", i);
 981                 if (unlikely(len >= (sizeof(str) - 1))) {
 982                         err = -ENOMEM;
 983                         goto out;
 984                 }
 985
 986                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 987                                    "%x:%x", &domain, &bus);
 988                 if (err != 2) {
 989                         if (err >= 0)
 990                                 err = -EINVAL;
 991                         xenbus_dev_fatal(pdev->xdev, err,
 992                                          "Error reading PCI root %d", i);
 993                         goto out;
 994                 }
 995
 996                 err = pcifront_rescan_root(pdev, domain, bus);
 997                 if (err) {
 998                         xenbus_dev_fatal(pdev->xdev, err,
 999                                          "Error scanning PCI root %04x:%02x",
1000                                          domain, bus);
1001                         goto out;
1002                 }
1003         }
1004
1005         xenbus_switch_state(pdev->xdev, XenbusStateConnected);
1006
1007 out:
1008         return err;
1009 }
1010
1011 static int pcifront_detach_devices(struct pcifront_device *pdev)
1012 {
1013         int err = 0;
1014         int i, num_devs;
1015         unsigned int domain, bus, slot, func;
1016         struct pci_dev *pci_dev;
1017         char str[64];
1018
1019         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
1020             XenbusStateConnected)
1021                 goto out;
1022
1023         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d",
1024                            &num_devs);
1025         if (err != 1) {
1026                 if (err >= 0)
1027                         err = -EINVAL;
1028                 xenbus_dev_fatal(pdev->xdev, err,
1029                                  "Error reading number of PCI devices");
1030                 goto out;
1031         }
1032
1033         /* Find devices being detached and remove them. */
1034         for (i = 0; i < num_devs; i++) {
1035                 int l, state;
1036                 l = snprintf(str, sizeof(str), "state-%d", i);
1037                 if (unlikely(l >= (sizeof(str) - 1))) {
1038                         err = -ENOMEM;
1039                         goto out;
1040                 }
1041                 state = xenbus_read_unsigned(pdev->xdev->otherend, str,
1042                                              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 __ref 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                 /* fall through - Missed the backend's CLOSING state. */
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");