linux/drivers/pci/xen-pcifront.c
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   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
  30struct 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
  38struct 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
  55struct pcifront_sd {
  56        struct pci_sysdata sd;
  57        struct pcifront_device *pdev;
  58};
  59
  60static inline struct pcifront_device *
  61pcifront_get_pdev(struct pcifront_sd *sd)
  62{
  63        return sd->pdev;
  64}
  65
  66static inline void pcifront_init_sd(struct pcifront_sd *sd,
  67                                    unsigned int domain, unsigned int bus,
  68                                    struct pcifront_device *pdev)
  69{
  70        /* Because we do not expose that information via XenBus. */
  71        sd->sd.node = first_online_node;
  72        sd->sd.domain = domain;
  73        sd->pdev = pdev;
  74}
  75
  76static DEFINE_SPINLOCK(pcifront_dev_lock);
  77static struct pcifront_device *pcifront_dev;
  78
  79static int verbose_request;
  80module_param(verbose_request, int, 0644);
  81
  82static int errno_to_pcibios_err(int errno)
  83{
  84        switch (errno) {
  85        case XEN_PCI_ERR_success:
  86                return PCIBIOS_SUCCESSFUL;
  87
  88        case XEN_PCI_ERR_dev_not_found:
  89                return PCIBIOS_DEVICE_NOT_FOUND;
  90
  91        case XEN_PCI_ERR_invalid_offset:
  92        case XEN_PCI_ERR_op_failed:
  93                return PCIBIOS_BAD_REGISTER_NUMBER;
  94
  95        case XEN_PCI_ERR_not_implemented:
  96                return PCIBIOS_FUNC_NOT_SUPPORTED;
  97
  98        case XEN_PCI_ERR_access_denied:
  99                return PCIBIOS_SET_FAILED;
 100        }
 101        return errno;
 102}
 103
 104static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev)
 105{
 106        if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
 107                && !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) {
 108                dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n");
 109                schedule_work(&pdev->op_work);
 110        }
 111}
 112
 113static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 114{
 115        int err = 0;
 116        struct xen_pci_op *active_op = &pdev->sh_info->op;
 117        unsigned long irq_flags;
 118        evtchn_port_t port = pdev->evtchn;
 119        unsigned irq = pdev->irq;
 120        s64 ns, ns_timeout;
 121
 122        spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
 123
 124        memcpy(active_op, op, sizeof(struct xen_pci_op));
 125
 126        /* Go */
 127        wmb();
 128        set_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
 129        notify_remote_via_evtchn(port);
 130
 131        /*
 132         * We set a poll timeout of 3 seconds but give up on return after
 133         * 2 seconds. It is better to time out too late rather than too early
 134         * (in the latter case we end up continually re-executing poll() with a
 135         * timeout in the past). 1s difference gives plenty of slack for error.
 136         */
 137        ns_timeout = ktime_get_ns() + 2 * (s64)NSEC_PER_SEC;
 138
 139        xen_clear_irq_pending(irq);
 140
 141        while (test_bit(_XEN_PCIF_active,
 142                        (unsigned long *)&pdev->sh_info->flags)) {
 143                xen_poll_irq_timeout(irq, jiffies + 3*HZ);
 144                xen_clear_irq_pending(irq);
 145                ns = ktime_get_ns();
 146                if (ns > ns_timeout) {
 147                        dev_err(&pdev->xdev->dev,
 148                                "pciback not responding!!!\n");
 149                        clear_bit(_XEN_PCIF_active,
 150                                  (unsigned long *)&pdev->sh_info->flags);
 151                        err = XEN_PCI_ERR_dev_not_found;
 152                        goto out;
 153                }
 154        }
 155
 156        /*
 157        * We might lose backend service request since we
 158        * reuse same evtchn with pci_conf backend response. So re-schedule
 159        * aer pcifront service.
 160        */
 161        if (test_bit(_XEN_PCIB_active,
 162                        (unsigned long *)&pdev->sh_info->flags)) {
 163                dev_err(&pdev->xdev->dev,
 164                        "schedule aer pcifront service\n");
 165                schedule_pcifront_aer_op(pdev);
 166        }
 167
 168        memcpy(op, active_op, sizeof(struct xen_pci_op));
 169
 170        err = op->err;
 171out:
 172        spin_unlock_irqrestore(&pdev->sh_info_lock, irq_flags);
 173        return err;
 174}
 175
 176/* Access to this function is spinlocked in drivers/pci/access.c */
 177static int pcifront_bus_read(struct pci_bus *bus, unsigned int devfn,
 178                             int where, int size, u32 *val)
 179{
 180        int err = 0;
 181        struct xen_pci_op op = {
 182                .cmd    = XEN_PCI_OP_conf_read,
 183                .domain = pci_domain_nr(bus),
 184                .bus    = bus->number,
 185                .devfn  = devfn,
 186                .offset = where,
 187                .size   = size,
 188        };
 189        struct pcifront_sd *sd = bus->sysdata;
 190        struct pcifront_device *pdev = pcifront_get_pdev(sd);
 191
 192        if (verbose_request)
 193                dev_info(&pdev->xdev->dev,
 194                         "read dev=%04x:%02x:%02x.%d - offset %x size %d\n",
 195                         pci_domain_nr(bus), bus->number, PCI_SLOT(devfn),
 196                         PCI_FUNC(devfn), where, size);
 197
 198        err = do_pci_op(pdev, &op);
 199
 200        if (likely(!err)) {
 201                if (verbose_request)
 202                        dev_info(&pdev->xdev->dev, "read got back value %x\n",
 203                                 op.value);
 204
 205                *val = op.value;
 206        } else if (err == -ENODEV) {
 207                /* No device here, pretend that it just returned 0 */
 208                err = 0;
 209                *val = 0;
 210        }
 211
 212        return errno_to_pcibios_err(err);
 213}
 214
 215/* Access to this function is spinlocked in drivers/pci/access.c */
 216static int pcifront_bus_write(struct pci_bus *bus, unsigned int devfn,
 217                              int where, int size, u32 val)
 218{
 219        struct xen_pci_op op = {
 220                .cmd    = XEN_PCI_OP_conf_write,
 221                .domain = pci_domain_nr(bus),
 222                .bus    = bus->number,
 223                .devfn  = devfn,
 224                .offset = where,
 225                .size   = size,
 226                .value  = val,
 227        };
 228        struct pcifront_sd *sd = bus->sysdata;
 229        struct pcifront_device *pdev = pcifront_get_pdev(sd);
 230
 231        if (verbose_request)
 232                dev_info(&pdev->xdev->dev,
 233                         "write dev=%04x:%02x:%02x.%d - "
 234                         "offset %x size %d val %x\n",
 235                         pci_domain_nr(bus), bus->number,
 236                         PCI_SLOT(devfn), PCI_FUNC(devfn), where, size, val);
 237
 238        return errno_to_pcibios_err(do_pci_op(pdev, &op));
 239}
 240
 241static struct pci_ops pcifront_bus_ops = {
 242        .read = pcifront_bus_read,
 243        .write = pcifront_bus_write,
 244};
 245
 246#ifdef CONFIG_PCI_MSI
 247static int pci_frontend_enable_msix(struct pci_dev *dev,
 248                                    int vector[], int nvec)
 249{
 250        int err;
 251        int i;
 252        struct xen_pci_op op = {
 253                .cmd    = XEN_PCI_OP_enable_msix,
 254                .domain = pci_domain_nr(dev->bus),
 255                .bus = dev->bus->number,
 256                .devfn = dev->devfn,
 257                .value = nvec,
 258        };
 259        struct pcifront_sd *sd = dev->bus->sysdata;
 260        struct pcifront_device *pdev = pcifront_get_pdev(sd);
 261        struct msi_desc *entry;
 262
 263        if (nvec > SH_INFO_MAX_VEC) {
 264                dev_err(&dev->dev, "too much vector for pci frontend: %x."
 265                                   " Increase SH_INFO_MAX_VEC.\n", nvec);
 266                return -EINVAL;
 267        }
 268
 269        i = 0;
 270        for_each_pci_msi_entry(entry, dev) {
 271                op.msix_entries[i].entry = entry->msi_attrib.entry_nr;
 272                /* Vector is useless at this point. */
 273                op.msix_entries[i].vector = -1;
 274                i++;
 275        }
 276
 277        err = do_pci_op(pdev, &op);
 278
 279        if (likely(!err)) {
 280                if (likely(!op.value)) {
 281                        /* we get the result */
 282                        for (i = 0; i < nvec; i++) {
 283                                if (op.msix_entries[i].vector <= 0) {
 284                                        dev_warn(&dev->dev, "MSI-X entry %d is invalid: %d!\n",
 285                                                i, op.msix_entries[i].vector);
 286                                        err = -EINVAL;
 287                                        vector[i] = -1;
 288                                        continue;
 289                                }
 290                                vector[i] = op.msix_entries[i].vector;
 291                        }
 292                } else {
 293                        printk(KERN_DEBUG "enable msix get value %x\n",
 294                                op.value);
 295                        err = op.value;
 296                }
 297        } else {
 298                dev_err(&dev->dev, "enable msix get err %x\n", err);
 299        }
 300        return err;
 301}
 302
 303static 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                dev_err(&dev->dev, "pci_disable_msix get err %x\n", err);
 320}
 321
 322static 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                        dev_warn(&dev->dev, "MSI entry is invalid: %d!\n",
 339                                op.value);
 340                        err = -EINVAL;
 341                        vector[0] = -1;
 342                }
 343        } else {
 344                dev_err(&dev->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
 351static 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                printk(KERN_DEBUG "get no response from backend for disable MSI\n");
 367                return;
 368        }
 369        if (err)
 370                /* how can pciback notify us fail? */
 371                printk(KERN_DEBUG "get fake response frombackend\n");
 372}
 373
 374static 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
 381static 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
 389static 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 */
 393static 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
 416static 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
 445static 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
 514err_out:
 515        kfree(bus_entry);
 516        kfree(sd);
 517
 518        return err;
 519}
 520
 521static 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
 556static 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                dev_dbg(&dev->dev, "removing device\n");
 564                pci_stop_and_remove_bus_device(dev);
 565        }
 566}
 567
 568static 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
 590static 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        struct pci_dev *pcidev;
 599        int flag = 0;
 600
 601        dev_dbg(&pdev->xdev->dev,
 602                "pcifront AER process: cmd %x (bus:%x, devfn%x)",
 603                cmd, bus, devfn);
 604        result = PCI_ERS_RESULT_NONE;
 605
 606        pcidev = pci_get_bus_and_slot(bus, devfn);
 607        if (!pcidev || !pcidev->driver) {
 608                dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
 609                pci_dev_put(pcidev);
 610                return result;
 611        }
 612        pdrv = pcidev->driver;
 613
 614        if (pdrv) {
 615                if (pdrv->err_handler && pdrv->err_handler->error_detected) {
 616                        dev_dbg(&pcidev->dev,
 617                                "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
 652static 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
 682static 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}
 688static 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
 710static 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}
 722static 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);
 757out:
 758        return pdev;
 759}
 760
 761static 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
 786static 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
 810do_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
 849out:
 850        return err;
 851}
 852
 853static 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
 921out:
 922        return err;
 923}
 924
 925static 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
 943out:
 944
 945        return err;
 946}
 947
 948static 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
1007out:
1008        return err;
1009}
1010
1011static 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
1083out:
1084        return err;
1085}
1086
1087static 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                /* 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
1122static 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
1139out:
1140        return err;
1141}
1142
1143static 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
1152static const struct xenbus_device_id xenpci_ids[] = {
1153        {"pci"},
1154        {""},
1155};
1156
1157static 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
1165static 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
1178static void __exit pcifront_cleanup(void)
1179{
1180        xenbus_unregister_driver(&xenpci_driver);
1181        pci_frontend_registrar(0 /* disable */);
1182}
1183module_init(pcifront_init);
1184module_exit(pcifront_cleanup);
1185
1186MODULE_DESCRIPTION("Xen PCI passthrough frontend.");
1187MODULE_LICENSE("GPL");
1188MODULE_ALIAS("xen:pci");
1189