linux/drivers/pci/xen-pcifront.c
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   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 <linux/swiotlb.h>
  26#include <xen/platform_pci.h>
  27
  28#include <asm/xen/swiotlb-xen.h>
  29
  30#define INVALID_EVTCHN    (-1)
  31
  32struct pci_bus_entry {
  33        struct list_head list;
  34        struct pci_bus *bus;
  35};
  36
  37#define _PDEVB_op_active                (0)
  38#define PDEVB_op_active                 (1 << (_PDEVB_op_active))
  39
  40struct pcifront_device {
  41        struct xenbus_device *xdev;
  42        struct list_head root_buses;
  43
  44        int evtchn;
  45        grant_ref_t gnt_ref;
  46
  47        int irq;
  48
  49        /* Lock this when doing any operations in sh_info */
  50        spinlock_t sh_info_lock;
  51        struct xen_pci_sharedinfo *sh_info;
  52        struct work_struct op_work;
  53        unsigned long flags;
  54
  55};
  56
  57struct pcifront_sd {
  58        struct pci_sysdata sd;
  59        struct pcifront_device *pdev;
  60};
  61
  62static inline struct pcifront_device *
  63pcifront_get_pdev(struct pcifront_sd *sd)
  64{
  65        return sd->pdev;
  66}
  67
  68static inline void pcifront_init_sd(struct pcifront_sd *sd,
  69                                    unsigned int domain, unsigned int bus,
  70                                    struct pcifront_device *pdev)
  71{
  72        /* Because we do not expose that information via XenBus. */
  73        sd->sd.node = first_online_node;
  74        sd->sd.domain = domain;
  75        sd->pdev = pdev;
  76}
  77
  78static DEFINE_SPINLOCK(pcifront_dev_lock);
  79static struct pcifront_device *pcifront_dev;
  80
  81static int errno_to_pcibios_err(int errno)
  82{
  83        switch (errno) {
  84        case XEN_PCI_ERR_success:
  85                return PCIBIOS_SUCCESSFUL;
  86
  87        case XEN_PCI_ERR_dev_not_found:
  88                return PCIBIOS_DEVICE_NOT_FOUND;
  89
  90        case XEN_PCI_ERR_invalid_offset:
  91        case XEN_PCI_ERR_op_failed:
  92                return PCIBIOS_BAD_REGISTER_NUMBER;
  93
  94        case XEN_PCI_ERR_not_implemented:
  95                return PCIBIOS_FUNC_NOT_SUPPORTED;
  96
  97        case XEN_PCI_ERR_access_denied:
  98                return PCIBIOS_SET_FAILED;
  99        }
 100        return errno;
 101}
 102
 103static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev)
 104{
 105        if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
 106                && !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) {
 107                dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n");
 108                schedule_work(&pdev->op_work);
 109        }
 110}
 111
 112static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 113{
 114        int err = 0;
 115        struct xen_pci_op *active_op = &pdev->sh_info->op;
 116        unsigned long irq_flags;
 117        evtchn_port_t port = pdev->evtchn;
 118        unsigned irq = pdev->irq;
 119        s64 ns, ns_timeout;
 120
 121        spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
 122
 123        memcpy(active_op, op, sizeof(struct xen_pci_op));
 124
 125        /* Go */
 126        wmb();
 127        set_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
 128        notify_remote_via_evtchn(port);
 129
 130        /*
 131         * We set a poll timeout of 3 seconds but give up on return after
 132         * 2 seconds. It is better to time out too late rather than too early
 133         * (in the latter case we end up continually re-executing poll() with a
 134         * timeout in the past). 1s difference gives plenty of slack for error.
 135         */
 136        ns_timeout = ktime_get_ns() + 2 * (s64)NSEC_PER_SEC;
 137
 138        xen_clear_irq_pending(irq);
 139
 140        while (test_bit(_XEN_PCIF_active,
 141                        (unsigned long *)&pdev->sh_info->flags)) {
 142                xen_poll_irq_timeout(irq, jiffies + 3*HZ);
 143                xen_clear_irq_pending(irq);
 144                ns = ktime_get_ns();
 145                if (ns > ns_timeout) {
 146                        dev_err(&pdev->xdev->dev,
 147                                "pciback not responding!!!\n");
 148                        clear_bit(_XEN_PCIF_active,
 149                                  (unsigned long *)&pdev->sh_info->flags);
 150                        err = XEN_PCI_ERR_dev_not_found;
 151                        goto out;
 152                }
 153        }
 154
 155        /*
 156        * We might lose backend service request since we
 157        * reuse same evtchn with pci_conf backend response. So re-schedule
 158        * aer pcifront service.
 159        */
 160        if (test_bit(_XEN_PCIB_active,
 161                        (unsigned long *)&pdev->sh_info->flags)) {
 162                dev_err(&pdev->xdev->dev,
 163                        "schedule aer pcifront service\n");
 164                schedule_pcifront_aer_op(pdev);
 165        }
 166
 167        memcpy(op, active_op, sizeof(struct xen_pci_op));
 168
 169        err = op->err;
 170out:
 171        spin_unlock_irqrestore(&pdev->sh_info_lock, irq_flags);
 172        return err;
 173}
 174
 175/* Access to this function is spinlocked in drivers/pci/access.c */
 176static int pcifront_bus_read(struct pci_bus *bus, unsigned int devfn,
 177                             int where, int size, u32 *val)
 178{
 179        int err = 0;
 180        struct xen_pci_op op = {
 181                .cmd    = XEN_PCI_OP_conf_read,
 182                .domain = pci_domain_nr(bus),
 183                .bus    = bus->number,
 184                .devfn  = devfn,
 185                .offset = where,
 186                .size   = size,
 187        };
 188        struct pcifront_sd *sd = bus->sysdata;
 189        struct pcifront_device *pdev = pcifront_get_pdev(sd);
 190
 191        dev_dbg(&pdev->xdev->dev,
 192                "read dev=%04x:%02x:%02x.%d - offset %x size %d\n",
 193                pci_domain_nr(bus), bus->number, PCI_SLOT(devfn),
 194                PCI_FUNC(devfn), where, size);
 195
 196        err = do_pci_op(pdev, &op);
 197
 198        if (likely(!err)) {
 199                dev_dbg(&pdev->xdev->dev, "read got back value %x\n",
 200                        op.value);
 201
 202                *val = op.value;
 203        } else if (err == -ENODEV) {
 204                /* No device here, pretend that it just returned 0 */
 205                err = 0;
 206                *val = 0;
 207        }
 208
 209        return errno_to_pcibios_err(err);
 210}
 211
 212/* Access to this function is spinlocked in drivers/pci/access.c */
 213static int pcifront_bus_write(struct pci_bus *bus, unsigned int devfn,
 214                              int where, int size, u32 val)
 215{
 216        struct xen_pci_op op = {
 217                .cmd    = XEN_PCI_OP_conf_write,
 218                .domain = pci_domain_nr(bus),
 219                .bus    = bus->number,
 220                .devfn  = devfn,
 221                .offset = where,
 222                .size   = size,
 223                .value  = val,
 224        };
 225        struct pcifront_sd *sd = bus->sysdata;
 226        struct pcifront_device *pdev = pcifront_get_pdev(sd);
 227
 228        dev_dbg(&pdev->xdev->dev,
 229                "write dev=%04x:%02x:%02x.%d - offset %x size %d val %x\n",
 230                pci_domain_nr(bus), bus->number,
 231                PCI_SLOT(devfn), PCI_FUNC(devfn), where, size, val);
 232
 233        return errno_to_pcibios_err(do_pci_op(pdev, &op));
 234}
 235
 236static struct pci_ops pcifront_bus_ops = {
 237        .read = pcifront_bus_read,
 238        .write = pcifront_bus_write,
 239};
 240
 241#ifdef CONFIG_PCI_MSI
 242static int pci_frontend_enable_msix(struct pci_dev *dev,
 243                                    int vector[], int nvec)
 244{
 245        int err;
 246        int i;
 247        struct xen_pci_op op = {
 248                .cmd    = XEN_PCI_OP_enable_msix,
 249                .domain = pci_domain_nr(dev->bus),
 250                .bus = dev->bus->number,
 251                .devfn = dev->devfn,
 252                .value = nvec,
 253        };
 254        struct pcifront_sd *sd = dev->bus->sysdata;
 255        struct pcifront_device *pdev = pcifront_get_pdev(sd);
 256        struct msi_desc *entry;
 257
 258        if (nvec > SH_INFO_MAX_VEC) {
 259                pci_err(dev, "too many vectors (0x%x) for PCI frontend:"
 260                                   " Increase SH_INFO_MAX_VEC\n", nvec);
 261                return -EINVAL;
 262        }
 263
 264        i = 0;
 265        for_each_pci_msi_entry(entry, dev) {
 266                op.msix_entries[i].entry = entry->msi_attrib.entry_nr;
 267                /* Vector is useless at this point. */
 268                op.msix_entries[i].vector = -1;
 269                i++;
 270        }
 271
 272        err = do_pci_op(pdev, &op);
 273
 274        if (likely(!err)) {
 275                if (likely(!op.value)) {
 276                        /* we get the result */
 277                        for (i = 0; i < nvec; i++) {
 278                                if (op.msix_entries[i].vector <= 0) {
 279                                        pci_warn(dev, "MSI-X entry %d is invalid: %d!\n",
 280                                                i, op.msix_entries[i].vector);
 281                                        err = -EINVAL;
 282                                        vector[i] = -1;
 283                                        continue;
 284                                }
 285                                vector[i] = op.msix_entries[i].vector;
 286                        }
 287                } else {
 288                        pr_info("enable msix get value %x\n", op.value);
 289                        err = op.value;
 290                }
 291        } else {
 292                pci_err(dev, "enable msix get err %x\n", err);
 293        }
 294        return err;
 295}
 296
 297static void pci_frontend_disable_msix(struct pci_dev *dev)
 298{
 299        int err;
 300        struct xen_pci_op op = {
 301                .cmd    = XEN_PCI_OP_disable_msix,
 302                .domain = pci_domain_nr(dev->bus),
 303                .bus = dev->bus->number,
 304                .devfn = dev->devfn,
 305        };
 306        struct pcifront_sd *sd = dev->bus->sysdata;
 307        struct pcifront_device *pdev = pcifront_get_pdev(sd);
 308
 309        err = do_pci_op(pdev, &op);
 310
 311        /* What should do for error ? */
 312        if (err)
 313                pci_err(dev, "pci_disable_msix get err %x\n", err);
 314}
 315
 316static int pci_frontend_enable_msi(struct pci_dev *dev, int vector[])
 317{
 318        int err;
 319        struct xen_pci_op op = {
 320                .cmd    = XEN_PCI_OP_enable_msi,
 321                .domain = pci_domain_nr(dev->bus),
 322                .bus = dev->bus->number,
 323                .devfn = dev->devfn,
 324        };
 325        struct pcifront_sd *sd = dev->bus->sysdata;
 326        struct pcifront_device *pdev = pcifront_get_pdev(sd);
 327
 328        err = do_pci_op(pdev, &op);
 329        if (likely(!err)) {
 330                vector[0] = op.value;
 331                if (op.value <= 0) {
 332                        pci_warn(dev, "MSI entry is invalid: %d!\n",
 333                                op.value);
 334                        err = -EINVAL;
 335                        vector[0] = -1;
 336                }
 337        } else {
 338                pci_err(dev, "pci frontend enable msi failed for dev "
 339                                    "%x:%x\n", op.bus, op.devfn);
 340                err = -EINVAL;
 341        }
 342        return err;
 343}
 344
 345static void pci_frontend_disable_msi(struct pci_dev *dev)
 346{
 347        int err;
 348        struct xen_pci_op op = {
 349                .cmd    = XEN_PCI_OP_disable_msi,
 350                .domain = pci_domain_nr(dev->bus),
 351                .bus = dev->bus->number,
 352                .devfn = dev->devfn,
 353        };
 354        struct pcifront_sd *sd = dev->bus->sysdata;
 355        struct pcifront_device *pdev = pcifront_get_pdev(sd);
 356
 357        err = do_pci_op(pdev, &op);
 358        if (err == XEN_PCI_ERR_dev_not_found) {
 359                /* XXX No response from backend, what shall we do? */
 360                pr_info("get no response from backend for disable MSI\n");
 361                return;
 362        }
 363        if (err)
 364                /* how can pciback notify us fail? */
 365                pr_info("get fake response from backend\n");
 366}
 367
 368static struct xen_pci_frontend_ops pci_frontend_ops = {
 369        .enable_msi = pci_frontend_enable_msi,
 370        .disable_msi = pci_frontend_disable_msi,
 371        .enable_msix = pci_frontend_enable_msix,
 372        .disable_msix = pci_frontend_disable_msix,
 373};
 374
 375static void pci_frontend_registrar(int enable)
 376{
 377        if (enable)
 378                xen_pci_frontend = &pci_frontend_ops;
 379        else
 380                xen_pci_frontend = NULL;
 381};
 382#else
 383static inline void pci_frontend_registrar(int enable) { };
 384#endif /* CONFIG_PCI_MSI */
 385
 386/* Claim resources for the PCI frontend as-is, backend won't allow changes */
 387static int pcifront_claim_resource(struct pci_dev *dev, void *data)
 388{
 389        struct pcifront_device *pdev = data;
 390        int i;
 391        struct resource *r;
 392
 393        for (i = 0; i < PCI_NUM_RESOURCES; i++) {
 394                r = &dev->resource[i];
 395
 396                if (!r->parent && r->start && r->flags) {
 397                        dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n",
 398                                pci_name(dev), i);
 399                        if (pci_claim_resource(dev, i)) {
 400                                dev_err(&pdev->xdev->dev, "Could not claim resource %s/%d! "
 401                                        "Device offline. Try using e820_host=1 in the guest config.\n",
 402                                        pci_name(dev), i);
 403                        }
 404                }
 405        }
 406
 407        return 0;
 408}
 409
 410static int pcifront_scan_bus(struct pcifront_device *pdev,
 411                                unsigned int domain, unsigned int bus,
 412                                struct pci_bus *b)
 413{
 414        struct pci_dev *d;
 415        unsigned int devfn;
 416
 417        /* Scan the bus for functions and add.
 418         * We omit handling of PCI bridge attachment because pciback prevents
 419         * bridges from being exported.
 420         */
 421        for (devfn = 0; devfn < 0x100; devfn++) {
 422                d = pci_get_slot(b, devfn);
 423                if (d) {
 424                        /* Device is already known. */
 425                        pci_dev_put(d);
 426                        continue;
 427                }
 428
 429                d = pci_scan_single_device(b, devfn);
 430                if (d)
 431                        dev_info(&pdev->xdev->dev, "New device on "
 432                                 "%04x:%02x:%02x.%d found.\n", domain, bus,
 433                                 PCI_SLOT(devfn), PCI_FUNC(devfn));
 434        }
 435
 436        return 0;
 437}
 438
 439static int pcifront_scan_root(struct pcifront_device *pdev,
 440                                 unsigned int domain, unsigned int bus)
 441{
 442        struct pci_bus *b;
 443        LIST_HEAD(resources);
 444        struct pcifront_sd *sd = NULL;
 445        struct pci_bus_entry *bus_entry = NULL;
 446        int err = 0;
 447        static struct resource busn_res = {
 448                .start = 0,
 449                .end = 255,
 450                .flags = IORESOURCE_BUS,
 451        };
 452
 453#ifndef CONFIG_PCI_DOMAINS
 454        if (domain != 0) {
 455                dev_err(&pdev->xdev->dev,
 456                        "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 457                dev_err(&pdev->xdev->dev,
 458                        "Please compile with CONFIG_PCI_DOMAINS\n");
 459                err = -EINVAL;
 460                goto err_out;
 461        }
 462#endif
 463
 464        dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n",
 465                 domain, bus);
 466
 467        bus_entry = kzalloc(sizeof(*bus_entry), GFP_KERNEL);
 468        sd = kzalloc(sizeof(*sd), GFP_KERNEL);
 469        if (!bus_entry || !sd) {
 470                err = -ENOMEM;
 471                goto err_out;
 472        }
 473        pci_add_resource(&resources, &ioport_resource);
 474        pci_add_resource(&resources, &iomem_resource);
 475        pci_add_resource(&resources, &busn_res);
 476        pcifront_init_sd(sd, domain, bus, pdev);
 477
 478        pci_lock_rescan_remove();
 479
 480        b = pci_scan_root_bus(&pdev->xdev->dev, bus,
 481                                  &pcifront_bus_ops, sd, &resources);
 482        if (!b) {
 483                dev_err(&pdev->xdev->dev,
 484                        "Error creating PCI Frontend Bus!\n");
 485                err = -ENOMEM;
 486                pci_unlock_rescan_remove();
 487                pci_free_resource_list(&resources);
 488                goto err_out;
 489        }
 490
 491        bus_entry->bus = b;
 492
 493        list_add(&bus_entry->list, &pdev->root_buses);
 494
 495        /* pci_scan_root_bus skips devices which do not have a
 496        * devfn==0. The pcifront_scan_bus enumerates all devfn. */
 497        err = pcifront_scan_bus(pdev, domain, bus, b);
 498
 499        /* Claim resources before going "live" with our devices */
 500        pci_walk_bus(b, pcifront_claim_resource, pdev);
 501
 502        /* Create SysFS and notify udev of the devices. Aka: "going live" */
 503        pci_bus_add_devices(b);
 504
 505        pci_unlock_rescan_remove();
 506        return err;
 507
 508err_out:
 509        kfree(bus_entry);
 510        kfree(sd);
 511
 512        return err;
 513}
 514
 515static int pcifront_rescan_root(struct pcifront_device *pdev,
 516                                   unsigned int domain, unsigned int bus)
 517{
 518        int err;
 519        struct pci_bus *b;
 520
 521#ifndef CONFIG_PCI_DOMAINS
 522        if (domain != 0) {
 523                dev_err(&pdev->xdev->dev,
 524                        "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
 525                dev_err(&pdev->xdev->dev,
 526                        "Please compile with CONFIG_PCI_DOMAINS\n");
 527                return -EINVAL;
 528        }
 529#endif
 530
 531        dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
 532                 domain, bus);
 533
 534        b = pci_find_bus(domain, bus);
 535        if (!b)
 536                /* If the bus is unknown, create it. */
 537                return pcifront_scan_root(pdev, domain, bus);
 538
 539        err = pcifront_scan_bus(pdev, domain, bus, b);
 540
 541        /* Claim resources before going "live" with our devices */
 542        pci_walk_bus(b, pcifront_claim_resource, pdev);
 543
 544        /* Create SysFS and notify udev of the devices. Aka: "going live" */
 545        pci_bus_add_devices(b);
 546
 547        return err;
 548}
 549
 550static void free_root_bus_devs(struct pci_bus *bus)
 551{
 552        struct pci_dev *dev;
 553
 554        while (!list_empty(&bus->devices)) {
 555                dev = container_of(bus->devices.next, struct pci_dev,
 556                                   bus_list);
 557                pci_dbg(dev, "removing device\n");
 558                pci_stop_and_remove_bus_device(dev);
 559        }
 560}
 561
 562static void pcifront_free_roots(struct pcifront_device *pdev)
 563{
 564        struct pci_bus_entry *bus_entry, *t;
 565
 566        dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n");
 567
 568        pci_lock_rescan_remove();
 569        list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) {
 570                list_del(&bus_entry->list);
 571
 572                free_root_bus_devs(bus_entry->bus);
 573
 574                kfree(bus_entry->bus->sysdata);
 575
 576                device_unregister(bus_entry->bus->bridge);
 577                pci_remove_bus(bus_entry->bus);
 578
 579                kfree(bus_entry);
 580        }
 581        pci_unlock_rescan_remove();
 582}
 583
 584static pci_ers_result_t pcifront_common_process(int cmd,
 585                                                struct pcifront_device *pdev,
 586                                                pci_channel_state_t state)
 587{
 588        pci_ers_result_t result;
 589        struct pci_driver *pdrv;
 590        int bus = pdev->sh_info->aer_op.bus;
 591        int devfn = pdev->sh_info->aer_op.devfn;
 592        int domain = pdev->sh_info->aer_op.domain;
 593        struct pci_dev *pcidev;
 594        int flag = 0;
 595
 596        dev_dbg(&pdev->xdev->dev,
 597                "pcifront AER process: cmd %x (bus:%x, devfn%x)",
 598                cmd, bus, devfn);
 599        result = PCI_ERS_RESULT_NONE;
 600
 601        pcidev = pci_get_domain_bus_and_slot(domain, bus, devfn);
 602        if (!pcidev || !pcidev->driver) {
 603                dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
 604                pci_dev_put(pcidev);
 605                return result;
 606        }
 607        pdrv = pcidev->driver;
 608
 609        if (pdrv) {
 610                if (pdrv->err_handler && pdrv->err_handler->error_detected) {
 611                        pci_dbg(pcidev, "trying to call AER service\n");
 612                        if (pcidev) {
 613                                flag = 1;
 614                                switch (cmd) {
 615                                case XEN_PCI_OP_aer_detected:
 616                                        result = pdrv->err_handler->
 617                                                 error_detected(pcidev, state);
 618                                        break;
 619                                case XEN_PCI_OP_aer_mmio:
 620                                        result = pdrv->err_handler->
 621                                                 mmio_enabled(pcidev);
 622                                        break;
 623                                case XEN_PCI_OP_aer_slotreset:
 624                                        result = pdrv->err_handler->
 625                                                 slot_reset(pcidev);
 626                                        break;
 627                                case XEN_PCI_OP_aer_resume:
 628                                        pdrv->err_handler->resume(pcidev);
 629                                        break;
 630                                default:
 631                                        dev_err(&pdev->xdev->dev,
 632                                                "bad request in aer recovery "
 633                                                "operation!\n");
 634
 635                                }
 636                        }
 637                }
 638        }
 639        if (!flag)
 640                result = PCI_ERS_RESULT_NONE;
 641
 642        return result;
 643}
 644
 645
 646static void pcifront_do_aer(struct work_struct *data)
 647{
 648        struct pcifront_device *pdev =
 649                container_of(data, struct pcifront_device, op_work);
 650        int cmd = pdev->sh_info->aer_op.cmd;
 651        pci_channel_state_t state =
 652                (pci_channel_state_t)pdev->sh_info->aer_op.err;
 653
 654        /*If a pci_conf op is in progress,
 655                we have to wait until it is done before service aer op*/
 656        dev_dbg(&pdev->xdev->dev,
 657                "pcifront service aer bus %x devfn %x\n",
 658                pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn);
 659
 660        pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state);
 661
 662        /* Post the operation to the guest. */
 663        wmb();
 664        clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags);
 665        notify_remote_via_evtchn(pdev->evtchn);
 666
 667        /*in case of we lost an aer request in four lines time_window*/
 668        smp_mb__before_atomic();
 669        clear_bit(_PDEVB_op_active, &pdev->flags);
 670        smp_mb__after_atomic();
 671
 672        schedule_pcifront_aer_op(pdev);
 673
 674}
 675
 676static irqreturn_t pcifront_handler_aer(int irq, void *dev)
 677{
 678        struct pcifront_device *pdev = dev;
 679        schedule_pcifront_aer_op(pdev);
 680        return IRQ_HANDLED;
 681}
 682static int pcifront_connect_and_init_dma(struct pcifront_device *pdev)
 683{
 684        int err = 0;
 685
 686        spin_lock(&pcifront_dev_lock);
 687
 688        if (!pcifront_dev) {
 689                dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
 690                pcifront_dev = pdev;
 691        } else
 692                err = -EEXIST;
 693
 694        spin_unlock(&pcifront_dev_lock);
 695
 696        if (!err && !is_swiotlb_active()) {
 697                err = pci_xen_swiotlb_init_late();
 698                if (err)
 699                        dev_err(&pdev->xdev->dev, "Could not setup SWIOTLB!\n");
 700        }
 701        return err;
 702}
 703
 704static void pcifront_disconnect(struct pcifront_device *pdev)
 705{
 706        spin_lock(&pcifront_dev_lock);
 707
 708        if (pdev == pcifront_dev) {
 709                dev_info(&pdev->xdev->dev,
 710                         "Disconnecting PCI Frontend Buses\n");
 711                pcifront_dev = NULL;
 712        }
 713
 714        spin_unlock(&pcifront_dev_lock);
 715}
 716static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev)
 717{
 718        struct pcifront_device *pdev;
 719
 720        pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL);
 721        if (pdev == NULL)
 722                goto out;
 723
 724        pdev->sh_info =
 725            (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL);
 726        if (pdev->sh_info == NULL) {
 727                kfree(pdev);
 728                pdev = NULL;
 729                goto out;
 730        }
 731        pdev->sh_info->flags = 0;
 732
 733        /*Flag for registering PV AER handler*/
 734        set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags);
 735
 736        dev_set_drvdata(&xdev->dev, pdev);
 737        pdev->xdev = xdev;
 738
 739        INIT_LIST_HEAD(&pdev->root_buses);
 740
 741        spin_lock_init(&pdev->sh_info_lock);
 742
 743        pdev->evtchn = INVALID_EVTCHN;
 744        pdev->gnt_ref = INVALID_GRANT_REF;
 745        pdev->irq = -1;
 746
 747        INIT_WORK(&pdev->op_work, pcifront_do_aer);
 748
 749        dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n",
 750                pdev, pdev->sh_info);
 751out:
 752        return pdev;
 753}
 754
 755static void free_pdev(struct pcifront_device *pdev)
 756{
 757        dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
 758
 759        pcifront_free_roots(pdev);
 760
 761        cancel_work_sync(&pdev->op_work);
 762
 763        if (pdev->irq >= 0)
 764                unbind_from_irqhandler(pdev->irq, pdev);
 765
 766        if (pdev->evtchn != INVALID_EVTCHN)
 767                xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
 768
 769        if (pdev->gnt_ref != INVALID_GRANT_REF)
 770                gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
 771                                          (unsigned long)pdev->sh_info);
 772        else
 773                free_page((unsigned long)pdev->sh_info);
 774
 775        dev_set_drvdata(&pdev->xdev->dev, NULL);
 776
 777        kfree(pdev);
 778}
 779
 780static int pcifront_publish_info(struct pcifront_device *pdev)
 781{
 782        int err = 0;
 783        struct xenbus_transaction trans;
 784        grant_ref_t gref;
 785
 786        err = xenbus_grant_ring(pdev->xdev, pdev->sh_info, 1, &gref);
 787        if (err < 0)
 788                goto out;
 789
 790        pdev->gnt_ref = gref;
 791
 792        err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
 793        if (err)
 794                goto out;
 795
 796        err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer,
 797                0, "pcifront", pdev);
 798
 799        if (err < 0)
 800                return err;
 801
 802        pdev->irq = err;
 803
 804do_publish:
 805        err = xenbus_transaction_start(&trans);
 806        if (err) {
 807                xenbus_dev_fatal(pdev->xdev, err,
 808                                 "Error writing configuration for backend "
 809                                 "(start transaction)");
 810                goto out;
 811        }
 812
 813        err = xenbus_printf(trans, pdev->xdev->nodename,
 814                            "pci-op-ref", "%u", pdev->gnt_ref);
 815        if (!err)
 816                err = xenbus_printf(trans, pdev->xdev->nodename,
 817                                    "event-channel", "%u", pdev->evtchn);
 818        if (!err)
 819                err = xenbus_printf(trans, pdev->xdev->nodename,
 820                                    "magic", XEN_PCI_MAGIC);
 821
 822        if (err) {
 823                xenbus_transaction_end(trans, 1);
 824                xenbus_dev_fatal(pdev->xdev, err,
 825                                 "Error writing configuration for backend");
 826                goto out;
 827        } else {
 828                err = xenbus_transaction_end(trans, 0);
 829                if (err == -EAGAIN)
 830                        goto do_publish;
 831                else if (err) {
 832                        xenbus_dev_fatal(pdev->xdev, err,
 833                                         "Error completing transaction "
 834                                         "for backend");
 835                        goto out;
 836                }
 837        }
 838
 839        xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
 840
 841        dev_dbg(&pdev->xdev->dev, "publishing successful!\n");
 842
 843out:
 844        return err;
 845}
 846
 847static int pcifront_try_connect(struct pcifront_device *pdev)
 848{
 849        int err = -EFAULT;
 850        int i, num_roots, len;
 851        char str[64];
 852        unsigned int domain, bus;
 853
 854
 855        /* Only connect once */
 856        if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 857            XenbusStateInitialised)
 858                goto out;
 859
 860        err = pcifront_connect_and_init_dma(pdev);
 861        if (err && err != -EEXIST) {
 862                xenbus_dev_fatal(pdev->xdev, err,
 863                                 "Error setting up PCI Frontend");
 864                goto out;
 865        }
 866
 867        err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 868                           "root_num", "%d", &num_roots);
 869        if (err == -ENOENT) {
 870                xenbus_dev_error(pdev->xdev, err,
 871                                 "No PCI Roots found, trying 0000:00");
 872                err = pcifront_scan_root(pdev, 0, 0);
 873                if (err) {
 874                        xenbus_dev_fatal(pdev->xdev, err,
 875                                         "Error scanning PCI root 0000:00");
 876                        goto out;
 877                }
 878                num_roots = 0;
 879        } else if (err != 1) {
 880                if (err == 0)
 881                        err = -EINVAL;
 882                xenbus_dev_fatal(pdev->xdev, err,
 883                                 "Error reading number of PCI roots");
 884                goto out;
 885        }
 886
 887        for (i = 0; i < num_roots; i++) {
 888                len = snprintf(str, sizeof(str), "root-%d", i);
 889                if (unlikely(len >= (sizeof(str) - 1))) {
 890                        err = -ENOMEM;
 891                        goto out;
 892                }
 893
 894                err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 895                                   "%x:%x", &domain, &bus);
 896                if (err != 2) {
 897                        if (err >= 0)
 898                                err = -EINVAL;
 899                        xenbus_dev_fatal(pdev->xdev, err,
 900                                         "Error reading PCI root %d", i);
 901                        goto out;
 902                }
 903
 904                err = pcifront_scan_root(pdev, domain, bus);
 905                if (err) {
 906                        xenbus_dev_fatal(pdev->xdev, err,
 907                                         "Error scanning PCI root %04x:%02x",
 908                                         domain, bus);
 909                        goto out;
 910                }
 911        }
 912
 913        err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 914
 915out:
 916        return err;
 917}
 918
 919static int pcifront_try_disconnect(struct pcifront_device *pdev)
 920{
 921        int err = 0;
 922        enum xenbus_state prev_state;
 923
 924
 925        prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
 926
 927        if (prev_state >= XenbusStateClosing)
 928                goto out;
 929
 930        if (prev_state == XenbusStateConnected) {
 931                pcifront_free_roots(pdev);
 932                pcifront_disconnect(pdev);
 933        }
 934
 935        err = xenbus_switch_state(pdev->xdev, XenbusStateClosed);
 936
 937out:
 938
 939        return err;
 940}
 941
 942static int pcifront_attach_devices(struct pcifront_device *pdev)
 943{
 944        int err = -EFAULT;
 945        int i, num_roots, len;
 946        unsigned int domain, bus;
 947        char str[64];
 948
 949        if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 950            XenbusStateReconfiguring)
 951                goto out;
 952
 953        err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
 954                           "root_num", "%d", &num_roots);
 955        if (err == -ENOENT) {
 956                xenbus_dev_error(pdev->xdev, err,
 957                                 "No PCI Roots found, trying 0000:00");
 958                err = pcifront_rescan_root(pdev, 0, 0);
 959                if (err) {
 960                        xenbus_dev_fatal(pdev->xdev, err,
 961                                         "Error scanning PCI root 0000:00");
 962                        goto out;
 963                }
 964                num_roots = 0;
 965        } else if (err != 1) {
 966                if (err == 0)
 967                        err = -EINVAL;
 968                xenbus_dev_fatal(pdev->xdev, err,
 969                                 "Error reading number of PCI roots");
 970                goto out;
 971        }
 972
 973        for (i = 0; i < num_roots; i++) {
 974                len = snprintf(str, sizeof(str), "root-%d", i);
 975                if (unlikely(len >= (sizeof(str) - 1))) {
 976                        err = -ENOMEM;
 977                        goto out;
 978                }
 979
 980                err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
 981                                   "%x:%x", &domain, &bus);
 982                if (err != 2) {
 983                        if (err >= 0)
 984                                err = -EINVAL;
 985                        xenbus_dev_fatal(pdev->xdev, err,
 986                                         "Error reading PCI root %d", i);
 987                        goto out;
 988                }
 989
 990                err = pcifront_rescan_root(pdev, domain, bus);
 991                if (err) {
 992                        xenbus_dev_fatal(pdev->xdev, err,
 993                                         "Error scanning PCI root %04x:%02x",
 994                                         domain, bus);
 995                        goto out;
 996                }
 997        }
 998
 999        xenbus_switch_state(pdev->xdev, XenbusStateConnected);
1000
1001out:
1002        return err;
1003}
1004
1005static int pcifront_detach_devices(struct pcifront_device *pdev)
1006{
1007        int err = 0;
1008        int i, num_devs;
1009        unsigned int domain, bus, slot, func;
1010        struct pci_dev *pci_dev;
1011        char str[64];
1012
1013        if (xenbus_read_driver_state(pdev->xdev->nodename) !=
1014            XenbusStateConnected)
1015                goto out;
1016
1017        err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d",
1018                           &num_devs);
1019        if (err != 1) {
1020                if (err >= 0)
1021                        err = -EINVAL;
1022                xenbus_dev_fatal(pdev->xdev, err,
1023                                 "Error reading number of PCI devices");
1024                goto out;
1025        }
1026
1027        /* Find devices being detached and remove them. */
1028        for (i = 0; i < num_devs; i++) {
1029                int l, state;
1030                l = snprintf(str, sizeof(str), "state-%d", i);
1031                if (unlikely(l >= (sizeof(str) - 1))) {
1032                        err = -ENOMEM;
1033                        goto out;
1034                }
1035                state = xenbus_read_unsigned(pdev->xdev->otherend, str,
1036                                             XenbusStateUnknown);
1037
1038                if (state != XenbusStateClosing)
1039                        continue;
1040
1041                /* Remove device. */
1042                l = snprintf(str, sizeof(str), "vdev-%d", i);
1043                if (unlikely(l >= (sizeof(str) - 1))) {
1044                        err = -ENOMEM;
1045                        goto out;
1046                }
1047                err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
1048                                   "%x:%x:%x.%x", &domain, &bus, &slot, &func);
1049                if (err != 4) {
1050                        if (err >= 0)
1051                                err = -EINVAL;
1052                        xenbus_dev_fatal(pdev->xdev, err,
1053                                         "Error reading PCI device %d", i);
1054                        goto out;
1055                }
1056
1057                pci_dev = pci_get_domain_bus_and_slot(domain, bus,
1058                                PCI_DEVFN(slot, func));
1059                if (!pci_dev) {
1060                        dev_dbg(&pdev->xdev->dev,
1061                                "Cannot get PCI device %04x:%02x:%02x.%d\n",
1062                                domain, bus, slot, func);
1063                        continue;
1064                }
1065                pci_lock_rescan_remove();
1066                pci_stop_and_remove_bus_device(pci_dev);
1067                pci_dev_put(pci_dev);
1068                pci_unlock_rescan_remove();
1069
1070                dev_dbg(&pdev->xdev->dev,
1071                        "PCI device %04x:%02x:%02x.%d removed.\n",
1072                        domain, bus, slot, func);
1073        }
1074
1075        err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring);
1076
1077out:
1078        return err;
1079}
1080
1081static void __ref pcifront_backend_changed(struct xenbus_device *xdev,
1082                                                  enum xenbus_state be_state)
1083{
1084        struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1085
1086        switch (be_state) {
1087        case XenbusStateUnknown:
1088        case XenbusStateInitialising:
1089        case XenbusStateInitWait:
1090        case XenbusStateInitialised:
1091                break;
1092
1093        case XenbusStateConnected:
1094                pcifront_try_connect(pdev);
1095                break;
1096
1097        case XenbusStateClosed:
1098                if (xdev->state == XenbusStateClosed)
1099                        break;
1100                fallthrough;    /* Missed the backend's CLOSING state */
1101        case XenbusStateClosing:
1102                dev_warn(&xdev->dev, "backend going away!\n");
1103                pcifront_try_disconnect(pdev);
1104                break;
1105
1106        case XenbusStateReconfiguring:
1107                pcifront_detach_devices(pdev);
1108                break;
1109
1110        case XenbusStateReconfigured:
1111                pcifront_attach_devices(pdev);
1112                break;
1113        }
1114}
1115
1116static int pcifront_xenbus_probe(struct xenbus_device *xdev,
1117                                 const struct xenbus_device_id *id)
1118{
1119        int err = 0;
1120        struct pcifront_device *pdev = alloc_pdev(xdev);
1121
1122        if (pdev == NULL) {
1123                err = -ENOMEM;
1124                xenbus_dev_fatal(xdev, err,
1125                                 "Error allocating pcifront_device struct");
1126                goto out;
1127        }
1128
1129        err = pcifront_publish_info(pdev);
1130        if (err)
1131                free_pdev(pdev);
1132
1133out:
1134        return err;
1135}
1136
1137static int pcifront_xenbus_remove(struct xenbus_device *xdev)
1138{
1139        struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1140        if (pdev)
1141                free_pdev(pdev);
1142
1143        return 0;
1144}
1145
1146static const struct xenbus_device_id xenpci_ids[] = {
1147        {"pci"},
1148        {""},
1149};
1150
1151static struct xenbus_driver xenpci_driver = {
1152        .name                   = "pcifront",
1153        .ids                    = xenpci_ids,
1154        .probe                  = pcifront_xenbus_probe,
1155        .remove                 = pcifront_xenbus_remove,
1156        .otherend_changed       = pcifront_backend_changed,
1157};
1158
1159static int __init pcifront_init(void)
1160{
1161        if (!xen_pv_domain() || xen_initial_domain())
1162                return -ENODEV;
1163
1164        if (!xen_has_pv_devices())
1165                return -ENODEV;
1166
1167        pci_frontend_registrar(1 /* enable */);
1168
1169        return xenbus_register_frontend(&xenpci_driver);
1170}
1171
1172static void __exit pcifront_cleanup(void)
1173{
1174        xenbus_unregister_driver(&xenpci_driver);
1175        pci_frontend_registrar(0 /* disable */);
1176}
1177module_init(pcifront_init);
1178module_exit(pcifront_cleanup);
1179
1180MODULE_DESCRIPTION("Xen PCI passthrough frontend.");
1181MODULE_LICENSE("GPL");
1182MODULE_ALIAS("xen:pci");
1183