hw/acpi/pcihp.c

   1 /*
   2  * QEMU<->ACPI BIOS PCI hotplug interface
   3  *
   4  * QEMU supports PCI hotplug via ACPI. This module
   5  * implements the interface between QEMU and the ACPI BIOS.
   6  * Interface specification - see docs/specs/acpi_pci_hotplug.txt
   7  *
   8  * Copyright (c) 2013, Red Hat Inc, Michael S. Tsirkin (mst@redhat.com)
   9  * Copyright (c) 2006 Fabrice Bellard
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License version 2.1 as published by the Free Software Foundation.
  14  *
  15  * This library is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with this library; if not, see <http://www.gnu.org/licenses/>
  22  *
  23  * Contributions after 2012-01-13 are licensed under the terms of the
  24  * GNU GPL, version 2 or (at your option) any later version.
  25  */
  26
  27 #include "qemu/osdep.h"
  28 #include "hw/acpi/pcihp.h"
  29
  30 #include "hw/pci-host/i440fx.h"
  31 #include "hw/pci/pci.h"
  32 #include "hw/pci/pci_bridge.h"
  33 #include "hw/acpi/acpi.h"
  34 #include "hw/pci/pci_bus.h"
  35 #include "migration/vmstate.h"
  36 #include "qapi/error.h"
  37 #include "qom/qom-qobject.h"
  38 #include "trace.h"
  39
  40 #define ACPI_PCIHP_ADDR 0xae00
  41 #define ACPI_PCIHP_SIZE 0x0018
  42 #define PCI_UP_BASE 0x0000
  43 #define PCI_DOWN_BASE 0x0004
  44 #define PCI_EJ_BASE 0x0008
  45 #define PCI_RMV_BASE 0x000c
  46 #define PCI_SEL_BASE 0x0010
  47 #define PCI_AIDX_BASE 0x0014
  48
  49 typedef struct AcpiPciHpFind {
  50     int bsel;
  51     PCIBus *bus;
  52 } AcpiPciHpFind;
  53
  54 static gint g_cmp_uint32(gconstpointer a, gconstpointer b, gpointer user_data)
  55 {
  56     return a - b;
  57 }
  58
  59 static GSequence *pci_acpi_index_list(void)
  60 {
  61     static GSequence *used_acpi_index_list;
  62
  63     if (!used_acpi_index_list) {
  64         used_acpi_index_list = g_sequence_new(NULL);
  65     }
  66     return used_acpi_index_list;
  67 }
  68
  69 static int acpi_pcihp_get_bsel(PCIBus *bus)
  70 {
  71     Error *local_err = NULL;
  72     uint64_t bsel = object_property_get_uint(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
  73                                              &local_err);
  74
  75     if (local_err || bsel >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
  76         if (local_err) {
  77             error_free(local_err);
  78         }
  79         return -1;
  80     } else {
  81         return bsel;
  82     }
  83 }
  84
  85 /* Assign BSEL property to all buses.  In the future, this can be changed
  86  * to only assign to buses that support hotplug.
  87  */
  88 static void *acpi_set_bsel(PCIBus *bus, void *opaque)
  89 {
  90     unsigned *bsel_alloc = opaque;
  91     unsigned *bus_bsel;
  92
  93     if (qbus_is_hotpluggable(BUS(bus))) {
  94         bus_bsel = g_malloc(sizeof *bus_bsel);
  95
  96         *bus_bsel = (*bsel_alloc)++;
  97         object_property_add_uint32_ptr(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
  98                                        bus_bsel, OBJ_PROP_FLAG_READ);
  99     }
 100
 101     return bsel_alloc;
 102 }
 103
 104 static void acpi_set_pci_info(void)
 105 {
 106     static bool bsel_is_set;
 107     PCIBus *bus;
 108     unsigned bsel_alloc = ACPI_PCIHP_BSEL_DEFAULT;
 109
 110     if (bsel_is_set) {
 111         return;
 112     }
 113     bsel_is_set = true;
 114
 115     bus = find_i440fx(); /* TODO: Q35 support */
 116     if (bus) {
 117         /* Scan all PCI buses. Set property to enable acpi based hotplug. */
 118         pci_for_each_bus_depth_first(bus, acpi_set_bsel, NULL, &bsel_alloc);
 119     }
 120 }
 121
 122 static void acpi_pcihp_disable_root_bus(void)
 123 {
 124     static bool root_hp_disabled;
 125     PCIBus *bus;
 126
 127     if (root_hp_disabled) {
 128         return;
 129     }
 130
 131     bus = find_i440fx();
 132     if (bus) {
 133         /* setting the hotplug handler to NULL makes the bus non-hotpluggable */
 134         qbus_set_hotplug_handler(BUS(bus), NULL);
 135     }
 136     root_hp_disabled = true;
 137     return;
 138 }
 139
 140 static void acpi_pcihp_test_hotplug_bus(PCIBus *bus, void *opaque)
 141 {
 142     AcpiPciHpFind *find = opaque;
 143     if (find->bsel == acpi_pcihp_get_bsel(bus)) {
 144         find->bus = bus;
 145     }
 146 }
 147
 148 static PCIBus *acpi_pcihp_find_hotplug_bus(AcpiPciHpState *s, int bsel)
 149 {
 150     AcpiPciHpFind find = { .bsel = bsel, .bus = NULL };
 151
 152     if (bsel < 0) {
 153         return NULL;
 154     }
 155
 156     pci_for_each_bus(s->root, acpi_pcihp_test_hotplug_bus, &find);
 157
 158     /* Make bsel 0 eject root bus if bsel property is not set,
 159      * for compatibility with non acpi setups.
 160      * TODO: really needed?
 161      */
 162     if (!bsel && !find.bus) {
 163         find.bus = s->root;
 164     }
 165
 166     /*
 167      * Check if find.bus is actually hotpluggable. If bsel is set to
 168      * NULL for example on the root bus in order to make it
 169      * non-hotpluggable, find.bus will match the root bus when bsel
 170      * is 0. See acpi_pcihp_test_hotplug_bus() above. Since the
 171      * bus is not hotpluggable however, we should not select the bus.
 172      * Instead, we should set find.bus to NULL in that case. In the check
 173      * below, we generalize this case for all buses, not just the root bus.
 174      * The callers of this function check for a null return value and
 175      * handle them appropriately.
 176      */
 177     if (find.bus && !qbus_is_hotpluggable(BUS(find.bus))) {
 178         find.bus = NULL;
 179     }
 180     return find.bus;
 181 }
 182
 183 static bool acpi_pcihp_pc_no_hotplug(AcpiPciHpState *s, PCIDevice *dev)
 184 {
 185     PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(dev);
 186     DeviceClass *dc = DEVICE_GET_CLASS(dev);
 187     /*
 188      * ACPI doesn't allow hotplug of bridge devices.  Don't allow
 189      * hot-unplug of bridge devices unless they were added by hotplug
 190      * (and so, not described by acpi).
 191      */
 192     return (pc->is_bridge && !dev->qdev.hotplugged) || !dc->hotpluggable;
 193 }
 194
 195 static void acpi_pcihp_eject_slot(AcpiPciHpState *s, unsigned bsel, unsigned slots)
 196 {
 197     HotplugHandler *hotplug_ctrl;
 198     BusChild *kid, *next;
 199     int slot = ctz32(slots);
 200     PCIBus *bus = acpi_pcihp_find_hotplug_bus(s, bsel);
 201
 202     trace_acpi_pci_eject_slot(bsel, slot);
 203
 204     if (!bus || slot > 31) {
 205         return;
 206     }
 207
 208     /* Mark request as complete */
 209     s->acpi_pcihp_pci_status[bsel].down &= ~(1U << slot);
 210     s->acpi_pcihp_pci_status[bsel].up &= ~(1U << slot);
 211
 212     QTAILQ_FOREACH_SAFE(kid, &bus->qbus.children, sibling, next) {
 213         DeviceState *qdev = kid->child;
 214         PCIDevice *dev = PCI_DEVICE(qdev);
 215         if (PCI_SLOT(dev->devfn) == slot) {
 216             if (!acpi_pcihp_pc_no_hotplug(s, dev)) {
 217                 hotplug_ctrl = qdev_get_hotplug_handler(qdev);
 218                 hotplug_handler_unplug(hotplug_ctrl, qdev, &error_abort);
 219                 object_unparent(OBJECT(qdev));
 220             }
 221         }
 222     }
 223 }
 224
 225 static void acpi_pcihp_update_hotplug_bus(AcpiPciHpState *s, int bsel)
 226 {
 227     BusChild *kid, *next;
 228     PCIBus *bus = acpi_pcihp_find_hotplug_bus(s, bsel);
 229
 230     /* Execute any pending removes during reset */
 231     while (s->acpi_pcihp_pci_status[bsel].down) {
 232         acpi_pcihp_eject_slot(s, bsel, s->acpi_pcihp_pci_status[bsel].down);
 233     }
 234
 235     s->acpi_pcihp_pci_status[bsel].hotplug_enable = ~0;
 236
 237     if (!bus) {
 238         return;
 239     }
 240     QTAILQ_FOREACH_SAFE(kid, &bus->qbus.children, sibling, next) {
 241         DeviceState *qdev = kid->child;
 242         PCIDevice *pdev = PCI_DEVICE(qdev);
 243         int slot = PCI_SLOT(pdev->devfn);
 244
 245         if (acpi_pcihp_pc_no_hotplug(s, pdev)) {
 246             s->acpi_pcihp_pci_status[bsel].hotplug_enable &= ~(1U << slot);
 247         }
 248     }
 249 }
 250
 251 static void acpi_pcihp_update(AcpiPciHpState *s)
 252 {
 253     int i;
 254
 255     for (i = 0; i < ACPI_PCIHP_MAX_HOTPLUG_BUS; ++i) {
 256         acpi_pcihp_update_hotplug_bus(s, i);
 257     }
 258 }
 259
 260 void acpi_pcihp_reset(AcpiPciHpState *s, bool acpihp_root_off)
 261 {
 262     if (acpihp_root_off) {
 263         acpi_pcihp_disable_root_bus();
 264     }
 265     acpi_set_pci_info();
 266     acpi_pcihp_update(s);
 267 }
 268
 269 #define ONBOARD_INDEX_MAX (16 * 1024 - 1)
 270
 271 void acpi_pcihp_device_pre_plug_cb(HotplugHandler *hotplug_dev,
 272                                    DeviceState *dev, Error **errp)
 273 {
 274     PCIDevice *pdev = PCI_DEVICE(dev);
 275
 276     /* Only hotplugged devices need the hotplug capability. */
 277     if (dev->hotplugged &&
 278         acpi_pcihp_get_bsel(pci_get_bus(PCI_DEVICE(dev))) < 0) {
 279         error_setg(errp, "Unsupported bus. Bus doesn't have property '"
 280                    ACPI_PCIHP_PROP_BSEL "' set");
 281         return;
 282     }
 283
 284     /*
 285      * capped by systemd (see: udev-builtin-net_id.c)
 286      * as it's the only known user honor it to avoid users
 287      * misconfigure QEMU and then wonder why acpi-index doesn't work
 288      */
 289     if (pdev->acpi_index > ONBOARD_INDEX_MAX) {
 290         error_setg(errp, "acpi-index should be less or equal to %u",
 291                    ONBOARD_INDEX_MAX);
 292         return;
 293     }
 294
 295     /*
 296      * make sure that acpi-index is unique across all present PCI devices
 297      */
 298     if (pdev->acpi_index) {
 299         GSequence *used_indexes = pci_acpi_index_list();
 300
 301         if (g_sequence_lookup(used_indexes, GINT_TO_POINTER(pdev->acpi_index),
 302                               g_cmp_uint32, NULL)) {
 303             error_setg(errp, "a PCI device with acpi-index = %" PRIu32
 304                        " already exist", pdev->acpi_index);
 305             return;
 306         }
 307         g_sequence_insert_sorted(used_indexes,
 308                                  GINT_TO_POINTER(pdev->acpi_index),
 309                                  g_cmp_uint32, NULL);
 310     }
 311 }
 312
 313 void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
 314                                DeviceState *dev, Error **errp)
 315 {
 316     PCIDevice *pdev = PCI_DEVICE(dev);
 317     int slot = PCI_SLOT(pdev->devfn);
 318     int bsel;
 319
 320     /* Don't send event when device is enabled during qemu machine creation:
 321      * it is present on boot, no hotplug event is necessary. We do send an
 322      * event when the device is disabled later. */
 323     if (!dev->hotplugged) {
 324         /*
 325          * Overwrite the default hotplug handler with the ACPI PCI one
 326          * for cold plugged bridges only.
 327          */
 328         if (!s->legacy_piix &&
 329             object_dynamic_cast(OBJECT(dev), TYPE_PCI_BRIDGE)) {
 330             PCIBus *sec = pci_bridge_get_sec_bus(PCI_BRIDGE(pdev));
 331
 332             qbus_set_hotplug_handler(BUS(sec), OBJECT(hotplug_dev));
 333             /* We don't have to overwrite any other hotplug handler yet */
 334             assert(QLIST_EMPTY(&sec->child));
 335         }
 336
 337         return;
 338     }
 339
 340     bsel = acpi_pcihp_get_bsel(pci_get_bus(pdev));
 341     g_assert(bsel >= 0);
 342     s->acpi_pcihp_pci_status[bsel].up |= (1U << slot);
 343     acpi_send_event(DEVICE(hotplug_dev), ACPI_PCI_HOTPLUG_STATUS);
 344 }
 345
 346 void acpi_pcihp_device_unplug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
 347                                  DeviceState *dev, Error **errp)
 348 {
 349     PCIDevice *pdev = PCI_DEVICE(dev);
 350
 351     trace_acpi_pci_unplug(PCI_SLOT(PCI_DEVICE(dev)->devfn),
 352                           acpi_pcihp_get_bsel(pci_get_bus(PCI_DEVICE(dev))));
 353
 354     /*
 355      * clean up acpi-index so it could reused by another device
 356      */
 357     if (pdev->acpi_index) {
 358         GSequence *used_indexes = pci_acpi_index_list();
 359
 360         g_sequence_remove(g_sequence_lookup(used_indexes,
 361                           GINT_TO_POINTER(pdev->acpi_index),
 362                           g_cmp_uint32, NULL));
 363     }
 364
 365     qdev_unrealize(dev);
 366 }
 367
 368 void acpi_pcihp_device_unplug_request_cb(HotplugHandler *hotplug_dev,
 369                                          AcpiPciHpState *s, DeviceState *dev,
 370                                          Error **errp)
 371 {
 372     PCIDevice *pdev = PCI_DEVICE(dev);
 373     int slot = PCI_SLOT(pdev->devfn);
 374     int bsel = acpi_pcihp_get_bsel(pci_get_bus(pdev));
 375
 376     trace_acpi_pci_unplug_request(bsel, slot);
 377
 378     if (bsel < 0) {
 379         error_setg(errp, "Unsupported bus. Bus doesn't have property '"
 380                    ACPI_PCIHP_PROP_BSEL "' set");
 381         return;
 382     }
 383
 384     s->acpi_pcihp_pci_status[bsel].down |= (1U << slot);
 385     acpi_send_event(DEVICE(hotplug_dev), ACPI_PCI_HOTPLUG_STATUS);
 386 }
 387
 388 static uint64_t pci_read(void *opaque, hwaddr addr, unsigned int size)
 389 {
 390     AcpiPciHpState *s = opaque;
 391     uint32_t val = 0;
 392     int bsel = s->hotplug_select;
 393
 394     if (bsel < 0 || bsel >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
 395         return 0;
 396     }
 397
 398     switch (addr) {
 399     case PCI_UP_BASE:
 400         val = s->acpi_pcihp_pci_status[bsel].up;
 401         if (!s->legacy_piix) {
 402             s->acpi_pcihp_pci_status[bsel].up = 0;
 403         }
 404         trace_acpi_pci_up_read(val);
 405         break;
 406     case PCI_DOWN_BASE:
 407         val = s->acpi_pcihp_pci_status[bsel].down;
 408         trace_acpi_pci_down_read(val);
 409         break;
 410     case PCI_EJ_BASE:
 411         trace_acpi_pci_features_read(val);
 412         break;
 413     case PCI_RMV_BASE:
 414         val = s->acpi_pcihp_pci_status[bsel].hotplug_enable;
 415         trace_acpi_pci_rmv_read(val);
 416         break;
 417     case PCI_SEL_BASE:
 418         val = s->hotplug_select;
 419         trace_acpi_pci_sel_read(val);
 420         break;
 421     case PCI_AIDX_BASE:
 422         val = s->acpi_index;
 423         s->acpi_index = 0;
 424         trace_acpi_pci_acpi_index_read(val);
 425         break;
 426     default:
 427         break;
 428     }
 429
 430     return val;
 431 }
 432
 433 static void pci_write(void *opaque, hwaddr addr, uint64_t data,
 434                       unsigned int size)
 435 {
 436     int slot;
 437     PCIBus *bus;
 438     BusChild *kid, *next;
 439     AcpiPciHpState *s = opaque;
 440
 441     s->acpi_index = 0;
 442     switch (addr) {
 443     case PCI_AIDX_BASE:
 444         /*
 445          * fetch acpi-index for specified slot so that follow up read from
 446          * PCI_AIDX_BASE can return it to guest
 447          */
 448         slot = ctz32(data);
 449
 450         if (s->hotplug_select >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
 451             break;
 452         }
 453
 454         bus = acpi_pcihp_find_hotplug_bus(s, s->hotplug_select);
 455         QTAILQ_FOREACH_SAFE(kid, &bus->qbus.children, sibling, next) {
 456             Object *o = OBJECT(kid->child);
 457             PCIDevice *dev = PCI_DEVICE(o);
 458             if (PCI_SLOT(dev->devfn) == slot) {
 459                 s->acpi_index = object_property_get_uint(o, "acpi-index", NULL);
 460                 break;
 461             }
 462         }
 463         trace_acpi_pci_acpi_index_write(s->hotplug_select, slot, s->acpi_index);
 464         break;
 465     case PCI_EJ_BASE:
 466         if (s->hotplug_select >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
 467             break;
 468         }
 469         acpi_pcihp_eject_slot(s, s->hotplug_select, data);
 470         trace_acpi_pci_ej_write(addr, data);
 471         break;
 472     case PCI_SEL_BASE:
 473         s->hotplug_select = s->legacy_piix ? ACPI_PCIHP_BSEL_DEFAULT : data;
 474         trace_acpi_pci_sel_write(addr, data);
 475     default:
 476         break;
 477     }
 478 }
 479
 480 static const MemoryRegionOps acpi_pcihp_io_ops = {
 481     .read = pci_read,
 482     .write = pci_write,
 483     .endianness = DEVICE_LITTLE_ENDIAN,
 484     .valid = {
 485         .min_access_size = 4,
 486         .max_access_size = 4,
 487     },
 488 };
 489
 490 void acpi_pcihp_init(Object *owner, AcpiPciHpState *s, PCIBus *root_bus,
 491                      MemoryRegion *address_space_io, bool bridges_enabled)
 492 {
 493     s->io_len = ACPI_PCIHP_SIZE;
 494     s->io_base = ACPI_PCIHP_ADDR;
 495
 496     s->root = root_bus;
 497     s->legacy_piix = !bridges_enabled;
 498
 499     memory_region_init_io(&s->io, owner, &acpi_pcihp_io_ops, s,
 500                           "acpi-pci-hotplug", s->io_len);
 501     memory_region_add_subregion(address_space_io, s->io_base, &s->io);
 502
 503     object_property_add_uint16_ptr(owner, ACPI_PCIHP_IO_BASE_PROP, &s->io_base,
 504                                    OBJ_PROP_FLAG_READ);
 505     object_property_add_uint16_ptr(owner, ACPI_PCIHP_IO_LEN_PROP, &s->io_len,
 506                                    OBJ_PROP_FLAG_READ);
 507 }
 508
 509 bool vmstate_acpi_pcihp_use_acpi_index(void *opaque, int version_id)
 510 {
 511      AcpiPciHpState *s = opaque;
 512      return s->acpi_index;
 513 }
 514
 515 const VMStateDescription vmstate_acpi_pcihp_pci_status = {
 516     .name = "acpi_pcihp_pci_status",
 517     .version_id = 1,
 518     .minimum_version_id = 1,
 519     .fields = (VMStateField[]) {
 520         VMSTATE_UINT32(up, AcpiPciHpPciStatus),
 521         VMSTATE_UINT32(down, AcpiPciHpPciStatus),
 522         VMSTATE_END_OF_LIST()
 523     }
 524 };