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 "exec/address-spaces.h"
  35 #include "hw/pci/pci_bus.h"
  36 #include "migration/vmstate.h"
  37 #include "qapi/error.h"
  38 #include "qom/qom-qobject.h"
  39 #include "trace.h"
  40
  41 #define ACPI_PCIHP_ADDR 0xae00
  42 #define ACPI_PCIHP_SIZE 0x0018
  43 #define PCI_UP_BASE 0x0000
  44 #define PCI_DOWN_BASE 0x0004
  45 #define PCI_EJ_BASE 0x0008
  46 #define PCI_RMV_BASE 0x000c
  47 #define PCI_SEL_BASE 0x0010
  48 #define PCI_AIDX_BASE 0x0014
  49
  50 typedef struct AcpiPciHpFind {
  51     int bsel;
  52     PCIBus *bus;
  53 } AcpiPciHpFind;
  54
  55 static gint g_cmp_uint32(gconstpointer a, gconstpointer b, gpointer user_data)
  56 {
  57     return a - b;
  58 }
  59
  60 static GSequence *pci_acpi_index_list(void)
  61 {
  62     static GSequence *used_acpi_index_list;
  63
  64     if (!used_acpi_index_list) {
  65         used_acpi_index_list = g_sequence_new(NULL);
  66     }
  67     return used_acpi_index_list;
  68 }
  69
  70 static int acpi_pcihp_get_bsel(PCIBus *bus)
  71 {
  72     Error *local_err = NULL;
  73     uint64_t bsel = object_property_get_uint(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
  74                                              &local_err);
  75
  76     if (local_err || bsel >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
  77         if (local_err) {
  78             error_free(local_err);
  79         }
  80         return -1;
  81     } else {
  82         return bsel;
  83     }
  84 }
  85
  86 /* Assign BSEL property to all buses.  In the future, this can be changed
  87  * to only assign to buses that support hotplug.
  88  */
  89 static void *acpi_set_bsel(PCIBus *bus, void *opaque)
  90 {
  91     unsigned *bsel_alloc = opaque;
  92     unsigned *bus_bsel;
  93
  94     if (qbus_is_hotpluggable(BUS(bus))) {
  95         bus_bsel = g_malloc(sizeof *bus_bsel);
  96
  97         *bus_bsel = (*bsel_alloc)++;
  98         object_property_add_uint32_ptr(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
  99                                        bus_bsel, OBJ_PROP_FLAG_READ);
 100     }
 101
 102     return bsel_alloc;
 103 }
 104
 105 static void acpi_set_pci_info(void)
 106 {
 107     static bool bsel_is_set;
 108     PCIBus *bus;
 109     unsigned bsel_alloc = ACPI_PCIHP_BSEL_DEFAULT;
 110
 111     if (bsel_is_set) {
 112         return;
 113     }
 114     bsel_is_set = true;
 115
 116     bus = find_i440fx(); /* TODO: Q35 support */
 117     if (bus) {
 118         /* Scan all PCI buses. Set property to enable acpi based hotplug. */
 119         pci_for_each_bus_depth_first(bus, acpi_set_bsel, NULL, &bsel_alloc);
 120     }
 121 }
 122
 123 static void acpi_pcihp_disable_root_bus(void)
 124 {
 125     static bool root_hp_disabled;
 126     PCIBus *bus;
 127
 128     if (root_hp_disabled) {
 129         return;
 130     }
 131
 132     bus = find_i440fx();
 133     if (bus) {
 134         /* setting the hotplug handler to NULL makes the bus non-hotpluggable */
 135         qbus_set_hotplug_handler(BUS(bus), NULL);
 136     }
 137     root_hp_disabled = true;
 138     return;
 139 }
 140
 141 static void acpi_pcihp_test_hotplug_bus(PCIBus *bus, void *opaque)
 142 {
 143     AcpiPciHpFind *find = opaque;
 144     if (find->bsel == acpi_pcihp_get_bsel(bus)) {
 145         find->bus = bus;
 146     }
 147 }
 148
 149 static PCIBus *acpi_pcihp_find_hotplug_bus(AcpiPciHpState *s, int bsel)
 150 {
 151     AcpiPciHpFind find = { .bsel = bsel, .bus = NULL };
 152
 153     if (bsel < 0) {
 154         return NULL;
 155     }
 156
 157     pci_for_each_bus(s->root, acpi_pcihp_test_hotplug_bus, &find);
 158
 159     /* Make bsel 0 eject root bus if bsel property is not set,
 160      * for compatibility with non acpi setups.
 161      * TODO: really needed?
 162      */
 163     if (!bsel && !find.bus) {
 164         find.bus = s->root;
 165     }
 166
 167     /*
 168      * Check if find.bus is actually hotpluggable. If bsel is set to
 169      * NULL for example on the root bus in order to make it
 170      * non-hotpluggable, find.bus will match the root bus when bsel
 171      * is 0. See acpi_pcihp_test_hotplug_bus() above. Since the
 172      * bus is not hotpluggable however, we should not select the bus.
 173      * Instead, we should set find.bus to NULL in that case. In the check
 174      * below, we generalize this case for all buses, not just the root bus.
 175      * The callers of this function check for a null return value and
 176      * handle them appropriately.
 177      */
 178     if (find.bus && !qbus_is_hotpluggable(BUS(find.bus))) {
 179         find.bus = NULL;
 180     }
 181     return find.bus;
 182 }
 183
 184 static bool acpi_pcihp_pc_no_hotplug(AcpiPciHpState *s, PCIDevice *dev)
 185 {
 186     PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(dev);
 187     DeviceClass *dc = DEVICE_GET_CLASS(dev);
 188     /*
 189      * ACPI doesn't allow hotplug of bridge devices.  Don't allow
 190      * hot-unplug of bridge devices unless they were added by hotplug
 191      * (and so, not described by acpi).
 192      */
 193     return (pc->is_bridge && !dev->qdev.hotplugged) || !dc->hotpluggable;
 194 }
 195
 196 static void acpi_pcihp_eject_slot(AcpiPciHpState *s, unsigned bsel, unsigned slots)
 197 {
 198     HotplugHandler *hotplug_ctrl;
 199     BusChild *kid, *next;
 200     int slot = ctz32(slots);
 201     PCIBus *bus = acpi_pcihp_find_hotplug_bus(s, bsel);
 202
 203     trace_acpi_pci_eject_slot(bsel, slot);
 204
 205     if (!bus || slot > 31) {
 206         return;
 207     }
 208
 209     /* Mark request as complete */
 210     s->acpi_pcihp_pci_status[bsel].down &= ~(1U << slot);
 211     s->acpi_pcihp_pci_status[bsel].up &= ~(1U << slot);
 212
 213     QTAILQ_FOREACH_SAFE(kid, &bus->qbus.children, sibling, next) {
 214         DeviceState *qdev = kid->child;
 215         PCIDevice *dev = PCI_DEVICE(qdev);
 216         if (PCI_SLOT(dev->devfn) == slot) {
 217             if (!acpi_pcihp_pc_no_hotplug(s, dev)) {
 218                 hotplug_ctrl = qdev_get_hotplug_handler(qdev);
 219                 hotplug_handler_unplug(hotplug_ctrl, qdev, &error_abort);
 220                 object_unparent(OBJECT(qdev));
 221             }
 222         }
 223     }
 224 }
 225
 226 static void acpi_pcihp_update_hotplug_bus(AcpiPciHpState *s, int bsel)
 227 {
 228     BusChild *kid, *next;
 229     PCIBus *bus = acpi_pcihp_find_hotplug_bus(s, bsel);
 230
 231     /* Execute any pending removes during reset */
 232     while (s->acpi_pcihp_pci_status[bsel].down) {
 233         acpi_pcihp_eject_slot(s, bsel, s->acpi_pcihp_pci_status[bsel].down);
 234     }
 235
 236     s->acpi_pcihp_pci_status[bsel].hotplug_enable = ~0;
 237
 238     if (!bus) {
 239         return;
 240     }
 241     QTAILQ_FOREACH_SAFE(kid, &bus->qbus.children, sibling, next) {
 242         DeviceState *qdev = kid->child;
 243         PCIDevice *pdev = PCI_DEVICE(qdev);
 244         int slot = PCI_SLOT(pdev->devfn);
 245
 246         if (acpi_pcihp_pc_no_hotplug(s, pdev)) {
 247             s->acpi_pcihp_pci_status[bsel].hotplug_enable &= ~(1U << slot);
 248         }
 249     }
 250 }
 251
 252 static void acpi_pcihp_update(AcpiPciHpState *s)
 253 {
 254     int i;
 255
 256     for (i = 0; i < ACPI_PCIHP_MAX_HOTPLUG_BUS; ++i) {
 257         acpi_pcihp_update_hotplug_bus(s, i);
 258     }
 259 }
 260
 261 void acpi_pcihp_reset(AcpiPciHpState *s, bool acpihp_root_off)
 262 {
 263     if (acpihp_root_off) {
 264         acpi_pcihp_disable_root_bus();
 265     }
 266     acpi_set_pci_info();
 267     acpi_pcihp_update(s);
 268 }
 269
 270 #define ONBOARD_INDEX_MAX (16 * 1024 - 1)
 271
 272 void acpi_pcihp_device_pre_plug_cb(HotplugHandler *hotplug_dev,
 273                                    DeviceState *dev, Error **errp)
 274 {
 275     PCIDevice *pdev = PCI_DEVICE(dev);
 276
 277     /* Only hotplugged devices need the hotplug capability. */
 278     if (dev->hotplugged &&
 279         acpi_pcihp_get_bsel(pci_get_bus(PCI_DEVICE(dev))) < 0) {
 280         error_setg(errp, "Unsupported bus. Bus doesn't have property '"
 281                    ACPI_PCIHP_PROP_BSEL "' set");
 282         return;
 283     }
 284
 285     /*
 286      * capped by systemd (see: udev-builtin-net_id.c)
 287      * as it's the only known user honor it to avoid users
 288      * misconfigure QEMU and then wonder why acpi-index doesn't work
 289      */
 290     if (pdev->acpi_index > ONBOARD_INDEX_MAX) {
 291         error_setg(errp, "acpi-index should be less or equal to %u",
 292                    ONBOARD_INDEX_MAX);
 293         return;
 294     }
 295
 296     /*
 297      * make sure that acpi-index is unique across all present PCI devices
 298      */
 299     if (pdev->acpi_index) {
 300         GSequence *used_indexes = pci_acpi_index_list();
 301
 302         if (g_sequence_lookup(used_indexes, GINT_TO_POINTER(pdev->acpi_index),
 303                               g_cmp_uint32, NULL)) {
 304             error_setg(errp, "a PCI device with acpi-index = %" PRIu32
 305                        " already exist", pdev->acpi_index);
 306             return;
 307         }
 308         g_sequence_insert_sorted(used_indexes,
 309                                  GINT_TO_POINTER(pdev->acpi_index),
 310                                  g_cmp_uint32, NULL);
 311     }
 312 }
 313
 314 void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
 315                                DeviceState *dev, Error **errp)
 316 {
 317     PCIDevice *pdev = PCI_DEVICE(dev);
 318     int slot = PCI_SLOT(pdev->devfn);
 319     int bsel;
 320
 321     /* Don't send event when device is enabled during qemu machine creation:
 322      * it is present on boot, no hotplug event is necessary. We do send an
 323      * event when the device is disabled later. */
 324     if (!dev->hotplugged) {
 325         /*
 326          * Overwrite the default hotplug handler with the ACPI PCI one
 327          * for cold plugged bridges only.
 328          */
 329         if (!s->legacy_piix &&
 330             object_dynamic_cast(OBJECT(dev), TYPE_PCI_BRIDGE)) {
 331             PCIBus *sec = pci_bridge_get_sec_bus(PCI_BRIDGE(pdev));
 332
 333             qbus_set_hotplug_handler(BUS(sec), OBJECT(hotplug_dev));
 334             /* We don't have to overwrite any other hotplug handler yet */
 335             assert(QLIST_EMPTY(&sec->child));
 336         }
 337
 338         return;
 339     }
 340
 341     bsel = acpi_pcihp_get_bsel(pci_get_bus(pdev));
 342     g_assert(bsel >= 0);
 343     s->acpi_pcihp_pci_status[bsel].up |= (1U << slot);
 344     acpi_send_event(DEVICE(hotplug_dev), ACPI_PCI_HOTPLUG_STATUS);
 345 }
 346
 347 void acpi_pcihp_device_unplug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
 348                                  DeviceState *dev, Error **errp)
 349 {
 350     PCIDevice *pdev = PCI_DEVICE(dev);
 351
 352     trace_acpi_pci_unplug(PCI_SLOT(PCI_DEVICE(dev)->devfn),
 353                           acpi_pcihp_get_bsel(pci_get_bus(PCI_DEVICE(dev))));
 354
 355     /*
 356      * clean up acpi-index so it could reused by another device
 357      */
 358     if (pdev->acpi_index) {
 359         GSequence *used_indexes = pci_acpi_index_list();
 360
 361         g_sequence_remove(g_sequence_lookup(used_indexes,
 362                           GINT_TO_POINTER(pdev->acpi_index),
 363                           g_cmp_uint32, NULL));
 364     }
 365
 366     qdev_unrealize(dev);
 367 }
 368
 369 void acpi_pcihp_device_unplug_request_cb(HotplugHandler *hotplug_dev,
 370                                          AcpiPciHpState *s, DeviceState *dev,
 371                                          Error **errp)
 372 {
 373     PCIDevice *pdev = PCI_DEVICE(dev);
 374     int slot = PCI_SLOT(pdev->devfn);
 375     int bsel = acpi_pcihp_get_bsel(pci_get_bus(pdev));
 376
 377     trace_acpi_pci_unplug_request(bsel, slot);
 378
 379     if (bsel < 0) {
 380         error_setg(errp, "Unsupported bus. Bus doesn't have property '"
 381                    ACPI_PCIHP_PROP_BSEL "' set");
 382         return;
 383     }
 384
 385     s->acpi_pcihp_pci_status[bsel].down |= (1U << slot);
 386     acpi_send_event(DEVICE(hotplug_dev), ACPI_PCI_HOTPLUG_STATUS);
 387 }
 388
 389 static uint64_t pci_read(void *opaque, hwaddr addr, unsigned int size)
 390 {
 391     AcpiPciHpState *s = opaque;
 392     uint32_t val = 0;
 393     int bsel = s->hotplug_select;
 394
 395     if (bsel < 0 || bsel >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
 396         return 0;
 397     }
 398
 399     switch (addr) {
 400     case PCI_UP_BASE:
 401         val = s->acpi_pcihp_pci_status[bsel].up;
 402         if (!s->legacy_piix) {
 403             s->acpi_pcihp_pci_status[bsel].up = 0;
 404         }
 405         trace_acpi_pci_up_read(val);
 406         break;
 407     case PCI_DOWN_BASE:
 408         val = s->acpi_pcihp_pci_status[bsel].down;
 409         trace_acpi_pci_down_read(val);
 410         break;
 411     case PCI_EJ_BASE:
 412         trace_acpi_pci_features_read(val);
 413         break;
 414     case PCI_RMV_BASE:
 415         val = s->acpi_pcihp_pci_status[bsel].hotplug_enable;
 416         trace_acpi_pci_rmv_read(val);
 417         break;
 418     case PCI_SEL_BASE:
 419         val = s->hotplug_select;
 420         trace_acpi_pci_sel_read(val);
 421         break;
 422     case PCI_AIDX_BASE:
 423         val = s->acpi_index;
 424         s->acpi_index = 0;
 425         trace_acpi_pci_acpi_index_read(val);
 426         break;
 427     default:
 428         break;
 429     }
 430
 431     return val;
 432 }
 433
 434 static void pci_write(void *opaque, hwaddr addr, uint64_t data,
 435                       unsigned int size)
 436 {
 437     int slot;
 438     PCIBus *bus;
 439     BusChild *kid, *next;
 440     AcpiPciHpState *s = opaque;
 441
 442     s->acpi_index = 0;
 443     switch (addr) {
 444     case PCI_AIDX_BASE:
 445         /*
 446          * fetch acpi-index for specified slot so that follow up read from
 447          * PCI_AIDX_BASE can return it to guest
 448          */
 449         slot = ctz32(data);
 450
 451         if (s->hotplug_select >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
 452             break;
 453         }
 454
 455         bus = acpi_pcihp_find_hotplug_bus(s, s->hotplug_select);
 456         QTAILQ_FOREACH_SAFE(kid, &bus->qbus.children, sibling, next) {
 457             Object *o = OBJECT(kid->child);
 458             PCIDevice *dev = PCI_DEVICE(o);
 459             if (PCI_SLOT(dev->devfn) == slot) {
 460                 s->acpi_index = object_property_get_uint(o, "acpi-index", NULL);
 461                 break;
 462             }
 463         }
 464         trace_acpi_pci_acpi_index_write(s->hotplug_select, slot, s->acpi_index);
 465         break;
 466     case PCI_EJ_BASE:
 467         if (s->hotplug_select >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
 468             break;
 469         }
 470         acpi_pcihp_eject_slot(s, s->hotplug_select, data);
 471         trace_acpi_pci_ej_write(addr, data);
 472         break;
 473     case PCI_SEL_BASE:
 474         s->hotplug_select = s->legacy_piix ? ACPI_PCIHP_BSEL_DEFAULT : data;
 475         trace_acpi_pci_sel_write(addr, data);
 476     default:
 477         break;
 478     }
 479 }
 480
 481 static const MemoryRegionOps acpi_pcihp_io_ops = {
 482     .read = pci_read,
 483     .write = pci_write,
 484     .endianness = DEVICE_LITTLE_ENDIAN,
 485     .valid = {
 486         .min_access_size = 4,
 487         .max_access_size = 4,
 488     },
 489 };
 490
 491 void acpi_pcihp_init(Object *owner, AcpiPciHpState *s, PCIBus *root_bus,
 492                      MemoryRegion *address_space_io, bool bridges_enabled)
 493 {
 494     s->io_len = ACPI_PCIHP_SIZE;
 495     s->io_base = ACPI_PCIHP_ADDR;
 496
 497     s->root = root_bus;
 498     s->legacy_piix = !bridges_enabled;
 499
 500     memory_region_init_io(&s->io, owner, &acpi_pcihp_io_ops, s,
 501                           "acpi-pci-hotplug", s->io_len);
 502     memory_region_add_subregion(address_space_io, s->io_base, &s->io);
 503
 504     object_property_add_uint16_ptr(owner, ACPI_PCIHP_IO_BASE_PROP, &s->io_base,
 505                                    OBJ_PROP_FLAG_READ);
 506     object_property_add_uint16_ptr(owner, ACPI_PCIHP_IO_LEN_PROP, &s->io_len,
 507                                    OBJ_PROP_FLAG_READ);
 508 }
 509
 510 bool vmstate_acpi_pcihp_use_acpi_index(void *opaque, int version_id)
 511 {
 512      AcpiPciHpState *s = opaque;
 513      return s->acpi_index;
 514 }
 515
 516 const VMStateDescription vmstate_acpi_pcihp_pci_status = {
 517     .name = "acpi_pcihp_pci_status",
 518     .version_id = 1,
 519     .minimum_version_id = 1,
 520     .fields = (VMStateField[]) {
 521         VMSTATE_UINT32(up, AcpiPciHpPciStatus),
 522         VMSTATE_UINT32(down, AcpiPciHpPciStatus),
 523         VMSTATE_END_OF_LIST()
 524     }
 525 };