hw/virtio/virtio-mmio.c

   1 /*
   2  * Virtio MMIO bindings
   3  *
   4  * Copyright (c) 2011 Linaro Limited
   5  *
   6  * Author:
   7  *  Peter Maydell <peter.maydell@linaro.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License; either version 2
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include "qemu/osdep.h"
  23 #include "hw/sysbus.h"
  24 #include "hw/virtio/virtio.h"
  25 #include "qemu/host-utils.h"
  26 #include "sysemu/kvm.h"
  27 #include "hw/virtio/virtio-bus.h"
  28 #include "qemu/error-report.h"
  29
  30 /* #define DEBUG_VIRTIO_MMIO */
  31
  32 #ifdef DEBUG_VIRTIO_MMIO
  33
  34 #define DPRINTF(fmt, ...) \
  35 do { printf("virtio_mmio: " fmt , ## __VA_ARGS__); } while (0)
  36 #else
  37 #define DPRINTF(fmt, ...) do {} while (0)
  38 #endif
  39
  40 /* QOM macros */
  41 /* virtio-mmio-bus */
  42 #define TYPE_VIRTIO_MMIO_BUS "virtio-mmio-bus"
  43 #define VIRTIO_MMIO_BUS(obj) \
  44         OBJECT_CHECK(VirtioBusState, (obj), TYPE_VIRTIO_MMIO_BUS)
  45 #define VIRTIO_MMIO_BUS_GET_CLASS(obj) \
  46         OBJECT_GET_CLASS(VirtioBusClass, (obj), TYPE_VIRTIO_MMIO_BUS)
  47 #define VIRTIO_MMIO_BUS_CLASS(klass) \
  48         OBJECT_CLASS_CHECK(VirtioBusClass, (klass), TYPE_VIRTIO_MMIO_BUS)
  49
  50 /* virtio-mmio */
  51 #define TYPE_VIRTIO_MMIO "virtio-mmio"
  52 #define VIRTIO_MMIO(obj) \
  53         OBJECT_CHECK(VirtIOMMIOProxy, (obj), TYPE_VIRTIO_MMIO)
  54
  55 /* Memory mapped register offsets */
  56 #define VIRTIO_MMIO_MAGIC 0x0
  57 #define VIRTIO_MMIO_VERSION 0x4
  58 #define VIRTIO_MMIO_DEVICEID 0x8
  59 #define VIRTIO_MMIO_VENDORID 0xc
  60 #define VIRTIO_MMIO_HOSTFEATURES 0x10
  61 #define VIRTIO_MMIO_HOSTFEATURESSEL 0x14
  62 #define VIRTIO_MMIO_GUESTFEATURES 0x20
  63 #define VIRTIO_MMIO_GUESTFEATURESSEL 0x24
  64 #define VIRTIO_MMIO_GUESTPAGESIZE 0x28
  65 #define VIRTIO_MMIO_QUEUESEL 0x30
  66 #define VIRTIO_MMIO_QUEUENUMMAX 0x34
  67 #define VIRTIO_MMIO_QUEUENUM 0x38
  68 #define VIRTIO_MMIO_QUEUEALIGN 0x3c
  69 #define VIRTIO_MMIO_QUEUEPFN 0x40
  70 #define VIRTIO_MMIO_QUEUENOTIFY 0x50
  71 #define VIRTIO_MMIO_INTERRUPTSTATUS 0x60
  72 #define VIRTIO_MMIO_INTERRUPTACK 0x64
  73 #define VIRTIO_MMIO_STATUS 0x70
  74 /* Device specific config space starts here */
  75 #define VIRTIO_MMIO_CONFIG 0x100
  76
  77 #define VIRT_MAGIC 0x74726976 /* 'virt' */
  78 #define VIRT_VERSION 1
  79 #define VIRT_VENDOR 0x554D4551 /* 'QEMU' */
  80
  81 typedef struct {
  82     /* Generic */
  83     SysBusDevice parent_obj;
  84     MemoryRegion iomem;
  85     qemu_irq irq;
  86     /* Guest accessible state needing migration and reset */
  87     uint32_t host_features_sel;
  88     uint32_t guest_features_sel;
  89     uint32_t guest_page_shift;
  90     /* virtio-bus */
  91     VirtioBusState bus;
  92     bool format_transport_address;
  93 } VirtIOMMIOProxy;
  94
  95 static bool virtio_mmio_ioeventfd_enabled(DeviceState *d)
  96 {
  97     return kvm_eventfds_enabled();
  98 }
  99
 100 static int virtio_mmio_ioeventfd_assign(DeviceState *d,
 101                                         EventNotifier *notifier,
 102                                         int n, bool assign)
 103 {
 104     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
 105
 106     if (assign) {
 107         memory_region_add_eventfd(&proxy->iomem, VIRTIO_MMIO_QUEUENOTIFY, 4,
 108                                   true, n, notifier);
 109     } else {
 110         memory_region_del_eventfd(&proxy->iomem, VIRTIO_MMIO_QUEUENOTIFY, 4,
 111                                   true, n, notifier);
 112     }
 113     return 0;
 114 }
 115
 116 static void virtio_mmio_start_ioeventfd(VirtIOMMIOProxy *proxy)
 117 {
 118     virtio_bus_start_ioeventfd(&proxy->bus);
 119 }
 120
 121 static void virtio_mmio_stop_ioeventfd(VirtIOMMIOProxy *proxy)
 122 {
 123     virtio_bus_stop_ioeventfd(&proxy->bus);
 124 }
 125
 126 static uint64_t virtio_mmio_read(void *opaque, hwaddr offset, unsigned size)
 127 {
 128     VirtIOMMIOProxy *proxy = (VirtIOMMIOProxy *)opaque;
 129     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
 130
 131     DPRINTF("virtio_mmio_read offset 0x%x\n", (int)offset);
 132
 133     if (!vdev) {
 134         /* If no backend is present, we treat most registers as
 135          * read-as-zero, except for the magic number, version and
 136          * vendor ID. This is not strictly sanctioned by the virtio
 137          * spec, but it allows us to provide transports with no backend
 138          * plugged in which don't confuse Linux's virtio code: the
 139          * probe won't complain about the bad magic number, but the
 140          * device ID of zero means no backend will claim it.
 141          */
 142         switch (offset) {
 143         case VIRTIO_MMIO_MAGIC:
 144             return VIRT_MAGIC;
 145         case VIRTIO_MMIO_VERSION:
 146             return VIRT_VERSION;
 147         case VIRTIO_MMIO_VENDORID:
 148             return VIRT_VENDOR;
 149         default:
 150             return 0;
 151         }
 152     }
 153
 154     if (offset >= VIRTIO_MMIO_CONFIG) {
 155         offset -= VIRTIO_MMIO_CONFIG;
 156         switch (size) {
 157         case 1:
 158             return virtio_config_readb(vdev, offset);
 159         case 2:
 160             return virtio_config_readw(vdev, offset);
 161         case 4:
 162             return virtio_config_readl(vdev, offset);
 163         default:
 164             abort();
 165         }
 166     }
 167     if (size != 4) {
 168         DPRINTF("wrong size access to register!\n");
 169         return 0;
 170     }
 171     switch (offset) {
 172     case VIRTIO_MMIO_MAGIC:
 173         return VIRT_MAGIC;
 174     case VIRTIO_MMIO_VERSION:
 175         return VIRT_VERSION;
 176     case VIRTIO_MMIO_DEVICEID:
 177         return vdev->device_id;
 178     case VIRTIO_MMIO_VENDORID:
 179         return VIRT_VENDOR;
 180     case VIRTIO_MMIO_HOSTFEATURES:
 181         if (proxy->host_features_sel) {
 182             return 0;
 183         }
 184         return vdev->host_features;
 185     case VIRTIO_MMIO_QUEUENUMMAX:
 186         if (!virtio_queue_get_num(vdev, vdev->queue_sel)) {
 187             return 0;
 188         }
 189         return VIRTQUEUE_MAX_SIZE;
 190     case VIRTIO_MMIO_QUEUEPFN:
 191         return virtio_queue_get_addr(vdev, vdev->queue_sel)
 192             >> proxy->guest_page_shift;
 193     case VIRTIO_MMIO_INTERRUPTSTATUS:
 194         return atomic_read(&vdev->isr);
 195     case VIRTIO_MMIO_STATUS:
 196         return vdev->status;
 197     case VIRTIO_MMIO_HOSTFEATURESSEL:
 198     case VIRTIO_MMIO_GUESTFEATURES:
 199     case VIRTIO_MMIO_GUESTFEATURESSEL:
 200     case VIRTIO_MMIO_GUESTPAGESIZE:
 201     case VIRTIO_MMIO_QUEUESEL:
 202     case VIRTIO_MMIO_QUEUENUM:
 203     case VIRTIO_MMIO_QUEUEALIGN:
 204     case VIRTIO_MMIO_QUEUENOTIFY:
 205     case VIRTIO_MMIO_INTERRUPTACK:
 206         DPRINTF("read of write-only register\n");
 207         return 0;
 208     default:
 209         DPRINTF("bad register offset\n");
 210         return 0;
 211     }
 212     return 0;
 213 }
 214
 215 static void virtio_mmio_write(void *opaque, hwaddr offset, uint64_t value,
 216                               unsigned size)
 217 {
 218     VirtIOMMIOProxy *proxy = (VirtIOMMIOProxy *)opaque;
 219     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
 220
 221     DPRINTF("virtio_mmio_write offset 0x%x value 0x%" PRIx64 "\n",
 222             (int)offset, value);
 223
 224     if (!vdev) {
 225         /* If no backend is present, we just make all registers
 226          * write-ignored. This allows us to provide transports with
 227          * no backend plugged in.
 228          */
 229         return;
 230     }
 231
 232     if (offset >= VIRTIO_MMIO_CONFIG) {
 233         offset -= VIRTIO_MMIO_CONFIG;
 234         switch (size) {
 235         case 1:
 236             virtio_config_writeb(vdev, offset, value);
 237             break;
 238         case 2:
 239             virtio_config_writew(vdev, offset, value);
 240             break;
 241         case 4:
 242             virtio_config_writel(vdev, offset, value);
 243             break;
 244         default:
 245             abort();
 246         }
 247         return;
 248     }
 249     if (size != 4) {
 250         DPRINTF("wrong size access to register!\n");
 251         return;
 252     }
 253     switch (offset) {
 254     case VIRTIO_MMIO_HOSTFEATURESSEL:
 255         proxy->host_features_sel = value;
 256         break;
 257     case VIRTIO_MMIO_GUESTFEATURES:
 258         if (!proxy->guest_features_sel) {
 259             virtio_set_features(vdev, value);
 260         }
 261         break;
 262     case VIRTIO_MMIO_GUESTFEATURESSEL:
 263         proxy->guest_features_sel = value;
 264         break;
 265     case VIRTIO_MMIO_GUESTPAGESIZE:
 266         proxy->guest_page_shift = ctz32(value);
 267         if (proxy->guest_page_shift > 31) {
 268             proxy->guest_page_shift = 0;
 269         }
 270         DPRINTF("guest page size %" PRIx64 " shift %d\n", value,
 271                 proxy->guest_page_shift);
 272         break;
 273     case VIRTIO_MMIO_QUEUESEL:
 274         if (value < VIRTIO_QUEUE_MAX) {
 275             vdev->queue_sel = value;
 276         }
 277         break;
 278     case VIRTIO_MMIO_QUEUENUM:
 279         DPRINTF("mmio_queue write %d max %d\n", (int)value, VIRTQUEUE_MAX_SIZE);
 280         virtio_queue_set_num(vdev, vdev->queue_sel, value);
 281         /* Note: only call this function for legacy devices */
 282         virtio_queue_update_rings(vdev, vdev->queue_sel);
 283         break;
 284     case VIRTIO_MMIO_QUEUEALIGN:
 285         /* Note: this is only valid for legacy devices */
 286         virtio_queue_set_align(vdev, vdev->queue_sel, value);
 287         break;
 288     case VIRTIO_MMIO_QUEUEPFN:
 289         if (value == 0) {
 290             virtio_reset(vdev);
 291         } else {
 292             virtio_queue_set_addr(vdev, vdev->queue_sel,
 293                                   value << proxy->guest_page_shift);
 294         }
 295         break;
 296     case VIRTIO_MMIO_QUEUENOTIFY:
 297         if (value < VIRTIO_QUEUE_MAX) {
 298             virtio_queue_notify(vdev, value);
 299         }
 300         break;
 301     case VIRTIO_MMIO_INTERRUPTACK:
 302         atomic_and(&vdev->isr, ~value);
 303         virtio_update_irq(vdev);
 304         break;
 305     case VIRTIO_MMIO_STATUS:
 306         if (!(value & VIRTIO_CONFIG_S_DRIVER_OK)) {
 307             virtio_mmio_stop_ioeventfd(proxy);
 308         }
 309
 310         virtio_set_status(vdev, value & 0xff);
 311
 312         if (value & VIRTIO_CONFIG_S_DRIVER_OK) {
 313             virtio_mmio_start_ioeventfd(proxy);
 314         }
 315
 316         if (vdev->status == 0) {
 317             virtio_reset(vdev);
 318         }
 319         break;
 320     case VIRTIO_MMIO_MAGIC:
 321     case VIRTIO_MMIO_VERSION:
 322     case VIRTIO_MMIO_DEVICEID:
 323     case VIRTIO_MMIO_VENDORID:
 324     case VIRTIO_MMIO_HOSTFEATURES:
 325     case VIRTIO_MMIO_QUEUENUMMAX:
 326     case VIRTIO_MMIO_INTERRUPTSTATUS:
 327         DPRINTF("write to readonly register\n");
 328         break;
 329
 330     default:
 331         DPRINTF("bad register offset\n");
 332     }
 333 }
 334
 335 static const MemoryRegionOps virtio_mem_ops = {
 336     .read = virtio_mmio_read,
 337     .write = virtio_mmio_write,
 338     .endianness = DEVICE_NATIVE_ENDIAN,
 339 };
 340
 341 static void virtio_mmio_update_irq(DeviceState *opaque, uint16_t vector)
 342 {
 343     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
 344     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
 345     int level;
 346
 347     if (!vdev) {
 348         return;
 349     }
 350     level = (atomic_read(&vdev->isr) != 0);
 351     DPRINTF("virtio_mmio setting IRQ %d\n", level);
 352     qemu_set_irq(proxy->irq, level);
 353 }
 354
 355 static int virtio_mmio_load_config(DeviceState *opaque, QEMUFile *f)
 356 {
 357     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
 358
 359     proxy->host_features_sel = qemu_get_be32(f);
 360     proxy->guest_features_sel = qemu_get_be32(f);
 361     proxy->guest_page_shift = qemu_get_be32(f);
 362     return 0;
 363 }
 364
 365 static void virtio_mmio_save_config(DeviceState *opaque, QEMUFile *f)
 366 {
 367     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
 368
 369     qemu_put_be32(f, proxy->host_features_sel);
 370     qemu_put_be32(f, proxy->guest_features_sel);
 371     qemu_put_be32(f, proxy->guest_page_shift);
 372 }
 373
 374 static void virtio_mmio_reset(DeviceState *d)
 375 {
 376     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
 377
 378     virtio_mmio_stop_ioeventfd(proxy);
 379     virtio_bus_reset(&proxy->bus);
 380     proxy->host_features_sel = 0;
 381     proxy->guest_features_sel = 0;
 382     proxy->guest_page_shift = 0;
 383 }
 384
 385 static int virtio_mmio_set_guest_notifier(DeviceState *d, int n, bool assign,
 386                                           bool with_irqfd)
 387 {
 388     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
 389     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
 390     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
 391     VirtQueue *vq = virtio_get_queue(vdev, n);
 392     EventNotifier *notifier = virtio_queue_get_guest_notifier(vq);
 393
 394     if (assign) {
 395         int r = event_notifier_init(notifier, 0);
 396         if (r < 0) {
 397             return r;
 398         }
 399         virtio_queue_set_guest_notifier_fd_handler(vq, true, with_irqfd);
 400     } else {
 401         virtio_queue_set_guest_notifier_fd_handler(vq, false, with_irqfd);
 402         event_notifier_cleanup(notifier);
 403     }
 404
 405     if (vdc->guest_notifier_mask && vdev->use_guest_notifier_mask) {
 406         vdc->guest_notifier_mask(vdev, n, !assign);
 407     }
 408
 409     return 0;
 410 }
 411
 412 static int virtio_mmio_set_guest_notifiers(DeviceState *d, int nvqs,
 413                                            bool assign)
 414 {
 415     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
 416     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
 417     /* TODO: need to check if kvm-arm supports irqfd */
 418     bool with_irqfd = false;
 419     int r, n;
 420
 421     nvqs = MIN(nvqs, VIRTIO_QUEUE_MAX);
 422
 423     for (n = 0; n < nvqs; n++) {
 424         if (!virtio_queue_get_num(vdev, n)) {
 425             break;
 426         }
 427
 428         r = virtio_mmio_set_guest_notifier(d, n, assign, with_irqfd);
 429         if (r < 0) {
 430             goto assign_error;
 431         }
 432     }
 433
 434     return 0;
 435
 436 assign_error:
 437     /* We get here on assignment failure. Recover by undoing for VQs 0 .. n. */
 438     assert(assign);
 439     while (--n >= 0) {
 440         virtio_mmio_set_guest_notifier(d, n, !assign, false);
 441     }
 442     return r;
 443 }
 444
 445 /* virtio-mmio device */
 446
 447 static Property virtio_mmio_properties[] = {
 448     DEFINE_PROP_BOOL("format_transport_address", VirtIOMMIOProxy,
 449                      format_transport_address, true),
 450     DEFINE_PROP_END_OF_LIST(),
 451 };
 452
 453 static void virtio_mmio_realizefn(DeviceState *d, Error **errp)
 454 {
 455     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
 456     SysBusDevice *sbd = SYS_BUS_DEVICE(d);
 457
 458     qbus_create_inplace(&proxy->bus, sizeof(proxy->bus), TYPE_VIRTIO_MMIO_BUS,
 459                         d, NULL);
 460     sysbus_init_irq(sbd, &proxy->irq);
 461     memory_region_init_io(&proxy->iomem, OBJECT(d), &virtio_mem_ops, proxy,
 462                           TYPE_VIRTIO_MMIO, 0x200);
 463     sysbus_init_mmio(sbd, &proxy->iomem);
 464 }
 465
 466 static void virtio_mmio_class_init(ObjectClass *klass, void *data)
 467 {
 468     DeviceClass *dc = DEVICE_CLASS(klass);
 469
 470     dc->realize = virtio_mmio_realizefn;
 471     dc->reset = virtio_mmio_reset;
 472     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 473     dc->props = virtio_mmio_properties;
 474 }
 475
 476 static const TypeInfo virtio_mmio_info = {
 477     .name          = TYPE_VIRTIO_MMIO,
 478     .parent        = TYPE_SYS_BUS_DEVICE,
 479     .instance_size = sizeof(VirtIOMMIOProxy),
 480     .class_init    = virtio_mmio_class_init,
 481 };
 482
 483 /* virtio-mmio-bus. */
 484
 485 static char *virtio_mmio_bus_get_dev_path(DeviceState *dev)
 486 {
 487     BusState *virtio_mmio_bus;
 488     VirtIOMMIOProxy *virtio_mmio_proxy;
 489     char *proxy_path;
 490     SysBusDevice *proxy_sbd;
 491     char *path;
 492
 493     virtio_mmio_bus = qdev_get_parent_bus(dev);
 494     virtio_mmio_proxy = VIRTIO_MMIO(virtio_mmio_bus->parent);
 495     proxy_path = qdev_get_dev_path(DEVICE(virtio_mmio_proxy));
 496
 497     /*
 498      * If @format_transport_address is false, then we just perform the same as
 499      * virtio_bus_get_dev_path(): we delegate the address formatting for the
 500      * device on the virtio-mmio bus to the bus that the virtio-mmio proxy
 501      * (i.e., the device that implements the virtio-mmio bus) resides on. In
 502      * this case the base address of the virtio-mmio transport will be
 503      * invisible.
 504      */
 505     if (!virtio_mmio_proxy->format_transport_address) {
 506         return proxy_path;
 507     }
 508
 509     /* Otherwise, we append the base address of the transport. */
 510     proxy_sbd = SYS_BUS_DEVICE(virtio_mmio_proxy);
 511     assert(proxy_sbd->num_mmio == 1);
 512     assert(proxy_sbd->mmio[0].memory == &virtio_mmio_proxy->iomem);
 513
 514     if (proxy_path) {
 515         path = g_strdup_printf("%s/virtio-mmio@" TARGET_FMT_plx, proxy_path,
 516                                proxy_sbd->mmio[0].addr);
 517     } else {
 518         path = g_strdup_printf("virtio-mmio@" TARGET_FMT_plx,
 519                                proxy_sbd->mmio[0].addr);
 520     }
 521     g_free(proxy_path);
 522     return path;
 523 }
 524
 525 static void virtio_mmio_bus_class_init(ObjectClass *klass, void *data)
 526 {
 527     BusClass *bus_class = BUS_CLASS(klass);
 528     VirtioBusClass *k = VIRTIO_BUS_CLASS(klass);
 529
 530     k->notify = virtio_mmio_update_irq;
 531     k->save_config = virtio_mmio_save_config;
 532     k->load_config = virtio_mmio_load_config;
 533     k->set_guest_notifiers = virtio_mmio_set_guest_notifiers;
 534     k->ioeventfd_enabled = virtio_mmio_ioeventfd_enabled;
 535     k->ioeventfd_assign = virtio_mmio_ioeventfd_assign;
 536     k->has_variable_vring_alignment = true;
 537     bus_class->max_dev = 1;
 538     bus_class->get_dev_path = virtio_mmio_bus_get_dev_path;
 539 }
 540
 541 static const TypeInfo virtio_mmio_bus_info = {
 542     .name          = TYPE_VIRTIO_MMIO_BUS,
 543     .parent        = TYPE_VIRTIO_BUS,
 544     .instance_size = sizeof(VirtioBusState),
 545     .class_init    = virtio_mmio_bus_class_init,
 546 };
 547
 548 static void virtio_mmio_register_types(void)
 549 {
 550     type_register_static(&virtio_mmio_bus_info);
 551     type_register_static(&virtio_mmio_info);
 552 }
 553
 554 type_init(virtio_mmio_register_types)