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