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 "hw/sysbus.h"
  23 #include "hw/virtio/virtio.h"
  24 #include "qemu/host-utils.h"
  25 #include "hw/virtio/virtio-bus.h"
  26
  27 /* #define DEBUG_VIRTIO_MMIO */
  28
  29 #ifdef DEBUG_VIRTIO_MMIO
  30
  31 #define DPRINTF(fmt, ...) \
  32 do { printf("virtio_mmio: " fmt , ## __VA_ARGS__); } while (0)
  33 #else
  34 #define DPRINTF(fmt, ...) do {} while (0)
  35 #endif
  36
  37 /* QOM macros */
  38 /* virtio-mmio-bus */
  39 #define TYPE_VIRTIO_MMIO_BUS "virtio-mmio-bus"
  40 #define VIRTIO_MMIO_BUS(obj) \
  41         OBJECT_CHECK(VirtioBusState, (obj), TYPE_VIRTIO_MMIO_BUS)
  42 #define VIRTIO_MMIO_BUS_GET_CLASS(obj) \
  43         OBJECT_GET_CLASS(VirtioBusClass, (obj), TYPE_VIRTIO_MMIO_BUS)
  44 #define VIRTIO_MMIO_BUS_CLASS(klass) \
  45         OBJECT_CLASS_CHECK(VirtioBusClass, (klass), TYPE_VIRTIO_MMIO_BUS)
  46
  47 /* virtio-mmio */
  48 #define TYPE_VIRTIO_MMIO "virtio-mmio"
  49 #define VIRTIO_MMIO(obj) \
  50         OBJECT_CHECK(VirtIOMMIOProxy, (obj), TYPE_VIRTIO_MMIO)
  51
  52 /* Memory mapped register offsets */
  53 #define VIRTIO_MMIO_MAGIC 0x0
  54 #define VIRTIO_MMIO_VERSION 0x4
  55 #define VIRTIO_MMIO_DEVICEID 0x8
  56 #define VIRTIO_MMIO_VENDORID 0xc
  57 #define VIRTIO_MMIO_HOSTFEATURES 0x10
  58 #define VIRTIO_MMIO_HOSTFEATURESSEL 0x14
  59 #define VIRTIO_MMIO_GUESTFEATURES 0x20
  60 #define VIRTIO_MMIO_GUESTFEATURESSEL 0x24
  61 #define VIRTIO_MMIO_GUESTPAGESIZE 0x28
  62 #define VIRTIO_MMIO_QUEUESEL 0x30
  63 #define VIRTIO_MMIO_QUEUENUMMAX 0x34
  64 #define VIRTIO_MMIO_QUEUENUM 0x38
  65 #define VIRTIO_MMIO_QUEUEALIGN 0x3c
  66 #define VIRTIO_MMIO_QUEUEPFN 0x40
  67 #define VIRTIO_MMIO_QUEUENOTIFY 0x50
  68 #define VIRTIO_MMIO_INTERRUPTSTATUS 0x60
  69 #define VIRTIO_MMIO_INTERRUPTACK 0x64
  70 #define VIRTIO_MMIO_STATUS 0x70
  71 /* Device specific config space starts here */
  72 #define VIRTIO_MMIO_CONFIG 0x100
  73
  74 #define VIRT_MAGIC 0x74726976 /* 'virt' */
  75 #define VIRT_VERSION 1
  76 #define VIRT_VENDOR 0x554D4551 /* 'QEMU' */
  77
  78 typedef struct {
  79     /* Generic */
  80     SysBusDevice parent_obj;
  81     MemoryRegion iomem;
  82     qemu_irq irq;
  83     /* Guest accessible state needing migration and reset */
  84     uint32_t host_features_sel;
  85     uint32_t guest_features_sel;
  86     uint32_t guest_page_shift;
  87     /* virtio-bus */
  88     VirtioBusState bus;
  89 } VirtIOMMIOProxy;
  90
  91 static uint64_t virtio_mmio_read(void *opaque, hwaddr offset, unsigned size)
  92 {
  93     VirtIOMMIOProxy *proxy = (VirtIOMMIOProxy *)opaque;
  94     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
  95
  96     DPRINTF("virtio_mmio_read offset 0x%x\n", (int)offset);
  97
  98     if (!vdev) {
  99         /* If no backend is present, we treat most registers as
 100          * read-as-zero, except for the magic number, version and
 101          * vendor ID. This is not strictly sanctioned by the virtio
 102          * spec, but it allows us to provide transports with no backend
 103          * plugged in which don't confuse Linux's virtio code: the
 104          * probe won't complain about the bad magic number, but the
 105          * device ID of zero means no backend will claim it.
 106          */
 107         switch (offset) {
 108         case VIRTIO_MMIO_MAGIC:
 109             return VIRT_MAGIC;
 110         case VIRTIO_MMIO_VERSION:
 111             return VIRT_VERSION;
 112         case VIRTIO_MMIO_VENDORID:
 113             return VIRT_VENDOR;
 114         default:
 115             return 0;
 116         }
 117     }
 118
 119     if (offset >= VIRTIO_MMIO_CONFIG) {
 120         offset -= VIRTIO_MMIO_CONFIG;
 121         switch (size) {
 122         case 1:
 123             return virtio_config_readb(vdev, offset);
 124         case 2:
 125             return virtio_config_readw(vdev, offset);
 126         case 4:
 127             return virtio_config_readl(vdev, offset);
 128         default:
 129             abort();
 130         }
 131     }
 132     if (size != 4) {
 133         DPRINTF("wrong size access to register!\n");
 134         return 0;
 135     }
 136     switch (offset) {
 137     case VIRTIO_MMIO_MAGIC:
 138         return VIRT_MAGIC;
 139     case VIRTIO_MMIO_VERSION:
 140         return VIRT_VERSION;
 141     case VIRTIO_MMIO_DEVICEID:
 142         return vdev->device_id;
 143     case VIRTIO_MMIO_VENDORID:
 144         return VIRT_VENDOR;
 145     case VIRTIO_MMIO_HOSTFEATURES:
 146         if (proxy->host_features_sel) {
 147             return 0;
 148         }
 149         return vdev->host_features;
 150     case VIRTIO_MMIO_QUEUENUMMAX:
 151         if (!virtio_queue_get_num(vdev, vdev->queue_sel)) {
 152             return 0;
 153         }
 154         return VIRTQUEUE_MAX_SIZE;
 155     case VIRTIO_MMIO_QUEUEPFN:
 156         return virtio_queue_get_addr(vdev, vdev->queue_sel)
 157             >> proxy->guest_page_shift;
 158     case VIRTIO_MMIO_INTERRUPTSTATUS:
 159         return vdev->isr;
 160     case VIRTIO_MMIO_STATUS:
 161         return vdev->status;
 162     case VIRTIO_MMIO_HOSTFEATURESSEL:
 163     case VIRTIO_MMIO_GUESTFEATURES:
 164     case VIRTIO_MMIO_GUESTFEATURESSEL:
 165     case VIRTIO_MMIO_GUESTPAGESIZE:
 166     case VIRTIO_MMIO_QUEUESEL:
 167     case VIRTIO_MMIO_QUEUENUM:
 168     case VIRTIO_MMIO_QUEUEALIGN:
 169     case VIRTIO_MMIO_QUEUENOTIFY:
 170     case VIRTIO_MMIO_INTERRUPTACK:
 171         DPRINTF("read of write-only register\n");
 172         return 0;
 173     default:
 174         DPRINTF("bad register offset\n");
 175         return 0;
 176     }
 177     return 0;
 178 }
 179
 180 static void virtio_mmio_write(void *opaque, hwaddr offset, uint64_t value,
 181                               unsigned size)
 182 {
 183     VirtIOMMIOProxy *proxy = (VirtIOMMIOProxy *)opaque;
 184     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
 185
 186     DPRINTF("virtio_mmio_write offset 0x%x value 0x%" PRIx64 "\n",
 187             (int)offset, value);
 188
 189     if (!vdev) {
 190         /* If no backend is present, we just make all registers
 191          * write-ignored. This allows us to provide transports with
 192          * no backend plugged in.
 193          */
 194         return;
 195     }
 196
 197     if (offset >= VIRTIO_MMIO_CONFIG) {
 198         offset -= VIRTIO_MMIO_CONFIG;
 199         switch (size) {
 200         case 1:
 201             virtio_config_writeb(vdev, offset, value);
 202             break;
 203         case 2:
 204             virtio_config_writew(vdev, offset, value);
 205             break;
 206         case 4:
 207             virtio_config_writel(vdev, offset, value);
 208             break;
 209         default:
 210             abort();
 211         }
 212         return;
 213     }
 214     if (size != 4) {
 215         DPRINTF("wrong size access to register!\n");
 216         return;
 217     }
 218     switch (offset) {
 219     case VIRTIO_MMIO_HOSTFEATURESSEL:
 220         proxy->host_features_sel = value;
 221         break;
 222     case VIRTIO_MMIO_GUESTFEATURES:
 223         if (!proxy->guest_features_sel) {
 224             virtio_set_features(vdev, value);
 225         }
 226         break;
 227     case VIRTIO_MMIO_GUESTFEATURESSEL:
 228         proxy->guest_features_sel = value;
 229         break;
 230     case VIRTIO_MMIO_GUESTPAGESIZE:
 231         proxy->guest_page_shift = ctz32(value);
 232         if (proxy->guest_page_shift > 31) {
 233             proxy->guest_page_shift = 0;
 234         }
 235         DPRINTF("guest page size %" PRIx64 " shift %d\n", value,
 236                 proxy->guest_page_shift);
 237         break;
 238     case VIRTIO_MMIO_QUEUESEL:
 239         if (value < VIRTIO_PCI_QUEUE_MAX) {
 240             vdev->queue_sel = value;
 241         }
 242         break;
 243     case VIRTIO_MMIO_QUEUENUM:
 244         DPRINTF("mmio_queue write %d max %d\n", (int)value, VIRTQUEUE_MAX_SIZE);
 245         virtio_queue_set_num(vdev, vdev->queue_sel, value);
 246         break;
 247     case VIRTIO_MMIO_QUEUEALIGN:
 248         virtio_queue_set_align(vdev, vdev->queue_sel, value);
 249         break;
 250     case VIRTIO_MMIO_QUEUEPFN:
 251         if (value == 0) {
 252             virtio_reset(vdev);
 253         } else {
 254             virtio_queue_set_addr(vdev, vdev->queue_sel,
 255                                   value << proxy->guest_page_shift);
 256         }
 257         break;
 258     case VIRTIO_MMIO_QUEUENOTIFY:
 259         if (value < VIRTIO_PCI_QUEUE_MAX) {
 260             virtio_queue_notify(vdev, value);
 261         }
 262         break;
 263     case VIRTIO_MMIO_INTERRUPTACK:
 264         vdev->isr &= ~value;
 265         virtio_update_irq(vdev);
 266         break;
 267     case VIRTIO_MMIO_STATUS:
 268         virtio_set_status(vdev, value & 0xff);
 269         if (vdev->status == 0) {
 270             virtio_reset(vdev);
 271         }
 272         break;
 273     case VIRTIO_MMIO_MAGIC:
 274     case VIRTIO_MMIO_VERSION:
 275     case VIRTIO_MMIO_DEVICEID:
 276     case VIRTIO_MMIO_VENDORID:
 277     case VIRTIO_MMIO_HOSTFEATURES:
 278     case VIRTIO_MMIO_QUEUENUMMAX:
 279     case VIRTIO_MMIO_INTERRUPTSTATUS:
 280         DPRINTF("write to readonly register\n");
 281         break;
 282
 283     default:
 284         DPRINTF("bad register offset\n");
 285     }
 286 }
 287
 288 static const MemoryRegionOps virtio_mem_ops = {
 289     .read = virtio_mmio_read,
 290     .write = virtio_mmio_write,
 291     .endianness = DEVICE_NATIVE_ENDIAN,
 292 };
 293
 294 static void virtio_mmio_update_irq(DeviceState *opaque, uint16_t vector)
 295 {
 296     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
 297     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
 298     int level;
 299
 300     if (!vdev) {
 301         return;
 302     }
 303     level = (vdev->isr != 0);
 304     DPRINTF("virtio_mmio setting IRQ %d\n", level);
 305     qemu_set_irq(proxy->irq, level);
 306 }
 307
 308 static int virtio_mmio_load_config(DeviceState *opaque, QEMUFile *f)
 309 {
 310     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
 311
 312     proxy->host_features_sel = qemu_get_be32(f);
 313     proxy->guest_features_sel = qemu_get_be32(f);
 314     proxy->guest_page_shift = qemu_get_be32(f);
 315     return 0;
 316 }
 317
 318 static void virtio_mmio_save_config(DeviceState *opaque, QEMUFile *f)
 319 {
 320     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
 321
 322     qemu_put_be32(f, proxy->host_features_sel);
 323     qemu_put_be32(f, proxy->guest_features_sel);
 324     qemu_put_be32(f, proxy->guest_page_shift);
 325 }
 326
 327 static void virtio_mmio_reset(DeviceState *d)
 328 {
 329     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
 330
 331     virtio_bus_reset(&proxy->bus);
 332     proxy->host_features_sel = 0;
 333     proxy->guest_features_sel = 0;
 334     proxy->guest_page_shift = 0;
 335 }
 336
 337 /* virtio-mmio device */
 338
 339 /* This is called by virtio-bus just after the device is plugged. */
 340 static void virtio_mmio_device_plugged(DeviceState *opaque)
 341 {
 342     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
 343     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
 344
 345     virtio_add_feature(&vdev->host_features, VIRTIO_F_NOTIFY_ON_EMPTY);
 346 }
 347
 348 static void virtio_mmio_realizefn(DeviceState *d, Error **errp)
 349 {
 350     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
 351     SysBusDevice *sbd = SYS_BUS_DEVICE(d);
 352
 353     qbus_create_inplace(&proxy->bus, sizeof(proxy->bus), TYPE_VIRTIO_MMIO_BUS,
 354                         d, NULL);
 355     sysbus_init_irq(sbd, &proxy->irq);
 356     memory_region_init_io(&proxy->iomem, OBJECT(d), &virtio_mem_ops, proxy,
 357                           TYPE_VIRTIO_MMIO, 0x200);
 358     sysbus_init_mmio(sbd, &proxy->iomem);
 359 }
 360
 361 static void virtio_mmio_class_init(ObjectClass *klass, void *data)
 362 {
 363     DeviceClass *dc = DEVICE_CLASS(klass);
 364
 365     dc->realize = virtio_mmio_realizefn;
 366     dc->reset = virtio_mmio_reset;
 367     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 368 }
 369
 370 static const TypeInfo virtio_mmio_info = {
 371     .name          = TYPE_VIRTIO_MMIO,
 372     .parent        = TYPE_SYS_BUS_DEVICE,
 373     .instance_size = sizeof(VirtIOMMIOProxy),
 374     .class_init    = virtio_mmio_class_init,
 375 };
 376
 377 /* virtio-mmio-bus. */
 378
 379 static void virtio_mmio_bus_class_init(ObjectClass *klass, void *data)
 380 {
 381     BusClass *bus_class = BUS_CLASS(klass);
 382     VirtioBusClass *k = VIRTIO_BUS_CLASS(klass);
 383
 384     k->notify = virtio_mmio_update_irq;
 385     k->save_config = virtio_mmio_save_config;
 386     k->load_config = virtio_mmio_load_config;
 387     k->device_plugged = virtio_mmio_device_plugged;
 388     k->has_variable_vring_alignment = true;
 389     bus_class->max_dev = 1;
 390 }
 391
 392 static const TypeInfo virtio_mmio_bus_info = {
 393     .name          = TYPE_VIRTIO_MMIO_BUS,
 394     .parent        = TYPE_VIRTIO_BUS,
 395     .instance_size = sizeof(VirtioBusState),
 396     .class_init    = virtio_mmio_bus_class_init,
 397 };
 398
 399 static void virtio_mmio_register_types(void)
 400 {
 401     type_register_static(&virtio_mmio_bus_info);
 402     type_register_static(&virtio_mmio_info);
 403 }
 404
 405 type_init(virtio_mmio_register_types)