static uint32_t syborg_virtio_readb(void *opaque, target_phys_addr_t offset)
{
SyborgVirtIOProxy *s = opaque;
VirtIODevice *vdev = s->vdev;
DPRINTF("readb 0x%x\n", (int)offset);
if (offset >= SYBORG_VIRTIO_CONFIG) {
return virtio_config_readb(vdev, offset - SYBORG_VIRTIO_CONFIG);
}
BADF("Bad byte read offset 0x%x\n", (int)offset);
return -1;
}
static uint64_t virtio_mmio_read(void *opaque, hwaddr offset, unsigned size)
{
VirtIOMMIOProxy *proxy = (VirtIOMMIOProxy *)opaque;
VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
DPRINTF("virtio_mmio_read offset 0x%x\n", (int)offset);
if (!vdev) {
/* If no backend is present, we treat most registers as
* read-as-zero, except for the magic number, version and
* vendor ID. This is not strictly sanctioned by the virtio
* spec, but it allows us to provide transports with no backend
* plugged in which don't confuse Linux's virtio code: the
* probe won't complain about the bad magic number, but the
* device ID of zero means no backend will claim it.
*/
switch (offset) {
case VIRTIO_MMIO_MAGIC:
return VIRT_MAGIC;
case VIRTIO_MMIO_VERSION:
return VIRT_VERSION;
case VIRTIO_MMIO_VENDORID:
return VIRT_VENDOR;
default:
return 0;
}
}
if (offset >= VIRTIO_MMIO_CONFIG) {
offset -= VIRTIO_MMIO_CONFIG;
switch (size) {
case 1:
return virtio_config_readb(vdev, offset);
case 2:
return virtio_config_readw(vdev, offset);
case 4:
return virtio_config_readl(vdev, offset);
default:
abort();
}
}
if (size != 4) {
DPRINTF("wrong size access to register!\n");
return 0;
}
switch (offset) {
case VIRTIO_MMIO_MAGIC:
return VIRT_MAGIC;
case VIRTIO_MMIO_VERSION:
return VIRT_VERSION;
case VIRTIO_MMIO_DEVICEID:
return vdev->device_id;
case VIRTIO_MMIO_VENDORID:
return VIRT_VENDOR;
case VIRTIO_MMIO_HOSTFEATURES:
if (proxy->host_features_sel) {
return 0;
}
return vdev->host_features;
case VIRTIO_MMIO_QUEUENUMMAX:
if (!virtio_queue_get_num(vdev, vdev->queue_sel)) {
return 0;
}
return VIRTQUEUE_MAX_SIZE;
case VIRTIO_MMIO_QUEUEPFN:
return virtio_queue_get_addr(vdev, vdev->queue_sel)
>> proxy->guest_page_shift;
case VIRTIO_MMIO_INTERRUPTSTATUS:
return atomic_read(&vdev->isr);
case VIRTIO_MMIO_STATUS:
return vdev->status;
case VIRTIO_MMIO_HOSTFEATURESSEL:
case VIRTIO_MMIO_GUESTFEATURES:
case VIRTIO_MMIO_GUESTFEATURESSEL:
case VIRTIO_MMIO_GUESTPAGESIZE:
case VIRTIO_MMIO_QUEUESEL:
case VIRTIO_MMIO_QUEUENUM:
case VIRTIO_MMIO_QUEUEALIGN:
case VIRTIO_MMIO_QUEUENOTIFY:
case VIRTIO_MMIO_INTERRUPTACK:
DPRINTF("read of write-only register\n");
return 0;
default:
DPRINTF("bad register offset\n");
return 0;
}
return 0;
}
