Il 12/12/2012 20:23, Michael S. Tsirkin ha scritto:
>>> Saving inuse counter is useless. We need to know which requests
>>> are outstanding if we want to retry them on remote.
>>
>> And that's what virtio-blk and virtio-scsi have been doing for years.
>
> I don't see it - all I see in save is virtio_save.
static void virtio_blk_save(QEMUFile *f, void *opaque)
{
VirtIOBlock *s = opaque;
VirtIOBlockReq *req = s->rq;
virtio_save(&s->vdev, f);
while (req) {
qemu_put_sbyte(f, 1);
qemu_put_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
req = req->next;
}
qemu_put_sbyte(f, 0);
}
virtio-scsi does it in virtio_scsi_save_request.
> You need to retry A1 on remote. How do you do that? There's
> no way to find out it has not been completed
> from the ring itself.
virtio_blk_dma_restart_bh and scsi_dma_restart_bh do it.
Paolo
