static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) { VirtIOBlock *s = VIRTIO_BLK(vdev); BlockConf *conf = &s->conf.conf; struct virtio_blk_config blkcfg; uint64_t capacity; int blk_size = conf->logical_block_size; bdrv_get_geometry(s->bs, &capacity); memset(&blkcfg, 0, sizeof(blkcfg)); virtio_stq_p(vdev, &blkcfg.capacity, capacity); virtio_stl_p(vdev, &blkcfg.seg_max, 128 - 2); virtio_stw_p(vdev, &blkcfg.cylinders, conf->cyls); virtio_stl_p(vdev, &blkcfg.blk_size, blk_size); virtio_stw_p(vdev, &blkcfg.min_io_size, conf->min_io_size / blk_size); virtio_stw_p(vdev, &blkcfg.opt_io_size, conf->opt_io_size / blk_size); blkcfg.heads = conf->heads; /* * We must ensure that the block device capacity is a multiple of * the logical block size. If that is not the case, let's use * sector_mask to adopt the geometry to have a correct picture. * For those devices where the capacity is ok for the given geometry * we don't touch the sector value of the geometry, since some devices * (like s390 dasd) need a specific value. Here the capacity is already * cyls*heads*secs*blk_size and the sector value is not block size * divided by 512 - instead it is the amount of blk_size blocks * per track (cylinder). */ if (bdrv_getlength(s->bs) / conf->heads / conf->secs % blk_size) { blkcfg.sectors = conf->secs & ~s->sector_mask; } else { blkcfg.sectors = conf->secs; } blkcfg.size_max = 0; blkcfg.physical_block_exp = get_physical_block_exp(conf); blkcfg.alignment_offset = 0; blkcfg.wce = bdrv_enable_write_cache(s->bs); memcpy(config, &blkcfg, sizeof(struct virtio_blk_config)); }