@@ -489,7 +489,22 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
stw_raw(&blkcfg.min_io_size, s->conf->min_io_size / blk_size);
stw_raw(&blkcfg.opt_io_size, s->conf->opt_io_size / blk_size);
blkcfg.heads = heads;
- blkcfg.sectors = secs & ~s->sector_mask;
+ /*
+ * We must ensure that the block device capacity is a multiple of
+ * the logical block size. If that is not the case, lets 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 dont 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) / heads / secs % blk_size) {
+ blkcfg.sectors = secs & ~s->sector_mask;
+ } else {
+ blkcfg.sectors = secs;
+ }
blkcfg.size_max = 0;
blkcfg.physical_block_exp = get_physical_block_exp(s->conf);
blkcfg.alignment_offset = 0;