Il 02/05/2012 12:18, Christian Borntraeger ha scritto: > Maybe that really points to the problem that we are trying to solve here. > For a dasd device, there is usually a 4096 byte block size and on the host > these 4096 arereported via getss and getpbsz. > The geometry reported by the device driver is usually 15 head and 12 sectors > per track, but actually means 12 sectors of 4096 bytes size (a track ~ 48k). > > What I want to achieve is that the guest view is identical to the host view > for cyls, heads, secs, and all block sizes.
I think what you want is _not_ to have the same view as the host. What you want is simply to have a default that is consistent with what is common on actual s390 disks. Perhaps what we want here is to move the guessing of cyls/head/sector count from -drive to -device, so that virtio-blk-s390 can apply a different default (cyls=auto, head=15, sector=12, and also lbsz=pbsz=4096). Markus, have you ever thought about that? I'm a bit torn because these are media parameters rather than device parameters, on the other hand the same applies to lbsz/pbsz at least. Paolo
