On 24/06/2022 11.20, Christian Borntraeger wrote:
Am 24.06.22 um 10:50 schrieb Thomas Huth:
The s390-ccw bios fails to boot if the boot disk is a virtio-blk
disk with a sector size of 4096. For example:
dasdfmt -b 4096 -d cdl -y -p -M quick /dev/dasdX
fdasd -a /dev/dasdX
install a guest onto /dev/dasdX1 using virtio-blk
qemu-system-s390x -nographic -hda /dev/dasdX1
Interestingly enough a real DASD (dasdX and not dasdX1) did work in the
past and I also successfully uses an NVMe disk. So I guess the NVMe
was 512 byte sector size then?
If you're using a full DASD, I think this was working thanks to the
virtio_disk_is_eckd() function recognizing the geometry.
For NVMe disk - no clue. It either used 512 sectors, or it was at least
accidentally still able to deal with the 512-byte sector requests after
virtio_assume_scsi() "fixed" up the geometry. If you've got some spare
minutes and still have access to those disks, it would be interesting to
know if the boot still works there with my patches applied.
Thomas
