On 26.06.19 14:39, Sam Eiderman wrote: > v1: > > Non-standard logical geometries break under QEMU. > > A virtual disk which contains an operating system which depends on > logical geometries (consistent values being reported from BIOS INT13 > AH=08) will most likely break under QEMU/SeaBIOS if it has non-standard > logical geometries - for example 56 SPT (sectors per track). > No matter what QEMU will guess - SeaBIOS, for large enough disks - will > use LBA translation, which will report 63 SPT instead. > > In addition we can not enforce SeaBIOS to rely on phyiscal geometries at > all. A virtio-blk-pci virtual disk with 255 phyiscal heads can not > report more than 16 physical heads when moved to an IDE controller, the > ATA spec allows a maximum of 16 heads - this is an artifact of > virtualization. > > By supplying the logical geometies directly we are able to support such > "exotic" disks. > > We will use fw_cfg to do just that.
(From a block perspective,) I didn’t find anything too bad, so: Acked-by: Max Reitz <mre...@redhat.com>
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