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.
v2:
Rename bootdevices fw_cfg key to bios-geoemtry
v3:
Change fw_cfg interface from mixed binary/textual to textual only Squash commit "config: Add toggle for bootdevice information"
Sam Eiderman (4): geometry: Read LCHS from fw_cfg boot: Reorder functions in boot.c geometry: Add boot_lchs_find_*() utility functions geometry: Apply LCHS values for boot devices
src/Kconfig | 7 ++ src/block.c | 21 ++++- src/block.h | 1 + src/boot.c | 239 +++++++++++++++++++++++++++++++++++++++++---------- src/hw/ahci.c | 1 + src/hw/ata.c | 8 ++ src/hw/esp-scsi.c | 2 + src/hw/lsi-scsi.c | 2 + src/hw/megasas.c | 1 + src/hw/mpt-scsi.c | 2 + src/hw/pvscsi.c | 1 + src/hw/virtio-blk.c | 2 + src/hw/virtio-scsi.c | 2 + src/util.h | 6 ++ 14 files changed, 249 insertions(+), 46 deletions(-)