[Qemu-devel] [SeaBIOS] [PATCH v3 0/4] Add Qemu to SeaBIOS LCHS interface

[Sam Eiderman <shmuel.eiderman@oracle.com>]

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(-)

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2.13.3