[PATCH v7 0/8] Add Qemu to SeaBIOS LCHS interface

From: Sam Eiderman via <qemu-devel@nongnu.org>
To: qemu-devel@nongnu.org
Cc: kwolf@redhat.com, qemu-block@nongnu.org, arbel.moshe@oracle.com,
	seabios@seabios.org, kevin@koconnor.net, liran.alon@oracle.com,
	kraxel@redhat.com, sameid@google.com, karl.heubaum@oracle.com
Subject: [PATCH v7 0/8] Add Qemu to SeaBIOS LCHS interface
Date: Wed, 25 Sep 2019 14:06:31 +0300	[thread overview]
Message-ID: <20190925110639.100699-1-sameid@google.com> (raw)

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:

Fix missing parenthesis check in
    "hd-geo-test: Add tests for lchs override"

v3:

* Rename fw_cfg key to "bios-geometry".
* Remove "extendible" interface.
* Add cpu_to_le32 fix as Laszlo suggested or big endian hosts
* Fix last qtest commit - automatic docker tester for some reason does not have qemu-img set

v4:

* Change fw_cfg interface from mixed textual/binary to textual only

v5:

* Fix line > 80 chars in tests/hd-geo-test.c

v6:

* Small fixes for issues pointed by Max
* (&conf->conf)->lcyls to conf->conf.lcyls and so on
* Remove scsi_unrealize from everything other than scsi-hd
* Add proper include to sysemu.h
* scsi_device_unrealize() after scsi_device_purge_requests()

v7:

* Adapted last commit (tests) to changes in qtest

Sam Eiderman (8):
  block: Refactor macros - fix tabbing
  block: Support providing LCHS from user
  bootdevice: Add interface to gather LCHS
  scsi: Propagate unrealize() callback to scsi-hd
  bootdevice: Gather LCHS from all relevant devices
  bootdevice: Refactor get_boot_devices_list
  bootdevice: FW_CFG interface for LCHS values
  hd-geo-test: Add tests for lchs override

 bootdevice.c             | 148 ++++++++--
 hw/block/virtio-blk.c    |   6 +
 hw/ide/qdev.c            |   7 +-
 hw/nvram/fw_cfg.c        |  14 +-
 hw/scsi/scsi-bus.c       |  16 ++
 hw/scsi/scsi-disk.c      |  12 +
 include/hw/block/block.h |  22 +-
 include/hw/scsi/scsi.h   |   1 +
 include/sysemu/sysemu.h  |   4 +
 tests/Makefile.include   |   2 +-
 tests/hd-geo-test.c      | 589 +++++++++++++++++++++++++++++++++++++++
 11 files changed, 780 insertions(+), 41 deletions(-)

-- 
2.23.0.351.gc4317032e6-goog