We have been complaining for a long time about how the floppy controller and
floppy drives are combined in a single qdev device and how this makes the
device awkward to work with because it behaves different from all other block
devices.
The latest reason to complain was when I noticed that using qdev device names
in QMP commands (e.g. for media change) doesn't really work when only the
controller is a qdev device, but the drives aren't.
So I decided to have a go at it, and this is the result.
It doesn't actually change any of the inner workings of the floppy controller,
but it wires things up differently on the qdev layer so that a floppy
controller now exposes a bus on which the floppy drives sit. This results in a
structure that is similar to IDE where the actual drive state is still in the
controller and the qdev device basically just contains the qdev properties -
not pretty, but quite workable.
The commit message of patch 3 explains how to use it. In short, there is a
'-device floppy' now and it does what you would expect if you ever used ide-cd.
The other problem is old command lines, especially those using things like
'-global isa-fdc,driveA=...'. In order to keep them working, we need to forward
the property to an internally created floppy drive device. This is a bit like
usb-storage, which we know is ugly, but works well enough in practice. The good
news here is that in contrast to usb-storage, the floppy controller only does
the forwarding for legacy configurations; as soon as you start using '-device
floppy', it doesn't happen any more.
So as you may have expected, this conversion doesn't result in a perfect
device, but I think it's definitely an improvement over the old state. I hope
you like it despite the warts. :-)
v2:
- Added patch 4 (qemu-iotests case for floppy config on the command line)
- Patch 2: Create a floppy device only if a BlockBackend exists instead of
always creating two of them
- Patch 2: Initialise drive->fdctrl even if no drive is attached, it is
accessed anyway during migration
- Patch 3: Keep 'type' qdev property and FDrive->drive in sync
- Patch 3: Removed if with condition that is always true
Kevin Wolf (4):
fdc: Add a floppy qbus
fdc: Add a floppy drive qdev
fdc: Move qdev properties to FloppyDrive
qemu-iotests: Test creating floppy drives
hw/block/fdc.c | 263 --
tests/qemu-iotests/172 | 242 +
tests/qemu-iotests/172.out | 1205
tests/qemu-iotests/group |1 +
vl.c |1 +
5 files changed, 1668 insertions(+), 44 deletions(-)
create mode 100755 tests/qemu-iotests/172
create mode 100644 tests/qemu-iotests/172.out
--
1.8.3.1
