[Qemu-devel] qdevification of xen_disk

[Kevin Wolf]

Hi Stefano and all,

while working on some part of the QEMU block layer infrastructure that
requires going from a BlockBackend to the qdev DeviceState, I noticed
that xen_disk is still not qdevified after all the years. It's the last
device, and has been for a while, that is blocking the necessary changes
in the block layer.

Specifically, I'm talking about the blk_attach_dev_nofail() and
blk_detach_dev() functions (and related ones, which don't seem to be
used by xen_disk though), which must be converted from accepting a void*
for the device to DeviceState*.

I think in theory it shouldn't be too hard to build a minimal qdev
device between xen_disk and the block layer. If you want me to, I can
try to do that - however, I don't have a Xen setup to actually test the
result, so if things break, you get to keep the pieces. If someone else
would like to look into this in the next few days, that might be the
better option.

In any case, we need to do something to make xen_disk compatible with
the modern (well, not _that_ modern any more) infrastructure that all
other devices use.

Kevin