On Wed, 2009-06-10 at 20:27 +0100, Jamie Lokier wrote:
Michael S. Tsirkin wrote:
I think the right long term answer to all this is a way to get QEMU to
dump it's current machine configuration in glorious detail as a file
which can be reloaded as a machine configuration.
And then we'll have the same set of problems there.
We will, and the solution will be the same: options to create devices
as they were in older versions of QEMU. It only needs to cover device
features which matter to guests, not every bug fix.
However with a machine configuration which is generated by QEMU,
there's less worry about proliferation of obscure options, compared
with the command line. You don't necessarily have to document every
backward-compatibility option in any detail, you just have to make
sure it's written and read properly, which is much the same thing as
the snapshot code does.
This is a sensible plan, but I don't think we should mix these compat
options in with the VM manager supplied configuration.
There are two problems with that approach.
= Problem 1 - VM manager needs to parse qemu config =
Your proposal implies:
- VM manager supplies a basic configuration to qemu
- It then immediately asks qemu for a dump of the machine
configuration in all its glorious detail and retains that
- If the VM manager wishes to add a new device it needs to parse the
qemu config and add it, rather than just generate an entirely new