On 20/11/2017 21:44, Michael S. Tsirkin wrote: > Live migrations is supposed to be migrating guest writeable state too. > If you mean migrating RO fields like size, then > I don't think it's a good idea to reuse SET_CONFIG for that. > SET_CONFIG should obey exactly the virtio semantics. > > And I agree, it should say that slave must treat it as a write, > and get config as a read according to virtio semantics. > > If someone needs to pass configuration from qemu to > slave, let's add specific messages with precisely defined semantics.
Fair enough, but I'd add nevertheless a 32-bit flags field to both GET_CONFIG and SET_CONFIG, and document that the slave MUST check that it is zero and otherwise fail. Paolo
