Re: [Qemu-devel] KVM call minutes April 3

[Dor Laor <dlaor@redhat.com>]

On 04/04/2012 01:37 PM, Michael Roth wrote:
>
> On Apr 4, 2012 2:42 AM, "Paolo Bonzini" <pbonzini@redhat.com
> <mailto:pbonzini@redhat.com>> wrote:
>  >
>  > Il 04/04/2012 03:18, Michael Roth ha scritto:
>  > > Attacking the IDL/schema side first is the more rationale approach.
> From
>  > > there we can potentially generate ASN.1 BER/DER visitors for the
> protocol
>  > > side, or potentially even just vmstate bindings as a start. I've
> recently
>  > > started looking into the latter... it's completely feasible, the only
>  > > downside is it complicates the IDL due requiring support for a lot of
>  > > what are very much vmstate-specific items, but it should be possible to
>  > > do this in a manner where those annotations are self-contained and
>  > > ignorable if we opted to replace vmstate-style declarations.
>  >
>  > We can also keep the current vmstate descriptions, but access fields
>  > from the automatically-generated visitors instead of struct fields.
>  > This keeps the IDL simple.
>
> It may be worthwhile as an incremental step though, one nice thing about
> automatically generated bindings is that with the QIDL Anthony
> prototyped a while back we assume we serialize by default, so changes in
> annotated structs automatically trigger changes in the generated
> bindings unless you explicitly mark fields as immutable/derivable/etc,
> which we can tie into the build or make check to automatically detect
> and bring attention to changes in vmstate. This may be worth the effort
> if we adopt the proposed 4 year migration support cycle for pc-1.0,
> since that'll continue to rely on vmstate even after we move on to an
> IDL and newer protocol.

Beyond ASL/IDL I like to be sure that we're not just translating one 
format to other representation but instead we introduce some new 
functionality like:
  - Ability to negotiate the protocol version
  - Bi-direction data exchange, the sender will send data as a function
    of the target release
    - Include the machine type too
  - Synchronize the entire qemu cmdline and don't relay on management to
    set it up.
    - Along the way, deal w/ hotplug events.

>
>  >
>  > Paolo
>  >
>