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

[Michael Roth <mdroth@linux.vnet.ibm.com>]

On Tue, Apr 03, 2012 at 11:43:57PM +0300, Dor Laor wrote:
> On 04/03/2012 05:43 PM, Markus Armbruster wrote:
> >I'm afraid my notes are rather rough...
> >
> >* 1.1
> >   soft freeze apr 15th (less than two weeks)
> >   hard freeze may 1
> >   three months cycle for 1.2
> >   stable machine types only every few releases?  "pc-next"
> >
> >* Maintainers, got distracted and my notes make no sense, sorry
> >
> >* MSI injection to KVM irqchips from userspace devices models
> >
> >* qemu-kvm tree: working towards upstream merge
> >
> >   not much left, mostly device assignment
> >
> >* Migration: vmstate and visitors, decoupling the wire format
> >   why not ASN.1
> 
> Curiosity kills me of waiting for next week's meeting to get the answer

I believe when this had come up in the past the plan was to use ASN.1
 for the wire protocol, but not to address the decoupling problem.

Theoretically it could handle both, but I believe that requires defining
device structures using ASN.1 definitions, which probably isn't suitable
for devices since it results in high level structures which require
special accessors (at least for the libraries I've looked at)

An IDL compiler that generates visitors based on a simple device code
annotations still seems to be the leading option.

Previously I'd jumped the gun a bit by piggy-backing off vmstate to get at
the protocol side, but that permanently baked QEMUFile markers into the
wire protocol which was the wrong approach.

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.

> 
> >
> >* qtest: test cases wanted
> >
> 
>