Re: [Qemu-devel] [PATCH] Migration compatibility for serial

[Michael S. Tsirkin]

On Wed, Jun 17, 2015 at 08:52:42AM +0200, Markus Armbruster wrote:
> "Dr. David Alan Gilbert (git)" <address@hidden> writes:
> 
> > From: "Dr. David Alan Gilbert" <address@hidden>
> >
> > Older QEMUs dont understand the new (sub)sections that
> > may be generated in the serial device.   Limit their generation
> > to newer machine types.
> 
> Please explain briefly what state migration can lose with old machine
> types, and how this could impact the guest.  The commits adding the
> subsections should have the information[*].  Pointers to them might
> suffice.
> 
> 
> [*] Should != do; I didn't check.

OTOH if we have flags named after specific portions we skip,
and not after qemu versions, this becomes evident from code.