Re: [Qemu-devel] [PATCH] wdt_i6300esb: fix vmstate versioning

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

On Wed, Jun 12, 2013 at 09:42:14PM +0100, Peter Maydell wrote:
> On 12 June 2013 21:11, mdroth <mdroth@linux.vnet.ibm.com> wrote:
> > On Tue, May 21, 2013 at 05:32:57PM -0500, Michael Roth wrote:
> >> When this VMSD was introduced it's version fields were set to
> >> sizeof(I6300State), making them essentially random from build to build,
> >> version to version.
> >>
> >> To fix this, we lock in a high version id and low minimum version id to
> >> support old->new migration from all prior versions of this device's
> >> state. This should work since the device state has not changed since
> >> its introduction.
> >>
> >> The potentially breaks migration from 1.5+ to 1.5, but since the
> >> versioning was essentially random prior to this patch, new->old
> >> migration was not consistently functional to begin with.
> >>
> >> Reported-by: Nicholas Thomas <nick@bytemark.co.uk>
> >> Suggested-by: Peter Maydell <peter.maydell@linaro.org>
> >> Cc: qemu-stable@nongnu.org
> >> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
> >
> > CC'ing qemu-trivial. Looking to get this in for 1.5.1
> 
> This is a good patch but it definitely doesn't seem like
> -trivial material to me. -trivial isn't "way to get patches
> in that would otherwise fall through the cracks" :-)

I honestly thought it was trivial once all the considerations were
documented, but reading through it all again makes my head hurt a
bit so you're probably right.

Anthony, Juan?

> 
> thanks
> -- PMM
>