Re: [Qemu-arm] [Qemu-devel] [PATCH v2 6/6] hw/arm/virt: Set minimum_page_bits to 12

[Andrew Jones]

On Wed, Jun 22, 2016 at 01:02:04PM +0100, Peter Maydell wrote:
> On 22 June 2016 at 12:54, Dr. David Alan Gilbert <address@hidden> wrote:
> > * Peter Maydell (address@hidden) wrote:
> >> On 22 June 2016 at 12:35, Dr. David Alan Gilbert <address@hidden> wrote:
> >> > Yes, my hope is that any versioned machine type should migrate to
> >> > a newer qemu with the same machine type set.
> >> >
> >> > There are really two separate things that we state with the machine
> >> > versioning:
> >> >   a) that the guest view is the same
> >> >   b) that the migration format is the same
> >>
> >> Well, this is true for PC.
> >
> > PC, ppc/spapr, and I think s390.
> >
> >> But my impression when we started
> >> applying versioned machine types to ARM virt was that it was
> >> signing up to (a) but not (yet) (b)...
> >
> > So that would make ARM special; the problem is we have no way
> > to communicate to the user that it's special.
> 
> Is anybody testing that migration between versions for
> virt works?

We've only tested migration between identically configured hosts
so far. This is partly due to the fact that we haven't released
a RHEL machine type yet, i.e. we're working towards a RHEL-7.3
machine type on a RHEL-7.3 QEMU, which will be the first and only
we have. When we have a development 7.4 branch to work with then
we'd test a 7.3 machine migration from a 7.3 host to a 7.4 host
as well.

I'll add trying an upstream 2.6 machine type migration from a
2.6 QEMU to a latest QEMU to our TODO.

Thanks,
drew