On Sun, Oct 30, 2016 at 10:12:08PM +1100, David Gibson wrote: > Currently, the pseries machine defaults to running in the "raw" mode of > whatever the CPU version is - that is, without any compatibility options > enabled in the CPU. > > However, migration is only really safe in "raw" mode if source and > destination have exactly the same cpu model. Since HV KVM exposes the > version of the host CPU to the guest, that means "raw" migration between > hosts with different minor revisions isn't strictly safe, although it > generally works in practice. > > To allow this sort of migration in a more clearly defined way, instead > default to running in POWER8 compatibility mode - if an older CPU is used > that will automatically be downgraded to the higest available compatibility > mode. > > Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
Ugh, sorry. When I said minimally tested I did mean that it passed
make check, but unfortunately I was sloppy and this last patch breaks
a bunch of stuff.
> ---
> hw/ppc/spapr.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 2aa0900..8c18dc8 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2194,6 +2194,7 @@ static void spapr_machine_initfn(Object *obj)
> " (required for memory hot-unplug
> support)",
> NULL);
>
> + spapr->max_compat_pvr = CPU_POWERPC_LOGICAL_2_07; /* POWER8 */
> object_property_add(obj, "max-cpu-compat", "str",
> ppc_compat_prop_get, ppc_compat_prop_set,
> NULL, &spapr->max_compat_pvr, &error_fatal);
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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