Re: [Qemu-ppc] [RFC PATCH] spapr: add initial ibm, client-architecture-support rtas call support

[Benjamin Herrenschmidt]

On Wed, 2013-09-04 at 21:40 +1000, Alexey Kardashevskiy wrote:
> One of the examples (came from Paul) is:
> the host runs on POWER8, the guest boots a kernel which is capable of
> POWER7 only + POWER7-compat. We do this reboot tweak and boot in
> POWER7-compat mode. Then the guest does "yum update" and gets POWER8
> kernel
> installed so when it reboots, it will boot in normal POWER8 mode.
> Everybody
> is happy.
> 
> Having POWER7-compat mode set from the very beginning will break this
> behaviour.

But it will allow migrating that partition to a P7 machine. It's
important to be able to specify the compat mode for that reason, to
create guests that can be migrated to older machines.

Cheers,
Ben.