Re: [Qemu-ppc] [PATCH] spapr: Remove support for explicitly allocated RMAs

[Thomas Huth]

On 03.05.2018 09:10, David Gibson wrote:
> Current POWER cpus allow for a VRMA, a special mapping which describes a
> guest's view of memory when in real mode (MMU off, from the guest's point
> of view).  Older cpus didn't have that which meant that to support a guest
> a special host-contiguous region of memory was needed to give the guest its
> Real Mode Area (RMA).
> 
> KVM used to provide special calls to allocate a contiguous RMA for those
> cases.  This was useful in the early days of KVM on Power to allow it to be
> tested on PowerPC 970 chips as used in Macintosh G5 machines.  Now, those
> machines are so old as to be almost irrelevant.

I still got my YDL PowerStation somewhere in a corner ... but well,
true, I haven't turned on its power since a year or two... or three...

> The normal qemu deprecation process would require this to be marked
> deprecated then removed in 2 releases.  However, this can only be used
> with corresponding support in the host kernel - which was dropped
> years ago (in c17b98cf "KVM: PPC: Book3S HV: Remove code for PPC970
> processors" of 2014-12-03 to be precise).  Therefore it should be ok
> to drop this immediately.

OK, fair.

> Just to be clear this only affects *KVM* guests with PowerPC 970, and those
> already require an ancient host kernel.  TCG guests with PowerPC 970 should
> still work.

Just to be sure: kvm-pr will continue to work on a 970 host, right? In
that case:

Acked-by: Thomas Huth <address@hidden>