[PATCH v2 0/12] Hypervisor-mode KVM on POWER7

Olof Johansson olof at lixom.net
Wed Jun 1 15:31:31 EST 2011


On Tue, May 31, 2011 at 5:35 AM, Paul Mackerras <paulus at samba.org> wrote:
> On Tue, May 31, 2011 at 12:40:31PM +0200, Alexander Graf wrote:
>
>> Thinking about the testability of this a bit more ... how much
>> effort would it be to get this code running on a 970MP with SLOF?
>> There should only be a few POWER7 specific pieces, right?
>
> Do you have a 970MP that has a usable hypervisor mode, i.e. not an
> Apple machine?  The 970s in Apple machines have the HV hard-wired to
> 1, which means they do have a hypervisor mode but it isn't any use.
>
> If you do have such a machine, then we would have to look at some
> details like the instruction sequence for the partition switch, and
> make sure we don't try to use SMT4 mode.  Also, I believe we will have
> to flush the TLB on partition switches, since Power processors prior
> to POWER7 didn't tag the TLB entries with the partition ID.
>
> So it should be quite feasible if you have a non-Apple machine.
> I will check whether the 970MP machines that Terrasoft were
> distributing would be suitable.  We have one of them in the lab.

PA6T is closer to power7 than 970 when it comes to hypervisor features
(i.e. VRMA, LPCR, mediated interrupts are all available there). I can
try to find some old hardware if there's any interest from anyone to
use it.

Of course, there isn't much of a roadmap. But 970 isn't really going
anywhere either. :)


-Olof


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