Re: [Qemu-devel] [PATCH] target-ppc: Add POWER8E_v2.1 CPU model.

[David Gibson <david@gibson.dropbear.id.au>]

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On Wed, Jul 08, 2015 at 04:40:27PM +1000, Alexey Kardashevskiy wrote:
> On 07/08/2015 03:37 PM, David Gibson wrote:
> >On Wed, Jul 08, 2015 at 02:10:28PM +1000, Alexey Kardashevskiy wrote:
> >>On 07/08/2015 01:43 PM, David Gibson wrote:
> >>>From: Andrea Bolognani <abologna@redhat.com>
> >>>
> >>>Add a missing PVR value for the POWER8E v2.1 CPU.  Information taken
> >>>from the kernel cputable.
> >>>
> >>>Signed-off-by: Andrea Bolognani <abologna@redhat.com>
> >>>Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> >>>---
> >>>  target-ppc/cpu-models.c | 4 +++-
> >>>  target-ppc/cpu-models.h | 1 +
> >>>  2 files changed, 4 insertions(+), 1 deletion(-)
> >>>
> >>>Alex,
> >>>
> >>>Not sure if this counts as a bugfix which can be merged now we're in
> >>>the hard freeze.  The lack of it does mean we can't work on one of our
> >>>dev machines which has this CPU.
> >>
> >>
> >>Why is this a stopper? We stopped bothering with exact PVRs some time ago
> >>and -cpu POWER8 or -cpu host still work.
> >
> >Andrea, can you clarify?
> >
> >I think it's because libvirt likes to specify a specific CPU - and if
> >it gets the new PVR from the host, qemu won't understand it.
> 
> 
> A specific CPU in this case is "POWER8", I added this specifically for
> libvirt (to allow migration between all versions of POWER8), it should not
> use versioned CPUs and it does not in powerkvm.

Uh.. won't that make qemu attempt to set a specific PVR, though -
which will fail with recent KVM if it's not *exactly* the same as the
host PVR.

> 
> There is actually a patch to make this PVR masking/subclassing nicer, I
> replied to it with adding you in cc:, please have a look. Andreas Faerber
> had objections which I did not really grasp then.
> 
> 

-- 
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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