Re: [Qemu-devel] [Qemu-ppc] KVM-PR is broken with current QEMU

[Thomas Huth]

On 20.09.2016 16:39, Cédric Le Goater wrote:
> On 09/20/2016 04:24 PM, Thomas Huth wrote:
>> On 20.09.2016 16:04, Cédric Le Goater wrote:
[...]
>>> There are other issues after in the guest (kernel crashing). But I think
>>> these are related to TM which is not supported in KVM-PR. I am not sure
>>> where we are on that point.
>>
>> There was a patch some months ago:
>>
>> https://lists.gnu.org/archive/html/qemu-ppc/2016-04/msg00046.html
>>
>> ... but I think it has never been included, as far as I can see.
> 
> and with that patch, the guest fully boots. But David had some concerns
> on the way it is done. It would be nice to put some cycle on this. 

Looking at the mail thread, I think TM should be currently disabled for
both, KVM-PR and TCG, i.e. only enabled for KVM-HV. The TM support in
TCG is just fake, since TBEGIN always fails.
Once we've got proper TM support in TCG, this can be easily changed
within QEMU. And once we've got TM support in KVM-PR, I think we should
also introduce a capability flag to KVM which can be used to inform QEMU
about this.

So I think Anton's patch currently just lacks the check for TCG.
Anton, if you've got some spare minutes, could you maybe send an updated
version of that patch?

 Thanks,
  Thomas