[PATCH 0/2] powerpc/xive: fix CPU hot unplug

[Cédric Le Goater]

On 10/02/2017 06:52 PM, Benjamin Herrenschmidt wrote:
> On Mon, 2017-10-02 at 18:27 +0200, Cédric Le Goater wrote:
>> On 09/23/2017 10:26 AM, Cédric Le Goater wrote:
>>> Hi,
>>>
>>> Here are a couple of small fixes to support CPU hot unplug. There are
>>> still some issues to be investigated as, in some occasions, after a
>>> couple of plug and unplug, the cpu which was removed receives a 'lost'
>>> interrupt. This showed to be the decrementer under QEMU.
>>
>> So this seems to be a QEMU issue only which can be solved by 
>> removing the DEE bit from the LPCR on P9 processor when the CPU 
>> is stopped in rtas. PECE3 bit on P8 processors. 
> 
> It should be the same bit no ?

yes and it is for the QEMU side of the world. 

C.
 
>> I think these patches are valuable fixes for 4.14. The first 
>> is trivial and the second touches the common xive part but it
>> is only called on the pseries platform.  
>>
>> Could you please take a look ? 
>>
>> Thanks,
>>
>> C. 
>>
>>> Nevertheless, these patches are required and provide a significant
>>> improvement to support CPU removal.
>>>
>>> Tested under a phyp and a XIVE QEMU model for pseries.
>>>
>>> Thanks,
>>>
>>> C.
>>>
>>> Cédric Le Goater (2):
>>>   powerpc/xive: fix IPI reset
>>>   powerpc/xive: fix cpu removal
>>>
>>>  arch/powerpc/sysdev/xive/common.c | 8 ++++++++
>>>  arch/powerpc/sysdev/xive/spapr.c  | 4 ++++
>>>  2 files changed, 12 insertions(+)
>>>