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. 

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(+)