On Wednesday 27 August 2014 04:10 PM, Alexander Graf wrote: > > > On 25.08.14 15:45, Aravinda Prasad wrote: >> It is possible for multi-processors to experience machine >> check at or about the same time. As per PAPR, subsequent >> processors serialize waiting for the first processor to >> issue the ibm,nmi-interlock call. >> >> The second processor retries if the first processor which >> received a machine check is still reading the error log >> and is yet to issue ibm,nmi-interlock call. >> >> This patch implements this functionality. >> >> Signed-off-by: Aravinda Prasad <aravi...@linux.vnet.ibm.com> > > This patch doesn't make any sense. Both threads will issue an HCALL > which will get locked inside of QEMU, so we'll never see the case where > both hypercalls get processed at the same time.
AFAIK, only one thread can succeed entering qemu upon parallel hcall from different guest CPUs as it is gated by a lock. Hence one hcall is processed at a time. As per PAPR, we don't want any other KVMPPC_H_REPORT_ERR hcall to be processed at the same time and further KVMPPC_H_REPORT_ERR hcall thus issued should wait until the OS issues ibm,nmi-interlock. Thanks for the review. Regards, Aravinda > > > Alex > -- Regards, Aravinda
