On 2019-03-29 16:20:51 [+1100], Suraj Jitindar Singh wrote: > > Yeah the kernel must have used msgsndp which isn't implemented for TCG > yet. We use doorbells in linux but only for threads which are on the > same core.
It is msgsndp as per instruction decode. > And when I try to construct a situation with more than 1 thread per > core (e.g. -smp 4,threads=4), I get "TCG cannot support more than 1 > thread/core on a pseries machine". > > So I wonder why the guest thinks it can use msgsndp... I see |# cat /sys/devices/system/cpu/cpu*/topology/thread_siblings_list |0 |1 |2 |3 so this works all well. The problem is when a CPU sends an IPI to itself then linux's doorbell_try_core_ipi() considers this as a valid sibling and here we have the msgsndp. Sebastian