On 11/06/21 14:08, Christian Borntraeger wrote:

quoted

I always interpreted it as "number of times the KVM page table 
management code needed other CPUs to learn about new page tables". 
Whether the broadcast is done in software or hardware shouldn't 
matter; either way I suppose there is still some traffic on the bus 
involved.

My point is that KVM page table management on s390x completely 
piggy-backs on the qemu address space page table management from common 
code for the last level.
And due to the way we handle page tables we also do not teach "other 
CPUs". We always teach the whole system with things like IPTE.

But that just means that you'll have fewer KVM-exclusive and thus nicer 
numbers than x86 or ARM. :)  It still makes sense to count 
gmap_flush_tlb calls.

Paolo