On Sun, Jun 28, 2020 at 01:04:28AM +1000, Nicholas Piggin wrote: > KVM guests have certain restrictions and performance quirks when > using doorbells. This patch tests for KVM environment in doorbell > setup, and optimises IPI performance: > > - PowerVM guests may now use doorbells even if they are secure. > > - KVM guests no longer use doorbells if XIVE is available. It seems, from the fact that you completely remove kvm_para_available(), that you perhaps haven't tried building with CONFIG_KVM_GUEST=y. Somewhat confusingly, that option is not used or needed when building for a PAPR guest (i.e. the "pseries" platform) but is used on non-IBM platforms using the "epapr" hypervisor interface. If you did intend to remove support for the epapr hypervisor interface then that should have been talked about in the commit message (and would I expect be controversial). So NAK on the kvm_para_available() removal. Paul.
