* Avi Kivity <avi@xxxxxxxxxx> wrote: > Marcelo Tosatti wrote: >> KVM uses a function call IPI to cause the exit of a guest running on a >> physical cpu. For virtual interrupt notification there is no need to >> wait on IPI receival, or to execute any function. >> >> This is exactly what the reschedule IPI does, without the overhead >> of function IPI. So use it instead of smp_call_function_single in >> kvm_vcpu_kick. >> >> Also change the "guest_mode" variable to a bit in vcpu->requests, and >> use that to collapse multiple IPI's that would be issued between the >> first one and zeroing of guest mode. >> >> This allows kvm_vcpu_kick to called from interrupt context. >> > > Looks good. The only worry I have is that we depend on > smp_reschedule_interrupt() being a no-op. I guess that's a > reasonable assumption though. It's a reasonable current assumption - but it might change in the future - so please also put it into the changelog that KVM will revert it or fix it differently if the scheduler grows some functionality there. Ingo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
