On 20/04/20 23:50, Davidlohr Bueso wrote: > On Mon, 20 Apr 2020, Paolo Bonzini wrote: > >> On 20/04/20 22:56, Davidlohr Bueso wrote: >>> On Mon, 20 Apr 2020, Marc Zyngier wrote: >>> >>>> This looks like a change in the semantics of the tracepoint. Before >>>> this >>>> change, 'waited' would have been true if the vcpu waited at all. Here, >>>> you'd >>>> have false if it has been interrupted by a signal, even if the vcpu >>>> has waited >>>> for a period of time. >>> >>> Hmm but sleeps are now uninterruptible as we're using TASK_IDLE. >> >> Hold on, does that mean that you can't anymore send a signal in order to >> kick a thread out of KVM_RUN? Or am I just misunderstanding? > > Considering that the return value of the interruptible wait is not > checked, I would not think this breaks KVM_RUN. What return value? kvm_vcpu_check_block checks signal_pending, so you could have a case where the signal is injected but you're not woken up. Admittedly I am not familiar with how TASK_* work under the hood, but it does seem to be like that. Paolo
