Re: [PATCH v2] kvm: Replace vcpu->swait with rcuwait

Davidlohr Bueso
2020-04-20T21:53:46Z

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.

Thanks,
Davidlohr