On 27.08.2013, at 09:41, Alexey Kardashevskiy wrote: > On 08/27/2013 05:02 PM, Paolo Bonzini wrote: >> Il 27/08/2013 08:37, Alexey Kardashevskiy ha scritto: >>>>> So this is here to make sure we don't accidentally get out of halted >>>>> state by an interrupt on that vcpu. Could you please somehow make that >>>>> part obvious? Either by adding a comment or by only explicitly masking >>>>> DEC and EE and a comment :). >>>>> >>>>>> + cs->exit_request = 1; >>>>> >>>>> This should probably be qemu_cpu_kick_self(). >>>> >>>> Uh, no, I don't think so. This is there purely to make sure we exit >>>> the inner loop, and actually test cpu_can_run() which will test >>>> halted. AFAICT qemu_cpu_kick_self() won't do anything similar. >>> >>> rtas_stop_self() eventually returns to kvm_cpu_exec() which calls >>> qemu_cpu_kick_self() and resets cs->exit_request before return so I do not >>> really see the difference in behaviour. And actually both ways CPU stops in >>> exactly the same way. What do I miss? >> >> What about TCG? > > Oh. Right. TCG :( > > qemu_cpu_kick_self() crashes the guest and cs->exit_request works fine. > > Why? Both should work? What is the expected behavior here? Thanks.
Hrm. To me exit_request always was an internal piece of state that the inner loop uses to find out whether to exit, but not something we should randomly set from a device (and hypercalls / rtas calls are very similar to devices). So I would like to not have any code in hw/ that modifies it. However, we need the functionality of breaking out of the main loop, I agree. Maybe what you are really looking for is cpu_interrupt(CPU_INTERRUPT_HALT). That sets halted = 1 and exits the main loop, because it's an interrupt. Alex
