Re: [PATCH v1 1/2] qemu-timer: gracefully handle the end of time

[Paolo Bonzini <pbonzini@redhat.com>]

On 28/07/20 18:08, Alex Bennée wrote:
> 
> Paolo Bonzini <pbonzini@redhat.com> writes:
> 
>> On 28/07/20 16:10, Alex Bennée wrote:
>>> +    /*
>>> +     * Check to see if we have run out of time. Most of our time
>>> +     * sources are nanoseconds since epoch (some time around the fall
>>> +     * of Babylon 5, the start of the Enterprises five year mission
>>> +     * and just before the arrival of the great evil ~ 2262CE).
>>> +     * Although icount based time is ns since the start of emulation
>>> +     * it is able to skip forward if the device is sleeping (think IoT
>>> +     * device with a very long heartbeat). Either way we don't really
>>> +     * handle running out of time so lets catch it and report it here.
>>> +     */
>>> +    if (current_time == INT64_MAX) {
>>> +        qemu_handle_outa_time();
>>> +        goto out;
>>> +    }
>>> +
>>
>> Doing this here is a bit dangerous, I'd rather do nothing here and
>> detect the situation in cpus.c where we can do
>> qemu_system_shutdown_request() (and also do nothing).
> 
> You mean in notify_aio_contexts()? Sure we can do that.

Yes, that would work.  I think qemu_clock_deadline_ns_all would already
return -1 so that you'd have a zero-instruction budget from
tcg_get_icount_limit.

Paolo