Re: [Qemu-devel] [PATCH 5/8] timers: prepare the code for future races in calling qemu_clock_warp

[Paolo Bonzini]

Il 08/10/2013 18:54, Alex Bligh ha scritto:
>> > -
>> > -    /* Maintain prior (possibly buggy) behaviour where if no deadline
>> > -     * was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more 
>> > than
>> > -     * INT32_MAX nanoseconds ahead, we still use INT32_MAX
>> > -     * nanoseconds.
>> > -     */
>> > -    if ((deadline < 0) || (deadline > INT32_MAX)) {
>> > -        deadline = INT32_MAX;
>> > +    if (deadline < 0) {
>> > +        return;
>> >     }
> 
> Arguably the patch could document why removing the check for deadline > 
> INT32_MAX
> (the bug for bug compatibility) is safe, as I couldn't entirely convince 
> myself it
> was, mostly because I couldn't see why it was doing it in the first place.

I couldn't convince myself that it is _not_ safe :) and it made the code
more complicated.  As soon as a deadline appears, qemu_clock_warp() will
be called again and update the icount_warp_timer.

Ok to move that to a separate patch?

Paolo