On Thu, Jul 31, 2014 at 06:36:35PM +0100, Peter Maydell wrote: > On 31 July 2014 18:21, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > What does ARM do if you have a WFI while interrupts are disabled? On > > x86 after "cli;hlt" only an NMI will wake you up. With spurious > > wakeups, it's pretty much guaranteed that you will break such "cli;hlt" > > sequences. > > The architecture mandates some things that *must* wake you from > a WFI, but it also allows wakeups for other reasons not listed, or > for no reason at all. It's perfectly valid to implement WFI as a NOP > (though it would not be very good for power efficiency, obviously). > Guests which don't surround WFI with a "check whether we should > just go back to WFI" loop are buggy. (and in case that wasn't clear, local_irq_disable() doesn't prevent an interrupt from waking you up from wfi, otherwise our idle code would be broken). Will -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
