Messages in this thread | | | From | Peter Maydell <> | Date | Thu, 31 Jul 2014 18:36:35 +0100 | Subject | Re: [PATCH] arm64: KVM: export current vcpu->pause state via pseudo regs |
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On 31 July 2014 18:21, Paolo Bonzini <pbonzini@redhat.com> 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.
thanks -- PMM
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