Re: [PATCH 3/3] KVM: x86: correct mwait and monitor emulation

Bandan Das
2014-06-18T17:33:44Z

Paolo Bonzini <pbonzini@redhat.com> writes:

> Il 18/06/2014 18:43, Bandan Das ha scritto:
>>> > mwait and monitor are currently handled as nop. Considering this behavior, they
>>> > should still be handled correctly, i.e., check execution conditions and generate
>>> > exceptions when required. mwait and monitor may also be executed in real-mode
>> Is this necessary ? They are NOPs and kvm prints that out (correctly so) to dmesg.
>> Implementing them correctly is a different thing, but adding extra checks for NOPs
>> just seems like adding extra cycles.
>
> Raising the correct exception is a good thing, though. The guest is
> going to busy wait anyway, it doesn't matter how fast it does that. :)

Thanks, makes sense. I was also thinking why to advertise it at all, but it's
probably more common than I think it is.

> Paolo
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