On 09/27/2010 11:22 AM, Alexander Graf wrote:
On 27.09.2010, at 11:17, Avi Kivity wrote:
> On 09/27/2010 11:15 AM, Alexander Graf wrote:
>> >
>> > Wow, this is incredibly ugly :). Can't we just mask NMIs when the
interrupt shadow is active?
>
> I plan to do that, for all the code that's out there relying on on STI
interrupt shadow masking NMIs.
>
>> Yeah, that's me writing without thinking. So this means that the race can
also happen on real hardware?
>>
>
> Yes. At least on documented hardware. Some (most? all?) hardware does mask
NMIs after STI.
If all hardware masks NMIs after STI, wouldn't it be better to update the spec
and declare KVM buggy for injecting NMIs there?
I don't have write permissions for the spec. If you can verify that all
existing and future hardware will mask NMI after STI and convince the
spec owners to update the specifications, I'm all for it; it's certainly
a cleaner solution.
Note these days hardware includes virtual hardware; though it's less
affected. Missing a wakeup is critical for real time systems --
virtualized systems are unlikely to notice it unless they have exactly
one interrupt source.
--
error compiling committee.c: too many arguments to function
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