Re: [PATCH 7/8] KVM: Optimize kvm_read_cr[04]_bits()

Jan Kiszka
2010-02-07T13:20:27Z

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Avi Kivity wrote:
> On 02/07/2010 02:33 PM, Jan Kiszka wrote:
>> Avi Kivity wrote:
>>
>>> On 02/05/2010 10:26 AM, Jan Kiszka wrote:
>>>
>>>> Avi Kivity wrote:
>>>>
>>>>
>>>>> 'mask' is always a constant, so we can check whether it includes a
>>>>> bit that
>>>>> might be owned by the guest very cheaply, and avoid the decache
>>>>> call. Saves
>>>>> a few hundred bytes of module text.
>>>>>
>>>>>
>>>> -no-kvm-irqchip -smp 2 is broken for my Linux guests since this commit.
>>>> Their user space applications receive #UD and things fall apart.
>>>>
>>>>
>>>>
>>> Does 2c8232fc help?
>>>
>>>
>> Nope, unfortunately.
>>
>>
>
> Which specific guests exhibit the behaviour?
>

64-bit Linux, various kernels from 2.6.27 to 32. x86-32 appears to be
unaffected.

Jan

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