Re: [Xen-devel] [Question] About the behavior of HLT in VMX guest mode

["Longpeng (Mike)" <longpeng2@xxxxxxxxxx>]

Hi Jan,

On 2017/3/13 19:38, Jan Beulich wrote:

>>>> On 13.03.17 at 06:12, <longpeng2@xxxxxxxxxx> wrote:
>> I'm confusing about the behavior of HLT instruction in VMX guest mode.
>>
>> I set "hlt exiting" bit to 0 in VMCS, and the vcpu didn't vmexit when execute
>> HLT as expected. However, I used powertop/cpupower on host to watch the 
>> pcpu's
>> c-states, it seems that the pcpu didn't enter C1/C1E state during this 
>> period.
> 
> I guess no-one expects a VMM to want to set this control to zero,


Yep, I agree. I just do this for special purpose.

> so the behavior may well be unspecified or model-specific. Neither

> of which I'm in the position to comment on, so I can only defer to
> the Intel guys.


Thanks. :)

> 
> Jan
> 
> 
> .
> 


-- 
Regards,
Longpeng(Mike)


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