Re: [PATCH] kvm-vmx: add module parameter to avoid trapping HLT instructions (v2)

Anthony Liguori
2010-12-06T15:07:09Z

On 12/06/2010 08:33 AM, Avi Kivity wrote:
> On 12/06/2010 04:03 PM, Anthony Liguori wrote:
>>> It does. Good, it simplifies the patch.
>>
>>
>> Any ideas if the unit test framework can be used to validate this?
>> The behavior makes perfect sense but I wanted an excuse to play
>> around with it :-)
>>
>
> Not the user space one. The exit we're interested in is external
> interrupt, and that one isn't delivered to userspace.
>
> I guess you could have a loop
>
> 1: hlt
> jmp 1b
>
> and enter it programming a timer to something close, and examine the
> vcpu state afterwards. However you don't propagate the VMCS halted
> state to the corresponding kvm state, so there's no way to test it. (a
> minor bug in your patch)

The activity state doesn't get propagated at all to the kvm state. Can
we get into a non-zero activity state today (either SHUTDOWN or WAIT_SIPI)?

Regards,

Anthony Liguori

>> Not sure if there's a way to validate VMCS state after a hand crafted
>> exit.
>>
>
> KVM_GET_REGS and friends.
>
>
>