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

Anthony Liguori
2010-12-04T13:30:08Z

On 12/04/2010 02:13 AM, Avi Kivity wrote:
> On 12/04/2010 12:45 AM, Anthony Liguori wrote:
>>> hlt exiting doesn't leave vcpu in the halted state (since hlt has
>>> not been executed). So currently we never see a vcpu in halted state.
>>
>>
>> Right, you mean the guest activity state being halt.
>>
>> My understanding is that it just needs to be cleared on exception
>> injection. Would could clear it at every vmentry but that would
>> introduce a vmcs_read() to the fast path which is undesirable.
>
> Also need to skip the hlt instruction (by calling the emulator for
> example).

I wasn't sure about this. Don't you want EIP to point to the beginning
of the instruction such that the exception will cause the instruction to
restart?

Regards,

Anthony Liguori