Re: [PATCH 1/1] Disable GUEST_INTR_STATE_STI flag before injecting NMI to guest on VMX

[Jan Kiszka <jan.kiszka@siemens.com>]

Avi Kivity wrote:
>   On 08/27/2010 02:06 PM, Jan Kiszka wrote:
>>> Wow.  Maybe we should request an interrupt window instead when
>>> blocked-by-STI is active instead of clearing it.
>>>
>> Then we are (almost) back in pre-NMI-window times when the guest happens
>> to spin with IRQs disabled.
> 
> No.  We only request an interrupt window if we're blocked by STI.  That 
> implies that interrupts will be enabled by the next instruction.
> 
> (except if the code is sti; cli?)

Yes, we are only talking about weird use cases like the above or if the
guest decides to leave IRQs off on NMI return. So it is not as bad as
without any VNMI support.

> 
> Is there anything in x86 that doesn't suck?
> 

Hard to imagine.

Jan

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