Re: [Xen-devel] [PATCH] Change spec of callback IRQ for PV-on-HVMonIA64

[Doi.Tsunehisa@xxxxxxxxxxxxxx]

Hi Kevin,

You (kevin.tian) said:
>>> The callback value is the one pending to vIRR, which should be same
>>> as the one that platform-pci driver binds to. I'm still not sure the exact
>>> difference here. It should be arch-independent. You have to draw
>>> agreement between two sides.
>>
>>  In the Linux-world, I agree it. But... In the other OS (like Windows),
>>we can get only hardware IRQ with its driver interface. Thus I propose
>>to change the spec of callback IRQ.
>> 
> 
> Callback IRQ is only meaningful for xen, and if in any case, your 
> evtchn_interrupt still hooks at vector (0x21), what does matter to 
> change callback irq?

  I am talking about the situation of other OS guest on xen. In the
OS, we can't get the vector with its driver interface, because the
guest OS might set own value as vector to the interrupt controller.

  I believe that callback irq is the interface between hypervisor and
guest OS, thus it has to be indepent from kind of guest OS. Therefore
we should not use the value which we can't get in any OS.

> En... seems you're talking about other OS which register evtchn_interrupt
>  at 0x9 instead of 0x21? If that's the case, how to differentiate?

  I think that the other OS register evtchn_interrupt at own vector
determined by itself for GSI(0x9).

Thanks,
- Tsunehisa Doi

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