Re: Re: [RFC] RAS(Part II)--MCA enalbing in XEN

[Christoph Egger <Christoph.Egger@amd.com>]

On Tuesday 24 February 2009 21:33:47 Kleen, Andi wrote:
> >Kleen, Andi wrote:
> >>> MCA information is highly specific to the hardware.
> >>
> >> Actually Intel has architectural machine checks and except for
> >> some optional addon information explicitely marked it's all
> >
> >architectural
> >
> >> (as in defined to stay the same going forward)
> >
> >True, I probably expressed myself poorly here. I meant to say: it's a
> >physical hardware error, and in an unmodified virtualized environment
> >the information about the physical hardware isn't there.
>
> In a DomU it's not important that the physical hardware is correctly
> described, the only thing that matters is that the event triggers
> the DomU code to do the expected action.

I agree with that. The DomU see's a hw environment which may
(partially) match the physical hardware. The physical machine check error
must be translated in a way that fits into the guest's hw environment.
This is not just limited to the memory layout.

An example to clarify the point
(which actually won't apply directly to Xen, but you should get the idea):

The guest hw environment is an (emulated) sparc CPU, memory
and PCI devices. The host's hw environment is a x86 PC. Now an
machine check error occurs. If you want to forward it into the guest,
you must translate it in a way as the guest OS would expect it from
a native sparc machine.


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