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

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

On Tuesday 24 February 2009 20:07:16 Frank van der Linden 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.
>
> > For DomU translation of the address is needed, that's correct.
> > For Dom0 logging physical is good because the logging tools
> > might need that.
>
> Right. As far as I understand it, this patch proposes to deliver the
> actual physical information to dom0 via the existing vIRQ mechanism,
> while the vMCE mechanism delivers virtualized info to any guest (both
> dom0 and domU).

The translation is still problematic: What if an error occured which impacts
multiple physical contigous pages ? Translated into guest-physical
address space, they may be non-contigous.

That's why the original design does not support HVM guests unless they
are aware about running in Xen via an PV machine check driver.

Christoph

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