Re: [PATCH] Add MCE support to KVM

[Gerd Hoffmann]

On 04/20/09 11:05, Avi Kivity wrote:
> Gerd Hoffmann wrote:
> > On 04/20/09 10:26, Avi Kivity wrote:
> > > Gerd Hoffmann wrote:
> > > > The xen pv-on-hvm drivers use an msr to indicate "please place the
> > > > hypercall page here". Handling that in kernel isn't an option IMHO.
> > >
> > > The contents of the hypercall page are vendor specific. This can be
> > > handled from userspace (though ideally we'd abstract the cpu vendor
> > > away).
> >
> > Well, xenner doesn't do vmcalls, so the page isn't vendor specific.
>
> Well, for true pv (not pv-on-hvm) it wouldn't use the MSR, would it?

Yes, the MSR is used for pv-on-hvm only.

> > It looks different for 32bit / 64bit guests though. And it actually
> > can be multiple pages (with one msr write per page). So the interface
> > for in-kernel handling would be more complex than "here is a hypercall
> > page for you".
>
> To different MSRs, or multiple writes to the same MSR?

Same MSR, multiple writes (page number in the low bits).

cheers,
  Gerd

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