[Xen-ia64-devel] RE: vcpu context merge

["Magenheimer, Dan (HP Labs Fort Collins)" <dan.magenheimer@xxxxxx>]

> Magenheimer, Dan (HP Labs Fort Collins) wrote:
> > 1) Can the shared page be mapped at a fixed or guest-requested
> >    virtual address for non-VTI guests?   Xen needs to guarantee
> Yes, I think they are mapped by guest TR. Actually this merge doesn't
> change the way PV guest map the shared page. Maybe the only 
> difference 
> is that this merge may introduce additional map for per VP VPD.

Just to make sure I understand:  I would like a PV guest to make
a hypercall to Xen early on (probably in head.S prior to interrupts
being enabled) that says:

Map the shared page at THIS virtual address.  (If an illegal virtual
address is passed, Xen can kill the domain.)

> I know it introduce additional effort to do this in PV, kevin 
> and I can help together 
> to make that happen if you need :)

If all the virtual registers are a fixed offset from THIS
virtual address (see xen-ia64.bkbits.net/xenlinux-ia64-2.6.11.bk
in include/asm-ia64/xen/processsor.h), then only the
offset constants need to change.  If you can provide me
those constants for the new shared page, that would be
very helpful.

Also, I noticed in some of the ctrl_if(?) code, some data
structure is assumed to be at a fixed offset (1024) from
the shared page.  Is this accounted for in your merged
data structure?

Thanks,
Dan

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