Re: [Xen-ia64-devel] [patch 00/14] Kexec v20070912: Xen

[Tristan Gingold <tgingold@xxxxxxx>]

> > I'm happy to explore all avenues. Could you give me a little more
> > information on what you mean by reserving rids?
> 
> Note that I'm not sure this approach is possible or makes EFI/SAL/PAL
> happy. It might not work because I haven't given a deep consideration it.
> Presumably you know it better than me and others want to discuss on it.
> 
> Xen gives portion of usable rid to a guest, currently
> IA64_MIN_IMPL_RID_BITS=18 bits. And it reserves one portion for its
> own purpose (real mode emulation).
> It means that a guest can only see virtual address of given rids.
> and reserve rid for EFI 
> When we want to call EFI
>   - which the current rid to the rid for EFI
>   - call EFI
>     here tlb miss fault might occur, and we can distinguish the fault
>     caused by EFI call from guest domains by checking whether the current
>     rid is reserved for EFI.
>   - which back the previous rid
[ I suppose you mean 'switch' instead of 'which' ?]

IMHO, this works.  But this is also for PAL and SAL.
And PAL must be ITR-mapped.

Tristan.

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