Re: [Xen-ia64-devel] psr.sp/is/di/si virtualization

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

On Tue, May 08, 2007 at 03:38:38PM +0200, Tristan Gingold wrote:

> these psr bits are not fully virtualized and the current usage is not
> clear (at least to me):
> 
> sp (secure performance monitor): I don't know how it is currently used by
>   xenoprofile.  Isaku have you any tips on it ?

The current xenoprofile model is that xen vmm controls pmc/pmd.
So xenoprof needs to prevent the guest os changing psr.up bit
(user pserfomance monitor enable) by setting pser.sp.

When considering pmc/pmd virtualization, the xenoprof requirement
should be revised. How the virtualization coexist with
xenoprof should be considered.


> di (disable instruction set transition): should it be hard-coded to 1 or
>  should it be settable by the kernel ?
> 
> si (secure interval timer): should be forced to 0?

Vanilla Linux/ia64 sets psr.si = 0 so that application can read it
without kernel intervention.
But I don't know how many application expect this fact.
Probably only benchmarking apps?


> is (instruction set): same use as di.
> 
> mc (machine check): should be forced to 1?

Or dom0 desires to change?

-- 
yamahata

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