Re: [Xen-ia64-devel] Protection key support for PV domains

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

On Fri, Jul 20, 2007 at 03:21:56PM +0200, Dietmar Hahn wrote:
> Hi,

Hi.


> Can I replace pkrs[8];tmp[8]; with pkrs[16] to use this for protection keys 
> or 
> should I expand pkrs and leave tmp[8] untouched. How about changing the 
> layout - is this possible here?

Given that xen/ia64 haven't keep the ABI compatibility (Yes, we have
changed the layout sometimes breaking the compatigbility), it would be
acceptable to change the layout, I suppose.


> In addition I would use a define for the number of pkrs. The only way to get 
> this is define it in arch-ia64.h for use from vmm and domU. Is this OK or is 
> there another solution possible?

Probably it would be OK because I don't suppose that the number will
be increased so frequently. Correct?


> Btw. I'll use Isaku's suggestion and will add a new hypercall to let vmm 
> setup 
> the cpu-pkrs with the values the domU changed.

Please note that I only read your patch and I haven't even tested your patch.
I'm not sure how you use pkrs.
The design decision should depend on its usage model.

-- 
yamahata

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