Re: [Xen-devel] Re: pvclock in userland (reprise)

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

On 09/18/09 01:06, Keir Fraser wrote:
> On 18/09/2009 08:29, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:
>
>   
>>> I don't think mapping things into application address space is really
>>> possible without guest kernel changes. The guest kernel owns and manages the
>>> pte that you'd be overwriting. Just blatting the pte would not be good form.
>>>       
>> Unless they sit in Xen's virtual space.
>>     
> Oh yes, I remember we talked about that before. That is possible, but the
> design fell down on other points. I think guest kernel involvement, even if
> only as a kernel driver, should make this more tractable.
>   

Xen's memory isn't mappable in a 32-bit compat domain, so you'd need to
come up with something else there.  Does Xen still claim the top part of
the 32-bit address space?

    J

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