Re: [Xen-devel] Grant Table Hyper Calls For Sharing Memory

[Daniel Stodden <stodden@xxxxxxxxxx>]

Hope I'm not mistaken, but I believe this discussion only revolves
around the fact that you don't need hypercalls to *share* pages. The
gnttab hypercall interface is only needed to *map* shared pages, not to
let other domains access a hvm's memory.

Sharing a page only requires the owner to set appropriate permissions in
her own grant table. That's just a bit of store and cmpxchg. No
hypercalling involved.

Cheers,
Daniel

On Wed, 2008-08-20 at 14:03 +0800, Kumar, Venkat wrote:
> I was following an email chain in the xen mailing list on HVM
> hypercalls on grant tables and the email chain link is below
> 
> http://lists.xensource.com/archives/html/xen-devel/2007-03/msg00688.html
> 
>  
> 
> This link says that we need not required hypercalls to share memory
> b/w HVMâs.
> 
>  
> 
> But as far as my understanding of sharing memory is concerned, I think
> the memory is shared using grant table mechanism and we would need
> Hypercall support related to grant tables to make this possible.
> 
>  
> 
> Correct me if I am wrong.
> 
>  
> 
> Or is there any other way of sharing memory or Inter domain
> communication?
> 
>  
> 
> Thx,
> 
> Venkat
> 
> ================================
> 
> Venkata Kumar Duvvuru,
> 
> LSI Engenio,
> 
> Adv. Development,
> 
> Bangalore.
> 
> Mob: +91-9880318542
> 
> Off : +91-80-41978700 ( Extn : 3544 )
> 
> ================================
> 
> 
>  
> 
> 
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-- 
Daniel Stodden
LRR     -      Lehrstuhl fÃr Rechnertechnik und Rechnerorganisation
Institut fÃr Informatik der TU MÃnchen             D-85748 Garching
http://www.lrr.in.tum.de/~stodden         mailto:stodden@xxxxxxxxxx
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