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Re: [Xen-devel] [PATCH] Hypercalls from HVM guests

To: Steve Ofsthun <sofsthun@xxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Hypercalls from HVM guests
From: Hollis Blanchard <hollisb@xxxxxxxxxx>
Date: Mon, 24 Apr 2006 11:53:01 -0500
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On Sat, 2006-04-22 at 11:16 -0400, Steve Ofsthun wrote:
> >  3. On 64-bit, you may even want a separate 32-bit hypercall table 
> > containing wrappers that interface between 32-bit callers and the
> core 
> > 64-bit hypercall functions.
> At the moment, all of this can be dealt with in HVM DomU code.  By
> doing it
> there, we can avoid explicit parameter copying on every hypercall.
> The 32-bit
> vs. 64-bit hypercall interface variations are not unique to HVM code.
> Adding
> conversion interfaces in the hypervisor is only one solution to this
> problem.
> The interfaces themselves could be made size invariant.  Except for
> backward
> compatibility, the 32-bit interfaces could be made identical to the
> 64-bit
> interfaces using proper data typing and explicit data alignment. 

Sounds like a good idea to me... ;)

Hollis Blanchard
IBM Linux Technology Center

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