Re: [Xen-devel] Re: [RFC PATCH 03/35] Add Xen interface header files

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 9 May 2006, at 20:48, Anthony Liguori wrote:

> Is this strictly true though?  The ABI for Power and x86 are not 
> necessarily dependent on each other.  One could just as easily define 
> a typedef like:
> #if defined(__ppc__)
> typedef uint64_t guest_handle_t;
> #elif defined(__x86__)
> typedef unsigned long guest_handle_t;
> #endif
>
> I thought the use of GUEST_HANDLE was to maintain type safety.  It 
> certainly helps the issue you point out but it's not strictly 
> necessary.
> IMHO, this trick makes the code pretty ugly.  I'd rather see it 
> disappear in favor of something more akin to the above.
Well, I originally thought it was to allow hiding of machine-address 
scatter-gather lists for PPC (instead of passing virtual addresses). I 
seem to recall that's what Hollis said at the time. Clearly hiding 
something like that does need some macro magic. If it's not for that 
then I'm not at all for keeping it. It is indeed rather fugly.
 -- Keir


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