Re: [Qemu-devel] [RFC] 64 bit device I/O

[Avi Kivity <avi@redhat.com>]

Robert Reif wrote:
> Blue Swirl wrote:
>> Would it be better to use a structure with four elements with correct
>> types (including uint8/16_t)  instead of the cast? This could also be
>> limited to only cpu_register_io_memory64.
>>
>>
>>   
> This is what I would prefer and is what the first version of this patch
> that I submitted a year ago did:   
> http://landley.net/qemu/2008-01-01.html
>
> The problem is that every hardware driver would need to be changed and
> some of them would need to be changed drastically because they use the
> same functions for all three data sizes.  No one seemed interested in 
> this
> approach so I abandoned it.
>
> This approach while uglier requires no changes to the hardware drivers
> unless they need 64 bit support so I hoped it would be better received.

You might try adding a struct-based 4-function interface, and 
implementing the array-based 3-function interface on top of that.  This 
way, no immediate changes would be needed for devices, but we could 
change them incrementally from the old interface to the new interface.


-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.