Re: [Qemu-devel] [PATCH 1/5] Add target memory mapping API

[Avi Kivity]

Anthony Liguori wrote:
> Paul Brook wrote:
> > It looks like what you're actually doing is pushing the bounce buffer 
> > allocation into the individual packet consumers.
> >
> > Maybe a solution to this is a 'do IO on IOVEC' actor, with an 
> > additional flag that says whether it is acceptable to split the 
> > allocation. That way both block and packet interfaces use the same 
> > API, and avoids proliferation of manual bounce buffers in packet 
> > devices.
> >   
>
> I think there may be utility in having packet devices provide the 
> bounce buffers, in which case, you could probably unique both into a 
> single function with a flag.  But why not just have two separate 
> functions?
>
> Those two functions can live in exec.c too.  The nice thing about 
> using map() is that it's easily overriden and chained.  So what I'm 
> proposing.
>
> cpu_physical_memory_map()
> cpu_physical_memory_unmap()

This should be the baseline API with the rest using it.

> do_streaming_IO(map, unmap, ioworker, opaque);

Why pass map and unmap?

grant based devices needn't go through this at all, since you never mix 
grants and physical addresses, and since grants never need bouncing.

> do_packet_IO(map, unmap, buffer, size, ioworker, opaque);

If you pass the buffer then the device needs to allocate large amounts 
of bounce memory.


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error compiling committee.c: too many arguments to function