Re: [Qemu-devel] [RFC] Memory API

[Avi Kivity <avi@redhat.com>]

On 05/22/2011 01:53 PM, Jan Kiszka wrote:
> On 2011-05-22 10:41, Gleb Natapov wrote:
> >>  The chipset knows about the priorities.  How to communicate them to
> >>  the core?
> >>
> >>  - at runtime, with hierarchical dispatch of ->read() and ->write():
> >>  slow, and doesn't work at all for RAM.
> >>  - using registration order: fragile
> >>  - using priorities
> >>
> >  - by resolving overlapping and registering flattened list with the core.
> >    (See example above).
>
> [Registration would happens with the help of the core against the next
> higher layer.]
>
> To do this, you need to
>   - open-code the resolution logic at every level (very bad idea)
>   - provide library services to obtain a flattened representation
>
> Please try to specify such an API without any parameters that are
> priority-like.

Another way of saying the same thing:  having the chipset code resolve 
conflicts, and having the chipset code assign priorities, are 
equivalent.  But having priorities allows flattening to take place 
without further involvement of the chipset code.

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