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

[Avi Kivity <avi@redhat.com>]

On 05/19/2011 02:54 PM, Gleb Natapov wrote:
> >
> >  In this case the device would call a chipset function, passing the
> >  memory region as a parameter, and the chipset would call
> >  m_r_add_subregion().
> But then chipset can resolve all overlapping by itself and register only
> regions that are actually accessible by a guest software.

Sure it can (and it does now), but it's hard.  This API centralizes the 
logic, leaving the devices/chipsets to specify what they want.

For a PC, we have at least two such cases, the ISA bus and the PCI bus.

>   Also there are
> devices that on some architectures are accessed through a chipset and on
> other they resides directly on a system bus. If they will need to call
> different memory registration api depending on how they are instantiated
> the code can become messy.

An example is ne2000-isa and ne2000-pci.  There's no getting around some 
glue logic, but I think this API minimizes it (you can declare 
everything about your memory region in common code, the only thing that 
is different is registration).

-- 
error compiling committee.c: too many arguments to function