Re: [Qemu-devel] device assignment for embedded Power

[Alexander Graf]

On 01.07.2011, at 13:55, Paul Brook wrote:

> 
>> But the real challenge is how to expose the device to the guest device
>> tree. Especially when it comes to links between dt nodes, interrupt maps,
>> etc. We basically have 3 choices there:
>> 
>>  * take the host device tree pieces and modify them
>>  * provide device tree chunks for each device (manually or through qdev
>> parameters) * use the device tree as machine config file and base
>> everything on it (solves the linking problem)
>> 
>> The main question is which one would be the cleanest solution. And how
>> would it be implemented.
> 
> I don't think any of this is specific to device passthrough.  It occurs as 
> soon as you have any user-configurable parts of the machine (or even just a 
> nontrivial selection of machine variants).  My guess is the only reason you 
> haven't hit it before is because you're only emulated a single hard-coded 
> SoC/board.

Well, the real reason we haven't hit this before is that we don't have any 
devices in Qemu that are generic. We only have specific device emulation. This 
however would be a device that can handle hundreds of different backing 
devices, all with different requirements.

The infrastructure we have today simply isn't made for this. The question is 
how can we model it so that it will? :)


Alex