Re: [Qemu-devel] Managing architectural restrictions with -device and libvirt

[Mark Cave-Ayland]

On 06/07/17 15:36, Markus Armbruster wrote:

>>>> I see two ways to continue:
>>>>   1. A new kind of pci-bridge should be created with a "special"
>>>>      secondary bus that has less slots. (harder to implement)
>>>>   2. Add the limitation of the number of slots to the PCIBus class,
>>>>      (simpler to implement, but since is not a widely used case maybe
>>>>      is not the best way to go.
>>>
>>> I suspect (2) would be trivial.  I like trivial.
>>
>> I also like trivial, what might not be trivial is to convince Michael
>> a base PCIBus class needs a property that limits the number of slots.
>> But since the device registration code is generic, we may need that
>> property anyway.
>>
>> Taking the idea a little farther, instead of limiting the slots number,
>> we can have a slot-available flag for each slot. In this way we can
>> cover more future requirements like "slot #5 is not never used".
> 
> That's strictly more general, and should still be trivial.

Indeed, having a bitmask is exactly what I suggested at the end of my
last email. I've quickly put something together which I'll send along
shortly...


ATB,

Mark.