Re: [Qemu-devel] PCI: how handle multifunction / compound devices best?

[Markus Armbruster]

Anthony Liguori <address@hidden> writes:

> On 07/01/2011 06:27 AM, Gerd Hoffmann wrote:
>>    Hi folks,
>>
>> I'm still looking for a sane way to handle multifunction pci devices,
>> specifically a EHCI USB controller with UHCI companion controllers.
>>
>> Here comes a small (incomplete[1]) two patch series to make the issue
>> more clear.  The first patch adds a function which creates all devices
>> with the properties set as needed.  The second patch adds a '-usb2'
>> switch to windup this in a user-friendly way.
>>
>> Adding a -usb2 switch sucks though.  I'd prefer to have some way to
>> create such devices via -device, but without asking the user to create
>> all functions individually on the command line, i.e. have something
>> along the lines of ...
>>
>>   qemu -device ich9-usb,slot=08
>
> This is the place where are current infrastructure pretty much stinks.
>
> The first problem is that the device factory interface should be
> involved with device addressing.  We really should have:
>
> qemu -device ich9-usb,id=uhci0 -set i440fx.slot[8]=uhci0
>
> The device doesn't care what it's PCI slot address is.

What exactly would such a split buy us?

-device is not a message to the device, it's a message to whatever makes
devices.  Therefore, the fact that we specify the device address with
-device doesn't mean we've artificially made the device to care for its
address.

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