Re: [Qemu-devel] Re: [PATCH] pci: initialize header type register.

[Michael S. Tsirkin]

On Mon, Feb 08, 2010 at 06:37:41PM +0100, Gerd Hoffmann wrote:
> On 02/08/10 18:32, Michael S. Tsirkin wrote:
>> On Mon, Feb 08, 2010 at 06:24:57PM +0100, Gerd Hoffmann wrote:
>>> On 02/08/10 17:27, Michael S. Tsirkin wrote:
>>>> On Mon, Feb 08, 2010 at 12:14:11PM +0100, Gerd Hoffmann wrote:
>>>>> On 02/08/10 11:17, Michael S. Tsirkin wrote:
>>>>>> On Mon, Feb 08, 2010 at 03:41:47PM +0900, Isaku Yamahata wrote:
>>>>>>> initialize header type register in pci generic code.
>>>>>>>
>>>>>>> Cc: Blue Swirl<address@hidden>
>>>>>>> Cc: "Michael S. Tsirkin"<address@hidden>
>>>>>>> Signed-off-by: Isaku Yamahata<address@hidden>
>>>>>>
>>>>>> No objections here, I am assuming this will be followed
>>>>>> by patches removing header type init from bridges?
>>>>>>    From qdev perspective, it is probably cleaner to make
>>>>>> multifunction bit a separate qdev property though, right?
>>>>>
>>>>>    From a qdev perspective it would make *alot* of sense to move a bunch 
>>>>> of
>>>>> pci config stuff (including, but not limited to header type) into
>>>>> PCIDeviceInfo.
>>>>>
>>>>> cheers,
>>>>>     Gerd
>>>>
>>>> Actually - won't this make it possible to create broken configurations
>>>> by tweaking properties from command-line?
>>>
>>> Not as property, as struct element in PCIDeviceInfo.  i.e.
>>>
>>> static PCIDeviceInfo e1000_info = {
>>>      [ stuff which is here right now ]
>>>      .vendor_id = PCI_VENDOR_ID_INTEL,
>>>      .device_id = E1000_DEVID,
>>>      .class     = PCI_CLASS_NETWORK_ETHERNET,
>>>      [ probably more stuff which makes sense ]
>>> }
>>>
>>> Then setup this in generic pci code instead of having each driver doing
>>> a bunch of pci_config_set_*() calls.
>>>
>>> cheers,
>>>    Gerd
>>
>> We still end up with class, vendor etc duplicated in 2 places.
>
> No.  The info should be *only* in PCIDeviceInfo then.

That would put a lot of code in pci config cycle path.  A single array
mirroring the whole config space is much cleaner.

>>  Why do
>> we want stuff like vendor id in PCIDeviceInfo at all?  Why can't
>> everyone just use pci_config_set/get calls?
>
> You can do nice stuff like printing vendor/device IDs in the '-device ?'  
> list then.

That should use pci functions as well.

> cheers,
>   Gerd