Re: [Qemu-devel] [PATCH 3/5] qdev/compat: virtio-blk-pci 0.10 compatibility.

[Michael S. Tsirkin]

On Thu, Jul 09, 2009 at 05:09:41PM +0200, Gerd Hoffmann wrote:
> On 07/09/09 16:52, Michael S. Tsirkin wrote:
>>>       .compat_props = (CompatProperty[]) {
>>> +        {
>>> +            .driver   = "virtio-blk-pci",
>>> +            .property = "class",
>>> +            .value    = "0x0180", /* PCI_CLASS_STORAGE_OTHER */
>>
>> it seems annoying that we can't use the symbolic name. Ideas how to fix this?
>
> We could add a special property type instead of using hex32.  Then we  
> can have a string <-> int mapping and use something like
>
>              .value = "storage-other",
>
> Not sure it is worth the trouble though.
>
>>> -
>>> -    uint16_t vendor;
>>> -    uint16_t device;
>>> -    uint16_t subvendor;
>>> -    uint16_t class_code;
>>> -    uint8_t pif;
>>
>> Are the other fields unused? If yes can be a separate patch ...
>
> Yes, they are all unused to date.  This patch puts class_code into use.
>
>>> +    if (proxy->class_code != PCI_CLASS_STORAGE_SCSI&&
>>> +        proxy->class_code != PCI_CLASS_STORAGE_OTHER)
>>> +        proxy->class_code = PCI_CLASS_STORAGE_SCSI;
>>> +
>>
>> what does this do?
>
> Make sure proxy->class_code has one of the two allowed values.
>
>>>       vdev = virtio_blk_init(&pci_dev->qdev);
>>>       virtio_init_pci(proxy, vdev,
>>>                       PCI_VENDOR_ID_REDHAT_QUMRANET,
>>>                       PCI_DEVICE_ID_VIRTIO_BLOCK,
>>> -                    PCI_CLASS_STORAGE_OTHER,
>>> -                    0x00);
>>> +                    proxy->class_code, 0x00);
>>>   }
>>>
>>>   static void virtio_console_init_pci(PCIDevice *pci_dev)
>>
>> does this mean that virtio block was broken by some previous
>> patch? It's not a good way to split changes: bisecting won't work.
>
> Huh?  virtio block wasn't broken.  What makes you think it was?
>
> cheers,
>   Gerd

This is adding a parameter to a function. Before this patch it was missing
this parameter so was broken?