Re: [Qemu-devel] [PATCH 1/2] pci: Add pci_device_get_host_irq

[Jan Kiszka]

On 2012-05-30 21:30, Michael S. Tsirkin wrote:
> On Wed, May 30, 2012 at 09:06:25PM +0200, Jan Kiszka wrote:
>> On 2012-05-30 20:51, Michael S. Tsirkin wrote:
>>> On Wed, May 30, 2012 at 09:29:13PM +0300, Michael S. Tsirkin wrote:
>>>> On Wed, May 30, 2012 at 09:23:56PM +0300, Michael S. Tsirkin wrote:
>>>>> On Wed, May 30, 2012 at 07:57:04PM +0200, Jan Kiszka wrote:
>>>>>> On 2012-05-30 19:51, Jan Kiszka wrote:
>>>>>>>> Well, I'll stop ranting here.  The patch that I sent is not intrusive
>>>>>>>> and simply gives you a simple way to implement pci_device_get_host_irq,
>>>>>>>> also optimizing emulated devices somewhat.  So if you think you need
>>>>>>>> pci_device_get_host_irq I think this is a reasonable way to support
>>>>>>>> that.  But if you changed your mind, I don't mind.
>>>>>>>
>>>>>>> Sorry, your patch doesn't help me in any way.
>>>>>>
>>>>>> [to finish the sentence]
>>>>>>
>>>>>> ...as it doesn't handle the final routing step in the host bridge.
>>>>>
>>>>> I think you mean the logic in piix3_set_irq_level?
>>>>>
>>>>> True. I suggest we make piix3_set_irq_level use the map_irq
>>>>> infrastructure somehow:
>>>>
>>>> BTW, can't we simply override map_irq and make it read from
>>>> piix3->dev.config[PIIX_PIRQC + pirq]?
>>>
>>> Basically move
>>>     pic_irq = piix3->dev.config[PIIX_PIRQC + pirq];
>>> to pci_slot_get_pirq.
>>
>> map_irq might be reused, but not that easily as the return value is used
>> as irq_count index.
>>
>> Jan
> 
> So we'll just have PIIX_NUM_PIC_IRQS entries there and use
> irq_count instead of the pic_levels bitmap.

Just that this affects generic PCI code, not only PIIX-specific things.
And that we need to save/restore some irq_count field according to the
old semantics. As I said: not that easy. :)

Jan

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