Re: [Qemu-devel] [PATCH] allow setting static devfn values for pci devices from the command line

[Izik Eidus <izike@qumranet.com>]

Jocelyn Mayer wrote:
> On Mon, 2007-11-19 at 18:53 +0200, Izik Eidus wrote:
>   
>> Izik Eidus wrote:
>>     
>>> hi,
>>> this patch make it possible to define from the command line a static 
>>> devfn value for each pci
>>> device.
>>> it was wrote for addressing a problem that right now qemu devices get 
>>> their devfn in random way
>>> (almost random)
>>> the problem with this is that with adding and removing devices some 
>>> devfn values can be changed
>>> for each device.
>>> this make (at least) windows unable to understand what happned to your 
>>> device and mark it
>>> in yellow color. (and will want you to reinstall it)
>>>
>>> in this patch i simply use the device name that was registred with the 
>>> pci device registration
>>> function.
>>> in case you have few devices from the same type (same name), it will 
>>> simply increase each by one
>>> so in this case all you have to do is give long enough  offset for the 
>>> devfns from each other.
>>>
>>> thanks
>>>       
>> ok here is a fix to two issues that i noticed:
>> 1.in one place i declared static_devfns[MAX_PCI_DEVICS][64] and in other 
>> place: static_devfns[MAX_PCI_DEVICS][128]
>>
>> 2.in one place i did a calculation on a pointer line before i checked if 
>> it is vaild pointer...
>>
>> anyway here it is again and fixed.
>>     
>
> It seems that you cannot impose the PCI device numbers mapping, which is
> likely to be architecture dependant. What you could however change is
> the PCI bus & slot the device is inserted into, the same way you can
> choose the PCI slot you put a PCI card into on a real machine. The
> architecture could then determine what is the corresponding PCI device
> number, given this PCI bus & slot numbers.
i will check this.
> For other PCI devices, like PCI bridges or other internal devices, the
> PCI slots / devfn are fixed by the architecture. You cannot change them
> in any way, then it seems pointless to have an option that would change
> the behavior for any of those devices.
> The last problem I see is that it seems very ugly to hardcode the device
> names the way you did in vl.c. This is even false in most cases, as most
> of those devices are only available for a few machines and are not
> tunable at all (for example macio or uninorth are only available in some
> Apple Mac machines, not even all). 
>   
so how will i inform the user with the devices name?