[libvirt] [PATCH 6/8] domain: Make <address type='pci'/> request address allocation

Laine Stump laine at laine.org
Tue Mar 22 15:43:29 UTC 2016


On 03/21/2016 02:59 PM, Cole Robinson wrote:
> On 03/21/2016 02:44 PM, John Ferlan wrote:
>
>> Would this be useful if "multifunction='on'" without specifying an
>> address? e.g.:
>>
>>      <address type='pci' multifunction='on'>
>>
> Maybe? Honestly I don't know much about when multifunction should be used.

I doubt that would ever be useful, since you need to match the multiple 
devices that are plugged into the slot by specifying a matching 
bus/slot, (the function# must always be 0 for the device that has 
"multifunction" option specified - it is supposed to be turned on for 
function 0 on any slot that has multiple functions in use. It seems to 
me that multifunction could have been left out of libvirt's XML 
completely, with 100% success of automatically turning it on at the 
correct time (since you *always* know ahead of time whether or not there 
will be multiple functions for a slot  - hotplugging of multiple 
functions into a slot isn't supported, and in the eventuality that we do 
support it, it will only be supported by plugging in all the functions 
at once.) Several years too late for that now though :-P )




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