Re: [PATCH v2 1/2] xen-pciback: redo VF placement in the virtual topology

[Jan Beulich <jbeulich@xxxxxxxx>]

On 20.05.2021 02:36, Boris Ostrovsky wrote:
> 
> On 5/18/21 12:13 PM, Jan Beulich wrote:
>>  
>> @@ -95,22 +95,25 @@ static int __xen_pcibk_add_pci_dev(struc
>>  
>>      /*
>>       * Keep multi-function devices together on the virtual PCI bus, except
>> -     * virtual functions.
>> +     * that we want to keep virtual functions at func 0 on their own. They
>> +     * aren't multi-function devices and hence their presence at func 0
>> +     * may cause guests to not scan the other functions.
> 
> 
> So your reading of the original commit is that whatever the issue it was, 
> only function zero was causing the problem? In other words, you are not 
> concerned that pci_scan_slot() may now look at function 1 and skip all 
> higher-numbered function (assuming the problem is still there)?

I'm not sure I understand the question: Whether to look at higher numbered
slots is a function of slot 0's multi-function bit alone, aiui. IOW if
slot 1 is being looked at in the first place, slots 2-7 should also be
looked at.

Jan