[libvirt] [PATCHv2] conf: log error when incorrect PCI root controller is added to domain

[Laine Stump]

On 04/27/2016 12:07 PM, Cole Robinson wrote:
> On 04/26/2016 04:49 PM, Laine Stump wrote:
>> libvirt may automatically add a pci-root or pcie-root controller to a
>> domain, depending on the arch/machinetype, and it hopefully always
>> makes the right decision about which to add (since in all cases these
>> controllers are an implicit part of the virtual machine).
>>
>> But it's always possible that someone will create a config that
>> explicitly supplies the wrong type of PCI controller for the selected
>> machinetype. In the past that would lead to an error later when
>> libvirt was trying to assign addresses to other devices, for example:
>>
>>    XML error: PCI bus is not compatible with the device at
>>    0000:00:02.0. Device requires a PCI Express slot, which is not
>>    provided by bus 0000:00
>>
>> (that's the error message that appears if you replace the pcie-root
>> controller in a Q35 domain with a pci-root controller).
>>
>> This patch adds a check at the same place that the implicit
>> controllers are added (to ensure that the same logic is used to check
>> which type of pci root is correct). If a pci controller with index='0'
>> is already present, we verify that it is of the model that we would
>> have otherwise added automatically; if not, an error is logged:
>>
>>    The PCI controller with index='0' must be " model='pcie-root' for
>>    this machine type, " but model='pci-root' was found instead.
>>
>> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1004602
>> ---
>>
> ACK, but not sure what the freeze policy is? You probably know better, so push
> if you think it's appropriate

The policy for this one is "the code has been this way for ~3 years and 
only one person has complained, so it can wait another 5 days" :-)

Thanks!