[libvirt] [PATCH] qemuDomainAttachDeviceLive: Check provided disk address

Michal Privoznik mprivozn at redhat.com
Tue Sep 29 15:03:07 UTC 2015

On 25.09.2015 14:45, Martin Kletzander wrote:
> On Fri, Sep 25, 2015 at 06:41:44AM -0400, John Ferlan wrote:
>> On 09/25/2015 05:38 AM, Michal Privoznik wrote:
>>> On 25.09.2015 11:36, Martin Kletzander wrote:
>>>> On Thu, Sep 24, 2015 at 05:43:08PM +0200, Michal Privoznik wrote:
>>>>> https://bugzilla.redhat.com/show_bug.cgi?id=1257844
>>>>> Imagine an user who is trying to attach a disk to a domain with
>>>>> the following XML:
>>>>>  <disk type='block' device='disk'>
>>>>>    <driver name='qemu' type='raw'/>
>>>>>    <source dev='/dev/sr0'/>
>>>>>    <target dev='vde' bus='virtio'/>
>>>>>    <address type='drive' controller='0' bus='0' target='0' unit='0'/>
>>>>>  </disk>
>>>>> The XML is obviously wrong. It's trying to attach a virtio disk
>>>>> onto non-PCI bus. We should forbid that.
>>>>> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>>>>> ---
>>>>> src/qemu/qemu_hotplug.c | 7 +++++++
>>>>> 1 file changed, 7 insertions(+)
>>>> How come this is not handled in qemuDomainAssignAddresses(), it
>>>> doesn't get called?  There's a check for exactly that in
>>>> qemuAssignDevicePCISlots().
>>> Exactly! qemuAssignDevicePCISlots() is called only in case of --config.
>> Seems to me this may be more of a generic problem - a user providing the
>> wrong address type for the type of device. I have a recollection of
> Yes, and since we have checks for those, it's confusing to me why
> would qemuAssignDevicePCISlots() be called only with --config.  Can we
> use that code which checks for more things already?  For example, the
> here-missing virtio-mmio.

Yes and no. qemuDomainAssignAddresses() expects to see vm->def which
already has the device attached. Moreover, it not only works over all
devices in the domain (filling in all the missing addresses), but
possibly creating new controllers too (e.g. plugging new pci bridges if
running out of addresses on a bus).

Does anybody have a bright idea how this can be fixed apart from obvious
one - breaking whole address assignment code into parts and reassembling
it back together again?


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