[libvirt] [PATCH 4/4] qemu_capabilities: Temporarily disable dbus-vmstate capability

[Michal Privoznik]

On 9/6/19 5:55 PM, Ján Tomko wrote:
> [cc-ing Marc-André]
> 
> On Fri, Sep 06, 2019 at 04:25:19PM +0200, Michal Privoznik wrote:
>> The qemu side is not merged in yet, so there is a chance that the
>> interface will change. Don't detect the capability just yet then.
>>
>> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>> ---
>> src/qemu/qemu_capabilities.c | 1 -
>> 1 file changed, 1 deletion(-)
>>
>> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
>> index 136999ad0d..7be026ae12 100644
>> --- a/src/qemu/qemu_capabilities.c
>> +++ b/src/qemu/qemu_capabilities.c
>> @@ -1129,7 +1129,6 @@ struct virQEMUCapsStringFlags 
>> virQEMUCapsObjectTypes[] = {
>>     { "virtio-serial-pci-non-transitional", 
>> QEMU_CAPS_VIRTIO_PCI_TRANSITIONAL },
>>     { "max-x86_64-cpu", QEMU_CAPS_X86_MAX_CPU },
>>     { "bochs-display", QEMU_CAPS_DEVICE_BOCHS_DISPLAY },
>> -    { "dbus-vmstate", QEMU_CAPS_DBUS_VMSTATE },
>> };
>>
>> static struct virQEMUCapsStringFlags 
>> virQEMUCapsDevicePropsVirtioBalloon[] = {
> 
> If
> 1) dbus-vmstate is required for migration of a domain using a 
> slirp-helper and
> 2) we enable this automatically for existing XML configs with
>   <interface type='user'/> if
>   a) QEMU has QEMU_CAPS_NET_SOCKET_DGRAM
>   b) the slirp-helper process is installed on the system
> then we've effectively made their machines unmigratable
> 
> So if we want to enable it automatically, we should add:
> c) QEMU has QEMU_CAPS_DBUS_VMSTATE
> regardless of whether dbus-vmstate gets merged into QEMU until libvirt's
> next release

So are you saying that we should just temporarily revert 
QEMU_CAPS_NET_SOCKET_DGRAM detection instead and leave 
QEMU_CAPS_DBUS_VMSTATE be?

Michal