[libvirt] [PATCH 2/3] qemu: RDMA migration support using 'x-rdma' URI

[Michael R. Hines]

On 07/26/2013 02:56 PM, Eric Blake wrote:
> On 07/26/2013 12:48 PM, Michael R. Hines wrote:
>
>>>>        int ret = -1;
>>>>    +    if (qemuCaps->version >= MIN_X_RDMA_VERSION) {
>>>> +        virQEMUCapsSet(qemuCaps, QEMU_CAPS_MIGRATE_QEMU_X_RDMA);
>>>> +    }
>>>> +
>>>>        if (!(archstr = qemuMonitorGetTargetArch(mon)))
>>>>            return -1;
>>>>    
>>> This is wrong. First, you're adding this into a totally wrong place and
>>> second, we need a better detection which is not based on qemu version.
>> How would we detect without using the QEMU version?
> Call 'query-migrate-capabilities' as part of the one-time capability
> probing in qemu_capabilities.c; if [x-]rdma-pin-all is listed, then RDMA
> is supported and you set the qemuCaps bit.  There's also the matter of
> handshaking between source and dest - we can't enable it on the source
> unless the dest also supports rdma; there, the migration cookie should
> be handy to pass destination support of the qemuCaps bit back to the
> source, in time for the source to react.
>
Acknowledged.