Re: [Qemu-devel] [RFC PATCH RDMA support v2: 4/6] initialize RDMA options when QEMU first runs on command-line

[Michael S. Tsirkin]

On Tue, Feb 19, 2013 at 09:42:45AM +0100, Paolo Bonzini wrote:
> Il 19/02/2013 07:00, Michael R. Hines ha scritto:
> > Yes, this is done at migration time (see functions "rdma_client_init"
> > and "rdma_server_prepare()")
> > 
> > To explain the host and port:
> > 
> > The separate host and port are used by the library "librdmacm". This
> > library performs a network translation between the IP address and a
> > unique infiniband user-level Port number and the physical interface that
> > has the RDMA capabilities. This library requires an IP address and port
> > bound specifically to the requested RDMA interface to work.
> > 
> > The patch does not assume that the network interface used for TCP
> > traffic will necessarily be the same as the interface used for RDMA
> > traffic.
> 
> Of course the best thing to do would be to have all traffic on the RDMA
> interface... :)
> 
> Paolo

You can't do this with infiniband, RDMA is only possible once the
connection is established.


> > Alternatively, this host and port could be specified using the QMP
> > "migrate" command, but this command already has the URI for the TCP side
> > of things reserved.
> > 
> > If you guys like, we could specify a *second* URI on the QMP command
> > line - we don't really have a preference.
> > 
> > Either way is fine........ whatever the consensus is.
> > 
> > - Michael
>