Re: [PATCH 1/5] migration: Updated QAPI format for 'migrate' qemu monitor command

[Daniel P . Berrangé]

On Fri, Jan 13, 2023 at 01:37:26PM +0530, Het Gala wrote:
> 
> On 09/01/23 7:37 pm, Daniel P. Berrangé wrote:
> > On Mon, Dec 26, 2022 at 05:33:25AM +0000, Het Gala wrote:
> > > From: Author Het Gala <het.gala@nutanix.com>
> > > 
> > > Existing 'migrate' QAPI design enforces transport mechanism, ip address
> > > of destination interface and corresponding port number in the form
> > > of a unified string 'uri' parameter. This scheme does seem to have an 
> > > issue
> > > in it, i.e. double-level encoding of URIs.
> > > 
> > > The current patch maps existing QAPI design into a well-defined data
> > > structure - 'MigrateChannel' only from the design perspective. Please 
> > > note that
> > > the existing 'uri' parameter is kept untouched for backward compatibility.
> > > 
> > > +##
> > > +# @MigrateRdmaAddr:
> > > +#
> > > +# Since 8.0
> > > +##
> > > +{ 'struct': 'MigrateRdmaAddr',
> > > +   'data' : {'rdma-str': 'str' } }
> > Loooking at the RDMA code it takes the str, and treats it
> > as an IPv4 address:
> > 
> > 
> >          addr = g_new(InetSocketAddress, 1);
> >          if (!inet_parse(addr, host_port, NULL)) {
> >              rdma->port = atoi(addr->port);
> >              rdma->host = g_strdup(addr->host);
> >              rdma->host_port = g_strdup(host_port);
> >          }
> > 
> > so we really ought to accept an InetSocketAddress struct
> > directly
> > 
> >   { 'struct': 'MigrateRdmaAddr',
> >      'data' : {'rdma-str': 'InetSocketAddress' } }
> > 
> Hi Daniel. I was going through the rdma code, and I think we also need
> 'host_port' for rdma_return_path context
> https://github.com/qemu/qemu/commit/44bcfd45e9806c78d9d526d69b0590227d215a78.
> I dont have much understanding but If you have any suggestion or a
> workaround for this, please suggest :)

The return path calls back into qemu_rdma_data_init() which takes
host_port, but you'll already be changing that to take InetSocketAddress,
so that'll be fine.

With regards,
Daniel
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