Re: [PATCH 2/2] migration: add vsock as data channel support

[Longpeng (Mike, Cloud Infrastructure Service Product Dept.)]

在 2020/8/12 17:52, Dr. David Alan Gilbert 写道:
> * Longpeng(Mike) (longpeng2@huawei.com) wrote:
> > The vsock channel is more widely use in some new features, for example,
> > the Nitro/Enclave. It can also be used as the migration channel.
> >
> > Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
>
> OK; it might be worth adding some tests for this.
OK, I'll try when I'm free.

> Can I ask what your use case is - is this migrating an L2 inside an L1
> or what?
Yes, L2 migrationg is a potential use case for this. However, our use 
case is still focusing on the L1 migration.

There is no network stack in our platform ( [1] ), so we use the vsock 
channel to communicate between the QEMU (on x86/ARM) and an Agent (on a 
PCIe card), the source Agent will transport the data to the destination.

Links:
[1] 
https://kvmforum2019.sched.com/event/Tmzh/zero-next-generation-virtualization-platform-for-huawei-cloud-jinsong-liu-zhichao-huang-huawei

> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Thanks.

> > ---
> >   migration/migration.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/migration/migration.c b/migration/migration.c
> > index 3160b95..fcf7974 100644
> > --- a/migration/migration.c
> > +++ b/migration/migration.c
> > @@ -383,7 +383,8 @@ void qemu_start_incoming_migration(const char *uri, Error 
> > **errp)
> >       if (!strcmp(uri, "defer")) {
> >           deferred_incoming_migration(errp);
> >       } else if (strstart(uri, "tcp:", &p) ||
> > -               strstart(uri, "unix:", NULL)) {
> > +               strstart(uri, "unix:", NULL) ||
> > +               strstart(uri, "vsock:", NULL)) {
> >           socket_start_incoming_migration(p ? p : uri, errp);
> >   #ifdef CONFIG_RDMA
> >       } else if (strstart(uri, "rdma:", &p)) {
> > @@ -2072,7 +2073,8 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
> >       }
> >   
> >       if (strstart(uri, "tcp:", &p) ||
> > -        strstart(uri, "unix:", NULL)) {
> > +        strstart(uri, "unix:", NULL) ||
> > +        strstart(uri, "vsock:", NULL)) {
> >           socket_start_outgoing_migration(s, p ? p : uri, &local_err);
> >   #ifdef CONFIG_RDMA
> >       } else if (strstart(uri, "rdma:", &p)) {
> > --
> > 1.8.3.1