On Tue, Sep 22, 2015 at 08:47:04AM -0600, Eric Blake wrote:
> On 09/18/2015 08:58 AM, Yuanhan Liu wrote:
> > From: Changchun Ouyang <changchun.ouy...@intel.com>
> >
> > Add a new message, VHOST_USER_SET_VRING_ENABLE, to enable or disable
> > a specific virt queue, which is similar to attach/detach queue for
> > tap device.
> >
> > virtio driver on guest doesn't have to use max virt queue pair, it
> > could enable any number of virt queue ranging from 1 to max virt
> > queue pair.
> >
> > Signed-off-by: Changchun Ouyang <changchun.ouy...@intel.com>
> > Signed-off-by: Yuanhan Liu <yuanhan....@linux.intel.com>
> > ---
> > docs/specs/vhost-user.txt | 12 +++++++++++-
> > hw/net/vhost_net.c | 18 ++++++++++++++++++
> > hw/net/virtio-net.c | 8 ++++++++
> > hw/virtio/vhost-user.c | 19 +++++++++++++++++++
> > include/hw/virtio/vhost-backend.h | 2 ++
> > include/net/vhost_net.h | 2 ++
> > 6 files changed, 60 insertions(+), 1 deletion(-)
> >
> > diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> > index cfc9d41..a5f1c31 100644
> > --- a/docs/specs/vhost-user.txt
> > +++ b/docs/specs/vhost-user.txt
> > @@ -148,7 +148,9 @@ VHOST_USER_GET_PROTOCOL_FEATURES. Master should stop
> > when the number of
> > requested queues is bigger than that.
> >
> > As all queues share one connection, the master uses a unique index for each
> > -queue in the sent message to identify a specified queue.
> > +queue in the sent message to identify a specified queue. One queue pairs
>
> s/pairs/pair/
Thanks.
>
> > +is enabled initially. More queues are enabled dynamically, by sending
> > +message VHOST_USER_SET_VRING_ENABLE.
> >
> > Message types
> > -------------
> > @@ -327,3 +329,11 @@ Message types
> > Query how many queues the backend supports. This request should be
> > sent only when VHOST_USER_PROTOCOL_F_MQ is set in quried protocol
> > features by VHOST_USER_GET_PROTOCOL_FEATURES.
> > +
> > + * VHOST_USER_SET_VRING_ENABLE
> > +
> > + Id: 18
> > + Equivalent ioctl: N/A
> > + Master payload: vring state description
> > +
> > + Signal slave to enable or disable corresponding vring.
>
> Does there need to be any QMP control to manually change a given queue,
> or is it all used under the hood with no need for management apps to
> care other than their initial request of max queues?
TBH, I don't know. As far as I know, there is only one queue pair will
be enabled by default, and it's user's job to enable (or disable) more
queue pairs, say, by ethtool:
# ethtool -L eth0 combined <queue pair number>
Which ends up sending the VHOST_USER_SET_VRING_ENABLE to actually enable
(or disable) a specific queue pairs.
Does that answer your question?
--yliu
