On Thu, Sep 10, 2015 at 11:14:27AM +0800, Jason Wang wrote:
>
>
> On 09/08/2015 03:38 PM, Yuanhan Liu wrote:
> > So that we could use the `vq_index' as well in the vhost_net_init
> > stage, which is required when adding vhost-user multiple-queue support,
> > where we need the vq_index to indicate which queue pair we are gonna
> > initiate.
> >
> > vhost-user has no multiple queue support yet, hence no queue_index set
> > before. Here is a quick set to 0 at net_vhost_user_init() stage, and it
> > will be set properly soon in the next patch.
> >
> > Signed-off-by: Yuanhan Liu <yuanhan....@linux.intel.com>
> > ---
> > hw/net/vhost_net.c | 16 +++++++---------
> > net/vhost-user.c | 1 +
> > 2 files changed, 8 insertions(+), 9 deletions(-)
> >
> > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> > index f9441e9..141b557 100644
> > --- a/hw/net/vhost_net.c
> > +++ b/hw/net/vhost_net.c
> > @@ -138,6 +138,11 @@ static int vhost_net_get_fd(NetClientState *backend)
> > }
> > }
> >
> > +static void vhost_net_set_vq_index(struct vhost_net *net, int vq_index)
> > +{
> > + net->dev.vq_index = vq_index;
> > +}
> > +
> > struct vhost_net *vhost_net_init(VhostNetOptions *options)
> > {
> > int r;
> > @@ -167,6 +172,8 @@ struct vhost_net *vhost_net_init(VhostNetOptions
> > *options)
> > }
> > net->nc = options->net_backend;
> >
> > + vhost_net_set_vq_index(net, net->nc->queue_index * 2);
> > +
>
> This breaks vhost kernel multiqueue since queue_index was not
> initialized at this time.
Right, thanks for pointing it out.
> We do this in set_netdev() instead of setting
> it in each kind of netdev.
Can we move it to net_init_tap() for setting the right queue_index
for each nc?
Or, can we call vhost_net_set_vq_index twice, one at vhost_net_init(for
vhost-user mq support), another one at vhost_net_start(for vhost kernel
mq support)?
Or, do you have better ideas?
>
> > net->dev.nvqs = 2;
> > net->dev.vqs = net->vqs;
> >
> > @@ -196,11 +203,6 @@ fail:
> > return NULL;
> > }
> >
> > -static void vhost_net_set_vq_index(struct vhost_net *net, int vq_index)
> > -{
> > - net->dev.vq_index = vq_index;
> > -}
> > -
> > static int vhost_net_set_vnet_endian(VirtIODevice *dev, NetClientState
> > *peer,
> > bool set)
> > {
> > @@ -325,10 +327,6 @@ int vhost_net_start(VirtIODevice *dev, NetClientState
> > *ncs,
> > goto err;
> > }
> >
> > - for (i = 0; i < total_queues; i++) {
> > - vhost_net_set_vq_index(get_vhost_net(ncs[i].peer), i * 2);
> > - }
> > -
> > r = k->set_guest_notifiers(qbus->parent, total_queues * 2, true);
> > if (r < 0) {
> > error_report("Error binding guest notifier: %d", -r);
> > diff --git a/net/vhost-user.c b/net/vhost-user.c
> > index 93dcecd..2d6bbe5 100644
> > --- a/net/vhost-user.c
> > +++ b/net/vhost-user.c
> > @@ -146,6 +146,7 @@ static int net_vhost_user_init(NetClientState *peer,
> > const char *device,
> > /* We don't provide a receive callback */
> > s->nc.receive_disabled = 1;
> > s->chr = chr;
> > + nc->queue_index = 0;
> >
>
> Fail to understand why this is needed. It will be set to correct value
> in set_netdev().
Right, it's unnecessary.
BTW, May I ask you a quick question: why set_netdev is invoked after
tap init, while it is invoked before vhost-user init?
--yliu
>
> > qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);
> >
