* Maxime Coquelin (maxime.coque...@redhat.com) wrote:
>
>
> On 06/28/2017 09:00 PM, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
> >
> > This message is sent just before the end of postcopy to get the
> > client to stop using userfault since we wont respond to any more
> > requests. It should close userfaultfd so that any other pages
> > get mapped to the backing file automatically by the kernel, since
> > at this point we know we've received everything.
> >
> > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> > ---
> > contrib/libvhost-user/libvhost-user.c | 23 +++++++++++++++++++++++
> > contrib/libvhost-user/libvhost-user.h | 1 +
> > hw/virtio/vhost-user.c | 1 +
> > 3 files changed, 25 insertions(+)
> >
> > diff --git a/contrib/libvhost-user/libvhost-user.c
> > b/contrib/libvhost-user/libvhost-user.c
> > index d37052b7b0..c1716d1a62 100644
> > --- a/contrib/libvhost-user/libvhost-user.c
> > +++ b/contrib/libvhost-user/libvhost-user.c
> > @@ -68,6 +68,7 @@ vu_request_to_string(int req)
> > REQ(VHOST_USER_INPUT_GET_CONFIG),
> > REQ(VHOST_USER_POSTCOPY_ADVISE),
> > REQ(VHOST_USER_POSTCOPY_LISTEN),
> > + REQ(VHOST_USER_POSTCOPY_END),
> > REQ(VHOST_USER_MAX),
> > };
> > #undef REQ
> > @@ -889,6 +890,26 @@ vu_set_postcopy_listen(VuDev *dev, VhostUserMsg *vmsg)
> > return false;
> > }
> > +
> > +static bool
> > +vu_set_postcopy_end(VuDev *dev, VhostUserMsg *vmsg)
> > +{
> > + fprintf(stderr, "%s: Entry\n", __func__);
> > + dev->postcopy_listening = false;
> > + if (dev->postcopy_ufd > 0) {
> > + close(dev->postcopy_ufd);
> > + dev->postcopy_ufd = -1;
> > + fprintf(stderr, "%s: Done close\n", __func__);
> > + }
> > +
> > + vmsg->fd_num = 0;
> > + vmsg->payload.u64 = 0;
> > + vmsg->size = sizeof(vmsg->payload.u64);
> > + vmsg->flags = VHOST_USER_VERSION | VHOST_USER_REPLY_MASK;
> > + fprintf(stderr, "%s: exit\n", __func__);
> > + return true;
> > +}
> > +
>
> It is what reply-ack is done for, so to avoid code duplication,
> maybe Qemu could set VHOST_USER_NEED_REPLY_MASK bit when reply-ack
> feature is supported.
>
> I'm wondering if we shouldn't consider adding reply-ack feature support
> to libvhost-user, and make postcopy support to depend on this feature.
Yes, that would make sense; for the moment I'm adding what I think is
the same replies in the places I need ack's, and setting the
VHOST_USER_NEED_REPLY_MASK
so for the messages where I need it the semantics should be the same as
that.
Dave
> Cheers,
> Maxime
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
