Re: [PATCH v2 18/19] vdpa: Add device migration blocker

[Jason Wang]

On Fri, Jul 15, 2022 at 1:40 PM Eugenio Perez Martin
<eperezma@redhat.com> wrote:
>
> On Fri, Jul 15, 2022 at 6:03 AM Jason Wang <jasowang@redhat.com> wrote:
> >
> > On Fri, Jul 15, 2022 at 12:32 AM Eugenio Pérez <eperezma@redhat.com> wrote:
> > >
> > > Since the vhost-vdpa device is exposing _F_LOG,
> >
> > I may miss something but I think it doesn't?
> >
>
> It's at vhost_vdpa_get_features. As long as SVQ is enabled, it's
> exposing VHOST_F_LOG_ALL.

Ok, so this needs to be specified in the change log. But I'm kind of
confused here, we do want to allow migration to work so why we disable
it?

Thanks

>
> Thanks!
>
> > Note that the features were fetched from the vDPA parent.
> >
> > Thanks
> >
> > > adding a migration blocker if
> > > it uses CVQ.
> > >
> > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > > ---
> > >  include/hw/virtio/vhost-vdpa.h |  1 +
> > >  hw/virtio/vhost-vdpa.c         | 14 ++++++++++++++
> > >  2 files changed, 15 insertions(+)
> > >
> > > diff --git a/include/hw/virtio/vhost-vdpa.h 
> > > b/include/hw/virtio/vhost-vdpa.h
> > > index 1111d85643..d10a89303e 100644
> > > --- a/include/hw/virtio/vhost-vdpa.h
> > > +++ b/include/hw/virtio/vhost-vdpa.h
> > > @@ -35,6 +35,7 @@ typedef struct vhost_vdpa {
> > >      bool shadow_vqs_enabled;
> > >      /* IOVA mapping used by the Shadow Virtqueue */
> > >      VhostIOVATree *iova_tree;
> > > +    Error *migration_blocker;
> > >      GPtrArray *shadow_vqs;
> > >      const VhostShadowVirtqueueOps *shadow_vq_ops;
> > >      void *shadow_vq_ops_opaque;
> > > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> > > index beaaa7049a..795ed5a049 100644
> > > --- a/hw/virtio/vhost-vdpa.c
> > > +++ b/hw/virtio/vhost-vdpa.c
> > > @@ -20,6 +20,7 @@
> > >  #include "hw/virtio/vhost-shadow-virtqueue.h"
> > >  #include "hw/virtio/vhost-vdpa.h"
> > >  #include "exec/address-spaces.h"
> > > +#include "migration/blocker.h"
> > >  #include "qemu/cutils.h"
> > >  #include "qemu/main-loop.h"
> > >  #include "cpu.h"
> > > @@ -1022,6 +1023,13 @@ static bool vhost_vdpa_svqs_start(struct vhost_dev 
> > > *dev)
> > >          return true;
> > >      }
> > >
> > > +    if (v->migration_blocker) {
> > > +        int r = migrate_add_blocker(v->migration_blocker, &err);
> > > +        if (unlikely(r < 0)) {
> > > +            goto err_migration_blocker;
> > > +        }
> > > +    }
> > > +
> > >      for (i = 0; i < v->shadow_vqs->len; ++i) {
> > >          VirtQueue *vq = virtio_get_queue(dev->vdev, dev->vq_index + i);
> > >          VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i);
> > > @@ -1064,6 +1072,9 @@ err:
> > >          vhost_svq_stop(svq);
> > >      }
> > >
> > > +err_migration_blocker:
> > > +    error_reportf_err(err, "Cannot setup SVQ %u: ", i);
> > > +
> > >      return false;
> > >  }
> > >
> > > @@ -1083,6 +1094,9 @@ static bool vhost_vdpa_svqs_stop(struct vhost_dev 
> > > *dev)
> > >          }
> > >      }
> > >
> > > +    if (v->migration_blocker) {
> > > +        migrate_del_blocker(v->migration_blocker);
> > > +    }
> > >      return true;
> > >  }
> > >
> > > --
> > > 2.31.1
> > >
> >
>