Re: [PATCH RFC v2 3/4] virtio: allow finalize_features to fail

Michael S. Tsirkin
2014-12-08T07:30:58Z

On Fri, Dec 05, 2014 at 10:53:54AM +0100, David Hildenbrand wrote:
> > This will make it easy for transports to validate features and return
> > failure.
> >
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> > include/linux/virtio_config.h | 3 ++-
> > drivers/lguest/lguest_device.c | 4 +++-
> > drivers/misc/mic/card/mic_virtio.c | 4 +++-
> > drivers/remoteproc/remoteproc_virtio.c | 4 +++-
> > drivers/s390/kvm/kvm_virtio.c | 4 +++-
> > drivers/s390/kvm/virtio_ccw.c | 6 ++++--
> > drivers/virtio/virtio.c | 4 +++-
> > drivers/virtio/virtio_mmio.c | 4 +++-
> > drivers/virtio/virtio_pci.c | 4 +++-
> > 9 files changed, 27 insertions(+), 10 deletions(-)
> >
> > diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> > index 1fa5faa..7979f85 100644
> > --- a/include/linux/virtio_config.h
> > +++ b/include/linux/virtio_config.h
> > @@ -47,6 +47,7 @@
> > * vdev: the virtio_device
> > * This gives the final feature bits for the device: it can change
> > * the dev->feature bits if it wants.
> > + * Returns 0 on success or error status
>
> "Returns 0 on success, otherwise the error status."

It's what other functions say.
I'm ok with changing this but let's do it in a separate patch.

> > * @bus_name: return the bus name associated with the device
> > * vdev: the virtio_device
> > * This returns a pointer to the bus name a la pci_name from which
> > @@ -68,7 +69,7 @@ struct virtio_config_ops {
> > const char *names[]);
> > void (*del_vqs)(struct virtio_device *);
> > u64 (*get_features)(struct virtio_device *vdev);
> > - void (*finalize_features)(struct virtio_device *vdev);
> > + int (*finalize_features)(struct virtio_device *vdev);
> > const char *(*bus_name)(struct virtio_device *vdev);
> > int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
> > };
>
> ...
>
> >
> > static void virtio_ccw_get_config(struct virtio_device *vdev,
> > diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
> > index 6b4c1113..7ddebbc 100644
> > --- a/drivers/virtio/virtio.c
> > +++ b/drivers/virtio/virtio.c
> > @@ -211,7 +211,9 @@ static int virtio_dev_probe(struct device *_d)
> > if (device_features & (1ULL << i))
> > __virtio_set_bit(dev, i);
> >
> > - dev->config->finalize_features(dev);
> > + err = dev->config->finalize_features(dev);
> > + if (err)
> > + goto err;
> >
> > if (virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
> > add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
> > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> > index aec1dae..5219210 100644
> > --- a/drivers/virtio/virtio_mmio.c
> > +++ b/drivers/virtio/virtio_mmio.c
> > @@ -152,7 +152,7 @@ static u64 vm_get_features(struct virtio_device *vdev)
> > return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
> > }
> >
>
> Do we have to take care of fails in virtio_device_restore()?
>
> Otherwise looks good to me.
>
> David